Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/jaswinder...
[linux-2.6.git] / net / llc / llc_conn.c
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 <net/llc_sap.h>
17 #include <net/llc_conn.h>
18 #include <net/sock.h>
19 #include <net/tcp_states.h>
20 #include <net/llc_c_ev.h>
21 #include <net/llc_c_ac.h>
22 #include <net/llc_c_st.h>
23 #include <net/llc_pdu.h>
24
25 #if 0
26 #define dprintk(args...) printk(KERN_DEBUG args)
27 #else
28 #define dprintk(args...)
29 #endif
30
31 static int llc_find_offset(int state, int ev_type);
32 static void llc_conn_send_pdus(struct sock *sk);
33 static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
34 static int llc_exec_conn_trans_actions(struct sock *sk,
35                                        struct llc_conn_state_trans *trans,
36                                        struct sk_buff *ev);
37 static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
38                                                         struct sk_buff *skb);
39
40 /* Offset table on connection states transition diagram */
41 static int llc_offset_table[NBR_CONN_STATES][NBR_CONN_EV];
42
43 int sysctl_llc2_ack_timeout = LLC2_ACK_TIME * HZ;
44 int sysctl_llc2_p_timeout = LLC2_P_TIME * HZ;
45 int sysctl_llc2_rej_timeout = LLC2_REJ_TIME * HZ;
46 int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ;
47
48 /**
49  *      llc_conn_state_process - sends event to connection state machine
50  *      @sk: connection
51  *      @skb: occurred event
52  *
53  *      Sends an event to connection state machine. After processing event
54  *      (executing it's actions and changing state), upper layer will be
55  *      indicated or confirmed, if needed. Returns 0 for success, 1 for
56  *      failure. The socket lock has to be held before calling this function.
57  */
58 int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
59 {
60         int rc;
61         struct llc_sock *llc = llc_sk(skb->sk);
62         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
63
64         /*
65          * We have to hold the skb, because llc_conn_service will kfree it in
66          * the sending path and we need to look at the skb->cb, where we encode
67          * llc_conn_state_ev.
68          */
69         skb_get(skb);
70         ev->ind_prim = ev->cfm_prim = 0;
71         /*
72          * Send event to state machine
73          */
74         rc = llc_conn_service(skb->sk, skb);
75         if (unlikely(rc != 0)) {
76                 printk(KERN_ERR "%s: llc_conn_service failed\n", __func__);
77                 goto out_kfree_skb;
78         }
79
80         if (unlikely(!ev->ind_prim && !ev->cfm_prim)) {
81                 /* indicate or confirm not required */
82                 /* XXX this is not very pretty, perhaps we should store
83                  * XXX indicate/confirm-needed state in the llc_conn_state_ev
84                  * XXX control block of the SKB instead? -DaveM
85                  */
86                 if (!skb->next)
87                         goto out_kfree_skb;
88                 goto out_skb_put;
89         }
90
91         if (unlikely(ev->ind_prim && ev->cfm_prim)) /* Paranoia */
92                 skb_get(skb);
93
94         switch (ev->ind_prim) {
95         case LLC_DATA_PRIM:
96                 llc_save_primitive(sk, skb, LLC_DATA_PRIM);
97                 if (unlikely(sock_queue_rcv_skb(sk, skb))) {
98                         /*
99                          * shouldn't happen
100                          */
101                         printk(KERN_ERR "%s: sock_queue_rcv_skb failed!\n",
102                                __func__);
103                         kfree_skb(skb);
104                 }
105                 break;
106         case LLC_CONN_PRIM:
107                 /*
108                  * Can't be sock_queue_rcv_skb, because we have to leave the
109                  * skb->sk pointing to the newly created struct sock in
110                  * llc_conn_handler. -acme
111                  */
112                 skb_queue_tail(&sk->sk_receive_queue, skb);
113                 sk->sk_state_change(sk);
114                 break;
115         case LLC_DISC_PRIM:
116                 sock_hold(sk);
117                 if (sk->sk_type == SOCK_STREAM &&
118                     sk->sk_state == TCP_ESTABLISHED) {
119                         sk->sk_shutdown       = SHUTDOWN_MASK;
120                         sk->sk_socket->state  = SS_UNCONNECTED;
121                         sk->sk_state          = TCP_CLOSE;
122                         if (!sock_flag(sk, SOCK_DEAD)) {
123                                 sock_set_flag(sk, SOCK_DEAD);
124                                 sk->sk_state_change(sk);
