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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 */
56#include <net/ip.h>
57#include <net/icmp.h>
58#include <net/snmp.h>
59#include <net/sock.h>
60#include <net/xfrm.h>
61#include <net/sctp/sctp.h>
62#include <net/sctp/sm.h>
Vlad Yasevich9ad09772007-12-16 14:06:41 -080063#include <net/sctp/checksum.h>
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -070064#include <net/net_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66/* Forward declarations for internal helpers. */
67static int sctp_rcv_ootb(struct sk_buff *);
68static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
69 const union sctp_addr *laddr,
70 const union sctp_addr *paddr,
71 struct sctp_transport **transportp);
72static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr);
73static struct sctp_association *__sctp_lookup_association(
74 const union sctp_addr *local,
75 const union sctp_addr *peer,
76 struct sctp_transport **pt);
77
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -070078static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
79
Linus Torvalds1da177e2005-04-16 15:20:36 -070080
81/* Calculate the SCTP checksum of an SCTP packet. */
82static inline int sctp_rcv_checksum(struct sk_buff *skb)
83{
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -030084 struct sctphdr *sh = sctp_hdr(skb);
Vlad Yasevich4458f042009-02-13 08:33:42 +000085 __le32 cmp = sh->checksum;
David S. Miller1b003be2009-06-09 00:22:35 -070086 struct sk_buff *list;
Vlad Yasevich4458f042009-02-13 08:33:42 +000087 __le32 val;
88 __u32 tmp = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -070089
David S. Miller1b003be2009-06-09 00:22:35 -070090 skb_walk_frags(skb, list)
Vlad Yasevich4458f042009-02-13 08:33:42 +000091 tmp = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
92 tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Vlad Yasevich4458f042009-02-13 08:33:42 +000094 val = sctp_end_cksum(tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
96 if (val != cmp) {
97 /* CRC failure, dump it. */
98 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS);
99 return -1;
100 }
101 return 0;
102}
103
David S. Miller79af02c2005-07-08 21:47:49 -0700104struct sctp_input_cb {
105 union {
106 struct inet_skb_parm h4;
107#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
108 struct inet6_skb_parm h6;
109#endif
110 } header;
111 struct sctp_chunk *chunk;
112};
113#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
114
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115/*
116 * This is the routine which IP calls when receiving an SCTP packet.
117 */
118int sctp_rcv(struct sk_buff *skb)
119{
120 struct sock *sk;
121 struct sctp_association *asoc;
122 struct sctp_endpoint *ep = NULL;
123 struct sctp_ep_common *rcvr;
124 struct sctp_transport *transport = NULL;
125 struct sctp_chunk *chunk;
126 struct sctphdr *sh;
127 union sctp_addr src;
128 union sctp_addr dest;
129 int family;
130 struct sctp_af *af;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
132 if (skb->pkt_type!=PACKET_HOST)
133 goto discard_it;
134
135 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS);
136
Herbert Xu28cd7752006-10-29 23:46:42 -0800137 if (skb_linearize(skb))
138 goto discard_it;
139
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -0300140 sh = sctp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
142 /* Pull up the IP and SCTP headers. */
Arnaldo Carvalho de Meloea2ae172007-04-25 17:55:53 -0700143 __skb_pull(skb, skb_transport_offset(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 if (skb->len < sizeof(struct sctphdr))
145 goto discard_it;
Lucas Nussbaum06e86802009-02-13 08:33:41 +0000146 if (!sctp_checksum_disable && !skb_csum_unnecessary(skb) &&
147 sctp_rcv_checksum(skb) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 goto discard_it;
149
150 skb_pull(skb, sizeof(struct sctphdr));
151
152 /* Make sure we at least have chunk headers worth of data left. */
153 if (skb->len < sizeof(struct sctp_chunkhdr))
154 goto discard_it;
155
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700156 family = ipver2af(ip_hdr(skb)->version);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 af = sctp_get_af_specific(family);
158 if (unlikely(!af))
159 goto discard_it;
160
161 /* Initialize local addresses for lookups. */
162 af->from_skb(&src, skb, 1);
163 af->from_skb(&dest, skb, 0);
164
165 /* If the packet is to or from a non-unicast address,
166 * silently discard the packet.
167 *
168 * This is not clearly defined in the RFC except in section
169 * 8.4 - OOTB handling. However, based on the book "Stream Control
170 * Transmission Protocol" 2.1, "It is important to note that the
171 * IP address of an SCTP transport address must be a routable
172 * unicast address. In other words, IP multicast addresses and
173 * IP broadcast addresses cannot be used in an SCTP transport
174 * address."
