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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{
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 struct sk_buff *list = skb_shinfo(skb)->frag_list;
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -030085 struct sctphdr *sh = sctp_hdr(skb);
Harvey Harrison336d3262008-07-18 23:07:09 -070086 __be32 cmp = sh->checksum;
87 __be32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
89 for (; list; list = list->next)
90 val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
91 val);
92
93 val = sctp_end_cksum(val);
94
95 if (val != cmp) {
96 /* CRC failure, dump it. */
97 SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS);
98 return -1;
99 }
100 return 0;
101}
102
David S. Miller79af02c2005-07-08 21:47:49 -0700103struct sctp_input_cb {
104 union {
105 struct inet_skb_parm h4;
106#if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE)
107 struct inet6_skb_parm h6;
108#endif
109 } header;
110 struct sctp_chunk *chunk;
111};
112#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
113
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114/*
115 * This is the routine which IP calls when receiving an SCTP packet.
116 */
117int sctp_rcv(struct sk_buff *skb)
118{
119 struct sock *sk;
120 struct sctp_association *asoc;
121 struct sctp_endpoint *ep = NULL;
122 struct sctp_ep_common *rcvr;
123 struct sctp_transport *transport = NULL;
124 struct sctp_chunk *chunk;
125 struct sctphdr *sh;
126 union sctp_addr src;
127 union sctp_addr dest;
128 int family;
129 struct sctp_af *af;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
131 if (skb->pkt_type!=PACKET_HOST)
132 goto discard_it;
133
134 SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS);
135
Herbert Xu28cd7752006-10-29 23:46:42 -0800136 if (skb_linearize(skb))
137 goto discard_it;
138
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -0300139 sh = sctp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140
141 /* Pull up the IP and SCTP headers. */
Arnaldo Carvalho de Meloea2ae172007-04-25 17:55:53 -0700142 __skb_pull(skb, skb_transport_offset(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 if (skb->len < sizeof(struct sctphdr))
144 goto discard_it;
Herbert Xu60476372007-04-09 11:59:39 -0700145 if (!skb_csum_unnecessary(skb) && 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
Arnaldo Carvalho de Meloeddc9ec2007-04-20 22:47:35 -0700154 family = ipver2af(ip_hdr(skb)->version);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 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
Al Virod55c41b2006-11-20 17:09:40 -0800178 asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport);
Al Viro1c7d1fc2006-11-20 17:08:09 -0800179
Neil Horman0fd9a652005-06-13 15:11:24 -0700180 if (!asoc)
Al Virod55c41b2006-11-20 17:09:40 -0800181 ep = __sctp_rcv_lookup_endpoint(&dest);
Neil Horman0fd9a652005-06-13 15:11:24 -0700182
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 if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
222 goto discard_release;
Patrick McHardyb59c2702006-01-06 23:06:10 -0800223 nf_reset(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
Dmitry Mishinfda9ef52006-08-31 15:28:39 -0700225 if (sk_filter(sk, skb))
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900226 goto discard_release;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227
228 /* Create an SCTP packet structure. */
229 chunk = sctp_chunkify(skb, asoc, sk);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800230 if (!chunk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 goto discard_release;
David S. Miller79af02c2005-07-08 21:47:49 -0700232 SCTP_INPUT_CB(skb)->chunk = chunk;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234 /* Remember what endpoint is to handle this packet. */
235 chunk->rcvr = rcvr;
236
237 /* Remember the SCTP header. */
238 chunk->sctp_hdr = sh;
239
240 /* Set the source and destination addresses of the incoming chunk. */
Al Virod55c41b2006-11-20 17:09:40 -0800241 sctp_init_addrs(chunk, &src, &dest);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242
243 /* Remember where we came from. */
244 chunk->transport = transport;
245
246 /* Acquire access to the sock lock. Note: We are safe from other
247 * bottom halves on this lock, but a user may be in the lock too,
248 * so check if it is busy.
