blob: 3e821daf9dd4a2fbf00550591e92b153efd4a73a [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090016#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <net/llc_sap.h>
18#include <net/llc_conn.h>
19#include <net/sock.h>
Arnaldo Carvalho de Meloc752f072005-08-09 20:08:28 -070020#include <net/tcp_states.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <net/llc_c_ev.h>
22#include <net/llc_c_ac.h>
23#include <net/llc_c_st.h>
24#include <net/llc_pdu.h>
25
26#if 0
27#define dprintk(args...) printk(KERN_DEBUG args)
28#else
29#define dprintk(args...)
30#endif
31
32static int llc_find_offset(int state, int ev_type);
33static void llc_conn_send_pdus(struct sock *sk);
34static int llc_conn_service(struct sock *sk, struct sk_buff *skb);
35static int llc_exec_conn_trans_actions(struct sock *sk,
36 struct llc_conn_state_trans *trans,
37 struct sk_buff *ev);
38static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
39 struct sk_buff *skb);
40
41/* Offset table on connection states transition diagram */
42static int llc_offset_table[NBR_CONN_STATES][NBR_CONN_EV];
43
Arnaldo Carvalho de Melo590232a2005-09-22 04:30:44 -030044int sysctl_llc2_ack_timeout = LLC2_ACK_TIME * HZ;
45int sysctl_llc2_p_timeout = LLC2_P_TIME * HZ;
46int sysctl_llc2_rej_timeout = LLC2_REJ_TIME * HZ;
47int sysctl_llc2_busy_timeout = LLC2_BUSY_TIME * HZ;
48
Linus Torvalds1da177e2005-04-16 15:20:36 -070049/**
50 * llc_conn_state_process - sends event to connection state machine
51 * @sk: connection
52 * @skb: occurred event
53 *
54 * Sends an event to connection state machine. After processing event
55 * (executing it's actions and changing state), upper layer will be
56 * indicated or confirmed, if needed. Returns 0 for success, 1 for
57 * failure. The socket lock has to be held before calling this function.
58 */
59int llc_conn_state_process(struct sock *sk, struct sk_buff *skb)
60{
61 int rc;
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -030062 struct llc_sock *llc = llc_sk(skb->sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 struct llc_conn_state_ev *ev = llc_conn_ev(skb);
64
65 /*
66 * We have to hold the skb, because llc_conn_service will kfree it in
67 * the sending path and we need to look at the skb->cb, where we encode
68 * llc_conn_state_ev.
69 */
70 skb_get(skb);
71 ev->ind_prim = ev->cfm_prim = 0;
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -030072 /*
73 * Send event to state machine
74 */
75 rc = llc_conn_service(skb->sk, skb);
Arnaldo Carvalho de Meloaf426d32005-09-22 03:59:22 -030076 if (unlikely(rc != 0)) {
Harvey Harrison0dc47872008-03-05 20:47:47 -080077 printk(KERN_ERR "%s: llc_conn_service failed\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 goto out_kfree_skb;
79 }
80
Arnaldo Carvalho de Meloaf426d32005-09-22 03:59:22 -030081 if (unlikely(!ev->ind_prim && !ev->cfm_prim)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 /* indicate or confirm not required */
David S. Miller8728b832005-08-09 19:25:21 -070083 if (!skb->next)
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 goto out_kfree_skb;
85 goto out_skb_put;
86 }
87
Arnaldo Carvalho de Meloaf426d32005-09-22 03:59:22 -030088 if (unlikely(ev->ind_prim && ev->cfm_prim)) /* Paranoia */
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 skb_get(skb);
90
91 switch (ev->ind_prim) {
92 case LLC_DATA_PRIM:
Arnaldo Carvalho de Melo04e42232005-09-22 04:40:59 -030093 llc_save_primitive(sk, skb, LLC_DATA_PRIM);
94 if (unlikely(sock_queue_rcv_skb(sk, skb))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 /*
96 * shouldn't happen
97 */
98 printk(KERN_ERR "%s: sock_queue_rcv_skb failed!\n",
Harvey Harrison0dc47872008-03-05 20:47:47 -080099 __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 kfree_skb(skb);
101 }
102 break;
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300103 case LLC_CONN_PRIM:
Arnaldo Carvalho de Melo04e42232005-09-22 04:40:59 -0300104 /*
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300105 * Can't be sock_queue_rcv_skb, because we have to leave the
106 * skb->sk pointing to the newly created struct sock in
107 * llc_conn_handler. -acme
Arnaldo Carvalho de Melo04e42232005-09-22 04:40:59 -0300108 */
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300109 skb_queue_tail(&sk->sk_receive_queue, skb);
110 sk->sk_state_change(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 break;
112 case LLC_DISC_PRIM:
113 sock_hold(sk);
114 if (sk->sk_type == SOCK_STREAM &&
115 sk->sk_state == TCP_ESTABLISHED) {
116 sk->sk_shutdown = SHUTDOWN_MASK;
