source: src/linux/universal/linux-3.18/net/sctp/sm_statefuns.c @ 31869

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1/* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001-2002 Intel Corp.
6 * Copyright (c) 2002      Nokia Corp.
7 *
8 * This is part of the SCTP Linux Kernel Implementation.
9 *
10 * These are the state functions for the state machine.
11 *
12 * This SCTP implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
16 * any later version.
17 *
18 * This SCTP implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 *                 ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING.  If not, see
26 * <http://www.gnu.org/licenses/>.
27 *
28 * Please send any bug reports or fixes you make to the
29 * email address(es):
30 *    lksctp developers <linux-sctp@vger.kernel.org>
31 *
32 * Written or modified by:
33 *    La Monte H.P. Yarroll <piggy@acm.org>
34 *    Karl Knutson          <karl@athena.chicago.il.us>
35 *    Mathew Kotowsky       <kotowsky@sctp.org>
36 *    Sridhar Samudrala     <samudrala@us.ibm.com>
37 *    Jon Grimm             <jgrimm@us.ibm.com>
38 *    Hui Huang             <hui.huang@nokia.com>
39 *    Dajiang Zhang         <dajiang.zhang@nokia.com>
40 *    Daisy Chang           <daisyc@us.ibm.com>
41 *    Ardelle Fan           <ardelle.fan@intel.com>
42 *    Ryan Layer            <rmlayer@us.ibm.com>
43 *    Kevin Gao             <kevin.gao@intel.com>
44 */
45
46#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
47
48#include <linux/types.h>
49#include <linux/kernel.h>
50#include <linux/ip.h>
51#include <linux/ipv6.h>
52#include <linux/net.h>
53#include <linux/inet.h>
54#include <linux/slab.h>
55#include <net/sock.h>
56#include <net/inet_ecn.h>
57#include <linux/skbuff.h>
58#include <net/sctp/sctp.h>
59#include <net/sctp/sm.h>
60#include <net/sctp/structs.h>
61
62static struct sctp_packet *sctp_abort_pkt_new(struct net *net,
63                                  const struct sctp_endpoint *ep,
64                                  const struct sctp_association *asoc,
65                                  struct sctp_chunk *chunk,
66                                  const void *payload,
67                                  size_t paylen);
68static int sctp_eat_data(const struct sctp_association *asoc,
69                         struct sctp_chunk *chunk,
70                         sctp_cmd_seq_t *commands);
71static struct sctp_packet *sctp_ootb_pkt_new(struct net *net,
72                                             const struct sctp_association *asoc,
73                                             const struct sctp_chunk *chunk);
74static void sctp_send_stale_cookie_err(struct net *net,
75                                       const struct sctp_endpoint *ep,
76                                       const struct sctp_association *asoc,
77                                       const struct sctp_chunk *chunk,
78                                       sctp_cmd_seq_t *commands,
79                                       struct sctp_chunk *err_chunk);
80static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
81                                                 const struct sctp_endpoint *ep,
82                                                 const struct sctp_association *asoc,
83                                                 const sctp_subtype_t type,
84                                                 void *arg,
85                                                 sctp_cmd_seq_t *commands);
86static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net,
87                                             const struct sctp_endpoint *ep,
88                                             const struct sctp_association *asoc,
89                                             const sctp_subtype_t type,
90                                             void *arg,
91                                             sctp_cmd_seq_t *commands);
92static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net,
93                                        const struct sctp_endpoint *ep,
94                                        const struct sctp_association *asoc,
95                                        const sctp_subtype_t type,
96                                        void *arg,
97                                        sctp_cmd_seq_t *commands);
98static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
99
100static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
101                                           sctp_cmd_seq_t *commands,
102                                           __be16 error, int sk_err,
103                                           const struct sctp_association *asoc,
104                                           struct sctp_transport *transport);
105
106static sctp_disposition_t sctp_sf_abort_violation(
107                                     struct net *net,
108                                     const struct sctp_endpoint *ep,
109                                     const struct sctp_association *asoc,
110                                     void *arg,
111                                     sctp_cmd_seq_t *commands,
112                                     const __u8 *payload,
113                                     const size_t paylen);
114
115static sctp_disposition_t sctp_sf_violation_chunklen(
116                                     struct net *net,
117                                     const struct sctp_endpoint *ep,
118                                     const struct sctp_association *asoc,
119                                     const sctp_subtype_t type,
120                                     void *arg,
121                                     sctp_cmd_seq_t *commands);
122
123static sctp_disposition_t sctp_sf_violation_paramlen(
124                                     struct net *net,
125                                     const struct sctp_endpoint *ep,
126                                     const struct sctp_association *asoc,
127                                     const sctp_subtype_t type,
128                                     void *arg, void *ext,
129                                     sctp_cmd_seq_t *commands);
130
131static sctp_disposition_t sctp_sf_violation_ctsn(
132                                     struct net *net,
133                                     const struct sctp_endpoint *ep,
134                                     const struct sctp_association *asoc,
135                                     const sctp_subtype_t type,
136                                     void *arg,
137                                     sctp_cmd_seq_t *commands);
138
139static sctp_disposition_t sctp_sf_violation_chunk(
140                                     struct net *net,
141                                     const struct sctp_endpoint *ep,
142                                     const struct sctp_association *asoc,
143                                     const sctp_subtype_t type,
144                                     void *arg,
145                                     sctp_cmd_seq_t *commands);
146
147static sctp_ierror_t sctp_sf_authenticate(struct net *net,
148                                    const struct sctp_endpoint *ep,
149                                    const struct sctp_association *asoc,
150                                    const sctp_subtype_t type,
151                                    struct sctp_chunk *chunk);
152
153static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
154                                        const struct sctp_endpoint *ep,
155                                        const struct sctp_association *asoc,
156                                        const sctp_subtype_t type,
157                                        void *arg,
158                                        sctp_cmd_seq_t *commands);
159
160/* Small helper function that checks if the chunk length
161 * is of the appropriate length.  The 'required_length' argument
162 * is set to be the size of a specific chunk we are testing.
163 * Return Values:  1 = Valid length
164 *                 0 = Invalid length
165 *
166 */
167static inline int
168sctp_chunk_length_valid(struct sctp_chunk *chunk,
169                           __u16 required_length)
170{
171        __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
172
173        /* Previously already marked? */
174        if (unlikely(chunk->pdiscard))
175                return 0;
176        if (unlikely(chunk_length < required_length))
177                return 0;
178
179        return 1;
180}
181
182/**********************************************************
183 * These are the state functions for handling chunk events.
184 **********************************************************/
185
186/*
187 * Process the final SHUTDOWN COMPLETE.
188 *
189 * Section: 4 (C) (diagram), 9.2
190 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
191 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
192 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
193 * should stop the T2-shutdown timer and remove all knowledge of the
194 * association (and thus the association enters the CLOSED state).
195 *
196 * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
197 * C) Rules for packet carrying SHUTDOWN COMPLETE:
198 * ...
199 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
200 *   if the Verification Tag field of the packet matches its own tag and
201 *   the T bit is not set
202 *   OR
203 *   it is set to its peer's tag and the T bit is set in the Chunk
204 *   Flags.
205 *   Otherwise, the receiver MUST silently discard the packet
206 *   and take no further action.  An endpoint MUST ignore the
207 *   SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
208 *
209 * Inputs
210 * (endpoint, asoc, chunk)
211 *
212 * Outputs
213 * (asoc, reply_msg, msg_up, timers, counters)
214 *
215 * The return value is the disposition of the chunk.
216 */
217sctp_disposition_t sctp_sf_do_4_C(struct net *net,
218                                  const struct sctp_endpoint *ep,
219                                  const struct sctp_association *asoc,
220                                  const sctp_subtype_t type,
221                                  void *arg,
222                                  sctp_cmd_seq_t *commands)
223{
224        struct sctp_chunk *chunk = arg;
225        struct sctp_ulpevent *ev;
226
227        if (!sctp_vtag_verify_either(chunk, asoc))
228                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
229
230        /* RFC 2960 6.10 Bundling
231         *
232         * An endpoint MUST NOT bundle INIT, INIT ACK or
233         * SHUTDOWN COMPLETE with any other chunks.
234         */
235        if (!chunk->singleton)
236                return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
237
238        /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
239        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
240                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
241                                                  commands);
242
243        /* RFC 2960 10.2 SCTP-to-ULP
244         *
245         * H) SHUTDOWN COMPLETE notification
246         *
247         * When SCTP completes the shutdown procedures (section 9.2) this
248         * notification is passed to the upper layer.
249         */
250        ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
251                                             0, 0, 0, NULL, GFP_ATOMIC);
252        if (ev)
253                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
254                                SCTP_ULPEVENT(ev));
255
256        /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
257         * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
258         * not the chunk should be discarded. If the endpoint is in
259         * the SHUTDOWN-ACK-SENT state the endpoint should stop the
260         * T2-shutdown timer and remove all knowledge of the
261         * association (and thus the association enters the CLOSED
262         * state).
263         */
264        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
265                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
266
267        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
268                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
269
270        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
271                        SCTP_STATE(SCTP_STATE_CLOSED));
272
273        SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
274        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
275
276        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
277
278        return SCTP_DISPOSITION_DELETE_TCB;
279}
280
281/*
282 * Respond to a normal INIT chunk.
283 * We are the side that is being asked for an association.
284 *
285 * Section: 5.1 Normal Establishment of an Association, B
286 * B) "Z" shall respond immediately with an INIT ACK chunk.  The
287 *    destination IP address of the INIT ACK MUST be set to the source
288 *    IP address of the INIT to which this INIT ACK is responding.  In
289 *    the response, besides filling in other parameters, "Z" must set the
290 *    Verification Tag field to Tag_A, and also provide its own
291 *    Verification Tag (Tag_Z) in the Initiate Tag field.
292 *
293 * Verification Tag: Must be 0.
294 *
295 * Inputs
296 * (endpoint, asoc, chunk)
297 *
298 * Outputs
299 * (asoc, reply_msg, msg_up, timers, counters)
300 *
301 * The return value is the disposition of the chunk.
302 */
303sctp_disposition_t sctp_sf_do_5_1B_init(struct net *net,
304                                        const struct sctp_endpoint *ep,
305                                        const struct sctp_association *asoc,
306                                        const sctp_subtype_t type,
307                                        void *arg,
308                                        sctp_cmd_seq_t *commands)
309{
310        struct sctp_chunk *chunk = arg;
311        struct sctp_chunk *repl;
312        struct sctp_association *new_asoc;
313        struct sctp_chunk *err_chunk;
314        struct sctp_packet *packet;
315        sctp_unrecognized_param_t *unk_param;
316        int len;
317
318        /* 6.10 Bundling
319         * An endpoint MUST NOT bundle INIT, INIT ACK or
320         * SHUTDOWN COMPLETE with any other chunks.
321         *
322         * IG Section 2.11.2
323         * Furthermore, we require that the receiver of an INIT chunk MUST
324         * enforce these rules by silently discarding an arriving packet
325         * with an INIT chunk that is bundled with other chunks.
326         */
327        if (!chunk->singleton)
328                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
329
330        /* If the packet is an OOTB packet which is temporarily on the
331         * control endpoint, respond with an ABORT.
332         */
333        if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
334                SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
335                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
336        }
337
338        /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
339         * Tag.
340         */
341        if (chunk->sctp_hdr->vtag != 0)
342                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
343
344        /* Make sure that the INIT chunk has a valid length.
345         * Normally, this would cause an ABORT with a Protocol Violation
346         * error, but since we don't have an association, we'll
347         * just discard the packet.
348         */
349        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
350                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
351
352        /* If the INIT is coming toward a closing socket, we'll send back
353         * and ABORT.  Essentially, this catches the race of INIT being
354         * backloged to the socket at the same time as the user isses close().
355         * Since the socket and all its associations are going away, we
356         * can treat this OOTB
357         */
358        if (sctp_sstate(ep->base.sk, CLOSING))
359                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
360
361        /* Verify the INIT chunk before processing it. */
362        err_chunk = NULL;
363        if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
364                              (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
365                              &err_chunk)) {
366                /* This chunk contains fatal error. It is to be discarded.
367                 * Send an ABORT, with causes if there is any.
368                 */
369                if (err_chunk) {
370                        packet = sctp_abort_pkt_new(net, ep, asoc, arg,
371                                        (__u8 *)(err_chunk->chunk_hdr) +
372                                        sizeof(sctp_chunkhdr_t),
373                                        ntohs(err_chunk->chunk_hdr->length) -
374                                        sizeof(sctp_chunkhdr_t));
375
376                        sctp_chunk_free(err_chunk);
377
378                        if (packet) {
379                                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
380                                                SCTP_PACKET(packet));
381                                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
382                                return SCTP_DISPOSITION_CONSUME;
383                        } else {
384                                return SCTP_DISPOSITION_NOMEM;
385                        }
386                } else {
387                        return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
388                                                    commands);
389                }
390        }
391
392        /* Grab the INIT header.  */
393        chunk->subh.init_hdr = (sctp_inithdr_t *)chunk->skb->data;
394
395        /* Tag the variable length parameters.  */
396        chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
397
398        new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
399        if (!new_asoc)
400                goto nomem;
401
402        if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
403                                             sctp_scope(sctp_source(chunk)),
404                                             GFP_ATOMIC) < 0)
405                goto nomem_init;
406
407        /* The call, sctp_process_init(), can fail on memory allocation.  */
408        if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
409                               (sctp_init_chunk_t *)chunk->chunk_hdr,
410                               GFP_ATOMIC))
411                goto nomem_init;
412
413        /* B) "Z" shall respond immediately with an INIT ACK chunk.  */
414
415        /* If there are errors need to be reported for unknown parameters,
416         * make sure to reserve enough room in the INIT ACK for them.
417         */
418        len = 0;
419        if (err_chunk)
420                len = ntohs(err_chunk->chunk_hdr->length) -
421                        sizeof(sctp_chunkhdr_t);
422
423        repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
424        if (!repl)
425                goto nomem_init;
426
427        /* If there are errors need to be reported for unknown parameters,
428         * include them in the outgoing INIT ACK as "Unrecognized parameter"
429         * parameter.
430         */
431        if (err_chunk) {
432                /* Get the "Unrecognized parameter" parameter(s) out of the
433                 * ERROR chunk generated by sctp_verify_init(). Since the
434                 * error cause code for "unknown parameter" and the
435                 * "Unrecognized parameter" type is the same, we can
436                 * construct the parameters in INIT ACK by copying the
437                 * ERROR causes over.
438                 */
439                unk_param = (sctp_unrecognized_param_t *)
440                            ((__u8 *)(err_chunk->chunk_hdr) +
441                            sizeof(sctp_chunkhdr_t));
442                /* Replace the cause code with the "Unrecognized parameter"
443                 * parameter type.
444                 */
445                sctp_addto_chunk(repl, len, unk_param);
446                sctp_chunk_free(err_chunk);
447        }
448
449        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
450
451        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
452
453        /*
454         * Note:  After sending out INIT ACK with the State Cookie parameter,
455         * "Z" MUST NOT allocate any resources, nor keep any states for the
456         * new association.  Otherwise, "Z" will be vulnerable to resource
457         * attacks.
458         */
459        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
460
461        return SCTP_DISPOSITION_DELETE_TCB;
462
463nomem_init:
464        sctp_association_free(new_asoc);
465nomem:
466        if (err_chunk)
467                sctp_chunk_free(err_chunk);
468        return SCTP_DISPOSITION_NOMEM;
469}
470
471/*
472 * Respond to a normal INIT ACK chunk.
473 * We are the side that is initiating the association.
474 *
475 * Section: 5.1 Normal Establishment of an Association, C
476 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
477 *    timer and leave COOKIE-WAIT state. "A" shall then send the State
478 *    Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
479 *    the T1-cookie timer, and enter the COOKIE-ECHOED state.
480 *
481 *    Note: The COOKIE ECHO chunk can be bundled with any pending outbound
482 *    DATA chunks, but it MUST be the first chunk in the packet and
483 *    until the COOKIE ACK is returned the sender MUST NOT send any
484 *    other packets to the peer.
485 *
486 * Verification Tag: 3.3.3
487 *   If the value of the Initiate Tag in a received INIT ACK chunk is
488 *   found to be 0, the receiver MUST treat it as an error and close the
489 *   association by transmitting an ABORT.
490 *
491 * Inputs
492 * (endpoint, asoc, chunk)
493 *
494 * Outputs
495 * (asoc, reply_msg, msg_up, timers, counters)
496 *
497 * The return value is the disposition of the chunk.
498 */
499sctp_disposition_t sctp_sf_do_5_1C_ack(struct net *net,
500                                       const struct sctp_endpoint *ep,
501                                       const struct sctp_association *asoc,
502                                       const sctp_subtype_t type,
503                                       void *arg,
504                                       sctp_cmd_seq_t *commands)
505{
506        struct sctp_chunk *chunk = arg;
507        sctp_init_chunk_t *initchunk;
508        struct sctp_chunk *err_chunk;
509        struct sctp_packet *packet;
510
511        if (!sctp_vtag_verify(chunk, asoc))
512                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
513
514        /* 6.10 Bundling
515         * An endpoint MUST NOT bundle INIT, INIT ACK or
516         * SHUTDOWN COMPLETE with any other chunks.
517         */
518        if (!chunk->singleton)
519                return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
520
521        /* Make sure that the INIT-ACK chunk has a valid length */
522        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_initack_chunk_t)))
523                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
524                                                  commands);
525        /* Grab the INIT header.  */
526        chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
527
528        /* Verify the INIT chunk before processing it. */
529        err_chunk = NULL;
530        if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
531                              (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
532                              &err_chunk)) {
533
534                sctp_error_t error = SCTP_ERROR_NO_RESOURCE;
535
536                /* This chunk contains fatal error. It is to be discarded.
537                 * Send an ABORT, with causes.  If there are no causes,
538                 * then there wasn't enough memory.  Just terminate
539                 * the association.
540                 */
541                if (err_chunk) {
542                        packet = sctp_abort_pkt_new(net, ep, asoc, arg,
543                                        (__u8 *)(err_chunk->chunk_hdr) +
544                                        sizeof(sctp_chunkhdr_t),
545                                        ntohs(err_chunk->chunk_hdr->length) -
546                                        sizeof(sctp_chunkhdr_t));
547
548                        sctp_chunk_free(err_chunk);
549
550                        if (packet) {
551                                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
552                                                SCTP_PACKET(packet));
553                                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
554                                error = SCTP_ERROR_INV_PARAM;
555                        }
556                }
557
558                /* SCTP-AUTH, Section 6.3:
559                 *    It should be noted that if the receiver wants to tear
560                 *    down an association in an authenticated way only, the
561                 *    handling of malformed packets should not result in
562                 *    tearing down the association.
563                 *
564                 * This means that if we only want to abort associations
565                 * in an authenticated way (i.e AUTH+ABORT), then we
566                 * can't destroy this association just because the packet
567                 * was malformed.
568                 */
569                if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
570                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
571
572                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
573                return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
574                                                asoc, chunk->transport);
575        }
576
577        /* Tag the variable length parameters.  Note that we never
578         * convert the parameters in an INIT chunk.
579         */
580        chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
581
582        initchunk = (sctp_init_chunk_t *) chunk->chunk_hdr;
583
584        sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
585                        SCTP_PEER_INIT(initchunk));
586
587        /* Reset init error count upon receipt of INIT-ACK.  */
588        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
589
590        /* 5.1 C) "A" shall stop the T1-init timer and leave
591         * COOKIE-WAIT state.  "A" shall then ... start the T1-cookie
592         * timer, and enter the COOKIE-ECHOED state.
593         */
594        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
595                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
596        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
597                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
598        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
599                        SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
600
601        /* SCTP-AUTH: genereate the assocition shared keys so that
602         * we can potentially signe the COOKIE-ECHO.
603         */
604        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
605
606        /* 5.1 C) "A" shall then send the State Cookie received in the
607         * INIT ACK chunk in a COOKIE ECHO chunk, ...
608         */
609        /* If there is any errors to report, send the ERROR chunk generated
610         * for unknown parameters as well.
611         */
612        sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
613                        SCTP_CHUNK(err_chunk));
614
615        return SCTP_DISPOSITION_CONSUME;
616}
617
618/*
619 * Respond to a normal COOKIE ECHO chunk.
620 * We are the side that is being asked for an association.
621 *
622 * Section: 5.1 Normal Establishment of an Association, D
623 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
624 *    with a COOKIE ACK chunk after building a TCB and moving to
625 *    the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
626 *    any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
627 *    chunk MUST be the first chunk in the packet.
628 *
629 *   IMPLEMENTATION NOTE: An implementation may choose to send the
630 *   Communication Up notification to the SCTP user upon reception
631 *   of a valid COOKIE ECHO chunk.
632 *
633 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
634 * D) Rules for packet carrying a COOKIE ECHO
635 *
636 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
637 *   Initial Tag received in the INIT ACK.
638 *
639 * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
640 *
641 * Inputs
642 * (endpoint, asoc, chunk)
643 *
644 * Outputs
645 * (asoc, reply_msg, msg_up, timers, counters)
646 *
647 * The return value is the disposition of the chunk.
648 */
649sctp_disposition_t sctp_sf_do_5_1D_ce(struct net *net,
650                                      const struct sctp_endpoint *ep,
651                                      const struct sctp_association *asoc,
652                                      const sctp_subtype_t type, void *arg,
653                                      sctp_cmd_seq_t *commands)
654{
655        struct sctp_chunk *chunk = arg;
656        struct sctp_association *new_asoc;
657        sctp_init_chunk_t *peer_init;
658        struct sctp_chunk *repl;
659        struct sctp_ulpevent *ev, *ai_ev = NULL;
660        int error = 0;
661        struct sctp_chunk *err_chk_p;
662        struct sock *sk;
663
664        /* If the packet is an OOTB packet which is temporarily on the
665         * control endpoint, respond with an ABORT.
666         */
667        if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
668                SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
669                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
670        }
671
672        /* Make sure that the COOKIE_ECHO chunk has a valid length.
673         * In this case, we check that we have enough for at least a
674         * chunk header.  More detailed verification is done
675         * in sctp_unpack_cookie().
676         */
677        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
678                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
679
680        /* If the endpoint is not listening or if the number of associations
681         * on the TCP-style socket exceed the max backlog, respond with an
682         * ABORT.
683         */
684        sk = ep->base.sk;
685        if (!sctp_sstate(sk, LISTENING) ||
686            (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
687                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
688
689        /* "Decode" the chunk.  We have no optional parameters so we
690         * are in good shape.
691         */
692        chunk->subh.cookie_hdr =
693                (struct sctp_signed_cookie *)chunk->skb->data;
694        if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
695                                         sizeof(sctp_chunkhdr_t)))
696                goto nomem;
697
698        /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
699         * "Z" will reply with a COOKIE ACK chunk after building a TCB
700         * and moving to the ESTABLISHED state.
701         */
702        new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
703                                      &err_chk_p);
704
705        /* FIXME:
706         * If the re-build failed, what is the proper error path
707         * from here?
708         *
709         * [We should abort the association. --piggy]
710         */
711        if (!new_asoc) {
712                /* FIXME: Several errors are possible.  A bad cookie should
713                 * be silently discarded, but think about logging it too.
714                 */
715                switch (error) {
716                case -SCTP_IERROR_NOMEM:
717                        goto nomem;
718
719                case -SCTP_IERROR_STALE_COOKIE:
720                        sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
721                                                   err_chk_p);
722                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
723
724                case -SCTP_IERROR_BAD_SIG:
725                default:
726                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
727                }
728        }
729
730
731        /* Delay state machine commands until later.
732         *
733         * Re-build the bind address for the association is done in
734         * the sctp_unpack_cookie() already.
735         */
736        /* This is a brand-new association, so these are not yet side
737         * effects--it is safe to run them here.
738         */
739        peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
740
741        if (!sctp_process_init(new_asoc, chunk,
742                               &chunk->subh.cookie_hdr->c.peer_addr,
743                               peer_init, GFP_ATOMIC))
744                goto nomem_init;
745
746        /* SCTP-AUTH:  Now that we've populate required fields in
747         * sctp_process_init, set up the assocaition shared keys as
748         * necessary so that we can potentially authenticate the ACK
749         */
750        error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
751        if (error)
752                goto nomem_init;
753
754        /* SCTP-AUTH:  auth_chunk pointer is only set when the cookie-echo
755         * is supposed to be authenticated and we have to do delayed
756         * authentication.  We've just recreated the association using
757         * the information in the cookie and now it's much easier to
758         * do the authentication.
759         */
760        if (chunk->auth_chunk) {
761                struct sctp_chunk auth;
762                sctp_ierror_t ret;
763
764                /* Make sure that we and the peer are AUTH capable */
765                if (!net->sctp.auth_enable || !new_asoc->peer.auth_capable) {
766                        sctp_association_free(new_asoc);
767                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
768                }
769
770                /* set-up our fake chunk so that we can process it */
771                auth.skb = chunk->auth_chunk;
772                auth.asoc = chunk->asoc;
773                auth.sctp_hdr = chunk->sctp_hdr;
774                auth.chunk_hdr = (sctp_chunkhdr_t *)skb_push(chunk->auth_chunk,
775                                            sizeof(sctp_chunkhdr_t));
776                skb_pull(chunk->auth_chunk, sizeof(sctp_chunkhdr_t));
777                auth.transport = chunk->transport;
778
779                ret = sctp_sf_authenticate(net, ep, new_asoc, type, &auth);
780                if (ret != SCTP_IERROR_NO_ERROR) {
781                        sctp_association_free(new_asoc);
782                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
783                }
784        }
785
786        repl = sctp_make_cookie_ack(new_asoc, chunk);
787        if (!repl)
788                goto nomem_init;
789
790        /* RFC 2960 5.1 Normal Establishment of an Association
791         *
792         * D) IMPLEMENTATION NOTE: An implementation may choose to
793         * send the Communication Up notification to the SCTP user
794         * upon reception of a valid COOKIE ECHO chunk.
795         */
796        ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
797                                             new_asoc->c.sinit_num_ostreams,
798                                             new_asoc->c.sinit_max_instreams,
799                                             NULL, GFP_ATOMIC);
800        if (!ev)
801                goto nomem_ev;
802
803        /* Sockets API Draft Section 5.3.1.6
804         * When a peer sends a Adaptation Layer Indication parameter , SCTP
805         * delivers this notification to inform the application that of the
806         * peers requested adaptation layer.