125                         }
126                 }
127                 kfree_skb(skb);
128                 sock_put(sk);
129                 break;
130         case LLC_RESET_PRIM:
131                 /*
132                  * FIXME:
133                  * RESET is not being notified to upper layers for now
134                  */
135                 printk(KERN_INFO "%s: received a reset ind!\n", __func__);
136                 kfree_skb(skb);
137                 break;
138         default:
139                 if (ev->ind_prim) {
140                         printk(KERN_INFO "%s: received unknown %d prim!\n",
141                                 __func__, ev->ind_prim);
142                         kfree_skb(skb);
143                 }
144                 /* No indication */
145                 break;
146         }
147
148         switch (ev->cfm_prim) {
149         case LLC_DATA_PRIM:
150                 if (!llc_data_accept_state(llc->state))
151                         sk->sk_write_space(sk);
152                 else
153                         rc = llc->failed_data_req = 1;
154                 break;
155         case LLC_CONN_PRIM:
156                 if (sk->sk_type == SOCK_STREAM &&
157                     sk->sk_state == TCP_SYN_SENT) {
158                         if (ev->status) {
159                                 sk->sk_socket->state = SS_UNCONNECTED;
160                                 sk->sk_state         = TCP_CLOSE;
161                         } else {
162                                 sk->sk_socket->state = SS_CONNECTED;
163                                 sk->sk_state         = TCP_ESTABLISHED;
164                         }
165                         sk->sk_state_change(sk);
166                 }
167                 break;
168         case LLC_DISC_PRIM:
169                 sock_hold(sk);
170                 if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSING) {
171                         sk->sk_socket->state = SS_UNCONNECTED;
172                         sk->sk_state         = TCP_CLOSE;
173                         sk->sk_state_change(sk);
174                 }
175                 sock_put(sk);
176                 break;
177         case LLC_RESET_PRIM:
178                 /*
179                  * FIXME:
180                  * RESET is not being notified to upper layers for now
181                  */
182                 printk(KERN_INFO "%s: received a reset conf!\n", __func__);
183                 break;
184         default:
185                 if (ev->cfm_prim) {
186                         printk(KERN_INFO "%s: received unknown %d prim!\n",
187                                         __func__, ev->cfm_prim);
188                         break;
189                 }
190                 goto out_skb_put; /* No confirmation */
191         }
192 out_kfree_skb:
193         kfree_skb(skb);
194 out_skb_put:
195         kfree_skb(skb);
196         return rc;
197 }
198
199 void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
200 {
201         /* queue PDU to send to MAC layer */
202         skb_queue_tail(&sk->sk_write_queue, skb);
203         llc_conn_send_pdus(sk);
204 }
205
206 /**
207  *      llc_conn_rtn_pdu - sends received data pdu to upper layer
208  *      @sk: Active connection
209  *      @skb: Received data frame
210  *
211  *      Sends received data pdu to upper layer (by using indicate function).
212  *      Prepares service parameters (prim and prim_data). calling indication
213  *      function will be done in llc_conn_state_process.
214  */
215 void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb)
216 {
217         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
218
219         ev->ind_prim = LLC_DATA_PRIM;
220 }
221
222 /**
223  *      llc_conn_resend_i_pdu_as_cmd - resend all all unacknowledged I PDUs
224  *      @sk: active connection
225  *      @nr: NR
226  *      @first_p_bit: p_bit value of first pdu
227  *
228  *      Resend all unacknowledged I PDUs, starting with the NR; send first as
229  *      command PDU with P bit equal first_p_bit; if more than one send
230  *      subsequent as command PDUs with P bit equal zero (0).
231  */
232 void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit)
233 {
234         struct sk_buff *skb;
235         struct llc_pdu_sn *pdu;
236         u16 nbr_unack_pdus;
237         struct llc_sock *llc;
238         u8 howmany_resend = 0;
239
240         llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
241         if (!nbr_unack_pdus)
242                 goto out;
243         /*
244          * Process unack PDUs only if unack queue is not empty; remove
245          * appropriate PDUs, fix them up, and put them on mac_pdu_q.