175 */
Vlad Yasevich5636bef2006-06-17 22:55:35 -0700176 if (!af->addr_valid(&src, NULL, skb) ||
177 !af->addr_valid(&dest, NULL, skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 goto discard_it;
179
Al Virod55c41b2006-11-20 17:09:40 -0800180 asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport);
Al Viro1c7d1fc2006-11-20 17:08:09 -0800181
Neil Horman0fd9a652005-06-13 15:11:24 -0700182 if (!asoc)
Al Virod55c41b2006-11-20 17:09:40 -0800183 ep = __sctp_rcv_lookup_endpoint(&dest);
Neil Horman0fd9a652005-06-13 15:11:24 -0700184
185 /* Retrieve the common input handling substructure. */
186 rcvr = asoc ? &asoc->base : &ep->base;
187 sk = rcvr->sk;
188
189 /*
190 * If a frame arrives on an interface and the receiving socket is
191 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
192 */
193 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb)))
194 {
Neil Horman0fd9a652005-06-13 15:11:24 -0700195 if (asoc) {
196 sctp_association_put(asoc);
197 asoc = NULL;
198 } else {
199 sctp_endpoint_put(ep);
200 ep = NULL;
201 }
202 sk = sctp_get_ctl_sock();
203 ep = sctp_sk(sk)->ep;
204 sctp_endpoint_hold(ep);
Neil Horman0fd9a652005-06-13 15:11:24 -0700205 rcvr = &ep->base;
206 }
207
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 /*
209 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
210 * An SCTP packet is called an "out of the blue" (OOTB)
211 * packet if it is correctly formed, i.e., passed the
212 * receiver's checksum check, but the receiver is not
213 * able to identify the association to which this
214 * packet belongs.
215 */
216 if (!asoc) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 if (sctp_rcv_ootb(skb)) {
218 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES);
219 goto discard_release;
220 }
221 }
222
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
224 goto discard_release;
Patrick McHardyb59c2702006-01-06 23:06:10 -0800225 nf_reset(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
Dmitry Mishinfda9ef52006-08-31 15:28:39 -0700227 if (sk_filter(sk, skb))
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900228 goto discard_release;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
230 /* Create an SCTP packet structure. */
231 chunk = sctp_chunkify(skb, asoc, sk);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800232 if (!chunk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233 goto discard_release;
David S. Miller79af02c2005-07-08 21:47:49 -0700234 SCTP_INPUT_CB(skb)->chunk = chunk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 /* Remember what endpoint is to handle this packet. */
237 chunk->rcvr = rcvr;
238
239 /* Remember the SCTP header. */
240 chunk->sctp_hdr = sh;
241
242 /* Set the source and destination addresses of the incoming chunk. */
Al Virod55c41b2006-11-20 17:09:40 -0800243 sctp_init_addrs(chunk, &src, &dest);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
245 /* Remember where we came from. */
246 chunk->transport = transport;
247
248 /* Acquire access to the sock lock. Note: We are safe from other
249 * bottom halves on this lock, but a user may be in the lock too,
250 * so check if it is busy.
251 */
252 sctp_bh_lock_sock(sk);
253
Vlad Yasevichae53b5b2009-01-22 14:53:23 -0800254 if (sk != rcvr->sk) {
255 /* Our cached sk is different from the rcvr->sk. This is
256 * because migrate()/accept() may have moved the association
257 * to a new socket and released all the sockets. So now we
258 * are holding a lock on the old socket while the user may
259 * be doing something with the new socket. Switch our veiw
260 * of the current sk.
261 */
262 sctp_bh_unlock_sock(sk);
263 sk = rcvr->sk;
264 sctp_bh_lock_sock(sk);
265 }
266
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700267 if (sock_owned_by_user(sk)) {
268 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700269 sctp_add_backlog(sk, skb);
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700270 } else {
271 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700272 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700273 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 sctp_bh_unlock_sock(sk);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700276
277 /* Release the asoc/ep ref we took in the lookup calls. */
278 if (asoc)
279 sctp_association_put(asoc);
280 else
281 sctp_endpoint_put(ep);
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800282
Herbert Xu2babf9d2006-03-25 01:25:29 -0800283 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284
285discard_it:
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700286 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 kfree_skb(skb);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800288 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289
290discard_release:
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700291 /* Release the asoc/ep ref we took in the lookup calls. */
Neil Horman0fd9a652005-06-13 15:11:24 -0700292 if (asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 sctp_association_put(asoc);
Neil Horman0fd9a652005-06-13 15:11:24 -0700294 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 sctp_endpoint_put(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296
297 goto discard_it;
298}
299
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700300/* Process the backlog queue of the socket. Every skb on
301 * the backlog holds a ref on an association or endpoint.