117 sk->sk_socket->state = SS_UNCONNECTED;
118 sk->sk_state = TCP_CLOSE;
119 if (!sock_flag(sk, SOCK_DEAD)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 sock_set_flag(sk, SOCK_DEAD);
Arnaldo Carvalho de Melo8420e1b2005-09-22 08:29:08 -0300121 sk->sk_state_change(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 }
123 }
124 kfree_skb(skb);
125 sock_put(sk);
126 break;
127 case LLC_RESET_PRIM:
128 /*
129 * FIXME:
130 * RESET is not being notified to upper layers for now
131 */
Harvey Harrison0dc47872008-03-05 20:47:47 -0800132 printk(KERN_INFO "%s: received a reset ind!\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 kfree_skb(skb);
134 break;
135 default:
136 if (ev->ind_prim) {
137 printk(KERN_INFO "%s: received unknown %d prim!\n",
Harvey Harrison0dc47872008-03-05 20:47:47 -0800138 __func__, ev->ind_prim);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 kfree_skb(skb);
140 }
141 /* No indication */
142 break;
143 }
144
145 switch (ev->cfm_prim) {
146 case LLC_DATA_PRIM:
147 if (!llc_data_accept_state(llc->state))
148 sk->sk_write_space(sk);
149 else
150 rc = llc->failed_data_req = 1;
151 break;
152 case LLC_CONN_PRIM:
153 if (sk->sk_type == SOCK_STREAM &&
154 sk->sk_state == TCP_SYN_SENT) {
155 if (ev->status) {
156 sk->sk_socket->state = SS_UNCONNECTED;
157 sk->sk_state = TCP_CLOSE;
158 } else {
159 sk->sk_socket->state = SS_CONNECTED;
160 sk->sk_state = TCP_ESTABLISHED;
161 }
162 sk->sk_state_change(sk);
163 }
164 break;
165 case LLC_DISC_PRIM:
166 sock_hold(sk);
167 if (sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_CLOSING) {
168 sk->sk_socket->state = SS_UNCONNECTED;
169 sk->sk_state = TCP_CLOSE;
170 sk->sk_state_change(sk);
171 }
172 sock_put(sk);
173 break;
174 case LLC_RESET_PRIM:
175 /*
176 * FIXME:
177 * RESET is not being notified to upper layers for now
178 */
Harvey Harrison0dc47872008-03-05 20:47:47 -0800179 printk(KERN_INFO "%s: received a reset conf!\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 break;
181 default:
182 if (ev->cfm_prim) {
183 printk(KERN_INFO "%s: received unknown %d prim!\n",
Harvey Harrison0dc47872008-03-05 20:47:47 -0800184 __func__, ev->cfm_prim);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 break;
186 }
187 goto out_skb_put; /* No confirmation */
188 }
189out_kfree_skb:
190 kfree_skb(skb);
191out_skb_put:
192 kfree_skb(skb);
193 return rc;
194}
195
196void llc_conn_send_pdu(struct sock *sk, struct sk_buff *skb)
197{
198 /* queue PDU to send to MAC layer */
199 skb_queue_tail(&sk->sk_write_queue, skb);
200 llc_conn_send_pdus(sk);
201}
202
203/**
204 * llc_conn_rtn_pdu - sends received data pdu to upper layer
205 * @sk: Active connection
206 * @skb: Received data frame
207 *
208 * Sends received data pdu to upper layer (by using indicate function).
209 * Prepares service parameters (prim and prim_data). calling indication
210 * function will be done in llc_conn_state_process.
211 */
212void llc_conn_rtn_pdu(struct sock *sk, struct sk_buff *skb)
213{
214 struct llc_conn_state_ev *ev = llc_conn_ev(skb);
215
216 ev->ind_prim = LLC_DATA_PRIM;
217}
218
219/**
220 * llc_conn_resend_i_pdu_as_cmd - resend all all unacknowledged I PDUs
221 * @sk: active connection
222 * @nr: NR
223 * @first_p_bit: p_bit value of first pdu
224 *
225 * Resend all unacknowledged I PDUs, starting with the NR; send first as
226 * command PDU with P bit equal first_p_bit; if more than one send
227 * subsequent as command PDUs with P bit equal zero (0).
228 */
229void llc_conn_resend_i_pdu_as_cmd(struct sock *sk, u8 nr, u8 first_p_bit)
230{
231 struct sk_buff *skb;
232 struct llc_pdu_sn *pdu;
233 u16 nbr_unack_pdus;
234 struct llc_sock *llc;
235 u8 howmany_resend = 0;
236
237 llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
238 if (!nbr_unack_pdus)
239 goto out;
240 /*
241 * Process unack PDUs only if unack queue is not empty; remove
242 * appropriate PDUs, fix them up, and put them on mac_pdu_q.
243 */
244 llc = llc_sk(sk);
245
246 while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
247 pdu = llc_pdu_sn_hdr(skb);
248 llc_pdu_set_cmd_rsp(skb, LLC_PDU_CMD);
249 llc_pdu_set_pf_bit(skb, first_p_bit);
250 skb_queue_tail(&sk->sk_write_queue, skb);
251 first_p_bit = 0;
252 llc->vS = LLC_I_GET_NS(pdu);
253 howmany_resend++;
254 }
255 if (howmany_resend > 0)
256 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
257 /* any PDUs to re-send are queued up; start sending to MAC */
258 llc_conn_send_pdus(sk);
259out:;
260}
261
262/**
263 * llc_conn_resend_i_pdu_as_rsp - Resend all unacknowledged I PDUs
264 * @sk: active connection.
