tipc: cosmetic - function names are not to be full sentences
[linux-2.6.git] / net / tipc / link.c
1 /*
2  * net/tipc/link.c: TIPC link code
3  *
4  * Copyright (c) 1996-2007, Ericsson AB
5  * Copyright (c) 2004-2007, 2010-2011, Wind River Systems
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the names of the copyright holders nor the names of its
17  *    contributors may be used to endorse or promote products derived from
18  *    this software without specific prior written permission.
19  *
20  * Alternatively, this software may be distributed under the terms of the
21  * GNU General Public License ("GPL") version 2 as published by the Free
22  * Software Foundation.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  */
36
37 #include "core.h"
38 #include "link.h"
39 #include "port.h"
40 #include "name_distr.h"
41 #include "discover.h"
42 #include "config.h"
43
44
45 /*
46  * Out-of-range value for link session numbers
47  */
48
49 #define INVALID_SESSION 0x10000
50
51 /*
52  * Link state events:
53  */
54
55 #define  STARTING_EVT    856384768      /* link processing trigger */
56 #define  TRAFFIC_MSG_EVT 560815u        /* rx'd ??? */
57 #define  TIMEOUT_EVT     560817u        /* link timer expired */
58
59 /*
60  * The following two 'message types' is really just implementation
61  * data conveniently stored in the message header.
62  * They must not be considered part of the protocol
63  */
64 #define OPEN_MSG   0
65 #define CLOSED_MSG 1
66
67 /*
68  * State value stored in 'exp_msg_count'
69  */
70
71 #define START_CHANGEOVER 100000u
72
73 /**
74  * struct link_name - deconstructed link name
75  * @addr_local: network address of node at this end
76  * @if_local: name of interface at this end
77  * @addr_peer: network address of node at far end
78  * @if_peer: name of interface at far end
79  */
80
81 struct link_name {
82         u32 addr_local;
83         char if_local[TIPC_MAX_IF_NAME];
84         u32 addr_peer;
85         char if_peer[TIPC_MAX_IF_NAME];
86 };
87
88 static void link_handle_out_of_seq_msg(struct link *l_ptr,
89                                        struct sk_buff *buf);
90 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf);
91 static int  link_recv_changeover_msg(struct link **l_ptr, struct sk_buff **buf);
92 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance);
93 static int  link_send_sections_long(struct tipc_port *sender,
94                                     struct iovec const *msg_sect,
95                                     u32 num_sect, u32 destnode);
96 static void link_check_defragm_bufs(struct link *l_ptr);
97 static void link_state_event(struct link *l_ptr, u32 event);
98 static void link_reset_statistics(struct link *l_ptr);
99 static void link_print(struct link *l_ptr, const char *str);
100 static void link_start(struct link *l_ptr);
101 static int link_send_long_buf(struct link *l_ptr, struct sk_buff *buf);
102
103 /*
104  *  Simple link routines
105  */
106
107 static unsigned int align(unsigned int i)
108 {
109         return (i + 3) & ~3u;
110 }
111
112 static void link_init_max_pkt(struct link *l_ptr)
113 {
114         u32 max_pkt;
115
116         max_pkt = (l_ptr->b_ptr->mtu & ~3);
117         if (max_pkt > MAX_MSG_SIZE)
118                 max_pkt = MAX_MSG_SIZE;
119
120         l_ptr->max_pkt_target = max_pkt;
121         if (l_ptr->max_pkt_target < MAX_PKT_DEFAULT)
122                 l_ptr->max_pkt = l_ptr->max_pkt_target;
123         else
124                 l_ptr->max_pkt = MAX_PKT_DEFAULT;
125
126         l_ptr->max_pkt_probes = 0;
127 }
128
129 static u32 link_next_sent(struct link *l_ptr)
130 {
131         if (l_ptr->next_out)
132                 return msg_seqno(buf_msg(l_ptr->next_out));
133         return mod(l_ptr->next_out_no);
134 }
135
136 static u32 link_last_sent(struct link *l_ptr)
137 {
138         return mod(link_next_sent(l_ptr) - 1);
139 }
140
141 /*
142  *  Simple non-static link routines (i.e. referenced outside this file)
143  */
144
145 int tipc_link_is_up(struct link *l_ptr)
146 {
147         if (!l_ptr)
148                 return 0;
149         return link_working_working(l_ptr) || link_working_unknown(l_ptr);
150 }
151
152 int tipc_link_is_active(struct link *l_ptr)
153 {
154         return  (l_ptr->owner->active_links[0] == l_ptr) ||
155                 (l_ptr->owner->active_links[1] == l_ptr);
156 }
157
158 /**
159  * link_name_validate - validate & (optionally) deconstruct link name
160  * @name - ptr to link name string
161  * @name_parts - ptr to area for link name components (or NULL if not needed)
162  *
163  * Returns 1 if link name is valid, otherwise 0.
164  */
165
166 static int link_name_validate(const char *name, struct link_name *name_parts)
167 {
168         char name_copy[TIPC_MAX_LINK_NAME];
169         char *addr_local;
170         char *if_local;
171         char *addr_peer;
172         char *if_peer;
173         char dummy;
174         u32 z_local, c_local, n_local;
175         u32 z_peer, c_peer, n_peer;
176         u32 if_local_len;
177         u32 if_peer_len;
178
179         /* copy link name & ensure length is OK */
180
181         name_copy[TIPC_MAX_LINK_NAME - 1] = 0;
182         /* need above in case non-Posix strncpy() doesn't pad with nulls */
183         strncpy(name_copy, name, TIPC_MAX_LINK_NAME);
184         if (name_copy[TIPC_MAX_LINK_NAME - 1] != 0)
185                 return 0;
186
187         /* ensure all component parts of link name are present */
188
189         addr_local = name_copy;
190         if_local = strchr(addr_local, ':');
191         if (if_local == NULL)
192                 return 0;
193         *(if_local++) = 0;
194         addr_peer = strchr(if_local, '-');
195         if (addr_peer == NULL)
196                 return 0;
197         *(addr_peer++) = 0;
198         if_local_len = addr_peer - if_local;
199         if_peer = strchr(addr_peer, ':');
200         if (if_peer == NULL)
201                 return 0;
202         *(if_peer++) = 0;
203         if_peer_len = strlen(if_peer) + 1;
204
205         /* validate component parts of link name */
206
207         if ((sscanf(addr_local, "%u.%u.%u%c",
208                     &z_local, &c_local, &n_local, &dummy) != 3) ||
209             (sscanf(addr_peer, "%u.%u.%u%c",
210                     &z_peer, &c_peer, &n_peer, &dummy) != 3) ||
211             (z_local > 255) || (c_local > 4095) || (n_local > 4095) ||
212             (z_peer  > 255) || (c_peer  > 4095) || (n_peer  > 4095) ||
213             (if_local_len <= 1) || (if_local_len > TIPC_MAX_IF_NAME) ||
214             (if_peer_len  <= 1) || (if_peer_len  > TIPC_MAX_IF_NAME) ||
215             (strspn(if_local, tipc_alphabet) != (if_local_len - 1)) ||
216             (strspn(if_peer, tipc_alphabet) != (if_peer_len - 1)))
217                 return 0;
218
219         /* return link name components, if necessary */
220
221         if (name_parts) {
222                 name_parts->addr_local = tipc_addr(z_local, c_local, n_local);
223                 strcpy(name_parts->if_local, if_local);
224                 name_parts->addr_peer = tipc_addr(z_peer, c_peer, n_peer);
225                 strcpy(name_parts->if_peer, if_peer);
226         }
227         return 1;
228 }
229
230 /**
231  * link_timeout - handle expiration of link timer
232  * @l_ptr: pointer to link
233  *
234  * This routine must not grab "tipc_net_lock" to avoid a potential deadlock conflict
235  * with tipc_link_delete().  (There is no risk that the node will be deleted by
236  * another thread because tipc_link_delete() always cancels the link timer before
237  * tipc_node_delete() is called.)
238  */
239
240 static void link_timeout(struct link *l_ptr)
241 {
242         tipc_node_lock(l_ptr->owner);
243
244         /* update counters used in statistical profiling of send traffic */
245
246         l_ptr->stats.accu_queue_sz += l_ptr->out_queue_size;
247         l_ptr->stats.queue_sz_counts++;
248
249         if (l_ptr->first_out) {
250                 struct tipc_msg *msg = buf_msg(l_ptr->first_out);
251                 u32 length = msg_size(msg);
252
253                 if ((msg_user(msg) == MSG_FRAGMENTER) &&
254                     (msg_type(msg) == FIRST_FRAGMENT)) {
255                         length = msg_size(msg_get_wrapped(msg));
256                 }
257                 if (length) {
258                         l_ptr->stats.msg_lengths_total += length;
259                         l_ptr->stats.msg_length_counts++;
260                         if (length <= 64)
261                                 l_ptr->stats.msg_length_profile[0]++;
262                         else if (length <= 256)
263                                 l_ptr->stats.msg_length_profile[1]++;
264                         else if (length <= 1024)
265                                 l_ptr->stats.msg_length_profile[2]++;
266                         else if (length <= 4096)
267                                 l_ptr->stats.msg_length_profile[3]++;
268                         else if (length <= 16384)
269                                 l_ptr->stats.msg_length_profile[4]++;
270                         else if (length <= 32768)
271                                 l_ptr->stats.msg_length_profile[5]++;
272                         else
273                                 l_ptr->stats.msg_length_profile[6]++;
274                 }
275         }
276
277         /* do all other link processing performed on a periodic basis */
278
279         link_check_defragm_bufs(l_ptr);
280
281         link_state_event(l_ptr, TIMEOUT_EVT);
282
283         if (l_ptr->next_out)
284                 tipc_link_push_queue(l_ptr);
285
286         tipc_node_unlock(l_ptr->owner);
287 }
288
289 static void link_set_timer(struct link *l_ptr, u32 time)
290 {
291         k_start_timer(&l_ptr->timer, time);
292 }
293
294 /**
295  * tipc_link_create - create a new link
296  * @b_ptr: pointer to associated bearer
297  * @peer: network address of node at other end of link
298  * @media_addr: media address to use when sending messages over link
299  *
300  * Returns pointer to link.
301  */
302
303 struct link *tipc_link_create(struct tipc_bearer *b_ptr, const u32 peer,
304                               const struct tipc_media_addr *media_addr)
305 {
306         struct link *l_ptr;
307         struct tipc_msg *msg;
308         char *if_name;
309
310         l_ptr = kzalloc(sizeof(*l_ptr), GFP_ATOMIC);
311         if (!l_ptr) {
312                 warn("Link creation failed, no memory\n");
313                 return NULL;
314         }
315
316         l_ptr->addr = peer;
317         if_name = strchr(b_ptr->name, ':') + 1;
318         sprintf(l_ptr->name, "%u.%u.%u:%s-%u.%u.%u:",
319                 tipc_zone(tipc_own_addr), tipc_cluster(tipc_own_addr),
320                 tipc_node(tipc_own_addr),
321                 if_name,
322                 tipc_zone(peer), tipc_cluster(peer), tipc_node(peer));
323                 /* note: peer i/f is appended to link name by reset/activate */
324         memcpy(&l_ptr->media_addr, media_addr, sizeof(*media_addr));
325         l_ptr->checkpoint = 1;
326         l_ptr->b_ptr = b_ptr;
327         link_set_supervision_props(l_ptr, b_ptr->media->tolerance);
328         l_ptr->state = RESET_UNKNOWN;
329
330         l_ptr->pmsg = (struct tipc_msg *)&l_ptr->proto_msg;
331         msg = l_ptr->pmsg;
332         tipc_msg_init(msg, LINK_PROTOCOL, RESET_MSG, INT_H_SIZE, l_ptr->addr);
333         msg_set_size(msg, sizeof(l_ptr->proto_msg));
334         msg_set_session(msg, (tipc_random & 0xffff));
335         msg_set_bearer_id(msg, b_ptr->identity);
336         strcpy((char *)msg_data(msg), if_name);
337
338         l_ptr->priority = b_ptr->priority;
339         tipc_link_set_queue_limits(l_ptr, b_ptr->media->window);
340
341         link_init_max_pkt(l_ptr);
342
343         l_ptr->next_out_no = 1;
344         INIT_LIST_HEAD(&l_ptr->waiting_ports);
345
346         link_reset_statistics(l_ptr);
347
348         l_ptr->owner = tipc_node_attach_link(l_ptr);
349         if (!l_ptr->owner) {
350                 kfree(l_ptr);
351                 return NULL;
352         }
353
354         k_init_timer(&l_ptr->timer, (Handler)link_timeout, (unsigned long)l_ptr);
355         list_add_tail(&l_ptr->link_list, &b_ptr->links);
356         tipc_k_signal((Handler)link_start, (unsigned long)l_ptr);
357
358         return l_ptr;
359 }
360
361 /**
362  * tipc_link_delete - delete a link
363  * @l_ptr: pointer to link
364  *
365  * Note: 'tipc_net_lock' is write_locked, bearer is locked.
366  * This routine must not grab the node lock until after link timer cancellation
367  * to avoid a potential deadlock situation.
368  */
369
370 void tipc_link_delete(struct link *l_ptr)
371 {
372         if (!l_ptr) {
373                 err("Attempt to delete non-existent link\n");
374                 return;
375         }
376
377         k_cancel_timer(&l_ptr->timer);
378
379         tipc_node_lock(l_ptr->owner);
380         tipc_link_reset(l_ptr);
381         tipc_node_detach_link(l_ptr->owner, l_ptr);
382         tipc_link_stop(l_ptr);
383         list_del_init(&l_ptr->link_list);
384         tipc_node_unlock(l_ptr->owner);
385         k_term_timer(&l_ptr->timer);
386         kfree(l_ptr);
387 }
388
389 static void link_start(struct link *l_ptr)
390 {
391         tipc_node_lock(l_ptr->owner);
392         link_state_event(l_ptr, STARTING_EVT);
393         tipc_node_unlock(l_ptr->owner);
394 }
395
396 /**
397  * link_schedule_port - schedule port for deferred sending
398  * @l_ptr: pointer to link
399  * @origport: reference to sending port
400  * @sz: amount of data to be sent
401  *
402  * Schedules port for renewed sending of messages after link congestion
403  * has abated.