249 */
250 sctp_bh_lock_sock(sk);
251
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700252 if (sock_owned_by_user(sk)) {
253 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700254 sctp_add_backlog(sk, skb);
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700255 } else {
256 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700257 sctp_inq_push(&chunk->rcvr->inqueue, chunk);
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700258 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260 sctp_bh_unlock_sock(sk);
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700261
262 /* Release the asoc/ep ref we took in the lookup calls. */
263 if (asoc)
264 sctp_association_put(asoc);
265 else
266 sctp_endpoint_put(ep);
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800267
Herbert Xu2babf9d2006-03-25 01:25:29 -0800268 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269
270discard_it:
Sridhar Samudralaac0b0462006-08-22 00:15:33 -0700271 SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 kfree_skb(skb);
Herbert Xu2babf9d2006-03-25 01:25:29 -0800273 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
275discard_release:
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700276 /* Release the asoc/ep ref we took in the lookup calls. */
Neil Horman0fd9a652005-06-13 15:11:24 -0700277 if (asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 sctp_association_put(asoc);
Neil Horman0fd9a652005-06-13 15:11:24 -0700279 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 sctp_endpoint_put(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281
282 goto discard_it;
283}
284
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700285/* Process the backlog queue of the socket. Every skb on
286 * the backlog holds a ref on an association or endpoint.
287 * We hold this ref throughout the state machine to make
288 * sure that the structure we need is still around.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 */
290int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
291{
David S. Miller79af02c2005-07-08 21:47:49 -0700292 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900293 struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
294 struct sctp_ep_common *rcvr = NULL;
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700295 int backloged = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900297 rcvr = chunk->rcvr;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800298
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700299 /* If the rcvr is dead then the association or endpoint
300 * has been deleted and we can safely drop the chunk
301 * and refs that we are holding.
302 */
303 if (rcvr->dead) {
304 sctp_chunk_free(chunk);
305 goto done;
306 }
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800307
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700308 if (unlikely(rcvr->sk != sk)) {
309 /* In this case, the association moved from one socket to
310 * another. We are currently sitting on the backlog of the
311 * old socket, so we need to move.
312 * However, since we are here in the process context we
313 * need to take make sure that the user doesn't own
314 * the new socket when we process the packet.
315 * If the new socket is user-owned, queue the chunk to the
316 * backlog of the new socket without dropping any refs.
317 * Otherwise, we can safely push the chunk on the inqueue.
318 */
Sridhar Samudrala7a48f922006-01-17 11:51:28 -0800319
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700320 sk = rcvr->sk;
321 sctp_bh_lock_sock(sk);
322
323 if (sock_owned_by_user(sk)) {
324 sk_add_backlog(sk, skb);
325 backloged = 1;
326 } else
327 sctp_inq_push(inqueue, chunk);
328
329 sctp_bh_unlock_sock(sk);
330
331 /* If the chunk was backloged again, don't drop refs */
332 if (backloged)
333 return 0;
334 } else {
335 sctp_inq_push(inqueue, chunk);
336 }
337
338done:
339 /* Release the refs we took in sctp_add_backlog */
340 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
341 sctp_association_put(sctp_assoc(rcvr));
342 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
343 sctp_endpoint_put(sctp_ep(rcvr));
344 else
345 BUG();
346
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900347 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348}
349
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700350static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800351{
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700352 struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
353 struct sctp_ep_common *rcvr = chunk->rcvr;
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800354
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700355 /* Hold the assoc/ep while hanging on the backlog queue.
356 * This way, we know structures we need will not disappear from us
357 */
358 if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
359 sctp_association_hold(sctp_assoc(rcvr));
360 else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
361 sctp_endpoint_hold(sctp_ep(rcvr));
362 else
363 BUG();
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800364
Vladislav Yasevich61c9fed2006-05-19 11:01:18 -0700365 sk_add_backlog(sk, skb);
Sridhar Samudralac4d24442006-01-17 11:56:26 -0800366}
367
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368/* Handle icmp frag needed error. */
369void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
370 struct sctp_transport *t, __u32 pmtu)
371{
Vlad Yasevich8a479492007-06-07 14:21:05 -0400372 if (!t || (t->pathmtu == pmtu))
Frank Filz52ccb8e2005-12-22 11:36:46 -0800373 return;
374
Vlad Yasevich8a479492007-06-07 14:21:05 -0400375 if (sock_owned_by_user(sk)) {
376 asoc->pmtu_pending = 1;
377 t->pmtu_pending = 1;
378 return;
379 }
380
Frank Filz52ccb8e2005-12-22 11:36:46 -0800381 if (t->param_flags & SPP_PMTUD_ENABLE) {
Vlad Yasevichc910b472007-06-07 13:47:03 -0400382 /* Update transports view of the MTU */
383 sctp_transport_update_pmtu(t, pmtu);
Frank Filz52ccb8e2005-12-22 11:36:46 -0800384
385 /* Update association pmtu. */
386 sctp_assoc_sync_pmtu(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 }
388
Frank Filz52ccb8e2005-12-22 11:36:46 -0800389 /* Retransmit with the new pmtu setting.