246          */
247         llc = llc_sk(sk);
248
249         while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
250                 pdu = llc_pdu_sn_hdr(skb);
251                 llc_pdu_set_cmd_rsp(skb, LLC_PDU_CMD);
252                 llc_pdu_set_pf_bit(skb, first_p_bit);
253                 skb_queue_tail(&sk->sk_write_queue, skb);
254                 first_p_bit = 0;
255                 llc->vS = LLC_I_GET_NS(pdu);
256                 howmany_resend++;
257         }
258         if (howmany_resend > 0)
259                 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
260         /* any PDUs to re-send are queued up; start sending to MAC */
261         llc_conn_send_pdus(sk);
262 out:;
263 }
264
265 /**
266  *      llc_conn_resend_i_pdu_as_rsp - Resend all unacknowledged I PDUs
267  *      @sk: active connection.
268  *      @nr: NR
269  *      @first_f_bit: f_bit value of first pdu.
270  *
271  *      Resend all unacknowledged I PDUs, starting with the NR; send first as
272  *      response PDU with F bit equal first_f_bit; if more than one send
273  *      subsequent as response PDUs with F bit equal zero (0).
274  */
275 void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit)
276 {
277         struct sk_buff *skb;
278         u16 nbr_unack_pdus;
279         struct llc_sock *llc = llc_sk(sk);
280         u8 howmany_resend = 0;
281
282         llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
283         if (!nbr_unack_pdus)
284                 goto out;
285         /*
286          * Process unack PDUs only if unack queue is not empty; remove
287          * appropriate PDUs, fix them up, and put them on mac_pdu_q
288          */
289         while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
290                 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
291
292                 llc_pdu_set_cmd_rsp(skb, LLC_PDU_RSP);
293                 llc_pdu_set_pf_bit(skb, first_f_bit);
294                 skb_queue_tail(&sk->sk_write_queue, skb);
295                 first_f_bit = 0;
296                 llc->vS = LLC_I_GET_NS(pdu);
297                 howmany_resend++;
298         }
299         if (howmany_resend > 0)
300                 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
301         /* any PDUs to re-send are queued up; start sending to MAC */
302         llc_conn_send_pdus(sk);
303 out:;
304 }
305
306 /**
307  *      llc_conn_remove_acked_pdus - Removes acknowledged pdus from tx queue
308  *      @sk: active connection
309  *      nr: NR
310  *      how_many_unacked: size of pdu_unack_q after removing acked pdus
311  *
312  *      Removes acknowledged pdus from transmit queue (pdu_unack_q). Returns
313  *      the number of pdus that removed from queue.
314  */
315 int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked)
316 {
317         int pdu_pos, i;
318         struct sk_buff *skb;
319         struct llc_pdu_sn *pdu;
320         int nbr_acked = 0;
321         struct llc_sock *llc = llc_sk(sk);
322         int q_len = skb_queue_len(&llc->pdu_unack_q);
323
324         if (!q_len)
325                 goto out;
326         skb = skb_peek(&llc->pdu_unack_q);
327         pdu = llc_pdu_sn_hdr(skb);
328
329         /* finding position of last acked pdu in queue */
330         pdu_pos = ((int)LLC_2_SEQ_NBR_MODULO + (int)nr -
331                         (int)LLC_I_GET_NS(pdu)) % LLC_2_SEQ_NBR_MODULO;
332
333         for (i = 0; i < pdu_pos && i < q_len; i++) {
334                 skb = skb_dequeue(&llc->pdu_unack_q);
335                 kfree_skb(skb);
336                 nbr_acked++;
337         }
338 out:
339         *how_many_unacked = skb_queue_len(&llc->pdu_unack_q);
340         return nbr_acked;
341 }
342
343 /**
344  *      llc_conn_send_pdus - Sends queued PDUs
345  *      @sk: active connection
346  *
347  *      Sends queued pdus to MAC layer for transmission.
