blob: 42b66e74bbb504cf38b7ea088895ab49a7446280 [file] [log] [blame]
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{
82 struct sctphdr *sh;
83 __u32 cmp, val;
84 struct sk_buff *list = skb_shinfo(skb)->frag_list;
85
86 sh = (struct sctphdr *) skb->h.raw;
87 cmp = ntohl(sh->checksum);
88
89 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
90
91 for (; list; list = list->next)
92 val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
93 val);
94
95 val = sctp_end_cksum(val);
96
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
138 sh = (struct sctphdr *) skb->h.raw;
139
140 /* Pull up the IP and SCTP headers. */
141 __skb_pull(skb, skb->h.raw - skb->data);
142 if (skb->len < sizeof(struct sctphdr))
143 goto discard_it;
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700144 if ((skb->ip_summed != CHECKSUM_UNNECESSARY) &&
145 (sctp_rcv_checksum(skb) < 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 goto discard_it;
147
148 skb_pull(skb, sizeof(struct sctphdr));
149
150 /* Make sure we at least have chunk headers worth of data left. */
151 if (skb->len < sizeof(struct sctp_chunkhdr))
152 goto discard_it;
153
154 family = ipver2af(skb->nh.iph->version);
155 af = sctp_get_af_specific(family);
156 if (unlikely(!af))
157 goto discard_it;
158
159 /* Initialize local addresses for lookups. */
160 af->from_skb(&src, skb, 1);
161 af->from_skb(&dest, skb, 0);
162
163 /* If the packet is to or from a non-unicast address,
164 * silently discard the packet.
165 *
166 * This is not clearly defined in the RFC except in section
167 * 8.4 - OOTB handling. However, based on the book "Stream Control
168 * Transmission Protocol" 2.1, "It is important to note that the
169 * IP address of an SCTP transport address must be a routable
170 * unicast address. In other words, IP multicast addresses and
171 * IP broadcast addresses cannot be used in an SCTP transport
172 * address."
173 */
Vlad Yasevich5636bef2006-06-17 22:55:35 -0700174 if (!af->addr_valid(&src, NULL, skb) ||
175 !af->addr_valid(&dest, NULL, skb))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 goto discard_it;
177
178 asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport);
179
Neil Horman0fd9a652005-06-13 15:11:24 -0700180 if (!asoc)
181 ep = __sctp_rcv_lookup_endpoint(&dest);
182
183 /* Retrieve the common input handling substructure. */
184 rcvr = asoc ? &asoc->base : &ep->base;
185 sk = rcvr->sk;
186
187 /*
188 * If a frame arrives on an interface and the receiving socket is
189 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
190 */
191 if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb)))
192 {
Neil Horman0fd9a652005-06-13 15:11:24 -0700193 if (asoc) {
194 sctp_association_put(asoc);
195 asoc = NULL;
196 } else {
197 sctp_endpoint_put(ep);
198 ep = NULL;
199 }
200 sk = sctp_get_ctl_sock();
201 ep = sctp_sk(sk)->ep;
202 sctp_endpoint_hold(ep);
Neil Horman0fd9a652005-06-13 15:11:24 -0700203 rcvr = &ep->base;
204 }
205
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 /*
207 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
208 * An SCTP packet is called an "out of the blue" (OOTB)
209 * packet if it is correctly formed, i.e., passed the
210 * receiver's checksum check, but the receiver is not
211 * able to identify the association to which this
212 * packet belongs.
213 */
214 if (!asoc) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 if (sctp_rcv_ootb(skb)) {
216 SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES);
217 goto discard_release;
218 }
219 }
220
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221 /* SCTP seems to always need a timestamp right now (FIXME) */
Patrick McHardya61bbcf2005-08-14 17:24:31 -0700222 if (skb->tstamp.off_sec == 0) {
223 __net_timestamp(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 sock_enable_timestamp(sk);
225 }
226
227 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
228 goto discard_release;
Patrick McHardyb59c2702006-01-06 23:06:10 -0800229 nf_reset(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
Herbert Xu2babf9d2006-03-25 01:25:29 -0800231 if (sk_filter(sk, skb, 1))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 goto discard_release;
233
234 /* Create an SCTP packet structure. */
235 chunk = sctp_chunkify(skb, asoc, sk);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800236 if (!chunk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 goto discard_release;
David S. Miller79af02c2005-07-08 21:47:49 -0700238 SCTP_INPUT_CB(skb)->chunk = chunk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 /* Remember what endpoint is to handle this packet. */
241 chunk->rcvr = rcvr;
242
243 /* Remember the SCTP header. */
244 chunk->sctp_hdr = sh;
245
246 /* Set the source and destination addresses of the incoming chunk. */
247 sctp_init_addrs(chunk, &src, &dest);
248
249 /* Remember where we came from. */
250 chunk->transport = transport;
251
252 /* Acquire access to the sock lock. Note: We are safe from other
253 * bottom halves on this lock, but a user may be in the lock too,
254 * so check if it is busy.