265 * @nr: NR
266 * @first_f_bit: f_bit value of first pdu.
267 *
268 * Resend all unacknowledged I PDUs, starting with the NR; send first as
269 * response PDU with F bit equal first_f_bit; if more than one send
270 * subsequent as response PDUs with F bit equal zero (0).
271 */
272void llc_conn_resend_i_pdu_as_rsp(struct sock *sk, u8 nr, u8 first_f_bit)
273{
274 struct sk_buff *skb;
275 u16 nbr_unack_pdus;
276 struct llc_sock *llc = llc_sk(sk);
277 u8 howmany_resend = 0;
278
279 llc_conn_remove_acked_pdus(sk, nr, &nbr_unack_pdus);
280 if (!nbr_unack_pdus)
281 goto out;
282 /*
283 * Process unack PDUs only if unack queue is not empty; remove
284 * appropriate PDUs, fix them up, and put them on mac_pdu_q
285 */
286 while ((skb = skb_dequeue(&llc->pdu_unack_q)) != NULL) {
287 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
288
289 llc_pdu_set_cmd_rsp(skb, LLC_PDU_RSP);
290 llc_pdu_set_pf_bit(skb, first_f_bit);
291 skb_queue_tail(&sk->sk_write_queue, skb);
292 first_f_bit = 0;
293 llc->vS = LLC_I_GET_NS(pdu);
294 howmany_resend++;
295 }
296 if (howmany_resend > 0)
297 llc->vS = (llc->vS + 1) % LLC_2_SEQ_NBR_MODULO;
298 /* any PDUs to re-send are queued up; start sending to MAC */
299 llc_conn_send_pdus(sk);
300out:;
301}
302
303/**
304 * llc_conn_remove_acked_pdus - Removes acknowledged pdus from tx queue
305 * @sk: active connection
306 * nr: NR
307 * how_many_unacked: size of pdu_unack_q after removing acked pdus
308 *
309 * Removes acknowledged pdus from transmit queue (pdu_unack_q). Returns
310 * the number of pdus that removed from queue.
311 */
312int llc_conn_remove_acked_pdus(struct sock *sk, u8 nr, u16 *how_many_unacked)
313{
314 int pdu_pos, i;
315 struct sk_buff *skb;
316 struct llc_pdu_sn *pdu;
317 int nbr_acked = 0;
318 struct llc_sock *llc = llc_sk(sk);
319 int q_len = skb_queue_len(&llc->pdu_unack_q);
320
321 if (!q_len)
322 goto out;
323 skb = skb_peek(&llc->pdu_unack_q);
324 pdu = llc_pdu_sn_hdr(skb);
325
326 /* finding position of last acked pdu in queue */
327 pdu_pos = ((int)LLC_2_SEQ_NBR_MODULO + (int)nr -
328 (int)LLC_I_GET_NS(pdu)) % LLC_2_SEQ_NBR_MODULO;
329
330 for (i = 0; i < pdu_pos && i < q_len; i++) {
331 skb = skb_dequeue(&llc->pdu_unack_q);
Wei Yongjunc3431ea2009-02-25 00:42:22 +0000332 kfree_skb(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 nbr_acked++;
334 }
335out:
336 *how_many_unacked = skb_queue_len(&llc->pdu_unack_q);
337 return nbr_acked;
338}
339
340/**
341 * llc_conn_send_pdus - Sends queued PDUs
342 * @sk: active connection
343 *
344 * Sends queued pdus to MAC layer for transmission.
345 */
346static void llc_conn_send_pdus(struct sock *sk)
347{
348 struct sk_buff *skb;
349
350 while ((skb = skb_dequeue(&sk->sk_write_queue)) != NULL) {
351 struct llc_pdu_sn *pdu = llc_pdu_sn_hdr(skb);
352
353 if (LLC_PDU_TYPE_IS_I(pdu) &&
354 !(skb->dev->flags & IFF_LOOPBACK)) {
355 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
356
357 skb_queue_tail(&llc_sk(sk)->pdu_unack_q, skb);
358 if (!skb2)
359 break;
360 skb = skb2;
361 }
362 dev_queue_xmit(skb);
363 }
364}
365
366/**
367 * llc_conn_service - finds transition and changes state of connection
368 * @sk: connection
369 * @skb: happened event
370 *
371 * This function finds transition that matches with happened event, then
372 * executes related actions and finally changes state of connection.
373 * Returns 0 for success, 1 for failure.
374 */
375static int llc_conn_service(struct sock *sk, struct sk_buff *skb)
376{
377 int rc = 1;
378 struct llc_sock *llc = llc_sk(sk);
379 struct llc_conn_state_trans *trans;
380
381 if (llc->state > NBR_CONN_STATES)
382 goto out;
383 rc = 0;
384 trans = llc_qualify_conn_ev(sk, skb);
385 if (trans) {
386 rc = llc_exec_conn_trans_actions(sk, trans, skb);
387 if (!rc && trans->next_state != NO_STATE_CHANGE) {
388 llc->state = trans->next_state;
389 if (!llc_data_accept_state(llc->state))
390 sk->sk_state_change(sk);
391 }
392 }
393out:
394 return rc;
395}
396
397/**
398 * llc_qualify_conn_ev - finds transition for event
399 * @sk: connection
400 * @skb: happened event
401 *
402 * This function finds transition that matches with happened event.
