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.h>
18 #include <net/llc_c_ac.h>
19 #include <net/llc_c_ev.h>
20 #include <net/llc_c_st.h>
21 #include <net/llc_conn.h>
22 #include <net/llc_pdu.h>
23 #include <net/llc_sap.h>
24 #include <net/sock.h>
25 #include <net/tcp_states.h>
26
27 #if 0
28 #define dprintk(args...) printk(KERN_DEBUG args)
29 #else
30 #define dprintk(args...)
31 #endif
32
33 static int llc_find_offset(int state, int ev_type);
34 static void llc_conn_send_pdus(struct sock *sk);
35 static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
36 static int llc_exec_conn_trans_actions(struct sock *sk,
37 const struct llc_conn_state_trans *trans,
38 struct sk_buff *ev);
39 static const struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
40 struct sk_buff *skb);
41
42 /* Offset table on connection states transition diagram */
43 static int llc_offset_table[NBR_CONN_STATES][NBR_CONN_EV];
44
45 int sysctl_llc2_ack_timeout = LLC2_ACK_TIME * HZ;
46 int sysctl_llc2_p_timeout = LLC2_P_TIME * HZ;
47 int sysctl_llc2_rej_timeout = LLC2_REJ_TIME * HZ;
48 int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ;
49
50 /**
51 * llc_conn_state_process - sends event to connection state machine
52 * @sk: connection
53 * @skb: occurred event
54 *
55 * Sends an event to connection state machine. After processing event
56 * (executing it's actions and changing state), upper layer will be
57 * indicated or confirmed, if needed. Returns 0 for success, 1 for
58 * failure. The socket lock has to be held before calling this function.
59 *
60 * This function always consumes a reference to the skb.
61 */
llc_conn_state_process(struct sock * sk,struct sk_buff * skb)62 int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
63 {
64 int rc;
65 struct llc_sock *llc = llc_sk(skb->sk);
66 struct llc_conn_state_ev *ev = llc_conn_ev(skb);
67
68 ev->ind_prim = ev->cfm_prim = 0;
69 /*
70 * Send event to state machine
71 */
72 rc = llc_conn_service(skb->sk, skb);
73 if (unlikely(rc != 0)) {
74 printk(KERN_ERR "%s: llc_conn_service failed\n", __func__);
75 goto out_skb_put;
76 }
77
78 switch (ev->ind_prim) {
79 case LLC_DATA_PRIM:
80 skb_get(skb);
81 llc_save_primitive(sk, skb, LLC_DATA_PRIM);
82 if (unlikely(sock_queue_rcv_skb(sk, skb))) {
83 /*
84 * shouldn't happen
85 */
86 printk(KERN_ERR "%s: sock_queue_rcv_skb failed!\n",
87 __func__);
88 kfree_skb(skb);
89 }
90 break;
91 case LLC_CONN_PRIM:
92 /*
93 * Can't be sock_queue_rcv_skb, because we have to leave the
94 * skb->sk pointing to the newly created struct sock in
95 * llc_conn_handler. -acme
96 */
97 skb_get(skb);
98 skb_queue_tail(&sk->sk_receive_queue, skb);
99 sk->sk_state_change(sk);
100 break;
101 case LLC_DISC_PRIM:
102 sock_hold(sk);
103 if (sk->sk_type == SOCK_STREAM &&
104 sk->sk_state == TCP_ESTABLISHED) {
105 sk->sk_shutdown = SHUTDOWN_MASK;
106 sk->sk_socket->state = SS_UNCONNECTED;
107 sk->sk_state = TCP_CLOSE;
108 if (!sock_flag(sk, SOCK_DEAD)) {
109 sock_set_flag(sk, SOCK_DEAD);
110 sk->sk_state_change(sk);
111 }
112 }
113 sock_put(sk);
114 break;
115 case LLC_RESET_PRIM:
116 /*
117 * FIXME:
118 * RESET is not being notified to upper layers for now
119 */
120 printk(KERN_INFO "%s: received a reset ind!\n", __func__);
121 break;
122 default:
123 if (ev->ind_prim)
124 printk(KERN_INFO "%s: received unknown %d prim!\n",
125 __func__, ev->ind_prim);
126 /* No indication */
127 break;
128 }
129
130 switch (ev->cfm_prim) {
131 case LLC_DATA_PRIM:
132 if (!llc_data_accept_state(llc->state))
133 sk->sk_write_space(sk);
134 else
135 rc = llc->failed_data_req = 1;
136 break;
137 case LLC_CONN_PRIM:
138 if (sk->sk_type == SOCK_STREAM &&
139 sk->sk_state == TCP_SYN_SENT) {
140 if (ev->status) {
141 sk->sk_socket->state = SS_UNCONNECTED;
142 sk->sk_state = TCP_CLOSE;
143 } else {
144 sk->sk_socket->state = SS_CONNECTED;
145 sk->sk_state = TCP_ESTABLISHED;
146 }
147 sk->sk_state_change(sk);
148 }
149 break;
150 case LLC_DISC_PRIM:
151 sock_hold(sk);
152 if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSING) {
153 sk->sk_socket->state = SS_UNCONNECTED;
154 sk->sk_state = TCP_CLOSE;
155 sk->sk_state_change(sk);
156 }
157 sock_put(sk);
158 break;
159 case LLC_RESET_PRIM:
160 /*
161 * FIXME:
162 * RESET is not being notified to upper layers for now
163 */