302 * We hold this ref throughout the state machine to make
303 * sure that the structure we need is still around.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 */
305int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
306{
David S. Miller79af02c2005-07-08 21:47:49 -0700307 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900308 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
309 struct sctp_ep_common *rcvr = NULL;
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700310 int backloged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900312 rcvr = chunk->rcvr;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800313
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700314 /* If the rcvr is dead then the association or endpoint
315 * has been deleted and we can safely drop the chunk
316 * and refs that we are holding.
317 */
318 if (rcvr->dead) {
319 sctp_chunk_free(chunk);
320 goto done;
321 }
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800322
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700323 if (unlikely(rcvr->sk != sk)) {
324 /* In this case, the association moved from one socket to
325 * another. We are currently sitting on the backlog of the
326 * old socket, so we need to move.
327 * However, since we are here in the process context we
328 * need to take make sure that the user doesn't own
329 * the new socket when we process the packet.
330 * If the new socket is user-owned, queue the chunk to the
331 * backlog of the new socket without dropping any refs.
332 * Otherwise, we can safely push the chunk on the inqueue.
333 */
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800334
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700335 sk = rcvr->sk;
336 sctp_bh_lock_sock(sk);
337
338 if (sock_owned_by_user(sk)) {
339 sk_add_backlog(sk, skb);
340 backloged = 1;
341 } else
342 sctp_inq_push(inqueue, chunk);
343
344 sctp_bh_unlock_sock(sk);
345
346 /* If the chunk was backloged again, don't drop refs */
347 if (backloged)
348 return 0;
349 } else {
350 sctp_inq_push(inqueue, chunk);
351 }
352
353done:
354 /* Release the refs we took in sctp_add_backlog */
355 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
356 sctp_association_put(sctp_assoc(rcvr));
357 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
358 sctp_endpoint_put(sctp_ep(rcvr));
359 else
360 BUG();
361
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900362 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363}
364
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700365static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800366{
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700367 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
368 struct sctp_ep_common *rcvr = chunk->rcvr;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800369
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700370 /* Hold the assoc/ep while hanging on the backlog queue.
371 * This way, we know structures we need will not disappear from us
372 */
373 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
374 sctp_association_hold(sctp_assoc(rcvr));
375 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
376 sctp_endpoint_hold(sctp_ep(rcvr));
377 else
378 BUG();
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800379
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700380 sk_add_backlog(sk, skb);
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800381}
382
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383/* Handle icmp frag needed error. */
384void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
385 struct sctp_transport *t, __u32 pmtu)
386{
Wei Yongjun91bd6b12008-10-23 00:59:52 -0700387 if (!t || (t->pathmtu <= pmtu))
Frank Filz52ccb8e2005-12-22 11:36:46 -0800388 return;
389
Vlad Yasevich8a479492007-06-07 14:21:05 -0400390 if (sock_owned_by_user(sk)) {
391 asoc->pmtu_pending = 1;
392 t->pmtu_pending = 1;
393 return;
394 }
395
Frank Filz52ccb8e2005-12-22 11:36:46 -0800396 if (t->param_flags & SPP_PMTUD_ENABLE) {
Vlad Yasevichc910b472007-06-07 13:47:03 -0400397 /* Update transports view of the MTU */
398 sctp_transport_update_pmtu(t, pmtu);
Frank Filz52ccb8e2005-12-22 11:36:46 -0800399
400 /* Update association pmtu. */
401 sctp_assoc_sync_pmtu(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402 }
403
Frank Filz52ccb8e2005-12-22 11:36:46 -0800404 /* Retransmit with the new pmtu setting.
405 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
406 * Needed will never be sent, but if a message was sent before
407 * PMTU discovery was disabled that was larger than the PMTU, it
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900408 * would not be fragmented, so it must be re-transmitted fragmented.
Frank Filz52ccb8e2005-12-22 11:36:46 -0800409 */
410 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411}
412
413/*
414 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
415 *
416 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
417 * or a "Protocol Unreachable" treat this message as an abort
418 * with the T bit set.
419 *
420 * This function sends an event to the state machine, which will abort the
421 * association.