403 * Returns pointer to found transition on success, %NULL otherwise.
404 */
405static struct llc_conn_state_trans *llc_qualify_conn_ev(struct sock *sk,
406 struct sk_buff *skb)
407{
408 struct llc_conn_state_trans **next_trans;
Joe Perches9b373062014-12-10 09:43:57 -0800409 const llc_conn_ev_qfyr_t *next_qualifier;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 struct llc_conn_state_ev *ev = llc_conn_ev(skb);
411 struct llc_sock *llc = llc_sk(sk);
412 struct llc_conn_state *curr_state =
413 &llc_conn_state_table[llc->state - 1];
414
415 /* search thru events for this state until
416 * list exhausted or until no more
417 */
418 for (next_trans = curr_state->transitions +
419 llc_find_offset(llc->state - 1, ev->type);
420 (*next_trans)->ev; next_trans++) {
421 if (!((*next_trans)->ev)(sk, skb)) {
422 /* got POSSIBLE event match; the event may require
423 * qualification based on the values of a number of
424 * state flags; if all qualifications are met (i.e.,
425 * if all qualifying functions return success, or 0,
426 * then this is THE event we're looking for
427 */
428 for (next_qualifier = (*next_trans)->ev_qualifiers;
429 next_qualifier && *next_qualifier &&
430 !(*next_qualifier)(sk, skb); next_qualifier++)
431 /* nothing */;
432 if (!next_qualifier || !*next_qualifier)
433 /* all qualifiers executed successfully; this is
434 * our transition; return it so we can perform
435 * the associated actions & change the state
436 */
437 return *next_trans;
438 }
439 }
440 return NULL;
441}
442
443/**
444 * llc_exec_conn_trans_actions - executes related actions
445 * @sk: connection
446 * @trans: transition that it's actions must be performed
447 * @skb: event
448 *
449 * Executes actions that is related to happened event. Returns 0 for
450 * success, 1 to indicate failure of at least one action.
451 */
452static int llc_exec_conn_trans_actions(struct sock *sk,
453 struct llc_conn_state_trans *trans,
454 struct sk_buff *skb)
455{
456 int rc = 0;
Joe Perches14b7d952014-12-10 08:18:50 -0800457 const llc_conn_action_t *next_action;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458
459 for (next_action = trans->ev_actions;
460 next_action && *next_action; next_action++) {
461 int rc2 = (*next_action)(sk, skb);
462
463 if (rc2 == 2) {
464 rc = rc2;
465 break;
466 } else if (rc2)
467 rc = 1;
468 }
469 return rc;
470}
471
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000472static inline bool llc_estab_match(const struct llc_sap *sap,
473 const struct llc_addr *daddr,
474 const struct llc_addr *laddr,
475 const struct sock *sk)
476{
477 struct llc_sock *llc = llc_sk(sk);
478
479 return llc->laddr.lsap == laddr->lsap &&
480 llc->daddr.lsap == daddr->lsap &&
Joe Perches951fd872013-09-01 13:11:55 -0700481 ether_addr_equal(llc->laddr.mac, laddr->mac) &&
482 ether_addr_equal(llc->daddr.mac, daddr->mac);
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000483}
484
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485/**
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300486 * __llc_lookup_established - Finds connection for the remote/local sap/mac
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 * @sap: SAP
488 * @daddr: address of remote LLC (MAC + SAP)
489 * @laddr: address of local LLC (MAC + SAP)
490 *
491 * Search connection list of the SAP and finds connection using the remote
492 * mac, remote sap, local mac, and local sap. Returns pointer for
493 * connection found, %NULL otherwise.
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300494 * Caller has to make sure local_bh is disabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 */
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300496static struct sock *__llc_lookup_established(struct llc_sap *sap,
497 struct llc_addr *daddr,
498 struct llc_addr *laddr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499{
500 struct sock *rc;
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000501 struct hlist_nulls_node *node;
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000502 int slot = llc_sk_laddr_hashfn(sap, laddr);
503 struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000505 rcu_read_lock();
506again:
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000507 sk_nulls_for_each_rcu(rc, node, laddr_hb) {
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000508 if (llc_estab_match(sap, daddr, laddr, rc)) {
509 /* Extra checks required by SLAB_DESTROY_BY_RCU */
510 if (unlikely(!atomic_inc_not_zero(&rc->sk_refcnt)))
511 goto again;
512 if (unlikely(llc_sk(rc)->sap != sap ||
513 !llc_estab_match(sap, daddr, laddr, rc))) {
514 sock_put(rc);
515 continue;
516 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 goto found;
518 }
519 }
520 rc = NULL;
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000521 /*
522 * if the nulls value we got at the end of this lookup is
523 * not the expected one, we must restart lookup.
524 * We probably met an item that was moved to another chain.