390 * Normally, if PMTU discovery is disabled, an ICMP Fragmentation
391 * Needed will never be sent, but if a message was sent before
392 * PMTU discovery was disabled that was larger than the PMTU, it
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900393 * would not be fragmented, so it must be re-transmitted fragmented.
Frank Filz52ccb8e2005-12-22 11:36:46 -0800394 */
395 sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396}
397
398/*
399 * SCTP Implementer's Guide, 2.37 ICMP handling procedures
400 *
401 * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
402 * or a "Protocol Unreachable" treat this message as an abort
403 * with the T bit set.
404 *
405 * This function sends an event to the state machine, which will abort the
406 * association.
407 *
408 */
409void sctp_icmp_proto_unreachable(struct sock *sk,
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900410 struct sctp_association *asoc,
411 struct sctp_transport *t)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412{
Harvey Harrison0dc47872008-03-05 20:47:47 -0800413 SCTP_DEBUG_PRINTK("%s\n", __func__);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414
415 sctp_do_sm(SCTP_EVENT_T_OTHER,
416 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
Frank Filz3f7a87d2005-06-20 13:14:57 -0700417 asoc->state, asoc->ep, asoc, t,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 GFP_ATOMIC);
419
420}
421
422/* Common lookup code for icmp/icmpv6 error handler. */
423struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
424 struct sctphdr *sctphdr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 struct sctp_association **app,
426 struct sctp_transport **tpp)
427{
428 union sctp_addr saddr;
429 union sctp_addr daddr;
430 struct sctp_af *af;
431 struct sock *sk = NULL;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700432 struct sctp_association *asoc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 struct sctp_transport *transport = NULL;
Wei Yongjun7115e632008-06-19 16:07:48 -0700434 struct sctp_init_chunk *chunkhdr;
435 __u32 vtag = ntohl(sctphdr->vtag);
436 int len = skb->len - ((void *)sctphdr - (void *)skb->data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700438 *app = NULL; *tpp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439
440 af = sctp_get_af_specific(family);
441 if (unlikely(!af)) {
442 return NULL;
443 }
444
445 /* Initialize local addresses for lookups. */
446 af->from_skb(&saddr, skb, 1);
447 af->from_skb(&daddr, skb, 0);
448
449 /* Look for an association that matches the incoming ICMP error
450 * packet.
451 */
Al Virod55c41b2006-11-20 17:09:40 -0800452 asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700453 if (!asoc)
454 return NULL;
455
456 sk = asoc->base.sk;
457
Wei Yongjun7115e632008-06-19 16:07:48 -0700458 /* RFC 4960, Appendix C. ICMP Handling
459 *
460 * ICMP6) An implementation MUST validate that the Verification Tag
461 * contained in the ICMP message matches the Verification Tag of
462 * the peer. If the Verification Tag is not 0 and does NOT
463 * match, discard the ICMP message. If it is 0 and the ICMP
464 * message contains enough bytes to verify that the chunk type is
465 * an INIT chunk and that the Initiate Tag matches the tag of the
466 * peer, continue with ICMP7. If the ICMP message is too short
467 * or the chunk type or the Initiate Tag does not match, silently
468 * discard the packet.
469 */
470 if (vtag == 0) {
471 chunkhdr = (struct sctp_init_chunk *)((void *)sctphdr
472 + sizeof(struct sctphdr));
473 if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
474 + sizeof(__be32) ||
475 chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
476 ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) {
477 goto out;
478 }
479 } else if (vtag != asoc->c.peer_vtag) {
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700480 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 }
482
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 sctp_bh_lock_sock(sk);
484
485 /* If too many ICMPs get dropped on busy
486 * servers this needs to be solved differently.