807         */
808        if (new_asoc->peer.adaptation_ind) {
809                ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
810                                                            GFP_ATOMIC);
811                if (!ai_ev)
812                        goto nomem_aiev;
813        }
814
815        /* Add all the state machine commands now since we've created
816         * everything.  This way we don't introduce memory corruptions
817         * during side-effect processing and correclty count established
818         * associations.
819         */
820        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
821        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
822                        SCTP_STATE(SCTP_STATE_ESTABLISHED));
823        SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
824        SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
825        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
826
827        if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
828                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
829                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
830
831        /* This will send the COOKIE ACK */
832        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
833
834        /* Queue the ASSOC_CHANGE event */
835        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
836
837        /* Send up the Adaptation Layer Indication event */
838        if (ai_ev)
839                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
840                                SCTP_ULPEVENT(ai_ev));
841
842        return SCTP_DISPOSITION_CONSUME;
843
844nomem_aiev:
845        sctp_ulpevent_free(ev);
846nomem_ev:
847        sctp_chunk_free(repl);
848nomem_init:
849        sctp_association_free(new_asoc);
850nomem:
851        return SCTP_DISPOSITION_NOMEM;
852}
853
854/*
855 * Respond to a normal COOKIE ACK chunk.
856 * We are the side that is being asked for an association.
857 *
858 * RFC 2960 5.1 Normal Establishment of an Association
859 *
860 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
861 *    COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
862 *    timer. It may also notify its ULP about the successful
863 *    establishment of the association with a Communication Up
864 *    notification (see Section 10).
865 *
866 * Verification Tag:
867 * Inputs
868 * (endpoint, asoc, chunk)
869 *
870 * Outputs
871 * (asoc, reply_msg, msg_up, timers, counters)
872 *
873 * The return value is the disposition of the chunk.
874 */
875sctp_disposition_t sctp_sf_do_5_1E_ca(struct net *net,
876                                      const struct sctp_endpoint *ep,
877                                      const struct sctp_association *asoc,
878                                      const sctp_subtype_t type, void *arg,
879                                      sctp_cmd_seq_t *commands)
880{
881        struct sctp_chunk *chunk = arg;
882        struct sctp_ulpevent *ev;
883
884        if (!sctp_vtag_verify(chunk, asoc))
885                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
886
887        /* Verify that the chunk length for the COOKIE-ACK is OK.
888         * If we don't do this, any bundled chunks may be junked.
889         */
890        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
891                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
892                                                  commands);
893
894        /* Reset init error count upon receipt of COOKIE-ACK,
895         * to avoid problems with the managemement of this
896         * counter in stale cookie situations when a transition back
897         * from the COOKIE-ECHOED state to the COOKIE-WAIT
898         * state is performed.
899         */
900        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
901
902        /* RFC 2960 5.1 Normal Establishment of an Association
903         *
904         * E) Upon reception of the COOKIE ACK, endpoint "A" will move
905         * from the COOKIE-ECHOED state to the ESTABLISHED state,
906         * stopping the T1-cookie timer.
907         */
908        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
909                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
910        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
911                        SCTP_STATE(SCTP_STATE_ESTABLISHED));
912        SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
913        SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
914        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
915        if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
916                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
917                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
918
919        /* It may also notify its ULP about the successful
920         * establishment of the association with a Communication Up
921         * notification (see Section 10).
922         */
923        ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
924                                             0, asoc->c.sinit_num_ostreams,
925                                             asoc->c.sinit_max_instreams,
926                                             NULL, GFP_ATOMIC);
927
928        if (!ev)
929                goto nomem;
930
931        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
932
933        /* Sockets API Draft Section 5.3.1.6
934         * When a peer sends a Adaptation Layer Indication parameter , SCTP
935         * delivers this notification to inform the application that of the
936         * peers requested adaptation layer.
937         */
938        if (asoc->peer.adaptation_ind) {
939                ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
940                if (!ev)
941                        goto nomem;
942
943                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
944                                SCTP_ULPEVENT(ev));
945        }
946
947        return SCTP_DISPOSITION_CONSUME;
948nomem:
949        return SCTP_DISPOSITION_NOMEM;
950}
951
952/* Generate and sendout a heartbeat packet.  */
953static sctp_disposition_t sctp_sf_heartbeat(const struct sctp_endpoint *ep,
954                                            const struct sctp_association *asoc,
955                                            const sctp_subtype_t type,
956                                            void *arg,
957                                            sctp_cmd_seq_t *commands)
958{
959        struct sctp_transport *transport = (struct sctp_transport *) arg;
960        struct sctp_chunk *reply;
961
962        /* Send a heartbeat to our peer.  */
963        reply = sctp_make_heartbeat(asoc, transport);
964        if (!reply)
965                return SCTP_DISPOSITION_NOMEM;
966
967        /* Set rto_pending indicating that an RTT measurement
968         * is started with this heartbeat chunk.
969         */
970        sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
971                        SCTP_TRANSPORT(transport));
972
973        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
974        return SCTP_DISPOSITION_CONSUME;
975}
976
977/* Generate a HEARTBEAT packet on the given transport.  */
978sctp_disposition_t sctp_sf_sendbeat_8_3(struct net *net,
979                                        const struct sctp_endpoint *ep,
980                                        const struct sctp_association *asoc,
981                                        const sctp_subtype_t type,
982                                        void *arg,
983                                        sctp_cmd_seq_t *commands)
984{
985        struct sctp_transport *transport = (struct sctp_transport *) arg;
986
987        if (asoc->overall_error_count >= asoc->max_retrans) {
988                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
989                                SCTP_ERROR(ETIMEDOUT));
990                /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
991                sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
992                                SCTP_PERR(SCTP_ERROR_NO_ERROR));
993                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
994                SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
995                return SCTP_DISPOSITION_DELETE_TCB;
996        }
997
998        /* Section 3.3.5.
999         * The Sender-specific Heartbeat Info field should normally include
1000         * information about the sender's current time when this HEARTBEAT
1001         * chunk is sent and the destination transport address to which this
1002         * HEARTBEAT is sent (see Section 8.3).
1003         */
1004
1005        if (transport->param_flags & SPP_HB_ENABLE) {
1006                if (SCTP_DISPOSITION_NOMEM ==
1007                                sctp_sf_heartbeat(ep, asoc, type, arg,
1008                                                  commands))
1009                        return SCTP_DISPOSITION_NOMEM;
1010
1011                /* Set transport error counter and association error counter
1012                 * when sending heartbeat.
1013                 */
1014                sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1015                                SCTP_TRANSPORT(transport));
1016        }
1017        sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1018                        SCTP_TRANSPORT(transport));
1019        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1020                        SCTP_TRANSPORT(transport));
1021
1022        return SCTP_DISPOSITION_CONSUME;
1023}
1024
1025/*
1026 * Process an heartbeat request.
1027 *
1028 * Section: 8.3 Path Heartbeat
1029 * The receiver of the HEARTBEAT should immediately respond with a
1030 * HEARTBEAT ACK that contains the Heartbeat Information field copied
1031 * from the received HEARTBEAT chunk.
1032 *
1033 * Verification Tag:  8.5 Verification Tag [Normal verification]
1034 * When receiving an SCTP packet, the endpoint MUST ensure that the
1035 * value in the Verification Tag field of the received SCTP packet
1036 * matches its own Tag. If the received Verification Tag value does not
1037 * match the receiver's own tag value, the receiver shall silently
1038 * discard the packet and shall not process it any further except for
1039 * those cases listed in Section 8.5.1 below.
1040 *
1041 * Inputs
1042 * (endpoint, asoc, chunk)
1043 *
1044 * Outputs
1045 * (asoc, reply_msg, msg_up, timers, counters)
1046 *
1047 * The return value is the disposition of the chunk.
1048 */
1049sctp_disposition_t sctp_sf_beat_8_3(struct net *net,
1050                                    const struct sctp_endpoint *ep,
1051                                    const struct sctp_association *asoc,
1052                                    const sctp_subtype_t type,
1053                                    void *arg,
1054                                    sctp_cmd_seq_t *commands)
1055{
1056        sctp_paramhdr_t *param_hdr;
1057        struct sctp_chunk *chunk = arg;
1058        struct sctp_chunk *reply;
1059        size_t paylen = 0;
1060
1061        if (!sctp_vtag_verify(chunk, asoc))
1062                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1063
1064        /* Make sure that the HEARTBEAT chunk has a valid length. */
1065        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_heartbeat_chunk_t)))
1066                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1067                                                  commands);
1068
1069        /* 8.3 The receiver of the HEARTBEAT should immediately
1070         * respond with a HEARTBEAT ACK that contains the Heartbeat
1071         * Information field copied from the received HEARTBEAT chunk.
1072         */
1073        chunk->subh.hb_hdr = (sctp_heartbeathdr_t *) chunk->skb->data;
1074        param_hdr = (sctp_paramhdr_t *) chunk->subh.hb_hdr;
1075        paylen = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_chunkhdr_t);
1076
1077        if (ntohs(param_hdr->length) > paylen)
1078                return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1079                                                  param_hdr, commands);
1080
1081        if (!pskb_pull(chunk->skb, paylen))
1082                goto nomem;
1083
1084        reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1085        if (!reply)
1086                goto nomem;
1087
1088        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1089        return SCTP_DISPOSITION_CONSUME;
1090
1091nomem:
1092        return SCTP_DISPOSITION_NOMEM;
1093}
1094
1095/*
1096 * Process the returning HEARTBEAT ACK.
1097 *
1098 * Section: 8.3 Path Heartbeat
1099 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1100 * should clear the error counter of the destination transport
1101 * address to which the HEARTBEAT was sent, and mark the destination
1102 * transport address as active if it is not so marked. The endpoint may
1103 * optionally report to the upper layer when an inactive destination
1104 * address is marked as active due to the reception of the latest
1105 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1106 * clear the association overall error count as well (as defined
1107 * in section 8.1).
1108 *
1109 * The receiver of the HEARTBEAT ACK should also perform an RTT
1110 * measurement for that destination transport address using the time
1111 * value carried in the HEARTBEAT ACK chunk.
1112 *
1113 * Verification Tag:  8.5 Verification Tag [Normal verification]
1114 *
1115 * Inputs
1116 * (endpoint, asoc, chunk)
1117 *
1118 * Outputs
1119 * (asoc, reply_msg, msg_up, timers, counters)
1120 *
1121 * The return value is the disposition of the chunk.
1122 */
1123sctp_disposition_t sctp_sf_backbeat_8_3(struct net *net,
1124                                        const struct sctp_endpoint *ep,
1125                                        const struct sctp_association *asoc,
1126                                        const sctp_subtype_t type,
1127                                        void *arg,
1128                                        sctp_cmd_seq_t *commands)
1129{
1130        struct sctp_chunk *chunk = arg;
1131        union sctp_addr from_addr;
1132        struct sctp_transport *link;
1133        sctp_sender_hb_info_t *hbinfo;
1134        unsigned long max_interval;
1135
1136        if (!sctp_vtag_verify(chunk, asoc))
1137                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1138
1139        /* Make sure that the HEARTBEAT-ACK chunk has a valid length.  */
1140        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t) +
1141                                            sizeof(sctp_sender_hb_info_t)))
1142                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1143                                                  commands);
1144
1145        hbinfo = (sctp_sender_hb_info_t *) chunk->skb->data;
1146        /* Make sure that the length of the parameter is what we expect */
1147        if (ntohs(hbinfo->param_hdr.length) !=
1148                                    sizeof(sctp_sender_hb_info_t)) {
1149                return SCTP_DISPOSITION_DISCARD;
1150        }
1151
1152        from_addr = hbinfo->daddr;
1153        link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1154
1155        /* This should never happen, but lets log it if so.  */
1156        if (unlikely(!link)) {
1157                if (from_addr.sa.sa_family == AF_INET6) {
1158                        net_warn_ratelimited("%s association %p could not find address %pI6\n",
1159                                             __func__,
1160                                             asoc,
1161                                             &from_addr.v6.sin6_addr);
1162                } else {
1163                        net_warn_ratelimited("%s association %p could not find address %pI4\n",
1164                                             __func__,
1165                                             asoc,
1166                                             &from_addr.v4.sin_addr.s_addr);
1167                }
1168                return SCTP_DISPOSITION_DISCARD;
1169        }
1170
1171        /* Validate the 64-bit random nonce. */
1172        if (hbinfo->hb_nonce != link->hb_nonce)
1173                return SCTP_DISPOSITION_DISCARD;
1174
1175        max_interval = link->hbinterval + link->rto;
1176
1177        /* Check if the timestamp looks valid.  */
1178        if (time_after(hbinfo->sent_at, jiffies) ||
1179            time_after(jiffies, hbinfo->sent_at + max_interval)) {
1180                pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1181                         "for transport:%p\n", __func__, link);
1182
1183                return SCTP_DISPOSITION_DISCARD;
1184        }
1185
1186        /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1187         * the HEARTBEAT should clear the error counter of the
1188         * destination transport address to which the HEARTBEAT was
1189         * sent and mark the destination transport address as active if
1190         * it is not so marked.
1191         */
1192        sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1193
1194        return SCTP_DISPOSITION_CONSUME;
1195}
1196
1197/* Helper function to send out an abort for the restart
1198 * condition.
1199 */
1200static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1201                                      struct sctp_chunk *init,
1202                                      sctp_cmd_seq_t *commands)
1203{
1204        int len;
1205        struct sctp_packet *pkt;
1206        union sctp_addr_param *addrparm;
1207        struct sctp_errhdr *errhdr;
1208        struct sctp_endpoint *ep;
1209        char buffer[sizeof(struct sctp_errhdr)+sizeof(union sctp_addr_param)];
1210        struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1211
1212        /* Build the error on the stack.   We are way to malloc crazy
1213         * throughout the code today.
1214         */
1215        errhdr = (struct sctp_errhdr *)buffer;
1216        addrparm = (union sctp_addr_param *)errhdr->variable;
1217
1218        /* Copy into a parm format. */
1219        len = af->to_addr_param(ssa, addrparm);
1220        len += sizeof(sctp_errhdr_t);
1221
1222        errhdr->cause = SCTP_ERROR_RESTART;
1223        errhdr->length = htons(len);
1224
1225        /* Assign to the control socket. */
1226        ep = sctp_sk(net->sctp.ctl_sock)->ep;
1227
1228        /* Association is NULL since this may be a restart attack and we
1229         * want to send back the attacker's vtag.
1230         */
1231        pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1232
1233        if (!pkt)
1234                goto out;
1235        sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1236
1237        SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1238
1239        /* Discard the rest of the inbound packet. */
1240        sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1241
1242out:
1243        /* Even if there is no memory, treat as a failure so
1244         * the packet will get dropped.
1245         */
1246        return 0;
1247}
1248
1249static bool list_has_sctp_addr(const struct list_head *list,
1250                               union sctp_addr *ipaddr)
1251{
1252        struct sctp_transport *addr;
1253
1254        list_for_each_entry(addr, list, transports) {
1255                if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1256                        return true;
1257        }
1258
1259        return false;
1260}
1261/* A restart is occurring, check to make sure no new addresses
1262 * are being added as we may be under a takeover attack.
1263 */
1264static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1265                                       const struct sctp_association *asoc,
1266                                       struct sctp_chunk *init,
1267                                       sctp_cmd_seq_t *commands)
1268{
1269        struct net *net = sock_net(new_asoc->base.sk);
1270        struct sctp_transport *new_addr;
1271        int ret = 1;
1272
1273        /* Implementor's Guide - Section 5.2.2
1274         * ...
1275         * Before responding the endpoint MUST check to see if the
1276         * unexpected INIT adds new addresses to the association. If new
1277         * addresses are added to the association, the endpoint MUST respond
1278         * with an ABORT..
1279         */
1280
1281        /* Search through all current addresses and make sure
1282         * we aren't adding any new ones.
1283         */
1284        list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1285                            transports) {
1286                if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1287                                        &new_addr->ipaddr)) {
1288                        sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1289                                                   commands);
1290                        ret = 0;
1291                        break;
1292                }
1293        }
1294
1295        /* Return success if all addresses were found. */
1296        return ret;
1297}
1298
1299/* Populate the verification/tie tags based on overlapping INIT
1300 * scenario.
1301 *
1302 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1303 */
1304static void sctp_tietags_populate(struct sctp_association *new_asoc,
1305                                  const struct sctp_association *asoc)
1306{
1307        switch (asoc->state) {
1308
1309        /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1310
1311        case SCTP_STATE_COOKIE_WAIT:
1312                new_asoc->c.my_vtag     = asoc->c.my_vtag;
1313                new_asoc->c.my_ttag     = asoc->c.my_vtag;
1314                new_asoc->c.peer_ttag   = 0;
1315                break;
1316
1317        case SCTP_STATE_COOKIE_ECHOED:
1318                new_asoc->c.my_vtag     = asoc->c.my_vtag;
1319                new_asoc->c.my_ttag     = asoc->c.my_vtag;
1320                new_asoc->c.peer_ttag   = asoc->c.peer_vtag;
1321                break;
1322
1323        /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1324         * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1325         */
1326        default:
1327                new_asoc->c.my_ttag   = asoc->c.my_vtag;
1328                new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1329                break;
1330        }
1331
1332        /* Other parameters for the endpoint SHOULD be copied from the
1333         * existing parameters of the association (e.g. number of
1334         * outbound streams) into the INIT ACK and cookie.
1335         */
1336        new_asoc->rwnd                  = asoc->rwnd;
1337        new_asoc->c.sinit_num_ostreams  = asoc->c.sinit_num_ostreams;
1338        new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1339        new_asoc->c.initial_tsn         = asoc->c.initial_tsn;
1340}
1341
1342/*
1343 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1344 * handling action.
1345 *
1346 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1347 *
1348 * Returns value representing action to be taken.   These action values
1349 * correspond to Action/Description values in RFC 2960, Table 2.
1350 */
1351static char sctp_tietags_compare(struct sctp_association *new_asoc,
1352                                 const struct sctp_association *asoc)
1353{
1354        /* In this case, the peer may have restarted.  */
1355        if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1356            (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1357            (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1358            (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1359                return 'A';
1360
1361        /* Collision case B. */
1362        if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1363            ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1364             (0 == asoc->c.peer_vtag))) {
1365                return 'B';
1366        }
1367
1368        /* Collision case D. */
1369        if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1370            (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1371                return 'D';
1372
1373        /* Collision case C. */
1374        if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1375            (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1376            (0 == new_asoc->c.my_ttag) &&
1377            (0 == new_asoc->c.peer_ttag))
1378                return 'C';
1379
1380        /* No match to any of the special cases; discard this packet. */
1381        return 'E';
1382}
1383
1384/* Common helper routine for both duplicate and simulataneous INIT
1385 * chunk handling.
1386 */
1387static sctp_disposition_t sctp_sf_do_unexpected_init(
1388        struct net *net,
1389        const struct sctp_endpoint *ep,
1390        const struct sctp_association *asoc,
1391        const sctp_subtype_t type,
1392        void *arg, sctp_cmd_seq_t *commands)
1393{
1394        sctp_disposition_t retval;
1395        struct sctp_chunk *chunk = arg;
1396        struct sctp_chunk *repl;
1397        struct sctp_association *new_asoc;
1398        struct sctp_chunk *err_chunk;
1399        struct sctp_packet *packet;
1400        sctp_unrecognized_param_t *unk_param;
1401        int len;
1402
1403        /* 6.10 Bundling
1404         * An endpoint MUST NOT bundle INIT, INIT ACK or
1405         * SHUTDOWN COMPLETE with any other chunks.
1406         *
1407         * IG Section 2.11.2
1408         * Furthermore, we require that the receiver of an INIT chunk MUST
1409         * enforce these rules by silently discarding an arriving packet
1410         * with an INIT chunk that is bundled with other chunks.
1411         */
1412        if (!chunk->singleton)
1413                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1414
1415        /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1416         * Tag.
1417         */
1418        if (chunk->sctp_hdr->vtag != 0)
1419                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1420
1421        /* Make sure that the INIT chunk has a valid length.
1422         * In this case, we generate a protocol violation since we have
1423         * an association established.
1424         */
1425        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_init_chunk_t)))
1426                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1427                                                  commands);
1428        /* Grab the INIT header.  */
1429        chunk->subh.init_hdr = (sctp_inithdr_t *) chunk->skb->data;
1430
1431        /* Tag the variable length parameters.  */
1432        chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(sctp_inithdr_t));
1433
1434        /* Verify the INIT chunk before processing it. */
1435        err_chunk = NULL;
1436        if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1437                              (sctp_init_chunk_t *)chunk->chunk_hdr, chunk,
1438                              &err_chunk)) {
1439                /* This chunk contains fatal error. It is to be discarded.
1440                 * Send an ABORT, with causes if there is any.
1441                 */
1442                if (err_chunk) {
1443                        packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1444                                        (__u8 *)(err_chunk->chunk_hdr) +
1445                                        sizeof(sctp_chunkhdr_t),
1446                                        ntohs(err_chunk->chunk_hdr->length) -
1447                                        sizeof(sctp_chunkhdr_t));
1448
1449                        if (packet) {
1450                                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1451                                                SCTP_PACKET(packet));
1452                                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1453                                retval = SCTP_DISPOSITION_CONSUME;
1454                        } else {
1455                                retval = SCTP_DISPOSITION_NOMEM;
1456                        }
1457                        goto cleanup;
1458                } else {
1459                        return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1460                                                    commands);
1461                }
1462        }
1463
1464        /*
1465         * Other parameters for the endpoint SHOULD be copied from the
1466         * existing parameters of the association (e.g. number of
1467         * outbound streams) into the INIT ACK and cookie.
1468         * FIXME:  We are copying parameters from the endpoint not the
1469         * association.
1470         */
1471        new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1472        if (!new_asoc)
1473                goto nomem;
1474
1475        if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1476                                sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1477                goto nomem;
1478
1479        /* In the outbound INIT ACK the endpoint MUST copy its current
1480         * Verification Tag and Peers Verification tag into a reserved
1481         * place (local tie-tag and per tie-tag) within the state cookie.
1482         */
1483        if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1484                               (sctp_init_chunk_t *)chunk->chunk_hdr,
1485                               GFP_ATOMIC))
1486                goto nomem;
1487
1488        /* Make sure no new addresses are being added during the
1489         * restart.   Do not do this check for COOKIE-WAIT state,
1490         * since there are no peer addresses to check against.
1491         * Upon return an ABORT will have been sent if needed.
1492         */
1493        if (!sctp_state(asoc, COOKIE_WAIT)) {
1494                if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1495                                                 commands)) {
1496                        retval = SCTP_DISPOSITION_CONSUME;
1497                        goto nomem_retval;
1498                }
1499        }
1500
1501        sctp_tietags_populate(new_asoc, asoc);
1502
1503        /* B) "Z" shall respond immediately with an INIT ACK chunk.  */
1504
1505        /* If there are errors need to be reported for unknown parameters,
1506         * make sure to reserve enough room in the INIT ACK for them.
1507         */
1508        len = 0;
1509        if (err_chunk) {
1510                len = ntohs(err_chunk->chunk_hdr->length) -
1511                        sizeof(sctp_chunkhdr_t);
1512        }
1513
1514        repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1515        if (!repl)
1516                goto nomem;
1517
1518        /* If there are errors need to be reported for unknown parameters,
1519         * include them in the outgoing INIT ACK as "Unrecognized parameter"
1520         * parameter.
1521         */
1522        if (err_chunk) {
1523                /* Get the "Unrecognized parameter" parameter(s) out of the
1524                 * ERROR chunk generated by sctp_verify_init(). Since the
1525                 * error cause code for "unknown parameter" and the
1526                 * "Unrecognized parameter" type is the same, we can
1527                 * construct the parameters in INIT ACK by copying the
1528                 * ERROR causes over.
1529                 */
1530                unk_param = (sctp_unrecognized_param_t *)
1531                            ((__u8 *)(err_chunk->chunk_hdr) +
1532                            sizeof(sctp_chunkhdr_t));
1533                /* Replace the cause code with the "Unrecognized parameter"
1534                 * parameter type.
1535                 */
1536                sctp_addto_chunk(repl, len, unk_param);
1537        }
1538
1539        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1540        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1541
1542        /*
1543         * Note: After sending out INIT ACK with the State Cookie parameter,
1544         * "Z" MUST NOT allocate any resources for this new association.
1545         * Otherwise, "Z" will be vulnerable to resource attacks.
1546         */
1547        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1548        retval = SCTP_DISPOSITION_CONSUME;
1549
1550        return retval;
1551
1552nomem:
1553        retval = SCTP_DISPOSITION_NOMEM;
1554nomem_retval:
1555        if (new_asoc)
1556                sctp_association_free(new_asoc);
1557cleanup:
1558        if (err_chunk)
1559                sctp_chunk_free(err_chunk);
1560        return retval;
1561}
1562
1563/*
1564 * Handle simultaneous INIT.
1565 * This means we started an INIT and then we got an INIT request from
1566 * our peer.
1567 *
1568 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1569 * This usually indicates an initialization collision, i.e., each
1570 * endpoint is attempting, at about the same time, to establish an
1571 * association with the other endpoint.
1572 *
1573 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1574 * endpoint MUST respond with an INIT ACK using the same parameters it
1575 * sent in its original INIT chunk (including its Verification Tag,
1576 * unchanged). These original parameters are combined with those from the
1577 * newly received INIT chunk. The endpoint shall also generate a State
1578 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1579 * INIT to calculate the State Cookie.
1580 *
1581 * After that, the endpoint MUST NOT change its state, the T1-init
1582 * timer shall be left running and the corresponding TCB MUST NOT be
1583 * destroyed. The normal procedures for handling State Cookies when
1584 * a TCB exists will resolve the duplicate INITs to a single association.
1585 *
1586 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1587 * its Tie-Tags with the Tag information of itself and its peer (see
1588 * section 5.2.2 for a description of the Tie-Tags).
1589 *
1590 * Verification Tag: Not explicit, but an INIT can not have a valid
1591 * verification tag, so we skip the check.
1592 *
1593 * Inputs
1594 * (endpoint, asoc, chunk)
1595 *
1596 * Outputs
1597 * (asoc, reply_msg, msg_up, timers, counters)
1598 *
1599 * The return value is the disposition of the chunk.