348  */
349 static void llc_conn_send_pdus(struct sock *sk)
350 {
351         struct sk_buff *skb;
352
353         while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
354                 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
355
356                 if (LLC_PDU_TYPE_IS_I(pdu) &&
357                     !(skb->dev->flags & IFF_LOOPBACK)) {
358                         struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
359
360                         skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
361                         if (!skb2)
362                                 break;
363                         skb = skb2;
364                 }
365                 dev_queue_xmit(skb);
366         }
367 }
368
369 /**
370  *      llc_conn_service - finds transition and changes state of connection
371  *      @sk: connection
372  *      @skb: happened event
373  *
374  *      This function finds transition that matches with happened event, then
375  *      executes related actions and finally changes state of connection.
376  *      Returns 0 for success, 1 for failure.
377  */
378 static int llc_conn_service(struct sock *sk, struct sk_buff *skb)
379 {
380         int rc = 1;
381         struct llc_sock *llc = llc_sk(sk);
382         struct llc_conn_state_trans *trans;
383
384         if (llc->state > NBR_CONN_STATES)
385                 goto out;
386         rc = 0;
387         trans = llc_qualify_conn_ev(sk, skb);
388         if (trans) {
389                 rc = llc_exec_conn_trans_actions(sk, trans, skb);
390                 if (!rc && trans->next_state != NO_STATE_CHANGE) {
391                         llc->state = trans->next_state;
392                         if (!llc_data_accept_state(llc->state))
393                                 sk->sk_state_change(sk);
394                 }
395         }
396 out:
397         return rc;
398 }
399
400 /**
401  *      llc_qualify_conn_ev - finds transition for event
402  *      @sk: connection
403  *      @skb: happened event
404  *
405  *      This function finds transition that matches with happened event.
406  *      Returns pointer to found transition on success, %NULL otherwise.
407  */
408 static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
409                                                         struct sk_buff *skb)
410 {
411         struct llc_conn_state_trans **next_trans;
412         llc_conn_ev_qfyr_t *next_qualifier;
413         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
414         struct llc_sock *llc = llc_sk(sk);
415         struct llc_conn_state *curr_state =
416                                         &llc_conn_state_table[llc->state - 1];
417
418         /* search thru events for this state until
419          * list exhausted or until no more
420          */
421         for (next_trans = curr_state->transitions +
422                 llc_find_offset(llc->state - 1, ev->type);
423              (*next_trans)->ev; next_trans++) {
424                 if (!((*next_trans)->ev)(sk, skb)) {
425                         /* got POSSIBLE event match; the event may require
426                          * qualification based on the values of a number of
427                          * state flags; if all qualifications are met (i.e.,
428                          * if all qualifying functions return success, or 0,
429                          * then this is THE event we're looking for
430                          */
431                         for (next_qualifier = (*next_trans)->ev_qualifiers;
432                              next_qualifier && *next_qualifier &&
433                              !(*next_qualifier)(sk, skb); next_qualifier++)
434                                 /* nothing */;
435                         if (!next_qualifier || !*next_qualifier)
436                                 /* all qualifiers executed successfully; this is
437                                  * our transition; return it so we can perform
438                                  * the associated actions & change the state
439                                  */
440                                 return *next_trans;
441                 }
442         }
443         return NULL;
444 }
445
446 /**
447  *      llc_exec_conn_trans_actions - executes related actions
448  *      @sk: connection
449  *      @trans: transition that it's actions must be performed
450  *      @skb: event
451  *
452  *      Executes actions that is related to happened event. Returns 0 for
453  *      success, 1 to indicate failure of at least one action.
454  */
455 static int llc_exec_conn_trans_actions(struct sock *sk,
456                                        struct llc_conn_state_trans *trans,
457                                        struct sk_buff *skb)
458 {
459         int rc = 0;
460         llc_conn_action_t *next_action;
461
462         for (next_action = trans->ev_actions;
463              next_action && *next_action; next_action++) {
464                 int rc2 = (*next_action)(sk, skb);
465
466                 if (rc2 == 2) {
467                         rc = rc2;
468                         break;
469                 } else if (rc2)
470                         rc = 1;
471         }
472         return rc;
473 }
474
475 /**
476  *      __llc_lookup_established - Finds connection for the remote/local sap/mac
477  *      @sap: SAP
478  *      @daddr: address of remote LLC (MAC + SAP)
479  *      @laddr: address of local LLC (MAC + SAP)
480  *
481  *      Search connection list of the SAP and finds connection using the remote
482  *      mac, remote sap, local mac, and local sap. Returns pointer for
483  *      connection found, %NULL otherwise.
