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Vlad Yasevich60c778b2008-01-11 09:57:09 -05001/* SCTP kernel implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * Copyright (c) 1999-2000 Cisco, Inc.
3 * Copyright (c) 1999-2001 Motorola, Inc.
4 * Copyright (c) 2001-2003 International Business Machines, Corp.
5 * Copyright (c) 2001 Intel Corp.
6 * Copyright (c) 2001 Nokia, Inc.
7 * Copyright (c) 2001 La Monte H.P. Yarroll
8 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -05009 * This file is part of the SCTP kernel implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 *
11 * These functions handle all input from the IP layer into SCTP.
12 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -050013 * This SCTP implementation is free software;
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 * you can redistribute it and/or modify it under the terms of
15 * the GNU General Public License as published by
16 * the Free Software Foundation; either version 2, or (at your option)
17 * any later version.
18 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -050019 * This SCTP implementation is distributed in the hope that it
Linus Torvalds1da177e2005-04-16 15:20:36 -070020 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
21 * ************************
22 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
23 * See the GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public License
26 * along with GNU CC; see the file COPYING. If not, write to
27 * the Free Software Foundation, 59 Temple Place - Suite 330,
28 * Boston, MA 02111-1307, USA.
29 *
30 * Please send any bug reports or fixes you make to the
31 * email address(es):
32 * lksctp developers <lksctp-developers@lists.sourceforge.net>
33 *
34 * Or submit a bug report through the following website:
35 * http://www.sf.net/projects/lksctp
36 *
37 * Written or modified by:
38 * La Monte H.P. Yarroll <piggy@acm.org>
39 * Karl Knutson <karl@athena.chicago.il.us>
40 * Xingang Guo <xingang.guo@intel.com>
41 * Jon Grimm <jgrimm@us.ibm.com>
42 * Hui Huang <hui.huang@nokia.com>
43 * Daisy Chang <daisyc@us.ibm.com>
44 * Sridhar Samudrala <sri@us.ibm.com>
45 * Ardelle Fan <ardelle.fan@intel.com>
46 *
47 * Any bugs reported given to us we will try to fix... any fixes shared will
48 * be incorporated into the next SCTP release.
49 */
50
51#include <linux/types.h>
52#include <linux/list.h> /* For struct list_head */
53#include <linux/socket.h>
54#include <linux/ip.h>
55#include <linux/time.h> /* For struct timeval */
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090056#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070057#include <net/ip.h>
58#include <net/icmp.h>
59#include <net/snmp.h>
60#include <net/sock.h>
61#include <net/xfrm.h>
62#include <net/sctp/sctp.h>
63#include <net/sctp/sm.h>
Vlad Yasevich9ad09772007-12-16 14:06:41 -080064#include <net/sctp/checksum.h>
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -070065#include <net/net_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070066
67/* Forward declarations for internal helpers. */
68static int sctp_rcv_ootb(struct sk_buff *);
69static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
70 const union sctp_addr *laddr,
71 const union sctp_addr *paddr,
72 struct sctp_transport **transportp);
73static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr);
74static struct sctp_association *__sctp_lookup_association(
75 const union sctp_addr *local,
76 const union sctp_addr *peer,
77 struct sctp_transport **pt);
78
Zhu Yi50b1a782010-03-04 18:01:44 +000079static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -070080
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
82/* Calculate the SCTP checksum of an SCTP packet. */
83static inline int sctp_rcv_checksum(struct sk_buff *skb)
84{
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -030085 struct sctphdr *sh = sctp_hdr(skb);
Vlad Yasevich4458f042009-02-13 08:33:42 +000086 __le32 cmp = sh->checksum;
David S. Miller1b003be2009-06-09 00:22:35 -070087 struct sk_buff *list;
Vlad Yasevich4458f042009-02-13 08:33:42 +000088 __le32 val;
89 __u32 tmp = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
David S. Miller1b003be2009-06-09 00:22:35 -070091 skb_walk_frags(skb, list)
Vlad Yasevich4458f042009-02-13 08:33:42 +000092 tmp = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
93 tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
Vlad Yasevich4458f042009-02-13 08:33:42 +000095 val = sctp_end_cksum(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97 if (val != cmp) {
98 /* CRC failure, dump it. */
99 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS);
100 return -1;
101 }
102 return 0;
103}
104
David S. Miller79af02c2005-07-08 21:47:49 -0700105struct sctp_input_cb {
106 union {
107 struct inet_skb_parm h4;
108#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
109 struct inet6_skb_parm h6;
110#endif
111 } header;
112 struct sctp_chunk *chunk;
113};
114#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116/*
117 * This is the routine which IP calls when receiving an SCTP packet.