525 */
526 if (unlikely(get_nulls_value(node) != slot))
527 goto again;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528found:
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000529 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 return rc;
531}
532
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300533struct sock *llc_lookup_established(struct llc_sap *sap,
534 struct llc_addr *daddr,
535 struct llc_addr *laddr)
536{
537 struct sock *sk;
538
539 local_bh_disable();
540 sk = __llc_lookup_established(sap, daddr, laddr);
541 local_bh_enable();
542 return sk;
543}
544
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000545static inline bool llc_listener_match(const struct llc_sap *sap,
546 const struct llc_addr *laddr,
547 const struct sock *sk)
548{
549 struct llc_sock *llc = llc_sk(sk);
550
551 return sk->sk_type == SOCK_STREAM && sk->sk_state == TCP_LISTEN &&
552 llc->laddr.lsap == laddr->lsap &&
Joe Perches951fd872013-09-01 13:11:55 -0700553 ether_addr_equal(llc->laddr.mac, laddr->mac);
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000554}
555
556static struct sock *__llc_lookup_listener(struct llc_sap *sap,
557 struct llc_addr *laddr)
558{
559 struct sock *rc;
560 struct hlist_nulls_node *node;
561 int slot = llc_sk_laddr_hashfn(sap, laddr);
562 struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
563
564 rcu_read_lock();
565again:
566 sk_nulls_for_each_rcu(rc, node, laddr_hb) {
567 if (llc_listener_match(sap, laddr, rc)) {
568 /* Extra checks required by SLAB_DESTROY_BY_RCU */
569 if (unlikely(!atomic_inc_not_zero(&rc->sk_refcnt)))
570 goto again;
571 if (unlikely(llc_sk(rc)->sap != sap ||
572 !llc_listener_match(sap, laddr, rc))) {
573 sock_put(rc);
574 continue;
575 }
576 goto found;
577 }
578 }
579 rc = NULL;
580 /*
581 * if the nulls value we got at the end of this lookup is
582 * not the expected one, we must restart lookup.
583 * We probably met an item that was moved to another chain.
584 */
585 if (unlikely(get_nulls_value(node) != slot))
586 goto again;
587found:
588 rcu_read_unlock();
589 return rc;
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000590}
591
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592/**
593 * llc_lookup_listener - Finds listener for local MAC + SAP
594 * @sap: SAP
595 * @laddr: address of local LLC (MAC + SAP)
596 *
597 * Search connection list of the SAP and finds connection listening on
598 * local mac, and local sap. Returns pointer for parent socket found,
599 * %NULL otherwise.
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300600 * Caller has to make sure local_bh is disabled.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 */
602static struct sock *llc_lookup_listener(struct llc_sap *sap,
603 struct llc_addr *laddr)
604{
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000605 static struct llc_addr null_addr;
606 struct sock *rc = __llc_lookup_listener(sap, laddr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000608 if (!rc)
609 rc = __llc_lookup_listener(sap, &null_addr);
610
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 return rc;
612}
613
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300614static struct sock *__llc_lookup(struct llc_sap *sap,
615 struct llc_addr *daddr,
616 struct llc_addr *laddr)
617{
618 struct sock *sk = __llc_lookup_established(sap, daddr, laddr);
619
620 return sk ? : llc_lookup_listener(sap, laddr);
621}
622
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623/**
624 * llc_data_accept_state - designates if in this state data can be sent.
625 * @state: state of connection.
626 *
627 * Returns 0 if data can be sent, 1 otherwise.
628 */
629u8 llc_data_accept_state(u8 state)
630{
631 return state != LLC_CONN_STATE_NORMAL && state != LLC_CONN_STATE_BUSY &&
632 state != LLC_CONN_STATE_REJ;
633}
634
635/**
Arnaldo Carvalho de Melo0eb80172005-09-22 03:57:55 -0300636 * llc_find_next_offset - finds offset for next category of transitions
Linus Torvalds1da177e2005-04-16 15:20:36 -0700637 * @state: state table.
638 * @offset: start offset.
639 *
640 * Finds offset of next category of transitions in transition table.
641 * Returns the start index of next category.
642 */
Arnaldo Carvalho de Melo0eb80172005-09-22 03:57:55 -0300643static u16 __init llc_find_next_offset(struct llc_conn_state *state, u16 offset)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644{
645 u16 cnt = 0;
646 struct llc_conn_state_trans **next_trans;
647
648 for (next_trans = state->transitions + offset;
649 (*next_trans)->ev; next_trans++)
650 ++cnt;
651 return cnt;
652}
653
654/**
655 * llc_build_offset_table - builds offset table of connection
656 *
657 * Fills offset table of connection state transition table
658 * (llc_offset_table).
659 */
660void __init llc_build_offset_table(void)
661{
662 struct llc_conn_state *curr_state;
663 int state, ev_type, next_offset;
664
665 for (state = 0; state < NBR_CONN_STATES; state++) {
666 curr_state = &llc_conn_state_table[state];
667 next_offset = 0;
668 for (ev_type = 0; ev_type < NBR_CONN_EV; ev_type++) {
669 llc_offset_table[state][ev_type] = next_offset;
Arnaldo Carvalho de Melo0eb80172005-09-22 03:57:55 -0300670 next_offset += llc_find_next_offset(curr_state,
671 next_offset) + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 }
673 }
674}
675
676/**
677 * llc_find_offset - finds start offset of category of transitions
678 * @state: state of connection
679 * @ev_type: type of happened event
680 *
681 * Finds start offset of desired category of transitions. Returns the
682 * desired start offset.