484  *      Caller has to make sure local_bh is disabled.
485  */
486 static struct sock *__llc_lookup_established(struct llc_sap *sap,
487                                              struct llc_addr *daddr,
488                                              struct llc_addr *laddr)
489 {
490         struct sock *rc;
491         struct hlist_node *node;
492
493         read_lock(&sap->sk_list.lock);
494         sk_for_each(rc, node, &sap->sk_list.list) {
495                 struct llc_sock *llc = llc_sk(rc);
496
497                 if (llc->laddr.lsap == laddr->lsap &&
498                     llc->daddr.lsap == daddr->lsap &&
499                     llc_mac_match(llc->laddr.mac, laddr->mac) &&
500                     llc_mac_match(llc->daddr.mac, daddr->mac)) {
501                         sock_hold(rc);
502                         goto found;
503                 }
504         }
505         rc = NULL;
506 found:
507         read_unlock(&sap->sk_list.lock);
508         return rc;
509 }
510
511 struct sock *llc_lookup_established(struct llc_sap *sap,
512                                     struct llc_addr *daddr,
513                                     struct llc_addr *laddr)
514 {
515         struct sock *sk;
516
517         local_bh_disable();
518         sk = __llc_lookup_established(sap, daddr, laddr);
519         local_bh_enable();
520         return sk;
521 }
522
523 /**
524  *      llc_lookup_listener - Finds listener for local MAC + SAP
525  *      @sap: SAP
526  *      @laddr: address of local LLC (MAC + SAP)
527  *
528  *      Search connection list of the SAP and finds connection listening on
529  *      local mac, and local sap. Returns pointer for parent socket found,
530  *      %NULL otherwise.
531  *      Caller has to make sure local_bh is disabled.
532  */
533 static struct sock *llc_lookup_listener(struct llc_sap *sap,
534                                         struct llc_addr *laddr)
535 {
536         struct sock *rc;
537         struct hlist_node *node;
538
539         read_lock(&sap->sk_list.lock);
540         sk_for_each(rc, node, &sap->sk_list.list) {
541                 struct llc_sock *llc = llc_sk(rc);
542
543                 if (rc->sk_type == SOCK_STREAM && rc->sk_state == TCP_LISTEN &&
544                     llc->laddr.lsap == laddr->lsap &&
545                     (llc_mac_match(llc->laddr.mac, laddr->mac) ||
546                      llc_mac_null(llc->laddr.mac))) {
547                         sock_hold(rc);
548                         goto found;
549                 }
550         }
551         rc = NULL;
552 found:
553         read_unlock(&sap->sk_list.lock);
554         return rc;
555 }
556
557 static struct sock *__llc_lookup(struct llc_sap *sap,
558                                  struct llc_addr *daddr,
559                                  struct llc_addr *laddr)
560 {
561         struct sock *sk = __llc_lookup_established(sap, daddr, laddr);
562
563         return sk ? : llc_lookup_listener(sap, laddr);
564 }
565
566 /**
567  *      llc_data_accept_state - designates if in this state data can be sent.
568  *      @state: state of connection.
569  *
570  *      Returns 0 if data can be sent, 1 otherwise.
571  */
572 u8 llc_data_accept_state(u8 state)
573 {
574         return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY &&
575                state != LLC_CONN_STATE_REJ;
576 }
577
578 /**
579  *      llc_find_next_offset - finds offset for next category of transitions
580  *      @state: state table.
581  *      @offset: start offset.
582  *
583  *      Finds offset of next category of transitions in transition table.
584  *      Returns the start index of next category.
585  */
586 static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset)
587 {
588         u16 cnt = 0;
589         struct llc_conn_state_trans **next_trans;
590
591         for (next_trans = state->transitions + offset;
592              (*next_trans)->ev; next_trans++)
593                 ++cnt;
594         return cnt;
595 }
596
597 /**
598  *      llc_build_offset_table - builds offset table of connection
599  *
600  *      Fills offset table of connection state transition table
601  *      (llc_offset_table).