422 *
423 */
424void sctp_icmp_proto_unreachable(struct sock *sk,
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900425 struct sctp_association *asoc,
426 struct sctp_transport *t)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427{
Harvey Harrison0dc47872008-03-05 20:47:47 -0800428 SCTP_DEBUG_PRINTK("%s\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429
430 sctp_do_sm(SCTP_EVENT_T_OTHER,
431 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
Frank Filz3f7a87d2005-06-20 13:14:57 -0700432 asoc->state, asoc->ep, asoc, t,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 GFP_ATOMIC);
434
435}
436
437/* Common lookup code for icmp/icmpv6 error handler. */
438struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
439 struct sctphdr *sctphdr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 struct sctp_association **app,
441 struct sctp_transport **tpp)
442{
443 union sctp_addr saddr;
444 union sctp_addr daddr;
445 struct sctp_af *af;
446 struct sock *sk = NULL;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700447 struct sctp_association *asoc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 struct sctp_transport *transport = NULL;
Wei Yongjun7115e632008-06-19 16:07:48 -0700449 struct sctp_init_chunk *chunkhdr;
450 __u32 vtag = ntohl(sctphdr->vtag);
451 int len = skb->len - ((void *)sctphdr - (void *)skb->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700453 *app = NULL; *tpp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454
455 af = sctp_get_af_specific(family);
456 if (unlikely(!af)) {
457 return NULL;
458 }
459
460 /* Initialize local addresses for lookups. */
461 af->from_skb(&saddr, skb, 1);
462 af->from_skb(&daddr, skb, 0);
463
464 /* Look for an association that matches the incoming ICMP error
465 * packet.
466 */
Al Virod55c41b2006-11-20 17:09:40 -0800467 asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700468 if (!asoc)
469 return NULL;
470
471 sk = asoc->base.sk;
472
Wei Yongjun7115e632008-06-19 16:07:48 -0700473 /* RFC 4960, Appendix C. ICMP Handling
474 *
475 * ICMP6) An implementation MUST validate that the Verification Tag
476 * contained in the ICMP message matches the Verification Tag of
477 * the peer. If the Verification Tag is not 0 and does NOT
478 * match, discard the ICMP message. If it is 0 and the ICMP
479 * message contains enough bytes to verify that the chunk type is
480 * an INIT chunk and that the Initiate Tag matches the tag of the
481 * peer, continue with ICMP7. If the ICMP message is too short
482 * or the chunk type or the Initiate Tag does not match, silently
483 * discard the packet.
484 */
485 if (vtag == 0) {
486 chunkhdr = (struct sctp_init_chunk *)((void *)sctphdr
487 + sizeof(struct sctphdr));
488 if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
489 + sizeof(__be32) ||
490 chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
491 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) {
492 goto out;
493 }
494 } else if (vtag != asoc->c.peer_vtag) {
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700495 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 }
497
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 sctp_bh_lock_sock(sk);
499
500 /* If too many ICMPs get dropped on busy
501 * servers this needs to be solved differently.
502 */
503 if (sock_owned_by_user(sk))
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700504 NET_INC_STATS_BH(&init_net, LINUX_MIB_LOCKDROPPEDICMPS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 *app = asoc;
507 *tpp = transport;
508 return sk;
509
510out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 if (asoc)
512 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 return NULL;
514}
515
516/* Common cleanup code for icmp/icmpv6 error handler. */
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700517void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518{
519 sctp_bh_unlock_sock(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 if (asoc)
521 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522}
523
524/*
525 * This routine is called by the ICMP module when it gets some
526 * sort of error condition. If err < 0 then the socket should
527 * be closed and the error returned to the user. If err > 0
528 * it's just the icmp type << 8 | icmp code. After adjustment
529 * header points to the first 8 bytes of the sctp header. We need
530 * to find the appropriate port.
531 *
532 * The locking strategy used here is very "optimistic". When
533 * someone else accesses the socket the ICMP is just dropped
534 * and for some paths there is no check at all.
535 * A more general error queue to queue errors for later handling
536 * is probably better.
537 *
538 */
539void sctp_v4_err(struct sk_buff *skb, __u32 info)
540{
541 struct iphdr *iph = (struct iphdr *)skb->data;
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300542 const int ihlen = iph->ihl * 4;
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300543 const int type = icmp_hdr(skb)->type;
544 const int code = icmp_hdr(skb)->code;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 struct sock *sk;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700546 struct sctp_association *asoc = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547 struct sctp_transport *transport;
548 struct inet_sock *inet;
Arnaldo Carvalho de Melo2e07fa92007-04-10 21:22:35 -0700549 sk_buff_data_t saveip, savesctp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 int err;
551
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300552 if (skb->len < ihlen + 8) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700553 ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 return;
555 }
556
557 /* Fix up skb to look at the embedded net header. */
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700558 saveip = skb->network_header;
559 savesctp = skb->transport_header;
Arnaldo Carvalho de Melo31c77112007-03-10 19:04:55 -0300560 skb_reset_network_header(skb);
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300561 skb_set_transport_header(skb, ihlen);
562 sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
Arnaldo Carvalho de Melo2e07fa92007-04-10 21:22:35 -0700563 /* Put back, the original values. */
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700564 skb->network_header = saveip;
565 skb->transport_header = savesctp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 if (!sk) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700567 ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 return;
569 }
570 /* Warning: The sock lock is held. Remember to call
571 * sctp_err_finish!
