source: src/linux/universal/linux-3.18/net/llc/llc_conn.c @ 31869

Last change on this file since 31869 was 31869, checked in by brainslayer, 6 weeks ago

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1/*
2 * llc_conn.c - Driver routines for connection component.
3 *
4 * Copyright (c) 1997 by Procom Technology, Inc.
5 *               2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 *
7 * This program can be redistributed or modified under the terms of the
8 * GNU General Public License as published by the Free Software Foundation.
9 * This program is distributed without any warranty or implied warranty
10 * of merchantability or fitness for a particular purpose.
11 *
12 * See the GNU General Public License for more details.
13 */
14
15#include <linux/init.h>
16#include <linux/slab.h>
17#include <net/llc_sap.h>
18#include <net/llc_conn.h>
19#include <net/sock.h>
20#include <net/tcp_states.h>
21#include <net/llc_c_ev.h>
22#include <net/llc_c_ac.h>
23#include <net/llc_c_st.h>
24#include <net/llc_pdu.h>
25
26#if 0
27#define dprintk(args...) printk(KERN_DEBUG args)
28#else
29#define dprintk(args...)
30#endif
31
32static int llc_find_offset(int state, int ev_type);
33static void llc_conn_send_pdus(struct sock *sk);
34static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
35static int llc_exec_conn_trans_actions(struct sock *sk,
36                                       struct llc_conn_state_trans *trans,
37                                       struct sk_buff *ev);
38static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
39                                                        struct sk_buff *skb);
40
41/* Offset table on connection states transition diagram */
42static int llc_offset_table[NBR_CONN_STATES][NBR_CONN_EV];
43
44int sysctl_llc2_ack_timeout = LLC2_ACK_TIME * HZ;
45int sysctl_llc2_p_timeout = LLC2_P_TIME * HZ;
46int sysctl_llc2_rej_timeout = LLC2_REJ_TIME * HZ;
47int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ;
48
49/**
50 *      llc_conn_state_process - sends event to connection state machine
51 *      @sk: connection
52 *      @skb: occurred event
53 *
54 *      Sends an event to connection state machine. After processing event
55 *      (executing it's actions and changing state), upper layer will be
56 *      indicated or confirmed, if needed. Returns 0 for success, 1 for
57 *      failure. The socket lock has to be held before calling this function.
58 */
59int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
60{
61        int rc;
62        struct llc_sock *llc = llc_sk(skb->sk);
63        struct llc_conn_state_ev *ev = llc_conn_ev(skb);
64
65        /*
66         * We have to hold the skb, because llc_conn_service will kfree it in
67         * the sending path and we need to look at the skb->cb, where we encode
68         * llc_conn_state_ev.
69         */
70        skb_get(skb);
71        ev->ind_prim = ev->cfm_prim = 0;
72        /*
73         * Send event to state machine
74         */
75        rc = llc_conn_service(skb->sk, skb);
76        if (unlikely(rc != 0)) {
77                printk(KERN_ERR "%s: llc_conn_service failed\n", __func__);
78                goto out_kfree_skb;
79        }
80
81        if (unlikely(!ev->ind_prim && !ev->cfm_prim)) {
82                /* indicate or confirm not required */
83                if (!skb->next)
84                        goto out_kfree_skb;
85                goto out_skb_put;
86        }
87
88        if (unlikely(ev->ind_prim && ev->cfm_prim)) /* Paranoia */
89                skb_get(skb);
90
91        switch (ev->ind_prim) {
92        case LLC_DATA_PRIM:
93                llc_save_primitive(sk, skb, LLC_DATA_PRIM);
94                if (unlikely(sock_queue_rcv_skb(sk, skb))) {
95                        /*
96                         * shouldn't happen
97                         */
98                        printk(KERN_ERR "%s: sock_queue_rcv_skb failed!\n",
99                               __func__);
100                        kfree_skb(skb);
101                }
102                break;
103        case LLC_CONN_PRIM:
104                /*
105                 * Can't be sock_queue_rcv_skb, because we have to leave the
106                 * skb->sk pointing to the newly created struct sock in
107                 * llc_conn_handler. -acme
108                 */
109                skb_queue_tail(&sk->sk_receive_queue, skb);
110                sk->sk_state_change(sk);
111                break;
112        case LLC_DISC_PRIM:
113                sock_hold(sk);
114                if (sk->sk_type == SOCK_STREAM &&
115                    sk->sk_state == TCP_ESTABLISHED) {
116                        sk->sk_shutdown       = SHUTDOWN_MASK;
117                        sk->sk_socket->state  = SS_UNCONNECTED;
118                        sk->sk_state          = TCP_CLOSE;