602  */
603 void __init llc_build_offset_table(void)
604 {
605         struct llc_conn_state *curr_state;
606         int state, ev_type, next_offset;
607
608         for (state = 0; state < NBR_CONN_STATES; state++) {
609                 curr_state = &llc_conn_state_table[state];
610                 next_offset = 0;
611                 for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) {
612                         llc_offset_table[state][ev_type] = next_offset;
613                         next_offset += llc_find_next_offset(curr_state,
614                                                             next_offset) + 1;
615                 }
616         }
617 }
618
619 /**
620  *      llc_find_offset - finds start offset of category of transitions
621  *      @state: state of connection
622  *      @ev_type: type of happened event
623  *
624  *      Finds start offset of desired category of transitions. Returns the
625  *      desired start offset.
626  */
627 static int llc_find_offset(int state, int ev_type)
628 {
629         int rc = 0;
630         /* at this stage, llc_offset_table[..][2] is not important. it is for
631          * init_pf_cycle and I don't know what is it.
632          */
633         switch (ev_type) {
634         case LLC_CONN_EV_TYPE_PRIM:
635                 rc = llc_offset_table[state][0]; break;
636         case LLC_CONN_EV_TYPE_PDU:
637                 rc = llc_offset_table[state][4]; break;
638         case LLC_CONN_EV_TYPE_SIMPLE:
639                 rc = llc_offset_table[state][1]; break;
640         case LLC_CONN_EV_TYPE_P_TMR:
641         case LLC_CONN_EV_TYPE_ACK_TMR:
642         case LLC_CONN_EV_TYPE_REJ_TMR:
643         case LLC_CONN_EV_TYPE_BUSY_TMR:
644                 rc = llc_offset_table[state][3]; break;
645         }
646         return rc;
647 }
648
649 /**
650  *      llc_sap_add_socket - adds a socket to a SAP
651  *      @sap: SAP
652  *      @sk: socket
653  *
654  *      This function adds a socket to sk_list of a SAP.
655  */
656 void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
657 {
658         llc_sap_hold(sap);
659         write_lock_bh(&sap->sk_list.lock);
660         llc_sk(sk)->sap = sap;
661         sk_add_node(sk, &sap->sk_list.list);
662         write_unlock_bh(&sap->sk_list.lock);
663 }
664
665 /**
666  *      llc_sap_remove_socket - removes a socket from SAP
667  *      @sap: SAP
668  *      @sk: socket
669  *
670  *      This function removes a connection from sk_list.list of a SAP if
671  *      the connection was in this list.
672  */
673 void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
674 {
675         write_lock_bh(&sap->sk_list.lock);
676         sk_del_node_init(sk);
677         write_unlock_bh(&sap->sk_list.lock);
678         llc_sap_put(sap);
679 }
680
681 /**
682  *      llc_conn_rcv - sends received pdus to the connection state machine
683  *      @sk: current connection structure.
684  *      @skb: received frame.
685  *
686  *      Sends received pdus to the connection state machine.
687  */
688 static int llc_conn_rcv(struct sock* sk, struct sk_buff *skb)
689 {
690         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
691
692         ev->type   = LLC_CONN_EV_TYPE_PDU;
693         ev->reason = 0;
694         return llc_conn_state_process(sk, skb);
695 }
696
697 static struct sock *llc_create_incoming_sock(struct sock *sk,
698                                              struct net_device *dev,
699                                              struct llc_addr *saddr,
700                                              struct llc_addr *daddr)
701 {
702         struct sock *newsk = llc_sk_alloc(sock_net(sk), sk->sk_family, GFP_ATOMIC,
703                                           sk->sk_prot);
704         struct llc_sock *newllc, *llc = llc_sk(sk);
705
706         if (!newsk)
707                 goto out;
708         newllc = llc_sk(newsk);
709         memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
710         memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
711         newllc->dev = dev;
712         dev_hold(dev);