683 */
684static int llc_find_offset(int state, int ev_type)
685{
686 int rc = 0;
687 /* at this stage, llc_offset_table[..][2] is not important. it is for
688 * init_pf_cycle and I don't know what is it.
689 */
690 switch (ev_type) {
691 case LLC_CONN_EV_TYPE_PRIM:
692 rc = llc_offset_table[state][0]; break;
693 case LLC_CONN_EV_TYPE_PDU:
694 rc = llc_offset_table[state][4]; break;
695 case LLC_CONN_EV_TYPE_SIMPLE:
696 rc = llc_offset_table[state][1]; break;
697 case LLC_CONN_EV_TYPE_P_TMR:
698 case LLC_CONN_EV_TYPE_ACK_TMR:
699 case LLC_CONN_EV_TYPE_REJ_TMR:
700 case LLC_CONN_EV_TYPE_BUSY_TMR:
701 rc = llc_offset_table[state][3]; break;
702 }
703 return rc;
704}
705
706/**
707 * llc_sap_add_socket - adds a socket to a SAP
708 * @sap: SAP
709 * @sk: socket
710 *
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000711 * This function adds a socket to the hash tables of a SAP.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 */
713void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
714{
Octavian Purdila6d2e3ea2009-12-26 11:51:04 +0000715 struct llc_sock *llc = llc_sk(sk);
716 struct hlist_head *dev_hb = llc_sk_dev_hash(sap, llc->dev->ifindex);
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000717 struct hlist_nulls_head *laddr_hb = llc_sk_laddr_hash(sap, &llc->laddr);
Octavian Purdila6d2e3ea2009-12-26 11:51:04 +0000718
Arnaldo Carvalho de Melo6e2144b2005-09-22 04:43:05 -0300719 llc_sap_hold(sap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 llc_sk(sk)->sap = sap;
Octavian Purdila6d2e3ea2009-12-26 11:51:04 +0000721
722 spin_lock_bh(&sap->sk_lock);
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000723 sap->sk_count++;
724 sk_nulls_add_node_rcu(sk, laddr_hb);
Octavian Purdila6d2e3ea2009-12-26 11:51:04 +0000725 hlist_add_head(&llc->dev_hash_node, dev_hb);
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000726 spin_unlock_bh(&sap->sk_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727}
728
729/**
730 * llc_sap_remove_socket - removes a socket from SAP
731 * @sap: SAP
732 * @sk: socket
733 *
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000734 * This function removes a connection from the hash tables of a SAP if
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 * the connection was in this list.
736 */
737void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
738{
Octavian Purdila6d2e3ea2009-12-26 11:51:04 +0000739 struct llc_sock *llc = llc_sk(sk);
740
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000741 spin_lock_bh(&sap->sk_lock);
742 sk_nulls_del_node_init_rcu(sk);
Octavian Purdila6d2e3ea2009-12-26 11:51:04 +0000743 hlist_del(&llc->dev_hash_node);
Octavian Purdila52d58ae2009-12-26 11:51:05 +0000744 sap->sk_count--;
Octavian Purdilab76f5a82009-12-26 11:51:02 +0000745 spin_unlock_bh(&sap->sk_lock);
Arnaldo Carvalho de Melo6e2144b2005-09-22 04:43:05 -0300746 llc_sap_put(sap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747}
748
749/**
750 * llc_conn_rcv - sends received pdus to the connection state machine
751 * @sk: current connection structure.
752 * @skb: received frame.
753 *
754 * Sends received pdus to the connection state machine.
755 */
Weilong Chen3cdba602013-12-20 11:14:59 +0800756static int llc_conn_rcv(struct sock *sk, struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757{
758 struct llc_conn_state_ev *ev = llc_conn_ev(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 ev->type = LLC_CONN_EV_TYPE_PDU;
761 ev->reason = 0;
762 return llc_conn_state_process(sk, skb);
763}
764
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300765static struct sock *llc_create_incoming_sock(struct sock *sk,
766 struct net_device *dev,
767 struct llc_addr *saddr,
768 struct llc_addr *daddr)
769{
YOSHIFUJI Hideaki3b1e0a62008-03-26 02:26:21 +0900770 struct sock *newsk = llc_sk_alloc(sock_net(sk), sk->sk_family, GFP_ATOMIC,
Eric W. Biederman11aa9c22015-05-08 21:09:13 -0500771 sk->sk_prot, 0);
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300772 struct llc_sock *newllc, *llc = llc_sk(sk);
773
774 if (!newsk)
775 goto out;
776 newllc = llc_sk(newsk);
777 memcpy(&newllc->laddr, daddr, sizeof(newllc->laddr));
778 memcpy(&newllc->daddr, saddr, sizeof(newllc->daddr));