118 */
119int sctp_rcv(struct sk_buff *skb)
120{
121 struct sock *sk;
122 struct sctp_association *asoc;
123 struct sctp_endpoint *ep = NULL;
124 struct sctp_ep_common *rcvr;
125 struct sctp_transport *transport = NULL;
126 struct sctp_chunk *chunk;
127 struct sctphdr *sh;
128 union sctp_addr src;
129 union sctp_addr dest;
130 int family;
131 struct sctp_af *af;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
133 if (skb->pkt_type!=PACKET_HOST)
134 goto discard_it;
135
136 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS);
137
Herbert Xu28cd7752006-10-29 23:46:42 -0800138 if (skb_linearize(skb))
139 goto discard_it;
140
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -0300141 sh = sctp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
143 /* Pull up the IP and SCTP headers. */
Arnaldo Carvalho de Meloea2ae172007-04-25 17:55:53 -0700144 __skb_pull(skb, skb_transport_offset(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 if (skb->len < sizeof(struct sctphdr))
146 goto discard_it;
Lucas Nussbaum06e86802009-02-13 08:33:41 +0000147 if (!sctp_checksum_disable && !skb_csum_unnecessary(skb) &&
148 sctp_rcv_checksum(skb) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 goto discard_it;
150
151 skb_pull(skb, sizeof(struct sctphdr));
152
153 /* Make sure we at least have chunk headers worth of data left. */
154 if (skb->len < sizeof(struct sctp_chunkhdr))
155 goto discard_it;
156
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700157 family = ipver2af(ip_hdr(skb)->version);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 af = sctp_get_af_specific(family);
159 if (unlikely(!af))
160 goto discard_it;
161
162 /* Initialize local addresses for lookups. */
163 af->from_skb(&src, skb, 1);
164 af->from_skb(&dest, skb, 0);
165
166 /* If the packet is to or from a non-unicast address,
167 * silently discard the packet.
168 *
169 * This is not clearly defined in the RFC except in section
170 * 8.4 - OOTB handling. However, based on the book "Stream Control
171 * Transmission Protocol" 2.1, "It is important to note that the
172 * IP address of an SCTP transport address must be a routable
173 * unicast address. In other words, IP multicast addresses and
174 * IP broadcast addresses cannot be used in an SCTP transport
175 * address."
176 */
Vlad Yasevich5636bef2006-06-17 22:55:35 -0700177 if (!af->addr_valid(&src, NULL, skb) ||
178 !af->addr_valid(&dest, NULL, skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 goto discard_it;
180
Al Virod55c41b2006-11-20 17:09:40 -0800181 asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport);
Al Viro1c7d1fc2006-11-20 17:08:09 -0800182
Neil Horman0fd9a652005-06-13 15:11:24 -0700183 if (!asoc)
Al Virod55c41b2006-11-20 17:09:40 -0800184 ep = __sctp_rcv_lookup_endpoint(&dest);
Neil Horman0fd9a652005-06-13 15:11:24 -0700185
186 /* Retrieve the common input handling substructure. */
187 rcvr = asoc ? &asoc->base : &ep->base;
188 sk = rcvr->sk;
189
190 /*
191 * If a frame arrives on an interface and the receiving socket is
192 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
193 */
194 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb)))
195 {
Neil Horman0fd9a652005-06-13 15:11:24 -0700196 if (asoc) {
197 sctp_association_put(asoc);
198 asoc = NULL;
199 } else {
200 sctp_endpoint_put(ep);
201 ep = NULL;
202 }
203 sk = sctp_get_ctl_sock();
204 ep = sctp_sk(sk)->ep;
205 sctp_endpoint_hold(ep);
Neil Horman0fd9a652005-06-13 15:11:24 -0700206 rcvr = &ep->base;
207 }
208
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 /*
210 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
211 * An SCTP packet is called an "out of the blue" (OOTB)
212 * packet if it is correctly formed, i.e., passed the
213 * receiver's checksum check, but the receiver is not
214 * able to identify the association to which this
215 * packet belongs.
216 */
217 if (!asoc) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 if (sctp_rcv_ootb(skb)) {
219 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES);
220 goto discard_release;
221 }
222 }
223
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
225 goto discard_release;
Patrick McHardyb59c2702006-01-06 23:06:10 -0800226 nf_reset(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
Dmitry Mishinfda9ef52006-08-31 15:28:39 -0700228 if (sk_filter(sk, skb))
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900229 goto discard_release;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
231 /* Create an SCTP packet structure. */
232 chunk = sctp_chunkify(skb, asoc, sk);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800233 if (!chunk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 goto discard_release;
David S. Miller79af02c2005-07-08 21:47:49 -0700235 SCTP_INPUT_CB(skb)->chunk = chunk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 /* Remember what endpoint is to handle this packet. */
238 chunk->rcvr = rcvr;
239
240 /* Remember the SCTP header. */
241 chunk->sctp_hdr = sh;
242
243 /* Set the source and destination addresses of the incoming chunk. */
Al Virod55c41b2006-11-20 17:09:40 -0800244 sctp_init_addrs(chunk, &src, &dest);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245
246 /* Remember where we came from. */
247 chunk->transport = transport;
248
249 /* Acquire access to the sock lock. Note: We are safe from other
250 * bottom halves on this lock, but a user may be in the lock too,
251 * so check if it is busy.