164 printk(KERN_INFO "%s: received a reset conf!\n", __func__);
165 break;
166 default:
167 if (ev->cfm_prim)
168 printk(KERN_INFO "%s: received unknown %d prim!\n",
169 __func__, ev->cfm_prim);
170 /* No confirmation */
171 break;
172 }
173 out_skb_put:
174 kfree_skb(skb);
175 return rc;
176 }
177
llc_conn_send_pdu(struct sock * sk,struct sk_buff * skb)178 void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
179 {
180 /* queue PDU to send to MAC layer */
181 skb_queue_tail(&sk->sk_write_queue, skb);
182 llc_conn_send_pdus(sk);
183 }
184
185 /**
186 * llc_conn_rtn_pdu - sends received data pdu to upper layer
187 * @sk: Active connection
188 * @skb: Received data frame
189 *
190 * Sends received data pdu to upper layer (by using indicate function).
191 * Prepares service parameters (prim and prim_data). calling indication
192 * function will be done in llc_conn_state_process.
193 */
llc_conn_rtn_pdu(struct sock * sk,struct sk_buff * skb)194 void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb)
195 {
196 struct llc_conn_state_ev *ev = llc_conn_ev(skb);
197
198 ev->ind_prim = LLC_DATA_PRIM;
199 }
200
201 /**
202 * llc_conn_resend_i_pdu_as_cmd - resend all all unacknowledged I PDUs
203 * @sk: active connection
204 * @nr: NR
205 * @first_p_bit: p_bit value of first pdu
206 *
207 * Resend all unacknowledged I PDUs, starting with the NR; send first as
208 * command PDU with P bit equal first_p_bit; if more than one send
209 * subsequent as command PDUs with P bit equal zero (0).
210 */
llc_conn_resend_i_pdu_as_cmd(struct sock * sk,u8 nr,u8 first_p_bit)211 void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit)
212 {
213 struct sk_buff *skb;
214 struct llc_pdu_sn *pdu;
215 u16 nbr_unack_pdus;
216 struct llc_sock *llc;
217 u8 howmany_resend = 0;
218
219 llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
220 if (!nbr_unack_pdus)
221 goto out;
222 /*
223 * Process unack PDUs only if unack queue is not empty; remove
224 * appropriate PDUs, fix them up, and put them on mac_pdu_q.
225 */
226 llc = llc_sk(sk);
227
228 while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
229 pdu = llc_pdu_sn_hdr(skb);
230 llc_pdu_set_cmd_rsp(skb, LLC_PDU_CMD);
231 llc_pdu_set_pf_bit(skb, first_p_bit);
232 skb_queue_tail(&sk->sk_write_queue, skb);
233 first_p_bit = 0;
234 llc->vS = LLC_I_GET_NS(pdu);
235 howmany_resend++;
236 }
237 if (howmany_resend > 0)
238 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
239 /* any PDUs to re-send are queued up; start sending to MAC */
240 llc_conn_send_pdus(sk);
241 out:;
242 }
243
244 /**
245 * llc_conn_resend_i_pdu_as_rsp - Resend all unacknowledged I PDUs
246 * @sk: active connection.
247 * @nr: NR
248 * @first_f_bit: f_bit value of first pdu.
249 *
250 * Resend all unacknowledged I PDUs, starting with the NR; send first as
251 * response PDU with F bit equal first_f_bit; if more than one send
252 * subsequent as response PDUs with F bit equal zero (0).
253 */
llc_conn_resend_i_pdu_as_rsp(struct sock * sk,u8 nr,u8 first_f_bit)254 void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit)
255 {
256 struct sk_buff *skb;
257 u16 nbr_unack_pdus;
258 struct llc_sock *llc = llc_sk(sk);
259 u8 howmany_resend = 0;
260
261 llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
262 if (!nbr_unack_pdus)
263 goto out;
264 /*
265 * Process unack PDUs only if unack queue is not empty; remove
266 * appropriate PDUs, fix them up, and put them on mac_pdu_q
267 */
268 while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
269 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
270
271 llc_pdu_set_cmd_rsp(skb, LLC_PDU_RSP);
272 llc_pdu_set_pf_bit(skb, first_f_bit);
273 skb_queue_tail(&sk->sk_write_queue, skb);
274 first_f_bit = 0;
275 llc->vS = LLC_I_GET_NS(pdu);
276 howmany_resend++;
277 }
278 if (howmany_resend > 0)
279 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
280 /* any PDUs to re-send are queued up; start sending to MAC */
281 llc_conn_send_pdus(sk);
282 out:;
283 }
284
285 /**
286 * llc_conn_remove_acked_pdus - Removes acknowledged pdus from tx queue
287 * @sk: active connection
288 * @nr: NR
289 * @how_many_unacked: size of pdu_unack_q after removing acked pdus
290 *
291 * Removes acknowledged pdus from transmit queue (pdu_unack_q). Returns
292 * the number of pdus that removed from queue.
