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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* SCTP kernel reference Implementation
2 * 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 *
9 * This file is part of the SCTP kernel reference Implementation
10 *
11 * These functions handle all input from the IP layer into SCTP.
12 *
13 * The SCTP reference implementation is free software;
14 * 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 *
19 * The SCTP reference implementation is distributed in the hope that it
20 * 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>
63
64/* Forward declarations for internal helpers. */
65static int sctp_rcv_ootb(struct sk_buff *);
66static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
67 const union sctp_addr *laddr,
68 const union sctp_addr *paddr,
69 struct sctp_transport **transportp);
70static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr);
71static struct sctp_association *__sctp_lookup_association(
72 const union sctp_addr *local,
73 const union sctp_addr *peer,
74 struct sctp_transport **pt);
75
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -070076static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
77
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
79/* Calculate the SCTP checksum of an SCTP packet. */
80static inline int sctp_rcv_checksum(struct sk_buff *skb)
81{
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 struct sk_buff *list = skb_shinfo(skb)->frag_list;
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -030083 struct sctphdr *sh = sctp_hdr(skb);
84 __u32 cmp = ntohl(sh->checksum);
85 __u32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
87 for (; list; list = list->next)
88 val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
89 val);
90
91 val = sctp_end_cksum(val);
92
93 if (val != cmp) {
94 /* CRC failure, dump it. */
95 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS);
96 return -1;
97 }
98 return 0;
99}
100
David S. Miller79af02c2005-07-08 21:47:49 -0700101struct sctp_input_cb {
102 union {
103 struct inet_skb_parm h4;
104#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
105 struct inet6_skb_parm h6;
106#endif
107 } header;
108 struct sctp_chunk *chunk;
109};
110#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
111
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112/*
113 * This is the routine which IP calls when receiving an SCTP packet.
114 */
115int sctp_rcv(struct sk_buff *skb)
116{
117 struct sock *sk;
118 struct sctp_association *asoc;
119 struct sctp_endpoint *ep = NULL;
120 struct sctp_ep_common *rcvr;
121 struct sctp_transport *transport = NULL;
122 struct sctp_chunk *chunk;
123 struct sctphdr *sh;
124 union sctp_addr src;
125 union sctp_addr dest;
126 int family;
127 struct sctp_af *af;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128
129 if (skb->pkt_type!=PACKET_HOST)
130 goto discard_it;
131
132 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS);
133
Herbert Xu28cd7752006-10-29 23:46:42 -0800134 if (skb_linearize(skb))
135 goto discard_it;
136
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -0300137 sh = sctp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138
139 /* Pull up the IP and SCTP headers. */
Arnaldo Carvalho de Meloea2ae172007-04-25 17:55:53 -0700140 __skb_pull(skb, skb_transport_offset(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 if (skb->len < sizeof(struct sctphdr))
142 goto discard_it;
Herbert Xu60476372007-04-09 11:59:39 -0700143 if (!skb_csum_unnecessary(skb) && sctp_rcv_checksum(skb) < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 goto discard_it;
145
146 skb_pull(skb, sizeof(struct sctphdr));
147
148 /* Make sure we at least have chunk headers worth of data left. */
149 if (skb->len < sizeof(struct sctp_chunkhdr))
150 goto discard_it;
151
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700152 family = ipver2af(ip_hdr(skb)->version);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 af = sctp_get_af_specific(family);
154 if (unlikely(!af))
155 goto discard_it;
156
157 /* Initialize local addresses for lookups. */
158 af->from_skb(&src, skb, 1);
159 af->from_skb(&dest, skb, 0);
160
161 /* If the packet is to or from a non-unicast address,
162 * silently discard the packet.
163 *
164 * This is not clearly defined in the RFC except in section
165 * 8.4 - OOTB handling. However, based on the book "Stream Control
166 * Transmission Protocol" 2.1, "It is important to note that the
167 * IP address of an SCTP transport address must be a routable
168 * unicast address. In other words, IP multicast addresses and
169 * IP broadcast addresses cannot be used in an SCTP transport
170 * address."