252 */
253 sctp_bh_lock_sock(sk);
254
Vlad Yasevichae53b5b2009-01-22 14:53:23 -0800255 if (sk != rcvr->sk) {
256 /* Our cached sk is different from the rcvr->sk. This is
257 * because migrate()/accept() may have moved the association
258 * to a new socket and released all the sockets. So now we
259 * are holding a lock on the old socket while the user may
260 * be doing something with the new socket. Switch our veiw
261 * of the current sk.
262 */
263 sctp_bh_unlock_sock(sk);
264 sk = rcvr->sk;
265 sctp_bh_lock_sock(sk);
266 }
267
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700268 if (sock_owned_by_user(sk)) {
Zhu Yi50b1a782010-03-04 18:01:44 +0000269 if (sctp_add_backlog(sk, skb)) {
270 sctp_bh_unlock_sock(sk);
271 sctp_chunk_free(chunk);
272 skb = NULL; /* sctp_chunk_free already freed the skb */
273 goto discard_release;
274 }
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700275 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG);
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700276 } else {
277 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700278 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700279 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 sctp_bh_unlock_sock(sk);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700282
283 /* Release the asoc/ep ref we took in the lookup calls. */
284 if (asoc)
285 sctp_association_put(asoc);
286 else
287 sctp_endpoint_put(ep);
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800288
Herbert Xu2babf9d2006-03-25 01:25:29 -0800289 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290
291discard_it:
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700292 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 kfree_skb(skb);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800294 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295
296discard_release:
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700297 /* Release the asoc/ep ref we took in the lookup calls. */
Neil Horman0fd9a652005-06-13 15:11:24 -0700298 if (asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 sctp_association_put(asoc);
Neil Horman0fd9a652005-06-13 15:11:24 -0700300 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 sctp_endpoint_put(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302
303 goto discard_it;
304}
305
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700306/* Process the backlog queue of the socket. Every skb on
307 * the backlog holds a ref on an association or endpoint.
308 * We hold this ref throughout the state machine to make
309 * sure that the structure we need is still around.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 */
311int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
312{
David S. Miller79af02c2005-07-08 21:47:49 -0700313 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900314 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
315 struct sctp_ep_common *rcvr = NULL;
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700316 int backloged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900318 rcvr = chunk->rcvr;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800319
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700320 /* If the rcvr is dead then the association or endpoint
321 * has been deleted and we can safely drop the chunk
322 * and refs that we are holding.
323 */
324 if (rcvr->dead) {
325 sctp_chunk_free(chunk);
326 goto done;
327 }
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800328
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700329 if (unlikely(rcvr->sk != sk)) {
330 /* In this case, the association moved from one socket to
331 * another. We are currently sitting on the backlog of the
332 * old socket, so we need to move.
333 * However, since we are here in the process context we
334 * need to take make sure that the user doesn't own
335 * the new socket when we process the packet.
336 * If the new socket is user-owned, queue the chunk to the
337 * backlog of the new socket without dropping any refs.
338 * Otherwise, we can safely push the chunk on the inqueue.
339 */
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800340
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700341 sk = rcvr->sk;
342 sctp_bh_lock_sock(sk);
343
344 if (sock_owned_by_user(sk)) {
Zhu Yia3a858f2010-03-04 18:01:47 +0000345 if (sk_add_backlog(sk, skb))
Zhu Yi50b1a782010-03-04 18:01:44 +0000346 sctp_chunk_free(chunk);
347 else
348 backloged = 1;
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700349 } else
350 sctp_inq_push(inqueue, chunk);
351
352 sctp_bh_unlock_sock(sk);
353
354 /* If the chunk was backloged again, don't drop refs */
355 if (backloged)
356 return 0;
357 } else {
358 sctp_inq_push(inqueue, chunk);
359 }
360
361done:
362 /* Release the refs we took in sctp_add_backlog */
363 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
364 sctp_association_put(sctp_assoc(rcvr));
365 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
366 sctp_endpoint_put(sctp_ep(rcvr));
367 else
368 BUG();
369
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900370 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371}
372
Zhu Yi50b1a782010-03-04 18:01:44 +0000373static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800374{
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700375 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
376 struct sctp_ep_common *rcvr = chunk->rcvr;
Zhu Yi50b1a782010-03-04 18:01:44 +0000377 int ret;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800378
Zhu Yia3a858f2010-03-04 18:01:47 +0000379 ret = sk_add_backlog(sk, skb);
Zhu Yi50b1a782010-03-04 18:01:44 +0000380 if (!ret) {
381 /* Hold the assoc/ep while hanging on the backlog queue.