255 */
256 sctp_bh_lock_sock(sk);
257
258 if (sock_owned_by_user(sk))
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700259 sctp_add_backlog(sk, skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 else
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700261 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 sctp_bh_unlock_sock(sk);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700264
265 /* Release the asoc/ep ref we took in the lookup calls. */
266 if (asoc)
267 sctp_association_put(asoc);
268 else
269 sctp_endpoint_put(ep);
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800270
Herbert Xu2babf9d2006-03-25 01:25:29 -0800271 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
273discard_it:
274 kfree_skb(skb);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800275 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276
277discard_release:
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700278 /* Release the asoc/ep ref we took in the lookup calls. */
Neil Horman0fd9a652005-06-13 15:11:24 -0700279 if (asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 sctp_association_put(asoc);
Neil Horman0fd9a652005-06-13 15:11:24 -0700281 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700282 sctp_endpoint_put(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283
284 goto discard_it;
285}
286
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700287/* Process the backlog queue of the socket. Every skb on
288 * the backlog holds a ref on an association or endpoint.
289 * We hold this ref throughout the state machine to make
290 * sure that the structure we need is still around.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 */
292int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
293{
David S. Miller79af02c2005-07-08 21:47:49 -0700294 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700295 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800296 struct sctp_ep_common *rcvr = NULL;
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700297 int backloged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800299 rcvr = chunk->rcvr;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800300
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700301 /* If the rcvr is dead then the association or endpoint
302 * has been deleted and we can safely drop the chunk
303 * and refs that we are holding.
304 */
305 if (rcvr->dead) {
306 sctp_chunk_free(chunk);
307 goto done;
308 }
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800309
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700310 if (unlikely(rcvr->sk != sk)) {
311 /* In this case, the association moved from one socket to
312 * another. We are currently sitting on the backlog of the
313 * old socket, so we need to move.
314 * However, since we are here in the process context we
315 * need to take make sure that the user doesn't own
316 * the new socket when we process the packet.
317 * If the new socket is user-owned, queue the chunk to the
318 * backlog of the new socket without dropping any refs.
319 * Otherwise, we can safely push the chunk on the inqueue.
320 */
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800321
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700322 sk = rcvr->sk;
323 sctp_bh_lock_sock(sk);
324
325 if (sock_owned_by_user(sk)) {
326 sk_add_backlog(sk, skb);
327 backloged = 1;
328 } else
329 sctp_inq_push(inqueue, chunk);
330
331 sctp_bh_unlock_sock(sk);
332
333 /* If the chunk was backloged again, don't drop refs */
334 if (backloged)
335 return 0;
336 } else {
337 sctp_inq_push(inqueue, chunk);
338 }
339
340done:
341 /* Release the refs we took in sctp_add_backlog */
342 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
343 sctp_association_put(sctp_assoc(rcvr));
344 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
345 sctp_endpoint_put(sctp_ep(rcvr));
346 else
347 BUG();
348
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 return 0;
350}
351
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700352static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800353{
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700354 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
355 struct sctp_ep_common *rcvr = chunk->rcvr;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800356
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700357 /* Hold the assoc/ep while hanging on the backlog queue.
358 * This way, we know structures we need will not disappear from us
359 */
360 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
361 sctp_association_hold(sctp_assoc(rcvr));
362 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
363 sctp_endpoint_hold(sctp_ep(rcvr));
364 else
365 BUG();
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800366
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700367 sk_add_backlog(sk, skb);
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800368}
369
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370/* Handle icmp frag needed error. */
371void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
372 struct sctp_transport *t, __u32 pmtu)
373{
Frank Filz52ccb8e2005-12-22 11:36:46 -0800374 if (sock_owned_by_user(sk) || !t || (t->pathmtu == pmtu))
375 return;
376
377 if (t->param_flags & SPP_PMTUD_ENABLE) {
378 if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
379 printk(KERN_WARNING "%s: Reported pmtu %d too low, "
380 "using default minimum of %d\n",
381 __FUNCTION__, pmtu,
382 SCTP_DEFAULT_MINSEGMENT);
383 /* Use default minimum segment size and disable
384 * pmtu discovery on this transport.