572 */
573
574 switch (type) {
575 case ICMP_PARAMETERPROB:
576 err = EPROTO;
577 break;
578 case ICMP_DEST_UNREACH:
579 if (code > NR_ICMP_UNREACH)
580 goto out_unlock;
581
582 /* PMTU discovery (RFC1191) */
583 if (ICMP_FRAG_NEEDED == code) {
584 sctp_icmp_frag_needed(sk, asoc, transport, info);
585 goto out_unlock;
586 }
587 else {
588 if (ICMP_PROT_UNREACH == code) {
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700589 sctp_icmp_proto_unreachable(sk, asoc,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 transport);
591 goto out_unlock;
592 }
593 }
594 err = icmp_err_convert[code].errno;
595 break;
596 case ICMP_TIME_EXCEEDED:
597 /* Ignore any time exceeded errors due to fragment reassembly
598 * timeouts.
599 */
600 if (ICMP_EXC_FRAGTIME == code)
601 goto out_unlock;
602
603 err = EHOSTUNREACH;
604 break;
605 default:
606 goto out_unlock;
607 }
608
609 inet = inet_sk(sk);
610 if (!sock_owned_by_user(sk) && inet->recverr) {
611 sk->sk_err = err;
612 sk->sk_error_report(sk);
613 } else { /* Only an error on timeout */
614 sk->sk_err_soft = err;
615 }
616
617out_unlock:
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700618 sctp_err_finish(sk, asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619}
620
621/*
622 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
623 *
624 * This function scans all the chunks in the OOTB packet to determine if
625 * the packet should be discarded right away. If a response might be needed
626 * for this packet, or, if further processing is possible, the packet will
627 * be queued to a proper inqueue for the next phase of handling.
628 *
629 * Output:
630 * Return 0 - If further processing is needed.
631 * Return 1 - If the packet can be discarded right away.
632 */
sebastian@breakpoint.cc04675212007-07-26 23:21:31 +0200633static int sctp_rcv_ootb(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634{
635 sctp_chunkhdr_t *ch;
636 __u8 *ch_end;
637 sctp_errhdr_t *err;
638
639 ch = (sctp_chunkhdr_t *) skb->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640
641 /* Scan through all the chunks in the packet. */
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800642 do {
643 /* Break out if chunk length is less then minimal. */
644 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
645 break;
646
647 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700648 if (ch_end > skb_tail_pointer(skb))
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800649 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650
651 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
652 * receiver MUST silently discard the OOTB packet and take no
653 * further action.
654 */
655 if (SCTP_CID_ABORT == ch->type)
656 goto discard;
657
658 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
659 * chunk, the receiver should silently discard the packet
660 * and take no further action.
661 */
662 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
663 goto discard;
664
Vlad Yasevich3c77f962007-09-17 15:14:28 -0400665 /* RFC 4460, 2.11.2
666 * This will discard packets with INIT chunk bundled as
667 * subsequent chunks in the packet. When INIT is first,
668 * the normal INIT processing will discard the chunk.
669 */
670 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
671 goto discard;
672
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
674 * or a COOKIE ACK the SCTP Packet should be silently
675 * discarded.