119                        if (!sock_flag(sk, SOCK_DEAD)) {
120                                sock_set_flag(sk, SOCK_DEAD);
121                                sk->sk_state_change(sk);
122                        }
123                }
124                kfree_skb(skb);
125                sock_put(sk);
126                break;
127        case LLC_RESET_PRIM:
128                /*
129                 * FIXME:
130                 * RESET is not being notified to upper layers for now
131                 */
132                printk(KERN_INFO "%s: received a reset ind!\n", __func__);
133                kfree_skb(skb);
134                break;
135        default:
136                if (ev->ind_prim) {
137                        printk(KERN_INFO "%s: received unknown %d prim!\n",
138                                __func__, ev->ind_prim);
139                        kfree_skb(skb);
140                }
141                /* No indication */
142                break;
143        }
144
145        switch (ev->cfm_prim) {
146        case LLC_DATA_PRIM:
147                if (!llc_data_accept_state(llc->state))
148                        sk->sk_write_space(sk);
149                else
150                        rc = llc->failed_data_req = 1;
151                break;
152        case LLC_CONN_PRIM:
153                if (sk->sk_type == SOCK_STREAM &&
154                    sk->sk_state == TCP_SYN_SENT) {
155                        if (ev->status) {
156                                sk->sk_socket->state = SS_UNCONNECTED;
157                                sk->sk_state         = TCP_CLOSE;
158                        } else {
159                                sk->sk_socket->state = SS_CONNECTED;
160                                sk->sk_state         = TCP_ESTABLISHED;
161                        }
162                        sk->sk_state_change(sk);
163                }
164                break;
165        case LLC_DISC_PRIM:
166                sock_hold(sk);
167                if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSING) {
168                        sk->sk_socket->state = SS_UNCONNECTED;
169                        sk->sk_state         = TCP_CLOSE;
170                        sk->sk_state_change(sk);
171                }
172                sock_put(sk);
173                break;
174        case LLC_RESET_PRIM:
175                /*
176                 * FIXME:
177                 * RESET is not being notified to upper layers for now
178                 */
179                printk(KERN_INFO "%s: received a reset conf!\n", __func__);
180                break;
181        default:
182                if (ev->cfm_prim) {
183                        printk(KERN_INFO "%s: received unknown %d prim!\n",
184                                        __func__, ev->cfm_prim);
185                        break;
186                }
187                goto out_skb_put; /* No confirmation */
188        }
189out_kfree_skb:
190        kfree_skb(skb);
191out_skb_put:
192        kfree_skb(skb);
193        return rc;
194}
195
196void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
197{
198        /* queue PDU to send to MAC layer */
199        skb_queue_tail(&sk->sk_write_queue, skb);
200        llc_conn_send_pdus(sk);
201}
202
203/**
204 *      llc_conn_rtn_pdu - sends received data pdu to upper layer
205 *      @sk: Active connection
206 *      @skb: Received data frame
207 *
208 *      Sends received data pdu to upper layer (by using indicate function).
209 *      Prepares service parameters (prim and prim_data). calling indication
210 *      function will be done in llc_conn_state_process.
211 */
212void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb)
213{
214        struct llc_conn_state_ev *ev = llc_conn_ev(skb);
215
216        ev->ind_prim = LLC_DATA_PRIM;
217}
218
219/**
220 *      llc_conn_resend_i_pdu_as_cmd - resend all all unacknowledged I PDUs
221 *      @sk: active connection
222 *      @nr: NR
223 *      @first_p_bit: p_bit value of first pdu
224 *
225 *      Resend all unacknowledged I PDUs, starting with the NR; send first as
226 *      command PDU with P bit equal first_p_bit; if more than one send
227 *      subsequent as command PDUs with P bit equal zero (0).
228 */
229void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit)
230{
231        struct sk_buff *skb;
232        struct llc_pdu_sn *pdu;
233        u16 nbr_unack_pdus;
234        struct llc_sock *llc;
235        u8 howmany_resend = 0;
236
237        llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
238        if (!nbr_unack_pdus)
239                goto out;
240        /*
241         * Process unack PDUs only if unack queue is not empty; remove
242         * appropriate PDUs, fix them up, and put them on mac_pdu_q.
