1/*
  2 * net/tipc/bearer.c: TIPC bearer code
  3 *
  4 * Copyright (c) 1996-2006, Ericsson AB
  5 * Copyright (c) 2004-2006, 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 "config.h"
 39#include "bearer.h"
 40#include "discover.h"
 41
 42#define MAX_ADDR_STR 32
 43
 44static struct tipc_media *media_list[MAX_MEDIA];
 45static u32 media_count;
 46
 47struct tipc_bearer tipc_bearers[MAX_BEARERS];
 48
 49static void bearer_disable(struct tipc_bearer *b_ptr);
 50
 51/**
 52 * media_name_valid - validate media name
 53 *
 54 * Returns 1 if media name is valid, otherwise 0.
 55 */
 56static int media_name_valid(const char *name)
 57{
 58	u32 len;
 59
 60	len = strlen(name);
 61	if ((len + 1) > TIPC_MAX_MEDIA_NAME)
 62		return 0;
 63	return strspn(name, tipc_alphabet) == len;
 64}
 65
 66/**
 67 * tipc_media_find - locates specified media object by name
 68 */
 69struct tipc_media *tipc_media_find(const char *name)
 70{
 71	u32 i;
 72
 73	for (i = 0; i < media_count; i++) {
 74		if (!strcmp(media_list[i]->name, name))
 75			return media_list[i];
 76	}
 77	return NULL;
 78}
 79
 80/**
 81 * media_find_id - locates specified media object by type identifier
 82 */
 83static struct tipc_media *media_find_id(u8 type)
 84{
 85	u32 i;
 86
 87	for (i = 0; i < media_count; i++) {
 88		if (media_list[i]->type_id == type)
 89			return media_list[i];
 90	}
 91	return NULL;
 92}
 93
 94/**
 95 * tipc_register_media - register a media type
 96 *
 97 * Bearers for this media type must be activated separately at a later stage.
 98 */
 99int tipc_register_media(struct tipc_media *m_ptr)
100{
101	int res = -EINVAL;
102
103	write_lock_bh(&tipc_net_lock);
104
105	if (!media_name_valid(m_ptr->name))
106		goto exit;
107	if ((m_ptr->bcast_addr.media_id != m_ptr->type_id) ||
108	    !m_ptr->bcast_addr.broadcast)
109		goto exit;
110	if (m_ptr->priority > TIPC_MAX_LINK_PRI)
111		goto exit;
112	if ((m_ptr->tolerance < TIPC_MIN_LINK_TOL) ||
113	    (m_ptr->tolerance > TIPC_MAX_LINK_TOL))
114		goto exit;
115	if (media_count >= MAX_MEDIA)
116		goto exit;
117	if (tipc_media_find(m_ptr->name) || media_find_id(m_ptr->type_id))
118		goto exit;
119
120	media_list[media_count] = m_ptr;
121	media_count++;
122	res = 0;
123exit:
124	write_unlock_bh(&tipc_net_lock);
125	if (res)
126		warn("Media <%s> registration error\n", m_ptr->name);
127	return res;
128}
129
130/**
131 * tipc_media_addr_printf - record media address in print buffer
132 */
133void tipc_media_addr_printf(struct print_buf *pb, struct tipc_media_addr *a)
134{
135	char addr_str[MAX_ADDR_STR];
136	struct tipc_media *m_ptr;
137
138	m_ptr = media_find_id(a->media_id);
139
140	if (m_ptr && !m_ptr->addr2str(a, addr_str, sizeof(addr_str)))
141		tipc_printf(pb, "%s(%s)", m_ptr->name, addr_str);
142	else {
143		u32 i;
144
145		tipc_printf(pb, "UNKNOWN(%u)", a->media_id);
146		for (i = 0; i < sizeof(a->value); i++)
147			tipc_printf(pb, "-%02x", a->value[i]);
148	}
149}
150
151/**
152 * tipc_media_get_names - record names of registered media in buffer
153 */
154struct sk_buff *tipc_media_get_names(void)
155{
156	struct sk_buff *buf;
157	int i;
158
159	buf = tipc_cfg_reply_alloc(MAX_MEDIA * TLV_SPACE(TIPC_MAX_MEDIA_NAME));
160	if (!buf)
161		return NULL;
162
163	read_lock_bh(&tipc_net_lock);
164	for (i = 0; i < media_count; i++) {
165		tipc_cfg_append_tlv(buf, TIPC_TLV_MEDIA_NAME,
166				    media_list[i]->name,
167				    strlen(media_list[i]->name) + 1);
168	}
169	read_unlock_bh(&tipc_net_lock);
170	return buf;
171}
172
173/**
174 * bearer_name_validate - validate & (optionally) deconstruct bearer name
175 * @name - ptr to bearer name string
176 * @name_parts - ptr to area for bearer name components (or NULL if not needed)
177 *
178 * Returns 1 if bearer name is valid, otherwise 0.