779 newllc->dev = dev;
780 dev_hold(dev);
781 llc_sap_add_socket(llc->sap, newsk);
782 llc_sap_hold(llc->sap);
783out:
784 return newsk;
785}
786
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
788{
789 struct llc_addr saddr, daddr;
790 struct sock *sk;
791
792 llc_pdu_decode_sa(skb, saddr.mac);
793 llc_pdu_decode_ssap(skb, &saddr.lsap);
794 llc_pdu_decode_da(skb, daddr.mac);
795 llc_pdu_decode_dsap(skb, &daddr.lsap);
796
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300797 sk = __llc_lookup(sap, &saddr, &daddr);
798 if (!sk)
799 goto drop;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 bh_lock_sock(sk);
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300802 /*
803 * This has to be done here and not at the upper layer ->accept
804 * method because of the way the PROCOM state machine works:
805 * it needs to set several state variables (see, for instance,
806 * llc_adm_actions_2 in net/llc/llc_c_st.c) and send a packet to
807 * the originator of the new connection, and this state has to be
808 * in the newly created struct sock private area. -acme
809 */
810 if (unlikely(sk->sk_state == TCP_LISTEN)) {
811 struct sock *newsk = llc_create_incoming_sock(sk, skb->dev,
812 &saddr, &daddr);
813 if (!newsk)
814 goto drop_unlock;
815 skb_set_owner_r(skb, newsk);
816 } else {
817 /*
818 * Can't be skb_set_owner_r, this will be done at the
819 * llc_conn_state_process function, later on, when we will use
820 * skb_queue_rcv_skb to send it to upper layers, this is
821 * another trick required to cope with how the PROCOM state
822 * machine works. -acme
823 */
824 skb->sk = sk;
825 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 if (!sock_owned_by_user(sk))
827 llc_conn_rcv(sk, skb);
828 else {
Harvey Harrison0dc47872008-03-05 20:47:47 -0800829 dprintk("%s: adding to backlog...\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 llc_set_backlog_type(skb, LLC_PACKET);
Eric Dumazetf545a382012-04-22 23:34:26 +0000831 if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
Zhu Yi79545b62010-03-04 18:01:43 +0000832 goto drop_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 }
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300834out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835 bh_unlock_sock(sk);
836 sock_put(sk);
837 return;
838drop:
839 kfree_skb(skb);
Arnaldo Carvalho de Melod3894242005-09-22 07:57:21 -0300840 return;
841drop_unlock:
842 kfree_skb(skb);
843 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844}
845
846#undef LLC_REFCNT_DEBUG
847#ifdef LLC_REFCNT_DEBUG
848static atomic_t llc_sock_nr;
849#endif
850
851/**
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 * llc_backlog_rcv - Processes rx frames and expired timers.
853 * @sk: LLC sock (p8022 connection)
854 * @skb: queued rx frame or event
855 *
856 * This function processes frames that has received and timers that has
857 * expired during sending an I pdu (refer to data_req_handler). frames
858 * queue by llc_rcv function (llc_mac.c) and timers queue by timer
859 * callback functions(llc_c_ac.c).
860 */
861static int llc_backlog_rcv(struct sock *sk, struct sk_buff *skb)
862{
863 int rc = 0;
864 struct llc_sock *llc = llc_sk(sk);
865
Arnaldo Carvalho de Meloaf426d32005-09-22 03:59:22 -0300866 if (likely(llc_backlog_type(skb) == LLC_PACKET)) {
867 if (likely(llc->state > 1)) /* not closed */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 rc = llc_conn_rcv(sk, skb);
869 else
870 goto out_kfree_skb;
871 } else if (llc_backlog_type(skb) == LLC_EVENT) {
872 /* timer expiration event */
Arnaldo Carvalho de Meloaf426d32005-09-22 03:59:22 -0300873 if (likely(llc->state > 1)) /* not closed */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874 rc = llc_conn_state_process(sk, skb);
875 else
876 goto out_kfree_skb;
877 } else {
Harvey Harrison0dc47872008-03-05 20:47:47 -0800878 printk(KERN_ERR "%s: invalid skb in backlog\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 goto out_kfree_skb;
880 }
881out:
882 return rc;
883out_kfree_skb:
884 kfree_skb(skb);
885 goto out;
886}
887
888/**
889 * llc_sk_init - Initializes a socket with default llc values.
890 * @sk: socket to initialize.
891 *
892 * Initializes a socket with default llc values.