382 * This way, we know structures we need will not disappear
383 * from us
384 */
385 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
386 sctp_association_hold(sctp_assoc(rcvr));
387 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
388 sctp_endpoint_hold(sctp_ep(rcvr));
389 else
390 BUG();
391 }
392 return ret;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800393
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800394}
395
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396/* Handle icmp frag needed error. */
397void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
398 struct sctp_transport *t, __u32 pmtu)
399{
Wei Yongjun91bd6b12008-10-23 00:59:52 -0700400 if (!t || (t->pathmtu <= pmtu))
Frank Filz52ccb8e2005-12-22 11:36:46 -0800401 return;
402
Vlad Yasevich8a479492007-06-07 14:21:05 -0400403 if (sock_owned_by_user(sk)) {
404 asoc->pmtu_pending = 1;
405 t->pmtu_pending = 1;
406 return;
407 }
408
Frank Filz52ccb8e2005-12-22 11:36:46 -0800409 if (t->param_flags & SPP_PMTUD_ENABLE) {
Vlad Yasevichc910b472007-06-07 13:47:03 -0400410 /* Update transports view of the MTU */
411 sctp_transport_update_pmtu(t, pmtu);
Frank Filz52ccb8e2005-12-22 11:36:46 -0800412
413 /* Update association pmtu. */
414 sctp_assoc_sync_pmtu(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 }
416
Frank Filz52ccb8e2005-12-22 11:36:46 -0800417 /* Retransmit with the new pmtu setting.
418 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
419 * Needed will never be sent, but if a message was sent before
420 * PMTU discovery was disabled that was larger than the PMTU, it
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900421 * would not be fragmented, so it must be re-transmitted fragmented.
Frank Filz52ccb8e2005-12-22 11:36:46 -0800422 */
423 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424}
425
426/*
427 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
428 *
429 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
430 * or a "Protocol Unreachable" treat this message as an abort
431 * with the T bit set.
432 *
433 * This function sends an event to the state machine, which will abort the
434 * association.
435 *
436 */
437void sctp_icmp_proto_unreachable(struct sock *sk,
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900438 struct sctp_association *asoc,
439 struct sctp_transport *t)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440{
Harvey Harrison0dc47872008-03-05 20:47:47 -0800441 SCTP_DEBUG_PRINTK("%s\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442
Vlad Yasevich50b5d6a2010-05-06 00:56:07 -0700443 if (sock_owned_by_user(sk)) {
444 if (timer_pending(&t->proto_unreach_timer))
445 return;
446 else {
447 if (!mod_timer(&t->proto_unreach_timer,
448 jiffies + (HZ/20)))
449 sctp_association_hold(asoc);
450 }
451
452 } else {
453 if (timer_pending(&t->proto_unreach_timer) &&
454 del_timer(&t->proto_unreach_timer))
455 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456
Vlad Yasevich50b5d6a2010-05-06 00:56:07 -0700457 sctp_do_sm(SCTP_EVENT_T_OTHER,
458 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
459 asoc->state, asoc->ep, asoc, t,
460 GFP_ATOMIC);
461 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462}
463
464/* Common lookup code for icmp/icmpv6 error handler. */
465struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
466 struct sctphdr *sctphdr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 struct sctp_association **app,
468 struct sctp_transport **tpp)
469{
470 union sctp_addr saddr;
471 union sctp_addr daddr;
472 struct sctp_af *af;
473 struct sock *sk = NULL;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700474 struct sctp_association *asoc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 struct sctp_transport *transport = NULL;
Wei Yongjun7115e632008-06-19 16:07:48 -0700476 struct sctp_init_chunk *chunkhdr;
477 __u32 vtag = ntohl(sctphdr->vtag);
478 int len = skb->len - ((void *)sctphdr - (void *)skb->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700480 *app = NULL; *tpp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481
482 af = sctp_get_af_specific(family);
483 if (unlikely(!af)) {
484 return NULL;
485 }
486
487 /* Initialize local addresses for lookups. */
488 af->from_skb(&saddr, skb, 1);
489 af->from_skb(&daddr, skb, 0);
490
491 /* Look for an association that matches the incoming ICMP error
492 * packet.
493 */
Al Virod55c41b2006-11-20 17:09:40 -0800494 asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700495 if (!asoc)
496 return NULL;
497
498 sk = asoc->base.sk;
499
Wei Yongjun7115e632008-06-19 16:07:48 -0700500 /* RFC 4960, Appendix C. ICMP Handling
501 *
502 * ICMP6) An implementation MUST validate that the Verification Tag
503 * contained in the ICMP message matches the Verification Tag of
504 * the peer. If the Verification Tag is not 0 and does NOT
505 * match, discard the ICMP message. If it is 0 and the ICMP
506 * message contains enough bytes to verify that the chunk type is
507 * an INIT chunk and that the Initiate Tag matches the tag of the
508 * peer, continue with ICMP7. If the ICMP message is too short
509 * or the chunk type or the Initiate Tag does not match, silently
510 * discard the packet.
511 */
512 if (vtag == 0) {
513 chunkhdr = (struct sctp_init_chunk *)((void *)sctphdr
514 + sizeof(struct sctphdr));
515 if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
516 + sizeof(__be32) ||
517 chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
518 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) {
519 goto out;
520 }
521 } else if (vtag != asoc->c.peer_vtag) {
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700522 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 }
524
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 sctp_bh_lock_sock(sk);
526
527 /* If too many ICMPs get dropped on busy
528 * servers this needs to be solved differently.