293 */
llc_conn_remove_acked_pdus(struct sock * sk,u8 nr,u16 * how_many_unacked)294 int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked)
295 {
296 int pdu_pos, i;
297 struct sk_buff *skb;
298 struct llc_pdu_sn *pdu;
299 int nbr_acked = 0;
300 struct llc_sock *llc = llc_sk(sk);
301 int q_len = skb_queue_len(&llc->pdu_unack_q);
302
303 if (!q_len)
304 goto out;
305 skb = skb_peek(&llc->pdu_unack_q);
306 pdu = llc_pdu_sn_hdr(skb);
307
308 /* finding position of last acked pdu in queue */
309 pdu_pos = ((int)LLC_2_SEQ_NBR_MODULO + (int)nr -
310 (int)LLC_I_GET_NS(pdu)) % LLC_2_SEQ_NBR_MODULO;
311
312 for (i = 0; i < pdu_pos && i < q_len; i++) {
313 skb = skb_dequeue(&llc->pdu_unack_q);
314 kfree_skb(skb);
315 nbr_acked++;
316 }
317 out:
318 *how_many_unacked = skb_queue_len(&llc->pdu_unack_q);
319 return nbr_acked;
320 }
321
322 /**
323 * llc_conn_send_pdus - Sends queued PDUs
324 * @sk: active connection
325 *
326 * Sends queued pdus to MAC layer for transmission.
327 */
llc_conn_send_pdus(struct sock * sk)328 static void llc_conn_send_pdus(struct sock *sk)
329 {
330 struct sk_buff *skb;
331
332 while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
333 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
334
335 if (LLC_PDU_TYPE_IS_I(pdu) &&
336 !(skb->dev->flags & IFF_LOOPBACK)) {
337 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
338
339 skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
340 if (!skb2)
341 break;
342 skb = skb2;
343 }
344 dev_queue_xmit(skb);
345 }
346 }
347
348 /**
349 * llc_conn_service - finds transition and changes state of connection
350 * @sk: connection
351 * @skb: happened event
352 *
353 * This function finds transition that matches with happened event, then
354 * executes related actions and finally changes state of connection.
355 * Returns 0 for success, 1 for failure.
356 */
llc_conn_service(struct sock * sk,struct sk_buff * skb)357 static int llc_conn_service(struct sock *sk, struct sk_buff *skb)
358 {
359 const struct llc_conn_state_trans *trans;
360 struct llc_sock *llc = llc_sk(sk);
361 int rc = 1;
362
363 if (llc->state > NBR_CONN_STATES)
364 goto out;
365 rc = 0;
366 trans = llc_qualify_conn_ev(sk, skb);
367 if (trans) {
368 rc = llc_exec_conn_trans_actions(sk, trans, skb);
369 if (!rc && trans->next_state != NO_STATE_CHANGE) {
370 llc->state = trans->next_state;
371 if (!llc_data_accept_state(llc->state))
372 sk->sk_state_change(sk);
373 }
374 }
375 out:
376 return rc;
377 }
378
379 /**
380 * llc_qualify_conn_ev - finds transition for event
381 * @sk: connection
382 * @skb: happened event
383 *
384 * This function finds transition that matches with happened event.
385 * Returns pointer to found transition on success, %NULL otherwise.
386 */
llc_qualify_conn_ev(struct sock * sk,struct sk_buff * skb)387 static const struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
388 struct sk_buff *skb)
389 {
390 const struct llc_conn_state_trans **next_trans;
391 const llc_conn_ev_qfyr_t *next_qualifier;
392 struct llc_conn_state_ev *ev = llc_conn_ev(skb);
393 struct llc_sock *llc = llc_sk(sk);
394 struct llc_conn_state *curr_state =
395 &llc_conn_state_table[llc->state - 1];
396
397 /* search thru events for this state until
398 * list exhausted or until no more
399 */
400 for (next_trans = curr_state->transitions +
401 llc_find_offset(llc->state - 1, ev->type);
402 (*next_trans)->ev; next_trans++) {
403 if (!((*next_trans)->ev)(sk, skb)) {
404 /* got POSSIBLE event match; the event may require
405 * qualification based on the values of a number of
406 * state flags; if all qualifications are met (i.e.,
407 * if all qualifying functions return success, or 0,
408 * then this is THE event we're looking for
409 */
410 for (next_qualifier = (*next_trans)->ev_qualifiers;
411 next_qualifier && *next_qualifier &&
412 !(*next_qualifier)(sk, skb); next_qualifier++)
413 /* nothing */;
414 if (!next_qualifier || !*next_qualifier)
415 /* all qualifiers executed successfully; this is
416 * our transition; return it so we can perform
417 * the associated actions & change the state
418 */
419 return *next_trans;
420 }
421 }
422 return NULL;
423 }
424
425 /**
426 * llc_exec_conn_trans_actions - executes related actions
427 * @sk: connection
428 * @trans: transition that it's actions must be performed
429 * @skb: event
430 *
431 * Executes actions that is related to happened event. Returns 0 for
432 * success, 1 to indicate failure of at least one action.