676 */
677 if (SCTP_CID_COOKIE_ACK == ch->type)
678 goto discard;
679
680 if (SCTP_CID_ERROR == ch->type) {
681 sctp_walk_errors(err, ch) {
682 if (SCTP_ERROR_STALE_COOKIE == err->cause)
683 goto discard;
684 }
685 }
686
687 ch = (sctp_chunkhdr_t *) ch_end;
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700688 } while (ch_end < skb_tail_pointer(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689
690 return 0;
691
692discard:
693 return 1;
694}
695
696/* Insert endpoint into the hash table. */
697static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
698{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 struct sctp_ep_common *epb;
700 struct sctp_hashbucket *head;
701
702 epb = &ep->base;
703
704 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
705 head = &sctp_ep_hashtable[epb->hashent];
706
707 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500708 hlist_add_head(&epb->node, &head->chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 sctp_write_unlock(&head->lock);
710}
711
712/* Add an endpoint to the hash. Local BH-safe. */
713void sctp_hash_endpoint(struct sctp_endpoint *ep)
714{
715 sctp_local_bh_disable();
716 __sctp_hash_endpoint(ep);
717 sctp_local_bh_enable();
718}
719
720/* Remove endpoint from the hash table. */
721static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
722{
723 struct sctp_hashbucket *head;
724 struct sctp_ep_common *epb;
725
726 epb = &ep->base;
727
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500728 if (hlist_unhashed(&epb->node))
729 return;
730
Linus Torvalds1da177e2005-04-16 15:20:36 -0700731 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
732
733 head = &sctp_ep_hashtable[epb->hashent];
734
735 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500736 __hlist_del(&epb->node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 sctp_write_unlock(&head->lock);
738}
739
740/* Remove endpoint from the hash. Local BH-safe. */
741void sctp_unhash_endpoint(struct sctp_endpoint *ep)
742{
743 sctp_local_bh_disable();
744 __sctp_unhash_endpoint(ep);
745 sctp_local_bh_enable();
746}
747
748/* Look up an endpoint. */
749static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr)
750{
751 struct sctp_hashbucket *head;
752 struct sctp_ep_common *epb;
753 struct sctp_endpoint *ep;
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500754 struct hlist_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 int hash;
756
Al Viro1c7d1fc2006-11-20 17:08:09 -0800757 hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 head = &sctp_ep_hashtable[hash];
759 read_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500760 sctp_for_each_hentry(epb, node, &head->chain) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 ep = sctp_ep(epb);
762 if (sctp_endpoint_is_match(ep, laddr))
763 goto hit;
764 }
765
766 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767
768hit:
769 sctp_endpoint_hold(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 read_unlock(&head->lock);
771 return ep;
772}
773
774/* Insert association into the hash table. */
775static void __sctp_hash_established(struct sctp_association *asoc)
776{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 struct sctp_ep_common *epb;
778 struct sctp_hashbucket *head;
779
780 epb = &asoc->base;
781
782 /* Calculate which chain this entry will belong to. */
783 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port);
784
785 head = &sctp_assoc_hashtable[epb->hashent];
786
787 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500788 hlist_add_head(&epb->node, &head->chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 sctp_write_unlock(&head->lock);
790}
791
792/* Add an association to the hash. Local BH-safe. */
793void sctp_hash_established(struct sctp_association *asoc)
794{
Vlad Yasevichde76e692006-10-30 18:55:11 -0800795 if (asoc->temp)
796 return;
797
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 sctp_local_bh_disable();
799 __sctp_hash_established(asoc);
800 sctp_local_bh_enable();
801}
802
803/* Remove association from the hash table. */
804static void __sctp_unhash_established(struct sctp_association *asoc)
805{
806 struct sctp_hashbucket *head;
807 struct sctp_ep_common *epb;
808
809 epb = &asoc->base;
810
811 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port,
812 asoc->peer.port);
813
814 head = &sctp_assoc_hashtable[epb->hashent];
815
816 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500817 __hlist_del(&epb->node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 sctp_write_unlock(&head->lock);
819}
820
821/* Remove association from the hash table. Local BH-safe. */
822void sctp_unhash_established(struct sctp_association *asoc)
823{
Vlad Yasevichde76e692006-10-30 18:55:11 -0800824 if (asoc->temp)
825 return;
826
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 sctp_local_bh_disable();
828 __sctp_unhash_established(asoc);
829 sctp_local_bh_enable();
830}
831
832/* Look up an association. */
833static struct sctp_association *__sctp_lookup_association(
834 const union sctp_addr *local,
835 const union sctp_addr *peer,
836 struct sctp_transport **pt)
837{
838 struct sctp_hashbucket *head;
839 struct sctp_ep_common *epb;
840 struct sctp_association *asoc;
841 struct sctp_transport *transport;
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500842 struct hlist_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 int hash;
844
845 /* Optimize here for direct hit, only listening connections can
846 * have wildcards anyways.
847 */
Al Viroe2fcced2006-11-20 17:08:41 -0800848 hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 head = &sctp_assoc_hashtable[hash];
850 read_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500851 sctp_for_each_hentry(epb, node, &head->chain) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 asoc = sctp_assoc(epb);
853 transport = sctp_assoc_is_match(asoc, local, peer);
854 if (transport)
855 goto hit;
856 }
857
858 read_unlock(&head->lock);
859
860 return NULL;
861
862hit:
863 *pt = transport;
864 sctp_association_hold(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 read_unlock(&head->lock);
866 return asoc;
867}
868
869/* Look up an association. BH-safe. */
870SCTP_STATIC
871struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr,
872 const union sctp_addr *paddr,
873 struct sctp_transport **transportp)
874{
875 struct sctp_association *asoc;
876
877 sctp_local_bh_disable();
878 asoc = __sctp_lookup_association(laddr, paddr, transportp);
879 sctp_local_bh_enable();
880
881 return asoc;
882}
883
884/* Is there an association matching the given local and peer addresses? */
885int sctp_has_association(const union sctp_addr *laddr,
886 const union sctp_addr *paddr)
887{
888 struct sctp_association *asoc;
889 struct sctp_transport *transport;
890
Al Viro6c7be552006-11-20 17:11:50 -0800891 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 sctp_association_put(asoc);
893 return 1;
894 }
895
896 return 0;
897}
898
899/*
900 * SCTP Implementors Guide, 2.18 Handling of address
901 * parameters within the INIT or INIT-ACK.