404  */
405
406 static int link_schedule_port(struct link *l_ptr, u32 origport, u32 sz)
407 {
408         struct tipc_port *p_ptr;
409
410         spin_lock_bh(&tipc_port_list_lock);
411         p_ptr = tipc_port_lock(origport);
412         if (p_ptr) {
413                 if (!p_ptr->wakeup)
414                         goto exit;
415                 if (!list_empty(&p_ptr->wait_list))
416                         goto exit;
417                 p_ptr->congested = 1;
418                 p_ptr->waiting_pkts = 1 + ((sz - 1) / l_ptr->max_pkt);
419                 list_add_tail(&p_ptr->wait_list, &l_ptr->waiting_ports);
420                 l_ptr->stats.link_congs++;
421 exit:
422                 tipc_port_unlock(p_ptr);
423         }
424         spin_unlock_bh(&tipc_port_list_lock);
425         return -ELINKCONG;
426 }
427
428 void tipc_link_wakeup_ports(struct link *l_ptr, int all)
429 {
430         struct tipc_port *p_ptr;
431         struct tipc_port *temp_p_ptr;
432         int win = l_ptr->queue_limit[0] - l_ptr->out_queue_size;
433
434         if (all)
435                 win = 100000;
436         if (win <= 0)
437                 return;
438         if (!spin_trylock_bh(&tipc_port_list_lock))
439                 return;
440         if (link_congested(l_ptr))
441                 goto exit;
442         list_for_each_entry_safe(p_ptr, temp_p_ptr, &l_ptr->waiting_ports,
443                                  wait_list) {
444                 if (win <= 0)
445                         break;
446                 list_del_init(&p_ptr->wait_list);
447                 spin_lock_bh(p_ptr->lock);
448                 p_ptr->congested = 0;
449                 p_ptr->wakeup(p_ptr);
450                 win -= p_ptr->waiting_pkts;
451                 spin_unlock_bh(p_ptr->lock);
452         }
453
454 exit:
455         spin_unlock_bh(&tipc_port_list_lock);
456 }
457
458 /**
459  * link_release_outqueue - purge link's outbound message queue
460  * @l_ptr: pointer to link
461  */
462
463 static void link_release_outqueue(struct link *l_ptr)
464 {
465         struct sk_buff *buf = l_ptr->first_out;
466         struct sk_buff *next;
467
468         while (buf) {
469                 next = buf->next;
470                 buf_discard(buf);
471                 buf = next;
472         }
473         l_ptr->first_out = NULL;
474         l_ptr->out_queue_size = 0;
475 }
476
477 /**
478  * tipc_link_reset_fragments - purge link's inbound message fragments queue
479  * @l_ptr: pointer to link
480  */
481
482 void tipc_link_reset_fragments(struct link *l_ptr)
483 {
484         struct sk_buff *buf = l_ptr->defragm_buf;
485         struct sk_buff *next;
486
487         while (buf) {
488                 next = buf->next;
489                 buf_discard(buf);
490                 buf = next;
491         }
492         l_ptr->defragm_buf = NULL;
493 }
494
495 /**
496  * tipc_link_stop - purge all inbound and outbound messages associated with link
497  * @l_ptr: pointer to link
498  */
499
500 void tipc_link_stop(struct link *l_ptr)
501 {
502         struct sk_buff *buf;
503         struct sk_buff *next;
504
505         buf = l_ptr->oldest_deferred_in;
506         while (buf) {
507                 next = buf->next;
508                 buf_discard(buf);
509                 buf = next;
510         }
511
512         buf = l_ptr->first_out;
513         while (buf) {
514                 next = buf->next;
515                 buf_discard(buf);
516                 buf = next;
517         }
518
519         tipc_link_reset_fragments(l_ptr);
520
521         buf_discard(l_ptr->proto_msg_queue);
522         l_ptr->proto_msg_queue = NULL;
523 }
524
525 /* LINK EVENT CODE IS NOT SUPPORTED AT PRESENT */
526 #define link_send_event(fcn, l_ptr, up) do { } while (0)
527
528 void tipc_link_reset(struct link *l_ptr)
529 {
530         struct sk_buff *buf;
531         u32 prev_state = l_ptr->state;
532         u32 checkpoint = l_ptr->next_in_no;
533         int was_active_link = tipc_link_is_active(l_ptr);
534
535         msg_set_session(l_ptr->pmsg, ((msg_session(l_ptr->pmsg) + 1) & 0xffff));
536
537         /* Link is down, accept any session */
538         l_ptr->peer_session = INVALID_SESSION;
539
540         /* Prepare for max packet size negotiation */
541         link_init_max_pkt(l_ptr);
542
543         l_ptr->state = RESET_UNKNOWN;
544
545         if ((prev_state == RESET_UNKNOWN) || (prev_state == RESET_RESET))
546                 return;
547
548         tipc_node_link_down(l_ptr->owner, l_ptr);
549         tipc_bearer_remove_dest(l_ptr->b_ptr, l_ptr->addr);
550
551         if (was_active_link && tipc_node_active_links(l_ptr->owner) &&
552             l_ptr->owner->permit_changeover) {
553                 l_ptr->reset_checkpoint = checkpoint;
554                 l_ptr->exp_msg_count = START_CHANGEOVER;
555         }
556
557         /* Clean up all queues: */
558
559         link_release_outqueue(l_ptr);
560         buf_discard(l_ptr->proto_msg_queue);
561         l_ptr->proto_msg_queue = NULL;
562         buf = l_ptr->oldest_deferred_in;
563         while (buf) {
564                 struct sk_buff *next = buf->next;
565                 buf_discard(buf);
566                 buf = next;
567         }
568         if (!list_empty(&l_ptr->waiting_ports))
569                 tipc_link_wakeup_ports(l_ptr, 1);
570
571         l_ptr->retransm_queue_head = 0;
572         l_ptr->retransm_queue_size = 0;
573         l_ptr->last_out = NULL;
574         l_ptr->first_out = NULL;
575         l_ptr->next_out = NULL;
576         l_ptr->unacked_window = 0;
577         l_ptr->checkpoint = 1;
578         l_ptr->next_out_no = 1;
579         l_ptr->deferred_inqueue_sz = 0;
580         l_ptr->oldest_deferred_in = NULL;
581         l_ptr->newest_deferred_in = NULL;
582         l_ptr->fsm_msg_cnt = 0;
583         l_ptr->stale_count = 0;
584         link_reset_statistics(l_ptr);
585
586         link_send_event(tipc_cfg_link_event, l_ptr, 0);
587         if (!in_own_cluster(l_ptr->addr))
588                 link_send_event(tipc_disc_link_event, l_ptr, 0);
589 }
590
591
592 static void link_activate(struct link *l_ptr)
593 {
594         l_ptr->next_in_no = l_ptr->stats.recv_info = 1;
595         tipc_node_link_up(l_ptr->owner, l_ptr);
596         tipc_bearer_add_dest(l_ptr->b_ptr, l_ptr->addr);
597         link_send_event(tipc_cfg_link_event, l_ptr, 1);
598         if (!in_own_cluster(l_ptr->addr))
599                 link_send_event(tipc_disc_link_event, l_ptr, 1);
600 }
601
602 /**
603  * link_state_event - link finite state machine
604  * @l_ptr: pointer to link
605  * @event: state machine event to process
606  */
607
608 static void link_state_event(struct link *l_ptr, unsigned event)
609 {
610         struct link *other;
611         u32 cont_intv = l_ptr->continuity_interval;
612
613         if (!l_ptr->started && (event != STARTING_EVT))
614                 return;         /* Not yet. */
615
616         if (link_blocked(l_ptr)) {
617                 if (event == TIMEOUT_EVT)
618                         link_set_timer(l_ptr, cont_intv);
619                 return;   /* Changeover going on */
620         }
621
622         switch (l_ptr->state) {
623         case WORKING_WORKING:
624                 switch (event) {
625                 case TRAFFIC_MSG_EVT:
626                 case ACTIVATE_MSG:
627                         break;
628                 case TIMEOUT_EVT:
629                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
630                                 l_ptr->checkpoint = l_ptr->next_in_no;
631                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
632                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
633                                                                  0, 0, 0, 0, 0);
634                                         l_ptr->fsm_msg_cnt++;
635                                 } else if (l_ptr->max_pkt < l_ptr->max_pkt_target) {
636                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
637                                                                  1, 0, 0, 0, 0);
638                                         l_ptr->fsm_msg_cnt++;
639                                 }
640                                 link_set_timer(l_ptr, cont_intv);
641                                 break;
642                         }
643                         l_ptr->state = WORKING_UNKNOWN;
644                         l_ptr->fsm_msg_cnt = 0;
645                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
646                         l_ptr->fsm_msg_cnt++;
647                         link_set_timer(l_ptr, cont_intv / 4);
648                         break;
649                 case RESET_MSG:
650                         info("Resetting link <%s>, requested by peer\n",
651                              l_ptr->name);
652                         tipc_link_reset(l_ptr);
653                         l_ptr->state = RESET_RESET;
654                         l_ptr->fsm_msg_cnt = 0;
655                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
656                         l_ptr->fsm_msg_cnt++;
657                         link_set_timer(l_ptr, cont_intv);
658                         break;
659                 default:
660                         err("Unknown link event %u in WW state\n", event);
661                 }
662                 break;
663         case WORKING_UNKNOWN:
664                 switch (event) {
665                 case TRAFFIC_MSG_EVT:
666                 case ACTIVATE_MSG:
667                         l_ptr->state = WORKING_WORKING;
668                         l_ptr->fsm_msg_cnt = 0;
669                         link_set_timer(l_ptr, cont_intv);
670                         break;
671                 case RESET_MSG:
672                         info("Resetting link <%s>, requested by peer "
673                              "while probing\n", l_ptr->name);
674                         tipc_link_reset(l_ptr);
675                         l_ptr->state = RESET_RESET;
676                         l_ptr->fsm_msg_cnt = 0;
677                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
678                         l_ptr->fsm_msg_cnt++;
679                         link_set_timer(l_ptr, cont_intv);
680                         break;
681                 case TIMEOUT_EVT:
682                         if (l_ptr->next_in_no != l_ptr->checkpoint) {
683                                 l_ptr->state = WORKING_WORKING;
684                                 l_ptr->fsm_msg_cnt = 0;
685                                 l_ptr->checkpoint = l_ptr->next_in_no;
686                                 if (tipc_bclink_acks_missing(l_ptr->owner)) {
687                                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
688                                                                  0, 0, 0, 0, 0);
689                                         l_ptr->fsm_msg_cnt++;
690                                 }
691                                 link_set_timer(l_ptr, cont_intv);
692                         } else if (l_ptr->fsm_msg_cnt < l_ptr->abort_limit) {
693                                 tipc_link_send_proto_msg(l_ptr, STATE_MSG,
694                                                          1, 0, 0, 0, 0);
695                                 l_ptr->fsm_msg_cnt++;
696                                 link_set_timer(l_ptr, cont_intv / 4);
697                         } else {        /* Link has failed */
698                                 warn("Resetting link <%s>, peer not responding\n",
699                                      l_ptr->name);
700                                 tipc_link_reset(l_ptr);
701                                 l_ptr->state = RESET_UNKNOWN;
702                                 l_ptr->fsm_msg_cnt = 0;
703                                 tipc_link_send_proto_msg(l_ptr, RESET_MSG,
704                                                          0, 0, 0, 0, 0);
705                                 l_ptr->fsm_msg_cnt++;
706                                 link_set_timer(l_ptr, cont_intv);
707                         }
708                         break;
709                 default:
710                         err("Unknown link event %u in WU state\n", event);
711                 }
712                 break;
713         case RESET_UNKNOWN:
714                 switch (event) {
715                 case TRAFFIC_MSG_EVT:
716                         break;
717                 case ACTIVATE_MSG:
718                         other = l_ptr->owner->active_links[0];
719                         if (other && link_working_unknown(other))
720                                 break;
721                         l_ptr->state = WORKING_WORKING;
722                         l_ptr->fsm_msg_cnt = 0;
723                         link_activate(l_ptr);
724                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
725                         l_ptr->fsm_msg_cnt++;
726                         link_set_timer(l_ptr, cont_intv);
727                         break;
728                 case RESET_MSG:
729                         l_ptr->state = RESET_RESET;
730                         l_ptr->fsm_msg_cnt = 0;
731                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 1, 0, 0, 0, 0);
732                         l_ptr->fsm_msg_cnt++;
733                         link_set_timer(l_ptr, cont_intv);
734                         break;
735                 case STARTING_EVT:
736                         l_ptr->started = 1;
737                         /* fall through */
738                 case TIMEOUT_EVT:
739                         tipc_link_send_proto_msg(l_ptr, RESET_MSG, 0, 0, 0, 0, 0);
740                         l_ptr->fsm_msg_cnt++;
741                         link_set_timer(l_ptr, cont_intv);
742                         break;
743                 default:
744                         err("Unknown link event %u in RU state\n", event);
745                 }
746                 break;
747         case RESET_RESET:
748                 switch (event) {
749                 case TRAFFIC_MSG_EVT:
750                 case ACTIVATE_MSG:
751                         other = l_ptr->owner->active_links[0];
752                         if (other && link_working_unknown(other))
753                                 break;
754                         l_ptr->state = WORKING_WORKING;
755                         l_ptr->fsm_msg_cnt = 0;
756                         link_activate(l_ptr);
757                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 1, 0, 0, 0, 0);
758                         l_ptr->fsm_msg_cnt++;
759                         link_set_timer(l_ptr, cont_intv);
760                         break;
761                 case RESET_MSG:
762                         break;
763                 case TIMEOUT_EVT:
764                         tipc_link_send_proto_msg(l_ptr, ACTIVATE_MSG, 0, 0, 0, 0, 0);
765                         l_ptr->fsm_msg_cnt++;
766                         link_set_timer(l_ptr, cont_intv);
767                         break;
768                 default:
769                         err("Unknown link event %u in RR state\n", event);
770                 }
771                 break;
772         default:
773                 err("Unknown link state %u/%u\n", l_ptr->state, event);
774         }
775 }
776
777 /*
778  * link_bundle_buf(): Append contents of a buffer to
779  * the tail of an existing one.