243         */
244        llc = llc_sk(sk);
245
246        while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
247                pdu = llc_pdu_sn_hdr(skb);
248                llc_pdu_set_cmd_rsp(skb, LLC_PDU_CMD);
249                llc_pdu_set_pf_bit(skb, first_p_bit);
250                skb_queue_tail(&sk->sk_write_queue, skb);
251                first_p_bit = 0;
252                llc->vS = LLC_I_GET_NS(pdu);
253                howmany_resend++;
254        }
255        if (howmany_resend > 0)
256                llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
257        /* any PDUs to re-send are queued up; start sending to MAC */
258        llc_conn_send_pdus(sk);
259out:;
260}
261
262/**
263 *      llc_conn_resend_i_pdu_as_rsp - Resend all unacknowledged I PDUs
264 *      @sk: active connection.
265 *      @nr: NR
266 *      @first_f_bit: f_bit value of first pdu.
267 *
268 *      Resend all unacknowledged I PDUs, starting with the NR; send first as
269 *      response PDU with F bit equal first_f_bit; if more than one send
270 *      subsequent as response PDUs with F bit equal zero (0).
271 */
272void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit)
273{
274        struct sk_buff *skb;
275        u16 nbr_unack_pdus;
276        struct llc_sock *llc = llc_sk(sk);
277        u8 howmany_resend = 0;
278
279        llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
280        if (!nbr_unack_pdus)
281                goto out;
282        /*
283         * Process unack PDUs only if unack queue is not empty; remove
284         * appropriate PDUs, fix them up, and put them on mac_pdu_q
285         */
286        while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
287                struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
288
289                llc_pdu_set_cmd_rsp(skb, LLC_PDU_RSP);
290                llc_pdu_set_pf_bit(skb, first_f_bit);
291                skb_queue_tail(&sk->sk_write_queue, skb);
292                first_f_bit = 0;
293                llc->vS = LLC_I_GET_NS(pdu);
294                howmany_resend++;
295        }
296        if (howmany_resend > 0)
297                llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
298        /* any PDUs to re-send are queued up; start sending to MAC */
299        llc_conn_send_pdus(sk);
300out:;
301}
302
303/**
304 *      llc_conn_remove_acked_pdus - Removes acknowledged pdus from tx queue
305 *      @sk: active connection
306 *      nr: NR
307 *      how_many_unacked: size of pdu_unack_q after removing acked pdus
308 *
309 *      Removes acknowledged pdus from transmit queue (pdu_unack_q). Returns
310 *      the number of pdus that removed from queue.
311 */
312int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked)
313{
314        int pdu_pos, i;
315        struct sk_buff *skb;
316        struct llc_pdu_sn *pdu;
317        int nbr_acked = 0;
318        struct llc_sock *llc = llc_sk(sk);
319        int q_len = skb_queue_len(&llc->pdu_unack_q);
320
321        if (!q_len)
322                goto out;
323        skb = skb_peek(&llc->pdu_unack_q);
324        pdu = llc_pdu_sn_hdr(skb);
325
326        /* finding position of last acked pdu in queue */
327        pdu_pos = ((int)LLC_2_SEQ_NBR_MODULO + (int)nr -
328                        (int)LLC_I_GET_NS(pdu)) % LLC_2_SEQ_NBR_MODULO;
329
330        for (i = 0; i < pdu_pos && i < q_len; i++) {
331                skb = skb_dequeue(&llc->pdu_unack_q);
332                kfree_skb(skb);
333                nbr_acked++;
334        }
335out:
336        *how_many_unacked = skb_queue_len(&llc->pdu_unack_q);
337        return nbr_acked;
338}
339
340/**
341 *      llc_conn_send_pdus - Sends queued PDUs
342 *      @sk: active connection
343 *
344 *      Sends queued pdus to MAC layer for transmission.
345 */
346static void llc_conn_send_pdus(struct sock *sk)
347{
348        struct sk_buff *skb;
349
350        while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
351                struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
352
353                if (LLC_PDU_TYPE_IS_I(pdu) &&
354                    !(skb->dev->flags & IFF_LOOPBACK)) {
355                        struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
356
357                        skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
358                        if (!skb2)
359                                break;
360                        skb = skb2;
361                }
362                dev_queue_xmit(skb);
363        }
364}
365
366/**
367 *      llc_conn_service - finds transition and changes state of connection
368 *      @sk: connection
369 *      @skb: happened event
370 *
371 *      This function finds transition that matches with happened event, then
372 *      executes related actions and finally changes state of connection.
373 *      Returns 0 for success, 1 for failure.
