[NET]: Make packet reception network namespace safe
[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", __FUNCTION__);
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                                __FUNCTION__);
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", __FUNCTION__);
136                 kfree_skb(skb);
137                 break;
138         default:
139                 if (ev->ind_prim) {
140                         printk(KERN_INFO "%s: received unknown %d prim!\n",
141                                 __FUNCTION__, 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", __FUNCTION__);
183                 break;
184         default:
185                 if (ev->cfm_prim) {
186                         printk(KERN_INFO "%s: received unknown %d prim!\n",
187                                         __FUNCTION__, 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                 if (skb)
336                         kfree_skb(skb);
337                 nbr_acked++;
338         }
339 out:
340         *how_many_unacked = skb_queue_len(&llc->pdu_unack_q);
341         return nbr_acked;
342 }
343
344 /**
345  *      llc_conn_send_pdus - Sends queued PDUs
346  *      @sk: active connection
347  *
348  *      Sends queued pdus to MAC layer for transmission.
349  */
350 static void llc_conn_send_pdus(struct sock *sk)
351 {
352         struct sk_buff *skb;
353
354         while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
355                 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
356
357                 if (LLC_PDU_TYPE_IS_I(pdu) &&
358                     !(skb->dev->flags & IFF_LOOPBACK)) {
359                         struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
360
361                         skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
362                         if (!skb2)
363                                 break;
364                         skb = skb2;
365                 }
366                 dev_queue_xmit(skb);
367         }
368 }
369
370 /**
371  *      llc_conn_service - finds transition and changes state of connection
372  *      @sk: connection
373  *      @skb: happened event
374  *
375  *      This function finds transition that matches with happened event, then
376  *      executes related actions and finally changes state of connection.
377  *      Returns 0 for success, 1 for failure.
378  */
379 static int llc_conn_service(struct sock *sk, struct sk_buff *skb)
380 {
381         int rc = 1;
382         struct llc_sock *llc = llc_sk(sk);
383         struct llc_conn_state_trans *trans;
384
385         if (llc->state > NBR_CONN_STATES)
386                 goto out;
387         rc = 0;
388         trans = llc_qualify_conn_ev(sk, skb);
389         if (trans) {
390                 rc = llc_exec_conn_trans_actions(sk, trans, skb);
391                 if (!rc && trans->next_state != NO_STATE_CHANGE) {
392                         llc->state = trans->next_state;
393                         if (!llc_data_accept_state(llc->state))
394                                 sk->sk_state_change(sk);
395                 }
396         }
397 out:
398         return rc;
399 }
400
401 /**
402  *      llc_qualify_conn_ev - finds transition for event
403  *      @sk: connection
404  *      @skb: happened event
405  *
406  *      This function finds transition that matches with happened event.
407  *      Returns pointer to found transition on success, %NULL otherwise.
408  */
409 static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
410                                                         struct sk_buff *skb)
411 {
412         struct llc_conn_state_trans **next_trans;
413         llc_conn_ev_qfyr_t *next_qualifier;
414         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
415         struct llc_sock *llc = llc_sk(sk);
416         struct llc_conn_state *curr_state =
417                                         &llc_conn_state_table[llc->state - 1];
418
419         /* search thru events for this state until
420          * list exhausted or until no more
421          */
422         for (next_trans = curr_state->transitions +
423                 llc_find_offset(llc->state - 1, ev->type);
424              (*next_trans)->ev; next_trans++) {
425                 if (!((*next_trans)->ev)(sk, skb)) {
426                         /* got POSSIBLE event match; the event may require
427                          * qualification based on the values of a number of
428                          * state flags; if all qualifications are met (i.e.,
429                          * if all qualifying functions return success, or 0,
430                          * then this is THE event we're looking for
431                          */
432                         for (next_qualifier = (*next_trans)->ev_qualifiers;
433                              next_qualifier && *next_qualifier &&
434                              !(*next_qualifier)(sk, skb); next_qualifier++)
435                                 /* nothing */;
436                         if (!next_qualifier || !*next_qualifier)
437                                 /* all qualifiers executed successfully; this is
438                                  * our transition; return it so we can perform
439                                  * the associated actions & change the state
440                                  */
441                                 return *next_trans;
442                 }
443         }
444         return NULL;
445 }
446
447 /**
448  *      llc_exec_conn_trans_actions - executes related actions
449  *      @sk: connection
450  *      @trans: transition that it's actions must be performed
451  *      @skb: event
452  *
453  *      Executes actions that is related to happened event. Returns 0 for
454  *      success, 1 to indicate failure of at least one action.