171 */
Vlad Yasevich5636bef2006-06-17 22:55:35 -0700172 if (!af->addr_valid(&src, NULL, skb) ||
173 !af->addr_valid(&dest, NULL, skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 goto discard_it;
175
Al Virod55c41b2006-11-20 17:09:40 -0800176 asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport);
Al Viro1c7d1fc2006-11-20 17:08:09 -0800177
Neil Horman0fd9a652005-06-13 15:11:24 -0700178 if (!asoc)
Al Virod55c41b2006-11-20 17:09:40 -0800179 ep = __sctp_rcv_lookup_endpoint(&dest);
Neil Horman0fd9a652005-06-13 15:11:24 -0700180
181 /* Retrieve the common input handling substructure. */
182 rcvr = asoc ? &asoc->base : &ep->base;
183 sk = rcvr->sk;
184
185 /*
186 * If a frame arrives on an interface and the receiving socket is
187 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
188 */
189 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb)))
190 {
Neil Horman0fd9a652005-06-13 15:11:24 -0700191 if (asoc) {
192 sctp_association_put(asoc);
193 asoc = NULL;
194 } else {
195 sctp_endpoint_put(ep);
196 ep = NULL;
197 }
198 sk = sctp_get_ctl_sock();
199 ep = sctp_sk(sk)->ep;
200 sctp_endpoint_hold(ep);
Neil Horman0fd9a652005-06-13 15:11:24 -0700201 rcvr = &ep->base;
202 }
203
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 /*
205 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
206 * An SCTP packet is called an "out of the blue" (OOTB)
207 * packet if it is correctly formed, i.e., passed the
208 * receiver's checksum check, but the receiver is not
209 * able to identify the association to which this
210 * packet belongs.
211 */
212 if (!asoc) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213 if (sctp_rcv_ootb(skb)) {
214 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES);
215 goto discard_release;
216 }
217 }
218
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
220 goto discard_release;
Patrick McHardyb59c2702006-01-06 23:06:10 -0800221 nf_reset(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
Dmitry Mishinfda9ef52006-08-31 15:28:39 -0700223 if (sk_filter(sk, skb))
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900224 goto discard_release;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225
226 /* Create an SCTP packet structure. */
227 chunk = sctp_chunkify(skb, asoc, sk);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800228 if (!chunk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 goto discard_release;
David S. Miller79af02c2005-07-08 21:47:49 -0700230 SCTP_INPUT_CB(skb)->chunk = chunk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 /* Remember what endpoint is to handle this packet. */
233 chunk->rcvr = rcvr;
234
235 /* Remember the SCTP header. */
236 chunk->sctp_hdr = sh;
237
238 /* Set the source and destination addresses of the incoming chunk. */
Al Virod55c41b2006-11-20 17:09:40 -0800239 sctp_init_addrs(chunk, &src, &dest);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240
241 /* Remember where we came from. */
242 chunk->transport = transport;
243
244 /* Acquire access to the sock lock. Note: We are safe from other
245 * bottom halves on this lock, but a user may be in the lock too,
246 * so check if it is busy.
247 */
248 sctp_bh_lock_sock(sk);
249
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700250 if (sock_owned_by_user(sk)) {
251 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700252 sctp_add_backlog(sk, skb);
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700253 } else {
254 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700255 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700256 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258 sctp_bh_unlock_sock(sk);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700259
260 /* Release the asoc/ep ref we took in the lookup calls. */
261 if (asoc)
262 sctp_association_put(asoc);
263 else
264 sctp_endpoint_put(ep);
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800265
Herbert Xu2babf9d2006-03-25 01:25:29 -0800266 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
268discard_it:
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700269 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 kfree_skb(skb);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800271 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
273discard_release:
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700274 /* Release the asoc/ep ref we took in the lookup calls. */
Neil Horman0fd9a652005-06-13 15:11:24 -0700275 if (asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 sctp_association_put(asoc);
Neil Horman0fd9a652005-06-13 15:11:24 -0700277 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 sctp_endpoint_put(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
280 goto discard_it;
281}
282
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700283/* Process the backlog queue of the socket. Every skb on
284 * the backlog holds a ref on an association or endpoint.
285 * We hold this ref throughout the state machine to make
286 * sure that the structure we need is still around.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 */
288int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
289{
David S. Miller79af02c2005-07-08 21:47:49 -0700290 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900291 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
292 struct sctp_ep_common *rcvr = NULL;
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700293 int backloged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900295 rcvr = chunk->rcvr;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800296
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700297 /* If the rcvr is dead then the association or endpoint
298 * has been deleted and we can safely drop the chunk
299 * and refs that we are holding.