374 */
375static int llc_conn_service(struct sock *sk, struct sk_buff *skb)
376{
377        int rc = 1;
378        struct llc_sock *llc = llc_sk(sk);
379        struct llc_conn_state_trans *trans;
380
381        if (llc->state > NBR_CONN_STATES)
382                goto out;
383        rc = 0;
384        trans = llc_qualify_conn_ev(sk, skb);
385        if (trans) {
386                rc = llc_exec_conn_trans_actions(sk, trans, skb);
387                if (!rc && trans->next_state != NO_STATE_CHANGE) {
388                        llc->state = trans->next_state;
389                        if (!llc_data_accept_state(llc->state))
390                                sk->sk_state_change(sk);
391                }
392        }
393out:
394        return rc;
395}
396
397/**
398 *      llc_qualify_conn_ev - finds transition for event
399 *      @sk: connection
400 *      @skb: happened event
401 *
402 *      This function finds transition that matches with happened event.
403 *      Returns pointer to found transition on success, %NULL otherwise.
404 */
405static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
406                                                        struct sk_buff *skb)
407{
408        struct llc_conn_state_trans **next_trans;
409        llc_conn_ev_qfyr_t *next_qualifier;
410        struct llc_conn_state_ev *ev = llc_conn_ev(skb);
411        struct llc_sock *llc = llc_sk(sk);
412        struct llc_conn_state *curr_state =
413                                        &llc_conn_state_table[llc->state - 1];
414
415        /* search thru events for this state until
416         * list exhausted or until no more
417         */
418        for (next_trans = curr_state->transitions +
419                llc_find_offset(llc->state - 1, ev->type);
420             (*next_trans)->ev; next_trans++) {
421                if (!((*next_trans)->ev)(sk, skb)) {
422                        /* got POSSIBLE event match; the event may require
423                         * qualification based on the values of a number of
424                         * state flags; if all qualifications are met (i.e.,
425                         * if all qualifying functions return success, or 0,
426                         * then this is THE event we're looking for
427                         */
428                        for (next_qualifier = (*next_trans)->ev_qualifiers;
429                             next_qualifier && *next_qualifier &&
430                             !(*next_qualifier)(sk, skb); next_qualifier++)
431                                /* nothing */;
432                        if (!next_qualifier || !*next_qualifier)
433                                /* all qualifiers executed successfully; this is
434                                 * our transition; return it so we can perform
435                                 * the associated actions & change the state
436                                 */
437                                return *next_trans;
438                }
439        }
440        return NULL;
441}
442
443/**
444 *      llc_exec_conn_trans_actions - executes related actions
445 *      @sk: connection
446 *      @trans: transition that it's actions must be performed
447 *      @skb: event
448 *
449 *      Executes actions that is related to happened event. Returns 0 for
450 *      success, 1 to indicate failure of at least one action.
451 */
452static int llc_exec_conn_trans_actions(struct sock *sk,
453                                       struct llc_conn_state_trans *trans,
454                                       struct sk_buff *skb)
455{
456        int rc = 0;
457        llc_conn_action_t *next_action;
458
459        for (next_action = trans->ev_actions;
460             next_action && *next_action; next_action++) {
461                int rc2 = (*next_action)(sk, skb);
462
463                if (rc2 == 2) {
464                        rc = rc2;
465                        break;
466                } else if (rc2)
467                        rc = 1;
468        }
469        return rc;
470}
471
472static inline bool llc_estab_match(const struct llc_sap *sap,
473                                   const struct llc_addr *daddr,
474                                   const struct llc_addr *laddr,
475                                   const struct sock *sk)
476{
477        struct llc_sock *llc = llc_sk(sk);
478
479        return llc->laddr.lsap == laddr->lsap &&
480                llc->daddr.lsap == daddr->lsap &&
481                ether_addr_equal(llc->laddr.mac, laddr->mac) &&
482                ether_addr_equal(llc->daddr.mac, daddr->mac);
483}
484
485/**
486 *      __llc_lookup_established - Finds connection for the remote/local sap/mac
487 *      @sap: SAP
488 *      @daddr: address of remote LLC (MAC + SAP)
489 *      @laddr: address of local LLC (MAC + SAP)
490 *
491 *      Search connection list of the SAP and finds connection using the remote
492 *      mac, remote sap, local mac, and local sap. Returns pointer for
493 *      connection found, %NULL otherwise.
494 *      Caller has to make sure local_bh is disabled.