433 */
llc_exec_conn_trans_actions(struct sock * sk,const struct llc_conn_state_trans * trans,struct sk_buff * skb)434 static int llc_exec_conn_trans_actions(struct sock *sk,
435 const struct llc_conn_state_trans *trans,
436 struct sk_buff *skb)
437 {
438 int rc = 0;
439 const llc_conn_action_t *next_action;
440
441 for (next_action = trans->ev_actions;
442 next_action && *next_action; next_action++) {
443 int rc2 = (*next_action)(sk, skb);
444
445 if (rc2 == 2) {
446 rc = rc2;
447 break;
448 } else if (rc2)
449 rc = 1;
450 }
451 return rc;
452 }
453
llc_estab_match(const struct llc_sap * sap,const struct llc_addr * daddr,const struct llc_addr * laddr,const struct sock * sk,const struct net * net)454 static inline bool llc_estab_match(const struct llc_sap *sap,
455 const struct llc_addr *daddr,
456 const struct llc_addr *laddr,
457 const struct sock *sk,
458 const struct net *net)
459 {
460 struct llc_sock *llc = llc_sk(sk);
461
462 return net_eq(sock_net(sk), net) &&
463 llc->laddr.lsap == laddr->lsap &&
464 llc->daddr.lsap == daddr->lsap &&
465 ether_addr_equal(llc->laddr.mac, laddr->mac) &&
466 ether_addr_equal(llc->daddr.mac, daddr->mac);
467 }
468
469 /**
470 * __llc_lookup_established - Finds connection for the remote/local sap/mac
471 * @sap: SAP
472 * @daddr: address of remote LLC (MAC + SAP)
473 * @laddr: address of local LLC (MAC + SAP)
474 * @net: netns to look up a socket in
475 *
476 * Search connection list of the SAP and finds connection using the remote
477 * mac, remote sap, local mac, and local sap. Returns pointer for
478 * connection found, %NULL otherwise.
479 * Caller has to make sure local_bh is disabled.
480 */
__llc_lookup_established(struct llc_sap * sap,struct llc_addr * daddr,struct llc_addr * laddr,const struct net * net)481 static struct sock *__llc_lookup_established(struct llc_sap *sap,
482 struct llc_addr *daddr,
483 struct llc_addr *laddr,
484 const struct net *net)
485 {
486 struct sock *rc;
487 struct hlist_nulls_node *node;
488 int slot = llc_sk_laddr_hashfn(sap, laddr);
489 struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
490
491 rcu_read_lock();
492 again:
493 sk_nulls_for_each_rcu(rc, node, laddr_hb) {
494 if (llc_estab_match(sap, daddr, laddr, rc, net)) {
495 /* Extra checks required by SLAB_TYPESAFE_BY_RCU */
496 if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
497 goto again;
498 if (unlikely(llc_sk(rc)->sap != sap ||
499 !llc_estab_match(sap, daddr, laddr, rc, net))) {
500 sock_put(rc);
501 continue;
502 }
503 goto found;
504 }
505 }
506 rc = NULL;
507 /*
508 * if the nulls value we got at the end of this lookup is
509 * not the expected one, we must restart lookup.
510 * We probably met an item that was moved to another chain.