529 */
530 if (sock_owned_by_user(sk))
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700531 NET_INC_STATS_BH(&init_net, LINUX_MIB_LOCKDROPPEDICMPS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 *app = asoc;
534 *tpp = transport;
535 return sk;
536
537out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 if (asoc)
539 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 return NULL;
541}
542
543/* Common cleanup code for icmp/icmpv6 error handler. */
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700544void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545{
546 sctp_bh_unlock_sock(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 if (asoc)
548 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549}
550
551/*
552 * This routine is called by the ICMP module when it gets some
553 * sort of error condition. If err < 0 then the socket should
554 * be closed and the error returned to the user. If err > 0
555 * it's just the icmp type << 8 | icmp code. After adjustment
556 * header points to the first 8 bytes of the sctp header. We need
557 * to find the appropriate port.
558 *
559 * The locking strategy used here is very "optimistic". When
560 * someone else accesses the socket the ICMP is just dropped
561 * and for some paths there is no check at all.
562 * A more general error queue to queue errors for later handling
563 * is probably better.
564 *
565 */
566void sctp_v4_err(struct sk_buff *skb, __u32 info)
567{
568 struct iphdr *iph = (struct iphdr *)skb->data;
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300569 const int ihlen = iph->ihl * 4;
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300570 const int type = icmp_hdr(skb)->type;
571 const int code = icmp_hdr(skb)->code;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 struct sock *sk;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700573 struct sctp_association *asoc = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 struct sctp_transport *transport;
575 struct inet_sock *inet;
Arnaldo Carvalho de Melo2e07fa92007-04-10 21:22:35 -0700576 sk_buff_data_t saveip, savesctp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 int err;
578
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300579 if (skb->len < ihlen + 8) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700580 ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 return;
582 }
583
584 /* Fix up skb to look at the embedded net header. */
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700585 saveip = skb->network_header;
586 savesctp = skb->transport_header;
Arnaldo Carvalho de Melo31c77112007-03-10 19:04:55 -0300587 skb_reset_network_header(skb);
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300588 skb_set_transport_header(skb, ihlen);
589 sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
Arnaldo Carvalho de Melo2e07fa92007-04-10 21:22:35 -0700590 /* Put back, the original values. */
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700591 skb->network_header = saveip;
592 skb->transport_header = savesctp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 if (!sk) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700594 ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 return;
596 }
597 /* Warning: The sock lock is held. Remember to call
598 * sctp_err_finish!
599 */
600
601 switch (type) {
602 case ICMP_PARAMETERPROB:
603 err = EPROTO;
604 break;
605 case ICMP_DEST_UNREACH:
606 if (code > NR_ICMP_UNREACH)
607 goto out_unlock;
608
609 /* PMTU discovery (RFC1191) */
610 if (ICMP_FRAG_NEEDED == code) {
611 sctp_icmp_frag_needed(sk, asoc, transport, info);
612 goto out_unlock;
613 }
614 else {
615 if (ICMP_PROT_UNREACH == code) {
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700616 sctp_icmp_proto_unreachable(sk, asoc,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 transport);
618 goto out_unlock;
619 }
620 }
621 err = icmp_err_convert[code].errno;
622 break;
623 case ICMP_TIME_EXCEEDED:
624 /* Ignore any time exceeded errors due to fragment reassembly
625 * timeouts.
626 */
627 if (ICMP_EXC_FRAGTIME == code)
628 goto out_unlock;
629
630 err = EHOSTUNREACH;
631 break;
632 default:
633 goto out_unlock;
634 }
635
636 inet = inet_sk(sk);
637 if (!sock_owned_by_user(sk) && inet->recverr) {
638 sk->sk_err = err;
639 sk->sk_error_report(sk);
640 } else { /* Only an error on timeout */
641 sk->sk_err_soft = err;
642 }
643
644out_unlock:
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700645 sctp_err_finish(sk, asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646}
647
648/*
649 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
650 *
651 * This function scans all the chunks in the OOTB packet to determine if
652 * the packet should be discarded right away. If a response might be needed
653 * for this packet, or, if further processing is possible, the packet will
654 * be queued to a proper inqueue for the next phase of handling.
655 *
656 * Output:
657 * Return 0 - If further processing is needed.
658 * Return 1 - If the packet can be discarded right away.
659 */
sebastian@breakpoint.cc04675212007-07-26 23:21:31 +0200660static int sctp_rcv_ootb(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661{
662 sctp_chunkhdr_t *ch;
663 __u8 *ch_end;
664 sctp_errhdr_t *err;
665
666 ch = (sctp_chunkhdr_t *) skb->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667
668 /* Scan through all the chunks in the packet. */
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800669 do {
670 /* Break out if chunk length is less then minimal. */
671 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
672 break;
673
674 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700675 if (ch_end > skb_tail_pointer(skb))
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800676 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677
678 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
679 * receiver MUST silently discard the OOTB packet and take no
680 * further action.
681 */
682 if (SCTP_CID_ABORT == ch->type)
683 goto discard;
684
685 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
686 * chunk, the receiver should silently discard the packet
687 * and take no further action.
688 */
689 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
690 goto discard;
691
Vlad Yasevich3c77f962007-09-17 15:14:28 -0400692 /* RFC 4460, 2.11.2
693 * This will discard packets with INIT chunk bundled as
694 * subsequent chunks in the packet. When INIT is first,
695 * the normal INIT processing will discard the chunk.