300 */
301 if (rcvr->dead) {
302 sctp_chunk_free(chunk);
303 goto done;
304 }
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800305
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700306 if (unlikely(rcvr->sk != sk)) {
307 /* In this case, the association moved from one socket to
308 * another. We are currently sitting on the backlog of the
309 * old socket, so we need to move.
310 * However, since we are here in the process context we
311 * need to take make sure that the user doesn't own
312 * the new socket when we process the packet.
313 * If the new socket is user-owned, queue the chunk to the
314 * backlog of the new socket without dropping any refs.
315 * Otherwise, we can safely push the chunk on the inqueue.
316 */
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800317
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700318 sk = rcvr->sk;
319 sctp_bh_lock_sock(sk);
320
321 if (sock_owned_by_user(sk)) {
322 sk_add_backlog(sk, skb);
323 backloged = 1;
324 } else
325 sctp_inq_push(inqueue, chunk);
326
327 sctp_bh_unlock_sock(sk);
328
329 /* If the chunk was backloged again, don't drop refs */
330 if (backloged)
331 return 0;
332 } else {
333 sctp_inq_push(inqueue, chunk);
334 }
335
336done:
337 /* Release the refs we took in sctp_add_backlog */
338 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
339 sctp_association_put(sctp_assoc(rcvr));
340 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
341 sctp_endpoint_put(sctp_ep(rcvr));
342 else
343 BUG();
344
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900345 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346}
347
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700348static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800349{
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700350 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
351 struct sctp_ep_common *rcvr = chunk->rcvr;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800352
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700353 /* Hold the assoc/ep while hanging on the backlog queue.
354 * This way, we know structures we need will not disappear from us
355 */
356 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
357 sctp_association_hold(sctp_assoc(rcvr));
358 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
359 sctp_endpoint_hold(sctp_ep(rcvr));
360 else
361 BUG();
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800362
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700363 sk_add_backlog(sk, skb);
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800364}
365
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366/* Handle icmp frag needed error. */
367void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
368 struct sctp_transport *t, __u32 pmtu)
369{
Vlad Yasevich8a479492007-06-07 14:21:05 -0400370 if (!t || (t->pathmtu == pmtu))
Frank Filz52ccb8e2005-12-22 11:36:46 -0800371 return;
372
Vlad Yasevich8a479492007-06-07 14:21:05 -0400373 if (sock_owned_by_user(sk)) {
374 asoc->pmtu_pending = 1;
375 t->pmtu_pending = 1;
376 return;
377 }
378
Frank Filz52ccb8e2005-12-22 11:36:46 -0800379 if (t->param_flags & SPP_PMTUD_ENABLE) {
Vlad Yasevichc910b472007-06-07 13:47:03 -0400380 /* Update transports view of the MTU */
381 sctp_transport_update_pmtu(t, pmtu);
Frank Filz52ccb8e2005-12-22 11:36:46 -0800382
383 /* Update association pmtu. */
384 sctp_assoc_sync_pmtu(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 }
386
Frank Filz52ccb8e2005-12-22 11:36:46 -0800387 /* Retransmit with the new pmtu setting.
388 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
389 * Needed will never be sent, but if a message was sent before
390 * PMTU discovery was disabled that was larger than the PMTU, it
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900391 * would not be fragmented, so it must be re-transmitted fragmented.
Frank Filz52ccb8e2005-12-22 11:36:46 -0800392 */
393 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394}
395
396/*
397 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
398 *
399 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
400 * or a "Protocol Unreachable" treat this message as an abort
401 * with the T bit set.
402 *
403 * This function sends an event to the state machine, which will abort the
404 * association.