1600 */
1601sctp_disposition_t sctp_sf_do_5_2_1_siminit(struct net *net,
1602                                    const struct sctp_endpoint *ep,
1603                                    const struct sctp_association *asoc,
1604                                    const sctp_subtype_t type,
1605                                    void *arg,
1606                                    sctp_cmd_seq_t *commands)
1607{
1608        /* Call helper to do the real work for both simulataneous and
1609         * duplicate INIT chunk handling.
1610         */
1611        return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1612}
1613
1614/*
1615 * Handle duplicated INIT messages.  These are usually delayed
1616 * restransmissions.
1617 *
1618 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1619 * COOKIE-ECHOED and COOKIE-WAIT
1620 *
1621 * Unless otherwise stated, upon reception of an unexpected INIT for
1622 * this association, the endpoint shall generate an INIT ACK with a
1623 * State Cookie.  In the outbound INIT ACK the endpoint MUST copy its
1624 * current Verification Tag and peer's Verification Tag into a reserved
1625 * place within the state cookie.  We shall refer to these locations as
1626 * the Peer's-Tie-Tag and the Local-Tie-Tag.  The outbound SCTP packet
1627 * containing this INIT ACK MUST carry a Verification Tag value equal to
1628 * the Initiation Tag found in the unexpected INIT.  And the INIT ACK
1629 * MUST contain a new Initiation Tag (randomly generated see Section
1630 * 5.3.1).  Other parameters for the endpoint SHOULD be copied from the
1631 * existing parameters of the association (e.g. number of outbound
1632 * streams) into the INIT ACK and cookie.
1633 *
1634 * After sending out the INIT ACK, the endpoint shall take no further
1635 * actions, i.e., the existing association, including its current state,
1636 * and the corresponding TCB MUST NOT be changed.
1637 *
1638 * Note: Only when a TCB exists and the association is not in a COOKIE-
1639 * WAIT state are the Tie-Tags populated.  For a normal association INIT
1640 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1641 * set to 0 (indicating that no previous TCB existed).  The INIT ACK and
1642 * State Cookie are populated as specified in section 5.2.1.
1643 *
1644 * Verification Tag: Not specified, but an INIT has no way of knowing
1645 * what the verification tag could be, so we ignore it.
1646 *
1647 * Inputs
1648 * (endpoint, asoc, chunk)
1649 *
1650 * Outputs
1651 * (asoc, reply_msg, msg_up, timers, counters)
1652 *
1653 * The return value is the disposition of the chunk.
1654 */
1655sctp_disposition_t sctp_sf_do_5_2_2_dupinit(struct net *net,
1656                                        const struct sctp_endpoint *ep,
1657                                        const struct sctp_association *asoc,
1658                                        const sctp_subtype_t type,
1659                                        void *arg,
1660                                        sctp_cmd_seq_t *commands)
1661{
1662        /* Call helper to do the real work for both simulataneous and
1663         * duplicate INIT chunk handling.
1664         */
1665        return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1666}
1667
1668
1669/*
1670 * Unexpected INIT-ACK handler.
1671 *
1672 * Section 5.2.3
1673 * If an INIT ACK received by an endpoint in any state other than the
1674 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1675 * An unexpected INIT ACK usually indicates the processing of an old or
1676 * duplicated INIT chunk.
1677*/
1678sctp_disposition_t sctp_sf_do_5_2_3_initack(struct net *net,
1679                                            const struct sctp_endpoint *ep,
1680                                            const struct sctp_association *asoc,
1681                                            const sctp_subtype_t type,
1682                                            void *arg, sctp_cmd_seq_t *commands)
1683{
1684        /* Per the above section, we'll discard the chunk if we have an
1685         * endpoint.  If this is an OOTB INIT-ACK, treat it as such.
1686         */
1687        if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1688                return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1689        else
1690                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1691}
1692
1693/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1694 *
1695 * Section 5.2.4
1696 *  A)  In this case, the peer may have restarted.
1697 */
1698static sctp_disposition_t sctp_sf_do_dupcook_a(struct net *net,
1699                                        const struct sctp_endpoint *ep,
1700                                        const struct sctp_association *asoc,
1701                                        struct sctp_chunk *chunk,
1702                                        sctp_cmd_seq_t *commands,
1703                                        struct sctp_association *new_asoc)
1704{
1705        sctp_init_chunk_t *peer_init;
1706        struct sctp_ulpevent *ev;
1707        struct sctp_chunk *repl;
1708        struct sctp_chunk *err;
1709        sctp_disposition_t disposition;
1710
1711        /* new_asoc is a brand-new association, so these are not yet
1712         * side effects--it is safe to run them here.
1713         */
1714        peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1715
1716        if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1717                               GFP_ATOMIC))
1718                goto nomem;
1719
1720        /* Make sure no new addresses are being added during the
1721         * restart.  Though this is a pretty complicated attack
1722         * since you'd have to get inside the cookie.
1723         */
1724        if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) {
1725                return SCTP_DISPOSITION_CONSUME;
1726        }
1727
1728        /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1729         * the peer has restarted (Action A), it MUST NOT setup a new
1730         * association but instead resend the SHUTDOWN ACK and send an ERROR
1731         * chunk with a "Cookie Received while Shutting Down" error cause to
1732         * its peer.
1733        */
1734        if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1735                disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc,
1736                                SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1737                                chunk, commands);
1738                if (SCTP_DISPOSITION_NOMEM == disposition)
1739                        goto nomem;
1740
1741                err = sctp_make_op_error(asoc, chunk,
1742                                         SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1743                                         NULL, 0, 0);
1744                if (err)
1745                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1746                                        SCTP_CHUNK(err));
1747
1748                return SCTP_DISPOSITION_CONSUME;
1749        }
1750
1751        /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1752         * data. Consider the optional choice of resending of this data.
1753         */
1754        sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1755        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1756                        SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1757        sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1758
1759        /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1760         * and ASCONF-ACK cache.
1761         */
1762        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1763                        SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1764        sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1765
1766        repl = sctp_make_cookie_ack(new_asoc, chunk);
1767        if (!repl)
1768                goto nomem;
1769
1770        /* Report association restart to upper layer. */
1771        ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1772                                             new_asoc->c.sinit_num_ostreams,
1773                                             new_asoc->c.sinit_max_instreams,
1774                                             NULL, GFP_ATOMIC);
1775        if (!ev)
1776                goto nomem_ev;
1777
1778        /* Update the content of current association. */
1779        sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1780        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1781        if (sctp_state(asoc, SHUTDOWN_PENDING) &&
1782            (sctp_sstate(asoc->base.sk, CLOSING) ||
1783             sock_flag(asoc->base.sk, SOCK_DEAD))) {
1784                /* if were currently in SHUTDOWN_PENDING, but the socket
1785                 * has been closed by user, don't transition to ESTABLISHED.
1786                 * Instead trigger SHUTDOWN bundled with COOKIE_ACK.
1787                 */
1788                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1789                return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1790                                                     SCTP_ST_CHUNK(0), NULL,
1791                                                     commands);
1792        } else {
1793                sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1794                                SCTP_STATE(SCTP_STATE_ESTABLISHED));
1795                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1796        }
1797        return SCTP_DISPOSITION_CONSUME;
1798
1799nomem_ev:
1800        sctp_chunk_free(repl);
1801nomem:
1802        return SCTP_DISPOSITION_NOMEM;
1803}
1804
1805/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1806 *
1807 * Section 5.2.4
1808 *   B) In this case, both sides may be attempting to start an association
1809 *      at about the same time but the peer endpoint started its INIT
1810 *      after responding to the local endpoint's INIT
1811 */
1812/* This case represents an initialization collision.  */
1813static sctp_disposition_t sctp_sf_do_dupcook_b(struct net *net,
1814                                        const struct sctp_endpoint *ep,
1815                                        const struct sctp_association *asoc,
1816                                        struct sctp_chunk *chunk,
1817                                        sctp_cmd_seq_t *commands,
1818                                        struct sctp_association *new_asoc)
1819{
1820        sctp_init_chunk_t *peer_init;
1821        struct sctp_chunk *repl;
1822
1823        /* new_asoc is a brand-new association, so these are not yet
1824         * side effects--it is safe to run them here.
1825         */
1826        peer_init = &chunk->subh.cookie_hdr->c.peer_init[0];
1827        if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1828                               GFP_ATOMIC))
1829                goto nomem;
1830
1831        /* Update the content of current association.  */
1832        sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_ASSOC, SCTP_ASOC(new_asoc));
1833        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1834                        SCTP_STATE(SCTP_STATE_ESTABLISHED));
1835        SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1836        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
1837
1838        repl = sctp_make_cookie_ack(new_asoc, chunk);
1839        if (!repl)
1840                goto nomem;
1841
1842        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1843
1844        /* RFC 2960 5.1 Normal Establishment of an Association
1845         *
1846         * D) IMPLEMENTATION NOTE: An implementation may choose to
1847         * send the Communication Up notification to the SCTP user
1848         * upon reception of a valid COOKIE ECHO chunk.
1849         *
1850         * Sadly, this needs to be implemented as a side-effect, because
1851         * we are not guaranteed to have set the association id of the real
1852         * association and so these notifications need to be delayed until
1853         * the association id is allocated.
1854         */
1855
1856        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
1857
1858        /* Sockets API Draft Section 5.3.1.6
1859         * When a peer sends a Adaptation Layer Indication parameter , SCTP
1860         * delivers this notification to inform the application that of the
1861         * peers requested adaptation layer.
1862         *
1863         * This also needs to be done as a side effect for the same reason as
1864         * above.
1865         */
1866        if (asoc->peer.adaptation_ind)
1867                sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
1868
1869        return SCTP_DISPOSITION_CONSUME;
1870
1871nomem:
1872        return SCTP_DISPOSITION_NOMEM;
1873}
1874
1875/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
1876 *
1877 * Section 5.2.4
1878 *  C) In this case, the local endpoint's cookie has arrived late.
1879 *     Before it arrived, the local endpoint sent an INIT and received an
1880 *     INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
1881 *     but a new tag of its own.
1882 */
1883/* This case represents an initialization collision.  */
1884static sctp_disposition_t sctp_sf_do_dupcook_c(struct net *net,
1885                                        const struct sctp_endpoint *ep,
1886                                        const struct sctp_association *asoc,
1887                                        struct sctp_chunk *chunk,
1888                                        sctp_cmd_seq_t *commands,
1889                                        struct sctp_association *new_asoc)
1890{
1891        /* The cookie should be silently discarded.
1892         * The endpoint SHOULD NOT change states and should leave
1893         * any timers running.
1894         */
1895        return SCTP_DISPOSITION_DISCARD;
1896}
1897
1898/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
1899 *
1900 * Section 5.2.4
1901 *
1902 * D) When both local and remote tags match the endpoint should always
1903 *    enter the ESTABLISHED state, if it has not already done so.
1904 */
1905/* This case represents an initialization collision.  */
1906static sctp_disposition_t sctp_sf_do_dupcook_d(struct net *net,
1907                                        const struct sctp_endpoint *ep,
1908                                        const struct sctp_association *asoc,
1909                                        struct sctp_chunk *chunk,
1910                                        sctp_cmd_seq_t *commands,
1911                                        struct sctp_association *new_asoc)
1912{
1913        struct sctp_ulpevent *ev = NULL, *ai_ev = NULL;
1914        struct sctp_chunk *repl;
1915
1916        /* Clarification from Implementor's Guide:
1917         * D) When both local and remote tags match the endpoint should
1918         * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
1919         * It should stop any cookie timer that may be running and send
1920         * a COOKIE ACK.
1921         */
1922
1923        /* Don't accidentally move back into established state. */
1924        if (asoc->state < SCTP_STATE_ESTABLISHED) {
1925                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1926                                SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
1927                sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1928                                SCTP_STATE(SCTP_STATE_ESTABLISHED));
1929                SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
1930                sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
1931                                SCTP_NULL());
1932
1933                /* RFC 2960 5.1 Normal Establishment of an Association
1934                 *
1935                 * D) IMPLEMENTATION NOTE: An implementation may choose
1936                 * to send the Communication Up notification to the
1937                 * SCTP user upon reception of a valid COOKIE
1938                 * ECHO chunk.
1939                 */
1940                ev = sctp_ulpevent_make_assoc_change(asoc, 0,
1941                                             SCTP_COMM_UP, 0,
1942                                             asoc->c.sinit_num_ostreams,
1943                                             asoc->c.sinit_max_instreams,
1944                                             NULL, GFP_ATOMIC);
1945                if (!ev)
1946                        goto nomem;
1947
1948                /* Sockets API Draft Section 5.3.1.6
1949                 * When a peer sends a Adaptation Layer Indication parameter,
1950                 * SCTP delivers this notification to inform the application
1951                 * that of the peers requested adaptation layer.
1952                 */
1953                if (asoc->peer.adaptation_ind) {
1954                        ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
1955                                                                 GFP_ATOMIC);
1956                        if (!ai_ev)
1957                                goto nomem;
1958
1959                }
1960        }
1961
1962        repl = sctp_make_cookie_ack(new_asoc, chunk);
1963        if (!repl)
1964                goto nomem;
1965
1966        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1967
1968        if (ev)
1969                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1970                                SCTP_ULPEVENT(ev));
1971        if (ai_ev)
1972                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1973                                        SCTP_ULPEVENT(ai_ev));
1974
1975        return SCTP_DISPOSITION_CONSUME;
1976
1977nomem:
1978        if (ai_ev)
1979                sctp_ulpevent_free(ai_ev);
1980        if (ev)
1981                sctp_ulpevent_free(ev);
1982        return SCTP_DISPOSITION_NOMEM;
1983}
1984
1985/*
1986 * Handle a duplicate COOKIE-ECHO.  This usually means a cookie-carrying
1987 * chunk was retransmitted and then delayed in the network.
1988 *
1989 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
1990 *
1991 * Verification Tag: None.  Do cookie validation.
1992 *
1993 * Inputs
1994 * (endpoint, asoc, chunk)
1995 *
1996 * Outputs
1997 * (asoc, reply_msg, msg_up, timers, counters)
1998 *
1999 * The return value is the disposition of the chunk.
2000 */
2001sctp_disposition_t sctp_sf_do_5_2_4_dupcook(struct net *net,
2002                                        const struct sctp_endpoint *ep,
2003                                        const struct sctp_association *asoc,
2004                                        const sctp_subtype_t type,
2005                                        void *arg,
2006                                        sctp_cmd_seq_t *commands)
2007{
2008        sctp_disposition_t retval;
2009        struct sctp_chunk *chunk = arg;
2010        struct sctp_association *new_asoc;
2011        int error = 0;
2012        char action;
2013        struct sctp_chunk *err_chk_p;
2014
2015        /* Make sure that the chunk has a valid length from the protocol
2016         * perspective.  In this case check to make sure we have at least
2017         * enough for the chunk header.  Cookie length verification is
2018         * done later.
2019         */
2020        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2021                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2022                                                  commands);
2023
2024        /* "Decode" the chunk.  We have no optional parameters so we
2025         * are in good shape.
2026         */
2027        chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2028        if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2029                                        sizeof(sctp_chunkhdr_t)))
2030                goto nomem;
2031
2032        /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2033         * of a duplicate COOKIE ECHO match the Verification Tags of the
2034         * current association, consider the State Cookie valid even if
2035         * the lifespan is exceeded.
2036         */
2037        new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2038                                      &err_chk_p);
2039
2040        /* FIXME:
2041         * If the re-build failed, what is the proper error path
2042         * from here?
2043         *
2044         * [We should abort the association. --piggy]
2045         */
2046        if (!new_asoc) {
2047                /* FIXME: Several errors are possible.  A bad cookie should
2048                 * be silently discarded, but think about logging it too.
2049                 */
2050                switch (error) {
2051                case -SCTP_IERROR_NOMEM:
2052                        goto nomem;
2053
2054                case -SCTP_IERROR_STALE_COOKIE:
2055                        sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2056                                                   err_chk_p);
2057                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2058                case -SCTP_IERROR_BAD_SIG:
2059                default:
2060                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2061                }
2062        }
2063
2064        /* Compare the tie_tag in cookie with the verification tag of
2065         * current association.
2066         */
2067        action = sctp_tietags_compare(new_asoc, asoc);
2068
2069        switch (action) {
2070        case 'A': /* Association restart. */
2071                retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2072                                              new_asoc);
2073                break;
2074
2075        case 'B': /* Collision case B. */
2076                retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2077                                              new_asoc);
2078                break;
2079
2080        case 'C': /* Collision case C. */
2081                retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2082                                              new_asoc);
2083                break;
2084
2085        case 'D': /* Collision case D. */
2086                retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2087                                              new_asoc);
2088                break;
2089
2090        default: /* Discard packet for all others. */
2091                retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2092                break;
2093        }
2094
2095        /* Delete the tempory new association. */
2096        sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2097        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2098
2099        /* Restore association pointer to provide SCTP command interpeter
2100         * with a valid context in case it needs to manipulate
2101         * the queues */
2102        sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2103                         SCTP_ASOC((struct sctp_association *)asoc));
2104
2105        return retval;
2106
2107nomem:
2108        return SCTP_DISPOSITION_NOMEM;
2109}
2110
2111/*
2112 * Process an ABORT.  (SHUTDOWN-PENDING state)
2113 *
2114 * See sctp_sf_do_9_1_abort().
2115 */
2116sctp_disposition_t sctp_sf_shutdown_pending_abort(
2117        struct net *net,
2118        const struct sctp_endpoint *ep,
2119        const struct sctp_association *asoc,
2120        const sctp_subtype_t type,
2121        void *arg,
2122        sctp_cmd_seq_t *commands)
2123{
2124        struct sctp_chunk *chunk = arg;
2125
2126        if (!sctp_vtag_verify_either(chunk, asoc))
2127                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2128
2129        /* Make sure that the ABORT chunk has a valid length.
2130         * Since this is an ABORT chunk, we have to discard it
2131         * because of the following text:
2132         * RFC 2960, Section 3.3.7
2133         *    If an endpoint receives an ABORT with a format error or for an
2134         *    association that doesn't exist, it MUST silently discard it.
2135         * Because the length is "invalid", we can't really discard just
2136         * as we do not know its true length.  So, to be safe, discard the
2137         * packet.
2138         */
2139        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2140                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2141
2142        /* ADD-IP: Special case for ABORT chunks
2143         * F4)  One special consideration is that ABORT Chunks arriving
2144         * destined to the IP address being deleted MUST be
2145         * ignored (see Section 5.3.1 for further details).
2146         */
2147        if (SCTP_ADDR_DEL ==
2148                    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2149                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2150
2151        return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2152}
2153
2154/*
2155 * Process an ABORT.  (SHUTDOWN-SENT state)
2156 *
2157 * See sctp_sf_do_9_1_abort().
2158 */
2159sctp_disposition_t sctp_sf_shutdown_sent_abort(struct net *net,
2160                                        const struct sctp_endpoint *ep,
2161                                        const struct sctp_association *asoc,
2162                                        const sctp_subtype_t type,
2163                                        void *arg,
2164                                        sctp_cmd_seq_t *commands)
2165{
2166        struct sctp_chunk *chunk = arg;
2167
2168        if (!sctp_vtag_verify_either(chunk, asoc))
2169                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2170
2171        /* Make sure that the ABORT chunk has a valid length.
2172         * Since this is an ABORT chunk, we have to discard it
2173         * because of the following text:
2174         * RFC 2960, Section 3.3.7
2175         *    If an endpoint receives an ABORT with a format error or for an
2176         *    association that doesn't exist, it MUST silently discard it.
2177         * Because the length is "invalid", we can't really discard just
2178         * as we do not know its true length.  So, to be safe, discard the
2179         * packet.
2180         */
2181        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2182                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2183
2184        /* ADD-IP: Special case for ABORT chunks
2185         * F4)  One special consideration is that ABORT Chunks arriving
2186         * destined to the IP address being deleted MUST be
2187         * ignored (see Section 5.3.1 for further details).
2188         */
2189        if (SCTP_ADDR_DEL ==
2190                    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2191                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2192
2193        /* Stop the T2-shutdown timer. */
2194        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2195                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2196
2197        /* Stop the T5-shutdown guard timer.  */
2198        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2199                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2200
2201        return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2202}
2203
2204/*
2205 * Process an ABORT.  (SHUTDOWN-ACK-SENT state)
2206 *
2207 * See sctp_sf_do_9_1_abort().
2208 */
2209sctp_disposition_t sctp_sf_shutdown_ack_sent_abort(
2210        struct net *net,
2211        const struct sctp_endpoint *ep,
2212        const struct sctp_association *asoc,
2213        const sctp_subtype_t type,
2214        void *arg,
2215        sctp_cmd_seq_t *commands)
2216{
2217        /* The same T2 timer, so we should be able to use
2218         * common function with the SHUTDOWN-SENT state.
2219         */
2220        return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2221}
2222
2223/*
2224 * Handle an Error received in COOKIE_ECHOED state.
2225 *
2226 * Only handle the error type of stale COOKIE Error, the other errors will
2227 * be ignored.
2228 *
2229 * Inputs
2230 * (endpoint, asoc, chunk)
2231 *
2232 * Outputs
2233 * (asoc, reply_msg, msg_up, timers, counters)
2234 *
2235 * The return value is the disposition of the chunk.
2236 */
2237sctp_disposition_t sctp_sf_cookie_echoed_err(struct net *net,
2238                                        const struct sctp_endpoint *ep,
2239                                        const struct sctp_association *asoc,
2240                                        const sctp_subtype_t type,
2241                                        void *arg,
2242                                        sctp_cmd_seq_t *commands)
2243{
2244        struct sctp_chunk *chunk = arg;
2245        sctp_errhdr_t *err;
2246
2247        if (!sctp_vtag_verify(chunk, asoc))
2248                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2249
2250        /* Make sure that the ERROR chunk has a valid length.
2251         * The parameter walking depends on this as well.
2252         */
2253        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
2254                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2255                                                  commands);
2256
2257        /* Process the error here */
2258        /* FUTURE FIXME:  When PR-SCTP related and other optional
2259         * parms are emitted, this will have to change to handle multiple
2260         * errors.
2261         */
2262        sctp_walk_errors(err, chunk->chunk_hdr) {
2263                if (SCTP_ERROR_STALE_COOKIE == err->cause)
2264                        return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2265                                                        arg, commands);
2266        }
2267
2268        /* It is possible to have malformed error causes, and that
2269         * will cause us to end the walk early.  However, since
2270         * we are discarding the packet, there should be no adverse
2271         * affects.
2272         */
2273        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2274}
2275
2276/*
2277 * Handle a Stale COOKIE Error
2278 *
2279 * Section: 5.2.6 Handle Stale COOKIE Error
2280 * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2281 * one of the following three alternatives.
2282 * ...
2283 * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2284 *    Preservative parameter requesting an extension to the lifetime of
2285 *    the State Cookie. When calculating the time extension, an
2286 *    implementation SHOULD use the RTT information measured based on the
2287 *    previous COOKIE ECHO / ERROR exchange, and should add no more
2288 *    than 1 second beyond the measured RTT, due to long State Cookie
2289 *    lifetimes making the endpoint more subject to a replay attack.
2290 *
2291 * Verification Tag:  Not explicit, but safe to ignore.
2292 *
2293 * Inputs
2294 * (endpoint, asoc, chunk)
2295 *
2296 * Outputs
2297 * (asoc, reply_msg, msg_up, timers, counters)
2298 *
2299 * The return value is the disposition of the chunk.
2300 */
2301static sctp_disposition_t sctp_sf_do_5_2_6_stale(struct net *net,
2302                                                 const struct sctp_endpoint *ep,
2303                                                 const struct sctp_association *asoc,
2304                                                 const sctp_subtype_t type,
2305                                                 void *arg,
2306                                                 sctp_cmd_seq_t *commands)
2307{
2308        struct sctp_chunk *chunk = arg;
2309        time_t stale;
2310        sctp_cookie_preserve_param_t bht;
2311        sctp_errhdr_t *err;
2312        struct sctp_chunk *reply;
2313        struct sctp_bind_addr *bp;
2314        int attempts = asoc->init_err_counter + 1;
2315
2316        if (attempts > asoc->max_init_attempts) {
2317                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2318                                SCTP_ERROR(ETIMEDOUT));
2319                sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2320                                SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2321                return SCTP_DISPOSITION_DELETE_TCB;
2322        }
2323
2324        err = (sctp_errhdr_t *)(chunk->skb->data);
2325
2326        /* When calculating the time extension, an implementation
2327         * SHOULD use the RTT information measured based on the
2328         * previous COOKIE ECHO / ERROR exchange, and should add no
2329         * more than 1 second beyond the measured RTT, due to long
2330         * State Cookie lifetimes making the endpoint more subject to
2331         * a replay attack.
2332         * Measure of Staleness's unit is usec. (1/1000000 sec)
2333         * Suggested Cookie Life-span Increment's unit is msec.
2334         * (1/1000 sec)
2335         * In general, if you use the suggested cookie life, the value
2336         * found in the field of measure of staleness should be doubled
2337         * to give ample time to retransmit the new cookie and thus
2338         * yield a higher probability of success on the reattempt.
2339         */
2340        stale = ntohl(*(__be32 *)((u8 *)err + sizeof(sctp_errhdr_t)));
2341        stale = (stale * 2) / 1000;
2342
2343        bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2344        bht.param_hdr.length = htons(sizeof(bht));
2345        bht.lifespan_increment = htonl(stale);
2346
2347        /* Build that new INIT chunk.  */
2348        bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2349        reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2350        if (!reply)
2351                goto nomem;
2352
2353        sctp_addto_chunk(reply, sizeof(bht), &bht);
2354
2355        /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2356        sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2357
2358        /* Stop pending T3-rtx and heartbeat timers */
2359        sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2360        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2361
2362        /* Delete non-primary peer ip addresses since we are transitioning
2363         * back to the COOKIE-WAIT state
2364         */
2365        sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2366
2367        /* If we've sent any data bundled with COOKIE-ECHO we will need to
2368         * resend
2369         */
2370        sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2371                        SCTP_TRANSPORT(asoc->peer.primary_path));
2372
2373        /* Cast away the const modifier, as we want to just
2374         * rerun it through as a sideffect.