455  */
456 static int llc_exec_conn_trans_actions(struct sock *sk,
457                                        struct llc_conn_state_trans *trans,
458                                        struct sk_buff *skb)
459 {
460         int rc = 0;
461         llc_conn_action_t *next_action;
462
463         for (next_action = trans->ev_actions;
464              next_action && *next_action; next_action++) {
465                 int rc2 = (*next_action)(sk, skb);
466
467                 if (rc2 == 2) {
468                         rc = rc2;
469                         break;
470                 } else if (rc2)
471                         rc = 1;
472         }
473         return rc;
474 }
475
476 /**
477  *      __llc_lookup_established - Finds connection for the remote/local sap/mac
478  *      @sap: SAP
479  *      @daddr: address of remote LLC (MAC + SAP)
480  *      @laddr: address of local LLC (MAC + SAP)
481  *
482  *      Search connection list of the SAP and finds connection using the remote
483  *      mac, remote sap, local mac, and local sap. Returns pointer for
484  *      connection found, %NULL otherwise.
485  *      Caller has to make sure local_bh is disabled.
486  */
487 static struct sock *__llc_lookup_established(struct llc_sap *sap,
488                                              struct llc_addr *daddr,
489                                              struct llc_addr *laddr)
490 {
491         struct sock *rc;
492         struct hlist_node *node;
493
494         read_lock(&sap->sk_list.lock);
495         sk_for_each(rc, node, &sap->sk_list.list) {
496                 struct llc_sock *llc = llc_sk(rc);
497
498                 if (llc->laddr.lsap == laddr->lsap &&
499                     llc->daddr.lsap == daddr->lsap &&
500                     llc_mac_match(llc->laddr.mac, laddr->mac) &&
501                     llc_mac_match(llc->daddr.mac, daddr->mac)) {
502                         sock_hold(rc);
503                         goto found;
504                 }
505         }
506         rc = NULL;
507 found:
508         read_unlock(&sap->sk_list.lock);
509         return rc;
510 }
511
512 struct sock *llc_lookup_established(struct llc_sap *sap,
513                                     struct llc_addr *daddr,
514                                     struct llc_addr *laddr)
515 {
516         struct sock *sk;
517
518         local_bh_disable();
519         sk = __llc_lookup_established(sap, daddr, laddr);
520         local_bh_enable();
521         return sk;
522 }
523
524 /**
525  *      llc_lookup_listener - Finds listener for local MAC + SAP
526  *      @sap: SAP
527  *      @laddr: address of local LLC (MAC + SAP)
528  *
529  *      Search connection list of the SAP and finds connection listening on
530  *      local mac, and local sap. Returns pointer for parent socket found,
531  *      %NULL otherwise.
532  *      Caller has to make sure local_bh is disabled.
533  */
534 static struct sock *llc_lookup_listener(struct llc_sap *sap,
535                                         struct llc_addr *laddr)
536 {
537         struct sock *rc;
538         struct hlist_node *node;
539
540         read_lock(&sap->sk_list.lock);
541         sk_for_each(rc, node, &sap->sk_list.list) {
542                 struct llc_sock *llc = llc_sk(rc);
543
544                 if (rc->sk_type == SOCK_STREAM && rc->sk_state == TCP_LISTEN &&
545                     llc->laddr.lsap == laddr->lsap &&
546                     (llc_mac_match(llc->laddr.mac, laddr->mac) ||
547                      llc_mac_null(llc->laddr.mac))) {
548                         sock_hold(rc);
549                         goto found;
550                 }
551         }
552         rc = NULL;
553 found:
554         read_unlock(&sap->sk_list.lock);
555         return rc;
556 }
557
558 static struct sock *__llc_lookup(struct llc_sap *sap,
559                                  struct llc_addr *daddr,
560                                  struct llc_addr *laddr)
561 {
562         struct sock *sk = __llc_lookup_established(sap, daddr, laddr);
563
564         return sk ? : llc_lookup_listener(sap, laddr);
565 }
566
567 /**
568  *      llc_data_accept_state - designates if in this state data can be sent.
569  *      @state: state of connection.
570  *
571  *      Returns 0 if data can be sent, 1 otherwise.
572  */
573 u8 llc_data_accept_state(u8 state)
574 {
575         return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY &&
576                state != LLC_CONN_STATE_REJ;
577 }
578
579 /**
580  *      llc_find_next_offset - finds offset for next category of transitions
581  *      @state: state table.
582  *      @offset: start offset.
583  *
584  *      Finds offset of next category of transitions in transition table.
585  *      Returns the start index of next category.