902 *
903 * D) When searching for a matching TCB upon reception of an INIT
904 * or INIT-ACK chunk the receiver SHOULD use not only the
905 * source address of the packet (containing the INIT or
906 * INIT-ACK) but the receiver SHOULD also use all valid
907 * address parameters contained within the chunk.
908 *
909 * 2.18.3 Solution description
910 *
911 * This new text clearly specifies to an implementor the need
912 * to look within the INIT or INIT-ACK. Any implementation that
913 * does not do this, may not be able to establish associations
914 * in certain circumstances.
915 *
916 */
917static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
918 const union sctp_addr *laddr, struct sctp_transport **transportp)
919{
920 struct sctp_association *asoc;
921 union sctp_addr addr;
922 union sctp_addr *paddr = &addr;
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -0300923 struct sctphdr *sh = sctp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 sctp_chunkhdr_t *ch;
925 union sctp_params params;
926 sctp_init_chunk_t *init;
927 struct sctp_transport *transport;
928 struct sctp_af *af;
929
930 ch = (sctp_chunkhdr_t *) skb->data;
931
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 /*
933 * This code will NOT touch anything inside the chunk--it is
934 * strictly READ-ONLY.
935 *
936 * RFC 2960 3 SCTP packet Format
937 *
938 * Multiple chunks can be bundled into one SCTP packet up to
939 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
940 * COMPLETE chunks. These chunks MUST NOT be bundled with any
941 * other chunk in a packet. See Section 6.10 for more details
942 * on chunk bundling.
943 */
944
945 /* Find the start of the TLVs and the end of the chunk. This is
946 * the region we search for address parameters.
947 */
948 init = (sctp_init_chunk_t *)skb->data;
949
950 /* Walk the parameters looking for embedded addresses. */
951 sctp_walk_params(params, init, init_hdr.params) {
952
953 /* Note: Ignoring hostname addresses. */
954 af = sctp_get_af_specific(param_type2af(params.p->type));
955 if (!af)
956 continue;
957
Al Virodd86d132006-11-20 17:11:13 -0800958 af->from_addr_param(paddr, params.addr, sh->source, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959
Al Virodd86d132006-11-20 17:11:13 -0800960 asoc = __sctp_lookup_association(laddr, paddr, &transport);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 if (asoc)
962 return asoc;
963 }
964
965 return NULL;
966}
967
Vlad Yasevichdf218572007-12-20 14:10:38 -0800968/* ADD-IP, Section 5.2
969 * When an endpoint receives an ASCONF Chunk from the remote peer
970 * special procedures may be needed to identify the association the
971 * ASCONF Chunk is associated with. To properly find the association
972 * the following procedures SHOULD be followed:
973 *
974 * D2) If the association is not found, use the address found in the
975 * Address Parameter TLV combined with the port number found in the
976 * SCTP common header. If found proceed to rule D4.
977 *
978 * D2-ext) If more than one ASCONF Chunks are packed together, use the
979 * address found in the ASCONF Address Parameter TLV of each of the
980 * subsequent ASCONF Chunks. If found, proceed to rule D4.
981 */
982static struct sctp_association *__sctp_rcv_asconf_lookup(
983 sctp_chunkhdr_t *ch,
984 const union sctp_addr *laddr,
Al Virobc92dd12008-03-17 22:47:32 -0700985 __be16 peer_port,
Vlad Yasevichdf218572007-12-20 14:10:38 -0800986 struct sctp_transport **transportp)
987{
988 sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch;
989 struct sctp_af *af;
990 union sctp_addr_param *param;
991 union sctp_addr paddr;
992
993 /* Skip over the ADDIP header and find the Address parameter */
994 param = (union sctp_addr_param *)(asconf + 1);
995
996 af = sctp_get_af_specific(param_type2af(param->v4.param_hdr.type));
997 if (unlikely(!af))
998 return NULL;
999
1000 af->from_addr_param(&paddr, param, peer_port, 0);
1001
1002 return __sctp_lookup_association(laddr, &paddr, transportp);
1003}
1004
1005
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001006/* SCTP-AUTH, Section 6.3:
1007* If the receiver does not find a STCB for a packet containing an AUTH
1008* chunk as the first chunk and not a COOKIE-ECHO chunk as the second
1009* chunk, it MUST use the chunks after the AUTH chunk to look up an existing
1010* association.