495 */
496static struct sock *__llc_lookup_established(struct llc_sap *sap,
497                                             struct llc_addr *daddr,
498                                             struct llc_addr *laddr)
499{
500        struct sock *rc;
501        struct hlist_nulls_node *node;
502        int slot = llc_sk_laddr_hashfn(sap, laddr);
503        struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
504
505        rcu_read_lock();
506again:
507        sk_nulls_for_each_rcu(rc, node, laddr_hb) {
508                if (llc_estab_match(sap, daddr, laddr, rc)) {
509                        /* Extra checks required by SLAB_DESTROY_BY_RCU */
510                        if (unlikely(!atomic_inc_not_zero(&rc->sk_refcnt)))
511                                goto again;
512                        if (unlikely(llc_sk(rc)->sap != sap ||
513                                     !llc_estab_match(sap, daddr, laddr, rc))) {
514                                sock_put(rc);
515                                continue;
516                        }
517                        goto found;
518                }
519        }
520        rc = NULL;
521        /*
522         * if the nulls value we got at the end of this lookup is
523         * not the expected one, we must restart lookup.
524         * We probably met an item that was moved to another chain.
525         */
526        if (unlikely(get_nulls_value(node) != slot))
527                goto again;
528found:
529        rcu_read_unlock();
530        return rc;
531}
532
533struct sock *llc_lookup_established(struct llc_sap *sap,
534                                    struct llc_addr *daddr,
535                                    struct llc_addr *laddr)
536{
537        struct sock *sk;
538
539        local_bh_disable();
540        sk = __llc_lookup_established(sap, daddr, laddr);
541        local_bh_enable();
542        return sk;
543}
544
545static inline bool llc_listener_match(const struct llc_sap *sap,
546                                      const struct llc_addr *laddr,
547                                      const struct sock *sk)
548{
549        struct llc_sock *llc = llc_sk(sk);
550
551        return sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN &&
552                llc->laddr.lsap == laddr->lsap &&
553                ether_addr_equal(llc->laddr.mac, laddr->mac);
554}
555
556static struct sock *__llc_lookup_listener(struct llc_sap *sap,
557                                          struct llc_addr *laddr)
558{
559        struct sock *rc;
560        struct hlist_nulls_node *node;
561        int slot = llc_sk_laddr_hashfn(sap, laddr);
562        struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
563
564        rcu_read_lock();
565again:
566        sk_nulls_for_each_rcu(rc, node, laddr_hb) {
567                if (llc_listener_match(sap, laddr, rc)) {
568                        /* Extra checks required by SLAB_DESTROY_BY_RCU */
569                        if (unlikely(!atomic_inc_not_zero(&rc->sk_refcnt)))
570                                goto again;
571                        if (unlikely(llc_sk(rc)->sap != sap ||
572                                     !llc_listener_match(sap, laddr, rc))) {
573                                sock_put(rc);
574                                continue;
575                        }
576                        goto found;
577                }
578        }
579        rc = NULL;
580        /*
581         * if the nulls value we got at the end of this lookup is
582         * not the expected one, we must restart lookup.
583         * We probably met an item that was moved to another chain.
584         */
585        if (unlikely(get_nulls_value(node) != slot))
586                goto again;
587found:
588        rcu_read_unlock();
589        return rc;
590}
591
592/**
593 *      llc_lookup_listener - Finds listener for local MAC + SAP
594 *      @sap: SAP
595 *      @laddr: address of local LLC (MAC + SAP)
596 *
597 *      Search connection list of the SAP and finds connection listening on
598 *      local mac, and local sap. Returns pointer for parent socket found,
599 *      %NULL otherwise.
600 *      Caller has to make sure local_bh is disabled.
601 */
602static struct sock *llc_lookup_listener(struct llc_sap *sap,
603                                        struct llc_addr *laddr)
604{
605        static struct llc_addr null_addr;
606        struct sock *rc = __llc_lookup_listener(sap, laddr);
607
608        if (!rc)
609                rc = __llc_lookup_listener(sap, &null_addr);
610
611        return rc;
612}
613
614static struct sock *__llc_lookup(struct llc_sap *sap,
615                                 struct llc_addr *daddr,
616                                 struct llc_addr *laddr)
617{
618        struct sock *sk = __llc_lookup_established(sap, daddr, laddr);
619
620        return sk ? : llc_lookup_listener(sap, laddr);
621}
622
623/**
624 *      llc_data_accept_state - designates if in this state data can be sent.
625 *      @state: state of connection.
626 *
627 *      Returns 0 if data can be sent, 1 otherwise.
628 */
629u8 llc_data_accept_state(u8 state)
630{
631        return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY &&
632               state != LLC_CONN_STATE_REJ;
633}
634
635/**
636 *      llc_find_next_offset - finds offset for next category of transitions
637 *      @state: state table.
638 *      @offset: start offset.
639 *
640 *      Finds offset of next category of transitions in transition table.
641 *      Returns the start index of next category.