511 */
512 if (unlikely(get_nulls_value(node) != slot))
513 goto again;
514 found:
515 rcu_read_unlock();
516 return rc;
517 }
518
llc_lookup_established(struct llc_sap * sap,struct llc_addr * daddr,struct llc_addr * laddr,const struct net * net)519 struct sock *llc_lookup_established(struct llc_sap *sap,
520 struct llc_addr *daddr,
521 struct llc_addr *laddr,
522 const struct net *net)
523 {
524 struct sock *sk;
525
526 local_bh_disable();
527 sk = __llc_lookup_established(sap, daddr, laddr, net);
528 local_bh_enable();
529 return sk;
530 }
531
llc_listener_match(const struct llc_sap * sap,const struct llc_addr * laddr,const struct sock * sk,const struct net * net)532 static inline bool llc_listener_match(const struct llc_sap *sap,
533 const struct llc_addr *laddr,
534 const struct sock *sk,
535 const struct net *net)
536 {
537 struct llc_sock *llc = llc_sk(sk);
538
539 return net_eq(sock_net(sk), net) &&
540 sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN &&
541 llc->laddr.lsap == laddr->lsap &&
542 ether_addr_equal(llc->laddr.mac, laddr->mac);
543 }
544
__llc_lookup_listener(struct llc_sap * sap,struct llc_addr * laddr,const struct net * net)545 static struct sock *__llc_lookup_listener(struct llc_sap *sap,
546 struct llc_addr *laddr,
547 const struct net *net)
548 {
549 struct sock *rc;
550 struct hlist_nulls_node *node;
551 int slot = llc_sk_laddr_hashfn(sap, laddr);
552 struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
553
554 rcu_read_lock();
555 again:
556 sk_nulls_for_each_rcu(rc, node, laddr_hb) {
557 if (llc_listener_match(sap, laddr, rc, net)) {
558 /* Extra checks required by SLAB_TYPESAFE_BY_RCU */
559 if (unlikely(!refcount_inc_not_zero(&rc->sk_refcnt)))
560 goto again;
561 if (unlikely(llc_sk(rc)->sap != sap ||
562 !llc_listener_match(sap, laddr, rc, net))) {
563 sock_put(rc);
564 continue;
565 }
566 goto found;
567 }
568 }
569 rc = NULL;
570 /*
571 * if the nulls value we got at the end of this lookup is
572 * not the expected one, we must restart lookup.
573 * We probably met an item that was moved to another chain.
574 */
575 if (unlikely(get_nulls_value(node) != slot))
576 goto again;
577 found:
578 rcu_read_unlock();
579 return rc;
580 }
581
582 /**
583 * llc_lookup_listener - Finds listener for local MAC + SAP
584 * @sap: SAP
585 * @laddr: address of local LLC (MAC + SAP)
586 * @net: netns to look up a socket in
587 *
588 * Search connection list of the SAP and finds connection listening on
589 * local mac, and local sap. Returns pointer for parent socket found,
590 * %NULL otherwise.
591 * Caller has to make sure local_bh is disabled.
592 */
llc_lookup_listener(struct llc_sap * sap,struct llc_addr * laddr,const struct net * net)593 static struct sock *llc_lookup_listener(struct llc_sap *sap,
594 struct llc_addr *laddr,
595 const struct net *net)
596 {
597 struct sock *rc = __llc_lookup_listener(sap, laddr, net);
598 static struct llc_addr null_addr;
599
600 if (!rc)
601 rc = __llc_lookup_listener(sap, &null_addr, net);
602
603 return rc;
604 }
605
__llc_lookup(struct llc_sap * sap,struct llc_addr * daddr,struct llc_addr * laddr,const struct net * net)606 static struct sock *__llc_lookup(struct llc_sap *sap,
607 struct llc_addr *daddr,
608 struct llc_addr *laddr,
609 const struct net *net)
610 {
611 struct sock *sk = __llc_lookup_established(sap, daddr, laddr, net);
612
613 return sk ? : llc_lookup_listener(sap, laddr, net);
614 }
615
616 /**
617 * llc_data_accept_state - designates if in this state data can be sent.
618 * @state: state of connection.
619 *
620 * Returns 0 if data can be sent, 1 otherwise.
621 */
llc_data_accept_state(u8 state)622 u8 llc_data_accept_state(u8 state)
623 {
624 return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY &&
625 state != LLC_CONN_STATE_REJ;
626 }
627
628 /**
629 * llc_find_next_offset - finds offset for next category of transitions
630 * @state: state table.
631 * @offset: start offset.
632 *
633 * Finds offset of next category of transitions in transition table.
634 * Returns the start index of next category.
635 */
llc_find_next_offset(struct llc_conn_state * state,u16 offset)636 static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset)
637 {
638 const struct llc_conn_state_trans **next_trans;
639 u16 cnt = 0;
640
641 for (next_trans = state->transitions + offset;
642 (*next_trans)->ev; next_trans++)
643 ++cnt;
644 return cnt;
645 }
646
647 /**
648 * llc_build_offset_table - builds offset table of connection
649 *
650 * Fills offset table of connection state transition table
651 * (llc_offset_table).
652 */
llc_build_offset_table(void)653 void __init llc_build_offset_table(void)
654 {
655 struct llc_conn_state *curr_state;
656 int state, ev_type, next_offset;
657
658 for (state = 0; state < NBR_CONN_STATES; state++) {
659 curr_state = &llc_conn_state_table[state];
660 next_offset = 0;
661 for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) {
662 llc_offset_table[state][ev_type] = next_offset;
663 next_offset += llc_find_next_offset(curr_state,
664 next_offset) + 1;
665 }
666 }
667 }
668
669 /**
670 * llc_find_offset - finds start offset of category of transitions
671 * @state: state of connection
672 * @ev_type: type of happened event
673 *
674 * Finds start offset of desired category of transitions. Returns the
675 * desired start offset.