2375         */
2376        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2377
2378        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2379                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2380        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2381                        SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2382        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2383                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2384
2385        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2386
2387        return SCTP_DISPOSITION_CONSUME;
2388
2389nomem:
2390        return SCTP_DISPOSITION_NOMEM;
2391}
2392
2393/*
2394 * Process an ABORT.
2395 *
2396 * Section: 9.1
2397 * After checking the Verification Tag, the receiving endpoint shall
2398 * remove the association from its record, and shall report the
2399 * termination to its upper layer.
2400 *
2401 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2402 * B) Rules for packet carrying ABORT:
2403 *
2404 *  - The endpoint shall always fill in the Verification Tag field of the
2405 *    outbound packet with the destination endpoint's tag value if it
2406 *    is known.
2407 *
2408 *  - If the ABORT is sent in response to an OOTB packet, the endpoint
2409 *    MUST follow the procedure described in Section 8.4.
2410 *
2411 *  - The receiver MUST accept the packet if the Verification Tag
2412 *    matches either its own tag, OR the tag of its peer. Otherwise, the
2413 *    receiver MUST silently discard the packet and take no further
2414 *    action.
2415 *
2416 * Inputs
2417 * (endpoint, asoc, chunk)
2418 *
2419 * Outputs
2420 * (asoc, reply_msg, msg_up, timers, counters)
2421 *
2422 * The return value is the disposition of the chunk.
2423 */
2424sctp_disposition_t sctp_sf_do_9_1_abort(struct net *net,
2425                                        const struct sctp_endpoint *ep,
2426                                        const struct sctp_association *asoc,
2427                                        const sctp_subtype_t type,
2428                                        void *arg,
2429                                        sctp_cmd_seq_t *commands)
2430{
2431        struct sctp_chunk *chunk = arg;
2432
2433        if (!sctp_vtag_verify_either(chunk, asoc))
2434                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2435
2436        /* Make sure that the ABORT chunk has a valid length.
2437         * Since this is an ABORT chunk, we have to discard it
2438         * because of the following text:
2439         * RFC 2960, Section 3.3.7
2440         *    If an endpoint receives an ABORT with a format error or for an
2441         *    association that doesn't exist, it MUST silently discard it.
2442         * Because the length is "invalid", we can't really discard just
2443         * as we do not know its true length.  So, to be safe, discard the
2444         * packet.
2445         */
2446        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2447                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2448
2449        /* ADD-IP: Special case for ABORT chunks
2450         * F4)  One special consideration is that ABORT Chunks arriving
2451         * destined to the IP address being deleted MUST be
2452         * ignored (see Section 5.3.1 for further details).
2453         */
2454        if (SCTP_ADDR_DEL ==
2455                    sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2456                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
2457
2458        return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2459}
2460
2461static sctp_disposition_t __sctp_sf_do_9_1_abort(struct net *net,
2462                                        const struct sctp_endpoint *ep,
2463                                        const struct sctp_association *asoc,
2464                                        const sctp_subtype_t type,
2465                                        void *arg,
2466                                        sctp_cmd_seq_t *commands)
2467{
2468        struct sctp_chunk *chunk = arg;
2469        unsigned int len;
2470        __be16 error = SCTP_ERROR_NO_ERROR;
2471
2472        /* See if we have an error cause code in the chunk.  */
2473        len = ntohs(chunk->chunk_hdr->length);
2474        if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) {
2475
2476                sctp_errhdr_t *err;
2477                sctp_walk_errors(err, chunk->chunk_hdr);
2478                if ((void *)err != (void *)chunk->chunk_end)
2479                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2480
2481                error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2482        }
2483
2484        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2485        /* ASSOC_FAILED will DELETE_TCB. */
2486        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2487        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2488        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2489
2490        return SCTP_DISPOSITION_ABORT;
2491}
2492
2493/*
2494 * Process an ABORT.  (COOKIE-WAIT state)
2495 *
2496 * See sctp_sf_do_9_1_abort() above.
2497 */
2498sctp_disposition_t sctp_sf_cookie_wait_abort(struct net *net,
2499                                     const struct sctp_endpoint *ep,
2500                                     const struct sctp_association *asoc,
2501                                     const sctp_subtype_t type,
2502                                     void *arg,
2503                                     sctp_cmd_seq_t *commands)
2504{
2505        struct sctp_chunk *chunk = arg;
2506        unsigned int len;
2507        __be16 error = SCTP_ERROR_NO_ERROR;
2508
2509        if (!sctp_vtag_verify_either(chunk, asoc))
2510                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2511
2512        /* Make sure that the ABORT chunk has a valid length.
2513         * Since this is an ABORT chunk, we have to discard it
2514         * because of the following text:
2515         * RFC 2960, Section 3.3.7
2516         *    If an endpoint receives an ABORT with a format error or for an
2517         *    association that doesn't exist, it MUST silently discard it.
2518         * Because the length is "invalid", we can't really discard just
2519         * as we do not know its true length.  So, to be safe, discard the
2520         * packet.
2521         */
2522        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_abort_chunk_t)))
2523                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2524
2525        /* See if we have an error cause code in the chunk.  */
2526        len = ntohs(chunk->chunk_hdr->length);
2527        if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2528                error = ((sctp_errhdr_t *)chunk->skb->data)->cause;
2529
2530        return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2531                                      chunk->transport);
2532}
2533
2534/*
2535 * Process an incoming ICMP as an ABORT.  (COOKIE-WAIT state)
2536 */
2537sctp_disposition_t sctp_sf_cookie_wait_icmp_abort(struct net *net,
2538                                        const struct sctp_endpoint *ep,
2539                                        const struct sctp_association *asoc,
2540                                        const sctp_subtype_t type,
2541                                        void *arg,
2542                                        sctp_cmd_seq_t *commands)
2543{
2544        return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2545                                      ENOPROTOOPT, asoc,
2546                                      (struct sctp_transport *)arg);
2547}
2548
2549/*
2550 * Process an ABORT.  (COOKIE-ECHOED state)
2551 */
2552sctp_disposition_t sctp_sf_cookie_echoed_abort(struct net *net,
2553                                               const struct sctp_endpoint *ep,
2554                                               const struct sctp_association *asoc,
2555                                               const sctp_subtype_t type,
2556                                               void *arg,
2557                                               sctp_cmd_seq_t *commands)
2558{
2559        /* There is a single T1 timer, so we should be able to use
2560         * common function with the COOKIE-WAIT state.
2561         */
2562        return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2563}
2564
2565/*
2566 * Stop T1 timer and abort association with "INIT failed".
2567 *
2568 * This is common code called by several sctp_sf_*_abort() functions above.
2569 */
2570static sctp_disposition_t sctp_stop_t1_and_abort(struct net *net,
2571                                           sctp_cmd_seq_t *commands,
2572                                           __be16 error, int sk_err,
2573                                           const struct sctp_association *asoc,
2574                                           struct sctp_transport *transport)
2575{
2576        pr_debug("%s: ABORT received (INIT)\n", __func__);
2577
2578        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2579                        SCTP_STATE(SCTP_STATE_CLOSED));
2580        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2581        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2582                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2583        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2584        /* CMD_INIT_FAILED will DELETE_TCB. */
2585        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2586                        SCTP_PERR(error));
2587
2588        return SCTP_DISPOSITION_ABORT;
2589}
2590
2591/*
2592 * sctp_sf_do_9_2_shut
2593 *
2594 * Section: 9.2
2595 * Upon the reception of the SHUTDOWN, the peer endpoint shall
2596 *  - enter the SHUTDOWN-RECEIVED state,
2597 *
2598 *  - stop accepting new data from its SCTP user
2599 *
2600 *  - verify, by checking the Cumulative TSN Ack field of the chunk,
2601 *    that all its outstanding DATA chunks have been received by the
2602 *    SHUTDOWN sender.
2603 *
2604 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2605 * send a SHUTDOWN in response to a ULP request. And should discard
2606 * subsequent SHUTDOWN chunks.
2607 *
2608 * If there are still outstanding DATA chunks left, the SHUTDOWN
2609 * receiver shall continue to follow normal data transmission
2610 * procedures defined in Section 6 until all outstanding DATA chunks
2611 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2612 * new data from its SCTP user.
2613 *
2614 * Verification Tag:  8.5 Verification Tag [Normal verification]
2615 *
2616 * Inputs
2617 * (endpoint, asoc, chunk)
2618 *
2619 * Outputs
2620 * (asoc, reply_msg, msg_up, timers, counters)
2621 *
2622 * The return value is the disposition of the chunk.
2623 */
2624sctp_disposition_t sctp_sf_do_9_2_shutdown(struct net *net,
2625                                           const struct sctp_endpoint *ep,
2626                                           const struct sctp_association *asoc,
2627                                           const sctp_subtype_t type,
2628                                           void *arg,
2629                                           sctp_cmd_seq_t *commands)
2630{
2631        struct sctp_chunk *chunk = arg;
2632        sctp_shutdownhdr_t *sdh;
2633        sctp_disposition_t disposition;
2634        struct sctp_ulpevent *ev;
2635        __u32 ctsn;
2636
2637        if (!sctp_vtag_verify(chunk, asoc))
2638                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2639
2640        /* Make sure that the SHUTDOWN chunk has a valid length. */
2641        if (!sctp_chunk_length_valid(chunk,
2642                                      sizeof(struct sctp_shutdown_chunk_t)))
2643                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2644                                                  commands);
2645
2646        /* Convert the elaborate header.  */
2647        sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2648        skb_pull(chunk->skb, sizeof(sctp_shutdownhdr_t));
2649        chunk->subh.shutdown_hdr = sdh;
2650        ctsn = ntohl(sdh->cum_tsn_ack);
2651
2652        if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2653                pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2654                         asoc->ctsn_ack_point);
2655
2656                return SCTP_DISPOSITION_DISCARD;
2657        }
2658
2659        /* If Cumulative TSN Ack beyond the max tsn currently
2660         * send, terminating the association and respond to the
2661         * sender with an ABORT.
2662         */
2663        if (!TSN_lt(ctsn, asoc->next_tsn))
2664                return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2665
2666        /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2667         * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2668         * inform the application that it should cease sending data.
2669         */
2670        ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2671        if (!ev) {
2672                disposition = SCTP_DISPOSITION_NOMEM;
2673                goto out;
2674        }
2675        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2676
2677        /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2678         *  - enter the SHUTDOWN-RECEIVED state,
2679         *  - stop accepting new data from its SCTP user
2680         *
2681         * [This is implicit in the new state.]
2682         */
2683        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2684                        SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2685        disposition = SCTP_DISPOSITION_CONSUME;
2686
2687        if (sctp_outq_is_empty(&asoc->outqueue)) {
2688                disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2689                                                          arg, commands);
2690        }
2691
2692        if (SCTP_DISPOSITION_NOMEM == disposition)
2693                goto out;
2694
2695        /*  - verify, by checking the Cumulative TSN Ack field of the
2696         *    chunk, that all its outstanding DATA chunks have been
2697         *    received by the SHUTDOWN sender.
2698         */
2699        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2700                        SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2701
2702out:
2703        return disposition;
2704}
2705
2706/*
2707 * sctp_sf_do_9_2_shut_ctsn
2708 *
2709 * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2710 * it MUST NOT send a SHUTDOWN in response to a ULP request.
2711 * The Cumulative TSN Ack of the received SHUTDOWN chunk
2712 * MUST be processed.
2713 */
2714sctp_disposition_t sctp_sf_do_9_2_shut_ctsn(struct net *net,
2715                                           const struct sctp_endpoint *ep,
2716                                           const struct sctp_association *asoc,
2717                                           const sctp_subtype_t type,
2718                                           void *arg,
2719                                           sctp_cmd_seq_t *commands)
2720{
2721        struct sctp_chunk *chunk = arg;
2722        sctp_shutdownhdr_t *sdh;
2723        __u32 ctsn;
2724
2725        if (!sctp_vtag_verify(chunk, asoc))
2726                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2727
2728        /* Make sure that the SHUTDOWN chunk has a valid length. */
2729        if (!sctp_chunk_length_valid(chunk,
2730                                      sizeof(struct sctp_shutdown_chunk_t)))
2731                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2732                                                  commands);
2733
2734        sdh = (sctp_shutdownhdr_t *)chunk->skb->data;
2735        ctsn = ntohl(sdh->cum_tsn_ack);
2736
2737        if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2738                pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2739                         asoc->ctsn_ack_point);
2740
2741                return SCTP_DISPOSITION_DISCARD;
2742        }
2743
2744        /* If Cumulative TSN Ack beyond the max tsn currently
2745         * send, terminating the association and respond to the
2746         * sender with an ABORT.
2747         */
2748        if (!TSN_lt(ctsn, asoc->next_tsn))
2749                return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2750
2751        /* verify, by checking the Cumulative TSN Ack field of the
2752         * chunk, that all its outstanding DATA chunks have been
2753         * received by the SHUTDOWN sender.
2754         */
2755        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2756                        SCTP_BE32(sdh->cum_tsn_ack));
2757
2758        return SCTP_DISPOSITION_CONSUME;
2759}
2760
2761/* RFC 2960 9.2
2762 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2763 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2764 * transport addresses (either in the IP addresses or in the INIT chunk)
2765 * that belong to this association, it should discard the INIT chunk and
2766 * retransmit the SHUTDOWN ACK chunk.
2767 */
2768sctp_disposition_t sctp_sf_do_9_2_reshutack(struct net *net,
2769                                    const struct sctp_endpoint *ep,
2770                                    const struct sctp_association *asoc,
2771                                    const sctp_subtype_t type,
2772                                    void *arg,
2773                                    sctp_cmd_seq_t *commands)
2774{
2775        struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
2776        struct sctp_chunk *reply;
2777
2778        /* Make sure that the chunk has a valid length */
2779        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
2780                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2781                                                  commands);
2782
2783        /* Since we are not going to really process this INIT, there
2784         * is no point in verifying chunk boundries.  Just generate
2785         * the SHUTDOWN ACK.
2786         */
2787        reply = sctp_make_shutdown_ack(asoc, chunk);
2788        if (NULL == reply)
2789                goto nomem;
2790
2791        /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
2792         * the T2-SHUTDOWN timer.
2793         */
2794        sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
2795
2796        /* and restart the T2-shutdown timer. */
2797        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2798                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2799
2800        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2801
2802        return SCTP_DISPOSITION_CONSUME;
2803nomem:
2804        return SCTP_DISPOSITION_NOMEM;
2805}
2806
2807/*
2808 * sctp_sf_do_ecn_cwr
2809 *
2810 * Section:  Appendix A: Explicit Congestion Notification
2811 *
2812 * CWR:
2813 *
2814 * RFC 2481 details a specific bit for a sender to send in the header of
2815 * its next outbound TCP segment to indicate to its peer that it has
2816 * reduced its congestion window.  This is termed the CWR bit.  For
2817 * SCTP the same indication is made by including the CWR chunk.
2818 * This chunk contains one data element, i.e. the TSN number that
2819 * was sent in the ECNE chunk.  This element represents the lowest
2820 * TSN number in the datagram that was originally marked with the
2821 * CE bit.
2822 *
2823 * Verification Tag: 8.5 Verification Tag [Normal verification]
2824 * Inputs
2825 * (endpoint, asoc, chunk)
2826 *
2827 * Outputs
2828 * (asoc, reply_msg, msg_up, timers, counters)
2829 *
2830 * The return value is the disposition of the chunk.
2831 */
2832sctp_disposition_t sctp_sf_do_ecn_cwr(struct net *net,
2833                                      const struct sctp_endpoint *ep,
2834                                      const struct sctp_association *asoc,
2835                                      const sctp_subtype_t type,
2836                                      void *arg,
2837                                      sctp_cmd_seq_t *commands)
2838{
2839        sctp_cwrhdr_t *cwr;
2840        struct sctp_chunk *chunk = arg;
2841        u32 lowest_tsn;
2842
2843        if (!sctp_vtag_verify(chunk, asoc))
2844                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2845
2846        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2847                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2848                                                  commands);
2849
2850        cwr = (sctp_cwrhdr_t *) chunk->skb->data;
2851        skb_pull(chunk->skb, sizeof(sctp_cwrhdr_t));
2852
2853        lowest_tsn = ntohl(cwr->lowest_tsn);
2854
2855        /* Does this CWR ack the last sent congestion notification? */
2856        if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
2857                /* Stop sending ECNE. */
2858                sctp_add_cmd_sf(commands,
2859                                SCTP_CMD_ECN_CWR,
2860                                SCTP_U32(lowest_tsn));
2861        }
2862        return SCTP_DISPOSITION_CONSUME;
2863}
2864
2865/*
2866 * sctp_sf_do_ecne
2867 *
2868 * Section:  Appendix A: Explicit Congestion Notification
2869 *
2870 * ECN-Echo
2871 *
2872 * RFC 2481 details a specific bit for a receiver to send back in its
2873 * TCP acknowledgements to notify the sender of the Congestion
2874 * Experienced (CE) bit having arrived from the network.  For SCTP this
2875 * same indication is made by including the ECNE chunk.  This chunk
2876 * contains one data element, i.e. the lowest TSN associated with the IP
2877 * datagram marked with the CE bit.....
2878 *
2879 * Verification Tag: 8.5 Verification Tag [Normal verification]
2880 * Inputs
2881 * (endpoint, asoc, chunk)
2882 *
2883 * Outputs
2884 * (asoc, reply_msg, msg_up, timers, counters)
2885 *
2886 * The return value is the disposition of the chunk.
2887 */
2888sctp_disposition_t sctp_sf_do_ecne(struct net *net,
2889                                   const struct sctp_endpoint *ep,
2890                                   const struct sctp_association *asoc,
2891                                   const sctp_subtype_t type,
2892                                   void *arg,
2893                                   sctp_cmd_seq_t *commands)
2894{
2895        sctp_ecnehdr_t *ecne;
2896        struct sctp_chunk *chunk = arg;
2897
2898        if (!sctp_vtag_verify(chunk, asoc))
2899                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2900
2901        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_ecne_chunk_t)))
2902                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2903                                                  commands);
2904
2905        ecne = (sctp_ecnehdr_t *) chunk->skb->data;
2906        skb_pull(chunk->skb, sizeof(sctp_ecnehdr_t));
2907
2908        /* If this is a newer ECNE than the last CWR packet we sent out */
2909        sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
2910                        SCTP_U32(ntohl(ecne->lowest_tsn)));
2911
2912        return SCTP_DISPOSITION_CONSUME;
2913}
2914
2915/*
2916 * Section: 6.2  Acknowledgement on Reception of DATA Chunks
2917 *
2918 * The SCTP endpoint MUST always acknowledge the reception of each valid
2919 * DATA chunk.
2920 *
2921 * The guidelines on delayed acknowledgement algorithm specified in
2922 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
2923 * acknowledgement SHOULD be generated for at least every second packet
2924 * (not every second DATA chunk) received, and SHOULD be generated within
2925 * 200 ms of the arrival of any unacknowledged DATA chunk. In some
2926 * situations it may be beneficial for an SCTP transmitter to be more
2927 * conservative than the algorithms detailed in this document allow.
2928 * However, an SCTP transmitter MUST NOT be more aggressive than the
2929 * following algorithms allow.
2930 *
2931 * A SCTP receiver MUST NOT generate more than one SACK for every
2932 * incoming packet, other than to update the offered window as the
2933 * receiving application consumes new data.
2934 *
2935 * Verification Tag:  8.5 Verification Tag [Normal verification]
2936 *
2937 * Inputs
2938 * (endpoint, asoc, chunk)
2939 *
2940 * Outputs
2941 * (asoc, reply_msg, msg_up, timers, counters)
2942 *
2943 * The return value is the disposition of the chunk.
2944 */
2945sctp_disposition_t sctp_sf_eat_data_6_2(struct net *net,
2946                                        const struct sctp_endpoint *ep,
2947                                        const struct sctp_association *asoc,
2948                                        const sctp_subtype_t type,
2949                                        void *arg,
2950                                        sctp_cmd_seq_t *commands)
2951{
2952        struct sctp_chunk *chunk = arg;
2953        sctp_arg_t force = SCTP_NOFORCE();
2954        int error;
2955
2956        if (!sctp_vtag_verify(chunk, asoc)) {
2957                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
2958                                SCTP_NULL());
2959                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2960        }
2961
2962        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
2963                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2964                                                  commands);
2965
2966        error = sctp_eat_data(asoc, chunk, commands);
2967        switch (error) {
2968        case SCTP_IERROR_NO_ERROR:
2969                break;
2970        case SCTP_IERROR_HIGH_TSN:
2971        case SCTP_IERROR_BAD_STREAM:
2972                SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2973                goto discard_noforce;
2974        case SCTP_IERROR_DUP_TSN:
2975        case SCTP_IERROR_IGNORE_TSN:
2976                SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
2977                goto discard_force;
2978        case SCTP_IERROR_NO_DATA:
2979                goto consume;
2980        case SCTP_IERROR_PROTO_VIOLATION:
2981                return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
2982                        (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
2983        default:
2984                BUG();
2985        }
2986
2987        if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
2988                force = SCTP_FORCE();
2989
2990        if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
2991                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
2992                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
2993        }
2994
2995        /* If this is the last chunk in a packet, we need to count it
2996         * toward sack generation.  Note that we need to SACK every
2997         * OTHER packet containing data chunks, EVEN IF WE DISCARD
2998         * THEM.  We elect to NOT generate SACK's if the chunk fails
2999         * the verification tag test.
3000         *
3001         * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3002         *
3003         * The SCTP endpoint MUST always acknowledge the reception of
3004         * each valid DATA chunk.
3005         *
3006         * The guidelines on delayed acknowledgement algorithm
3007         * specified in  Section 4.2 of [RFC2581] SHOULD be followed.
3008         * Specifically, an acknowledgement SHOULD be generated for at
3009         * least every second packet (not every second DATA chunk)
3010         * received, and SHOULD be generated within 200 ms of the
3011         * arrival of any unacknowledged DATA chunk.  In some
3012         * situations it may be beneficial for an SCTP transmitter to
3013         * be more conservative than the algorithms detailed in this
3014         * document allow. However, an SCTP transmitter MUST NOT be
3015         * more aggressive than the following algorithms allow.
3016         */
3017        if (chunk->end_of_packet)
3018                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3019
3020        return SCTP_DISPOSITION_CONSUME;
3021
3022discard_force:
3023        /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3024         *
3025         * When a packet arrives with duplicate DATA chunk(s) and with
3026         * no new DATA chunk(s), the endpoint MUST immediately send a
3027         * SACK with no delay.  If a packet arrives with duplicate
3028         * DATA chunk(s) bundled with new DATA chunks, the endpoint
3029         * MAY immediately send a SACK.  Normally receipt of duplicate
3030         * DATA chunks will occur when the original SACK chunk was lost
3031         * and the peer's RTO has expired.  The duplicate TSN number(s)
3032         * SHOULD be reported in the SACK as duplicate.
3033         */
3034        /* In our case, we split the MAY SACK advice up whether or not
3035         * the last chunk is a duplicate.'
3036         */
3037        if (chunk->end_of_packet)
3038                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3039        return SCTP_DISPOSITION_DISCARD;
3040
3041discard_noforce:
3042        if (chunk->end_of_packet)
3043                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3044
3045        return SCTP_DISPOSITION_DISCARD;
3046consume:
3047        return SCTP_DISPOSITION_CONSUME;
3048
3049}
3050
3051/*
3052 * sctp_sf_eat_data_fast_4_4
3053 *
3054 * Section: 4 (4)
3055 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3056 *    DATA chunks without delay.
3057 *
3058 * Verification Tag:  8.5 Verification Tag [Normal verification]
3059 * Inputs
3060 * (endpoint, asoc, chunk)
3061 *
3062 * Outputs
3063 * (asoc, reply_msg, msg_up, timers, counters)
3064 *
3065 * The return value is the disposition of the chunk.
3066 */
3067sctp_disposition_t sctp_sf_eat_data_fast_4_4(struct net *net,
3068                                     const struct sctp_endpoint *ep,
3069                                     const struct sctp_association *asoc,
3070                                     const sctp_subtype_t type,
3071                                     void *arg,
3072                                     sctp_cmd_seq_t *commands)
3073{
3074        struct sctp_chunk *chunk = arg;
3075        int error;
3076
3077        if (!sctp_vtag_verify(chunk, asoc)) {
3078                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3079                                SCTP_NULL());
3080                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3081        }
3082
3083        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_data_chunk_t)))
3084                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3085                                                  commands);
3086
3087        error = sctp_eat_data(asoc, chunk, commands);
3088        switch (error) {
3089        case SCTP_IERROR_NO_ERROR:
3090        case SCTP_IERROR_HIGH_TSN:
3091        case SCTP_IERROR_DUP_TSN:
3092        case SCTP_IERROR_IGNORE_TSN:
3093        case SCTP_IERROR_BAD_STREAM:
3094                break;
3095        case SCTP_IERROR_NO_DATA:
3096                goto consume;
3097        case SCTP_IERROR_PROTO_VIOLATION:
3098                return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3099                        (u8 *)chunk->subh.data_hdr, sizeof(sctp_datahdr_t));
3100        default:
3101                BUG();
3102        }
3103
3104        /* Go a head and force a SACK, since we are shutting down. */
3105
3106        /* Implementor's Guide.
3107         *
3108         * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3109         * respond to each received packet containing one or more DATA chunk(s)
3110         * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3111         */
3112        if (chunk->end_of_packet) {
3113                /* We must delay the chunk creation since the cumulative
3114                 * TSN has not been updated yet.
3115                 */
3116                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3117                sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3118                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3119                                SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3120        }
3121
3122consume:
3123        return SCTP_DISPOSITION_CONSUME;
3124}
3125
3126/*
3127 * Section: 6.2  Processing a Received SACK
3128 * D) Any time a SACK arrives, the endpoint performs the following:
3129 *
3130 *     i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3131 *     then drop the SACK.   Since Cumulative TSN Ack is monotonically
3132 *     increasing, a SACK whose Cumulative TSN Ack is less than the
3133 *     Cumulative TSN Ack Point indicates an out-of-order SACK.
3134 *
3135 *     ii) Set rwnd equal to the newly received a_rwnd minus the number
3136 *     of bytes still outstanding after processing the Cumulative TSN Ack
3137 *     and the Gap Ack Blocks.