696 */
697 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
698 goto discard;
699
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
701 * or a COOKIE ACK the SCTP Packet should be silently
702 * discarded.
703 */
704 if (SCTP_CID_COOKIE_ACK == ch->type)
705 goto discard;
706
707 if (SCTP_CID_ERROR == ch->type) {
708 sctp_walk_errors(err, ch) {
709 if (SCTP_ERROR_STALE_COOKIE == err->cause)
710 goto discard;
711 }
712 }
713
714 ch = (sctp_chunkhdr_t *) ch_end;
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700715 } while (ch_end < skb_tail_pointer(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716
717 return 0;
718
719discard:
720 return 1;
721}
722
723/* Insert endpoint into the hash table. */
724static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
725{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 struct sctp_ep_common *epb;
727 struct sctp_hashbucket *head;
728
729 epb = &ep->base;
730
731 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
732 head = &sctp_ep_hashtable[epb->hashent];
733
734 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500735 hlist_add_head(&epb->node, &head->chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 sctp_write_unlock(&head->lock);
737}
738
739/* Add an endpoint to the hash. Local BH-safe. */
740void sctp_hash_endpoint(struct sctp_endpoint *ep)
741{
742 sctp_local_bh_disable();
743 __sctp_hash_endpoint(ep);
744 sctp_local_bh_enable();
745}
746
747/* Remove endpoint from the hash table. */
748static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
749{
750 struct sctp_hashbucket *head;
751 struct sctp_ep_common *epb;
752
753 epb = &ep->base;
754
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500755 if (hlist_unhashed(&epb->node))
756 return;
757
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
759
760 head = &sctp_ep_hashtable[epb->hashent];
761
762 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500763 __hlist_del(&epb->node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 sctp_write_unlock(&head->lock);
765}
766
767/* Remove endpoint from the hash. Local BH-safe. */
768void sctp_unhash_endpoint(struct sctp_endpoint *ep)
769{
770 sctp_local_bh_disable();
771 __sctp_unhash_endpoint(ep);
772 sctp_local_bh_enable();
773}
774
775/* Look up an endpoint. */
776static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr)
777{
778 struct sctp_hashbucket *head;
779 struct sctp_ep_common *epb;
780 struct sctp_endpoint *ep;
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500781 struct hlist_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 int hash;
783
Al Viro1c7d1fc2006-11-20 17:08:09 -0800784 hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785 head = &sctp_ep_hashtable[hash];
786 read_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500787 sctp_for_each_hentry(epb, node, &head->chain) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 ep = sctp_ep(epb);
789 if (sctp_endpoint_is_match(ep, laddr))
790 goto hit;
791 }
792
793 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794
795hit:
796 sctp_endpoint_hold(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 read_unlock(&head->lock);
798 return ep;
799}
800
801/* Insert association into the hash table. */
802static void __sctp_hash_established(struct sctp_association *asoc)
803{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 struct sctp_ep_common *epb;
805 struct sctp_hashbucket *head;
806
807 epb = &asoc->base;
808
809 /* Calculate which chain this entry will belong to. */
810 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port);
811
812 head = &sctp_assoc_hashtable[epb->hashent];
813
814 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500815 hlist_add_head(&epb->node, &head->chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 sctp_write_unlock(&head->lock);
817}
818
819/* Add an association to the hash. Local BH-safe. */
820void sctp_hash_established(struct sctp_association *asoc)
821{
Vlad Yasevichde76e692006-10-30 18:55:11 -0800822 if (asoc->temp)
823 return;
824
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 sctp_local_bh_disable();
826 __sctp_hash_established(asoc);
827 sctp_local_bh_enable();
828}
829
830/* Remove association from the hash table. */
831static void __sctp_unhash_established(struct sctp_association *asoc)
832{
833 struct sctp_hashbucket *head;
834 struct sctp_ep_common *epb;
835
836 epb = &asoc->base;
837
838 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port,
839 asoc->peer.port);
840
841 head = &sctp_assoc_hashtable[epb->hashent];
842
843 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500844 __hlist_del(&epb->node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845 sctp_write_unlock(&head->lock);
846}
847
848/* Remove association from the hash table. Local BH-safe. */
849void sctp_unhash_established(struct sctp_association *asoc)
850{
Vlad Yasevichde76e692006-10-30 18:55:11 -0800851 if (asoc->temp)
852 return;
853
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 sctp_local_bh_disable();
855 __sctp_unhash_established(asoc);
856 sctp_local_bh_enable();
857}
858
859/* Look up an association. */
860static struct sctp_association *__sctp_lookup_association(
861 const union sctp_addr *local,
862 const union sctp_addr *peer,
863 struct sctp_transport **pt)
864{
865 struct sctp_hashbucket *head;
866 struct sctp_ep_common *epb;
867 struct sctp_association *asoc;
868 struct sctp_transport *transport;
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500869 struct hlist_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 int hash;
871
872 /* Optimize here for direct hit, only listening connections can
873 * have wildcards anyways.