642 */
643static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset)
644{
645        u16 cnt = 0;
646        struct llc_conn_state_trans **next_trans;
647
648        for (next_trans = state->transitions + offset;
649             (*next_trans)->ev; next_trans++)
650                ++cnt;
651        return cnt;
652}
653
654/**
655 *      llc_build_offset_table - builds offset table of connection
656 *
657 *      Fills offset table of connection state transition table
658 *      (llc_offset_table).
659 */
660void __init llc_build_offset_table(void)
661{
662        struct llc_conn_state *curr_state;
663        int state, ev_type, next_offset;
664
665        for (state = 0; state < NBR_CONN_STATES; state++) {
666                curr_state = &llc_conn_state_table[state];
667                next_offset = 0;
668                for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) {
669                        llc_offset_table[state][ev_type] = next_offset;
670                        next_offset += llc_find_next_offset(curr_state,
671                                                            next_offset) + 1;
672                }
673        }
674}
675
676/**
677 *      llc_find_offset - finds start offset of category of transitions
678 *      @state: state of connection
679 *      @ev_type: type of happened event
680 *
681 *      Finds start offset of desired category of transitions. Returns the
682 *      desired start offset.
683 */
684static int llc_find_offset(int state, int ev_type)
685{
686        int rc = 0;
687        /* at this stage, llc_offset_table[..][2] is not important. it is for
688         * init_pf_cycle and I don't know what is it.
689         */
690        switch (ev_type) {
691        case LLC_CONN_EV_TYPE_PRIM:
692                rc = llc_offset_table[state][0]; break;
693        case LLC_CONN_EV_TYPE_PDU:
694                rc = llc_offset_table[state][4]; break;
695        case LLC_CONN_EV_TYPE_SIMPLE:
696                rc = llc_offset_table[state][1]; break;
697        case LLC_CONN_EV_TYPE_P_TMR:
698        case LLC_CONN_EV_TYPE_ACK_TMR:
699        case LLC_CONN_EV_TYPE_REJ_TMR:
700        case LLC_CONN_EV_TYPE_BUSY_TMR:
701                rc = llc_offset_table[state][3]; break;
702        }
703        return rc;
704}
705
706/**
707 *      llc_sap_add_socket - adds a socket to a SAP
708 *      @sap: SAP
709 *      @sk: socket
710 *
711 *      This function adds a socket to the hash tables of a SAP.
712 */
713void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
714{
715        struct llc_sock *llc = llc_sk(sk);
716        struct hlist_head *dev_hb = llc_sk_dev_hash(sap, llc->dev->ifindex);
717        struct hlist_nulls_head *laddr_hb = llc_sk_laddr_hash(sap, &llc->laddr);
718
719        llc_sap_hold(sap);
720        llc_sk(sk)->sap = sap;
721
722        spin_lock_bh(&sap->sk_lock);
723        sap->sk_count++;
724        sk_nulls_add_node_rcu(sk, laddr_hb);
725        hlist_add_head(&llc->dev_hash_node, dev_hb);
726        spin_unlock_bh(&sap->sk_lock);
727}
728
729/**
730 *      llc_sap_remove_socket - removes a socket from SAP
731 *      @sap: SAP
732 *      @sk: socket
733 *
734 *      This function removes a connection from the hash tables of a SAP if
735 *      the connection was in this list.
736 */
737void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
738{
739        struct llc_sock *llc = llc_sk(sk);
740
741        spin_lock_bh(&sap->sk_lock);
742        sk_nulls_del_node_init_rcu(sk);
743        hlist_del(&llc->dev_hash_node);
744        sap->sk_count--;
745        spin_unlock_bh(&sap->sk_lock);
746        llc_sap_put(sap);
747}
748
749/**
750 *      llc_conn_rcv - sends received pdus to the connection state machine
751 *      @sk: current connection structure.
752 *      @skb: received frame.
753 *
754 *      Sends received pdus to the connection state machine.