179 */
180static int bearer_name_validate(const char *name,
181				struct tipc_bearer_names *name_parts)
182{
183	char name_copy[TIPC_MAX_BEARER_NAME];
184	char *media_name;
185	char *if_name;
186	u32 media_len;
187	u32 if_len;
188
189	/* copy bearer name & ensure length is OK */
190	name_copy[TIPC_MAX_BEARER_NAME - 1] = 0;
191	/* need above in case non-Posix strncpy() doesn't pad with nulls */
192	strncpy(name_copy, name, TIPC_MAX_BEARER_NAME);
193	if (name_copy[TIPC_MAX_BEARER_NAME - 1] != 0)
194		return 0;
195
196	/* ensure all component parts of bearer name are present */
197	media_name = name_copy;
198	if_name = strchr(media_name, ':');
199	if (if_name == NULL)
200		return 0;
201	*(if_name++) = 0;
202	media_len = if_name - media_name;
203	if_len = strlen(if_name) + 1;
204
205	/* validate component parts of bearer name */
206	if ((media_len <= 1) || (media_len > TIPC_MAX_MEDIA_NAME) ||
207	    (if_len <= 1) || (if_len > TIPC_MAX_IF_NAME) ||
208	    (strspn(media_name, tipc_alphabet) != (media_len - 1)) ||
209	    (strspn(if_name, tipc_alphabet) != (if_len - 1)))
210		return 0;
211
212	/* return bearer name components, if necessary */
213	if (name_parts) {
214		strcpy(name_parts->media_name, media_name);
215		strcpy(name_parts->if_name, if_name);
216	}
217	return 1;
218}
219
220/**
221 * tipc_bearer_find - locates bearer object with matching bearer name
222 */
223struct tipc_bearer *tipc_bearer_find(const char *name)
224{
225	struct tipc_bearer *b_ptr;
226	u32 i;
227
228	for (i = 0, b_ptr = tipc_bearers; i < MAX_BEARERS; i++, b_ptr++) {
229		if (b_ptr->active && (!strcmp(b_ptr->name, name)))
230			return b_ptr;
231	}
232	return NULL;
233}
234
235/**
236 * tipc_bearer_find_interface - locates bearer object with matching interface name
237 */
238struct tipc_bearer *tipc_bearer_find_interface(const char *if_name)
239{
240	struct tipc_bearer *b_ptr;
241	char *b_if_name;
242	u32 i;
243
244	for (i = 0, b_ptr = tipc_bearers; i < MAX_BEARERS; i++, b_ptr++) {
245		if (!b_ptr->active)
246			continue;
247		b_if_name = strchr(b_ptr->name, ':') + 1;
248		if (!strcmp(b_if_name, if_name))
249			return b_ptr;
250	}
251	return NULL;
252}
253
254/**
255 * tipc_bearer_get_names - record names of bearers in buffer
256 */
257struct sk_buff *tipc_bearer_get_names(void)
258{
259	struct sk_buff *buf;
260	struct tipc_bearer *b_ptr;
261	int i, j;
262
263	buf = tipc_cfg_reply_alloc(MAX_BEARERS * TLV_SPACE(TIPC_MAX_BEARER_NAME));
264	if (!buf)
265		return NULL;
266
267	read_lock_bh(&tipc_net_lock);
268	for (i = 0; i < media_count; i++) {
269		for (j = 0; j < MAX_BEARERS; j++) {
270			b_ptr = &tipc_bearers[j];
271			if (b_ptr->active && (b_ptr->media == media_list[i])) {
272				tipc_cfg_append_tlv(buf, TIPC_TLV_BEARER_NAME,
273						    b_ptr->name,
274						    strlen(b_ptr->name) + 1);
275			}
276		}
277	}
278	read_unlock_bh(&tipc_net_lock);
279	return buf;
280}
281
282void tipc_bearer_add_dest(struct tipc_bearer *b_ptr, u32 dest)
283{
284	tipc_nmap_add(&b_ptr->nodes, dest);
285	tipc_bcbearer_sort();
286	tipc_disc_add_dest(b_ptr->link_req);
287}
288
289void tipc_bearer_remove_dest(struct tipc_bearer *b_ptr, u32 dest)
290{
291	tipc_nmap_remove(&b_ptr->nodes, dest);
292	tipc_bcbearer_sort();
293	tipc_disc_remove_dest(b_ptr->link_req);
294}
295
296/*
297 * bearer_push(): Resolve bearer congestion. Force the waiting
298 * links to push out their unsent packets, one packet per link
299 * per iteration, until all packets are gone or congestion reoccurs.