405 *
406 */
407void sctp_icmp_proto_unreachable(struct sock *sk,
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900408 struct sctp_association *asoc,
409 struct sctp_transport *t)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410{
411 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__);
412
413 sctp_do_sm(SCTP_EVENT_T_OTHER,
414 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
Frank Filz3f7a87d2005-06-20 13:14:57 -0700415 asoc->state, asoc->ep, asoc, t,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 GFP_ATOMIC);
417
418}
419
420/* Common lookup code for icmp/icmpv6 error handler. */
421struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
422 struct sctphdr *sctphdr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 struct sctp_association **app,
424 struct sctp_transport **tpp)
425{
426 union sctp_addr saddr;
427 union sctp_addr daddr;
428 struct sctp_af *af;
429 struct sock *sk = NULL;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700430 struct sctp_association *asoc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 struct sctp_transport *transport = NULL;
432
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700433 *app = NULL; *tpp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434
435 af = sctp_get_af_specific(family);
436 if (unlikely(!af)) {
437 return NULL;
438 }
439
440 /* Initialize local addresses for lookups. */
441 af->from_skb(&saddr, skb, 1);
442 af->from_skb(&daddr, skb, 0);
443
444 /* Look for an association that matches the incoming ICMP error
445 * packet.
446 */
Al Virod55c41b2006-11-20 17:09:40 -0800447 asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700448 if (!asoc)
449 return NULL;
450
451 sk = asoc->base.sk;
452
453 if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) {
454 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
455 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 }
457
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 sctp_bh_lock_sock(sk);
459
460 /* If too many ICMPs get dropped on busy
461 * servers this needs to be solved differently.
462 */
463 if (sock_owned_by_user(sk))
464 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 *app = asoc;
467 *tpp = transport;
468 return sk;
469
470out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 if (asoc)
472 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 return NULL;
474}
475
476/* Common cleanup code for icmp/icmpv6 error handler. */
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700477void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478{
479 sctp_bh_unlock_sock(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 if (asoc)
481 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482}
483
484/*
485 * This routine is called by the ICMP module when it gets some
486 * sort of error condition. If err < 0 then the socket should
487 * be closed and the error returned to the user. If err > 0
488 * it's just the icmp type << 8 | icmp code. After adjustment
489 * header points to the first 8 bytes of the sctp header. We need
490 * to find the appropriate port.
491 *
492 * The locking strategy used here is very "optimistic". When
493 * someone else accesses the socket the ICMP is just dropped
494 * and for some paths there is no check at all.
495 * A more general error queue to queue errors for later handling
496 * is probably better.
497 *
498 */
499void sctp_v4_err(struct sk_buff *skb, __u32 info)
500{
501 struct iphdr *iph = (struct iphdr *)skb->data;
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300502 const int ihlen = iph->ihl * 4;
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300503 const int type = icmp_hdr(skb)->type;
504 const int code = icmp_hdr(skb)->code;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 struct sock *sk;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700506 struct sctp_association *asoc = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 struct sctp_transport *transport;
508 struct inet_sock *inet;
Arnaldo Carvalho de Melo2e07fa92007-04-10 21:22:35 -0700509 sk_buff_data_t saveip, savesctp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 int err;
511
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300512 if (skb->len < ihlen + 8) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
514 return;
515 }
516
517 /* Fix up skb to look at the embedded net header. */
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700518 saveip = skb->network_header;
519 savesctp = skb->transport_header;
Arnaldo Carvalho de Melo31c77112007-03-10 19:04:55 -0300520 skb_reset_network_header(skb);
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300521 skb_set_transport_header(skb, ihlen);
522 sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
Arnaldo Carvalho de Melo2e07fa92007-04-10 21:22:35 -0700523 /* Put back, the original values. */
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700524 skb->network_header = saveip;
525 skb->transport_header = savesctp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 if (!sk) {
527 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
528 return;
529 }
530 /* Warning: The sock lock is held. Remember to call
531 * sctp_err_finish!
532 */
533
534 switch (type) {
535 case ICMP_PARAMETERPROB:
536 err = EPROTO;
537 break;
538 case ICMP_DEST_UNREACH:
539 if (code > NR_ICMP_UNREACH)
540 goto out_unlock;
541
542 /* PMTU discovery (RFC1191) */
543 if (ICMP_FRAG_NEEDED == code) {
544 sctp_icmp_frag_needed(sk, asoc, transport, info);
545 goto out_unlock;
546 }
547 else {
548 if (ICMP_PROT_UNREACH == code) {
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700549 sctp_icmp_proto_unreachable(sk, asoc,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 transport);
551 goto out_unlock;
552 }
553 }
554 err = icmp_err_convert[code].errno;
555 break;
556 case ICMP_TIME_EXCEEDED:
557 /* Ignore any time exceeded errors due to fragment reassembly
558 * timeouts.