1011*
1012* This means that any chunks that can help us identify the association need
1013* to be looked at to find this assocation.
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001014*/
Vlad Yasevichdf218572007-12-20 14:10:38 -08001015static struct sctp_association *__sctp_rcv_walk_lookup(struct sk_buff *skb,
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001016 const union sctp_addr *laddr,
1017 struct sctp_transport **transportp)
1018{
Vlad Yasevichdf218572007-12-20 14:10:38 -08001019 struct sctp_association *asoc = NULL;
1020 sctp_chunkhdr_t *ch;
1021 int have_auth = 0;
1022 unsigned int chunk_num = 1;
1023 __u8 *ch_end;
1024
1025 /* Walk through the chunks looking for AUTH or ASCONF chunks
1026 * to help us find the association.
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001027 */
Vlad Yasevichdf218572007-12-20 14:10:38 -08001028 ch = (sctp_chunkhdr_t *) skb->data;
1029 do {
1030 /* Break out if chunk length is less then minimal. */
1031 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
1032 break;
1033
1034 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
1035 if (ch_end > skb_tail_pointer(skb))
1036 break;
1037
1038 switch(ch->type) {
1039 case SCTP_CID_AUTH:
1040 have_auth = chunk_num;
1041 break;
1042
1043 case SCTP_CID_COOKIE_ECHO:
1044 /* If a packet arrives containing an AUTH chunk as
1045 * a first chunk, a COOKIE-ECHO chunk as the second
1046 * chunk, and possibly more chunks after them, and
1047 * the receiver does not have an STCB for that
1048 * packet, then authentication is based on
1049 * the contents of the COOKIE- ECHO chunk.
1050 */
1051 if (have_auth == 1 && chunk_num == 2)
1052 return NULL;
1053 break;
1054
1055 case SCTP_CID_ASCONF:
1056 if (have_auth || sctp_addip_noauth)
1057 asoc = __sctp_rcv_asconf_lookup(ch, laddr,
1058 sctp_hdr(skb)->source,
1059 transportp);
1060 default:
1061 break;
1062 }
1063
1064 if (asoc)
1065 break;
1066
1067 ch = (sctp_chunkhdr_t *) ch_end;
1068 chunk_num++;
1069 } while (ch_end < skb_tail_pointer(skb));
1070
1071 return asoc;
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001072}
1073
1074/*
1075 * There are circumstances when we need to look inside the SCTP packet
1076 * for information to help us find the association. Examples
1077 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1078 * chunks.
1079 */
1080static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb,
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001081 const union sctp_addr *laddr,
1082 struct sctp_transport **transportp)
1083{
1084 sctp_chunkhdr_t *ch;
1085
1086 ch = (sctp_chunkhdr_t *) skb->data;
1087
Vlad Yasevichdf218572007-12-20 14:10:38 -08001088 /* The code below will attempt to walk the chunk and extract
1089 * parameter information. Before we do that, we need to verify
1090 * that the chunk length doesn't cause overflow. Otherwise, we'll
1091 * walk off the end.
1092 */
1093 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
1094 return NULL;
1095
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001096 /* If this is INIT/INIT-ACK look inside the chunk too. */
1097 switch (ch->type) {
1098 case SCTP_CID_INIT:
1099 case SCTP_CID_INIT_ACK:
1100 return __sctp_rcv_init_lookup(skb, laddr, transportp);
1101 break;
1102
Vlad Yasevichdf218572007-12-20 14:10:38 -08001103 default:
1104 return __sctp_rcv_walk_lookup(skb, laddr, transportp);
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001105 break;
1106 }
1107
Vlad Yasevichdf218572007-12-20 14:10:38 -08001108
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001109 return NULL;
1110}
1111
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112/* Lookup an association for an inbound skb. */
1113static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
1114 const union sctp_addr *paddr,
1115 const union sctp_addr *laddr,
1116 struct sctp_transport **transportp)
1117{
1118 struct sctp_association *asoc;
1119
1120 asoc = __sctp_lookup_association(laddr, paddr, transportp);
1121
1122 /* Further lookup for INIT/INIT-ACK packets.
1123 * SCTP Implementors Guide, 2.18 Handling of address
1124 * parameters within the INIT or INIT-ACK.
1125 */
1126 if (!asoc)
Vlad Yasevichdf218572007-12-20 14:10:38 -08001127 asoc = __sctp_rcv_lookup_harder(skb, laddr, transportp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128
1129 return asoc;
1130}