3138 *
3139 *     iii) If the SACK is missing a TSN that was previously
3140 *     acknowledged via a Gap Ack Block (e.g., the data receiver
3141 *     reneged on the data), then mark the corresponding DATA chunk
3142 *     as available for retransmit:  Mark it as missing for fast
3143 *     retransmit as described in Section 7.2.4 and if no retransmit
3144 *     timer is running for the destination address to which the DATA
3145 *     chunk was originally transmitted, then T3-rtx is started for
3146 *     that destination address.
3147 *
3148 * Verification Tag:  8.5 Verification Tag [Normal verification]
3149 *
3150 * Inputs
3151 * (endpoint, asoc, chunk)
3152 *
3153 * Outputs
3154 * (asoc, reply_msg, msg_up, timers, counters)
3155 *
3156 * The return value is the disposition of the chunk.
3157 */
3158sctp_disposition_t sctp_sf_eat_sack_6_2(struct net *net,
3159                                        const struct sctp_endpoint *ep,
3160                                        const struct sctp_association *asoc,
3161                                        const sctp_subtype_t type,
3162                                        void *arg,
3163                                        sctp_cmd_seq_t *commands)
3164{
3165        struct sctp_chunk *chunk = arg;
3166        sctp_sackhdr_t *sackh;
3167        __u32 ctsn;
3168
3169        if (!sctp_vtag_verify(chunk, asoc))
3170                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3171
3172        /* Make sure that the SACK chunk has a valid length. */
3173        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_sack_chunk_t)))
3174                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3175                                                  commands);
3176
3177        /* Pull the SACK chunk from the data buffer */
3178        sackh = sctp_sm_pull_sack(chunk);
3179        /* Was this a bogus SACK? */
3180        if (!sackh)
3181                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3182        chunk->subh.sack_hdr = sackh;
3183        ctsn = ntohl(sackh->cum_tsn_ack);
3184
3185        /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3186         *     Ack Point, then drop the SACK.  Since Cumulative TSN
3187         *     Ack is monotonically increasing, a SACK whose
3188         *     Cumulative TSN Ack is less than the Cumulative TSN Ack
3189         *     Point indicates an out-of-order SACK.
3190         */
3191        if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3192                pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3193                         asoc->ctsn_ack_point);
3194
3195                return SCTP_DISPOSITION_DISCARD;
3196        }
3197
3198        /* If Cumulative TSN Ack beyond the max tsn currently
3199         * send, terminating the association and respond to the
3200         * sender with an ABORT.
3201         */
3202        if (!TSN_lt(ctsn, asoc->next_tsn))
3203                return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3204
3205        /* Return this SACK for further processing.  */
3206        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3207
3208        /* Note: We do the rest of the work on the PROCESS_SACK
3209         * sideeffect.
3210         */
3211        return SCTP_DISPOSITION_CONSUME;
3212}
3213
3214/*
3215 * Generate an ABORT in response to a packet.
3216 *
3217 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3218 *
3219 * 8) The receiver should respond to the sender of the OOTB packet with
3220 *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
3221 *    MUST fill in the Verification Tag field of the outbound packet
3222 *    with the value found in the Verification Tag field of the OOTB
3223 *    packet and set the T-bit in the Chunk Flags to indicate that the
3224 *    Verification Tag is reflected.  After sending this ABORT, the
3225 *    receiver of the OOTB packet shall discard the OOTB packet and take
3226 *    no further action.
3227 *
3228 * Verification Tag:
3229 *
3230 * The return value is the disposition of the chunk.
3231*/
3232static sctp_disposition_t sctp_sf_tabort_8_4_8(struct net *net,
3233                                        const struct sctp_endpoint *ep,
3234                                        const struct sctp_association *asoc,
3235                                        const sctp_subtype_t type,
3236                                        void *arg,
3237                                        sctp_cmd_seq_t *commands)
3238{
3239        struct sctp_packet *packet = NULL;
3240        struct sctp_chunk *chunk = arg;
3241        struct sctp_chunk *abort;
3242
3243        packet = sctp_ootb_pkt_new(net, asoc, chunk);
3244
3245        if (packet) {
3246                /* Make an ABORT. The T bit will be set if the asoc
3247                 * is NULL.
3248                 */
3249                abort = sctp_make_abort(asoc, chunk, 0);
3250                if (!abort) {
3251                        sctp_ootb_pkt_free(packet);
3252                        return SCTP_DISPOSITION_NOMEM;
3253                }
3254
3255                /* Reflect vtag if T-Bit is set */
3256                if (sctp_test_T_bit(abort))
3257                        packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3258
3259                /* Set the skb to the belonging sock for accounting.  */
3260                abort->skb->sk = ep->base.sk;
3261
3262                sctp_packet_append_chunk(packet, abort);
3263
3264                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3265                                SCTP_PACKET(packet));
3266
3267                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3268
3269                sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3270                return SCTP_DISPOSITION_CONSUME;
3271        }
3272
3273        return SCTP_DISPOSITION_NOMEM;
3274}
3275
3276/*
3277 * Received an ERROR chunk from peer.  Generate SCTP_REMOTE_ERROR
3278 * event as ULP notification for each cause included in the chunk.
3279 *
3280 * API 5.3.1.3 - SCTP_REMOTE_ERROR
3281 *
3282 * The return value is the disposition of the chunk.
3283*/
3284sctp_disposition_t sctp_sf_operr_notify(struct net *net,
3285                                        const struct sctp_endpoint *ep,
3286                                        const struct sctp_association *asoc,
3287                                        const sctp_subtype_t type,
3288                                        void *arg,
3289                                        sctp_cmd_seq_t *commands)
3290{
3291        struct sctp_chunk *chunk = arg;
3292        sctp_errhdr_t *err;
3293
3294        if (!sctp_vtag_verify(chunk, asoc))
3295                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3296
3297        /* Make sure that the ERROR chunk has a valid length. */
3298        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_operr_chunk_t)))
3299                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3300                                                  commands);
3301        sctp_walk_errors(err, chunk->chunk_hdr);
3302        if ((void *)err != (void *)chunk->chunk_end)
3303                return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3304                                                  (void *)err, commands);
3305
3306        sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3307                        SCTP_CHUNK(chunk));
3308
3309        return SCTP_DISPOSITION_CONSUME;
3310}
3311
3312/*
3313 * Process an inbound SHUTDOWN ACK.
3314 *
3315 * From Section 9.2:
3316 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3317 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3318 * peer, and remove all record of the association.
3319 *
3320 * The return value is the disposition.
3321 */
3322sctp_disposition_t sctp_sf_do_9_2_final(struct net *net,
3323                                        const struct sctp_endpoint *ep,
3324                                        const struct sctp_association *asoc,
3325                                        const sctp_subtype_t type,
3326                                        void *arg,
3327                                        sctp_cmd_seq_t *commands)
3328{
3329        struct sctp_chunk *chunk = arg;
3330        struct sctp_chunk *reply;
3331        struct sctp_ulpevent *ev;
3332
3333        if (!sctp_vtag_verify(chunk, asoc))
3334                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3335
3336        /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3337        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3338                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3339                                                  commands);
3340        /* 10.2 H) SHUTDOWN COMPLETE notification
3341         *
3342         * When SCTP completes the shutdown procedures (section 9.2) this
3343         * notification is passed to the upper layer.
3344         */
3345        ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3346                                             0, 0, 0, NULL, GFP_ATOMIC);
3347        if (!ev)
3348                goto nomem;
3349
3350        /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3351        reply = sctp_make_shutdown_complete(asoc, chunk);
3352        if (!reply)
3353                goto nomem_chunk;
3354
3355        /* Do all the commands now (after allocation), so that we
3356         * have consistent state if memory allocation failes
3357         */
3358        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3359
3360        /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3361         * stop the T2-shutdown timer,
3362         */
3363        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3364                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3365
3366        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3367                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3368
3369        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3370                        SCTP_STATE(SCTP_STATE_CLOSED));
3371        SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3372        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3373        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3374
3375        /* ...and remove all record of the association. */
3376        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3377        return SCTP_DISPOSITION_DELETE_TCB;
3378
3379nomem_chunk:
3380        sctp_ulpevent_free(ev);
3381nomem:
3382        return SCTP_DISPOSITION_NOMEM;
3383}
3384
3385/*
3386 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3387 *
3388 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3389 *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3390 *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3391 *    packet must fill in the Verification Tag field of the outbound
3392 *    packet with the Verification Tag received in the SHUTDOWN ACK and
3393 *    set the T-bit in the Chunk Flags to indicate that the Verification
3394 *    Tag is reflected.
3395 *
3396 * 8) The receiver should respond to the sender of the OOTB packet with
3397 *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
3398 *    MUST fill in the Verification Tag field of the outbound packet
3399 *    with the value found in the Verification Tag field of the OOTB
3400 *    packet and set the T-bit in the Chunk Flags to indicate that the
3401 *    Verification Tag is reflected.  After sending this ABORT, the
3402 *    receiver of the OOTB packet shall discard the OOTB packet and take
3403 *    no further action.
3404 */
3405sctp_disposition_t sctp_sf_ootb(struct net *net,
3406                                const struct sctp_endpoint *ep,
3407                                const struct sctp_association *asoc,
3408                                const sctp_subtype_t type,
3409                                void *arg,
3410                                sctp_cmd_seq_t *commands)
3411{
3412        struct sctp_chunk *chunk = arg;
3413        struct sk_buff *skb = chunk->skb;
3414        sctp_chunkhdr_t *ch;
3415        sctp_errhdr_t *err;
3416        __u8 *ch_end;
3417        int ootb_shut_ack = 0;
3418        int ootb_cookie_ack = 0;
3419
3420        SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3421
3422        ch = (sctp_chunkhdr_t *) chunk->chunk_hdr;
3423        do {
3424                /* Report violation if the chunk is less then minimal */
3425                if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
3426                        return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3427                                                  commands);
3428
3429                /* Report violation if chunk len overflows */
3430                ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
3431                if (ch_end > skb_tail_pointer(skb))
3432                        return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3433                                                  commands);
3434
3435                /* Now that we know we at least have a chunk header,
3436                 * do things that are type appropriate.
3437                 */
3438                if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3439                        ootb_shut_ack = 1;
3440
3441                /* RFC 2960, Section 3.3.7
3442                 *   Moreover, under any circumstances, an endpoint that
3443                 *   receives an ABORT  MUST NOT respond to that ABORT by
3444                 *   sending an ABORT of its own.
3445                 */
3446                if (SCTP_CID_ABORT == ch->type)
3447                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3448
3449                /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3450                 * or a COOKIE ACK the SCTP Packet should be silently
3451                 * discarded.
3452                 */
3453
3454                if (SCTP_CID_COOKIE_ACK == ch->type)
3455                        ootb_cookie_ack = 1;
3456
3457                if (SCTP_CID_ERROR == ch->type) {
3458                        sctp_walk_errors(err, ch) {
3459                                if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3460                                        ootb_cookie_ack = 1;
3461                                        break;
3462                                }
3463                        }
3464                }
3465
3466                ch = (sctp_chunkhdr_t *) ch_end;
3467        } while (ch_end < skb_tail_pointer(skb));
3468
3469        if (ootb_shut_ack)
3470                return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3471        else if (ootb_cookie_ack)
3472                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3473        else
3474                return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3475}
3476
3477/*
3478 * Handle an "Out of the blue" SHUTDOWN ACK.
3479 *
3480 * Section: 8.4 5, sctpimpguide 2.41.
3481 *
3482 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3483 *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3484 *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3485 *    packet must fill in the Verification Tag field of the outbound
3486 *    packet with the Verification Tag received in the SHUTDOWN ACK and
3487 *    set the T-bit in the Chunk Flags to indicate that the Verification
3488 *    Tag is reflected.
3489 *
3490 * Inputs
3491 * (endpoint, asoc, type, arg, commands)
3492 *
3493 * Outputs
3494 * (sctp_disposition_t)
3495 *
3496 * The return value is the disposition of the chunk.
3497 */
3498static sctp_disposition_t sctp_sf_shut_8_4_5(struct net *net,
3499                                             const struct sctp_endpoint *ep,
3500                                             const struct sctp_association *asoc,
3501                                             const sctp_subtype_t type,
3502                                             void *arg,
3503                                             sctp_cmd_seq_t *commands)
3504{
3505        struct sctp_packet *packet = NULL;
3506        struct sctp_chunk *chunk = arg;
3507        struct sctp_chunk *shut;
3508
3509        packet = sctp_ootb_pkt_new(net, asoc, chunk);
3510
3511        if (packet) {
3512                /* Make an SHUTDOWN_COMPLETE.
3513                 * The T bit will be set if the asoc is NULL.
3514                 */
3515                shut = sctp_make_shutdown_complete(asoc, chunk);
3516                if (!shut) {
3517                        sctp_ootb_pkt_free(packet);
3518                        return SCTP_DISPOSITION_NOMEM;
3519                }
3520
3521                /* Reflect vtag if T-Bit is set */
3522                if (sctp_test_T_bit(shut))
3523                        packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3524
3525                /* Set the skb to the belonging sock for accounting.  */
3526                shut->skb->sk = ep->base.sk;
3527
3528                sctp_packet_append_chunk(packet, shut);
3529
3530                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3531                                SCTP_PACKET(packet));
3532
3533                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3534
3535                /* If the chunk length is invalid, we don't want to process
3536                 * the reset of the packet.
3537                 */
3538                if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3539                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3540
3541                /* We need to discard the rest of the packet to prevent
3542                 * potential bomming attacks from additional bundled chunks.
3543                 * This is documented in SCTP Threats ID.
3544                 */
3545                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3546        }
3547
3548        return SCTP_DISPOSITION_NOMEM;
3549}
3550
3551/*
3552 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3553 *
3554 * Verification Tag:  8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3555 *   If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3556 *   procedures in section 8.4 SHOULD be followed, in other words it
3557 *   should be treated as an Out Of The Blue packet.
3558 *   [This means that we do NOT check the Verification Tag on these
3559 *   chunks. --piggy ]
3560 *
3561 */
3562sctp_disposition_t sctp_sf_do_8_5_1_E_sa(struct net *net,
3563                                      const struct sctp_endpoint *ep,
3564                                      const struct sctp_association *asoc,
3565                                      const sctp_subtype_t type,
3566                                      void *arg,
3567                                      sctp_cmd_seq_t *commands)
3568{
3569        struct sctp_chunk *chunk = arg;
3570
3571        /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3572        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
3573                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3574                                                  commands);
3575
3576        /* Although we do have an association in this case, it corresponds
3577         * to a restarted association. So the packet is treated as an OOTB
3578         * packet and the state function that handles OOTB SHUTDOWN_ACK is
3579         * called with a NULL association.
3580         */
3581        SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3582
3583        return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3584}
3585
3586/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.  */
3587sctp_disposition_t sctp_sf_do_asconf(struct net *net,
3588                                     const struct sctp_endpoint *ep,
3589                                     const struct sctp_association *asoc,
3590                                     const sctp_subtype_t type, void *arg,
3591                                     sctp_cmd_seq_t *commands)
3592{
3593        struct sctp_chunk       *chunk = arg;
3594        struct sctp_chunk       *asconf_ack = NULL;
3595        struct sctp_paramhdr    *err_param = NULL;
3596        sctp_addiphdr_t         *hdr;
3597        __u32                   serial;
3598
3599        if (!sctp_vtag_verify(chunk, asoc)) {
3600                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3601                                SCTP_NULL());
3602                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3603        }
3604
3605        /* ADD-IP: Section 4.1.1
3606         * This chunk MUST be sent in an authenticated way by using
3607         * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3608         * is received unauthenticated it MUST be silently discarded as
3609         * described in [I-D.ietf-tsvwg-sctp-auth].
3610         */
3611        if (!net->sctp.addip_noauth && !chunk->auth)
3612                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
3613
3614        /* Make sure that the ASCONF ADDIP chunk has a valid length.  */
3615        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_addip_chunk_t)))
3616                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3617                                                  commands);
3618
3619        hdr = (sctp_addiphdr_t *)chunk->skb->data;
3620        serial = ntohl(hdr->serial);
3621
3622        /* Verify the ASCONF chunk before processing it. */
3623        if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
3624                return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3625                                                  (void *)err_param, commands);
3626
3627        /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3628         * the endpoint stored in a new association variable
3629         * 'Peer-Serial-Number'.
3630         */
3631        if (serial == asoc->peer.addip_serial + 1) {
3632                /* If this is the first instance of ASCONF in the packet,
3633                 * we can clean our old ASCONF-ACKs.
3634                 */
3635                if (!chunk->has_asconf)
3636                        sctp_assoc_clean_asconf_ack_cache(asoc);
3637
3638                /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3639                 * expected, process the ASCONF as described below and after
3640                 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3641                 * the response packet and cache a copy of it (in the event it
3642                 * later needs to be retransmitted).
3643                 *
3644                 * Essentially, do V1-V5.
3645                 */
3646                asconf_ack = sctp_process_asconf((struct sctp_association *)
3647                                                 asoc, chunk);
3648                if (!asconf_ack)
3649                        return SCTP_DISPOSITION_NOMEM;
3650        } else if (serial < asoc->peer.addip_serial + 1) {
3651                /* ADDIP 5.2 E2)
3652                 * If the value found in the Sequence Number is less than the
3653                 * ('Peer- Sequence-Number' + 1), simply skip to the next
3654                 * ASCONF, and include in the outbound response packet
3655                 * any previously cached ASCONF-ACK response that was
3656                 * sent and saved that matches the Sequence Number of the
3657                 * ASCONF.  Note: It is possible that no cached ASCONF-ACK
3658                 * Chunk exists.  This will occur when an older ASCONF
3659                 * arrives out of order.  In such a case, the receiver
3660                 * should skip the ASCONF Chunk and not include ASCONF-ACK
3661                 * Chunk for that chunk.
3662                 */
3663                asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3664                if (!asconf_ack)
3665                        return SCTP_DISPOSITION_DISCARD;
3666
3667                /* Reset the transport so that we select the correct one
3668                 * this time around.  This is to make sure that we don't
3669                 * accidentally use a stale transport that's been removed.
3670                 */
3671                asconf_ack->transport = NULL;
3672        } else {
3673                /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3674                 * it must be either a stale packet or from an attacker.
3675                 */
3676                return SCTP_DISPOSITION_DISCARD;
3677        }
3678
3679        /* ADDIP 5.2 E6)  The destination address of the SCTP packet
3680         * containing the ASCONF-ACK Chunks MUST be the source address of
3681         * the SCTP packet that held the ASCONF Chunks.
3682         *
3683         * To do this properly, we'll set the destination address of the chunk
3684         * and at the transmit time, will try look up the transport to use.
3685         * Since ASCONFs may be bundled, the correct transport may not be
3686         * created until we process the entire packet, thus this workaround.
3687         */
3688        asconf_ack->dest = chunk->source;
3689        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3690        if (asoc->new_transport) {
3691                sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3692                ((struct sctp_association *)asoc)->new_transport = NULL;
3693        }
3694
3695        return SCTP_DISPOSITION_CONSUME;
3696}
3697
3698/*
3699 * ADDIP Section 4.3 General rules for address manipulation
3700 * When building TLV parameters for the ASCONF Chunk that will add or
3701 * delete IP addresses the D0 to D13 rules should be applied:
3702 */
3703sctp_disposition_t sctp_sf_do_asconf_ack(struct net *net,
3704                                         const struct sctp_endpoint *ep,
3705                                         const struct sctp_association *asoc,
3706                                         const sctp_subtype_t type, void *arg,
3707                                         sctp_cmd_seq_t *commands)
3708{
3709        struct sctp_chunk       *asconf_ack = arg;
3710        struct sctp_chunk       *last_asconf = asoc->addip_last_asconf;
3711        struct sctp_chunk       *abort;
3712        struct sctp_paramhdr    *err_param = NULL;
3713        sctp_addiphdr_t         *addip_hdr;
3714        __u32                   sent_serial, rcvd_serial;
3715
3716        if (!sctp_vtag_verify(asconf_ack, asoc)) {
3717                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3718                                SCTP_NULL());
3719                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3720        }
3721
3722        /* ADD-IP, Section 4.1.2:
3723         * This chunk MUST be sent in an authenticated way by using
3724         * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3725         * is received unauthenticated it MUST be silently discarded as
3726         * described in [I-D.ietf-tsvwg-sctp-auth].
3727         */
3728        if (!net->sctp.addip_noauth && !asconf_ack->auth)
3729                return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
3730
3731        /* Make sure that the ADDIP chunk has a valid length.  */
3732        if (!sctp_chunk_length_valid(asconf_ack, sizeof(sctp_addip_chunk_t)))
3733                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3734                                                  commands);
3735
3736        addip_hdr = (sctp_addiphdr_t *)asconf_ack->skb->data;
3737        rcvd_serial = ntohl(addip_hdr->serial);
3738
3739        /* Verify the ASCONF-ACK chunk before processing it. */
3740        if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
3741                return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3742                           (void *)err_param, commands);
3743
3744        if (last_asconf) {
3745                addip_hdr = (sctp_addiphdr_t *)last_asconf->subh.addip_hdr;
3746                sent_serial = ntohl(addip_hdr->serial);
3747        } else {
3748                sent_serial = asoc->addip_serial - 1;
3749        }
3750
3751        /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
3752         * equal to the next serial number to be used but no ASCONF chunk is
3753         * outstanding the endpoint MUST ABORT the association. Note that a
3754         * sequence number is greater than if it is no more than 2^^31-1
3755         * larger than the current sequence number (using serial arithmetic).
3756         */
3757        if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
3758            !(asoc->addip_last_asconf)) {
3759                abort = sctp_make_abort(asoc, asconf_ack,
3760                                        sizeof(sctp_errhdr_t));
3761                if (abort) {
3762                        sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
3763                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3764                                        SCTP_CHUNK(abort));
3765                }
3766                /* We are going to ABORT, so we might as well stop
3767                 * processing the rest of the chunks in the packet.
3768                 */
3769                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3770                                SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3771                sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3772                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3773                                SCTP_ERROR(ECONNABORTED));
3774                sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3775                                SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3776                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3777                SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3778                return SCTP_DISPOSITION_ABORT;
3779        }
3780
3781        if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
3782                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3783                                SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
3784
3785                if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
3786                                             asconf_ack)) {
3787                        /* Successfully processed ASCONF_ACK.  We can
3788                         * release the next asconf if we have one.
3789                         */
3790                        sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF,
3791                                        SCTP_NULL());
3792                        return SCTP_DISPOSITION_CONSUME;
3793                }
3794
3795                abort = sctp_make_abort(asoc, asconf_ack,
3796                                        sizeof(sctp_errhdr_t));
3797                if (abort) {
3798                        sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
3799                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
3800                                        SCTP_CHUNK(abort));
3801                }
3802                /* We are going to ABORT, so we might as well stop
3803                 * processing the rest of the chunks in the packet.
3804                 */
3805                sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
3806                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
3807                                SCTP_ERROR(ECONNABORTED));
3808                sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
3809                                SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
3810                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
3811                SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3812                return SCTP_DISPOSITION_ABORT;
3813        }
3814
3815        return SCTP_DISPOSITION_DISCARD;
3816}
3817
3818/*
3819 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
3820 *
3821 * When a FORWARD TSN chunk arrives, the data receiver MUST first update
3822 * its cumulative TSN point to the value carried in the FORWARD TSN
3823 * chunk, and then MUST further advance its cumulative TSN point locally
3824 * if possible.
3825 * After the above processing, the data receiver MUST stop reporting any
3826 * missing TSNs earlier than or equal to the new cumulative TSN point.
3827 *
3828 * Verification Tag:  8.5 Verification Tag [Normal verification]
3829 *
3830 * The return value is the disposition of the chunk.
3831 */
3832sctp_disposition_t sctp_sf_eat_fwd_tsn(struct net *net,
3833                                       const struct sctp_endpoint *ep,
3834                                       const struct sctp_association *asoc,
3835                                       const sctp_subtype_t type,
3836                                       void *arg,
3837                                       sctp_cmd_seq_t *commands)
3838{
3839        struct sctp_chunk *chunk = arg;
3840        struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3841        struct sctp_fwdtsn_skip *skip;
3842        __u16 len;
3843        __u32 tsn;
3844
3845        if (!sctp_vtag_verify(chunk, asoc)) {
3846                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3847                                SCTP_NULL());
3848                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3849        }
3850
3851        /* Make sure that the FORWARD_TSN chunk has valid length.  */
3852        if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3853                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3854                                                  commands);
3855
3856        fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3857        chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3858        len = ntohs(chunk->chunk_hdr->length);
3859        len -= sizeof(struct sctp_chunkhdr);
3860        skb_pull(chunk->skb, len);
3861
3862        tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3863        pr_debug("%s: TSN 0x%x\n", __func__, tsn);
3864
3865        /* The TSN is too high--silently discard the chunk and count on it
3866         * getting retransmitted later.
3867         */
3868        if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3869                goto discard_noforce;
3870
3871        /* Silently discard the chunk if stream-id is not valid */
3872        sctp_walk_fwdtsn(skip, chunk) {
3873                if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3874                        goto discard_noforce;
3875        }
3876
3877        sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3878        if (len > sizeof(struct sctp_fwdtsn_hdr))
3879                sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3880                                SCTP_CHUNK(chunk));
3881
3882        /* Count this as receiving DATA. */
3883        if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3884                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3885                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3886        }
3887
3888        /* FIXME: For now send a SACK, but DATA processing may
3889         * send another.
3890         */
3891        sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
3892
3893        return SCTP_DISPOSITION_CONSUME;
3894
3895discard_noforce:
3896        return SCTP_DISPOSITION_DISCARD;
3897}
3898
3899sctp_disposition_t sctp_sf_eat_fwd_tsn_fast(
3900        struct net *net,
3901        const struct sctp_endpoint *ep,
3902        const struct sctp_association *asoc,
3903        const sctp_subtype_t type,
3904        void *arg,
3905        sctp_cmd_seq_t *commands)
3906{
3907        struct sctp_chunk *chunk = arg;
3908        struct sctp_fwdtsn_hdr *fwdtsn_hdr;
3909        struct sctp_fwdtsn_skip *skip;
3910        __u16 len;
3911        __u32 tsn;
3912
3913        if (!sctp_vtag_verify(chunk, asoc)) {
3914                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3915                                SCTP_NULL());
3916                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3917        }
3918
3919        /* Make sure that the FORWARD_TSN chunk has a valid length.  */
3920        if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_fwdtsn_chunk)))
3921                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3922                                                  commands);
3923
3924        fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
3925        chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
3926        len = ntohs(chunk->chunk_hdr->length);
3927        len -= sizeof(struct sctp_chunkhdr);
3928        skb_pull(chunk->skb, len);
3929
3930        tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
3931        pr_debug("%s: TSN 0x%x\n", __func__, tsn);
3932
3933        /* The TSN is too high--silently discard the chunk and count on it
3934         * getting retransmitted later.