676 */
llc_find_offset(int state,int ev_type)677 static int llc_find_offset(int state, int ev_type)
678 {
679 int rc = 0;
680 /* at this stage, llc_offset_table[..][2] is not important. it is for
681 * init_pf_cycle and I don't know what is it.
682 */
683 switch (ev_type) {
684 case LLC_CONN_EV_TYPE_PRIM:
685 rc = llc_offset_table[state][0]; break;
686 case LLC_CONN_EV_TYPE_PDU:
687 rc = llc_offset_table[state][4]; break;
688 case LLC_CONN_EV_TYPE_SIMPLE:
689 rc = llc_offset_table[state][1]; break;
690 case LLC_CONN_EV_TYPE_P_TMR:
691 case LLC_CONN_EV_TYPE_ACK_TMR:
692 case LLC_CONN_EV_TYPE_REJ_TMR:
693 case LLC_CONN_EV_TYPE_BUSY_TMR:
694 rc = llc_offset_table[state][3]; break;
695 }
696 return rc;
697 }
698
699 /**
700 * llc_sap_add_socket - adds a socket to a SAP
701 * @sap: SAP
702 * @sk: socket
703 *
704 * This function adds a socket to the hash tables of a SAP.
705 */
llc_sap_add_socket(struct llc_sap * sap,struct sock * sk)706 void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
707 {
708 struct llc_sock *llc = llc_sk(sk);
709 struct hlist_head *dev_hb = llc_sk_dev_hash(sap, llc->dev->ifindex);
710 struct hlist_nulls_head *laddr_hb = llc_sk_laddr_hash(sap, &llc->laddr);
711
712 llc_sap_hold(sap);
713 llc_sk(sk)->sap = sap;
714
715 spin_lock_bh(&sap->sk_lock);
716 sock_set_flag(sk, SOCK_RCU_FREE);
717 sap->sk_count++;
718 sk_nulls_add_node_rcu(sk, laddr_hb);
719 hlist_add_head(&llc->dev_hash_node, dev_hb);
720 spin_unlock_bh(&sap->sk_lock);
721 }
722
723 /**
724 * llc_sap_remove_socket - removes a socket from SAP
725 * @sap: SAP
726 * @sk: socket
727 *
728 * This function removes a connection from the hash tables of a SAP if
729 * the connection was in this list.
730 */
llc_sap_remove_socket(struct llc_sap * sap,struct sock * sk)731 void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
732 {
733 struct llc_sock *llc = llc_sk(sk);
734
735 spin_lock_bh(&sap->sk_lock);
736 sk_nulls_del_node_init_rcu(sk);
737 hlist_del(&llc->dev_hash_node);
738 sap->sk_count--;
739 spin_unlock_bh(&sap->sk_lock);
740 llc_sap_put(sap);
741 }
742
743 /**
744 * llc_conn_rcv - sends received pdus to the connection state machine
745 * @sk: current connection structure.
746 * @skb: received frame.
747 *
748 * Sends received pdus to the connection state machine.
749 */
llc_conn_rcv(struct sock * sk,struct sk_buff * skb)750 static int llc_conn_rcv(struct sock *sk, struct sk_buff *skb)
751 {
752 struct llc_conn_state_ev *ev = llc_conn_ev(skb);
753
754 ev->type = LLC_CONN_EV_TYPE_PDU;
755 ev->reason = 0;
756 return llc_conn_state_process(sk, skb);
757 }
758
llc_create_incoming_sock(struct sock * sk,struct net_device * dev,struct llc_addr * saddr,struct llc_addr * daddr)759 static struct sock *llc_create_incoming_sock(struct sock *sk,
760 struct net_device *dev,
761 struct llc_addr *saddr,
762 struct llc_addr *daddr)
763 {
764 struct sock *newsk = llc_sk_alloc(sock_net(sk), sk->sk_family, GFP_ATOMIC,
765 sk->sk_prot, 0);
766 struct llc_sock *newllc, *llc = llc_sk(sk);
767
768 if (!newsk)
769 goto out;
770 newllc = llc_sk(newsk);
771 memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
772 memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
773 newllc->dev = dev;
774 dev_hold(dev);
775 llc_sap_add_socket(llc->sap, newsk);
776 llc_sap_hold(llc->sap);
777 out:
778 return newsk;
779 }
780
llc_conn_handler(struct llc_sap * sap,struct sk_buff * skb)781 void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
782 {
783 struct llc_addr saddr, daddr;
784 struct sock *sk;
785
786 llc_pdu_decode_sa(skb, saddr.mac);
787 llc_pdu_decode_ssap(skb, &saddr.lsap);
788 llc_pdu_decode_da(skb, daddr.mac);
789 llc_pdu_decode_dsap(skb, &daddr.lsap);
790
791 sk = __llc_lookup(sap, &saddr, &daddr, dev_net(skb->dev));
792 if (!sk)
793 goto drop;
794
795 bh_lock_sock(sk);
796 /*
797 * This has to be done here and not at the upper layer ->accept
798 * method because of the way the PROCOM state machine works:
799 * it needs to set several state variables (see, for instance,