780  */
781
782 static int link_bundle_buf(struct link *l_ptr,
783                            struct sk_buff *bundler,
784                            struct sk_buff *buf)
785 {
786         struct tipc_msg *bundler_msg = buf_msg(bundler);
787         struct tipc_msg *msg = buf_msg(buf);
788         u32 size = msg_size(msg);
789         u32 bundle_size = msg_size(bundler_msg);
790         u32 to_pos = align(bundle_size);
791         u32 pad = to_pos - bundle_size;
792
793         if (msg_user(bundler_msg) != MSG_BUNDLER)
794                 return 0;
795         if (msg_type(bundler_msg) != OPEN_MSG)
796                 return 0;
797         if (skb_tailroom(bundler) < (pad + size))
798                 return 0;
799         if (l_ptr->max_pkt < (to_pos + size))
800                 return 0;
801
802         skb_put(bundler, pad + size);
803         skb_copy_to_linear_data_offset(bundler, to_pos, buf->data, size);
804         msg_set_size(bundler_msg, to_pos + size);
805         msg_set_msgcnt(bundler_msg, msg_msgcnt(bundler_msg) + 1);
806         buf_discard(buf);
807         l_ptr->stats.sent_bundled++;
808         return 1;
809 }
810
811 static void link_add_to_outqueue(struct link *l_ptr,
812                                  struct sk_buff *buf,
813                                  struct tipc_msg *msg)
814 {
815         u32 ack = mod(l_ptr->next_in_no - 1);
816         u32 seqno = mod(l_ptr->next_out_no++);
817
818         msg_set_word(msg, 2, ((ack << 16) | seqno));
819         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
820         buf->next = NULL;
821         if (l_ptr->first_out) {
822                 l_ptr->last_out->next = buf;
823                 l_ptr->last_out = buf;
824         } else
825                 l_ptr->first_out = l_ptr->last_out = buf;
826
827         l_ptr->out_queue_size++;
828         if (l_ptr->out_queue_size > l_ptr->stats.max_queue_sz)
829                 l_ptr->stats.max_queue_sz = l_ptr->out_queue_size;
830 }
831
832 /*
833  * tipc_link_send_buf() is the 'full path' for messages, called from
834  * inside TIPC when the 'fast path' in tipc_send_buf
835  * has failed, and from link_send()
836  */
837
838 int tipc_link_send_buf(struct link *l_ptr, struct sk_buff *buf)
839 {
840         struct tipc_msg *msg = buf_msg(buf);
841         u32 size = msg_size(msg);
842         u32 dsz = msg_data_sz(msg);
843         u32 queue_size = l_ptr->out_queue_size;
844         u32 imp = tipc_msg_tot_importance(msg);
845         u32 queue_limit = l_ptr->queue_limit[imp];
846         u32 max_packet = l_ptr->max_pkt;
847
848         msg_set_prevnode(msg, tipc_own_addr);   /* If routed message */
849
850         /* Match msg importance against queue limits: */
851
852         if (unlikely(queue_size >= queue_limit)) {
853                 if (imp <= TIPC_CRITICAL_IMPORTANCE) {
854                         return link_schedule_port(l_ptr, msg_origport(msg),
855                                                   size);
856                 }
857                 buf_discard(buf);
858                 if (imp > CONN_MANAGER) {
859                         warn("Resetting link <%s>, send queue full", l_ptr->name);
860                         tipc_link_reset(l_ptr);
861                 }
862                 return dsz;
863         }
864
865         /* Fragmentation needed ? */
866
867         if (size > max_packet)
868                 return link_send_long_buf(l_ptr, buf);
869
870         /* Packet can be queued or sent: */
871
872         if (likely(!tipc_bearer_congested(l_ptr->b_ptr, l_ptr) &&
873                    !link_congested(l_ptr))) {
874                 link_add_to_outqueue(l_ptr, buf, msg);
875
876                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr))) {
877                         l_ptr->unacked_window = 0;
878                 } else {
879                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
880                         l_ptr->stats.bearer_congs++;
881                         l_ptr->next_out = buf;
882                 }
883                 return dsz;
884         }
885         /* Congestion: can message be bundled ?: */
886
887         if ((msg_user(msg) != CHANGEOVER_PROTOCOL) &&
888             (msg_user(msg) != MSG_FRAGMENTER)) {
889
890                 /* Try adding message to an existing bundle */
891
892                 if (l_ptr->next_out &&
893                     link_bundle_buf(l_ptr, l_ptr->last_out, buf)) {
894                         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
895                         return dsz;
896                 }
897
898                 /* Try creating a new bundle */
899
900                 if (size <= max_packet * 2 / 3) {
901                         struct sk_buff *bundler = tipc_buf_acquire(max_packet);
902                         struct tipc_msg bundler_hdr;
903
904                         if (bundler) {
905                                 tipc_msg_init(&bundler_hdr, MSG_BUNDLER, OPEN_MSG,
906                                          INT_H_SIZE, l_ptr->addr);
907                                 skb_copy_to_linear_data(bundler, &bundler_hdr,
908                                                         INT_H_SIZE);
909                                 skb_trim(bundler, INT_H_SIZE);
910                                 link_bundle_buf(l_ptr, bundler, buf);
911                                 buf = bundler;
912                                 msg = buf_msg(buf);
913                                 l_ptr->stats.sent_bundles++;
914                         }
915                 }
916         }
917         if (!l_ptr->next_out)
918                 l_ptr->next_out = buf;
919         link_add_to_outqueue(l_ptr, buf, msg);
920         tipc_bearer_resolve_congestion(l_ptr->b_ptr, l_ptr);
921         return dsz;
922 }
923
924 /*
925  * tipc_link_send(): same as tipc_link_send_buf(), but the link to use has
926  * not been selected yet, and the the owner node is not locked
927  * Called by TIPC internal users, e.g. the name distributor
928  */
929
930 int tipc_link_send(struct sk_buff *buf, u32 dest, u32 selector)
931 {
932         struct link *l_ptr;
933         struct tipc_node *n_ptr;
934         int res = -ELINKCONG;
935
936         read_lock_bh(&tipc_net_lock);
937         n_ptr = tipc_node_find(dest);
938         if (n_ptr) {
939                 tipc_node_lock(n_ptr);
940                 l_ptr = n_ptr->active_links[selector & 1];
941                 if (l_ptr)
942                         res = tipc_link_send_buf(l_ptr, buf);
943                 else
944                         buf_discard(buf);
945                 tipc_node_unlock(n_ptr);
946         } else {
947                 buf_discard(buf);
948         }
949         read_unlock_bh(&tipc_net_lock);
950         return res;
951 }
952
953 /*
954  * link_send_buf_fast: Entry for data messages where the
955  * destination link is known and the header is complete,
956  * inclusive total message length. Very time critical.
957  * Link is locked. Returns user data length.
958  */
959
960 static int link_send_buf_fast(struct link *l_ptr, struct sk_buff *buf,
961                               u32 *used_max_pkt)
962 {
963         struct tipc_msg *msg = buf_msg(buf);
964         int res = msg_data_sz(msg);
965
966         if (likely(!link_congested(l_ptr))) {
967                 if (likely(msg_size(msg) <= l_ptr->max_pkt)) {
968                         if (likely(list_empty(&l_ptr->b_ptr->cong_links))) {
969                                 link_add_to_outqueue(l_ptr, buf, msg);
970                                 if (likely(tipc_bearer_send(l_ptr->b_ptr, buf,
971                                                             &l_ptr->media_addr))) {
972                                         l_ptr->unacked_window = 0;
973                                         return res;
974                                 }
975                                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
976                                 l_ptr->stats.bearer_congs++;
977                                 l_ptr->next_out = buf;
978                                 return res;
979                         }
980                 } else
981                         *used_max_pkt = l_ptr->max_pkt;
982         }
983         return tipc_link_send_buf(l_ptr, buf);  /* All other cases */
984 }
985
986 /*
987  * tipc_send_buf_fast: Entry for data messages where the
988  * destination node is known and the header is complete,
989  * inclusive total message length.
990  * Returns user data length.
991  */
992 int tipc_send_buf_fast(struct sk_buff *buf, u32 destnode)
993 {
994         struct link *l_ptr;
995         struct tipc_node *n_ptr;
996         int res;
997         u32 selector = msg_origport(buf_msg(buf)) & 1;
998         u32 dummy;
999
1000         if (destnode == tipc_own_addr)
1001                 return tipc_port_recv_msg(buf);
1002
1003         read_lock_bh(&tipc_net_lock);
1004         n_ptr = tipc_node_find(destnode);
1005         if (likely(n_ptr)) {
1006                 tipc_node_lock(n_ptr);
1007                 l_ptr = n_ptr->active_links[selector];
1008                 if (likely(l_ptr)) {
1009                         res = link_send_buf_fast(l_ptr, buf, &dummy);
1010                         tipc_node_unlock(n_ptr);
1011                         read_unlock_bh(&tipc_net_lock);
1012                         return res;
1013                 }
1014                 tipc_node_unlock(n_ptr);
1015         }
1016         read_unlock_bh(&tipc_net_lock);
1017         res = msg_data_sz(buf_msg(buf));
1018         tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1019         return res;
1020 }
1021
1022
1023 /*
1024  * tipc_link_send_sections_fast: Entry for messages where the
1025  * destination processor is known and the header is complete,
1026  * except for total message length.
1027  * Returns user data length or errno.
1028  */
1029 int tipc_link_send_sections_fast(struct tipc_port *sender,
1030                                  struct iovec const *msg_sect,
1031                                  const u32 num_sect,
1032                                  u32 destaddr)
1033 {
1034         struct tipc_msg *hdr = &sender->phdr;
1035         struct link *l_ptr;
1036         struct sk_buff *buf;
1037         struct tipc_node *node;
1038         int res;
1039         u32 selector = msg_origport(hdr) & 1;
1040
1041 again:
1042         /*
1043          * Try building message using port's max_pkt hint.
1044          * (Must not hold any locks while building message.)
1045          */
1046
1047         res = tipc_msg_build(hdr, msg_sect, num_sect, sender->max_pkt,
1048                         !sender->user_port, &buf);
1049
1050         read_lock_bh(&tipc_net_lock);
1051         node = tipc_node_find(destaddr);
1052         if (likely(node)) {
1053                 tipc_node_lock(node);
1054                 l_ptr = node->active_links[selector];
1055                 if (likely(l_ptr)) {
1056                         if (likely(buf)) {
1057                                 res = link_send_buf_fast(l_ptr, buf,
1058                                                          &sender->max_pkt);
1059                                 if (unlikely(res < 0))
1060                                         buf_discard(buf);
1061 exit:
1062                                 tipc_node_unlock(node);
1063                                 read_unlock_bh(&tipc_net_lock);
1064                                 return res;
1065                         }
1066
1067                         /* Exit if build request was invalid */
1068
1069                         if (unlikely(res < 0))
1070                                 goto exit;
1071
1072                         /* Exit if link (or bearer) is congested */
1073
1074                         if (link_congested(l_ptr) ||
1075                             !list_empty(&l_ptr->b_ptr->cong_links)) {
1076                                 res = link_schedule_port(l_ptr,
1077                                                          sender->ref, res);
1078                                 goto exit;
1079                         }
1080
1081                         /*
1082                          * Message size exceeds max_pkt hint; update hint,
1083                          * then re-try fast path or fragment the message
1084                          */
1085
1086                         sender->max_pkt = l_ptr->max_pkt;
1087                         tipc_node_unlock(node);
1088                         read_unlock_bh(&tipc_net_lock);
1089
1090
1091                         if ((msg_hdr_sz(hdr) + res) <= sender->max_pkt)
1092                                 goto again;
1093
1094                         return link_send_sections_long(sender, msg_sect,
1095                                                        num_sect, destaddr);
1096                 }
1097                 tipc_node_unlock(node);
1098         }
1099         read_unlock_bh(&tipc_net_lock);
1100
1101         /* Couldn't find a link to the destination node */
1102
1103         if (buf)
1104                 return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
1105         if (res >= 0)
1106                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1107                                                  TIPC_ERR_NO_NODE);
1108         return res;
1109 }
1110
1111 /*
1112  * link_send_sections_long(): Entry for long messages where the
1113  * destination node is known and the header is complete,
1114  * inclusive total message length.
1115  * Link and bearer congestion status have been checked to be ok,
1116  * and are ignored if they change.
1117  *
1118  * Note that fragments do not use the full link MTU so that they won't have
1119  * to undergo refragmentation if link changeover causes them to be sent
1120  * over another link with an additional tunnel header added as prefix.
1121  * (Refragmentation will still occur if the other link has a smaller MTU.)
1122  *
1123  * Returns user data length or errno.