3935         */
3936        if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
3937                goto gen_shutdown;
3938
3939        /* Silently discard the chunk if stream-id is not valid */
3940        sctp_walk_fwdtsn(skip, chunk) {
3941                if (ntohs(skip->stream) >= asoc->c.sinit_max_instreams)
3942                        goto gen_shutdown;
3943        }
3944
3945        sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
3946        if (len > sizeof(struct sctp_fwdtsn_hdr))
3947                sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
3948                                SCTP_CHUNK(chunk));
3949
3950        /* Go a head and force a SACK, since we are shutting down. */
3951gen_shutdown:
3952        /* Implementor's Guide.
3953         *
3954         * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3955         * respond to each received packet containing one or more DATA chunk(s)
3956         * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3957         */
3958        sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3959        sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3960        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3961                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3962
3963        return SCTP_DISPOSITION_CONSUME;
3964}
3965
3966/*
3967 * SCTP-AUTH Section 6.3 Receiving authenticated chukns
3968 *
3969 *    The receiver MUST use the HMAC algorithm indicated in the HMAC
3970 *    Identifier field.  If this algorithm was not specified by the
3971 *    receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
3972 *    during association setup, the AUTH chunk and all chunks after it MUST
3973 *    be discarded and an ERROR chunk SHOULD be sent with the error cause
3974 *    defined in Section 4.1.
3975 *
3976 *    If an endpoint with no shared key receives a Shared Key Identifier
3977 *    other than 0, it MUST silently discard all authenticated chunks.  If
3978 *    the endpoint has at least one endpoint pair shared key for the peer,
3979 *    it MUST use the key specified by the Shared Key Identifier if a
3980 *    key has been configured for that Shared Key Identifier.  If no
3981 *    endpoint pair shared key has been configured for that Shared Key
3982 *    Identifier, all authenticated chunks MUST be silently discarded.
3983 *
3984 * Verification Tag:  8.5 Verification Tag [Normal verification]
3985 *
3986 * The return value is the disposition of the chunk.
3987 */
3988static sctp_ierror_t sctp_sf_authenticate(struct net *net,
3989                                    const struct sctp_endpoint *ep,
3990                                    const struct sctp_association *asoc,
3991                                    const sctp_subtype_t type,
3992                                    struct sctp_chunk *chunk)
3993{
3994        struct sctp_authhdr *auth_hdr;
3995        struct sctp_hmac *hmac;
3996        unsigned int sig_len;
3997        __u16 key_id;
3998        __u8 *save_digest;
3999        __u8 *digest;
4000
4001        /* Pull in the auth header, so we can do some more verification */
4002        auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4003        chunk->subh.auth_hdr = auth_hdr;
4004        skb_pull(chunk->skb, sizeof(struct sctp_authhdr));
4005
4006        /* Make sure that we support the HMAC algorithm from the auth
4007         * chunk.
4008         */
4009        if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4010                return SCTP_IERROR_AUTH_BAD_HMAC;
4011
4012        /* Make sure that the provided shared key identifier has been
4013         * configured
4014         */
4015        key_id = ntohs(auth_hdr->shkey_id);
4016        if (key_id != asoc->active_key_id && !sctp_auth_get_shkey(asoc, key_id))
4017                return SCTP_IERROR_AUTH_BAD_KEYID;
4018
4019
4020        /* Make sure that the length of the signature matches what
4021         * we expect.
4022         */
4023        sig_len = ntohs(chunk->chunk_hdr->length) - sizeof(sctp_auth_chunk_t);
4024        hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4025        if (sig_len != hmac->hmac_len)
4026                return SCTP_IERROR_PROTO_VIOLATION;
4027
4028        /* Now that we've done validation checks, we can compute and
4029         * verify the hmac.  The steps involved are:
4030         *  1. Save the digest from the chunk.
4031         *  2. Zero out the digest in the chunk.
4032         *  3. Compute the new digest
4033         *  4. Compare saved and new digests.
4034         */
4035        digest = auth_hdr->hmac;
4036        skb_pull(chunk->skb, sig_len);
4037
4038        save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4039        if (!save_digest)
4040                goto nomem;
4041
4042        memset(digest, 0, sig_len);
4043
4044        sctp_auth_calculate_hmac(asoc, chunk->skb,
4045                                (struct sctp_auth_chunk *)chunk->chunk_hdr,
4046                                GFP_ATOMIC);
4047
4048        /* Discard the packet if the digests do not match */
4049        if (memcmp(save_digest, digest, sig_len)) {
4050                kfree(save_digest);
4051                return SCTP_IERROR_BAD_SIG;
4052        }
4053
4054        kfree(save_digest);
4055        chunk->auth = 1;
4056
4057        return SCTP_IERROR_NO_ERROR;
4058nomem:
4059        return SCTP_IERROR_NOMEM;
4060}
4061
4062sctp_disposition_t sctp_sf_eat_auth(struct net *net,
4063                                    const struct sctp_endpoint *ep,
4064                                    const struct sctp_association *asoc,
4065                                    const sctp_subtype_t type,
4066                                    void *arg,
4067                                    sctp_cmd_seq_t *commands)
4068{
4069        struct sctp_authhdr *auth_hdr;
4070        struct sctp_chunk *chunk = arg;
4071        struct sctp_chunk *err_chunk;
4072        sctp_ierror_t error;
4073
4074        /* Make sure that the peer has AUTH capable */
4075        if (!asoc->peer.auth_capable)
4076                return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4077
4078        if (!sctp_vtag_verify(chunk, asoc)) {
4079                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4080                                SCTP_NULL());
4081                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4082        }
4083
4084        /* Make sure that the AUTH chunk has valid length.  */
4085        if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4086                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4087                                                  commands);
4088
4089        auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4090        error = sctp_sf_authenticate(net, ep, asoc, type, chunk);
4091        switch (error) {
4092        case SCTP_IERROR_AUTH_BAD_HMAC:
4093                /* Generate the ERROR chunk and discard the rest
4094                 * of the packet
4095                 */
4096                err_chunk = sctp_make_op_error(asoc, chunk,
4097                                               SCTP_ERROR_UNSUP_HMAC,
4098                                               &auth_hdr->hmac_id,
4099                                               sizeof(__u16), 0);
4100                if (err_chunk) {
4101                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4102                                        SCTP_CHUNK(err_chunk));
4103                }
4104                /* Fall Through */
4105        case SCTP_IERROR_AUTH_BAD_KEYID:
4106        case SCTP_IERROR_BAD_SIG:
4107                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4108
4109        case SCTP_IERROR_PROTO_VIOLATION:
4110                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4111                                                  commands);
4112
4113        case SCTP_IERROR_NOMEM:
4114                return SCTP_DISPOSITION_NOMEM;
4115
4116        default:                        /* Prevent gcc warnings */
4117                break;
4118        }
4119
4120        if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4121                struct sctp_ulpevent *ev;
4122
4123                ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4124                                    SCTP_AUTH_NEWKEY, GFP_ATOMIC);
4125
4126                if (!ev)
4127                        return -ENOMEM;
4128
4129                sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4130                                SCTP_ULPEVENT(ev));
4131        }
4132
4133        return SCTP_DISPOSITION_CONSUME;
4134}
4135
4136/*
4137 * Process an unknown chunk.
4138 *
4139 * Section: 3.2. Also, 2.1 in the implementor's guide.
4140 *
4141 * Chunk Types are encoded such that the highest-order two bits specify
4142 * the action that must be taken if the processing endpoint does not
4143 * recognize the Chunk Type.
4144 *
4145 * 00 - Stop processing this SCTP packet and discard it, do not process
4146 *      any further chunks within it.
4147 *
4148 * 01 - Stop processing this SCTP packet and discard it, do not process
4149 *      any further chunks within it, and report the unrecognized
4150 *      chunk in an 'Unrecognized Chunk Type'.
4151 *
4152 * 10 - Skip this chunk and continue processing.
4153 *
4154 * 11 - Skip this chunk and continue processing, but report in an ERROR
4155 *      Chunk using the 'Unrecognized Chunk Type' cause of error.
4156 *
4157 * The return value is the disposition of the chunk.
4158 */
4159sctp_disposition_t sctp_sf_unk_chunk(struct net *net,
4160                                     const struct sctp_endpoint *ep,
4161                                     const struct sctp_association *asoc,
4162                                     const sctp_subtype_t type,
4163                                     void *arg,
4164                                     sctp_cmd_seq_t *commands)
4165{
4166        struct sctp_chunk *unk_chunk = arg;
4167        struct sctp_chunk *err_chunk;
4168        sctp_chunkhdr_t *hdr;
4169
4170        pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4171
4172        if (!sctp_vtag_verify(unk_chunk, asoc))
4173                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4174
4175        /* Make sure that the chunk has a valid length.
4176         * Since we don't know the chunk type, we use a general
4177         * chunkhdr structure to make a comparison.
4178         */
4179        if (!sctp_chunk_length_valid(unk_chunk, sizeof(sctp_chunkhdr_t)))
4180                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4181                                                  commands);
4182
4183        switch (type.chunk & SCTP_CID_ACTION_MASK) {
4184        case SCTP_CID_ACTION_DISCARD:
4185                /* Discard the packet.  */
4186                return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4187        case SCTP_CID_ACTION_DISCARD_ERR:
4188                /* Generate an ERROR chunk as response. */
4189                hdr = unk_chunk->chunk_hdr;
4190                err_chunk = sctp_make_op_error(asoc, unk_chunk,
4191                                               SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4192                                               WORD_ROUND(ntohs(hdr->length)),
4193                                               0);
4194                if (err_chunk) {
4195                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4196                                        SCTP_CHUNK(err_chunk));
4197                }
4198
4199                /* Discard the packet.  */
4200                sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4201                return SCTP_DISPOSITION_CONSUME;
4202        case SCTP_CID_ACTION_SKIP:
4203                /* Skip the chunk.  */
4204                return SCTP_DISPOSITION_DISCARD;
4205        case SCTP_CID_ACTION_SKIP_ERR:
4206                /* Generate an ERROR chunk as response. */
4207                hdr = unk_chunk->chunk_hdr;
4208                err_chunk = sctp_make_op_error(asoc, unk_chunk,
4209                                               SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4210                                               WORD_ROUND(ntohs(hdr->length)),
4211                                               0);
4212                if (err_chunk) {
4213                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4214                                        SCTP_CHUNK(err_chunk));
4215                }
4216                /* Skip the chunk.  */
4217                return SCTP_DISPOSITION_CONSUME;
4218        default:
4219                break;
4220        }
4221
4222        return SCTP_DISPOSITION_DISCARD;
4223}
4224
4225/*
4226 * Discard the chunk.
4227 *
4228 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4229 * [Too numerous to mention...]
4230 * Verification Tag: No verification needed.
4231 * Inputs
4232 * (endpoint, asoc, chunk)
4233 *
4234 * Outputs
4235 * (asoc, reply_msg, msg_up, timers, counters)
4236 *
4237 * The return value is the disposition of the chunk.
4238 */
4239sctp_disposition_t sctp_sf_discard_chunk(struct net *net,
4240                                         const struct sctp_endpoint *ep,
4241                                         const struct sctp_association *asoc,
4242                                         const sctp_subtype_t type,
4243                                         void *arg,
4244                                         sctp_cmd_seq_t *commands)
4245{
4246        struct sctp_chunk *chunk = arg;
4247
4248        /* Make sure that the chunk has a valid length.
4249         * Since we don't know the chunk type, we use a general
4250         * chunkhdr structure to make a comparison.
4251         */
4252        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4253                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4254                                                  commands);
4255
4256        pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4257
4258        return SCTP_DISPOSITION_DISCARD;
4259}
4260
4261/*
4262 * Discard the whole packet.
4263 *
4264 * Section: 8.4 2)
4265 *
4266 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4267 *    silently discard the OOTB packet and take no further action.
4268 *
4269 * Verification Tag: No verification necessary
4270 *
4271 * Inputs
4272 * (endpoint, asoc, chunk)
4273 *
4274 * Outputs
4275 * (asoc, reply_msg, msg_up, timers, counters)
4276 *
4277 * The return value is the disposition of the chunk.
4278 */
4279sctp_disposition_t sctp_sf_pdiscard(struct net *net,
4280                                    const struct sctp_endpoint *ep,
4281                                    const struct sctp_association *asoc,
4282                                    const sctp_subtype_t type,
4283                                    void *arg,
4284                                    sctp_cmd_seq_t *commands)
4285{
4286        SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4287        sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4288
4289        return SCTP_DISPOSITION_CONSUME;
4290}
4291
4292
4293/*
4294 * The other end is violating protocol.
4295 *
4296 * Section: Not specified
4297 * Verification Tag: Not specified
4298 * Inputs
4299 * (endpoint, asoc, chunk)
4300 *
4301 * Outputs
4302 * (asoc, reply_msg, msg_up, timers, counters)
4303 *
4304 * We simply tag the chunk as a violation.  The state machine will log
4305 * the violation and continue.
4306 */
4307sctp_disposition_t sctp_sf_violation(struct net *net,
4308                                     const struct sctp_endpoint *ep,
4309                                     const struct sctp_association *asoc,
4310                                     const sctp_subtype_t type,
4311                                     void *arg,
4312                                     sctp_cmd_seq_t *commands)
4313{
4314        struct sctp_chunk *chunk = arg;
4315
4316        /* Make sure that the chunk has a valid length. */
4317        if (!sctp_chunk_length_valid(chunk, sizeof(sctp_chunkhdr_t)))
4318                return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4319                                                  commands);
4320
4321        return SCTP_DISPOSITION_VIOLATION;
4322}
4323
4324/*
4325 * Common function to handle a protocol violation.
4326 */
4327static sctp_disposition_t sctp_sf_abort_violation(
4328                                     struct net *net,
4329                                     const struct sctp_endpoint *ep,
4330                                     const struct sctp_association *asoc,
4331                                     void *arg,
4332                                     sctp_cmd_seq_t *commands,
4333                                     const __u8 *payload,
4334                                     const size_t paylen)
4335{
4336        struct sctp_packet *packet = NULL;
4337        struct sctp_chunk *chunk =  arg;
4338        struct sctp_chunk *abort = NULL;
4339
4340        /* SCTP-AUTH, Section 6.3:
4341         *    It should be noted that if the receiver wants to tear
4342         *    down an association in an authenticated way only, the
4343         *    handling of malformed packets should not result in
4344         *    tearing down the association.
4345         *
4346         * This means that if we only want to abort associations
4347         * in an authenticated way (i.e AUTH+ABORT), then we
4348         * can't destroy this association just because the packet
4349         * was malformed.
4350         */
4351        if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4352                goto discard;
4353
4354        /* Make the abort chunk. */
4355        abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4356        if (!abort)
4357                goto nomem;
4358
4359        if (asoc) {
4360                /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4361                if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4362                    !asoc->peer.i.init_tag) {
4363                        sctp_initack_chunk_t *initack;
4364
4365                        initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
4366                        if (!sctp_chunk_length_valid(chunk,
4367                                                     sizeof(sctp_initack_chunk_t)))
4368                                abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4369                        else {
4370                                unsigned int inittag;
4371
4372                                inittag = ntohl(initack->init_hdr.init_tag);
4373                                sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4374                                                SCTP_U32(inittag));
4375                        }
4376                }
4377
4378                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4379                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4380
4381                if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4382                        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4383                                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4384                        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4385                                        SCTP_ERROR(ECONNREFUSED));
4386                        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4387                                        SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4388                } else {
4389                        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4390                                        SCTP_ERROR(ECONNABORTED));
4391                        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4392                                        SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4393                        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4394                }
4395        } else {
4396                packet = sctp_ootb_pkt_new(net, asoc, chunk);
4397
4398                if (!packet)
4399                        goto nomem_pkt;
4400
4401                if (sctp_test_T_bit(abort))
4402                        packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4403
4404                abort->skb->sk = ep->base.sk;
4405
4406                sctp_packet_append_chunk(packet, abort);
4407
4408                sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4409                        SCTP_PACKET(packet));
4410
4411                SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4412        }
4413
4414        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4415
4416discard:
4417        sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4418        return SCTP_DISPOSITION_ABORT;
4419
4420nomem_pkt:
4421        sctp_chunk_free(abort);
4422nomem:
4423        return SCTP_DISPOSITION_NOMEM;
4424}
4425
4426/*
4427 * Handle a protocol violation when the chunk length is invalid.
4428 * "Invalid" length is identified as smaller than the minimal length a
4429 * given chunk can be.  For example, a SACK chunk has invalid length
4430 * if its length is set to be smaller than the size of sctp_sack_chunk_t.
4431 *
4432 * We inform the other end by sending an ABORT with a Protocol Violation
4433 * error code.
4434 *
4435 * Section: Not specified
4436 * Verification Tag:  Nothing to do
4437 * Inputs
4438 * (endpoint, asoc, chunk)
4439 *
4440 * Outputs
4441 * (reply_msg, msg_up, counters)
4442 *
4443 * Generate an  ABORT chunk and terminate the association.
4444 */
4445static sctp_disposition_t sctp_sf_violation_chunklen(
4446                                     struct net *net,
4447                                     const struct sctp_endpoint *ep,
4448                                     const struct sctp_association *asoc,
4449                                     const sctp_subtype_t type,
4450                                     void *arg,
4451                                     sctp_cmd_seq_t *commands)
4452{
4453        static const char err_str[] = "The following chunk had invalid length:";
4454
4455        return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4456                                        sizeof(err_str));
4457}
4458
4459/*
4460 * Handle a protocol violation when the parameter length is invalid.
4461 * If the length is smaller than the minimum length of a given parameter,
4462 * or accumulated length in multi parameters exceeds the end of the chunk,
4463 * the length is considered as invalid.
4464 */
4465static sctp_disposition_t sctp_sf_violation_paramlen(
4466                                     struct net *net,
4467                                     const struct sctp_endpoint *ep,
4468                                     const struct sctp_association *asoc,
4469                                     const sctp_subtype_t type,
4470                                     void *arg, void *ext,
4471                                     sctp_cmd_seq_t *commands)
4472{
4473        struct sctp_chunk *chunk =  arg;
4474        struct sctp_paramhdr *param = ext;
4475        struct sctp_chunk *abort = NULL;
4476
4477        if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4478                goto discard;
4479
4480        /* Make the abort chunk. */
4481        abort = sctp_make_violation_paramlen(asoc, chunk, param);
4482        if (!abort)
4483                goto nomem;
4484
4485        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4486        SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4487
4488        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4489                        SCTP_ERROR(ECONNABORTED));
4490        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4491                        SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4492        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4493        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4494
4495discard:
4496        sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4497        return SCTP_DISPOSITION_ABORT;
4498nomem:
4499        return SCTP_DISPOSITION_NOMEM;
4500}
4501
4502/* Handle a protocol violation when the peer trying to advance the
4503 * cumulative tsn ack to a point beyond the max tsn currently sent.
4504 *
4505 * We inform the other end by sending an ABORT with a Protocol Violation
4506 * error code.
4507 */
4508static sctp_disposition_t sctp_sf_violation_ctsn(
4509                                     struct net *net,
4510                                     const struct sctp_endpoint *ep,
4511                                     const struct sctp_association *asoc,
4512                                     const sctp_subtype_t type,
4513                                     void *arg,
4514                                     sctp_cmd_seq_t *commands)
4515{
4516        static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4517
4518        return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4519                                        sizeof(err_str));
4520}
4521
4522/* Handle protocol violation of an invalid chunk bundling.  For example,
4523 * when we have an association and we receive bundled INIT-ACK, or
4524 * SHUDOWN-COMPLETE, our peer is clearly violationg the "MUST NOT bundle"
4525 * statement from the specs.  Additionally, there might be an attacker
4526 * on the path and we may not want to continue this communication.
4527 */
4528static sctp_disposition_t sctp_sf_violation_chunk(
4529                                     struct net *net,
4530                                     const struct sctp_endpoint *ep,
4531                                     const struct sctp_association *asoc,
4532                                     const sctp_subtype_t type,
4533                                     void *arg,
4534                                     sctp_cmd_seq_t *commands)
4535{
4536        static const char err_str[] = "The following chunk violates protocol:";
4537
4538        if (!asoc)
4539                return sctp_sf_violation(net, ep, asoc, type, arg, commands);
4540
4541        return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4542                                        sizeof(err_str));
4543}
4544/***************************************************************************
4545 * These are the state functions for handling primitive (Section 10) events.
4546 ***************************************************************************/
4547/*
4548 * sctp_sf_do_prm_asoc
4549 *
4550 * Section: 10.1 ULP-to-SCTP
4551 * B) Associate
4552 *
4553 * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4554 * outbound stream count)
4555 * -> association id [,destination transport addr list] [,outbound stream
4556 * count]
4557 *
4558 * This primitive allows the upper layer to initiate an association to a
4559 * specific peer endpoint.
4560 *
4561 * The peer endpoint shall be specified by one of the transport addresses
4562 * which defines the endpoint (see Section 1.4).  If the local SCTP
4563 * instance has not been initialized, the ASSOCIATE is considered an
4564 * error.
4565 * [This is not relevant for the kernel implementation since we do all
4566 * initialization at boot time.  It we hadn't initialized we wouldn't
4567 * get anywhere near this code.]
4568 *
4569 * An association id, which is a local handle to the SCTP association,
4570 * will be returned on successful establishment of the association. If
4571 * SCTP is not able to open an SCTP association with the peer endpoint,
4572 * an error is returned.
4573 * [In the kernel implementation, the struct sctp_association needs to
4574 * be created BEFORE causing this primitive to run.]
4575 *
4576 * Other association parameters may be returned, including the
4577 * complete destination transport addresses of the peer as well as the
4578 * outbound stream count of the local endpoint. One of the transport
4579 * address from the returned destination addresses will be selected by
4580 * the local endpoint as default primary path for sending SCTP packets
4581 * to this peer.  The returned "destination transport addr list" can
4582 * be used by the ULP to change the default primary path or to force
4583 * sending a packet to a specific transport address.  [All of this
4584 * stuff happens when the INIT ACK arrives.  This is a NON-BLOCKING
4585 * function.]
4586 *
4587 * Mandatory attributes:
4588 *
4589 * o local SCTP instance name - obtained from the INITIALIZE operation.
4590 *   [This is the argument asoc.]
4591 * o destination transport addr - specified as one of the transport
4592 * addresses of the peer endpoint with which the association is to be
4593 * established.
4594 *  [This is asoc->peer.active_path.]
4595 * o outbound stream count - the number of outbound streams the ULP
4596 * would like to open towards this peer endpoint.
4597 * [BUG: This is not currently implemented.]
4598 * Optional attributes:
4599 *
4600 * None.
4601 *
4602 * The return value is a disposition.
4603 */
4604sctp_disposition_t sctp_sf_do_prm_asoc(struct net *net,
4605                                       const struct sctp_endpoint *ep,
4606                                       const struct sctp_association *asoc,
4607                                       const sctp_subtype_t type,
4608                                       void *arg,
4609                                       sctp_cmd_seq_t *commands)
4610{
4611        struct sctp_chunk *repl;
4612        struct sctp_association *my_asoc;
4613
4614        /* The comment below says that we enter COOKIE-WAIT AFTER
4615         * sending the INIT, but that doesn't actually work in our
4616         * implementation...
4617         */
4618        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4619                        SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4620
4621        /* RFC 2960 5.1 Normal Establishment of an Association
4622         *
4623         * A) "A" first sends an INIT chunk to "Z".  In the INIT, "A"
4624         * must provide its Verification Tag (Tag_A) in the Initiate
4625         * Tag field.  Tag_A SHOULD be a random number in the range of
4626         * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4627         */
4628
4629        repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
4630        if (!repl)
4631                goto nomem;
4632
4633        /* Choose transport for INIT. */
4634        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
4635                        SCTP_CHUNK(repl));
4636
4637        /* Cast away the const modifier, as we want to just
4638         * rerun it through as a sideffect.
4639         */
4640        my_asoc = (struct sctp_association *)asoc;
4641        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
4642
4643        /* After sending the INIT, "A" starts the T1-init timer and
4644         * enters the COOKIE-WAIT state.
4645         */
4646        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
4647                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4648        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
4649        return SCTP_DISPOSITION_CONSUME;
4650
4651nomem:
4652        return SCTP_DISPOSITION_NOMEM;
4653}
4654
4655/*
4656 * Process the SEND primitive.
4657 *
4658 * Section: 10.1 ULP-to-SCTP
4659 * E) Send
4660 *
4661 * Format: SEND(association id, buffer address, byte count [,context]
4662 *         [,stream id] [,life time] [,destination transport address]
4663 *         [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
4664 * -> result
4665 *
4666 * This is the main method to send user data via SCTP.
4667 *
4668 * Mandatory attributes:
4669 *
4670 *  o association id - local handle to the SCTP association
4671 *
4672 *  o buffer address - the location where the user message to be
4673 *    transmitted is stored;
4674 *
4675 *  o byte count - The size of the user data in number of bytes;
4676 *
4677 * Optional attributes:
4678 *
4679 *  o context - an optional 32 bit integer that will be carried in the
4680 *    sending failure notification to the ULP if the transportation of
4681 *    this User Message fails.
4682 *
4683 *  o stream id - to indicate which stream to send the data on. If not
4684 *    specified, stream 0 will be used.
4685 *
4686 *  o life time - specifies the life time of the user data. The user data
4687 *    will not be sent by SCTP after the life time expires. This
4688 *    parameter can be used to avoid efforts to transmit stale
4689 *    user messages. SCTP notifies the ULP if the data cannot be
4690 *    initiated to transport (i.e. sent to the destination via SCTP's
4691 *    send primitive) within the life time variable. However, the
4692 *    user data will be transmitted if SCTP has attempted to transmit a
4693 *    chunk before the life time expired.