800 * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
801 * the originator of the new connection, and this state has to be
802 * in the newly created struct sock private area. -acme
803 */
804 if (unlikely(sk->sk_state == TCP_LISTEN)) {
805 struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
806 &saddr, &daddr);
807 if (!newsk)
808 goto drop_unlock;
809 skb_set_owner_r(skb, newsk);
810 } else {
811 /*
812 * Can't be skb_set_owner_r, this will be done at the
813 * llc_conn_state_process function, later on, when we will use
814 * skb_queue_rcv_skb to send it to upper layers, this is
815 * another trick required to cope with how the PROCOM state
816 * machine works. -acme
817 */
818 skb_orphan(skb);
819 sock_hold(sk);
820 skb->sk = sk;
821 skb->destructor = sock_efree;
822 }
823 if (!sock_owned_by_user(sk))
824 llc_conn_rcv(sk, skb);
825 else {
826 dprintk("%s: adding to backlog...\n", __func__);
827 llc_set_backlog_type(skb, LLC_PACKET);
828 if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)))
829 goto drop_unlock;
830 }
831 out:
832 bh_unlock_sock(sk);
833 sock_put(sk);
834 return;
835 drop:
836 kfree_skb(skb);
837 return;
838 drop_unlock:
839 kfree_skb(skb);
840 goto out;
841 }
842
843 #undef LLC_REFCNT_DEBUG
844 #ifdef LLC_REFCNT_DEBUG
845 static atomic_t llc_sock_nr;
846 #endif
847
848 /**
849 * llc_backlog_rcv - Processes rx frames and expired timers.
850 * @sk: LLC sock (p8022 connection)
851 * @skb: queued rx frame or event
852 *
853 * This function processes frames that has received and timers that has
854 * expired during sending an I pdu (refer to data_req_handler). frames
855 * queue by llc_rcv function (llc_mac.c) and timers queue by timer
856 * callback functions(llc_c_ac.c).
857 */
llc_backlog_rcv(struct sock * sk,struct sk_buff * skb)858 static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
859 {
860 int rc = 0;
861 struct llc_sock *llc = llc_sk(sk);
862
863 if (likely(llc_backlog_type(skb) == LLC_PACKET)) {
864 if (likely(llc->state > 1)) /* not closed */
865 rc = llc_conn_rcv(sk, skb);
866 else
867 goto out_kfree_skb;
868 } else if (llc_backlog_type(skb) == LLC_EVENT) {
869 /* timer expiration event */
870 if (likely(llc->state > 1)) /* not closed */
871 rc = llc_conn_state_process(sk, skb);
872 else
873 goto out_kfree_skb;
874 } else {
875 printk(KERN_ERR "%s: invalid skb in backlog\n", __func__);
876 goto out_kfree_skb;
877 }
878 out:
879 return rc;
880 out_kfree_skb:
881 kfree_skb(skb);
882 goto out;
883 }
884
885 /**
886 * llc_sk_init - Initializes a socket with default llc values.
887 * @sk: socket to initialize.
888 *
889 * Initializes a socket with default llc values.
890 */
llc_sk_init(struct sock * sk)891 static void llc_sk_init(struct sock *sk)
892 {
893 struct llc_sock *llc = llc_sk(sk);
894
895 llc->state = LLC_CONN_STATE_ADM;
896 llc->inc_cntr = llc->dec_cntr = 2;
897 llc->dec_step = llc->connect_step = 1;
898
899 timer_setup(&llc->ack_timer.timer, llc_conn_ack_tmr_cb, 0);
900 llc->ack_timer.expire = sysctl_llc2_ack_timeout;
901
902 timer_setup(&llc->pf_cycle_timer.timer, llc_conn_pf_cycle_tmr_cb, 0);
903 llc->pf_cycle_timer.expire = sysctl_llc2_p_timeout;
904
905 timer_setup(&llc->rej_sent_timer.timer, llc_conn_rej_tmr_cb, 0);
906 llc->rej_sent_timer.expire = sysctl_llc2_rej_timeout;
907
908 timer_setup(&llc->busy_state_timer.timer, llc_conn_busy_tmr_cb, 0);
909 llc->busy_state_timer.expire = sysctl_llc2_busy_timeout;
910
911 llc->n2 = 2; /* max retransmit */
912 llc->k = 2; /* tx win size, will adjust dynam */
913 llc->rw = 128; /* rx win size (opt and equal to
914 * tx_win of remote LLC) */
915 skb_queue_head_init(&llc->pdu_unack_q);
916 sk->sk_backlog_rcv = llc_backlog_rcv;
917 }
918
919 /**
920 * llc_sk_alloc - Allocates LLC sock
921 * @net: network namespace
922 * @family: upper layer protocol family
923 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
924 * @prot: struct proto associated with this new sock instance
925 * @kern: is this to be a kernel socket?