874 */
Al Viroe2fcced2006-11-20 17:08:41 -0800875 hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 head = &sctp_assoc_hashtable[hash];
877 read_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500878 sctp_for_each_hentry(epb, node, &head->chain) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 asoc = sctp_assoc(epb);
880 transport = sctp_assoc_is_match(asoc, local, peer);
881 if (transport)
882 goto hit;
883 }
884
885 read_unlock(&head->lock);
886
887 return NULL;
888
889hit:
890 *pt = transport;
891 sctp_association_hold(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 read_unlock(&head->lock);
893 return asoc;
894}
895
896/* Look up an association. BH-safe. */
897SCTP_STATIC
898struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr,
899 const union sctp_addr *paddr,
900 struct sctp_transport **transportp)
901{
902 struct sctp_association *asoc;
903
904 sctp_local_bh_disable();
905 asoc = __sctp_lookup_association(laddr, paddr, transportp);
906 sctp_local_bh_enable();
907
908 return asoc;
909}
910
911/* Is there an association matching the given local and peer addresses? */
912int sctp_has_association(const union sctp_addr *laddr,
913 const union sctp_addr *paddr)
914{
915 struct sctp_association *asoc;
916 struct sctp_transport *transport;
917
Al Viro6c7be552006-11-20 17:11:50 -0800918 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 sctp_association_put(asoc);
920 return 1;
921 }
922
923 return 0;
924}
925
926/*
927 * SCTP Implementors Guide, 2.18 Handling of address
928 * parameters within the INIT or INIT-ACK.
929 *
930 * D) When searching for a matching TCB upon reception of an INIT
931 * or INIT-ACK chunk the receiver SHOULD use not only the
932 * source address of the packet (containing the INIT or
933 * INIT-ACK) but the receiver SHOULD also use all valid
934 * address parameters contained within the chunk.
935 *
936 * 2.18.3 Solution description
937 *
938 * This new text clearly specifies to an implementor the need
939 * to look within the INIT or INIT-ACK. Any implementation that
940 * does not do this, may not be able to establish associations
941 * in certain circumstances.
942 *
943 */
944static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
945 const union sctp_addr *laddr, struct sctp_transport **transportp)
946{
947 struct sctp_association *asoc;
948 union sctp_addr addr;
949 union sctp_addr *paddr = &addr;
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -0300950 struct sctphdr *sh = sctp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951 sctp_chunkhdr_t *ch;
952 union sctp_params params;
953 sctp_init_chunk_t *init;
954 struct sctp_transport *transport;
955 struct sctp_af *af;
956
957 ch = (sctp_chunkhdr_t *) skb->data;
958
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 /*
960 * This code will NOT touch anything inside the chunk--it is
961 * strictly READ-ONLY.
962 *
963 * RFC 2960 3 SCTP packet Format
964 *
965 * Multiple chunks can be bundled into one SCTP packet up to
966 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
967 * COMPLETE chunks. These chunks MUST NOT be bundled with any
968 * other chunk in a packet. See Section 6.10 for more details
969 * on chunk bundling.
970 */
971
972 /* Find the start of the TLVs and the end of the chunk. This is
973 * the region we search for address parameters.
974 */
975 init = (sctp_init_chunk_t *)skb->data;
976
977 /* Walk the parameters looking for embedded addresses. */
978 sctp_walk_params(params, init, init_hdr.params) {
979
980 /* Note: Ignoring hostname addresses. */
981 af = sctp_get_af_specific(param_type2af(params.p->type));
982 if (!af)
983 continue;
984
Al Virodd86d132006-11-20 17:11:13 -0800985 af->from_addr_param(paddr, params.addr, sh->source, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986
Al Virodd86d132006-11-20 17:11:13 -0800987 asoc = __sctp_lookup_association(laddr, paddr, &transport);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 if (asoc)
989 return asoc;
990 }
991
992 return NULL;
993}
994
Vlad Yasevichdf218572007-12-20 14:10:38 -0800995/* ADD-IP, Section 5.2
996 * When an endpoint receives an ASCONF Chunk from the remote peer
997 * special procedures may be needed to identify the association the
998 * ASCONF Chunk is associated with. To properly find the association
999 * the following procedures SHOULD be followed:
1000 *
1001 * D2) If the association is not found, use the address found in the
1002 * Address Parameter TLV combined with the port number found in the
1003 * SCTP common header. If found proceed to rule D4.
1004 *
1005 * D2-ext) If more than one ASCONF Chunks are packed together, use the
1006 * address found in the ASCONF Address Parameter TLV of each of the
1007 * subsequent ASCONF Chunks. If found, proceed to rule D4.