586  */
587 static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset)
588 {
589         u16 cnt = 0;
590         struct llc_conn_state_trans **next_trans;
591
592         for (next_trans = state->transitions + offset;
593              (*next_trans)->ev; next_trans++)
594                 ++cnt;
595         return cnt;
596 }
597
598 /**
599  *      llc_build_offset_table - builds offset table of connection
600  *
601  *      Fills offset table of connection state transition table
602  *      (llc_offset_table).
603  */
604 void __init llc_build_offset_table(void)
605 {
606         struct llc_conn_state *curr_state;
607         int state, ev_type, next_offset;
608
609         for (state = 0; state < NBR_CONN_STATES; state++) {
610                 curr_state = &llc_conn_state_table[state];
611                 next_offset = 0;
612                 for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) {
613                         llc_offset_table[state][ev_type] = next_offset;
614                         next_offset += llc_find_next_offset(curr_state,
615                                                             next_offset) + 1;
616                 }
617         }
618 }
619
620 /**
621  *      llc_find_offset - finds start offset of category of transitions
622  *      @state: state of connection
623  *      @ev_type: type of happened event
624  *
625  *      Finds start offset of desired category of transitions. Returns the
626  *      desired start offset.
627  */
628 static int llc_find_offset(int state, int ev_type)
629 {
630         int rc = 0;
631         /* at this stage, llc_offset_table[..][2] is not important. it is for
632          * init_pf_cycle and I don't know what is it.
633          */
634         switch (ev_type) {
635         case LLC_CONN_EV_TYPE_PRIM:
636                 rc = llc_offset_table[state][0]; break;
637         case LLC_CONN_EV_TYPE_PDU:
638                 rc = llc_offset_table[state][4]; break;
639         case LLC_CONN_EV_TYPE_SIMPLE:
640                 rc = llc_offset_table[state][1]; break;
641         case LLC_CONN_EV_TYPE_P_TMR:
642         case LLC_CONN_EV_TYPE_ACK_TMR:
643         case LLC_CONN_EV_TYPE_REJ_TMR:
644         case LLC_CONN_EV_TYPE_BUSY_TMR:
645                 rc = llc_offset_table[state][3]; break;
646         }
647         return rc;
648 }
649
650 /**
651  *      llc_sap_add_socket - adds a socket to a SAP
652  *      @sap: SAP
653  *      @sk: socket
654  *
655  *      This function adds a socket to sk_list of a SAP.
656  */
657 void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
658 {
659         llc_sap_hold(sap);
660         write_lock_bh(&sap->sk_list.lock);
661         llc_sk(sk)->sap = sap;
662         sk_add_node(sk, &sap->sk_list.list);
663         write_unlock_bh(&sap->sk_list.lock);
664 }
665
666 /**
667  *      llc_sap_remove_socket - removes a socket from SAP
668  *      @sap: SAP
669  *      @sk: socket
670  *
671  *      This function removes a connection from sk_list.list of a SAP if
672  *      the connection was in this list.
673  */
674 void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
675 {
676         write_lock_bh(&sap->sk_list.lock);
677         sk_del_node_init(sk);
678         write_unlock_bh(&sap->sk_list.lock);
679         llc_sap_put(sap);
680 }
681
682 /**
683  *      llc_conn_rcv - sends received pdus to the connection state machine
684  *      @sk: current connection structure.
685  *      @skb: received frame.
686  *
687  *      Sends received pdus to the connection state machine.