385 */
386 t->pathmtu = SCTP_DEFAULT_MINSEGMENT;
387 t->param_flags = (t->param_flags & ~SPP_HB) |
388 SPP_PMTUD_DISABLE;
389 } else {
390 t->pathmtu = pmtu;
391 }
392
393 /* Update association pmtu. */
394 sctp_assoc_sync_pmtu(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 }
396
Frank Filz52ccb8e2005-12-22 11:36:46 -0800397 /* Retransmit with the new pmtu setting.
398 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
399 * Needed will never be sent, but if a message was sent before
400 * PMTU discovery was disabled that was larger than the PMTU, it
401 * would not be fragmented, so it must be re-transmitted fragmented.
402 */
403 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404}
405
406/*
407 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
408 *
409 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
410 * or a "Protocol Unreachable" treat this message as an abort
411 * with the T bit set.
412 *
413 * This function sends an event to the state machine, which will abort the
414 * association.
415 *
416 */
417void sctp_icmp_proto_unreachable(struct sock *sk,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 struct sctp_association *asoc,
419 struct sctp_transport *t)
420{
421 SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__);
422
423 sctp_do_sm(SCTP_EVENT_T_OTHER,
424 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
Frank Filz3f7a87d2005-06-20 13:14:57 -0700425 asoc->state, asoc->ep, asoc, t,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 GFP_ATOMIC);
427
428}
429
430/* Common lookup code for icmp/icmpv6 error handler. */
431struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
432 struct sctphdr *sctphdr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 struct sctp_association **app,
434 struct sctp_transport **tpp)
435{
436 union sctp_addr saddr;
437 union sctp_addr daddr;
438 struct sctp_af *af;
439 struct sock *sk = NULL;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700440 struct sctp_association *asoc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 struct sctp_transport *transport = NULL;
442
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700443 *app = NULL; *tpp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444
445 af = sctp_get_af_specific(family);
446 if (unlikely(!af)) {
447 return NULL;
448 }
449
450 /* Initialize local addresses for lookups. */
451 af->from_skb(&saddr, skb, 1);
452 af->from_skb(&daddr, skb, 0);
453
454 /* Look for an association that matches the incoming ICMP error
455 * packet.
456 */
457 asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700458 if (!asoc)
459 return NULL;
460
461 sk = asoc->base.sk;
462
463 if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) {
464 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
465 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 }
467
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 sctp_bh_lock_sock(sk);
469
470 /* If too many ICMPs get dropped on busy
471 * servers this needs to be solved differently.
472 */
473 if (sock_owned_by_user(sk))
474 NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
475
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 *app = asoc;
477 *tpp = transport;
478 return sk;
479
480out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 if (asoc)
482 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 return NULL;
484}
485
486/* Common cleanup code for icmp/icmpv6 error handler. */
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700487void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488{
489 sctp_bh_unlock_sock(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 if (asoc)
491 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492}
493
494/*
495 * This routine is called by the ICMP module when it gets some
496 * sort of error condition. If err < 0 then the socket should
497 * be closed and the error returned to the user. If err > 0
498 * it's just the icmp type << 8 | icmp code. After adjustment
499 * header points to the first 8 bytes of the sctp header. We need
500 * to find the appropriate port.
501 *
502 * The locking strategy used here is very "optimistic". When
503 * someone else accesses the socket the ICMP is just dropped
504 * and for some paths there is no check at all.
505 * A more general error queue to queue errors for later handling
506 * is probably better.
507 *
508 */
509void sctp_v4_err(struct sk_buff *skb, __u32 info)
510{
511 struct iphdr *iph = (struct iphdr *)skb->data;
512 struct sctphdr *sh = (struct sctphdr *)(skb->data + (iph->ihl <<2));
513 int type = skb->h.icmph->type;
514 int code = skb->h.icmph->code;
515 struct sock *sk;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700516 struct sctp_association *asoc = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 struct sctp_transport *transport;
518 struct inet_sock *inet;
519 char *saveip, *savesctp;
520 int err;
521
522 if (skb->len < ((iph->ihl << 2) + 8)) {
523 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
524 return;
525 }
526
527 /* Fix up skb to look at the embedded net header. */
528 saveip = skb->nh.raw;
529 savesctp = skb->h.raw;
530 skb->nh.iph = iph;
531 skb->h.raw = (char *)sh;
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700532 sk = sctp_err_lookup(AF_INET, skb, sh, &asoc, &transport);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 /* Put back, the original pointers. */
534 skb->nh.raw = saveip;
535 skb->h.raw = savesctp;
536 if (!sk) {
537 ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
538 return;
539 }
540 /* Warning: The sock lock is held. Remember to call
541 * sctp_err_finish!