300 * 'tipc_net_lock' is read_locked when this function is called
301 * bearer.lock must be taken before calling
302 * Returns binary true(1) ore false(0)
303 */
304static int bearer_push(struct tipc_bearer *b_ptr)
305{
306	u32 res = 0;
307	struct tipc_link *ln, *tln;
308
309	if (b_ptr->blocked)
310		return 0;
311
312	while (!list_empty(&b_ptr->cong_links) && (res != PUSH_FAILED)) {
313		list_for_each_entry_safe(ln, tln, &b_ptr->cong_links, link_list) {
314			res = tipc_link_push_packet(ln);
315			if (res == PUSH_FAILED)
316				break;
317			if (res == PUSH_FINISHED)
318				list_move_tail(&ln->link_list, &b_ptr->links);
319		}
320	}
321	return list_empty(&b_ptr->cong_links);
322}
323
324void tipc_bearer_lock_push(struct tipc_bearer *b_ptr)
325{
326	spin_lock_bh(&b_ptr->lock);
327	bearer_push(b_ptr);
328	spin_unlock_bh(&b_ptr->lock);
329}
330
331
332/*
333 * Interrupt enabling new requests after bearer congestion or blocking:
334 * See bearer_send().
335 */
336void tipc_continue(struct tipc_bearer *b_ptr)
337{
338	spin_lock_bh(&b_ptr->lock);
339	if (!list_empty(&b_ptr->cong_links))
340		tipc_k_signal((Handler)tipc_bearer_lock_push, (unsigned long)b_ptr);
341	b_ptr->blocked = 0;
342	spin_unlock_bh(&b_ptr->lock);
343}
344
345/*
346 * Schedule link for sending of messages after the bearer
347 * has been deblocked by 'continue()'. This method is called
348 * when somebody tries to send a message via this link while
349 * the bearer is congested. 'tipc_net_lock' is in read_lock here
350 * bearer.lock is busy
351 */
352static void tipc_bearer_schedule_unlocked(struct tipc_bearer *b_ptr,
353						struct tipc_link *l_ptr)
354{
355	list_move_tail(&l_ptr->link_list, &b_ptr->cong_links);
356}
357
358/*
359 * Schedule link for sending of messages after the bearer
360 * has been deblocked by 'continue()'. This method is called
361 * when somebody tries to send a message via this link while
362 * the bearer is congested. 'tipc_net_lock' is in read_lock here,
363 * bearer.lock is free
364 */
365void tipc_bearer_schedule(struct tipc_bearer *b_ptr, struct tipc_link *l_ptr)
366{
367	spin_lock_bh(&b_ptr->lock);
368	tipc_bearer_schedule_unlocked(b_ptr, l_ptr);
369	spin_unlock_bh(&b_ptr->lock);
370}
371
372
373/*
374 * tipc_bearer_resolve_congestion(): Check if there is bearer congestion,
375 * and if there is, try to resolve it before returning.