487 */
488 if (sock_owned_by_user(sk))
Pavel Emelyanovde0744a2008-07-16 20:31:16 -0700489 NET_INC_STATS_BH(&init_net, LINUX_MIB_LOCKDROPPEDICMPS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 *app = asoc;
492 *tpp = transport;
493 return sk;
494
495out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 if (asoc)
497 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 return NULL;
499}
500
501/* Common cleanup code for icmp/icmpv6 error handler. */
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700502void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503{
504 sctp_bh_unlock_sock(sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 if (asoc)
506 sctp_association_put(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507}
508
509/*
510 * This routine is called by the ICMP module when it gets some
511 * sort of error condition. If err < 0 then the socket should
512 * be closed and the error returned to the user. If err > 0
513 * it's just the icmp type << 8 | icmp code. After adjustment
514 * header points to the first 8 bytes of the sctp header. We need
515 * to find the appropriate port.
516 *
517 * The locking strategy used here is very "optimistic". When
518 * someone else accesses the socket the ICMP is just dropped
519 * and for some paths there is no check at all.
520 * A more general error queue to queue errors for later handling
521 * is probably better.
522 *
523 */
524void sctp_v4_err(struct sk_buff *skb, __u32 info)
525{
526 struct iphdr *iph = (struct iphdr *)skb->data;
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300527 const int ihlen = iph->ihl * 4;
Arnaldo Carvalho de Melo88c76642007-03-13 14:43:18 -0300528 const int type = icmp_hdr(skb)->type;
529 const int code = icmp_hdr(skb)->code;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 struct sock *sk;
Sridhar Samudrala8de8c872006-05-19 10:58:12 -0700531 struct sctp_association *asoc = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 struct sctp_transport *transport;
533 struct inet_sock *inet;
Arnaldo Carvalho de Melo2e07fa92007-04-10 21:22:35 -0700534 sk_buff_data_t saveip, savesctp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 int err;
536
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300537 if (skb->len < ihlen + 8) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700538 ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 return;
540 }
541
542 /* Fix up skb to look at the embedded net header. */
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700543 saveip = skb->network_header;
544 savesctp = skb->transport_header;
Arnaldo Carvalho de Melo31c77112007-03-10 19:04:55 -0300545 skb_reset_network_header(skb);
Arnaldo Carvalho de Meloa27ef742007-03-13 17:17:10 -0300546 skb_set_transport_header(skb, ihlen);
547 sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
Arnaldo Carvalho de Melo2e07fa92007-04-10 21:22:35 -0700548 /* Put back, the original values. */
Arnaldo Carvalho de Melob0e380b2007-04-10 21:21:55 -0700549 skb->network_header = saveip;
550 skb->transport_header = savesctp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551 if (!sk) {
Pavel Emelyanovdcfc23c2008-07-14 23:03:00 -0700552 ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 return;
554 }
555 /* Warning: The sock lock is held. Remember to call
556 * sctp_err_finish!
557 */
558
559 switch (type) {
560 case ICMP_PARAMETERPROB:
561 err = EPROTO;
562 break;
563 case ICMP_DEST_UNREACH:
564 if (code > NR_ICMP_UNREACH)
565 goto out_unlock;
566
567 /* PMTU discovery (RFC1191) */
568 if (ICMP_FRAG_NEEDED == code) {
569 sctp_icmp_frag_needed(sk, asoc, transport, info);
570 goto out_unlock;
571 }
572 else {
573 if (ICMP_PROT_UNREACH == code) {
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700574 sctp_icmp_proto_unreachable(sk, asoc,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 transport);
576 goto out_unlock;
577 }
578 }
579 err = icmp_err_convert[code].errno;
580 break;
581 case ICMP_TIME_EXCEEDED:
582 /* Ignore any time exceeded errors due to fragment reassembly
583 * timeouts.
584 */
585 if (ICMP_EXC_FRAGTIME == code)
586 goto out_unlock;
587
588 err = EHOSTUNREACH;
589 break;
590 default:
591 goto out_unlock;
592 }
593
594 inet = inet_sk(sk);
595 if (!sock_owned_by_user(sk) && inet->recverr) {
596 sk->sk_err = err;
597 sk->sk_error_report(sk);
598 } else { /* Only an error on timeout */
599 sk->sk_err_soft = err;
600 }
601
602out_unlock:
Sridhar Samudralad1ad1ff2005-07-18 13:44:10 -0700603 sctp_err_finish(sk, asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604}
605
606/*
607 * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
608 *
609 * This function scans all the chunks in the OOTB packet to determine if
610 * the packet should be discarded right away. If a response might be needed
611 * for this packet, or, if further processing is possible, the packet will
612 * be queued to a proper inqueue for the next phase of handling.