542 */
543
544 switch (type) {
545 case ICMP_PARAMETERPROB:
546 err = EPROTO;
547 break;
548 case ICMP_DEST_UNREACH:
549 if (code > NR_ICMP_UNREACH)
550 goto out_unlock;
551
552 /* PMTU discovery (RFC1191) */
553 if (ICMP_FRAG_NEEDED == code) {
554 sctp_icmp_frag_needed(sk, asoc, transport, info);
555 goto out_unlock;
556 }
557 else {
558 if (ICMP_PROT_UNREACH == code) {
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700559 sctp_icmp_proto_unreachable(sk, asoc,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 transport);
561 goto out_unlock;
562 }
563 }
564 err = icmp_err_convert[code].errno;
565 break;
566 case ICMP_TIME_EXCEEDED:
567 /* Ignore any time exceeded errors due to fragment reassembly
568 * timeouts.
569 */
570 if (ICMP_EXC_FRAGTIME == code)
571 goto out_unlock;
572
573 err = EHOSTUNREACH;
574 break;
575 default:
576 goto out_unlock;
577 }
578
579 inet = inet_sk(sk);
580 if (!sock_owned_by_user(sk) && inet->recverr) {
581 sk->sk_err = err;
582 sk->sk_error_report(sk);
583 } else { /* Only an error on timeout */
584 sk->sk_err_soft = err;
585 }
586
587out_unlock:
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700588 sctp_err_finish(sk, asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589}
590
591/*
592 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
593 *
594 * This function scans all the chunks in the OOTB packet to determine if
595 * the packet should be discarded right away. If a response might be needed
596 * for this packet, or, if further processing is possible, the packet will
597 * be queued to a proper inqueue for the next phase of handling.
598 *
599 * Output:
600 * Return 0 - If further processing is needed.
601 * Return 1 - If the packet can be discarded right away.
602 */
603int sctp_rcv_ootb(struct sk_buff *skb)
604{
605 sctp_chunkhdr_t *ch;
606 __u8 *ch_end;
607 sctp_errhdr_t *err;
608
609 ch = (sctp_chunkhdr_t *) skb->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610
611 /* Scan through all the chunks in the packet. */
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800612 do {
613 /* Break out if chunk length is less then minimal. */
614 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
615 break;
616
617 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
618 if (ch_end > skb->tail)
619 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620
621 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
622 * receiver MUST silently discard the OOTB packet and take no
623 * further action.
624 */
625 if (SCTP_CID_ABORT == ch->type)
626 goto discard;
627
628 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
629 * chunk, the receiver should silently discard the packet
630 * and take no further action.
631 */
632 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
633 goto discard;
634
635 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
636 * or a COOKIE ACK the SCTP Packet should be silently
637 * discarded.
638 */
639 if (SCTP_CID_COOKIE_ACK == ch->type)
640 goto discard;
641
642 if (SCTP_CID_ERROR == ch->type) {
643 sctp_walk_errors(err, ch) {
644 if (SCTP_ERROR_STALE_COOKIE == err->cause)
645 goto discard;
646 }
647 }
648
649 ch = (sctp_chunkhdr_t *) ch_end;
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800650 } while (ch_end < skb->tail);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651
652 return 0;
653
654discard:
655 return 1;
656}
657
658/* Insert endpoint into the hash table. */
659static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
660{
661 struct sctp_ep_common **epp;
662 struct sctp_ep_common *epb;
663 struct sctp_hashbucket *head;
664
665 epb = &ep->base;
666
667 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
668 head = &sctp_ep_hashtable[epb->hashent];
669
670 sctp_write_lock(&head->lock);
671 epp = &head->chain;
672 epb->next = *epp;
673 if (epb->next)
674 (*epp)->pprev = &epb->next;