376 * 'tipc_net_lock' is read_locked when this function is called
377 */
378int tipc_bearer_resolve_congestion(struct tipc_bearer *b_ptr,
379					struct tipc_link *l_ptr)
380{
381	int res = 1;
382
383	if (list_empty(&b_ptr->cong_links))
384		return 1;
385	spin_lock_bh(&b_ptr->lock);
386	if (!bearer_push(b_ptr)) {
387		tipc_bearer_schedule_unlocked(b_ptr, l_ptr);
388		res = 0;
389	}
390	spin_unlock_bh(&b_ptr->lock);
391	return res;
392}
393
394/**
395 * tipc_bearer_congested - determines if bearer is currently congested
396 */
397int tipc_bearer_congested(struct tipc_bearer *b_ptr, struct tipc_link *l_ptr)
398{
399	if (unlikely(b_ptr->blocked))
400		return 1;
401	if (likely(list_empty(&b_ptr->cong_links)))
402		return 0;
403	return !tipc_bearer_resolve_congestion(b_ptr, l_ptr);
404}
405
406/**
407 * tipc_enable_bearer - enable bearer with the given name
408 */
409int tipc_enable_bearer(const char *name, u32 disc_domain, u32 priority)
410{
411	struct tipc_bearer *b_ptr;
412	struct tipc_media *m_ptr;
413	struct tipc_bearer_names b_names;
414	char addr_string[16];
415	u32 bearer_id;
416	u32 with_this_prio;
417	u32 i;
418	int res = -EINVAL;
419
420	if (!tipc_own_addr) {
421		warn("Bearer <%s> rejected, not supported in standalone mode\n",
422		     name);
423		return -ENOPROTOOPT;
424	}
425	if (!bearer_name_validate(name, &b_names)) {
426		warn("Bearer <%s> rejected, illegal name\n", name);
427		return -EINVAL;
428	}
429	if (tipc_addr_domain_valid(disc_domain) &&
430	    (disc_domain != tipc_own_addr)) {
431		if (tipc_in_scope(disc_domain, tipc_own_addr)) {
432			disc_domain = tipc_own_addr & TIPC_CLUSTER_MASK;
433			res = 0;   /* accept any node in own cluster */
434		} else if (in_own_cluster_exact(disc_domain))
435			res = 0;   /* accept specified node in own cluster */
436	}
437	if (res) {
438		warn("Bearer <%s> rejected, illegal discovery domain\n", name);
439		return -EINVAL;
440	}
441	if ((priority > TIPC_MAX_LINK_PRI) &&
442	    (priority != TIPC_MEDIA_LINK_PRI)) {
443		warn("Bearer <%s> rejected, illegal priority\n", name);
444		return -EINVAL;
445	}
446
447	write_lock_bh(&tipc_net_lock);
448
449	m_ptr = tipc_media_find(b_names.media_name);
450	if (!m_ptr) {
451		warn("Bearer <%s> rejected, media <%s> not registered\n", name,
452		     b_names.media_name);
453		goto exit;
454	}
455
456	if (priority == TIPC_MEDIA_LINK_PRI)
457		priority = m_ptr->priority;
458
459restart:
460	bearer_id = MAX_BEARERS;
461	with_this_prio = 1;
462	for (i = MAX_BEARERS; i-- != 0; ) {
463		if (!tipc_bearers[i].active) {
464			bearer_id = i;
465			continue;
466		}
467		if (!strcmp(name, tipc_bearers[i].name)) {
468			warn("Bearer <%s> rejected, already enabled\n", name);
469			goto exit;
470		}
471		if ((tipc_bearers[i].priority == priority) &&
472		    (++with_this_prio > 2)) {
473			if (priority-- == 0) {
474				warn("Bearer <%s> rejected, duplicate priority\n",
475				     name);
476				goto exit;
477			}
478			warn("Bearer <%s> priority adjustment required %u->%u\n",
479			     name, priority + 1, priority);
480			goto restart;
481		}
482	}
483	if (bearer_id >= MAX_BEARERS) {
484		warn("Bearer <%s> rejected, bearer limit reached (%u)\n",
485		     name, MAX_BEARERS);
486		goto exit;
487	}
488
489	b_ptr = &tipc_bearers[bearer_id];