4694 *
4695 *  o destination transport address - specified as one of the destination
4696 *    transport addresses of the peer endpoint to which this packet
4697 *    should be sent. Whenever possible, SCTP should use this destination
4698 *    transport address for sending the packets, instead of the current
4699 *    primary path.
4700 *
4701 *  o unorder flag - this flag, if present, indicates that the user
4702 *    would like the data delivered in an unordered fashion to the peer
4703 *    (i.e., the U flag is set to 1 on all DATA chunks carrying this
4704 *    message).
4705 *
4706 *  o no-bundle flag - instructs SCTP not to bundle this user data with
4707 *    other outbound DATA chunks. SCTP MAY still bundle even when
4708 *    this flag is present, when faced with network congestion.
4709 *
4710 *  o payload protocol-id - A 32 bit unsigned integer that is to be
4711 *    passed to the peer indicating the type of payload protocol data
4712 *    being transmitted. This value is passed as opaque data by SCTP.
4713 *
4714 * The return value is the disposition.
4715 */
4716sctp_disposition_t sctp_sf_do_prm_send(struct net *net,
4717                                       const struct sctp_endpoint *ep,
4718                                       const struct sctp_association *asoc,
4719                                       const sctp_subtype_t type,
4720                                       void *arg,
4721                                       sctp_cmd_seq_t *commands)
4722{
4723        struct sctp_datamsg *msg = arg;
4724
4725        sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
4726        return SCTP_DISPOSITION_CONSUME;
4727}
4728
4729/*
4730 * Process the SHUTDOWN primitive.
4731 *
4732 * Section: 10.1:
4733 * C) Shutdown
4734 *
4735 * Format: SHUTDOWN(association id)
4736 * -> result
4737 *
4738 * Gracefully closes an association. Any locally queued user data
4739 * will be delivered to the peer. The association will be terminated only
4740 * after the peer acknowledges all the SCTP packets sent.  A success code
4741 * will be returned on successful termination of the association. If
4742 * attempting to terminate the association results in a failure, an error
4743 * code shall be returned.
4744 *
4745 * Mandatory attributes:
4746 *
4747 *  o association id - local handle to the SCTP association
4748 *
4749 * Optional attributes:
4750 *
4751 * None.
4752 *
4753 * The return value is the disposition.
4754 */
4755sctp_disposition_t sctp_sf_do_9_2_prm_shutdown(
4756        struct net *net,
4757        const struct sctp_endpoint *ep,
4758        const struct sctp_association *asoc,
4759        const sctp_subtype_t type,
4760        void *arg,
4761        sctp_cmd_seq_t *commands)
4762{
4763        int disposition;
4764
4765        /* From 9.2 Shutdown of an Association
4766         * Upon receipt of the SHUTDOWN primitive from its upper
4767         * layer, the endpoint enters SHUTDOWN-PENDING state and
4768         * remains there until all outstanding data has been
4769         * acknowledged by its peer. The endpoint accepts no new data
4770         * from its upper layer, but retransmits data to the far end
4771         * if necessary to fill gaps.
4772         */
4773        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4774                        SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
4775
4776        disposition = SCTP_DISPOSITION_CONSUME;
4777        if (sctp_outq_is_empty(&asoc->outqueue)) {
4778                disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
4779                                                            arg, commands);
4780        }
4781        return disposition;
4782}
4783
4784/*
4785 * Process the ABORT primitive.
4786 *
4787 * Section: 10.1:
4788 * C) Abort
4789 *
4790 * Format: Abort(association id [, cause code])
4791 * -> result
4792 *
4793 * Ungracefully closes an association. Any locally queued user data
4794 * will be discarded and an ABORT chunk is sent to the peer.  A success code
4795 * will be returned on successful abortion of the association. If
4796 * attempting to abort the association results in a failure, an error
4797 * code shall be returned.
4798 *
4799 * Mandatory attributes:
4800 *
4801 *  o association id - local handle to the SCTP association
4802 *
4803 * Optional attributes:
4804 *
4805 *  o cause code - reason of the abort to be passed to the peer
4806 *
4807 * None.
4808 *
4809 * The return value is the disposition.
4810 */
4811sctp_disposition_t sctp_sf_do_9_1_prm_abort(
4812        struct net *net,
4813        const struct sctp_endpoint *ep,
4814        const struct sctp_association *asoc,
4815        const sctp_subtype_t type,
4816        void *arg,
4817        sctp_cmd_seq_t *commands)
4818{
4819        /* From 9.1 Abort of an Association
4820         * Upon receipt of the ABORT primitive from its upper
4821         * layer, the endpoint enters CLOSED state and
4822         * discard all outstanding data has been
4823         * acknowledged by its peer. The endpoint accepts no new data
4824         * from its upper layer, but retransmits data to the far end
4825         * if necessary to fill gaps.
4826         */
4827        struct sctp_chunk *abort = arg;
4828        sctp_disposition_t retval;
4829
4830        retval = SCTP_DISPOSITION_CONSUME;
4831
4832        if (abort)
4833                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4834
4835        /* Even if we can't send the ABORT due to low memory delete the
4836         * TCB.  This is a departure from our typical NOMEM handling.
4837         */
4838
4839        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4840                        SCTP_ERROR(ECONNABORTED));
4841        /* Delete the established association. */
4842        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4843                        SCTP_PERR(SCTP_ERROR_USER_ABORT));
4844
4845        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4846        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4847
4848        return retval;
4849}
4850
4851/* We tried an illegal operation on an association which is closed.  */
4852sctp_disposition_t sctp_sf_error_closed(struct net *net,
4853                                        const struct sctp_endpoint *ep,
4854                                        const struct sctp_association *asoc,
4855                                        const sctp_subtype_t type,
4856                                        void *arg,
4857                                        sctp_cmd_seq_t *commands)
4858{
4859        sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
4860        return SCTP_DISPOSITION_CONSUME;
4861}
4862
4863/* We tried an illegal operation on an association which is shutting
4864 * down.
4865 */
4866sctp_disposition_t sctp_sf_error_shutdown(struct net *net,
4867                                          const struct sctp_endpoint *ep,
4868                                          const struct sctp_association *asoc,
4869                                          const sctp_subtype_t type,
4870                                          void *arg,
4871                                          sctp_cmd_seq_t *commands)
4872{
4873        sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
4874                        SCTP_ERROR(-ESHUTDOWN));
4875        return SCTP_DISPOSITION_CONSUME;
4876}
4877
4878/*
4879 * sctp_cookie_wait_prm_shutdown
4880 *
4881 * Section: 4 Note: 2
4882 * Verification Tag:
4883 * Inputs
4884 * (endpoint, asoc)
4885 *
4886 * The RFC does not explicitly address this issue, but is the route through the
4887 * state table when someone issues a shutdown while in COOKIE_WAIT state.
4888 *
4889 * Outputs
4890 * (timers)
4891 */
4892sctp_disposition_t sctp_sf_cookie_wait_prm_shutdown(
4893        struct net *net,
4894        const struct sctp_endpoint *ep,
4895        const struct sctp_association *asoc,
4896        const sctp_subtype_t type,
4897        void *arg,
4898        sctp_cmd_seq_t *commands)
4899{
4900        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4901                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4902
4903        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4904                        SCTP_STATE(SCTP_STATE_CLOSED));
4905
4906        SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
4907
4908        sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
4909
4910        return SCTP_DISPOSITION_DELETE_TCB;
4911}
4912
4913/*
4914 * sctp_cookie_echoed_prm_shutdown
4915 *
4916 * Section: 4 Note: 2
4917 * Verification Tag:
4918 * Inputs
4919 * (endpoint, asoc)
4920 *
4921 * The RFC does not explcitly address this issue, but is the route through the
4922 * state table when someone issues a shutdown while in COOKIE_ECHOED state.
4923 *
4924 * Outputs
4925 * (timers)
4926 */
4927sctp_disposition_t sctp_sf_cookie_echoed_prm_shutdown(
4928        struct net *net,
4929        const struct sctp_endpoint *ep,
4930        const struct sctp_association *asoc,
4931        const sctp_subtype_t type,
4932        void *arg, sctp_cmd_seq_t *commands)
4933{
4934        /* There is a single T1 timer, so we should be able to use
4935         * common function with the COOKIE-WAIT state.
4936         */
4937        return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
4938}
4939
4940/*
4941 * sctp_sf_cookie_wait_prm_abort
4942 *
4943 * Section: 4 Note: 2
4944 * Verification Tag:
4945 * Inputs
4946 * (endpoint, asoc)
4947 *
4948 * The RFC does not explicitly address this issue, but is the route through the
4949 * state table when someone issues an abort while in COOKIE_WAIT state.
4950 *
4951 * Outputs
4952 * (timers)
4953 */
4954sctp_disposition_t sctp_sf_cookie_wait_prm_abort(
4955        struct net *net,
4956        const struct sctp_endpoint *ep,
4957        const struct sctp_association *asoc,
4958        const sctp_subtype_t type,
4959        void *arg,
4960        sctp_cmd_seq_t *commands)
4961{
4962        struct sctp_chunk *abort = arg;
4963        sctp_disposition_t retval;
4964
4965        /* Stop T1-init timer */
4966        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4967                        SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4968        retval = SCTP_DISPOSITION_CONSUME;
4969
4970        if (abort)
4971                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4972
4973        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4974                        SCTP_STATE(SCTP_STATE_CLOSED));
4975
4976        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4977
4978        /* Even if we can't send the ABORT due to low memory delete the
4979         * TCB.  This is a departure from our typical NOMEM handling.
4980         */
4981
4982        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4983                        SCTP_ERROR(ECONNREFUSED));
4984        /* Delete the established association. */
4985        sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4986                        SCTP_PERR(SCTP_ERROR_USER_ABORT));
4987
4988        return retval;
4989}
4990
4991/*
4992 * sctp_sf_cookie_echoed_prm_abort
4993 *
4994 * Section: 4 Note: 3
4995 * Verification Tag:
4996 * Inputs
4997 * (endpoint, asoc)
4998 *
4999 * The RFC does not explcitly address this issue, but is the route through the
5000 * state table when someone issues an abort while in COOKIE_ECHOED state.
5001 *
5002 * Outputs
5003 * (timers)
5004 */
5005sctp_disposition_t sctp_sf_cookie_echoed_prm_abort(
5006        struct net *net,
5007        const struct sctp_endpoint *ep,
5008        const struct sctp_association *asoc,
5009        const sctp_subtype_t type,
5010        void *arg,
5011        sctp_cmd_seq_t *commands)
5012{
5013        /* There is a single T1 timer, so we should be able to use
5014         * common function with the COOKIE-WAIT state.
5015         */
5016        return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5017}
5018
5019/*
5020 * sctp_sf_shutdown_pending_prm_abort
5021 *
5022 * Inputs
5023 * (endpoint, asoc)
5024 *
5025 * The RFC does not explicitly address this issue, but is the route through the
5026 * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5027 *
5028 * Outputs
5029 * (timers)
5030 */
5031sctp_disposition_t sctp_sf_shutdown_pending_prm_abort(
5032        struct net *net,
5033        const struct sctp_endpoint *ep,
5034        const struct sctp_association *asoc,
5035        const sctp_subtype_t type,
5036        void *arg,
5037        sctp_cmd_seq_t *commands)
5038{
5039        /* Stop the T5-shutdown guard timer.  */
5040        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5041                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5042
5043        return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5044}
5045
5046/*
5047 * sctp_sf_shutdown_sent_prm_abort
5048 *
5049 * Inputs
5050 * (endpoint, asoc)
5051 *
5052 * The RFC does not explicitly address this issue, but is the route through the
5053 * state table when someone issues an abort while in SHUTDOWN-SENT state.
5054 *
5055 * Outputs
5056 * (timers)
5057 */
5058sctp_disposition_t sctp_sf_shutdown_sent_prm_abort(
5059        struct net *net,
5060        const struct sctp_endpoint *ep,
5061        const struct sctp_association *asoc,
5062        const sctp_subtype_t type,
5063        void *arg,
5064        sctp_cmd_seq_t *commands)
5065{
5066        /* Stop the T2-shutdown timer.  */
5067        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5068                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5069
5070        /* Stop the T5-shutdown guard timer.  */
5071        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5072                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5073
5074        return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5075}
5076
5077/*
5078 * sctp_sf_cookie_echoed_prm_abort
5079 *
5080 * Inputs
5081 * (endpoint, asoc)
5082 *
5083 * The RFC does not explcitly address this issue, but is the route through the
5084 * state table when someone issues an abort while in COOKIE_ECHOED state.
5085 *
5086 * Outputs
5087 * (timers)
5088 */
5089sctp_disposition_t sctp_sf_shutdown_ack_sent_prm_abort(
5090        struct net *net,
5091        const struct sctp_endpoint *ep,
5092        const struct sctp_association *asoc,
5093        const sctp_subtype_t type,
5094        void *arg,
5095        sctp_cmd_seq_t *commands)
5096{
5097        /* The same T2 timer, so we should be able to use
5098         * common function with the SHUTDOWN-SENT state.
5099         */
5100        return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5101}
5102
5103/*
5104 * Process the REQUESTHEARTBEAT primitive
5105 *
5106 * 10.1 ULP-to-SCTP
5107 * J) Request Heartbeat
5108 *
5109 * Format: REQUESTHEARTBEAT(association id, destination transport address)
5110 *
5111 * -> result
5112 *
5113 * Instructs the local endpoint to perform a HeartBeat on the specified
5114 * destination transport address of the given association. The returned
5115 * result should indicate whether the transmission of the HEARTBEAT
5116 * chunk to the destination address is successful.
5117 *
5118 * Mandatory attributes:
5119 *
5120 * o association id - local handle to the SCTP association
5121 *
5122 * o destination transport address - the transport address of the
5123 *   association on which a heartbeat should be issued.
5124 */
5125sctp_disposition_t sctp_sf_do_prm_requestheartbeat(
5126                                        struct net *net,
5127                                        const struct sctp_endpoint *ep,
5128                                        const struct sctp_association *asoc,
5129                                        const sctp_subtype_t type,
5130                                        void *arg,
5131                                        sctp_cmd_seq_t *commands)
5132{
5133        if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5134                                      (struct sctp_transport *)arg, commands))
5135                return SCTP_DISPOSITION_NOMEM;
5136
5137        /*
5138         * RFC 2960 (bis), section 8.3
5139         *
5140         *    D) Request an on-demand HEARTBEAT on a specific destination
5141         *    transport address of a given association.
5142         *
5143         *    The endpoint should increment the respective error  counter of
5144         *    the destination transport address each time a HEARTBEAT is sent
5145         *    to that address and not acknowledged within one RTO.
5146         *
5147         */
5148        sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5149                        SCTP_TRANSPORT(arg));
5150        return SCTP_DISPOSITION_CONSUME;
5151}
5152
5153/*
5154 * ADDIP Section 4.1 ASCONF Chunk Procedures
5155 * When an endpoint has an ASCONF signaled change to be sent to the
5156 * remote endpoint it should do A1 to A9
5157 */
5158sctp_disposition_t sctp_sf_do_prm_asconf(struct net *net,
5159                                        const struct sctp_endpoint *ep,
5160                                        const struct sctp_association *asoc,
5161                                        const sctp_subtype_t type,
5162                                        void *arg,
5163                                        sctp_cmd_seq_t *commands)
5164{
5165        struct sctp_chunk *chunk = arg;
5166
5167        sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5168        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5169                        SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5170        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5171        return SCTP_DISPOSITION_CONSUME;
5172}
5173
5174/*
5175 * Ignore the primitive event
5176 *
5177 * The return value is the disposition of the primitive.
5178 */
5179sctp_disposition_t sctp_sf_ignore_primitive(
5180        struct net *net,
5181        const struct sctp_endpoint *ep,
5182        const struct sctp_association *asoc,
5183        const sctp_subtype_t type,
5184        void *arg,
5185        sctp_cmd_seq_t *commands)
5186{
5187        pr_debug("%s: primitive type:%d is ignored\n", __func__,
5188                 type.primitive);
5189
5190        return SCTP_DISPOSITION_DISCARD;
5191}
5192
5193/***************************************************************************
5194 * These are the state functions for the OTHER events.
5195 ***************************************************************************/
5196
5197/*
5198 * When the SCTP stack has no more user data to send or retransmit, this
5199 * notification is given to the user. Also, at the time when a user app
5200 * subscribes to this event, if there is no data to be sent or
5201 * retransmit, the stack will immediately send up this notification.
5202 */
5203sctp_disposition_t sctp_sf_do_no_pending_tsn(
5204        struct net *net,
5205        const struct sctp_endpoint *ep,
5206        const struct sctp_association *asoc,
5207        const sctp_subtype_t type,
5208        void *arg,
5209        sctp_cmd_seq_t *commands)
5210{
5211        struct sctp_ulpevent *event;
5212
5213        event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5214        if (!event)
5215                return SCTP_DISPOSITION_NOMEM;
5216
5217        sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5218
5219        return SCTP_DISPOSITION_CONSUME;
5220}
5221
5222/*
5223 * Start the shutdown negotiation.
5224 *
5225 * From Section 9.2:
5226 * Once all its outstanding data has been acknowledged, the endpoint
5227 * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5228 * TSN Ack field the last sequential TSN it has received from the peer.
5229 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5230 * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5231 * with the updated last sequential TSN received from its peer.
5232 *
5233 * The return value is the disposition.
5234 */
5235sctp_disposition_t sctp_sf_do_9_2_start_shutdown(
5236        struct net *net,
5237        const struct sctp_endpoint *ep,
5238        const struct sctp_association *asoc,
5239        const sctp_subtype_t type,
5240        void *arg,
5241        sctp_cmd_seq_t *commands)
5242{
5243        struct sctp_chunk *reply;
5244
5245        /* Once all its outstanding data has been acknowledged, the
5246         * endpoint shall send a SHUTDOWN chunk to its peer including
5247         * in the Cumulative TSN Ack field the last sequential TSN it
5248         * has received from the peer.
5249         */
5250        reply = sctp_make_shutdown(asoc, NULL);
5251        if (!reply)
5252                goto nomem;
5253
5254        /* Set the transport for the SHUTDOWN chunk and the timeout for the
5255         * T2-shutdown timer.
5256         */
5257        sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5258
5259        /* It shall then start the T2-shutdown timer */
5260        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5261                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5262
5263        /* RFC 4960 Section 9.2
5264         * The sender of the SHUTDOWN MAY also start an overall guard timer
5265         * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5266         */
5267        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5268                        SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5269
5270        if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5271                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5272                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5273
5274        /* and enter the SHUTDOWN-SENT state.  */
5275        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5276                        SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5277
5278        /* sctp-implguide 2.10 Issues with Heartbeating and failover
5279         *
5280         * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5281         * or SHUTDOWN-ACK.
5282         */
5283        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5284
5285        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5286
5287        return SCTP_DISPOSITION_CONSUME;
5288
5289nomem:
5290        return SCTP_DISPOSITION_NOMEM;
5291}
5292
5293/*
5294 * Generate a SHUTDOWN ACK now that everything is SACK'd.
5295 *
5296 * From Section 9.2:
5297 *
5298 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5299 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5300 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5301 * endpoint must re-send the SHUTDOWN ACK.
5302 *
5303 * The return value is the disposition.
5304 */
5305sctp_disposition_t sctp_sf_do_9_2_shutdown_ack(
5306        struct net *net,
5307        const struct sctp_endpoint *ep,
5308        const struct sctp_association *asoc,
5309        const sctp_subtype_t type,
5310        void *arg,
5311        sctp_cmd_seq_t *commands)
5312{
5313        struct sctp_chunk *chunk = (struct sctp_chunk *) arg;
5314        struct sctp_chunk *reply;
5315
5316        /* There are 2 ways of getting here:
5317         *    1) called in response to a SHUTDOWN chunk
5318         *    2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5319         *
5320         * For the case (2), the arg parameter is set to NULL.  We need
5321         * to check that we have a chunk before accessing it's fields.
5322         */
5323        if (chunk) {
5324                if (!sctp_vtag_verify(chunk, asoc))
5325                        return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
5326
5327                /* Make sure that the SHUTDOWN chunk has a valid length. */
5328                if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk_t)))
5329                        return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
5330                                                          commands);
5331        }
5332
5333        /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5334         * shall send a SHUTDOWN ACK ...
5335         */
5336        reply = sctp_make_shutdown_ack(asoc, chunk);
5337        if (!reply)
5338                goto nomem;
5339
5340        /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5341         * the T2-shutdown timer.
5342         */
5343        sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5344
5345        /* and start/restart a T2-shutdown timer of its own, */
5346        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5347                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5348
5349        if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5350                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5351                                SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5352
5353        /* Enter the SHUTDOWN-ACK-SENT state.  */
5354        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5355                        SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5356
5357        /* sctp-implguide 2.10 Issues with Heartbeating and failover
5358         *
5359         * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5360         * or SHUTDOWN-ACK.
5361         */
5362        sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5363
5364        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5365
5366        return SCTP_DISPOSITION_CONSUME;
5367
5368nomem:
5369        return SCTP_DISPOSITION_NOMEM;
5370}
5371
5372/*
5373 * Ignore the event defined as other
5374 *
5375 * The return value is the disposition of the event.
5376 */
5377sctp_disposition_t sctp_sf_ignore_other(struct net *net,
5378                                        const struct sctp_endpoint *ep,
5379                                        const struct sctp_association *asoc,
5380                                        const sctp_subtype_t type,
5381                                        void *arg,
5382                                        sctp_cmd_seq_t *commands)
5383{
5384        pr_debug("%s: the event other type:%d is ignored\n",
5385                 __func__, type.other);
5386
5387        return SCTP_DISPOSITION_DISCARD;
5388}
5389
5390/************************************************************
5391 * These are the state functions for handling timeout events.
5392 ************************************************************/
5393
5394/*
5395 * RTX Timeout
5396 *
5397 * Section: 6.3.3 Handle T3-rtx Expiration
5398 *
5399 * Whenever the retransmission timer T3-rtx expires for a destination
5400 * address, do the following:
5401 * [See below]
5402 *
5403 * The return value is the disposition of the chunk.
5404 */
5405sctp_disposition_t sctp_sf_do_6_3_3_rtx(struct net *net,
5406                                        const struct sctp_endpoint *ep,
5407                                        const struct sctp_association *asoc,
5408                                        const sctp_subtype_t type,
5409                                        void *arg,
5410                                        sctp_cmd_seq_t *commands)
5411{
5412        struct sctp_transport *transport = arg;
5413
5414        SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5415
5416        if (asoc->overall_error_count >= asoc->max_retrans) {
5417                if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5418                        /*
5419                         * We are here likely because the receiver had its rwnd
5420                         * closed for a while and we have not been able to
5421                         * transmit the locally queued data within the maximum
5422                         * retransmission attempts limit.  Start the T5
5423                         * shutdown guard timer to give the receiver one last
5424                         * chance and some additional time to recover before
5425                         * aborting.
5426                         */
5427                        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5428                                SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5429                } else {
5430                        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5431                                        SCTP_ERROR(ETIMEDOUT));
5432                        /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5433                        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5434                                        SCTP_PERR(SCTP_ERROR_NO_ERROR));
5435                        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5436                        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5437                        return SCTP_DISPOSITION_DELETE_TCB;
5438                }
5439        }
5440
5441        /* E1) For the destination address for which the timer
5442         * expires, adjust its ssthresh with rules defined in Section
5443         * 7.2.3 and set the cwnd <- MTU.
5444         */
5445
5446        /* E2) For the destination address for which the timer
5447         * expires, set RTO <- RTO * 2 ("back off the timer").  The
5448         * maximum value discussed in rule C7 above (RTO.max) may be
5449         * used to provide an upper bound to this doubling operation.
5450         */
5451
5452        /* E3) Determine how many of the earliest (i.e., lowest TSN)
5453         * outstanding DATA chunks for the address for which the
5454         * T3-rtx has expired will fit into a single packet, subject
5455         * to the MTU constraint for the path corresponding to the
5456         * destination transport address to which the retransmission
5457         * is being sent (this may be different from the address for
5458         * which the timer expires [see Section 6.4]).  Call this
5459         * value K. Bundle and retransmit those K DATA chunks in a
5460         * single packet to the destination endpoint.
5461         *
5462         * Note: Any DATA chunks that were sent to the address for
5463         * which the T3-rtx timer expired but did not fit in one MTU
5464         * (rule E3 above), should be marked for retransmission and
5465         * sent as soon as cwnd allows (normally when a SACK arrives).
5466         */
5467
5468        /* Do some failure management (Section 8.2). */
5469        sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5470
5471        /* NB: Rules E4 and F1 are implicit in R1.  */
5472        sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5473
5474        return SCTP_DISPOSITION_CONSUME;
5475}
5476
5477/*
5478 * Generate delayed SACK on timeout
5479 *
5480 * Section: 6.2  Acknowledgement on Reception of DATA Chunks
5481 *
5482 * The guidelines on delayed acknowledgement algorithm specified in
5483 * Section 4.2 of [RFC2581] SHOULD be followed.  Specifically, an
5484 * acknowledgement SHOULD be generated for at least every second packet
5485 * (not every second DATA chunk) received, and SHOULD be generated
5486 * within 200 ms of the arrival of any unacknowledged DATA chunk.  In
5487 * some situations it may be beneficial for an SCTP transmitter to be
5488 * more conservative than the algorithms detailed in this document
5489 * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5490 * the following algorithms allow.
5491 */
5492sctp_disposition_t sctp_sf_do_6_2_sack(struct net *net,
5493                                       const struct sctp_endpoint *ep,
5494                                       const struct sctp_association *asoc,
5495                                       const sctp_subtype_t type,
5496                                       void *arg,
5497                                       sctp_cmd_seq_t *commands)
5498{
5499        SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5500        sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5501        return SCTP_DISPOSITION_CONSUME;
5502}
5503
5504/*
5505 * sctp_sf_t1_init_timer_expire
5506 *
5507 * Section: 4 Note: 2
5508 * Verification Tag:
5509 * Inputs
5510 * (endpoint, asoc)
5511 *
5512 *  RFC 2960 Section 4 Notes
5513 *  2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5514 *     and re-start the T1-init timer without changing state.  This MUST
5515 *     be repeated up to 'Max.Init.Retransmits' times.  After that, the
5516 *     endpoint MUST abort the initialization process and report the
5517 *     error to SCTP user.