559 */
560 if (ICMP_EXC_FRAGTIME == code)
561 goto out_unlock;
562
563 err = EHOSTUNREACH;
564 break;
565 default:
566 goto out_unlock;
567 }
568
569 inet = inet_sk(sk);
570 if (!sock_owned_by_user(sk) && inet->recverr) {
571 sk->sk_err = err;
572 sk->sk_error_report(sk);
573 } else { /* Only an error on timeout */
574 sk->sk_err_soft = err;
575 }
576
577out_unlock:
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700578 sctp_err_finish(sk, asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579}
580
581/*
582 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
583 *
584 * This function scans all the chunks in the OOTB packet to determine if
585 * the packet should be discarded right away. If a response might be needed
586 * for this packet, or, if further processing is possible, the packet will
587 * be queued to a proper inqueue for the next phase of handling.
588 *
589 * Output:
590 * Return 0 - If further processing is needed.
591 * Return 1 - If the packet can be discarded right away.
592 */
593int sctp_rcv_ootb(struct sk_buff *skb)
594{
595 sctp_chunkhdr_t *ch;
596 __u8 *ch_end;
597 sctp_errhdr_t *err;
598
599 ch = (sctp_chunkhdr_t *) skb->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600
601 /* Scan through all the chunks in the packet. */
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800602 do {
603 /* Break out if chunk length is less then minimal. */
604 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
605 break;
606
607 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700608 if (ch_end > skb_tail_pointer(skb))
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800609 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610
611 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
612 * receiver MUST silently discard the OOTB packet and take no
613 * further action.
614 */
615 if (SCTP_CID_ABORT == ch->type)
616 goto discard;
617
618 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
619 * chunk, the receiver should silently discard the packet
620 * and take no further action.
621 */
622 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
623 goto discard;
624
625 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
626 * or a COOKIE ACK the SCTP Packet should be silently
627 * discarded.
628 */
629 if (SCTP_CID_COOKIE_ACK == ch->type)
630 goto discard;
631
632 if (SCTP_CID_ERROR == ch->type) {
633 sctp_walk_errors(err, ch) {
634 if (SCTP_ERROR_STALE_COOKIE == err->cause)
635 goto discard;
636 }
637 }
638
639 ch = (sctp_chunkhdr_t *) ch_end;
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700640 } while (ch_end < skb_tail_pointer(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641
642 return 0;
643
644discard:
645 return 1;
646}
647
648/* Insert endpoint into the hash table. */
649static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
650{
651 struct sctp_ep_common **epp;
652 struct sctp_ep_common *epb;
653 struct sctp_hashbucket *head;
654
655 epb = &ep->base;
656
657 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
658 head = &sctp_ep_hashtable[epb->hashent];
659
660 sctp_write_lock(&head->lock);
661 epp = &head->chain;
662 epb->next = *epp;
663 if (epb->next)
664 (*epp)->pprev = &epb->next;
665 *epp = epb;
666 epb->pprev = epp;
667 sctp_write_unlock(&head->lock);
668}
669
670/* Add an endpoint to the hash. Local BH-safe. */
671void sctp_hash_endpoint(struct sctp_endpoint *ep)
672{
673 sctp_local_bh_disable();
674 __sctp_hash_endpoint(ep);
675 sctp_local_bh_enable();
676}
677
678/* Remove endpoint from the hash table. */
679static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
680{
681 struct sctp_hashbucket *head;
682 struct sctp_ep_common *epb;
683
684 epb = &ep->base;
685
686 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
687
688 head = &sctp_ep_hashtable[epb->hashent];
689
690 sctp_write_lock(&head->lock);
691
692 if (epb->pprev) {
693 if (epb->next)
694 epb->next->pprev = epb->pprev;
695 *epb->pprev = epb->next;
696 epb->pprev = NULL;
697 }
698
699 sctp_write_unlock(&head->lock);
700}
701
702/* Remove endpoint from the hash. Local BH-safe. */
703void sctp_unhash_endpoint(struct sctp_endpoint *ep)
704{
705 sctp_local_bh_disable();
706 __sctp_unhash_endpoint(ep);
707 sctp_local_bh_enable();
708}
709
710/* Look up an endpoint. */
711static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr)
712{
713 struct sctp_hashbucket *head;
714 struct sctp_ep_common *epb;
715 struct sctp_endpoint *ep;