613 *
614 * Output:
615 * Return 0 - If further processing is needed.
616 * Return 1 - If the packet can be discarded right away.
617 */
sebastian@breakpoint.cc04675212007-07-26 23:21:31 +0200618static int sctp_rcv_ootb(struct sk_buff *skb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619{
620 sctp_chunkhdr_t *ch;
621 __u8 *ch_end;
622 sctp_errhdr_t *err;
623
624 ch = (sctp_chunkhdr_t *) skb->data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625
626 /* Scan through all the chunks in the packet. */
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800627 do {
628 /* Break out if chunk length is less then minimal. */
629 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
630 break;
631
632 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700633 if (ch_end > skb_tail_pointer(skb))
Tsutomu Fujiia7d1f1b2006-01-17 11:57:09 -0800634 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635
636 /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
637 * receiver MUST silently discard the OOTB packet and take no
638 * further action.
639 */
640 if (SCTP_CID_ABORT == ch->type)
641 goto discard;
642
643 /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
644 * chunk, the receiver should silently discard the packet
645 * and take no further action.
646 */
647 if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
648 goto discard;
649
Vlad Yasevich3c77f962007-09-17 15:14:28 -0400650 /* RFC 4460, 2.11.2
651 * This will discard packets with INIT chunk bundled as
652 * subsequent chunks in the packet. When INIT is first,
653 * the normal INIT processing will discard the chunk.
654 */
655 if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
656 goto discard;
657
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
659 * or a COOKIE ACK the SCTP Packet should be silently
660 * discarded.
661 */
662 if (SCTP_CID_COOKIE_ACK == ch->type)
663 goto discard;
664
665 if (SCTP_CID_ERROR == ch->type) {
666 sctp_walk_errors(err, ch) {
667 if (SCTP_ERROR_STALE_COOKIE == err->cause)
668 goto discard;
669 }
670 }
671
672 ch = (sctp_chunkhdr_t *) ch_end;
Arnaldo Carvalho de Melo27a884d2007-04-19 20:29:13 -0700673 } while (ch_end < skb_tail_pointer(skb));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674
675 return 0;
676
677discard:
678 return 1;
679}
680
681/* Insert endpoint into the hash table. */
682static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
683{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 struct sctp_ep_common *epb;
685 struct sctp_hashbucket *head;
686
687 epb = &ep->base;
688
689 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
690 head = &sctp_ep_hashtable[epb->hashent];
691
692 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500693 hlist_add_head(&epb->node, &head->chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 sctp_write_unlock(&head->lock);
695}
696
697/* Add an endpoint to the hash. Local BH-safe. */
698void sctp_hash_endpoint(struct sctp_endpoint *ep)
699{
700 sctp_local_bh_disable();
701 __sctp_hash_endpoint(ep);
702 sctp_local_bh_enable();
703}
704
705/* Remove endpoint from the hash table. */
706static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
707{
708 struct sctp_hashbucket *head;
709 struct sctp_ep_common *epb;
710
711 epb = &ep->base;
712
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500713 if (hlist_unhashed(&epb->node))
714 return;
715
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716 epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
717
718 head = &sctp_ep_hashtable[epb->hashent];
719
720 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500721 __hlist_del(&epb->node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 sctp_write_unlock(&head->lock);
723}
724
725/* Remove endpoint from the hash. Local BH-safe. */
726void sctp_unhash_endpoint(struct sctp_endpoint *ep)
727{
728 sctp_local_bh_disable();
729 __sctp_unhash_endpoint(ep);
730 sctp_local_bh_enable();
731}
732
733/* Look up an endpoint. */
734static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr)
735{
736 struct sctp_hashbucket *head;
737 struct sctp_ep_common *epb;
738 struct sctp_endpoint *ep;
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500739 struct hlist_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 int hash;
741
Al Viro1c7d1fc2006-11-20 17:08:09 -0800742 hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 head = &sctp_ep_hashtable[hash];
744 read_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500745 sctp_for_each_hentry(epb, node, &head->chain) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 ep = sctp_ep(epb);
747 if (sctp_endpoint_is_match(ep, laddr))
748 goto hit;
749 }
750
751 ep = sctp_sk((sctp_get_ctl_sock()))->ep;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752
753hit:
754 sctp_endpoint_hold(ep);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 read_unlock(&head->lock);
756 return ep;
757}
758
759/* Insert association into the hash table. */
760static void __sctp_hash_established(struct sctp_association *asoc)
761{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 struct sctp_ep_common *epb;
763 struct sctp_hashbucket *head;
764
765 epb = &asoc->base;
766
767 /* Calculate which chain this entry will belong to. */
768 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port);
769
770 head = &sctp_assoc_hashtable[epb->hashent];
771
772 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500773 hlist_add_head(&epb->node, &head->chain);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 sctp_write_unlock(&head->lock);
775}
776
777/* Add an association to the hash. Local BH-safe. */
778void sctp_hash_established(struct sctp_association *asoc)
779{
Vlad Yasevichde76e692006-10-30 18:55:11 -0800780 if (asoc->temp)
781 return;
782
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 sctp_local_bh_disable();
784 __sctp_hash_established(asoc);
785 sctp_local_bh_enable();
786}
787
788/* Remove association from the hash table. */
789static void __sctp_unhash_established(struct sctp_association *asoc)
790{
791 struct sctp_hashbucket *head;
792 struct sctp_ep_common *epb;
793
794 epb = &asoc->base;
795
796 epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port,
797 asoc->peer.port);
798
799 head = &sctp_assoc_hashtable[epb->hashent];
800
801 sctp_write_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500802 __hlist_del(&epb->node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 sctp_write_unlock(&head->lock);
804}
805
806/* Remove association from the hash table. Local BH-safe. */
807void sctp_unhash_established(struct sctp_association *asoc)
808{
Vlad Yasevichde76e692006-10-30 18:55:11 -0800809 if (asoc->temp)
810 return;
811
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 sctp_local_bh_disable();
813 __sctp_unhash_established(asoc);
814 sctp_local_bh_enable();
815}
816
817/* Look up an association. */
818static struct sctp_association *__sctp_lookup_association(
819 const union sctp_addr *local,
820 const union sctp_addr *peer,
821 struct sctp_transport **pt)
822{
823 struct sctp_hashbucket *head;
824 struct sctp_ep_common *epb;
825 struct sctp_association *asoc;
826 struct sctp_transport *transport;
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500827 struct hlist_node *node;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 int hash;
829
830 /* Optimize here for direct hit, only listening connections can
831 * have wildcards anyways.
832 */
Al Viroe2fcced2006-11-20 17:08:41 -0800833 hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 head = &sctp_assoc_hashtable[hash];
835 read_lock(&head->lock);
Vlad Yasevichd970dbf2007-11-09 11:43:40 -0500836 sctp_for_each_hentry(epb, node, &head->chain) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 asoc = sctp_assoc(epb);
838 transport = sctp_assoc_is_match(asoc, local, peer);
839 if (transport)
840 goto hit;
841 }
842
843 read_unlock(&head->lock);
844
845 return NULL;
846
847hit:
848 *pt = transport;
849 sctp_association_hold(asoc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 read_unlock(&head->lock);
851 return asoc;
852}
853
854/* Look up an association. BH-safe. */
855SCTP_STATIC
856struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr,
857 const union sctp_addr *paddr,
858 struct sctp_transport **transportp)
859{
860 struct sctp_association *asoc;
861
862 sctp_local_bh_disable();
863 asoc = __sctp_lookup_association(laddr, paddr, transportp);
864 sctp_local_bh_enable();
865
866 return asoc;
867}
868
869/* Is there an association matching the given local and peer addresses? */
870int sctp_has_association(const union sctp_addr *laddr,
871 const union sctp_addr *paddr)
872{
873 struct sctp_association *asoc;
874 struct sctp_transport *transport;
875
Al Viro6c7be552006-11-20 17:11:50 -0800876 if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 sctp_association_put(asoc);
878 return 1;
879 }
880
881 return 0;
882}
883
884/*
885 * SCTP Implementors Guide, 2.18 Handling of address
886 * parameters within the INIT or INIT-ACK.
887 *
888 * D) When searching for a matching TCB upon reception of an INIT
889 * or INIT-ACK chunk the receiver SHOULD use not only the
890 * source address of the packet (containing the INIT or
891 * INIT-ACK) but the receiver SHOULD also use all valid
892 * address parameters contained within the chunk.
893 *
894 * 2.18.3 Solution description
895 *
896 * This new text clearly specifies to an implementor the need
897 * to look within the INIT or INIT-ACK. Any implementation that
898 * does not do this, may not be able to establish associations
899 * in certain circumstances.