755 */
756static int llc_conn_rcv(struct sock *sk, struct sk_buff *skb)
757{
758        struct llc_conn_state_ev *ev = llc_conn_ev(skb);
759
760        ev->type   = LLC_CONN_EV_TYPE_PDU;
761        ev->reason = 0;
762        return llc_conn_state_process(sk, skb);
763}
764
765static struct sock *llc_create_incoming_sock(struct sock *sk,
766                                             struct net_device *dev,
767                                             struct llc_addr *saddr,
768                                             struct llc_addr *daddr)
769{
770        struct sock *newsk = llc_sk_alloc(sock_net(sk), sk->sk_family, GFP_ATOMIC,
771                                          sk->sk_prot);
772        struct llc_sock *newllc, *llc = llc_sk(sk);
773
774        if (!newsk)
775                goto out;
776        newllc = llc_sk(newsk);
777        memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
778        memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
779        newllc->dev = dev;
780        dev_hold(dev);
781        llc_sap_add_socket(llc->sap, newsk);
782        llc_sap_hold(llc->sap);
783out:
784        return newsk;
785}
786
787void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
788{
789        struct llc_addr saddr, daddr;
790        struct sock *sk;
791
792        llc_pdu_decode_sa(skb, saddr.mac);
793        llc_pdu_decode_ssap(skb, &saddr.lsap);
794        llc_pdu_decode_da(skb, daddr.mac);
795        llc_pdu_decode_dsap(skb, &daddr.lsap);
796
797        sk = __llc_lookup(sap, &saddr, &daddr);
798        if (!sk)
799                goto drop;
800
801        bh_lock_sock(sk);
802        /*
803         * This has to be done here and not at the upper layer ->accept
804         * method because of the way the PROCOM state machine works:
805         * it needs to set several state variables (see, for instance,
806         * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
807         * the originator of the new connection, and this state has to be
808         * in the newly created struct sock private area. -acme
809         */
810        if (unlikely(sk->sk_state == TCP_LISTEN)) {
811                struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
812                                                              &saddr, &daddr);
813                if (!newsk)
814                        goto drop_unlock;
815                skb_set_owner_r(skb, newsk);
816        } else {
817                /*
818                 * Can't be skb_set_owner_r, this will be done at the
819                 * llc_conn_state_process function, later on, when we will use
820                 * skb_queue_rcv_skb to send it to upper layers, this is
821                 * another trick required to cope with how the PROCOM state
822                 * machine works. -acme
823                 */
824                skb_orphan(skb);
825                sock_hold(sk);
826                skb->sk = sk;
827                skb->destructor = sock_efree;
828        }
829        if (!sock_owned_by_user(sk))
830                llc_conn_rcv(sk, skb);
831        else {
832                dprintk("%s: adding to backlog...\n", __func__);
833                llc_set_backlog_type(skb, LLC_PACKET);
834                if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
835                        goto drop_unlock;
836        }
837out:
838        bh_unlock_sock(sk);
839        sock_put(sk);
840        return;
841drop:
842        kfree_skb(skb);
843        return;
844drop_unlock:
845        kfree_skb(skb);
846        goto out;
847}
848
849#undef LLC_REFCNT_DEBUG
850#ifdef LLC_REFCNT_DEBUG
851static atomic_t llc_sock_nr;
852#endif
853
854/**
855 *      llc_backlog_rcv - Processes rx frames and expired timers.
856 *      @sk: LLC sock (p8022 connection)
857 *      @skb: queued rx frame or event
858 *
859 *      This function processes frames that has received and timers that has
860 *      expired during sending an I pdu (refer to data_req_handler).  frames
861 *      queue by llc_rcv function (llc_mac.c) and timers queue by timer
862 *      callback functions(llc_c_ac.c).
863 */
864static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
865{
866        int rc = 0;
867        struct llc_sock *llc = llc_sk(sk);
868
869        if (likely(llc_backlog_type(skb) == LLC_PACKET)) {
870                if (likely(llc->state > 1)) /* not closed */
871                        rc = llc_conn_rcv(sk, skb);
872                else
873                        goto out_kfree_skb;
874        } else if (llc_backlog_type(skb) == LLC_EVENT) {
875                /* timer expiration event */
876                if (likely(llc->state > 1))  /* not closed */
877                        rc = llc_conn_state_process(sk, skb);
878                else
879                        goto out_kfree_skb;
880        } else {
881                printk(KERN_ERR "%s: invalid skb in backlog\n", __func__);
882                goto out_kfree_skb;
883        }
884out:
885        return rc;
886out_kfree_skb:
887        kfree_skb(skb);
888        goto out;
889}
890
891/**
892 *     llc_sk_init - Initializes a socket with default llc values.
893 *     @sk: socket to initialize.
894 *
895 *     Initializes a socket with default llc values.