5518 *
5519 * Outputs
5520 * (timers, events)
5521 *
5522 */
5523sctp_disposition_t sctp_sf_t1_init_timer_expire(struct net *net,
5524                                           const struct sctp_endpoint *ep,
5525                                           const struct sctp_association *asoc,
5526                                           const sctp_subtype_t type,
5527                                           void *arg,
5528                                           sctp_cmd_seq_t *commands)
5529{
5530        struct sctp_chunk *repl = NULL;
5531        struct sctp_bind_addr *bp;
5532        int attempts = asoc->init_err_counter + 1;
5533
5534        pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5535
5536        SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5537
5538        if (attempts <= asoc->max_init_attempts) {
5539                bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5540                repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5541                if (!repl)
5542                        return SCTP_DISPOSITION_NOMEM;
5543
5544                /* Choose transport for INIT. */
5545                sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5546                                SCTP_CHUNK(repl));
5547
5548                /* Issue a sideeffect to do the needed accounting. */
5549                sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5550                                SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5551
5552                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5553        } else {
5554                pr_debug("%s: giving up on INIT, attempts:%d "
5555                         "max_init_attempts:%d\n", __func__, attempts,
5556                         asoc->max_init_attempts);
5557
5558                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5559                                SCTP_ERROR(ETIMEDOUT));
5560                sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5561                                SCTP_PERR(SCTP_ERROR_NO_ERROR));
5562                return SCTP_DISPOSITION_DELETE_TCB;
5563        }
5564
5565        return SCTP_DISPOSITION_CONSUME;
5566}
5567
5568/*
5569 * sctp_sf_t1_cookie_timer_expire
5570 *
5571 * Section: 4 Note: 2
5572 * Verification Tag:
5573 * Inputs
5574 * (endpoint, asoc)
5575 *
5576 *  RFC 2960 Section 4 Notes
5577 *  3) If the T1-cookie timer expires, the endpoint MUST retransmit
5578 *     COOKIE ECHO and re-start the T1-cookie timer without changing
5579 *     state.  This MUST be repeated up to 'Max.Init.Retransmits' times.
5580 *     After that, the endpoint MUST abort the initialization process and
5581 *     report the error to SCTP user.
5582 *
5583 * Outputs
5584 * (timers, events)
5585 *
5586 */
5587sctp_disposition_t sctp_sf_t1_cookie_timer_expire(struct net *net,
5588                                           const struct sctp_endpoint *ep,
5589                                           const struct sctp_association *asoc,
5590                                           const sctp_subtype_t type,
5591                                           void *arg,
5592                                           sctp_cmd_seq_t *commands)
5593{
5594        struct sctp_chunk *repl = NULL;
5595        int attempts = asoc->init_err_counter + 1;
5596
5597        pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5598
5599        SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5600
5601        if (attempts <= asoc->max_init_attempts) {
5602                repl = sctp_make_cookie_echo(asoc, NULL);
5603                if (!repl)
5604                        return SCTP_DISPOSITION_NOMEM;
5605
5606                sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5607                                SCTP_CHUNK(repl));
5608                /* Issue a sideeffect to do the needed accounting. */
5609                sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5610                                SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5611
5612                sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5613        } else {
5614                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5615                                SCTP_ERROR(ETIMEDOUT));
5616                sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5617                                SCTP_PERR(SCTP_ERROR_NO_ERROR));
5618                return SCTP_DISPOSITION_DELETE_TCB;
5619        }
5620
5621        return SCTP_DISPOSITION_CONSUME;
5622}
5623
5624/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
5625 * with the updated last sequential TSN received from its peer.
5626 *
5627 * An endpoint should limit the number of retransmissions of the
5628 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
5629 * If this threshold is exceeded the endpoint should destroy the TCB and
5630 * MUST report the peer endpoint unreachable to the upper layer (and
5631 * thus the association enters the CLOSED state).  The reception of any
5632 * packet from its peer (i.e. as the peer sends all of its queued DATA
5633 * chunks) should clear the endpoint's retransmission count and restart
5634 * the T2-Shutdown timer,  giving its peer ample opportunity to transmit
5635 * all of its queued DATA chunks that have not yet been sent.
5636 */
5637sctp_disposition_t sctp_sf_t2_timer_expire(struct net *net,
5638                                           const struct sctp_endpoint *ep,
5639                                           const struct sctp_association *asoc,
5640                                           const sctp_subtype_t type,
5641                                           void *arg,
5642                                           sctp_cmd_seq_t *commands)
5643{
5644        struct sctp_chunk *reply = NULL;
5645
5646        pr_debug("%s: timer T2 expired\n", __func__);
5647
5648        SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
5649
5650        ((struct sctp_association *)asoc)->shutdown_retries++;
5651
5652        if (asoc->overall_error_count >= asoc->max_retrans) {
5653                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5654                                SCTP_ERROR(ETIMEDOUT));
5655                /* Note:  CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5656                sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5657                                SCTP_PERR(SCTP_ERROR_NO_ERROR));
5658                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5659                SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5660                return SCTP_DISPOSITION_DELETE_TCB;
5661        }
5662
5663        switch (asoc->state) {
5664        case SCTP_STATE_SHUTDOWN_SENT:
5665                reply = sctp_make_shutdown(asoc, NULL);
5666                break;
5667
5668        case SCTP_STATE_SHUTDOWN_ACK_SENT:
5669                reply = sctp_make_shutdown_ack(asoc, NULL);
5670                break;
5671
5672        default:
5673                BUG();
5674                break;
5675        }
5676
5677        if (!reply)
5678                goto nomem;
5679
5680        /* Do some failure management (Section 8.2).
5681         * If we remove the transport an SHUTDOWN was last sent to, don't
5682         * do failure management.
5683         */
5684        if (asoc->shutdown_last_sent_to)
5685                sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5686                                SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
5687
5688        /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
5689         * the T2-shutdown timer.
5690         */
5691        sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5692
5693        /* Restart the T2-shutdown timer.  */
5694        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5695                        SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5696        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5697        return SCTP_DISPOSITION_CONSUME;
5698
5699nomem:
5700        return SCTP_DISPOSITION_NOMEM;
5701}
5702
5703/*
5704 * ADDIP Section 4.1 ASCONF CHunk Procedures
5705 * If the T4 RTO timer expires the endpoint should do B1 to B5
5706 */
5707sctp_disposition_t sctp_sf_t4_timer_expire(
5708        struct net *net,
5709        const struct sctp_endpoint *ep,
5710        const struct sctp_association *asoc,
5711        const sctp_subtype_t type,
5712        void *arg,
5713        sctp_cmd_seq_t *commands)
5714{
5715        struct sctp_chunk *chunk = asoc->addip_last_asconf;
5716        struct sctp_transport *transport = chunk->transport;
5717
5718        SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
5719
5720        /* ADDIP 4.1 B1) Increment the error counters and perform path failure
5721         * detection on the appropriate destination address as defined in
5722         * RFC2960 [5] section 8.1 and 8.2.
5723         */
5724        if (transport)
5725                sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
5726                                SCTP_TRANSPORT(transport));
5727
5728        /* Reconfig T4 timer and transport. */
5729        sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5730
5731        /* ADDIP 4.1 B2) Increment the association error counters and perform
5732         * endpoint failure detection on the association as defined in
5733         * RFC2960 [5] section 8.1 and 8.2.
5734         * association error counter is incremented in SCTP_CMD_STRIKE.
5735         */
5736        if (asoc->overall_error_count >= asoc->max_retrans) {
5737                sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5738                                SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5739                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5740                                SCTP_ERROR(ETIMEDOUT));
5741                sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5742                                SCTP_PERR(SCTP_ERROR_NO_ERROR));
5743                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5744                SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5745                return SCTP_DISPOSITION_ABORT;
5746        }
5747
5748        /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
5749         * the ASCONF chunk was sent by doubling the RTO timer value.
5750         * This is done in SCTP_CMD_STRIKE.
5751         */
5752
5753        /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
5754         * choose an alternate destination address (please refer to RFC2960
5755         * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
5756         * chunk, it MUST be the same (including its serial number) as the last
5757         * ASCONF sent.
5758         */
5759        sctp_chunk_hold(asoc->addip_last_asconf);
5760        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
5761                        SCTP_CHUNK(asoc->addip_last_asconf));
5762
5763        /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
5764         * destination is selected, then the RTO used will be that of the new
5765         * destination address.
5766         */
5767        sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5768                        SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5769
5770        return SCTP_DISPOSITION_CONSUME;
5771}
5772
5773/* sctpimpguide-05 Section 2.12.2
5774 * The sender of the SHUTDOWN MAY also start an overall guard timer
5775 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5776 * At the expiration of this timer the sender SHOULD abort the association
5777 * by sending an ABORT chunk.
5778 */
5779sctp_disposition_t sctp_sf_t5_timer_expire(struct net *net,
5780                                           const struct sctp_endpoint *ep,
5781                                           const struct sctp_association *asoc,
5782                                           const sctp_subtype_t type,
5783                                           void *arg,
5784                                           sctp_cmd_seq_t *commands)
5785{
5786        struct sctp_chunk *reply = NULL;
5787
5788        pr_debug("%s: timer T5 expired\n", __func__);
5789
5790        SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
5791
5792        reply = sctp_make_abort(asoc, NULL, 0);
5793        if (!reply)
5794                goto nomem;
5795
5796        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5797        sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5798                        SCTP_ERROR(ETIMEDOUT));
5799        sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5800                        SCTP_PERR(SCTP_ERROR_NO_ERROR));
5801
5802        SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5803        SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5804
5805        return SCTP_DISPOSITION_DELETE_TCB;
5806nomem:
5807        return SCTP_DISPOSITION_NOMEM;
5808}
5809
5810/* Handle expiration of AUTOCLOSE timer.  When the autoclose timer expires,
5811 * the association is automatically closed by starting the shutdown process.
5812 * The work that needs to be done is same as when SHUTDOWN is initiated by
5813 * the user.  So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
5814 */
5815sctp_disposition_t sctp_sf_autoclose_timer_expire(
5816        struct net *net,
5817        const struct sctp_endpoint *ep,
5818        const struct sctp_association *asoc,
5819        const sctp_subtype_t type,
5820        void *arg,
5821        sctp_cmd_seq_t *commands)
5822{
5823        int disposition;
5824
5825        SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
5826
5827        /* From 9.2 Shutdown of an Association
5828         * Upon receipt of the SHUTDOWN primitive from its upper
5829         * layer, the endpoint enters SHUTDOWN-PENDING state and
5830         * remains there until all outstanding data has been
5831         * acknowledged by its peer. The endpoint accepts no new data
5832         * from its upper layer, but retransmits data to the far end
5833         * if necessary to fill gaps.
5834         */
5835        sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5836                        SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5837
5838        disposition = SCTP_DISPOSITION_CONSUME;
5839        if (sctp_outq_is_empty(&asoc->outqueue)) {
5840                disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
5841                                                            arg, commands);
5842        }
5843        return disposition;
5844}
5845
5846/*****************************************************************************
5847 * These are sa state functions which could apply to all types of events.
5848 ****************************************************************************/
5849
5850/*
5851 * This table entry is not implemented.
5852 *
5853 * Inputs
5854 * (endpoint, asoc, chunk)
5855 *
5856 * The return value is the disposition of the chunk.
5857 */
5858sctp_disposition_t sctp_sf_not_impl(struct net *net,
5859                                    const struct sctp_endpoint *ep,
5860                                    const struct sctp_association *asoc,
5861                                    const sctp_subtype_t type,
5862                                    void *arg,
5863                                    sctp_cmd_seq_t *commands)
5864{
5865        return SCTP_DISPOSITION_NOT_IMPL;
5866}
5867
5868/*
5869 * This table entry represents a bug.
5870 *
5871 * Inputs
5872 * (endpoint, asoc, chunk)
5873 *
5874 * The return value is the disposition of the chunk.
5875 */
5876sctp_disposition_t sctp_sf_bug(struct net *net,
5877                               const struct sctp_endpoint *ep,
5878                               const struct sctp_association *asoc,
5879                               const sctp_subtype_t type,
5880                               void *arg,
5881                               sctp_cmd_seq_t *commands)
5882{
5883        return SCTP_DISPOSITION_BUG;
5884}
5885
5886/*
5887 * This table entry represents the firing of a timer in the wrong state.
5888 * Since timer deletion cannot be guaranteed a timer 'may' end up firing
5889 * when the association is in the wrong state.   This event should
5890 * be ignored, so as to prevent any rearming of the timer.
5891 *
5892 * Inputs
5893 * (endpoint, asoc, chunk)
5894 *
5895 * The return value is the disposition of the chunk.
5896 */
5897sctp_disposition_t sctp_sf_timer_ignore(struct net *net,
5898                                        const struct sctp_endpoint *ep,
5899                                        const struct sctp_association *asoc,
5900                                        const sctp_subtype_t type,
5901                                        void *arg,
5902                                        sctp_cmd_seq_t *commands)
5903{
5904        pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
5905
5906        return SCTP_DISPOSITION_CONSUME;
5907}
5908
5909/********************************************************************
5910 * 2nd Level Abstractions
5911 ********************************************************************/
5912
5913/* Pull the SACK chunk based on the SACK header. */
5914static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
5915{
5916        struct sctp_sackhdr *sack;
5917        unsigned int len;
5918        __u16 num_blocks;
5919        __u16 num_dup_tsns;
5920
5921        /* Protect ourselves from reading too far into
5922         * the skb from a bogus sender.
5923         */
5924        sack = (struct sctp_sackhdr *) chunk->skb->data;
5925
5926        num_blocks = ntohs(sack->num_gap_ack_blocks);
5927        num_dup_tsns = ntohs(sack->num_dup_tsns);
5928        len = sizeof(struct sctp_sackhdr);
5929        len += (num_blocks + num_dup_tsns) * sizeof(__u32);
5930        if (len > chunk->skb->len)
5931                return NULL;
5932
5933        skb_pull(chunk->skb, len);
5934
5935        return sack;
5936}
5937
5938/* Create an ABORT packet to be sent as a response, with the specified
5939 * error causes.
5940 */
5941static struct sctp_packet *sctp_abort_pkt_new(struct net *net,
5942                                  const struct sctp_endpoint *ep,
5943                                  const struct sctp_association *asoc,
5944                                  struct sctp_chunk *chunk,
5945                                  const void *payload,
5946                                  size_t paylen)
5947{
5948        struct sctp_packet *packet;
5949        struct sctp_chunk *abort;
5950
5951        packet = sctp_ootb_pkt_new(net, asoc, chunk);
5952
5953        if (packet) {
5954                /* Make an ABORT.
5955                 * The T bit will be set if the asoc is NULL.
5956                 */
5957                abort = sctp_make_abort(asoc, chunk, paylen);
5958                if (!abort) {
5959                        sctp_ootb_pkt_free(packet);
5960                        return NULL;
5961                }
5962
5963                /* Reflect vtag if T-Bit is set */
5964                if (sctp_test_T_bit(abort))
5965                        packet->vtag = ntohl(chunk->sctp_hdr->vtag);
5966
5967                /* Add specified error causes, i.e., payload, to the
5968                 * end of the chunk.
5969                 */
5970                sctp_addto_chunk(abort, paylen, payload);
5971
5972                /* Set the skb to the belonging sock for accounting.  */
5973                abort->skb->sk = ep->base.sk;
5974
5975                sctp_packet_append_chunk(packet, abort);
5976
5977        }
5978
5979        return packet;
5980}
5981
5982/* Allocate a packet for responding in the OOTB conditions.  */
5983static struct sctp_packet *sctp_ootb_pkt_new(struct net *net,
5984                                             const struct sctp_association *asoc,
5985                                             const struct sctp_chunk *chunk)
5986{
5987        struct sctp_packet *packet;
5988        struct sctp_transport *transport;
5989        __u16 sport;
5990        __u16 dport;
5991        __u32 vtag;
5992
5993        /* Get the source and destination port from the inbound packet.  */
5994        sport = ntohs(chunk->sctp_hdr->dest);
5995        dport = ntohs(chunk->sctp_hdr->source);
5996
5997        /* The V-tag is going to be the same as the inbound packet if no
5998         * association exists, otherwise, use the peer's vtag.
5999         */
6000        if (asoc) {
6001                /* Special case the INIT-ACK as there is no peer's vtag
6002                 * yet.
6003                 */
6004                switch (chunk->chunk_hdr->type) {
6005                case SCTP_CID_INIT_ACK:
6006                {
6007                        sctp_initack_chunk_t *initack;
6008
6009                        initack = (sctp_initack_chunk_t *)chunk->chunk_hdr;
6010                        vtag = ntohl(initack->init_hdr.init_tag);
6011                        break;
6012                }
6013                default:
6014                        vtag = asoc->peer.i.init_tag;
6015                        break;
6016                }
6017        } else {
6018                /* Special case the INIT and stale COOKIE_ECHO as there is no
6019                 * vtag yet.
6020                 */
6021                switch (chunk->chunk_hdr->type) {
6022                case SCTP_CID_INIT:
6023                {
6024                        sctp_init_chunk_t *init;
6025
6026                        init = (sctp_init_chunk_t *)chunk->chunk_hdr;
6027                        vtag = ntohl(init->init_hdr.init_tag);
6028                        break;
6029                }
6030                default:
6031                        vtag = ntohl(chunk->sctp_hdr->vtag);
6032                        break;
6033                }
6034        }
6035
6036        /* Make a transport for the bucket, Eliza... */
6037        transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6038        if (!transport)
6039                goto nomem;
6040
6041        /* Cache a route for the transport with the chunk's destination as
6042         * the source address.
6043         */
6044        sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6045                             sctp_sk(net->sctp.ctl_sock));
6046
6047        packet = sctp_packet_init(&transport->packet, transport, sport, dport);
6048        packet = sctp_packet_config(packet, vtag, 0);
6049
6050        return packet;
6051
6052nomem:
6053        return NULL;
6054}
6055
6056/* Free the packet allocated earlier for responding in the OOTB condition.  */
6057void sctp_ootb_pkt_free(struct sctp_packet *packet)
6058{
6059        sctp_transport_free(packet->transport);
6060}
6061
6062/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found  */
6063static void sctp_send_stale_cookie_err(struct net *net,
6064                                       const struct sctp_endpoint *ep,
6065                                       const struct sctp_association *asoc,
6066                                       const struct sctp_chunk *chunk,
6067                                       sctp_cmd_seq_t *commands,
6068                                       struct sctp_chunk *err_chunk)
6069{
6070        struct sctp_packet *packet;
6071
6072        if (err_chunk) {
6073                packet = sctp_ootb_pkt_new(net, asoc, chunk);
6074                if (packet) {
6075                        struct sctp_signed_cookie *cookie;
6076
6077                        /* Override the OOTB vtag from the cookie. */
6078                        cookie = chunk->subh.cookie_hdr;
6079                        packet->vtag = cookie->c.peer_vtag;
6080
6081                        /* Set the skb to the belonging sock for accounting. */
6082                        err_chunk->skb->sk = ep->base.sk;
6083                        sctp_packet_append_chunk(packet, err_chunk);
6084                        sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6085                                        SCTP_PACKET(packet));
6086                        SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6087                } else
6088                        sctp_chunk_free (err_chunk);
6089        }
6090}
6091
6092
6093/* Process a data chunk */
6094static int sctp_eat_data(const struct sctp_association *asoc,
6095                         struct sctp_chunk *chunk,
6096                         sctp_cmd_seq_t *commands)
6097{
6098        sctp_datahdr_t *data_hdr;
6099        struct sctp_chunk *err;
6100        size_t datalen;
6101        sctp_verb_t deliver;
6102        int tmp;
6103        __u32 tsn;
6104        struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6105        struct sock *sk = asoc->base.sk;
6106        struct net *net = sock_net(sk);
6107        u16 ssn;
6108        u16 sid;
6109        u8 ordered = 0;
6110
6111        data_hdr = chunk->subh.data_hdr = (sctp_datahdr_t *)chunk->skb->data;
6112        skb_pull(chunk->skb, sizeof(sctp_datahdr_t));
6113
6114        tsn = ntohl(data_hdr->tsn);
6115        pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6116
6117        /* ASSERT:  Now skb->data is really the user data.  */
6118
6119        /* Process ECN based congestion.
6120         *
6121         * Since the chunk structure is reused for all chunks within
6122         * a packet, we use ecn_ce_done to track if we've already
6123         * done CE processing for this packet.
6124         *
6125         * We need to do ECN processing even if we plan to discard the
6126         * chunk later.
6127         */
6128
6129        if (!chunk->ecn_ce_done) {
6130                struct sctp_af *af;
6131                chunk->ecn_ce_done = 1;
6132
6133                af = sctp_get_af_specific(
6134                        ipver2af(ip_hdr(chunk->skb)->version));
6135
6136                if (af && af->is_ce(chunk->skb) && asoc->peer.ecn_capable) {
6137                        /* Do real work as sideffect. */
6138                        sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6139                                        SCTP_U32(tsn));
6140                }
6141        }
6142
6143        tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6144        if (tmp < 0) {
6145                /* The TSN is too high--silently discard the chunk and
6146                 * count on it getting retransmitted later.
6147                 */
6148                if (chunk->asoc)
6149                        chunk->asoc->stats.outofseqtsns++;
6150                return SCTP_IERROR_HIGH_TSN;
6151        } else if (tmp > 0) {
6152                /* This is a duplicate.  Record it.  */
6153                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6154                return SCTP_IERROR_DUP_TSN;
6155        }
6156
6157        /* This is a new TSN.  */
6158
6159        /* Discard if there is no room in the receive window.
6160         * Actually, allow a little bit of overflow (up to a MTU).
6161         */
6162        datalen = ntohs(chunk->chunk_hdr->length);
6163        datalen -= sizeof(sctp_data_chunk_t);
6164
6165        deliver = SCTP_CMD_CHUNK_ULP;
6166
6167        /* Think about partial delivery. */
6168        if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6169
6170                /* Even if we don't accept this chunk there is
6171                 * memory pressure.
6172                 */
6173                sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6174        }
6175
6176        /* Spill over rwnd a little bit.  Note: While allowed, this spill over
6177         * seems a bit troublesome in that frag_point varies based on
6178         * PMTU.  In cases, such as loopback, this might be a rather
6179         * large spill over.
6180         */
6181        if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6182            (datalen > asoc->rwnd + asoc->frag_point))) {
6183
6184                /* If this is the next TSN, consider reneging to make
6185                 * room.   Note: Playing nice with a confused sender.  A
6186                 * malicious sender can still eat up all our buffer
6187                 * space and in the future we may want to detect and
6188                 * do more drastic reneging.
6189                 */
6190                if (sctp_tsnmap_has_gap(map) &&
6191                    (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6192                        pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6193                        deliver = SCTP_CMD_RENEGE;
6194                } else {
6195                        pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6196                                 __func__, tsn, datalen, asoc->rwnd);
6197
6198                        return SCTP_IERROR_IGNORE_TSN;
6199                }
6200        }
6201
6202        /*
6203         * Also try to renege to limit our memory usage in the event that
6204         * we are under memory pressure
6205         * If we can't renege, don't worry about it, the sk_rmem_schedule
6206         * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6207         * memory usage too much
6208         */
6209        if (*sk->sk_prot_creator->memory_pressure) {
6210                if (sctp_tsnmap_has_gap(map) &&
6211                    (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6212                        pr_debug("%s: under pressure, reneging for tsn:%u\n",
6213                                 __func__, tsn);
6214                        deliver = SCTP_CMD_RENEGE;
6215                 }
6216        }
6217
6218        /*
6219         * Section 3.3.10.9 No User Data (9)
6220         *
6221         * Cause of error
6222         * ---------------
6223         * No User Data:  This error cause is returned to the originator of a
6224         * DATA chunk if a received DATA chunk has no user data.
6225         */
6226        if (unlikely(0 == datalen)) {
6227                err = sctp_make_abort_no_data(asoc, chunk, tsn);
6228                if (err) {
6229                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6230                                        SCTP_CHUNK(err));
6231                }
6232                /* We are going to ABORT, so we might as well stop
6233                 * processing the rest of the chunks in the packet.
6234                 */
6235                sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6236                sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6237                                SCTP_ERROR(ECONNABORTED));
6238                sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6239                                SCTP_PERR(SCTP_ERROR_NO_DATA));
6240                SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6241                SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6242                return SCTP_IERROR_NO_DATA;
6243        }
6244
6245        chunk->data_accepted = 1;
6246
6247        /* Note: Some chunks may get overcounted (if we drop) or overcounted
6248         * if we renege and the chunk arrives again.
6249         */
6250        if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6251                SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6252                if (chunk->asoc)
6253                        chunk->asoc->stats.iuodchunks++;
6254        } else {
6255                SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6256                if (chunk->asoc)
6257                        chunk->asoc->stats.iodchunks++;
6258                ordered = 1;
6259        }
6260
6261        /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6262         *
6263         * If an endpoint receive a DATA chunk with an invalid stream
6264         * identifier, it shall acknowledge the reception of the DATA chunk
6265         * following the normal procedure, immediately send an ERROR chunk
6266         * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6267         * and discard the DATA chunk.
6268         */
6269        sid = ntohs(data_hdr->stream);
6270        if (sid >= asoc->c.sinit_max_instreams) {
6271                /* Mark tsn as received even though we drop it */
6272                sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6273
6274                err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6275                                         &data_hdr->stream,
6276                                         sizeof(data_hdr->stream),
6277                                         sizeof(u16));
6278                if (err)
6279                        sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6280                                        SCTP_CHUNK(err));
6281                return SCTP_IERROR_BAD_STREAM;
6282        }
6283
6284        /* Check to see if the SSN is possible for this TSN.
6285         * The biggest gap we can record is 4K wide.  Since SSNs wrap
6286         * at an unsigned short, there is no way that an SSN can
6287         * wrap and for a valid TSN.  We can simply check if the current
6288         * SSN is smaller then the next expected one.  If it is, it wrapped
6289         * and is invalid.
6290         */
6291        ssn = ntohs(data_hdr->ssn);
6292        if (ordered && SSN_lt(ssn, sctp_ssn_peek(&asoc->ssnmap->in, sid))) {
6293                return SCTP_IERROR_PROTO_VIOLATION;
6294        }
6295
6296        /* Send the data up to the user.  Note:  Schedule  the
6297         * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6298         * chunk needs the updated rwnd.
6299         */
6300        sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6301
6302        return SCTP_IERROR_NO_ERROR;
6303}
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