675 *epp = epb;
676 epb->pprev = epp;
677 sctp_write_unlock(&head->lock);
678}
679
680/* Add an endpoint to the hash. Local BH-safe. */
681void sctp_hash_endpoint(struct sctp_endpoint *ep)
682{
683 sctp_local_bh_disable();
684 __sctp_hash_endpoint(ep);
685 sctp_local_bh_enable();
686}
687
688/* Remove endpoint from the hash table. */
689static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
690{
691 struct sctp_hashbucket *head;
692 struct sctp_ep_common *epb;
693
694 epb = &ep->base;
695
696 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
697
698 head = &sctp_ep_hashtable[epb->hashent];
699
700 sctp_write_lock(&head->lock);
701
702 if (epb->pprev) {
703 if (epb->next)
704 epb->next->pprev = epb->pprev;
705 *epb->pprev = epb->next;
706 epb->pprev = NULL;
707 }
708
709 sctp_write_unlock(&head->lock);
710}
711
712/* Remove endpoint from the hash. Local BH-safe. */
713void sctp_unhash_endpoint(struct sctp_endpoint *ep)
714{
715 sctp_local_bh_disable();
716 __sctp_unhash_endpoint(ep);
717 sctp_local_bh_enable();
718}
719
720/* Look up an endpoint. */
721static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr)
722{
723 struct sctp_hashbucket *head;
724 struct sctp_ep_common *epb;
725 struct sctp_endpoint *ep;
726 int hash;
727
728 hash = sctp_ep_hashfn(laddr->v4.sin_port);
729 head = &sctp_ep_hashtable[hash];
730 read_lock(&head->lock);
731 for (epb = head->chain; epb; epb = epb->next) {
732 ep = sctp_ep(epb);
733 if (sctp_endpoint_is_match(ep, laddr))
734 goto hit;
735 }
736
737 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
738 epb = &ep->base;
739
740hit:
741 sctp_endpoint_hold(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 read_unlock(&head->lock);
743 return ep;
744}
745
746/* Insert association into the hash table. */
747static void __sctp_hash_established(struct sctp_association *asoc)
748{
749 struct sctp_ep_common **epp;
750 struct sctp_ep_common *epb;
751 struct sctp_hashbucket *head;
752
753 epb = &asoc->base;
754
755 /* Calculate which chain this entry will belong to. */
756 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port);
757
758 head = &sctp_assoc_hashtable[epb->hashent];
759
760 sctp_write_lock(&head->lock);
761 epp = &head->chain;
762 epb->next = *epp;
763 if (epb->next)
764 (*epp)->pprev = &epb->next;
765 *epp = epb;
766 epb->pprev = epp;
767 sctp_write_unlock(&head->lock);
768}
769
770/* Add an association to the hash. Local BH-safe. */
771void sctp_hash_established(struct sctp_association *asoc)
772{
773 sctp_local_bh_disable();
774 __sctp_hash_established(asoc);
775 sctp_local_bh_enable();
776}
777
778/* Remove association from the hash table. */
779static void __sctp_unhash_established(struct sctp_association *asoc)
780{
781 struct sctp_hashbucket *head;
782 struct sctp_ep_common *epb;
783
784 epb = &asoc->base;
785
786 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port,
787 asoc->peer.port);
788
789 head = &sctp_assoc_hashtable[epb->hashent];
790
791 sctp_write_lock(&head->lock);
792
793 if (epb->pprev) {
794 if (epb->next)
795 epb->next->pprev = epb->pprev;
796 *epb->pprev = epb->next;
797 epb->pprev = NULL;
798 }
799
800 sctp_write_unlock(&head->lock);
801}
802
803/* Remove association from the hash table. Local BH-safe. */
804void sctp_unhash_established(struct sctp_association *asoc)
805{
806 sctp_local_bh_disable();
807 __sctp_unhash_established(asoc);
808 sctp_local_bh_enable();
809}
810
811/* Look up an association. */
812static struct sctp_association *__sctp_lookup_association(
813 const union sctp_addr *local,
814 const union sctp_addr *peer,
815 struct sctp_transport **pt)
816{
817 struct sctp_hashbucket *head;
818 struct sctp_ep_common *epb;
819 struct sctp_association *asoc;
820 struct sctp_transport *transport;
821 int hash;
822
823 /* Optimize here for direct hit, only listening connections can
824 * have wildcards anyways.