896 */
897static void llc_sk_init(struct sock *sk)
898{
899        struct llc_sock *llc = llc_sk(sk);
900
901        llc->state    = LLC_CONN_STATE_ADM;
902        llc->inc_cntr = llc->dec_cntr = 2;
903        llc->dec_step = llc->connect_step = 1;
904
905        setup_timer(&llc->ack_timer.timer, llc_conn_ack_tmr_cb,
906                        (unsigned long)sk);
907        llc->ack_timer.expire         = sysctl_llc2_ack_timeout;
908
909        setup_timer(&llc->pf_cycle_timer.timer, llc_conn_pf_cycle_tmr_cb,
910                        (unsigned long)sk);
911        llc->pf_cycle_timer.expire         = sysctl_llc2_p_timeout;
912
913        setup_timer(&llc->rej_sent_timer.timer, llc_conn_rej_tmr_cb,
914                        (unsigned long)sk);
915        llc->rej_sent_timer.expire         = sysctl_llc2_rej_timeout;
916
917        setup_timer(&llc->busy_state_timer.timer, llc_conn_busy_tmr_cb,
918                        (unsigned long)sk);
919        llc->busy_state_timer.expire         = sysctl_llc2_busy_timeout;
920
921        llc->n2 = 2;   /* max retransmit */
922        llc->k  = 2;   /* tx win size, will adjust dynam */
923        llc->rw = 128; /* rx win size (opt and equal to
924                        * tx_win of remote LLC) */
925        skb_queue_head_init(&llc->pdu_unack_q);
926        sk->sk_backlog_rcv = llc_backlog_rcv;
927}
928
929/**
930 *      llc_sk_alloc - Allocates LLC sock
931 *      @family: upper layer protocol family
932 *      @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
933 *
934 *      Allocates a LLC sock and initializes it. Returns the new LLC sock
935 *      or %NULL if there's no memory available for one
936 */
937struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot)
938{
939        struct sock *sk = sk_alloc(net, family, priority, prot);
940
941        if (!sk)
942                goto out;
943        llc_sk_init(sk);
944        sock_init_data(NULL, sk);
945#ifdef LLC_REFCNT_DEBUG
946        atomic_inc(&llc_sock_nr);
947        printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk,
948                __func__, atomic_read(&llc_sock_nr));
949#endif
950out:
951        return sk;
952}
953
954/**
955 *      llc_sk_free - Frees a LLC socket
956 *      @sk - socket to free
957 *
958 *      Frees a LLC socket
959 */
960void llc_sk_free(struct sock *sk)
961{
962        struct llc_sock *llc = llc_sk(sk);
963
964        llc->state = LLC_CONN_OUT_OF_SVC;
965        /* Stop all (possibly) running timers */
966        llc_conn_ac_stop_all_timers(sk, NULL);
967#ifdef DEBUG_LLC_CONN_ALLOC
968        printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __func__,
969                skb_queue_len(&llc->pdu_unack_q),
970                skb_queue_len(&sk->sk_write_queue));
971#endif
972        skb_queue_purge(&sk->sk_receive_queue);
973        skb_queue_purge(&sk->sk_write_queue);
974        skb_queue_purge(&llc->pdu_unack_q);
975#ifdef LLC_REFCNT_DEBUG
976        if (atomic_read(&sk->sk_refcnt) != 1) {
977                printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
978                        sk, __func__, atomic_read(&sk->sk_refcnt));
979                printk(KERN_DEBUG "%d LLC sockets are still alive\n",
980                        atomic_read(&llc_sock_nr));
981        } else {
982                atomic_dec(&llc_sock_nr);
983                printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk,
984                        __func__, atomic_read(&llc_sock_nr));
985        }
986#endif
987        sock_put(sk);
988}
989
990/**
991 *      llc_sk_reset - resets a connection
992 *      @sk: LLC socket to reset
993 *
994 *      Resets a connection to the out of service state. Stops its timers
995 *      and frees any frames in the queues of the connection.
996 */
997void llc_sk_reset(struct sock *sk)
998{
999        struct llc_sock *llc = llc_sk(sk);
1000
1001        llc_conn_ac_stop_all_timers(sk, NULL);
1002        skb_queue_purge(&sk->sk_write_queue);
1003        skb_queue_purge(&llc->pdu_unack_q);
1004        llc->remote_busy_flag   = 0;
1005        llc->cause_flag         = 0;
1006        llc->retry_count        = 0;
1007        llc_conn_set_p_flag(sk, 0);
1008        llc->f_flag             = 0;
1009        llc->s_flag             = 0;
1010        llc->ack_pf             = 0;
1011        llc->first_pdu_Ns       = 0;
1012        llc->ack_must_be_send   = 0;
1013        llc->dec_step           = 1;
1014        llc->inc_cntr           = 2;
1015        llc->dec_cntr           = 2;
1016        llc->X                  = 0;
1017        llc->failed_data_req    = 0 ;
1018        llc->last_nr            = 0;
1019}
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