893 */
Weilong Chen3cdba602013-12-20 11:14:59 +0800894static void llc_sk_init(struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895{
896 struct llc_sock *llc = llc_sk(sk);
897
898 llc->state = LLC_CONN_STATE_ADM;
899 llc->inc_cntr = llc->dec_cntr = 2;
900 llc->dec_step = llc->connect_step = 1;
901
Pavel Emelyanovb24b8a22008-01-23 21:20:07 -0800902 setup_timer(&llc->ack_timer.timer, llc_conn_ack_tmr_cb,
903 (unsigned long)sk);
Arnaldo Carvalho de Melo590232a2005-09-22 04:30:44 -0300904 llc->ack_timer.expire = sysctl_llc2_ack_timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905
Pavel Emelyanovb24b8a22008-01-23 21:20:07 -0800906 setup_timer(&llc->pf_cycle_timer.timer, llc_conn_pf_cycle_tmr_cb,
907 (unsigned long)sk);
Arnaldo Carvalho de Melo590232a2005-09-22 04:30:44 -0300908 llc->pf_cycle_timer.expire = sysctl_llc2_p_timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909
Pavel Emelyanovb24b8a22008-01-23 21:20:07 -0800910 setup_timer(&llc->rej_sent_timer.timer, llc_conn_rej_tmr_cb,
911 (unsigned long)sk);
Arnaldo Carvalho de Melo590232a2005-09-22 04:30:44 -0300912 llc->rej_sent_timer.expire = sysctl_llc2_rej_timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913
Pavel Emelyanovb24b8a22008-01-23 21:20:07 -0800914 setup_timer(&llc->busy_state_timer.timer, llc_conn_busy_tmr_cb,
915 (unsigned long)sk);
Arnaldo Carvalho de Melo590232a2005-09-22 04:30:44 -0300916 llc->busy_state_timer.expire = sysctl_llc2_busy_timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917
918 llc->n2 = 2; /* max retransmit */
919 llc->k = 2; /* tx win size, will adjust dynam */
920 llc->rw = 128; /* rx win size (opt and equal to
YOSHIFUJI Hideakid57b1862007-02-09 23:25:01 +0900921 * tx_win of remote LLC) */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 skb_queue_head_init(&llc->pdu_unack_q);
923 sk->sk_backlog_rcv = llc_backlog_rcv;
924}
925
926/**
927 * llc_sk_alloc - Allocates LLC sock
928 * @family: upper layer protocol family
929 * @priority: for allocation (%GFP_KERNEL, %GFP_ATOMIC, etc)
930 *
931 * Allocates a LLC sock and initializes it. Returns the new LLC sock
932 * or %NULL if there's no memory available for one
933 */
Eric W. Biederman11aa9c22015-05-08 21:09:13 -0500934struct sock *llc_sk_alloc(struct net *net, int family, gfp_t priority, struct proto *prot, int kern)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935{
Eric W. Biederman11aa9c22015-05-08 21:09:13 -0500936 struct sock *sk = sk_alloc(net, family, priority, prot, kern);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937
938 if (!sk)
939 goto out;
940 llc_sk_init(sk);
941 sock_init_data(NULL, sk);
942#ifdef LLC_REFCNT_DEBUG
943 atomic_inc(&llc_sock_nr);
944 printk(KERN_DEBUG "LLC socket %p created in %s, now we have %d alive\n", sk,
Harvey Harrison0dc47872008-03-05 20:47:47 -0800945 __func__, atomic_read(&llc_sock_nr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946#endif
947out:
948 return sk;
949}
950
951/**
952 * llc_sk_free - Frees a LLC socket
953 * @sk - socket to free
954 *
955 * Frees a LLC socket
956 */
957void llc_sk_free(struct sock *sk)
958{
959 struct llc_sock *llc = llc_sk(sk);
960
961 llc->state = LLC_CONN_OUT_OF_SVC;
962 /* Stop all (possibly) running timers */
963 llc_conn_ac_stop_all_timers(sk, NULL);
964#ifdef DEBUG_LLC_CONN_ALLOC
Harvey Harrison0dc47872008-03-05 20:47:47 -0800965 printk(KERN_INFO "%s: unackq=%d, txq=%d\n", __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 skb_queue_len(&llc->pdu_unack_q),
967 skb_queue_len(&sk->sk_write_queue));
968#endif
969 skb_queue_purge(&sk->sk_receive_queue);
970 skb_queue_purge(&sk->sk_write_queue);
971 skb_queue_purge(&llc->pdu_unack_q);
972#ifdef LLC_REFCNT_DEBUG
973 if (atomic_read(&sk->sk_refcnt) != 1) {
974 printk(KERN_DEBUG "Destruction of LLC sock %p delayed in %s, cnt=%d\n",
Harvey Harrison0dc47872008-03-05 20:47:47 -0800975 sk, __func__, atomic_read(&sk->sk_refcnt));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 printk(KERN_DEBUG "%d LLC sockets are still alive\n",
977 atomic_read(&llc_sock_nr));
978 } else {
979 atomic_dec(&llc_sock_nr);
980 printk(KERN_DEBUG "LLC socket %p released in %s, %d are still alive\n", sk,
Harvey Harrison0dc47872008-03-05 20:47:47 -0800981 __func__, atomic_read(&llc_sock_nr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982 }
983#endif
984 sock_put(sk);
985}
986
987/**
988 * llc_sk_reset - resets a connection
989 * @sk: LLC socket to reset
990 *
991 * Resets a connection to the out of service state. Stops its timers
992 * and frees any frames in the queues of the connection.
993 */
994void llc_sk_reset(struct sock *sk)
995{
996 struct llc_sock *llc = llc_sk(sk);
997
998 llc_conn_ac_stop_all_timers(sk, NULL);
999 skb_queue_purge(&sk->sk_write_queue);
1000 skb_queue_purge(&llc->pdu_unack_q);
1001 llc->remote_busy_flag = 0;
1002 llc->cause_flag = 0;
1003 llc->retry_count = 0;
1004 llc_conn_set_p_flag(sk, 0);
1005 llc->f_flag = 0;
1006 llc->s_flag = 0;
1007 llc->ack_pf = 0;
1008 llc->first_pdu_Ns = 0;
1009 llc->ack_must_be_send = 0;
1010 llc->dec_step = 1;
1011 llc->inc_cntr = 2;
1012 llc->dec_cntr = 2;
1013 llc->X = 0;
1014 llc->failed_data_req = 0 ;
1015 llc->last_nr = 0;
1016}