825 */
826 hash = sctp_assoc_hashfn(local->v4.sin_port, peer->v4.sin_port);
827 head = &sctp_assoc_hashtable[hash];
828 read_lock(&head->lock);
829 for (epb = head->chain; epb; epb = epb->next) {
830 asoc = sctp_assoc(epb);
831 transport = sctp_assoc_is_match(asoc, local, peer);
832 if (transport)
833 goto hit;
834 }
835
836 read_unlock(&head->lock);
837
838 return NULL;
839
840hit:
841 *pt = transport;
842 sctp_association_hold(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 read_unlock(&head->lock);
844 return asoc;
845}
846
847/* Look up an association. BH-safe. */
848SCTP_STATIC
849struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr,
850 const union sctp_addr *paddr,
851 struct sctp_transport **transportp)
852{
853 struct sctp_association *asoc;
854
855 sctp_local_bh_disable();
856 asoc = __sctp_lookup_association(laddr, paddr, transportp);
857 sctp_local_bh_enable();
858
859 return asoc;
860}
861
862/* Is there an association matching the given local and peer addresses? */
863int sctp_has_association(const union sctp_addr *laddr,
864 const union sctp_addr *paddr)
865{
866 struct sctp_association *asoc;
867 struct sctp_transport *transport;
868
869 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 sctp_association_put(asoc);
871 return 1;
872 }
873
874 return 0;
875}
876
877/*
878 * SCTP Implementors Guide, 2.18 Handling of address
879 * parameters within the INIT or INIT-ACK.
880 *
881 * D) When searching for a matching TCB upon reception of an INIT
882 * or INIT-ACK chunk the receiver SHOULD use not only the
883 * source address of the packet (containing the INIT or
884 * INIT-ACK) but the receiver SHOULD also use all valid
885 * address parameters contained within the chunk.
886 *
887 * 2.18.3 Solution description
888 *
889 * This new text clearly specifies to an implementor the need
890 * to look within the INIT or INIT-ACK. Any implementation that
891 * does not do this, may not be able to establish associations
892 * in certain circumstances.
893 *
894 */
895static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
896 const union sctp_addr *laddr, struct sctp_transport **transportp)
897{
898 struct sctp_association *asoc;
899 union sctp_addr addr;
900 union sctp_addr *paddr = &addr;
901 struct sctphdr *sh = (struct sctphdr *) skb->h.raw;
902 sctp_chunkhdr_t *ch;
903 union sctp_params params;
904 sctp_init_chunk_t *init;
905 struct sctp_transport *transport;
906 struct sctp_af *af;
907
908 ch = (sctp_chunkhdr_t *) skb->data;
909
910 /* If this is INIT/INIT-ACK look inside the chunk too. */
911 switch (ch->type) {
912 case SCTP_CID_INIT:
913 case SCTP_CID_INIT_ACK:
914 break;
915 default:
916 return NULL;
917 }
918
919 /* The code below will attempt to walk the chunk and extract
920 * parameter information. Before we do that, we need to verify
921 * that the chunk length doesn't cause overflow. Otherwise, we'll
922 * walk off the end.
923 */
924 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
925 return NULL;
926
927 /*
928 * This code will NOT touch anything inside the chunk--it is
929 * strictly READ-ONLY.
930 *
931 * RFC 2960 3 SCTP packet Format
932 *
933 * Multiple chunks can be bundled into one SCTP packet up to
934 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
935 * COMPLETE chunks. These chunks MUST NOT be bundled with any
936 * other chunk in a packet. See Section 6.10 for more details
937 * on chunk bundling.
938 */
939
940 /* Find the start of the TLVs and the end of the chunk. This is
941 * the region we search for address parameters.
942 */
943 init = (sctp_init_chunk_t *)skb->data;
944
945 /* Walk the parameters looking for embedded addresses. */
946 sctp_walk_params(params, init, init_hdr.params) {
947
948 /* Note: Ignoring hostname addresses. */
949 af = sctp_get_af_specific(param_type2af(params.p->type));
950 if (!af)
951 continue;
952
953 af->from_addr_param(paddr, params.addr, ntohs(sh->source), 0);
954
955 asoc = __sctp_lookup_association(laddr, paddr, &transport);
956 if (asoc)
957 return asoc;
958 }
959
960 return NULL;
961}
962
963/* Lookup an association for an inbound skb. */
964static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
965 const union sctp_addr *paddr,
966 const union sctp_addr *laddr,
967 struct sctp_transport **transportp)
968{
969 struct sctp_association *asoc;
970
971 asoc = __sctp_lookup_association(laddr, paddr, transportp);
972
973 /* Further lookup for INIT/INIT-ACK packets.
974 * SCTP Implementors Guide, 2.18 Handling of address
975 * parameters within the INIT or INIT-ACK.
976 */
977 if (!asoc)
978 asoc = __sctp_rcv_init_lookup(skb, laddr, transportp);
979
980 return asoc;
981}