713         llc_sap_add_socket(llc->sap, newsk);
714         llc_sap_hold(llc->sap);
715 out:
716         return newsk;
717 }
718
719 void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
720 {
721         struct llc_addr saddr, daddr;
722         struct sock *sk;
723
724         llc_pdu_decode_sa(skb, saddr.mac);
725         llc_pdu_decode_ssap(skb, &saddr.lsap);
726         llc_pdu_decode_da(skb, daddr.mac);
727         llc_pdu_decode_dsap(skb, &daddr.lsap);
728
729         sk = __llc_lookup(sap, &saddr, &daddr);
730         if (!sk)
731                 goto drop;
732
733         bh_lock_sock(sk);
734         /*
735          * This has to be done here and not at the upper layer ->accept
736          * method because of the way the PROCOM state machine works:
737          * it needs to set several state variables (see, for instance,
738          * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
739          * the originator of the new connection, and this state has to be
740          * in the newly created struct sock private area. -acme
741          */
742         if (unlikely(sk->sk_state == TCP_LISTEN)) {
743                 struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
744                                                               &saddr, &daddr);
745                 if (!newsk)
746                         goto drop_unlock;
747                 skb_set_owner_r(skb, newsk);
748         } else {
749                 /*
750                  * Can't be skb_set_owner_r, this will be done at the
751                  * llc_conn_state_process function, later on, when we will use
752                  * skb_queue_rcv_skb to send it to upper layers, this is
753                  * another trick required to cope with how the PROCOM state
754                  * machine works. -acme
755                  */
756                 skb->sk = sk;
757         }
758         if (!sock_owned_by_user(sk))
759                 llc_conn_rcv(sk, skb);
760         else {
761                 dprintk("%s: adding to backlog...\n", __func__);
762                 llc_set_backlog_type(skb, LLC_PACKET);
763                 sk_add_backlog(sk, skb);
764         }
765 out:
766         bh_unlock_sock(sk);
767         sock_put(sk);
768         return;
769 drop:
770         kfree_skb(skb);
771         return;
772 drop_unlock:
773         kfree_skb(skb);
774         goto out;
775 }
776
777 #undef LLC_REFCNT_DEBUG
778 #ifdef LLC_REFCNT_DEBUG
779 static atomic_t llc_sock_nr;
780 #endif
781
782 /**
783  *      llc_backlog_rcv - Processes rx frames and expired timers.
784  *      @sk: LLC sock (p8022 connection)
785  *      @skb: queued rx frame or event
786  *
787  *      This function processes frames that has received and timers that has
788  *      expired during sending an I pdu (refer to data_req_handler).  frames
789  *      queue by llc_rcv function (llc_mac.c) and timers queue by timer
790  *      callback functions(llc_c_ac.c).
791  */
792 static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
793 {
794         int rc = 0;
795         struct llc_sock *llc = llc_sk(sk);
796
797         if (likely(llc_backlog_type(skb) == LLC_PACKET)) {
798                 if (likely(llc->state > 1)) /* not closed */
799                         rc = llc_conn_rcv(sk, skb);
800                 else
801                         goto out_kfree_skb;
802         } else if (llc_backlog_type(skb) == LLC_EVENT) {
803                 /* timer expiration event */
804                 if (likely(llc->state > 1))  /* not closed */
805                         rc = llc_conn_state_process(sk, skb);
806                 else
807                         goto out_kfree_skb;
808         } else {
809                 printk(KERN_ERR "%s: invalid skb in backlog\n", __func__);
810                 goto out_kfree_skb;
811         }
812 out:
813         return rc;
814 out_kfree_skb:
815         kfree_skb(skb);
816         goto out;
817 }
818
819 /**
820  *     llc_sk_init - Initializes a socket with default llc values.
821  *     @sk: socket to initialize.
822  *
823  *     Initializes a socket with default llc values.