716 int hash;
717
Al Viro1c7d1fc2006-11-20 17:08:09 -0800718 hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700719 head = &sctp_ep_hashtable[hash];
720 read_lock(&head->lock);
721 for (epb = head->chain; epb; epb = epb->next) {
722 ep = sctp_ep(epb);
723 if (sctp_endpoint_is_match(ep, laddr))
724 goto hit;
725 }
726
727 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
728 epb = &ep->base;
729
730hit:
731 sctp_endpoint_hold(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 read_unlock(&head->lock);
733 return ep;
734}
735
736/* Insert association into the hash table. */
737static void __sctp_hash_established(struct sctp_association *asoc)
738{
739 struct sctp_ep_common **epp;
740 struct sctp_ep_common *epb;
741 struct sctp_hashbucket *head;
742
743 epb = &asoc->base;
744
745 /* Calculate which chain this entry will belong to. */
746 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port);
747
748 head = &sctp_assoc_hashtable[epb->hashent];
749
750 sctp_write_lock(&head->lock);
751 epp = &head->chain;
752 epb->next = *epp;
753 if (epb->next)
754 (*epp)->pprev = &epb->next;
755 *epp = epb;
756 epb->pprev = epp;
757 sctp_write_unlock(&head->lock);
758}
759
760/* Add an association to the hash. Local BH-safe. */
761void sctp_hash_established(struct sctp_association *asoc)
762{
Vlad Yasevichde76e692006-10-30 18:55:11 -0800763 if (asoc->temp)
764 return;
765
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 sctp_local_bh_disable();
767 __sctp_hash_established(asoc);
768 sctp_local_bh_enable();
769}
770
771/* Remove association from the hash table. */
772static void __sctp_unhash_established(struct sctp_association *asoc)
773{
774 struct sctp_hashbucket *head;
775 struct sctp_ep_common *epb;
776
777 epb = &asoc->base;
778
779 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port,
780 asoc->peer.port);
781
782 head = &sctp_assoc_hashtable[epb->hashent];
783
784 sctp_write_lock(&head->lock);
785
786 if (epb->pprev) {
787 if (epb->next)
788 epb->next->pprev = epb->pprev;
789 *epb->pprev = epb->next;
790 epb->pprev = NULL;
791 }
792
793 sctp_write_unlock(&head->lock);
794}
795
796/* Remove association from the hash table. Local BH-safe. */
797void sctp_unhash_established(struct sctp_association *asoc)
798{
Vlad Yasevichde76e692006-10-30 18:55:11 -0800799 if (asoc->temp)
800 return;
801
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 sctp_local_bh_disable();
803 __sctp_unhash_established(asoc);
804 sctp_local_bh_enable();
805}
806
807/* Look up an association. */
808static struct sctp_association *__sctp_lookup_association(
809 const union sctp_addr *local,
810 const union sctp_addr *peer,
811 struct sctp_transport **pt)
812{
813 struct sctp_hashbucket *head;
814 struct sctp_ep_common *epb;
815 struct sctp_association *asoc;
816 struct sctp_transport *transport;
817 int hash;
818
819 /* Optimize here for direct hit, only listening connections can
820 * have wildcards anyways.
821 */
Al Viroe2fcced2006-11-20 17:08:41 -0800822 hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 head = &sctp_assoc_hashtable[hash];
824 read_lock(&head->lock);
825 for (epb = head->chain; epb; epb = epb->next) {
826 asoc = sctp_assoc(epb);
827 transport = sctp_assoc_is_match(asoc, local, peer);
828 if (transport)
829 goto hit;
830 }
831
832 read_unlock(&head->lock);
833
834 return NULL;
835
836hit:
837 *pt = transport;
838 sctp_association_hold(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 read_unlock(&head->lock);
840 return asoc;
841}
842
843/* Look up an association. BH-safe. */
844SCTP_STATIC
845struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr,
846 const union sctp_addr *paddr,
847 struct sctp_transport **transportp)
848{
849 struct sctp_association *asoc;
850
851 sctp_local_bh_disable();
852 asoc = __sctp_lookup_association(laddr, paddr, transportp);
853 sctp_local_bh_enable();
854
855 return asoc;
856}
857
858/* Is there an association matching the given local and peer addresses? */
859int sctp_has_association(const union sctp_addr *laddr,
860 const union sctp_addr *paddr)
861{
862 struct sctp_association *asoc;
863 struct sctp_transport *transport;
864
Al Viro6c7be552006-11-20 17:11:50 -0800865 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 sctp_association_put(asoc);
867 return 1;
868 }
869
870 return 0;
871}
872
873/*
874 * SCTP Implementors Guide, 2.18 Handling of address
875 * parameters within the INIT or INIT-ACK.