688  */
689 static int llc_conn_rcv(struct sock* sk, struct sk_buff *skb)
690 {
691         struct llc_conn_state_ev *ev = llc_conn_ev(skb);
692
693         ev->type   = LLC_CONN_EV_TYPE_PDU;
694         ev->reason = 0;
695         return llc_conn_state_process(sk, skb);
696 }
697
698 static struct sock *llc_create_incoming_sock(struct sock *sk,
699                                              struct net_device *dev,
700                                              struct llc_addr *saddr,
701                                              struct llc_addr *daddr)
702 {
703         struct sock *newsk = llc_sk_alloc(sk->sk_net, sk->sk_family, GFP_ATOMIC,
704                                           sk->sk_prot);
705         struct llc_sock *newllc, *llc = llc_sk(sk);
706
707         if (!newsk)
708                 goto out;
709         newllc = llc_sk(newsk);
710         memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
711         memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
712         newllc->dev = dev;
713         dev_hold(dev);
714         llc_sap_add_socket(llc->sap, newsk);
715         llc_sap_hold(llc->sap);
716 out:
717         return newsk;
718 }
719
720 void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
721 {
722         struct llc_addr saddr, daddr;
723         struct sock *sk;
724
725         llc_pdu_decode_sa(skb, saddr.mac);
726         llc_pdu_decode_ssap(skb, &saddr.lsap);
727         llc_pdu_decode_da(skb, daddr.mac);
728         llc_pdu_decode_dsap(skb, &daddr.lsap);
729
730         sk = __llc_lookup(sap, &saddr, &daddr);
731         if (!sk)
732                 goto drop;
733
734         bh_lock_sock(sk);
735         /*
736          * This has to be done here and not at the upper layer ->accept
737          * method because of the way the PROCOM state machine works:
738          * it needs to set several state variables (see, for instance,
739          * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
740          * the originator of the new connection, and this state has to be
741          * in the newly created struct sock private area. -acme
742          */
743         if (unlikely(sk->sk_state == TCP_LISTEN)) {
744                 struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
745                                                               &saddr, &daddr);
746                 if (!newsk)
747                         goto drop_unlock;
748                 skb_set_owner_r(skb, newsk);
749         } else {
750                 /*
751                  * Can't be skb_set_owner_r, this will be done at the
752                  * llc_conn_state_process function, later on, when we will use
753                  * skb_queue_rcv_skb to send it to upper layers, this is
754                  * another trick required to cope with how the PROCOM state
755                  * machine works. -acme
756                  */
757                 skb->sk = sk;
758         }
759         if (!sock_owned_by_user(sk))
760                 llc_conn_rcv(sk, skb);
761         else {
762                 dprintk("%s: adding to backlog...\n", __FUNCTION__);
763                 llc_set_backlog_type(skb, LLC_PACKET);
764                 sk_add_backlog(sk, skb);
765         }
766 out:
767         bh_unlock_sock(sk);
768         sock_put(sk);
769         return;
770 drop:
771         kfree_skb(skb);
772         return;
773 drop_unlock:
774         kfree_skb(skb);
775         goto out;
776 }
777
778 #undef LLC_REFCNT_DEBUG
779 #ifdef LLC_REFCNT_DEBUG
780 static atomic_t llc_sock_nr;
781 #endif
782
783 /**
784  *      llc_backlog_rcv - Processes rx frames and expired timers.
785  *      @sk: LLC sock (p8022 connection)
786  *      @skb: queued rx frame or event
787  *
788  *      This function processes frames that has received and timers that has
789  *      expired during sending an I pdu (refer to data_req_handler).  frames
790  *      queue by llc_rcv function (llc_mac.c) and timers queue by timer
791  *      callback functions(llc_c_ac.c).
792  */
793 static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
794 {
795         int rc = 0;
796         struct llc_sock *llc = llc_sk(sk);
797
798         if (likely(llc_backlog_type(skb) == LLC_PACKET)) {
799                 if (likely(llc->state > 1)) /* not closed */
800                         rc = llc_conn_rcv(sk, skb);
801                 else
802                         goto out_kfree_skb;
803         } else if (llc_backlog_type(skb) == LLC_EVENT) {
804                 /* timer expiration event */
805                 if (likely(llc->state > 1))  /* not closed */
806                         rc = llc_conn_state_process(sk, skb);
807                 else
808                         goto out_kfree_skb;
809         } else {
810                 printk(KERN_ERR "%s: invalid skb in backlog\n", __FUNCTION__);
811                 goto out_kfree_skb;
812         }
813 out:
814         return rc;
815 out_kfree_skb:
816         kfree_skb(skb);
817         goto out;
818 }
819
820 /**
821  *     llc_sk_init - Initializes a socket with default llc values.
822  *     @sk: socket to initialize.
823  *
824  *     Initializes a socket with default llc values.