824  */
825 static void llc_sk_init(struct sock* sk)
826 {
827         struct llc_sock *llc = llc_sk(sk);
828
829         llc->state    = LLC_CONN_STATE_ADM;
830         llc->inc_cntr = llc->dec_cntr = 2;
831         llc->dec_step = llc->connect_step = 1;
832
833         setup_timer(&llc->ack_timer.timer, llc_conn_ack_tmr_cb,
834                         (unsigned long)sk);
835         llc->ack_timer.expire         = sysctl_llc2_ack_timeout;
836
837         setup_timer(&llc->pf_cycle_timer.timer, llc_conn_pf_cycle_tmr_cb,
838                         (unsigned long)sk);
839         llc->pf_cycle_timer.expire         = sysctl_llc2_p_timeout;
840
841         setup_timer(&llc->rej_sent_timer.timer, llc_conn_rej_tmr_cb,
842                         (unsigned long)sk);
843         llc->rej_sent_timer.expire         = sysctl_llc2_rej_timeout;
844
845         setup_timer(&llc->busy_state_timer.timer, llc_conn_busy_tmr_cb,
846                         (unsigned long)sk);
847         llc->busy_state_timer.expire         = sysctl_llc2_busy_timeout;
848
849         llc->n2 = 2;   /* max retransmit */
850         llc->k  = 2;   /* tx win size, will adjust dynam */
851         llc->rw = 128; /* rx win size (opt and equal to
852                         * tx_win of remote LLC) */
853         skb_queue_head_init(&llc->pdu_unack_q);
854         sk->sk_backlog_rcv = llc_backlog_rcv;
855 }
856
857 /**
858  *      llc_sk_alloc - Allocates LLC sock
859  *      @family: upper layer protocol family
860  *      @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
861  *
862  *      Allocates a LLC sock and initializes it. Returns the new LLC sock
863  *      or %NULL if there's no memory available for one
864  */
865 struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot)
866 {
867         struct sock *sk = sk_alloc(net, family, priority, prot);
868
869         if (!sk)
870                 goto out;
871         llc_sk_init(sk);
872         sock_init_data(NULL, sk);
873 #ifdef LLC_REFCNT_DEBUG
874         atomic_inc(&llc_sock_nr);
875         printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk,
876                 __func__, atomic_read(&llc_sock_nr));
877 #endif
878 out:
879         return sk;
880 }
881
882 /**
883  *      llc_sk_free - Frees a LLC socket
884  *      @sk - socket to free
885  *
886  *      Frees a LLC socket
887  */
888 void llc_sk_free(struct sock *sk)
889 {
890         struct llc_sock *llc = llc_sk(sk);
891
892         llc->state = LLC_CONN_OUT_OF_SVC;
893         /* Stop all (possibly) running timers */
894         llc_conn_ac_stop_all_timers(sk, NULL);
895 #ifdef DEBUG_LLC_CONN_ALLOC
896         printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __func__,
897                 skb_queue_len(&llc->pdu_unack_q),
898                 skb_queue_len(&sk->sk_write_queue));
899 #endif
900         skb_queue_purge(&sk->sk_receive_queue);
901         skb_queue_purge(&sk->sk_write_queue);
902         skb_queue_purge(&llc->pdu_unack_q);
903 #ifdef LLC_REFCNT_DEBUG
904         if (atomic_read(&sk->sk_refcnt) != 1) {
905                 printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
906                         sk, __func__, atomic_read(&sk->sk_refcnt));
907                 printk(KERN_DEBUG "%d LLC sockets are still alive\n",
908                         atomic_read(&llc_sock_nr));
909         } else {
910                 atomic_dec(&llc_sock_nr);
911                 printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk,
912                         __func__, atomic_read(&llc_sock_nr));
913         }
914 #endif
915         sock_put(sk);
916 }
917
918 /**
919  *      llc_sk_reset - resets a connection
920  *      @sk: LLC socket to reset
921  *
922  *      Resets a connection to the out of service state. Stops its timers
923  *      and frees any frames in the queues of the connection.
924  */
925 void llc_sk_reset(struct sock *sk)
926 {
927         struct llc_sock *llc = llc_sk(sk);
928
929         llc_conn_ac_stop_all_timers(sk, NULL);
930         skb_queue_purge(&sk->sk_write_queue);
931         skb_queue_purge(&llc->pdu_unack_q);
932         llc->remote_busy_flag   = 0;
933         llc->cause_flag         = 0;
934         llc->retry_count        = 0;
935         llc_conn_set_p_flag(sk, 0);
936         llc->f_flag             = 0;
937         llc->s_flag             = 0;
938         llc->ack_pf             = 0;
939         llc->first_pdu_Ns       = 0;
940         llc->ack_must_be_send   = 0;
941         llc->dec_step           = 1;
942         llc->inc_cntr           = 2;
943         llc->dec_cntr           = 2;
944         llc->X                  = 0;
945         llc->failed_data_req    = 0 ;
946         llc->last_nr            = 0;
947 }