1124  */
1125 static int link_send_sections_long(struct tipc_port *sender,
1126                                    struct iovec const *msg_sect,
1127                                    u32 num_sect,
1128                                    u32 destaddr)
1129 {
1130         struct link *l_ptr;
1131         struct tipc_node *node;
1132         struct tipc_msg *hdr = &sender->phdr;
1133         u32 dsz = msg_data_sz(hdr);
1134         u32 max_pkt, fragm_sz, rest;
1135         struct tipc_msg fragm_hdr;
1136         struct sk_buff *buf, *buf_chain, *prev;
1137         u32 fragm_crs, fragm_rest, hsz, sect_rest;
1138         const unchar *sect_crs;
1139         int curr_sect;
1140         u32 fragm_no;
1141
1142 again:
1143         fragm_no = 1;
1144         max_pkt = sender->max_pkt - INT_H_SIZE;
1145                 /* leave room for tunnel header in case of link changeover */
1146         fragm_sz = max_pkt - INT_H_SIZE;
1147                 /* leave room for fragmentation header in each fragment */
1148         rest = dsz;
1149         fragm_crs = 0;
1150         fragm_rest = 0;
1151         sect_rest = 0;
1152         sect_crs = NULL;
1153         curr_sect = -1;
1154
1155         /* Prepare reusable fragment header: */
1156
1157         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
1158                  INT_H_SIZE, msg_destnode(hdr));
1159         msg_set_link_selector(&fragm_hdr, sender->ref);
1160         msg_set_size(&fragm_hdr, max_pkt);
1161         msg_set_fragm_no(&fragm_hdr, 1);
1162
1163         /* Prepare header of first fragment: */
1164
1165         buf_chain = buf = tipc_buf_acquire(max_pkt);
1166         if (!buf)
1167                 return -ENOMEM;
1168         buf->next = NULL;
1169         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1170         hsz = msg_hdr_sz(hdr);
1171         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, hdr, hsz);
1172
1173         /* Chop up message: */
1174
1175         fragm_crs = INT_H_SIZE + hsz;
1176         fragm_rest = fragm_sz - hsz;
1177
1178         do {            /* For all sections */
1179                 u32 sz;
1180
1181                 if (!sect_rest) {
1182                         sect_rest = msg_sect[++curr_sect].iov_len;
1183                         sect_crs = (const unchar *)msg_sect[curr_sect].iov_base;
1184                 }
1185
1186                 if (sect_rest < fragm_rest)
1187                         sz = sect_rest;
1188                 else
1189                         sz = fragm_rest;
1190
1191                 if (likely(!sender->user_port)) {
1192                         if (copy_from_user(buf->data + fragm_crs, sect_crs, sz)) {
1193 error:
1194                                 for (; buf_chain; buf_chain = buf) {
1195                                         buf = buf_chain->next;
1196                                         buf_discard(buf_chain);
1197                                 }
1198                                 return -EFAULT;
1199                         }
1200                 } else
1201                         skb_copy_to_linear_data_offset(buf, fragm_crs,
1202                                                        sect_crs, sz);
1203                 sect_crs += sz;
1204                 sect_rest -= sz;
1205                 fragm_crs += sz;
1206                 fragm_rest -= sz;
1207                 rest -= sz;
1208
1209                 if (!fragm_rest && rest) {
1210
1211                         /* Initiate new fragment: */
1212                         if (rest <= fragm_sz) {
1213                                 fragm_sz = rest;
1214                                 msg_set_type(&fragm_hdr, LAST_FRAGMENT);
1215                         } else {
1216                                 msg_set_type(&fragm_hdr, FRAGMENT);
1217                         }
1218                         msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
1219                         msg_set_fragm_no(&fragm_hdr, ++fragm_no);
1220                         prev = buf;
1221                         buf = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
1222                         if (!buf)
1223                                 goto error;
1224
1225                         buf->next = NULL;
1226                         prev->next = buf;
1227                         skb_copy_to_linear_data(buf, &fragm_hdr, INT_H_SIZE);
1228                         fragm_crs = INT_H_SIZE;
1229                         fragm_rest = fragm_sz;
1230                 }
1231         } while (rest > 0);
1232
1233         /*
1234          * Now we have a buffer chain. Select a link and check
1235          * that packet size is still OK
1236          */
1237         node = tipc_node_find(destaddr);
1238         if (likely(node)) {
1239                 tipc_node_lock(node);
1240                 l_ptr = node->active_links[sender->ref & 1];
1241                 if (!l_ptr) {
1242                         tipc_node_unlock(node);
1243                         goto reject;
1244                 }
1245                 if (l_ptr->max_pkt < max_pkt) {
1246                         sender->max_pkt = l_ptr->max_pkt;
1247                         tipc_node_unlock(node);
1248                         for (; buf_chain; buf_chain = buf) {
1249                                 buf = buf_chain->next;
1250                                 buf_discard(buf_chain);
1251                         }
1252                         goto again;
1253                 }
1254         } else {
1255 reject:
1256                 for (; buf_chain; buf_chain = buf) {
1257                         buf = buf_chain->next;
1258                         buf_discard(buf_chain);
1259                 }
1260                 return tipc_port_reject_sections(sender, hdr, msg_sect, num_sect,
1261                                                  TIPC_ERR_NO_NODE);
1262         }
1263
1264         /* Append whole chain to send queue: */
1265
1266         buf = buf_chain;
1267         l_ptr->long_msg_seq_no = mod(l_ptr->long_msg_seq_no + 1);
1268         if (!l_ptr->next_out)
1269                 l_ptr->next_out = buf_chain;
1270         l_ptr->stats.sent_fragmented++;
1271         while (buf) {
1272                 struct sk_buff *next = buf->next;
1273                 struct tipc_msg *msg = buf_msg(buf);
1274
1275                 l_ptr->stats.sent_fragments++;
1276                 msg_set_long_msgno(msg, l_ptr->long_msg_seq_no);
1277                 link_add_to_outqueue(l_ptr, buf, msg);
1278                 buf = next;
1279         }
1280
1281         /* Send it, if possible: */
1282
1283         tipc_link_push_queue(l_ptr);
1284         tipc_node_unlock(node);
1285         return dsz;
1286 }
1287
1288 /*
1289  * tipc_link_push_packet: Push one unsent packet to the media
1290  */
1291 u32 tipc_link_push_packet(struct link *l_ptr)
1292 {
1293         struct sk_buff *buf = l_ptr->first_out;
1294         u32 r_q_size = l_ptr->retransm_queue_size;
1295         u32 r_q_head = l_ptr->retransm_queue_head;
1296
1297         /* Step to position where retransmission failed, if any,    */
1298         /* consider that buffers may have been released in meantime */
1299
1300         if (r_q_size && buf) {
1301                 u32 last = lesser(mod(r_q_head + r_q_size),
1302                                   link_last_sent(l_ptr));
1303                 u32 first = msg_seqno(buf_msg(buf));
1304
1305                 while (buf && less(first, r_q_head)) {
1306                         first = mod(first + 1);
1307                         buf = buf->next;
1308                 }
1309                 l_ptr->retransm_queue_head = r_q_head = first;
1310                 l_ptr->retransm_queue_size = r_q_size = mod(last - first);
1311         }
1312
1313         /* Continue retransmission now, if there is anything: */
1314
1315         if (r_q_size && buf) {
1316                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1317                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1318                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1319                         l_ptr->retransm_queue_head = mod(++r_q_head);
1320                         l_ptr->retransm_queue_size = --r_q_size;
1321                         l_ptr->stats.retransmitted++;
1322                         return 0;
1323                 } else {
1324                         l_ptr->stats.bearer_congs++;
1325                         return PUSH_FAILED;
1326                 }
1327         }
1328
1329         /* Send deferred protocol message, if any: */
1330
1331         buf = l_ptr->proto_msg_queue;
1332         if (buf) {
1333                 msg_set_ack(buf_msg(buf), mod(l_ptr->next_in_no - 1));
1334                 msg_set_bcast_ack(buf_msg(buf), l_ptr->owner->bclink.last_in);
1335                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1336                         l_ptr->unacked_window = 0;
1337                         buf_discard(buf);
1338                         l_ptr->proto_msg_queue = NULL;
1339                         return 0;
1340                 } else {
1341                         l_ptr->stats.bearer_congs++;
1342                         return PUSH_FAILED;
1343                 }
1344         }
1345
1346         /* Send one deferred data message, if send window not full: */
1347
1348         buf = l_ptr->next_out;
1349         if (buf) {
1350                 struct tipc_msg *msg = buf_msg(buf);
1351                 u32 next = msg_seqno(msg);
1352                 u32 first = msg_seqno(buf_msg(l_ptr->first_out));
1353
1354                 if (mod(next - first) < l_ptr->queue_limit[0]) {
1355                         msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1356                         msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1357                         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1358                                 if (msg_user(msg) == MSG_BUNDLER)
1359                                         msg_set_type(msg, CLOSED_MSG);
1360                                 l_ptr->next_out = buf->next;
1361                                 return 0;
1362                         } else {
1363                                 l_ptr->stats.bearer_congs++;
1364                                 return PUSH_FAILED;
1365                         }
1366                 }
1367         }
1368         return PUSH_FINISHED;
1369 }
1370
1371 /*
1372  * push_queue(): push out the unsent messages of a link where
1373  *               congestion has abated. Node is locked
1374  */
1375 void tipc_link_push_queue(struct link *l_ptr)
1376 {
1377         u32 res;
1378
1379         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr))
1380                 return;
1381
1382         do {
1383                 res = tipc_link_push_packet(l_ptr);
1384         } while (!res);
1385
1386         if (res == PUSH_FAILED)
1387                 tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1388 }
1389
1390 static void link_reset_all(unsigned long addr)
1391 {
1392         struct tipc_node *n_ptr;
1393         char addr_string[16];
1394         u32 i;
1395
1396         read_lock_bh(&tipc_net_lock);
1397         n_ptr = tipc_node_find((u32)addr);
1398         if (!n_ptr) {
1399                 read_unlock_bh(&tipc_net_lock);
1400                 return; /* node no longer exists */
1401         }
1402
1403         tipc_node_lock(n_ptr);
1404
1405         warn("Resetting all links to %s\n",
1406              tipc_addr_string_fill(addr_string, n_ptr->addr));
1407
1408         for (i = 0; i < MAX_BEARERS; i++) {
1409                 if (n_ptr->links[i]) {
1410                         link_print(n_ptr->links[i], "Resetting link\n");
1411                         tipc_link_reset(n_ptr->links[i]);
1412                 }
1413         }
1414
1415         tipc_node_unlock(n_ptr);
1416         read_unlock_bh(&tipc_net_lock);
1417 }
1418
1419 static void link_retransmit_failure(struct link *l_ptr, struct sk_buff *buf)
1420 {
1421         struct tipc_msg *msg = buf_msg(buf);
1422
1423         warn("Retransmission failure on link <%s>\n", l_ptr->name);
1424
1425         if (l_ptr->addr) {
1426
1427                 /* Handle failure on standard link */
1428
1429                 link_print(l_ptr, "Resetting link\n");
1430                 tipc_link_reset(l_ptr);
1431
1432         } else {
1433
1434                 /* Handle failure on broadcast link */
1435
1436                 struct tipc_node *n_ptr;
1437                 char addr_string[16];
1438
1439                 info("Msg seq number: %u,  ", msg_seqno(msg));
1440                 info("Outstanding acks: %lu\n",
1441                      (unsigned long) TIPC_SKB_CB(buf)->handle);
1442
1443                 n_ptr = tipc_bclink_retransmit_to();
1444                 tipc_node_lock(n_ptr);
1445
1446                 tipc_addr_string_fill(addr_string, n_ptr->addr);
1447                 info("Multicast link info for %s\n", addr_string);
1448                 info("Supported: %d,  ", n_ptr->bclink.supported);
1449                 info("Acked: %u\n", n_ptr->bclink.acked);
1450                 info("Last in: %u,  ", n_ptr->bclink.last_in);
1451                 info("Gap after: %u,  ", n_ptr->bclink.gap_after);
1452                 info("Gap to: %u\n", n_ptr->bclink.gap_to);
1453                 info("Nack sync: %u\n\n", n_ptr->bclink.nack_sync);
1454
1455                 tipc_k_signal((Handler)link_reset_all, (unsigned long)n_ptr->addr);
1456
1457                 tipc_node_unlock(n_ptr);
1458
1459                 l_ptr->stale_count = 0;
1460         }
1461 }
1462
1463 void tipc_link_retransmit(struct link *l_ptr, struct sk_buff *buf,
1464                           u32 retransmits)
1465 {
1466         struct tipc_msg *msg;
1467
1468         if (!buf)
1469                 return;
1470
1471         msg = buf_msg(buf);
1472
1473         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
1474                 if (l_ptr->retransm_queue_size == 0) {
1475                         l_ptr->retransm_queue_head = msg_seqno(msg);
1476                         l_ptr->retransm_queue_size = retransmits;
1477                 } else {
1478                         err("Unexpected retransmit on link %s (qsize=%d)\n",
1479                             l_ptr->name, l_ptr->retransm_queue_size);
1480                 }
1481                 return;
1482         } else {
1483                 /* Detect repeated retransmit failures on uncongested bearer */
1484
1485                 if (l_ptr->last_retransmitted == msg_seqno(msg)) {
1486                         if (++l_ptr->stale_count > 100) {
1487                                 link_retransmit_failure(l_ptr, buf);
1488                                 return;
1489                         }
1490                 } else {
1491                         l_ptr->last_retransmitted = msg_seqno(msg);
1492                         l_ptr->stale_count = 1;
1493                 }
1494         }
1495
1496         while (retransmits && (buf != l_ptr->next_out) && buf) {
1497                 msg = buf_msg(buf);
1498                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1499                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
1500                 if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1501                         buf = buf->next;
1502                         retransmits--;
1503                         l_ptr->stats.retransmitted++;
1504                 } else {
1505                         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1506                         l_ptr->stats.bearer_congs++;
1507                         l_ptr->retransm_queue_head = msg_seqno(buf_msg(buf));
1508                         l_ptr->retransm_queue_size = retransmits;
1509                         return;
1510                 }
1511         }
1512
1513         l_ptr->retransm_queue_head = l_ptr->retransm_queue_size = 0;
1514 }
1515
1516 /**
1517  * link_insert_deferred_queue - insert deferred messages back into receive chain
1518  */
1519
1520 static struct sk_buff *link_insert_deferred_queue(struct link *l_ptr,
1521                                                   struct sk_buff *buf)
1522 {
1523         u32 seq_no;
1524
1525         if (l_ptr->oldest_deferred_in == NULL)
1526                 return buf;
1527
1528         seq_no = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
1529         if (seq_no == mod(l_ptr->next_in_no)) {
1530                 l_ptr->newest_deferred_in->next = buf;
1531                 buf = l_ptr->oldest_deferred_in;
1532                 l_ptr->oldest_deferred_in = NULL;
1533                 l_ptr->deferred_inqueue_sz = 0;
1534         }
1535         return buf;
1536 }
1537
1538 /**
1539  * link_recv_buf_validate - validate basic format of received message
1540  *
1541  * This routine ensures a TIPC message has an acceptable header, and at least
1542  * as much data as the header indicates it should.  The routine also ensures
1543  * that the entire message header is stored in the main fragment of the message
1544  * buffer, to simplify future access to message header fields.
1545  *
1546  * Note: Having extra info present in the message header or data areas is OK.
1547  * TIPC will ignore the excess, under the assumption that it is optional info
1548  * introduced by a later release of the protocol.
1549  */
1550
1551 static int link_recv_buf_validate(struct sk_buff *buf)
1552 {
1553         static u32 min_data_hdr_size[8] = {
1554                 SHORT_H_SIZE, MCAST_H_SIZE, LONG_H_SIZE, DIR_MSG_H_SIZE,
1555                 MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE, MAX_H_SIZE
1556                 };
1557
1558         struct tipc_msg *msg;
1559         u32 tipc_hdr[2];
1560         u32 size;
1561         u32 hdr_size;
1562         u32 min_hdr_size;
1563
1564         if (unlikely(buf->len < MIN_H_SIZE))
1565                 return 0;
1566
1567         msg = skb_header_pointer(buf, 0, sizeof(tipc_hdr), tipc_hdr);
1568         if (msg == NULL)
1569                 return 0;
1570
1571         if (unlikely(msg_version(msg) != TIPC_VERSION))
1572                 return 0;
1573
1574         size = msg_size(msg);
1575         hdr_size = msg_hdr_sz(msg);
1576         min_hdr_size = msg_isdata(msg) ?
1577                 min_data_hdr_size[msg_type(msg)] : INT_H_SIZE;
1578
1579         if (unlikely((hdr_size < min_hdr_size) ||
1580                      (size < hdr_size) ||
1581                      (buf->len < size) ||
1582                      (size - hdr_size > TIPC_MAX_USER_MSG_SIZE)))
1583                 return 0;
1584
1585         return pskb_may_pull(buf, hdr_size);
1586 }
1587
1588 /**
1589  * tipc_recv_msg - process TIPC messages arriving from off-node
1590  * @head: pointer to message buffer chain
1591  * @tb_ptr: pointer to bearer message arrived on
1592  *
1593  * Invoked with no locks held.  Bearer pointer must point to a valid bearer
1594  * structure (i.e. cannot be NULL), but bearer can be inactive.