825  */
826 static void llc_sk_init(struct sock* sk)
827 {
828         struct llc_sock *llc = llc_sk(sk);
829
830         llc->state    = LLC_CONN_STATE_ADM;
831         llc->inc_cntr = llc->dec_cntr = 2;
832         llc->dec_step = llc->connect_step = 1;
833
834         init_timer(&llc->ack_timer.timer);
835         llc->ack_timer.expire         = sysctl_llc2_ack_timeout;
836         llc->ack_timer.timer.data     = (unsigned long)sk;
837         llc->ack_timer.timer.function = llc_conn_ack_tmr_cb;
838
839         init_timer(&llc->pf_cycle_timer.timer);
840         llc->pf_cycle_timer.expire         = sysctl_llc2_p_timeout;
841         llc->pf_cycle_timer.timer.data     = (unsigned long)sk;
842         llc->pf_cycle_timer.timer.function = llc_conn_pf_cycle_tmr_cb;
843
844         init_timer(&llc->rej_sent_timer.timer);
845         llc->rej_sent_timer.expire         = sysctl_llc2_rej_timeout;
846         llc->rej_sent_timer.timer.data     = (unsigned long)sk;
847         llc->rej_sent_timer.timer.function = llc_conn_rej_tmr_cb;
848
849         init_timer(&llc->busy_state_timer.timer);
850         llc->busy_state_timer.expire         = sysctl_llc2_busy_timeout;
851         llc->busy_state_timer.timer.data     = (unsigned long)sk;
852         llc->busy_state_timer.timer.function = llc_conn_busy_tmr_cb;
853
854         llc->n2 = 2;   /* max retransmit */
855         llc->k  = 2;   /* tx win size, will adjust dynam */
856         llc->rw = 128; /* rx win size (opt and equal to
857                         * tx_win of remote LLC) */
858         skb_queue_head_init(&llc->pdu_unack_q);
859         sk->sk_backlog_rcv = llc_backlog_rcv;
860 }
861
862 /**
863  *      llc_sk_alloc - Allocates LLC sock
864  *      @family: upper layer protocol family
865  *      @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
866  *
867  *      Allocates a LLC sock and initializes it. Returns the new LLC sock
868  *      or %NULL if there's no memory available for one
869  */
870 struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot)
871 {
872         struct sock *sk = sk_alloc(net, family, priority, prot, 1);
873
874         if (!sk)
875                 goto out;
876         llc_sk_init(sk);
877         sock_init_data(NULL, sk);
878 #ifdef LLC_REFCNT_DEBUG
879         atomic_inc(&llc_sock_nr);
880         printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk,
881                 __FUNCTION__, atomic_read(&llc_sock_nr));
882 #endif
883 out:
884         return sk;
885 }
886
887 /**
888  *      llc_sk_free - Frees a LLC socket
889  *      @sk - socket to free
890  *
891  *      Frees a LLC socket
892  */
893 void llc_sk_free(struct sock *sk)
894 {
895         struct llc_sock *llc = llc_sk(sk);
896
897         llc->state = LLC_CONN_OUT_OF_SVC;
898         /* Stop all (possibly) running timers */
899         llc_conn_ac_stop_all_timers(sk, NULL);
900 #ifdef DEBUG_LLC_CONN_ALLOC
901         printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __FUNCTION__,
902                 skb_queue_len(&llc->pdu_unack_q),
903                 skb_queue_len(&sk->sk_write_queue));
904 #endif
905         skb_queue_purge(&sk->sk_receive_queue);
906         skb_queue_purge(&sk->sk_write_queue);
907         skb_queue_purge(&llc->pdu_unack_q);
908 #ifdef LLC_REFCNT_DEBUG
909         if (atomic_read(&sk->sk_refcnt) != 1) {
910                 printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
911                         sk, __FUNCTION__, atomic_read(&sk->sk_refcnt));
912                 printk(KERN_DEBUG "%d LLC sockets are still alive\n",
913                         atomic_read(&llc_sock_nr));
914         } else {
915                 atomic_dec(&llc_sock_nr);
916                 printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk,
917                         __FUNCTION__, atomic_read(&llc_sock_nr));
918         }
919 #endif
920         sock_put(sk);
921 }
922
923 /**
924  *      llc_sk_reset - resets a connection
925  *      @sk: LLC socket to reset
926  *
927  *      Resets a connection to the out of service state. Stops its timers
928  *      and frees any frames in the queues of the connection.
929  */
930 void llc_sk_reset(struct sock *sk)
931 {
932         struct llc_sock *llc = llc_sk(sk);
933
934         llc_conn_ac_stop_all_timers(sk, NULL);
935         skb_queue_purge(&sk->sk_write_queue);
936         skb_queue_purge(&llc->pdu_unack_q);
937         llc->remote_busy_flag   = 0;
938         llc->cause_flag         = 0;
939         llc->retry_count        = 0;
940         llc_conn_set_p_flag(sk, 0);
941         llc->f_flag             = 0;
942         llc->s_flag             = 0;
943         llc->ack_pf             = 0;
944         llc->first_pdu_Ns       = 0;
945         llc->ack_must_be_send   = 0;
946         llc->dec_step           = 1;
947         llc->inc_cntr           = 2;
948         llc->dec_cntr           = 2;
949         llc->X                  = 0;
950         llc->failed_data_req    = 0 ;
951         llc->last_nr            = 0;
952 }