900 *
901 */
902static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
903 const union sctp_addr *laddr, struct sctp_transport **transportp)
904{
905 struct sctp_association *asoc;
906 union sctp_addr addr;
907 union sctp_addr *paddr = &addr;
Arnaldo Carvalho de Melo2c0fd382007-03-13 13:59:32 -0300908 struct sctphdr *sh = sctp_hdr(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909 sctp_chunkhdr_t *ch;
910 union sctp_params params;
911 sctp_init_chunk_t *init;
912 struct sctp_transport *transport;
913 struct sctp_af *af;
914
915 ch = (sctp_chunkhdr_t *) skb->data;
916
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917 /*
918 * This code will NOT touch anything inside the chunk--it is
919 * strictly READ-ONLY.
920 *
921 * RFC 2960 3 SCTP packet Format
922 *
923 * Multiple chunks can be bundled into one SCTP packet up to
924 * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
925 * COMPLETE chunks. These chunks MUST NOT be bundled with any
926 * other chunk in a packet. See Section 6.10 for more details
927 * on chunk bundling.
928 */
929
930 /* Find the start of the TLVs and the end of the chunk. This is
931 * the region we search for address parameters.
932 */
933 init = (sctp_init_chunk_t *)skb->data;
934
935 /* Walk the parameters looking for embedded addresses. */
936 sctp_walk_params(params, init, init_hdr.params) {
937
938 /* Note: Ignoring hostname addresses. */
939 af = sctp_get_af_specific(param_type2af(params.p->type));
940 if (!af)
941 continue;
942
Al Virodd86d132006-11-20 17:11:13 -0800943 af->from_addr_param(paddr, params.addr, sh->source, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944
Al Virodd86d132006-11-20 17:11:13 -0800945 asoc = __sctp_lookup_association(laddr, paddr, &transport);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 if (asoc)
947 return asoc;
948 }
949
950 return NULL;
951}
952
Vlad Yasevichdf218572007-12-20 14:10:38 -0800953/* ADD-IP, Section 5.2
954 * When an endpoint receives an ASCONF Chunk from the remote peer
955 * special procedures may be needed to identify the association the
956 * ASCONF Chunk is associated with. To properly find the association
957 * the following procedures SHOULD be followed:
958 *
959 * D2) If the association is not found, use the address found in the
960 * Address Parameter TLV combined with the port number found in the
961 * SCTP common header. If found proceed to rule D4.
962 *
963 * D2-ext) If more than one ASCONF Chunks are packed together, use the
964 * address found in the ASCONF Address Parameter TLV of each of the
965 * subsequent ASCONF Chunks. If found, proceed to rule D4.
966 */
967static struct sctp_association *__sctp_rcv_asconf_lookup(
968 sctp_chunkhdr_t *ch,
969 const union sctp_addr *laddr,
Al Virobc92dd12008-03-17 22:47:32 -0700970 __be16 peer_port,
Vlad Yasevichdf218572007-12-20 14:10:38 -0800971 struct sctp_transport **transportp)
972{
973 sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch;
974 struct sctp_af *af;
975 union sctp_addr_param *param;
976 union sctp_addr paddr;
977
978 /* Skip over the ADDIP header and find the Address parameter */
979 param = (union sctp_addr_param *)(asconf + 1);
980
981 af = sctp_get_af_specific(param_type2af(param->v4.param_hdr.type));
982 if (unlikely(!af))
983 return NULL;
984
985 af->from_addr_param(&paddr, param, peer_port, 0);
986
987 return __sctp_lookup_association(laddr, &paddr, transportp);
988}
989
990
Vlad Yasevichbbd0d592007-10-03 17:51:34 -0700991/* SCTP-AUTH, Section 6.3:
992* If the receiver does not find a STCB for a packet containing an AUTH
993* chunk as the first chunk and not a COOKIE-ECHO chunk as the second
994* chunk, it MUST use the chunks after the AUTH chunk to look up an existing
995* association.
996*
997* This means that any chunks that can help us identify the association need
998* to be looked at to find this assocation.