1595  */
1596
1597 void tipc_recv_msg(struct sk_buff *head, struct tipc_bearer *b_ptr)
1598 {
1599         read_lock_bh(&tipc_net_lock);
1600         while (head) {
1601                 struct tipc_node *n_ptr;
1602                 struct link *l_ptr;
1603                 struct sk_buff *crs;
1604                 struct sk_buff *buf = head;
1605                 struct tipc_msg *msg;
1606                 u32 seq_no;
1607                 u32 ackd;
1608                 u32 released = 0;
1609                 int type;
1610
1611                 head = head->next;
1612
1613                 /* Ensure bearer is still enabled */
1614
1615                 if (unlikely(!b_ptr->active))
1616                         goto cont;
1617
1618                 /* Ensure message is well-formed */
1619
1620                 if (unlikely(!link_recv_buf_validate(buf)))
1621                         goto cont;
1622
1623                 /* Ensure message data is a single contiguous unit */
1624
1625                 if (unlikely(buf_linearize(buf)))
1626                         goto cont;
1627
1628                 /* Handle arrival of a non-unicast link message */
1629
1630                 msg = buf_msg(buf);
1631
1632                 if (unlikely(msg_non_seq(msg))) {
1633                         if (msg_user(msg) ==  LINK_CONFIG)
1634                                 tipc_disc_recv_msg(buf, b_ptr);
1635                         else
1636                                 tipc_bclink_recv_pkt(buf);
1637                         continue;
1638                 }
1639
1640                 if (unlikely(!msg_short(msg) &&
1641                              (msg_destnode(msg) != tipc_own_addr)))
1642                         goto cont;
1643
1644                 /* Discard non-routeable messages destined for another node */
1645
1646                 if (unlikely(!msg_isdata(msg) &&
1647                              (msg_destnode(msg) != tipc_own_addr))) {
1648                         if ((msg_user(msg) != CONN_MANAGER) &&
1649                             (msg_user(msg) != MSG_FRAGMENTER))
1650                                 goto cont;
1651                 }
1652
1653                 /* Locate neighboring node that sent message */
1654
1655                 n_ptr = tipc_node_find(msg_prevnode(msg));
1656                 if (unlikely(!n_ptr))
1657                         goto cont;
1658                 tipc_node_lock(n_ptr);
1659
1660                 /* Don't talk to neighbor during cleanup after last session */
1661
1662                 if (n_ptr->cleanup_required) {
1663                         tipc_node_unlock(n_ptr);
1664                         goto cont;
1665                 }
1666
1667                 /* Locate unicast link endpoint that should handle message */
1668
1669                 l_ptr = n_ptr->links[b_ptr->identity];
1670                 if (unlikely(!l_ptr)) {
1671                         tipc_node_unlock(n_ptr);
1672                         goto cont;
1673                 }
1674
1675                 /* Validate message sequence number info */
1676
1677                 seq_no = msg_seqno(msg);
1678                 ackd = msg_ack(msg);
1679
1680                 /* Release acked messages */
1681
1682                 if (less(n_ptr->bclink.acked, msg_bcast_ack(msg))) {
1683                         if (tipc_node_is_up(n_ptr) && n_ptr->bclink.supported)
1684                                 tipc_bclink_acknowledge(n_ptr, msg_bcast_ack(msg));
1685                 }
1686
1687                 crs = l_ptr->first_out;
1688                 while ((crs != l_ptr->next_out) &&
1689                        less_eq(msg_seqno(buf_msg(crs)), ackd)) {
1690                         struct sk_buff *next = crs->next;
1691
1692                         buf_discard(crs);
1693                         crs = next;
1694                         released++;
1695                 }
1696                 if (released) {
1697                         l_ptr->first_out = crs;
1698                         l_ptr->out_queue_size -= released;
1699                 }
1700
1701                 /* Try sending any messages link endpoint has pending */
1702
1703                 if (unlikely(l_ptr->next_out))
1704                         tipc_link_push_queue(l_ptr);
1705                 if (unlikely(!list_empty(&l_ptr->waiting_ports)))
1706                         tipc_link_wakeup_ports(l_ptr, 0);
1707                 if (unlikely(++l_ptr->unacked_window >= TIPC_MIN_LINK_WIN)) {
1708                         l_ptr->stats.sent_acks++;
1709                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1710                 }
1711
1712                 /* Now (finally!) process the incoming message */
1713
1714 protocol_check:
1715                 if (likely(link_working_working(l_ptr))) {
1716                         if (likely(seq_no == mod(l_ptr->next_in_no))) {
1717                                 l_ptr->next_in_no++;
1718                                 if (unlikely(l_ptr->oldest_deferred_in))
1719                                         head = link_insert_deferred_queue(l_ptr,
1720                                                                           head);
1721                                 if (likely(msg_is_dest(msg, tipc_own_addr))) {
1722 deliver:
1723                                         if (likely(msg_isdata(msg))) {
1724                                                 tipc_node_unlock(n_ptr);
1725                                                 tipc_port_recv_msg(buf);
1726                                                 continue;
1727                                         }
1728                                         switch (msg_user(msg)) {
1729                                         case MSG_BUNDLER:
1730                                                 l_ptr->stats.recv_bundles++;
1731                                                 l_ptr->stats.recv_bundled +=
1732                                                         msg_msgcnt(msg);
1733                                                 tipc_node_unlock(n_ptr);
1734                                                 tipc_link_recv_bundle(buf);
1735                                                 continue;
1736                                         case ROUTE_DISTRIBUTOR:
1737                                                 tipc_node_unlock(n_ptr);
1738                                                 buf_discard(buf);
1739                                                 continue;
1740                                         case NAME_DISTRIBUTOR:
1741                                                 tipc_node_unlock(n_ptr);
1742                                                 tipc_named_recv(buf);
1743                                                 continue;
1744                                         case CONN_MANAGER:
1745                                                 tipc_node_unlock(n_ptr);
1746                                                 tipc_port_recv_proto_msg(buf);
1747                                                 continue;
1748                                         case MSG_FRAGMENTER:
1749                                                 l_ptr->stats.recv_fragments++;
1750                                                 if (tipc_link_recv_fragment(&l_ptr->defragm_buf,
1751                                                                             &buf, &msg)) {
1752                                                         l_ptr->stats.recv_fragmented++;
1753                                                         goto deliver;
1754                                                 }
1755                                                 break;
1756                                         case CHANGEOVER_PROTOCOL:
1757                                                 type = msg_type(msg);
1758                                                 if (link_recv_changeover_msg(&l_ptr, &buf)) {
1759                                                         msg = buf_msg(buf);
1760                                                         seq_no = msg_seqno(msg);
1761                                                         if (type == ORIGINAL_MSG)
1762                                                                 goto deliver;
1763                                                         goto protocol_check;
1764                                                 }
1765                                                 break;
1766                                         }
1767                                 }
1768                                 tipc_node_unlock(n_ptr);
1769                                 tipc_net_route_msg(buf);
1770                                 continue;
1771                         }
1772                         link_handle_out_of_seq_msg(l_ptr, buf);
1773                         head = link_insert_deferred_queue(l_ptr, head);
1774                         tipc_node_unlock(n_ptr);
1775                         continue;
1776                 }
1777
1778                 if (msg_user(msg) == LINK_PROTOCOL) {
1779                         link_recv_proto_msg(l_ptr, buf);
1780                         head = link_insert_deferred_queue(l_ptr, head);
1781                         tipc_node_unlock(n_ptr);
1782                         continue;
1783                 }
1784                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
1785
1786                 if (link_working_working(l_ptr)) {
1787                         /* Re-insert in front of queue */
1788                         buf->next = head;
1789                         head = buf;
1790                         tipc_node_unlock(n_ptr);
1791                         continue;
1792                 }
1793                 tipc_node_unlock(n_ptr);
1794 cont:
1795                 buf_discard(buf);
1796         }
1797         read_unlock_bh(&tipc_net_lock);
1798 }
1799
1800 /*
1801  * link_defer_buf(): Sort a received out-of-sequence packet
1802  *                   into the deferred reception queue.
1803  * Returns the increase of the queue length,i.e. 0 or 1
1804  */
1805
1806 u32 tipc_link_defer_pkt(struct sk_buff **head,
1807                         struct sk_buff **tail,
1808                         struct sk_buff *buf)
1809 {
1810         struct sk_buff *prev = NULL;
1811         struct sk_buff *crs = *head;
1812         u32 seq_no = msg_seqno(buf_msg(buf));
1813
1814         buf->next = NULL;
1815
1816         /* Empty queue ? */
1817         if (*head == NULL) {
1818                 *head = *tail = buf;
1819                 return 1;
1820         }
1821
1822         /* Last ? */
1823         if (less(msg_seqno(buf_msg(*tail)), seq_no)) {
1824                 (*tail)->next = buf;
1825                 *tail = buf;
1826                 return 1;
1827         }
1828
1829         /* Scan through queue and sort it in */
1830         do {
1831                 struct tipc_msg *msg = buf_msg(crs);
1832
1833                 if (less(seq_no, msg_seqno(msg))) {
1834                         buf->next = crs;
1835                         if (prev)
1836                                 prev->next = buf;
1837                         else
1838                                 *head = buf;
1839                         return 1;
1840                 }
1841                 if (seq_no == msg_seqno(msg))
1842                         break;
1843                 prev = crs;
1844                 crs = crs->next;
1845         } while (crs);
1846
1847         /* Message is a duplicate of an existing message */
1848
1849         buf_discard(buf);
1850         return 0;
1851 }
1852
1853 /**
1854  * link_handle_out_of_seq_msg - handle arrival of out-of-sequence packet
1855  */
1856
1857 static void link_handle_out_of_seq_msg(struct link *l_ptr,
1858                                        struct sk_buff *buf)
1859 {
1860         u32 seq_no = msg_seqno(buf_msg(buf));
1861
1862         if (likely(msg_user(buf_msg(buf)) == LINK_PROTOCOL)) {
1863                 link_recv_proto_msg(l_ptr, buf);
1864                 return;
1865         }
1866
1867         /* Record OOS packet arrival (force mismatch on next timeout) */
1868
1869         l_ptr->checkpoint--;
1870
1871         /*
1872          * Discard packet if a duplicate; otherwise add it to deferred queue
1873          * and notify peer of gap as per protocol specification
1874          */
1875
1876         if (less(seq_no, mod(l_ptr->next_in_no))) {
1877                 l_ptr->stats.duplicates++;
1878                 buf_discard(buf);
1879                 return;
1880         }
1881
1882         if (tipc_link_defer_pkt(&l_ptr->oldest_deferred_in,
1883                                 &l_ptr->newest_deferred_in, buf)) {
1884                 l_ptr->deferred_inqueue_sz++;
1885                 l_ptr->stats.deferred_recv++;
1886                 if ((l_ptr->deferred_inqueue_sz % 16) == 1)
1887                         tipc_link_send_proto_msg(l_ptr, STATE_MSG, 0, 0, 0, 0, 0);
1888         } else
1889                 l_ptr->stats.duplicates++;
1890 }
1891
1892 /*
1893  * Send protocol message to the other endpoint.