490	strcpy(b_ptr->name, name);
491	res = m_ptr->enable_bearer(b_ptr);
492	if (res) {
493		warn("Bearer <%s> rejected, enable failure (%d)\n", name, -res);
494		goto exit;
495	}
496
497	b_ptr->identity = bearer_id;
498	b_ptr->media = m_ptr;
499	b_ptr->tolerance = m_ptr->tolerance;
500	b_ptr->window = m_ptr->window;
501	b_ptr->net_plane = bearer_id + 'A';
502	b_ptr->active = 1;
503	b_ptr->priority = priority;
504	INIT_LIST_HEAD(&b_ptr->cong_links);
505	INIT_LIST_HEAD(&b_ptr->links);
506	spin_lock_init(&b_ptr->lock);
507
508	res = tipc_disc_create(b_ptr, &m_ptr->bcast_addr, disc_domain);
509	if (res) {
510		bearer_disable(b_ptr);
511		warn("Bearer <%s> rejected, discovery object creation failed\n",
512		     name);
513		goto exit;
514	}
515	info("Enabled bearer <%s>, discovery domain %s, priority %u\n",
516	     name, tipc_addr_string_fill(addr_string, disc_domain), priority);
517exit:
518	write_unlock_bh(&tipc_net_lock);
519	return res;
520}
521
522/**
523 * tipc_block_bearer(): Block the bearer with the given name,
524 *                      and reset all its links
525 */
526int tipc_block_bearer(const char *name)
527{
528	struct tipc_bearer *b_ptr = NULL;
529	struct tipc_link *l_ptr;
530	struct tipc_link *temp_l_ptr;
531
532	read_lock_bh(&tipc_net_lock);
533	b_ptr = tipc_bearer_find(name);
534	if (!b_ptr) {
535		warn("Attempt to block unknown bearer <%s>\n", name);
536		read_unlock_bh(&tipc_net_lock);
537		return -EINVAL;
538	}
539
540	info("Blocking bearer <%s>\n", name);
541	spin_lock_bh(&b_ptr->lock);
542	b_ptr->blocked = 1;
543	list_splice_init(&b_ptr->cong_links, &b_ptr->links);
544	list_for_each_entry_safe(l_ptr, temp_l_ptr, &b_ptr->links, link_list) {
545		struct tipc_node *n_ptr = l_ptr->owner;
546
547		spin_lock_bh(&n_ptr->lock);
548		tipc_link_reset(l_ptr);
549		spin_unlock_bh(&n_ptr->lock);
550	}
551	spin_unlock_bh(&b_ptr->lock);
552	read_unlock_bh(&tipc_net_lock);
553	return 0;
554}
555
556/**
557 * bearer_disable
558 *
559 * Note: This routine assumes caller holds tipc_net_lock.
560 */
561static void bearer_disable(struct tipc_bearer *b_ptr)
562{
563	struct tipc_link *l_ptr;
564	struct tipc_link *temp_l_ptr;
565
566	info("Disabling bearer <%s>\n", b_ptr->name);
567	spin_lock_bh(&b_ptr->lock);
568	b_ptr->blocked = 1;
569	b_ptr->media->disable_bearer(b_ptr);
570	list_splice_init(&b_ptr->cong_links, &b_ptr->links);
571	list_for_each_entry_safe(l_ptr, temp_l_ptr, &b_ptr->links, link_list) {
572		tipc_link_delete(l_ptr);
573	}
574	if (b_ptr->link_req)
575		tipc_disc_delete(b_ptr->link_req);
576	spin_unlock_bh(&b_ptr->lock);
577	memset(b_ptr, 0, sizeof(struct tipc_bearer));
578}
579
580int tipc_disable_bearer(const char *name)
581{
582	struct tipc_bearer *b_ptr;
583	int res;
584
585	write_lock_bh(&tipc_net_lock);
586	b_ptr = tipc_bearer_find(name);
587	if (b_ptr == NULL) {
588		warn("Attempt to disable unknown bearer <%s>\n", name);
589		res = -EINVAL;
590	} else {
591		bearer_disable(b_ptr);
592		res = 0;
593	}
594	write_unlock_bh(&tipc_net_lock);
595	return res;
596}
597
598
599
600void tipc_bearer_stop(void)
601{
602	u32 i;
603
604	for (i = 0; i < MAX_BEARERS; i++) {
605		if (tipc_bearers[i].active)
606			bearer_disable(&tipc_bearers[i]);
607	}
608	media_count = 0;
609}