Vlad Yasevichbbd0d592007-10-03 17:51:34 -0700999*/
Vlad Yasevichdf218572007-12-20 14:10:38 -08001000static struct sctp_association *__sctp_rcv_walk_lookup(struct sk_buff *skb,
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001001 const union sctp_addr *laddr,
1002 struct sctp_transport **transportp)
1003{
Vlad Yasevichdf218572007-12-20 14:10:38 -08001004 struct sctp_association *asoc = NULL;
1005 sctp_chunkhdr_t *ch;
1006 int have_auth = 0;
1007 unsigned int chunk_num = 1;
1008 __u8 *ch_end;
1009
1010 /* Walk through the chunks looking for AUTH or ASCONF chunks
1011 * to help us find the association.
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001012 */
Vlad Yasevichdf218572007-12-20 14:10:38 -08001013 ch = (sctp_chunkhdr_t *) skb->data;
1014 do {
1015 /* Break out if chunk length is less then minimal. */
1016 if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
1017 break;
1018
1019 ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
1020 if (ch_end > skb_tail_pointer(skb))
1021 break;
1022
1023 switch(ch->type) {
1024 case SCTP_CID_AUTH:
1025 have_auth = chunk_num;
1026 break;
1027
1028 case SCTP_CID_COOKIE_ECHO:
1029 /* If a packet arrives containing an AUTH chunk as
1030 * a first chunk, a COOKIE-ECHO chunk as the second
1031 * chunk, and possibly more chunks after them, and
1032 * the receiver does not have an STCB for that
1033 * packet, then authentication is based on
1034 * the contents of the COOKIE- ECHO chunk.
1035 */
1036 if (have_auth == 1 && chunk_num == 2)
1037 return NULL;
1038 break;
1039
1040 case SCTP_CID_ASCONF:
1041 if (have_auth || sctp_addip_noauth)
1042 asoc = __sctp_rcv_asconf_lookup(ch, laddr,
1043 sctp_hdr(skb)->source,
1044 transportp);
1045 default:
1046 break;
1047 }
1048
1049 if (asoc)
1050 break;
1051
1052 ch = (sctp_chunkhdr_t *) ch_end;
1053 chunk_num++;
1054 } while (ch_end < skb_tail_pointer(skb));
1055
1056 return asoc;
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001057}
1058
1059/*
1060 * There are circumstances when we need to look inside the SCTP packet
1061 * for information to help us find the association. Examples
1062 * include looking inside of INIT/INIT-ACK chunks or after the AUTH
1063 * chunks.
1064 */
1065static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb,
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001066 const union sctp_addr *laddr,
1067 struct sctp_transport **transportp)
1068{
1069 sctp_chunkhdr_t *ch;
1070
1071 ch = (sctp_chunkhdr_t *) skb->data;
1072
Vlad Yasevichdf218572007-12-20 14:10:38 -08001073 /* The code below will attempt to walk the chunk and extract
1074 * parameter information. Before we do that, we need to verify
1075 * that the chunk length doesn't cause overflow. Otherwise, we'll
1076 * walk off the end.
1077 */
1078 if (WORD_ROUND(ntohs(ch->length)) > skb->len)
1079 return NULL;
1080
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001081 /* If this is INIT/INIT-ACK look inside the chunk too. */
1082 switch (ch->type) {
1083 case SCTP_CID_INIT:
1084 case SCTP_CID_INIT_ACK:
1085 return __sctp_rcv_init_lookup(skb, laddr, transportp);
1086 break;
1087
Vlad Yasevichdf218572007-12-20 14:10:38 -08001088 default:
1089 return __sctp_rcv_walk_lookup(skb, laddr, transportp);
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001090 break;
1091 }
1092
Vlad Yasevichdf218572007-12-20 14:10:38 -08001093
Vlad Yasevichbbd0d592007-10-03 17:51:34 -07001094 return NULL;
1095}
1096
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097/* Lookup an association for an inbound skb. */
1098static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
1099 const union sctp_addr *paddr,
1100 const union sctp_addr *laddr,
1101 struct sctp_transport **transportp)
1102{
1103 struct sctp_association *asoc;
1104
1105 asoc = __sctp_lookup_association(laddr, paddr, transportp);
1106
1107 /* Further lookup for INIT/INIT-ACK packets.
1108 * SCTP Implementors Guide, 2.18 Handling of address
1109 * parameters within the INIT or INIT-ACK.
1110 */
1111 if (!asoc)
Vlad Yasevichdf218572007-12-20 14:10:38 -08001112 asoc = __sctp_rcv_lookup_harder(skb, laddr, transportp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113
1114 return asoc;
1115}