1894  */
1895 void tipc_link_send_proto_msg(struct link *l_ptr, u32 msg_typ, int probe_msg,
1896                               u32 gap, u32 tolerance, u32 priority, u32 ack_mtu)
1897 {
1898         struct sk_buff *buf = NULL;
1899         struct tipc_msg *msg = l_ptr->pmsg;
1900         u32 msg_size = sizeof(l_ptr->proto_msg);
1901
1902         if (link_blocked(l_ptr))
1903                 return;
1904         msg_set_type(msg, msg_typ);
1905         msg_set_net_plane(msg, l_ptr->b_ptr->net_plane);
1906         msg_set_bcast_ack(msg, mod(l_ptr->owner->bclink.last_in));
1907         msg_set_last_bcast(msg, tipc_bclink_get_last_sent());
1908
1909         if (msg_typ == STATE_MSG) {
1910                 u32 next_sent = mod(l_ptr->next_out_no);
1911
1912                 if (!tipc_link_is_up(l_ptr))
1913                         return;
1914                 if (l_ptr->next_out)
1915                         next_sent = msg_seqno(buf_msg(l_ptr->next_out));
1916                 msg_set_next_sent(msg, next_sent);
1917                 if (l_ptr->oldest_deferred_in) {
1918                         u32 rec = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
1919                         gap = mod(rec - mod(l_ptr->next_in_no));
1920                 }
1921                 msg_set_seq_gap(msg, gap);
1922                 if (gap)
1923                         l_ptr->stats.sent_nacks++;
1924                 msg_set_link_tolerance(msg, tolerance);
1925                 msg_set_linkprio(msg, priority);
1926                 msg_set_max_pkt(msg, ack_mtu);
1927                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));
1928                 msg_set_probe(msg, probe_msg != 0);
1929                 if (probe_msg) {
1930                         u32 mtu = l_ptr->max_pkt;
1931
1932                         if ((mtu < l_ptr->max_pkt_target) &&
1933                             link_working_working(l_ptr) &&
1934                             l_ptr->fsm_msg_cnt) {
1935                                 msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1936                                 if (l_ptr->max_pkt_probes == 10) {
1937                                         l_ptr->max_pkt_target = (msg_size - 4);
1938                                         l_ptr->max_pkt_probes = 0;
1939                                         msg_size = (mtu + (l_ptr->max_pkt_target - mtu)/2 + 2) & ~3;
1940                                 }
1941                                 l_ptr->max_pkt_probes++;
1942                         }
1943
1944                         l_ptr->stats.sent_probes++;
1945                 }
1946                 l_ptr->stats.sent_states++;
1947         } else {                /* RESET_MSG or ACTIVATE_MSG */
1948                 msg_set_ack(msg, mod(l_ptr->reset_checkpoint - 1));
1949                 msg_set_seq_gap(msg, 0);
1950                 msg_set_next_sent(msg, 1);
1951                 msg_set_probe(msg, 0);
1952                 msg_set_link_tolerance(msg, l_ptr->tolerance);
1953                 msg_set_linkprio(msg, l_ptr->priority);
1954                 msg_set_max_pkt(msg, l_ptr->max_pkt_target);
1955         }
1956
1957         if (tipc_node_redundant_links(l_ptr->owner))
1958                 msg_set_redundant_link(msg);
1959         else
1960                 msg_clear_redundant_link(msg);
1961         msg_set_linkprio(msg, l_ptr->priority);
1962
1963         /* Ensure sequence number will not fit : */
1964
1965         msg_set_seqno(msg, mod(l_ptr->next_out_no + (0xffff/2)));
1966
1967         /* Congestion? */
1968
1969         if (tipc_bearer_congested(l_ptr->b_ptr, l_ptr)) {
1970                 if (!l_ptr->proto_msg_queue) {
1971                         l_ptr->proto_msg_queue =
1972                                 tipc_buf_acquire(sizeof(l_ptr->proto_msg));
1973                 }
1974                 buf = l_ptr->proto_msg_queue;
1975                 if (!buf)
1976                         return;
1977                 skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1978                 return;
1979         }
1980
1981         /* Message can be sent */
1982
1983         buf = tipc_buf_acquire(msg_size);
1984         if (!buf)
1985                 return;
1986
1987         skb_copy_to_linear_data(buf, msg, sizeof(l_ptr->proto_msg));
1988         msg_set_size(buf_msg(buf), msg_size);
1989
1990         if (tipc_bearer_send(l_ptr->b_ptr, buf, &l_ptr->media_addr)) {
1991                 l_ptr->unacked_window = 0;
1992                 buf_discard(buf);
1993                 return;
1994         }
1995
1996         /* New congestion */
1997         tipc_bearer_schedule(l_ptr->b_ptr, l_ptr);
1998         l_ptr->proto_msg_queue = buf;
1999         l_ptr->stats.bearer_congs++;
2000 }
2001
2002 /*
2003  * Receive protocol message :
2004  * Note that network plane id propagates through the network, and may
2005  * change at any time. The node with lowest address rules
2006  */
2007
2008 static void link_recv_proto_msg(struct link *l_ptr, struct sk_buff *buf)
2009 {
2010         u32 rec_gap = 0;
2011         u32 max_pkt_info;
2012         u32 max_pkt_ack;
2013         u32 msg_tol;
2014         struct tipc_msg *msg = buf_msg(buf);
2015
2016         if (link_blocked(l_ptr))
2017                 goto exit;
2018
2019         /* record unnumbered packet arrival (force mismatch on next timeout) */
2020
2021         l_ptr->checkpoint--;
2022
2023         if (l_ptr->b_ptr->net_plane != msg_net_plane(msg))
2024                 if (tipc_own_addr > msg_prevnode(msg))
2025                         l_ptr->b_ptr->net_plane = msg_net_plane(msg);
2026
2027         l_ptr->owner->permit_changeover = msg_redundant_link(msg);
2028
2029         switch (msg_type(msg)) {
2030
2031         case RESET_MSG:
2032                 if (!link_working_unknown(l_ptr) &&
2033                     (l_ptr->peer_session != INVALID_SESSION)) {
2034                         if (msg_session(msg) == l_ptr->peer_session)
2035                                 break; /* duplicate: ignore */
2036                 }
2037                 /* fall thru' */
2038         case ACTIVATE_MSG:
2039                 /* Update link settings according other endpoint's values */
2040
2041                 strcpy((strrchr(l_ptr->name, ':') + 1), (char *)msg_data(msg));
2042
2043                 msg_tol = msg_link_tolerance(msg);
2044                 if (msg_tol > l_ptr->tolerance)
2045                         link_set_supervision_props(l_ptr, msg_tol);
2046
2047                 if (msg_linkprio(msg) > l_ptr->priority)
2048                         l_ptr->priority = msg_linkprio(msg);
2049
2050                 max_pkt_info = msg_max_pkt(msg);
2051                 if (max_pkt_info) {
2052                         if (max_pkt_info < l_ptr->max_pkt_target)
2053                                 l_ptr->max_pkt_target = max_pkt_info;
2054                         if (l_ptr->max_pkt > l_ptr->max_pkt_target)
2055                                 l_ptr->max_pkt = l_ptr->max_pkt_target;
2056                 } else {
2057                         l_ptr->max_pkt = l_ptr->max_pkt_target;
2058                 }
2059                 l_ptr->owner->bclink.supported = (max_pkt_info != 0);
2060
2061                 link_state_event(l_ptr, msg_type(msg));
2062
2063                 l_ptr->peer_session = msg_session(msg);
2064                 l_ptr->peer_bearer_id = msg_bearer_id(msg);
2065
2066                 /* Synchronize broadcast sequence numbers */
2067                 if (!tipc_node_redundant_links(l_ptr->owner))
2068                         l_ptr->owner->bclink.last_in = mod(msg_last_bcast(msg));
2069                 break;
2070         case STATE_MSG:
2071
2072                 msg_tol = msg_link_tolerance(msg);
2073                 if (msg_tol)
2074                         link_set_supervision_props(l_ptr, msg_tol);
2075
2076                 if (msg_linkprio(msg) &&
2077                     (msg_linkprio(msg) != l_ptr->priority)) {
2078                         warn("Resetting link <%s>, priority change %u->%u\n",
2079                              l_ptr->name, l_ptr->priority, msg_linkprio(msg));
2080                         l_ptr->priority = msg_linkprio(msg);
2081                         tipc_link_reset(l_ptr); /* Enforce change to take effect */
2082                         break;
2083                 }
2084                 link_state_event(l_ptr, TRAFFIC_MSG_EVT);
2085                 l_ptr->stats.recv_states++;
2086                 if (link_reset_unknown(l_ptr))
2087                         break;
2088
2089                 if (less_eq(mod(l_ptr->next_in_no), msg_next_sent(msg))) {
2090                         rec_gap = mod(msg_next_sent(msg) -
2091                                       mod(l_ptr->next_in_no));
2092                 }
2093
2094                 max_pkt_ack = msg_max_pkt(msg);
2095                 if (max_pkt_ack > l_ptr->max_pkt) {
2096                         l_ptr->max_pkt = max_pkt_ack;
2097                         l_ptr->max_pkt_probes = 0;
2098                 }
2099
2100                 max_pkt_ack = 0;
2101                 if (msg_probe(msg)) {
2102                         l_ptr->stats.recv_probes++;
2103                         if (msg_size(msg) > sizeof(l_ptr->proto_msg))
2104                                 max_pkt_ack = msg_size(msg);
2105                 }
2106
2107                 /* Protocol message before retransmits, reduce loss risk */
2108
2109                 tipc_bclink_check_gap(l_ptr->owner, msg_last_bcast(msg));
2110
2111                 if (rec_gap || (msg_probe(msg))) {
2112                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2113                                                  0, rec_gap, 0, 0, max_pkt_ack);
2114                 }
2115                 if (msg_seq_gap(msg)) {
2116                         l_ptr->stats.recv_nacks++;
2117                         tipc_link_retransmit(l_ptr, l_ptr->first_out,
2118                                              msg_seq_gap(msg));
2119                 }
2120                 break;
2121         }
2122 exit:
2123         buf_discard(buf);
2124 }
2125
2126
2127 /*
2128  * tipc_link_tunnel(): Send one message via a link belonging to
2129  * another bearer. Owner node is locked.
2130  */
2131 static void tipc_link_tunnel(struct link *l_ptr,
2132                              struct tipc_msg *tunnel_hdr,
2133                              struct tipc_msg  *msg,
2134                              u32 selector)
2135 {
2136         struct link *tunnel;
2137         struct sk_buff *buf;
2138         u32 length = msg_size(msg);
2139
2140         tunnel = l_ptr->owner->active_links[selector & 1];
2141         if (!tipc_link_is_up(tunnel)) {
2142                 warn("Link changeover error, "
2143                      "tunnel link no longer available\n");
2144                 return;
2145         }
2146         msg_set_size(tunnel_hdr, length + INT_H_SIZE);
2147         buf = tipc_buf_acquire(length + INT_H_SIZE);
2148         if (!buf) {
2149                 warn("Link changeover error, "
2150                      "unable to send tunnel msg\n");
2151                 return;
2152         }
2153         skb_copy_to_linear_data(buf, tunnel_hdr, INT_H_SIZE);
2154         skb_copy_to_linear_data_offset(buf, INT_H_SIZE, msg, length);
2155         tipc_link_send_buf(tunnel, buf);
2156 }
2157
2158
2159
2160 /*
2161  * changeover(): Send whole message queue via the remaining link
2162  *               Owner node is locked.
2163  */
2164
2165 void tipc_link_changeover(struct link *l_ptr)
2166 {
2167         u32 msgcount = l_ptr->out_queue_size;
2168         struct sk_buff *crs = l_ptr->first_out;
2169         struct link *tunnel = l_ptr->owner->active_links[0];
2170         struct tipc_msg tunnel_hdr;
2171         int split_bundles;
2172
2173         if (!tunnel)
2174                 return;
2175
2176         if (!l_ptr->owner->permit_changeover) {
2177                 warn("Link changeover error, "
2178                      "peer did not permit changeover\n");
2179                 return;
2180         }
2181
2182         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2183                  ORIGINAL_MSG, INT_H_SIZE, l_ptr->addr);
2184         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2185         msg_set_msgcnt(&tunnel_hdr, msgcount);
2186
2187         if (!l_ptr->first_out) {
2188                 struct sk_buff *buf;
2189
2190                 buf = tipc_buf_acquire(INT_H_SIZE);
2191                 if (buf) {
2192                         skb_copy_to_linear_data(buf, &tunnel_hdr, INT_H_SIZE);
2193                         msg_set_size(&tunnel_hdr, INT_H_SIZE);
2194                         tipc_link_send_buf(tunnel, buf);
2195                 } else {
2196                         warn("Link changeover error, "
2197                              "unable to send changeover msg\n");
2198                 }
2199                 return;
2200         }
2201
2202         split_bundles = (l_ptr->owner->active_links[0] !=
2203                          l_ptr->owner->active_links[1]);
2204
2205         while (crs) {
2206                 struct tipc_msg *msg = buf_msg(crs);
2207
2208                 if ((msg_user(msg) == MSG_BUNDLER) && split_bundles) {
2209                         struct tipc_msg *m = msg_get_wrapped(msg);
2210                         unchar *pos = (unchar *)m;
2211
2212                         msgcount = msg_msgcnt(msg);
2213                         while (msgcount--) {
2214                                 msg_set_seqno(m, msg_seqno(msg));
2215                                 tipc_link_tunnel(l_ptr, &tunnel_hdr, m,
2216                                                  msg_link_selector(m));
2217                                 pos += align(msg_size(m));
2218                                 m = (struct tipc_msg *)pos;
2219                         }
2220                 } else {
2221                         tipc_link_tunnel(l_ptr, &tunnel_hdr, msg,
2222                                          msg_link_selector(msg));
2223                 }
2224                 crs = crs->next;
2225         }
2226 }
2227
2228 void tipc_link_send_duplicate(struct link *l_ptr, struct link *tunnel)
2229 {
2230         struct sk_buff *iter;
2231         struct tipc_msg tunnel_hdr;
2232
2233         tipc_msg_init(&tunnel_hdr, CHANGEOVER_PROTOCOL,
2234                  DUPLICATE_MSG, INT_H_SIZE, l_ptr->addr);
2235         msg_set_msgcnt(&tunnel_hdr, l_ptr->out_queue_size);
2236         msg_set_bearer_id(&tunnel_hdr, l_ptr->peer_bearer_id);
2237         iter = l_ptr->first_out;
2238         while (iter) {
2239                 struct sk_buff *outbuf;
2240                 struct tipc_msg *msg = buf_msg(iter);
2241                 u32 length = msg_size(msg);
2242
2243                 if (msg_user(msg) == MSG_BUNDLER)
2244                         msg_set_type(msg, CLOSED_MSG);
2245                 msg_set_ack(msg, mod(l_ptr->next_in_no - 1));   /* Update */
2246                 msg_set_bcast_ack(msg, l_ptr->owner->bclink.last_in);
2247                 msg_set_size(&tunnel_hdr, length + INT_H_SIZE);
2248                 outbuf = tipc_buf_acquire(length + INT_H_SIZE);
2249                 if (outbuf == NULL) {
2250                         warn("Link changeover error, "
2251                              "unable to send duplicate msg\n");
2252                         return;
2253                 }
2254                 skb_copy_to_linear_data(outbuf, &tunnel_hdr, INT_H_SIZE);
2255                 skb_copy_to_linear_data_offset(outbuf, INT_H_SIZE, iter->data,
2256                                                length);
2257                 tipc_link_send_buf(tunnel, outbuf);
2258                 if (!tipc_link_is_up(l_ptr))
2259                         return;
2260                 iter = iter->next;
2261         }
2262 }
2263
2264
2265
2266 /**
2267  * buf_extract - extracts embedded TIPC message from another message
2268  * @skb: encapsulating message buffer
2269  * @from_pos: offset to extract from
2270  *
2271  * Returns a new message buffer containing an embedded message.  The
2272  * encapsulating message itself is left unchanged.
2273  */
2274
2275 static struct sk_buff *buf_extract(struct sk_buff *skb, u32 from_pos)
2276 {
2277         struct tipc_msg *msg = (struct tipc_msg *)(skb->data + from_pos);
2278         u32 size = msg_size(msg);
2279         struct sk_buff *eb;
2280
2281         eb = tipc_buf_acquire(size);
2282         if (eb)
2283                 skb_copy_to_linear_data(eb, msg, size);
2284         return eb;
2285 }
2286
2287 /*
2288  *  link_recv_changeover_msg(): Receive tunneled packet sent
2289  *  via other link. Node is locked. Return extracted buffer.