926 *
927 * Allocates a LLC sock and initializes it. Returns the new LLC sock
928 * or %NULL if there's no memory available for one
929 */
llc_sk_alloc(struct net * net,int family,gfp_t priority,struct proto * prot,int kern)930 struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot, int kern)
931 {
932 struct sock *sk = sk_alloc(net, family, priority, prot, kern);
933
934 if (!sk)
935 goto out;
936 llc_sk_init(sk);
937 sock_init_data(NULL, sk);
938 #ifdef LLC_REFCNT_DEBUG
939 atomic_inc(&llc_sock_nr);
940 printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk,
941 __func__, atomic_read(&llc_sock_nr));
942 #endif
943 out:
944 return sk;
945 }
946
llc_sk_stop_all_timers(struct sock * sk,bool sync)947 void llc_sk_stop_all_timers(struct sock *sk, bool sync)
948 {
949 struct llc_sock *llc = llc_sk(sk);
950
951 if (sync) {
952 del_timer_sync(&llc->pf_cycle_timer.timer);
953 del_timer_sync(&llc->ack_timer.timer);
954 del_timer_sync(&llc->rej_sent_timer.timer);
955 del_timer_sync(&llc->busy_state_timer.timer);
956 } else {
957 del_timer(&llc->pf_cycle_timer.timer);
958 del_timer(&llc->ack_timer.timer);
959 del_timer(&llc->rej_sent_timer.timer);
960 del_timer(&llc->busy_state_timer.timer);
961 }
962
963 llc->ack_must_be_send = 0;
964 llc->ack_pf = 0;
965 }
966
967 /**
968 * llc_sk_free - Frees a LLC socket
969 * @sk: - socket to free
970 *
971 * Frees a LLC socket
972 */
llc_sk_free(struct sock * sk)973 void llc_sk_free(struct sock *sk)
974 {
975 struct llc_sock *llc = llc_sk(sk);
976
977 llc->state = LLC_CONN_OUT_OF_SVC;
978 /* Stop all (possibly) running timers */
979 llc_sk_stop_all_timers(sk, true);
980 #ifdef DEBUG_LLC_CONN_ALLOC
981 printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __func__,
982 skb_queue_len(&llc->pdu_unack_q),
983 skb_queue_len(&sk->sk_write_queue));
984 #endif
985 skb_queue_purge(&sk->sk_receive_queue);
986 skb_queue_purge(&sk->sk_write_queue);
987 skb_queue_purge(&llc->pdu_unack_q);
988 #ifdef LLC_REFCNT_DEBUG
989 if (refcount_read(&sk->sk_refcnt) != 1) {
990 printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
991 sk, __func__, refcount_read(&sk->sk_refcnt));
992 printk(KERN_DEBUG "%d LLC sockets are still alive\n",
993 atomic_read(&llc_sock_nr));
994 } else {
995 atomic_dec(&llc_sock_nr);
996 printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk,
997 __func__, atomic_read(&llc_sock_nr));
998 }
999 #endif
1000 sock_put(sk);
1001 }
1002
1003 /**
1004 * llc_sk_reset - resets a connection
1005 * @sk: LLC socket to reset
1006 *
1007 * Resets a connection to the out of service state. Stops its timers
1008 * and frees any frames in the queues of the connection.
1009 */
llc_sk_reset(struct sock * sk)1010 void llc_sk_reset(struct sock *sk)
1011 {
1012 struct llc_sock *llc = llc_sk(sk);
1013
1014 llc_conn_ac_stop_all_timers(sk, NULL);
1015 skb_queue_purge(&sk->sk_write_queue);
1016 skb_queue_purge(&llc->pdu_unack_q);
1017 llc->remote_busy_flag = 0;
1018 llc->cause_flag = 0;
1019 llc->retry_count = 0;
1020 llc_conn_set_p_flag(sk, 0);
1021 llc->f_flag = 0;
1022 llc->s_flag = 0;
1023 llc->ack_pf = 0;
1024 llc->first_pdu_Ns = 0;
1025 llc->ack_must_be_send = 0;
1026 llc->dec_step = 1;
1027 llc->inc_cntr = 2;
1028 llc->dec_cntr = 2;
1029 llc->X = 0;
1030 llc->failed_data_req = 0 ;
1031 llc->last_nr = 0;
1032 }
1033