876 *
877 * D) When searching for a matching TCB upon reception of an INIT
878 * or INIT-ACK chunk the receiver SHOULD use not only the
879 * source address of the packet (containing the INIT or
880 * INIT-ACK) but the receiver SHOULD also use all valid
881 * address parameters contained within the chunk.
882 *
883 * 2.18.3 Solution description
884 *
885 * This new text clearly specifies to an implementor the need
886 * to look within the INIT or INIT-ACK. Any implementation that
887 * does not do this, may not be able to establish associations
888 * in certain circumstances.
889 *
890 */
891static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
892 const union sctp_addr *laddr, struct sctp_transport **transportp)
893{
894 struct sctp_association *asoc;
895 union sctp_addr addr;
896 union sctp_addr *paddr = &addr;
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -0300897 struct sctphdr *sh = sctp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 sctp_chunkhdr_t *ch;
899 union sctp_params params;
900 sctp_init_chunk_t *init;
901 struct sctp_transport *transport;
902 struct sctp_af *af;
903
904 ch = (sctp_chunkhdr_t *) skb->data;
905
906 /* If this is INIT/INIT-ACK look inside the chunk too. */
907 switch (ch->type) {
908 case SCTP_CID_INIT:
909 case SCTP_CID_INIT_ACK:
910 break;
911 default:
912 return NULL;
913 }
914
915 /* The code below will attempt to walk the chunk and extract
916 * parameter information. Before we do that, we need to verify
917 * that the chunk length doesn't cause overflow. Otherwise, we'll
918 * walk off the end.
919 */
920 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
921 return NULL;
922
923 /*
924 * This code will NOT touch anything inside the chunk--it is
925 * strictly READ-ONLY.
926 *
927 * RFC 2960 3 SCTP packet Format
928 *
929 * Multiple chunks can be bundled into one SCTP packet up to
930 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
931 * COMPLETE chunks. These chunks MUST NOT be bundled with any
932 * other chunk in a packet. See Section 6.10 for more details
933 * on chunk bundling.
934 */
935
936 /* Find the start of the TLVs and the end of the chunk. This is
937 * the region we search for address parameters.
938 */
939 init = (sctp_init_chunk_t *)skb->data;
940
941 /* Walk the parameters looking for embedded addresses. */
942 sctp_walk_params(params, init, init_hdr.params) {
943
944 /* Note: Ignoring hostname addresses. */
945 af = sctp_get_af_specific(param_type2af(params.p->type));
946 if (!af)
947 continue;
948
Al Virodd86d132006-11-20 17:11:13 -0800949 af->from_addr_param(paddr, params.addr, sh->source, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950
Al Virodd86d132006-11-20 17:11:13 -0800951 asoc = __sctp_lookup_association(laddr, paddr, &transport);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952 if (asoc)
953 return asoc;
954 }
955
956 return NULL;
957}
958
959/* Lookup an association for an inbound skb. */
960static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
961 const union sctp_addr *paddr,
962 const union sctp_addr *laddr,
963 struct sctp_transport **transportp)
964{
965 struct sctp_association *asoc;
966
967 asoc = __sctp_lookup_association(laddr, paddr, transportp);
968
969 /* Further lookup for INIT/INIT-ACK packets.
970 * SCTP Implementors Guide, 2.18 Handling of address
971 * parameters within the INIT or INIT-ACK.
972 */
973 if (!asoc)
974 asoc = __sctp_rcv_init_lookup(skb, laddr, transportp);
975
976 return asoc;
977}