2290  */
2291
2292 static int link_recv_changeover_msg(struct link **l_ptr,
2293                                     struct sk_buff **buf)
2294 {
2295         struct sk_buff *tunnel_buf = *buf;
2296         struct link *dest_link;
2297         struct tipc_msg *msg;
2298         struct tipc_msg *tunnel_msg = buf_msg(tunnel_buf);
2299         u32 msg_typ = msg_type(tunnel_msg);
2300         u32 msg_count = msg_msgcnt(tunnel_msg);
2301
2302         dest_link = (*l_ptr)->owner->links[msg_bearer_id(tunnel_msg)];
2303         if (!dest_link)
2304                 goto exit;
2305         if (dest_link == *l_ptr) {
2306                 err("Unexpected changeover message on link <%s>\n",
2307                     (*l_ptr)->name);
2308                 goto exit;
2309         }
2310         *l_ptr = dest_link;
2311         msg = msg_get_wrapped(tunnel_msg);
2312
2313         if (msg_typ == DUPLICATE_MSG) {
2314                 if (less(msg_seqno(msg), mod(dest_link->next_in_no)))
2315                         goto exit;
2316                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2317                 if (*buf == NULL) {
2318                         warn("Link changeover error, duplicate msg dropped\n");
2319                         goto exit;
2320                 }
2321                 buf_discard(tunnel_buf);
2322                 return 1;
2323         }
2324
2325         /* First original message ?: */
2326
2327         if (tipc_link_is_up(dest_link)) {
2328                 info("Resetting link <%s>, changeover initiated by peer\n",
2329                      dest_link->name);
2330                 tipc_link_reset(dest_link);
2331                 dest_link->exp_msg_count = msg_count;
2332                 if (!msg_count)
2333                         goto exit;
2334         } else if (dest_link->exp_msg_count == START_CHANGEOVER) {
2335                 dest_link->exp_msg_count = msg_count;
2336                 if (!msg_count)
2337                         goto exit;
2338         }
2339
2340         /* Receive original message */
2341
2342         if (dest_link->exp_msg_count == 0) {
2343                 warn("Link switchover error, "
2344                      "got too many tunnelled messages\n");
2345                 goto exit;
2346         }
2347         dest_link->exp_msg_count--;
2348         if (less(msg_seqno(msg), dest_link->reset_checkpoint)) {
2349                 goto exit;
2350         } else {
2351                 *buf = buf_extract(tunnel_buf, INT_H_SIZE);
2352                 if (*buf != NULL) {
2353                         buf_discard(tunnel_buf);
2354                         return 1;
2355                 } else {
2356                         warn("Link changeover error, original msg dropped\n");
2357                 }
2358         }
2359 exit:
2360         *buf = NULL;
2361         buf_discard(tunnel_buf);
2362         return 0;
2363 }
2364
2365 /*
2366  *  Bundler functionality:
2367  */
2368 void tipc_link_recv_bundle(struct sk_buff *buf)
2369 {
2370         u32 msgcount = msg_msgcnt(buf_msg(buf));
2371         u32 pos = INT_H_SIZE;
2372         struct sk_buff *obuf;
2373
2374         while (msgcount--) {
2375                 obuf = buf_extract(buf, pos);
2376                 if (obuf == NULL) {
2377                         warn("Link unable to unbundle message(s)\n");
2378                         break;
2379                 }
2380                 pos += align(msg_size(buf_msg(obuf)));
2381                 tipc_net_route_msg(obuf);
2382         }
2383         buf_discard(buf);
2384 }
2385
2386 /*
2387  *  Fragmentation/defragmentation:
2388  */
2389
2390
2391 /*
2392  * link_send_long_buf: Entry for buffers needing fragmentation.
2393  * The buffer is complete, inclusive total message length.
2394  * Returns user data length.
2395  */
2396 static int link_send_long_buf(struct link *l_ptr, struct sk_buff *buf)
2397 {
2398         struct tipc_msg *inmsg = buf_msg(buf);
2399         struct tipc_msg fragm_hdr;
2400         u32 insize = msg_size(inmsg);
2401         u32 dsz = msg_data_sz(inmsg);
2402         unchar *crs = buf->data;
2403         u32 rest = insize;
2404         u32 pack_sz = l_ptr->max_pkt;
2405         u32 fragm_sz = pack_sz - INT_H_SIZE;
2406         u32 fragm_no = 1;
2407         u32 destaddr;
2408
2409         if (msg_short(inmsg))
2410                 destaddr = l_ptr->addr;
2411         else
2412                 destaddr = msg_destnode(inmsg);
2413
2414         if (msg_routed(inmsg))
2415                 msg_set_prevnode(inmsg, tipc_own_addr);
2416
2417         /* Prepare reusable fragment header: */
2418
2419         tipc_msg_init(&fragm_hdr, MSG_FRAGMENTER, FIRST_FRAGMENT,
2420                  INT_H_SIZE, destaddr);
2421         msg_set_link_selector(&fragm_hdr, msg_link_selector(inmsg));
2422         msg_set_long_msgno(&fragm_hdr, mod(l_ptr->long_msg_seq_no++));
2423         msg_set_fragm_no(&fragm_hdr, fragm_no);
2424         l_ptr->stats.sent_fragmented++;
2425
2426         /* Chop up message: */
2427
2428         while (rest > 0) {
2429                 struct sk_buff *fragm;
2430
2431                 if (rest <= fragm_sz) {
2432                         fragm_sz = rest;
2433                         msg_set_type(&fragm_hdr, LAST_FRAGMENT);
2434                 }
2435                 fragm = tipc_buf_acquire(fragm_sz + INT_H_SIZE);
2436                 if (fragm == NULL) {
2437                         warn("Link unable to fragment message\n");
2438                         dsz = -ENOMEM;
2439                         goto exit;
2440                 }
2441                 msg_set_size(&fragm_hdr, fragm_sz + INT_H_SIZE);
2442                 skb_copy_to_linear_data(fragm, &fragm_hdr, INT_H_SIZE);
2443                 skb_copy_to_linear_data_offset(fragm, INT_H_SIZE, crs,
2444                                                fragm_sz);
2445                 /*  Send queued messages first, if any: */
2446
2447                 l_ptr->stats.sent_fragments++;
2448                 tipc_link_send_buf(l_ptr, fragm);
2449                 if (!tipc_link_is_up(l_ptr))
2450                         return dsz;
2451                 msg_set_fragm_no(&fragm_hdr, ++fragm_no);
2452                 rest -= fragm_sz;
2453                 crs += fragm_sz;
2454                 msg_set_type(&fragm_hdr, FRAGMENT);
2455         }
2456 exit:
2457         buf_discard(buf);
2458         return dsz;
2459 }
2460
2461 /*
2462  * A pending message being re-assembled must store certain values
2463  * to handle subsequent fragments correctly. The following functions
2464  * help storing these values in unused, available fields in the
2465  * pending message. This makes dynamic memory allocation unecessary.
2466  */
2467
2468 static void set_long_msg_seqno(struct sk_buff *buf, u32 seqno)
2469 {
2470         msg_set_seqno(buf_msg(buf), seqno);
2471 }
2472
2473 static u32 get_fragm_size(struct sk_buff *buf)
2474 {
2475         return msg_ack(buf_msg(buf));
2476 }
2477
2478 static void set_fragm_size(struct sk_buff *buf, u32 sz)
2479 {
2480         msg_set_ack(buf_msg(buf), sz);
2481 }
2482
2483 static u32 get_expected_frags(struct sk_buff *buf)
2484 {
2485         return msg_bcast_ack(buf_msg(buf));
2486 }
2487
2488 static void set_expected_frags(struct sk_buff *buf, u32 exp)
2489 {
2490         msg_set_bcast_ack(buf_msg(buf), exp);
2491 }
2492
2493 static u32 get_timer_cnt(struct sk_buff *buf)
2494 {
2495         return msg_reroute_cnt(buf_msg(buf));
2496 }
2497
2498 static void incr_timer_cnt(struct sk_buff *buf)
2499 {
2500         msg_incr_reroute_cnt(buf_msg(buf));
2501 }
2502
2503 /*
2504  * tipc_link_recv_fragment(): Called with node lock on. Returns
2505  * the reassembled buffer if message is complete.
2506  */
2507 int tipc_link_recv_fragment(struct sk_buff **pending, struct sk_buff **fb,
2508                             struct tipc_msg **m)
2509 {
2510         struct sk_buff *prev = NULL;
2511         struct sk_buff *fbuf = *fb;
2512         struct tipc_msg *fragm = buf_msg(fbuf);
2513         struct sk_buff *pbuf = *pending;
2514         u32 long_msg_seq_no = msg_long_msgno(fragm);
2515
2516         *fb = NULL;
2517
2518         /* Is there an incomplete message waiting for this fragment? */
2519
2520         while (pbuf && ((msg_seqno(buf_msg(pbuf)) != long_msg_seq_no) ||
2521                         (msg_orignode(fragm) != msg_orignode(buf_msg(pbuf))))) {
2522                 prev = pbuf;
2523                 pbuf = pbuf->next;
2524         }
2525
2526         if (!pbuf && (msg_type(fragm) == FIRST_FRAGMENT)) {
2527                 struct tipc_msg *imsg = (struct tipc_msg *)msg_data(fragm);
2528                 u32 msg_sz = msg_size(imsg);
2529                 u32 fragm_sz = msg_data_sz(fragm);
2530                 u32 exp_fragm_cnt = msg_sz/fragm_sz + !!(msg_sz % fragm_sz);
2531                 u32 max =  TIPC_MAX_USER_MSG_SIZE + LONG_H_SIZE;
2532                 if (msg_type(imsg) == TIPC_MCAST_MSG)
2533                         max = TIPC_MAX_USER_MSG_SIZE + MCAST_H_SIZE;
2534                 if (msg_size(imsg) > max) {
2535                         buf_discard(fbuf);
2536                         return 0;
2537                 }
2538                 pbuf = tipc_buf_acquire(msg_size(imsg));
2539                 if (pbuf != NULL) {
2540                         pbuf->next = *pending;
2541                         *pending = pbuf;
2542                         skb_copy_to_linear_data(pbuf, imsg,
2543                                                 msg_data_sz(fragm));
2544                         /*  Prepare buffer for subsequent fragments. */
2545
2546                         set_long_msg_seqno(pbuf, long_msg_seq_no);
2547                         set_fragm_size(pbuf, fragm_sz);
2548                         set_expected_frags(pbuf, exp_fragm_cnt - 1);
2549                 } else {
2550                         warn("Link unable to reassemble fragmented message\n");
2551                 }
2552                 buf_discard(fbuf);
2553                 return 0;
2554         } else if (pbuf && (msg_type(fragm) != FIRST_FRAGMENT)) {
2555                 u32 dsz = msg_data_sz(fragm);
2556                 u32 fsz = get_fragm_size(pbuf);
2557                 u32 crs = ((msg_fragm_no(fragm) - 1) * fsz);
2558                 u32 exp_frags = get_expected_frags(pbuf) - 1;
2559                 skb_copy_to_linear_data_offset(pbuf, crs,
2560                                                msg_data(fragm), dsz);
2561                 buf_discard(fbuf);
2562
2563                 /* Is message complete? */
2564
2565                 if (exp_frags == 0) {
2566                         if (prev)
2567                                 prev->next = pbuf->next;
2568                         else
2569                                 *pending = pbuf->next;
2570                         msg_reset_reroute_cnt(buf_msg(pbuf));
2571                         *fb = pbuf;
2572                         *m = buf_msg(pbuf);
2573                         return 1;
2574                 }
2575                 set_expected_frags(pbuf, exp_frags);
2576                 return 0;
2577         }
2578         buf_discard(fbuf);
2579         return 0;
2580 }
2581
2582 /**
2583  * link_check_defragm_bufs - flush stale incoming message fragments
2584  * @l_ptr: pointer to link
2585  */
2586
2587 static void link_check_defragm_bufs(struct link *l_ptr)
2588 {
2589         struct sk_buff *prev = NULL;
2590         struct sk_buff *next = NULL;
2591         struct sk_buff *buf = l_ptr->defragm_buf;
2592
2593         if (!buf)
2594                 return;
2595         if (!link_working_working(l_ptr))
2596                 return;
2597         while (buf) {
2598                 u32 cnt = get_timer_cnt(buf);
2599
2600                 next = buf->next;
2601                 if (cnt < 4) {
2602                         incr_timer_cnt(buf);
2603                         prev = buf;
2604                 } else {
2605                         if (prev)
2606                                 prev->next = buf->next;
2607                         else
2608                                 l_ptr->defragm_buf = buf->next;
2609                         buf_discard(buf);
2610                 }
2611                 buf = next;
2612         }
2613 }
2614
2615
2616
2617 static void link_set_supervision_props(struct link *l_ptr, u32 tolerance)
2618 {
2619         if ((tolerance < TIPC_MIN_LINK_TOL) || (tolerance > TIPC_MAX_LINK_TOL))
2620                 return;
2621
2622         l_ptr->tolerance = tolerance;
2623         l_ptr->continuity_interval =
2624                 ((tolerance / 4) > 500) ? 500 : tolerance / 4;
2625         l_ptr->abort_limit = tolerance / (l_ptr->continuity_interval / 4);
2626 }
2627
2628
2629 void tipc_link_set_queue_limits(struct link *l_ptr, u32 window)
2630 {
2631         /* Data messages from this node, inclusive FIRST_FRAGM */
2632         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE] = window;
2633         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE] = (window / 3) * 4;
2634         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE] = (window / 3) * 5;
2635         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE] = (window / 3) * 6;
2636         /* Transiting data messages,inclusive FIRST_FRAGM */
2637         l_ptr->queue_limit[TIPC_LOW_IMPORTANCE + 4] = 300;
2638         l_ptr->queue_limit[TIPC_MEDIUM_IMPORTANCE + 4] = 600;
2639         l_ptr->queue_limit[TIPC_HIGH_IMPORTANCE + 4] = 900;
2640         l_ptr->queue_limit[TIPC_CRITICAL_IMPORTANCE + 4] = 1200;
2641         l_ptr->queue_limit[CONN_MANAGER] = 1200;
2642         l_ptr->queue_limit[CHANGEOVER_PROTOCOL] = 2500;
2643         l_ptr->queue_limit[NAME_DISTRIBUTOR] = 3000;
2644         /* FRAGMENT and LAST_FRAGMENT packets */
2645         l_ptr->queue_limit[MSG_FRAGMENTER] = 4000;
2646 }
2647
2648 /**
2649  * link_find_link - locate link by name
2650  * @name - ptr to link name string
2651  * @node - ptr to area to be filled with ptr to associated node
2652  *
2653  * Caller must hold 'tipc_net_lock' to ensure node and bearer are not deleted;
2654  * this also prevents link deletion.
2655  *
2656  * Returns pointer to link (or 0 if invalid link name).