1008 */
1009static struct sctp_association *__sctp_rcv_asconf_lookup(
1010 sctp_chunkhdr_t *ch,
1011 const union sctp_addr *laddr,
Al Virobc92dd12008-03-17 22:47:32 -07001012 __be16 peer_port,
Vlad Yasevichdf218572007-12-20 14:10:38 -08001013 struct sctp_transport **transportp)
1014{
1015 sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch;
1016 struct sctp_af *af;
1017 union sctp_addr_param *param;
1018 union sctp_addr paddr;
1019
1020 /* Skip over the ADDIP header and find the Address parameter */
1021 param = (union sctp_addr_param *)(asconf + 1);
1022
1023 af = sctp_get_af_specific(param_type2af(param->v4.param_hdr.type));
1024 if (unlikely(!af))
1025 return NULL;
1026
1027 af->from_addr_param(&paddr, param, peer_port, 0);
1028
1029 return __sctp_lookup_association(laddr, &paddr, transportp);
1030}
1031
1032
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001033/* SCTP-AUTH, Section 6.3:
1034* If the receiver does not find a STCB for a packet containing an AUTH
1035* chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1036* chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1037* association.
1038*
1039* This means that any chunks that can help us identify the association need
1040* to be looked at to find this assocation.
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001041*/
Vlad Yasevichdf218572007-12-20 14:10:38 -08001042static struct sctp_association *__sctp_rcv_walk_lookup(struct sk_buff *skb,
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001043 const union sctp_addr *laddr,
1044 struct sctp_transport **transportp)
1045{
Vlad Yasevichdf218572007-12-20 14:10:38 -08001046 struct sctp_association *asoc = NULL;
1047 sctp_chunkhdr_t *ch;
1048 int have_auth = 0;
1049 unsigned int chunk_num = 1;
1050 __u8 *ch_end;
1051
1052 /* Walk through the chunks looking for AUTH or ASCONF chunks
1053 * to help us find the association.
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001054 */
Vlad Yasevichdf218572007-12-20 14:10:38 -08001055 ch = (sctp_chunkhdr_t *) skb->data;
1056 do {
1057 /* Break out if chunk length is less then minimal. */
1058 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
1059 break;
1060
1061 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
1062 if (ch_end > skb_tail_pointer(skb))
1063 break;
1064
1065 switch(ch->type) {
1066 case SCTP_CID_AUTH:
1067 have_auth = chunk_num;
1068 break;
1069
1070 case SCTP_CID_COOKIE_ECHO:
1071 /* If a packet arrives containing an AUTH chunk as
1072 * a first chunk, a COOKIE-ECHO chunk as the second
1073 * chunk, and possibly more chunks after them, and
1074 * the receiver does not have an STCB for that
1075 * packet, then authentication is based on
1076 * the contents of the COOKIE- ECHO chunk.
1077 */
1078 if (have_auth == 1 && chunk_num == 2)
1079 return NULL;
1080 break;
1081
1082 case SCTP_CID_ASCONF:
1083 if (have_auth || sctp_addip_noauth)
1084 asoc = __sctp_rcv_asconf_lookup(ch, laddr,
1085 sctp_hdr(skb)->source,
1086 transportp);
1087 default:
1088 break;
1089 }
1090
1091 if (asoc)
1092 break;
1093
1094 ch = (sctp_chunkhdr_t *) ch_end;
1095 chunk_num++;
1096 } while (ch_end < skb_tail_pointer(skb));
1097
1098 return asoc;
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001099}
1100
1101/*
1102 * There are circumstances when we need to look inside the SCTP packet
1103 * for information to help us find the association. Examples
1104 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1105 * chunks.
1106 */
1107static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb,
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001108 const union sctp_addr *laddr,
1109 struct sctp_transport **transportp)
1110{
1111 sctp_chunkhdr_t *ch;
1112
1113 ch = (sctp_chunkhdr_t *) skb->data;
1114
Vlad Yasevichdf218572007-12-20 14:10:38 -08001115 /* The code below will attempt to walk the chunk and extract
1116 * parameter information. Before we do that, we need to verify
1117 * that the chunk length doesn't cause overflow. Otherwise, we'll
1118 * walk off the end.
1119 */
1120 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
1121 return NULL;
1122
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001123 /* If this is INIT/INIT-ACK look inside the chunk too. */
1124 switch (ch->type) {
1125 case SCTP_CID_INIT:
1126 case SCTP_CID_INIT_ACK:
1127 return __sctp_rcv_init_lookup(skb, laddr, transportp);
1128 break;
1129
Vlad Yasevichdf218572007-12-20 14:10:38 -08001130 default:
1131 return __sctp_rcv_walk_lookup(skb, laddr, transportp);
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001132 break;
1133 }
1134
Vlad Yasevichdf218572007-12-20 14:10:38 -08001135
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001136 return NULL;
1137}
1138
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139/* Lookup an association for an inbound skb. */
1140static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
1141 const union sctp_addr *paddr,
1142 const union sctp_addr *laddr,
1143 struct sctp_transport **transportp)
1144{
1145 struct sctp_association *asoc;
1146
1147 asoc = __sctp_lookup_association(laddr, paddr, transportp);
1148
1149 /* Further lookup for INIT/INIT-ACK packets.
1150 * SCTP Implementors Guide, 2.18 Handling of address
1151 * parameters within the INIT or INIT-ACK.
1152 */
1153 if (!asoc)
Vlad Yasevichdf218572007-12-20 14:10:38 -08001154 asoc = __sctp_rcv_lookup_harder(skb, laddr, transportp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155
1156 return asoc;
1157}