2657  */
2658
2659 static struct link *link_find_link(const char *name, struct tipc_node **node)
2660 {
2661         struct link_name link_name_parts;
2662         struct tipc_bearer *b_ptr;
2663         struct link *l_ptr;
2664
2665         if (!link_name_validate(name, &link_name_parts))
2666                 return NULL;
2667
2668         b_ptr = tipc_bearer_find_interface(link_name_parts.if_local);
2669         if (!b_ptr)
2670                 return NULL;
2671
2672         *node = tipc_node_find(link_name_parts.addr_peer);
2673         if (!*node)
2674                 return NULL;
2675
2676         l_ptr = (*node)->links[b_ptr->identity];
2677         if (!l_ptr || strcmp(l_ptr->name, name))
2678                 return NULL;
2679
2680         return l_ptr;
2681 }
2682
2683 struct sk_buff *tipc_link_cmd_config(const void *req_tlv_area, int req_tlv_space,
2684                                      u16 cmd)
2685 {
2686         struct tipc_link_config *args;
2687         u32 new_value;
2688         struct link *l_ptr;
2689         struct tipc_node *node;
2690         int res;
2691
2692         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_CONFIG))
2693                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2694
2695         args = (struct tipc_link_config *)TLV_DATA(req_tlv_area);
2696         new_value = ntohl(args->value);
2697
2698         if (!strcmp(args->name, tipc_bclink_name)) {
2699                 if ((cmd == TIPC_CMD_SET_LINK_WINDOW) &&
2700                     (tipc_bclink_set_queue_limits(new_value) == 0))
2701                         return tipc_cfg_reply_none();
2702                 return tipc_cfg_reply_error_string(TIPC_CFG_NOT_SUPPORTED
2703                                                    " (cannot change setting on broadcast link)");
2704         }
2705
2706         read_lock_bh(&tipc_net_lock);
2707         l_ptr = link_find_link(args->name, &node);
2708         if (!l_ptr) {
2709                 read_unlock_bh(&tipc_net_lock);
2710                 return tipc_cfg_reply_error_string("link not found");
2711         }
2712
2713         tipc_node_lock(node);
2714         res = -EINVAL;
2715         switch (cmd) {
2716         case TIPC_CMD_SET_LINK_TOL:
2717                 if ((new_value >= TIPC_MIN_LINK_TOL) &&
2718                     (new_value <= TIPC_MAX_LINK_TOL)) {
2719                         link_set_supervision_props(l_ptr, new_value);
2720                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2721                                                  0, 0, new_value, 0, 0);
2722                         res = 0;
2723                 }
2724                 break;
2725         case TIPC_CMD_SET_LINK_PRI:
2726                 if ((new_value >= TIPC_MIN_LINK_PRI) &&
2727                     (new_value <= TIPC_MAX_LINK_PRI)) {
2728                         l_ptr->priority = new_value;
2729                         tipc_link_send_proto_msg(l_ptr, STATE_MSG,
2730                                                  0, 0, 0, new_value, 0);
2731                         res = 0;
2732                 }
2733                 break;
2734         case TIPC_CMD_SET_LINK_WINDOW:
2735                 if ((new_value >= TIPC_MIN_LINK_WIN) &&
2736                     (new_value <= TIPC_MAX_LINK_WIN)) {
2737                         tipc_link_set_queue_limits(l_ptr, new_value);
2738                         res = 0;
2739                 }
2740                 break;
2741         }
2742         tipc_node_unlock(node);
2743
2744         read_unlock_bh(&tipc_net_lock);
2745         if (res)
2746                 return tipc_cfg_reply_error_string("cannot change link setting");
2747
2748         return tipc_cfg_reply_none();
2749 }
2750
2751 /**
2752  * link_reset_statistics - reset link statistics
2753  * @l_ptr: pointer to link
2754  */
2755
2756 static void link_reset_statistics(struct link *l_ptr)
2757 {
2758         memset(&l_ptr->stats, 0, sizeof(l_ptr->stats));
2759         l_ptr->stats.sent_info = l_ptr->next_out_no;
2760         l_ptr->stats.recv_info = l_ptr->next_in_no;
2761 }
2762
2763 struct sk_buff *tipc_link_cmd_reset_stats(const void *req_tlv_area, int req_tlv_space)
2764 {
2765         char *link_name;
2766         struct link *l_ptr;
2767         struct tipc_node *node;
2768
2769         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2770                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2771
2772         link_name = (char *)TLV_DATA(req_tlv_area);
2773         if (!strcmp(link_name, tipc_bclink_name)) {
2774                 if (tipc_bclink_reset_stats())
2775                         return tipc_cfg_reply_error_string("link not found");
2776                 return tipc_cfg_reply_none();
2777         }
2778
2779         read_lock_bh(&tipc_net_lock);
2780         l_ptr = link_find_link(link_name, &node);
2781         if (!l_ptr) {
2782                 read_unlock_bh(&tipc_net_lock);
2783                 return tipc_cfg_reply_error_string("link not found");
2784         }
2785
2786         tipc_node_lock(node);
2787         link_reset_statistics(l_ptr);
2788         tipc_node_unlock(node);
2789         read_unlock_bh(&tipc_net_lock);
2790         return tipc_cfg_reply_none();
2791 }
2792
2793 /**
2794  * percent - convert count to a percentage of total (rounding up or down)
2795  */
2796
2797 static u32 percent(u32 count, u32 total)
2798 {
2799         return (count * 100 + (total / 2)) / total;
2800 }
2801
2802 /**
2803  * tipc_link_stats - print link statistics
2804  * @name: link name
2805  * @buf: print buffer area
2806  * @buf_size: size of print buffer area
2807  *
2808  * Returns length of print buffer data string (or 0 if error)
2809  */
2810
2811 static int tipc_link_stats(const char *name, char *buf, const u32 buf_size)
2812 {
2813         struct print_buf pb;
2814         struct link *l_ptr;
2815         struct tipc_node *node;
2816         char *status;
2817         u32 profile_total = 0;
2818
2819         if (!strcmp(name, tipc_bclink_name))
2820                 return tipc_bclink_stats(buf, buf_size);
2821
2822         tipc_printbuf_init(&pb, buf, buf_size);
2823
2824         read_lock_bh(&tipc_net_lock);
2825         l_ptr = link_find_link(name, &node);
2826         if (!l_ptr) {
2827                 read_unlock_bh(&tipc_net_lock);
2828                 return 0;
2829         }
2830         tipc_node_lock(node);
2831
2832         if (tipc_link_is_active(l_ptr))
2833                 status = "ACTIVE";
2834         else if (tipc_link_is_up(l_ptr))
2835                 status = "STANDBY";
2836         else
2837                 status = "DEFUNCT";
2838         tipc_printf(&pb, "Link <%s>\n"
2839                          "  %s  MTU:%u  Priority:%u  Tolerance:%u ms"
2840                          "  Window:%u packets\n",
2841                     l_ptr->name, status, l_ptr->max_pkt,
2842                     l_ptr->priority, l_ptr->tolerance, l_ptr->queue_limit[0]);
2843         tipc_printf(&pb, "  RX packets:%u fragments:%u/%u bundles:%u/%u\n",
2844                     l_ptr->next_in_no - l_ptr->stats.recv_info,
2845                     l_ptr->stats.recv_fragments,
2846                     l_ptr->stats.recv_fragmented,
2847                     l_ptr->stats.recv_bundles,
2848                     l_ptr->stats.recv_bundled);
2849         tipc_printf(&pb, "  TX packets:%u fragments:%u/%u bundles:%u/%u\n",
2850                     l_ptr->next_out_no - l_ptr->stats.sent_info,
2851                     l_ptr->stats.sent_fragments,
2852                     l_ptr->stats.sent_fragmented,
2853                     l_ptr->stats.sent_bundles,
2854                     l_ptr->stats.sent_bundled);
2855         profile_total = l_ptr->stats.msg_length_counts;
2856         if (!profile_total)
2857                 profile_total = 1;
2858         tipc_printf(&pb, "  TX profile sample:%u packets  average:%u octets\n"
2859                          "  0-64:%u%% -256:%u%% -1024:%u%% -4096:%u%% "
2860                          "-16354:%u%% -32768:%u%% -66000:%u%%\n",
2861                     l_ptr->stats.msg_length_counts,
2862                     l_ptr->stats.msg_lengths_total / profile_total,
2863                     percent(l_ptr->stats.msg_length_profile[0], profile_total),
2864                     percent(l_ptr->stats.msg_length_profile[1], profile_total),
2865                     percent(l_ptr->stats.msg_length_profile[2], profile_total),
2866                     percent(l_ptr->stats.msg_length_profile[3], profile_total),
2867                     percent(l_ptr->stats.msg_length_profile[4], profile_total),
2868                     percent(l_ptr->stats.msg_length_profile[5], profile_total),
2869                     percent(l_ptr->stats.msg_length_profile[6], profile_total));
2870         tipc_printf(&pb, "  RX states:%u probes:%u naks:%u defs:%u dups:%u\n",
2871                     l_ptr->stats.recv_states,
2872                     l_ptr->stats.recv_probes,
2873                     l_ptr->stats.recv_nacks,
2874                     l_ptr->stats.deferred_recv,
2875                     l_ptr->stats.duplicates);
2876         tipc_printf(&pb, "  TX states:%u probes:%u naks:%u acks:%u dups:%u\n",
2877                     l_ptr->stats.sent_states,
2878                     l_ptr->stats.sent_probes,
2879                     l_ptr->stats.sent_nacks,
2880                     l_ptr->stats.sent_acks,
2881                     l_ptr->stats.retransmitted);
2882         tipc_printf(&pb, "  Congestion bearer:%u link:%u  Send queue max:%u avg:%u\n",
2883                     l_ptr->stats.bearer_congs,
2884                     l_ptr->stats.link_congs,
2885                     l_ptr->stats.max_queue_sz,
2886                     l_ptr->stats.queue_sz_counts
2887                     ? (l_ptr->stats.accu_queue_sz / l_ptr->stats.queue_sz_counts)
2888                     : 0);
2889
2890         tipc_node_unlock(node);
2891         read_unlock_bh(&tipc_net_lock);
2892         return tipc_printbuf_validate(&pb);
2893 }
2894
2895 #define MAX_LINK_STATS_INFO 2000
2896
2897 struct sk_buff *tipc_link_cmd_show_stats(const void *req_tlv_area, int req_tlv_space)
2898 {
2899         struct sk_buff *buf;
2900         struct tlv_desc *rep_tlv;
2901         int str_len;
2902
2903         if (!TLV_CHECK(req_tlv_area, req_tlv_space, TIPC_TLV_LINK_NAME))
2904                 return tipc_cfg_reply_error_string(TIPC_CFG_TLV_ERROR);
2905
2906         buf = tipc_cfg_reply_alloc(TLV_SPACE(MAX_LINK_STATS_INFO));
2907         if (!buf)
2908                 return NULL;
2909
2910         rep_tlv = (struct tlv_desc *)buf->data;
2911
2912         str_len = tipc_link_stats((char *)TLV_DATA(req_tlv_area),
2913                                   (char *)TLV_DATA(rep_tlv), MAX_LINK_STATS_INFO);
2914         if (!str_len) {
2915                 buf_discard(buf);
2916                 return tipc_cfg_reply_error_string("link not found");
2917         }
2918
2919         skb_put(buf, TLV_SPACE(str_len));
2920         TLV_SET(rep_tlv, TIPC_TLV_ULTRA_STRING, NULL, str_len);
2921
2922         return buf;
2923 }
2924
2925 /**
2926  * tipc_link_get_max_pkt - get maximum packet size to use when sending to destination
2927  * @dest: network address of destination node
2928  * @selector: used to select from set of active links
2929  *
2930  * If no active link can be found, uses default maximum packet size.
2931  */
2932
2933 u32 tipc_link_get_max_pkt(u32 dest, u32 selector)
2934 {
2935         struct tipc_node *n_ptr;
2936         struct link *l_ptr;
2937         u32 res = MAX_PKT_DEFAULT;
2938
2939         if (dest == tipc_own_addr)
2940                 return MAX_MSG_SIZE;
2941
2942         read_lock_bh(&tipc_net_lock);
2943         n_ptr = tipc_node_find(dest);
2944         if (n_ptr) {
2945                 tipc_node_lock(n_ptr);
2946                 l_ptr = n_ptr->active_links[selector & 1];
2947                 if (l_ptr)
2948                         res = l_ptr->max_pkt;
2949                 tipc_node_unlock(n_ptr);
2950         }
2951         read_unlock_bh(&tipc_net_lock);
2952         return res;
2953 }
2954
2955 static void link_print(struct link *l_ptr, const char *str)
2956 {
2957         char print_area[256];
2958         struct print_buf pb;
2959         struct print_buf *buf = &pb;
2960
2961         tipc_printbuf_init(buf, print_area, sizeof(print_area));
2962
2963         tipc_printf(buf, str);
2964         tipc_printf(buf, "Link %x<%s>:",
2965                     l_ptr->addr, l_ptr->b_ptr->name);
2966
2967 #ifdef CONFIG_TIPC_DEBUG
2968         if (link_reset_reset(l_ptr) || link_reset_unknown(l_ptr))
2969                 goto print_state;
2970
2971         tipc_printf(buf, ": NXO(%u):", mod(l_ptr->next_out_no));
2972         tipc_printf(buf, "NXI(%u):", mod(l_ptr->next_in_no));
2973         tipc_printf(buf, "SQUE");
2974         if (l_ptr->first_out) {
2975                 tipc_printf(buf, "[%u..", msg_seqno(buf_msg(l_ptr->first_out)));
2976                 if (l_ptr->next_out)
2977                         tipc_printf(buf, "%u..",
2978                                     msg_seqno(buf_msg(l_ptr->next_out)));
2979                 tipc_printf(buf, "%u]", msg_seqno(buf_msg(l_ptr->last_out)));
2980                 if ((mod(msg_seqno(buf_msg(l_ptr->last_out)) -
2981                          msg_seqno(buf_msg(l_ptr->first_out)))
2982                      != (l_ptr->out_queue_size - 1)) ||
2983                     (l_ptr->last_out->next != NULL)) {
2984                         tipc_printf(buf, "\nSend queue inconsistency\n");
2985                         tipc_printf(buf, "first_out= %p ", l_ptr->first_out);
2986                         tipc_printf(buf, "next_out= %p ", l_ptr->next_out);
2987                         tipc_printf(buf, "last_out= %p ", l_ptr->last_out);
2988                 }
2989         } else
2990                 tipc_printf(buf, "[]");
2991         tipc_printf(buf, "SQSIZ(%u)", l_ptr->out_queue_size);
2992         if (l_ptr->oldest_deferred_in) {
2993                 u32 o = msg_seqno(buf_msg(l_ptr->oldest_deferred_in));
2994                 u32 n = msg_seqno(buf_msg(l_ptr->newest_deferred_in));
2995                 tipc_printf(buf, ":RQUE[%u..%u]", o, n);
2996                 if (l_ptr->deferred_inqueue_sz != mod((n + 1) - o)) {
2997                         tipc_printf(buf, ":RQSIZ(%u)",
2998                                     l_ptr->deferred_inqueue_sz);
2999                 }
3000         }
3001 print_state:
3002 #endif
3003
3004         if (link_working_unknown(l_ptr))
3005                 tipc_printf(buf, ":WU");
3006         else if (link_reset_reset(l_ptr))
3007                 tipc_printf(buf, ":RR");
3008         else if (link_reset_unknown(l_ptr))
3009                 tipc_printf(buf, ":RU");
3010         else if (link_working_working(l_ptr))
3011                 tipc_printf(buf, ":WW");
3012         tipc_printf(buf, "\n");
3013
3014         tipc_printbuf_validate(buf);
3015         info("%s", print_area);
3016 }
3017