Commit | Line | Data |
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60c778b2 | 1 | /* SCTP kernel implementation |
1da177e4 LT |
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 | * | |
60c778b2 | 9 | * This file is part of the SCTP kernel implementation |
1da177e4 LT |
10 | * |
11 | * These functions handle all input from the IP layer into SCTP. | |
12 | * | |
60c778b2 | 13 | * This SCTP implementation is free software; |
1da177e4 LT |
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 | * | |
60c778b2 | 19 | * This SCTP implementation is distributed in the hope that it |
1da177e4 LT |
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 */ | |
5a0e3ad6 | 56 | #include <linux/slab.h> |
1da177e4 LT |
57 | #include <net/ip.h> |
58 | #include <net/icmp.h> | |
59 | #include <net/snmp.h> | |
60 | #include <net/sock.h> | |
61 | #include <net/xfrm.h> | |
62 | #include <net/sctp/sctp.h> | |
63 | #include <net/sctp/sm.h> | |
9ad0977f | 64 | #include <net/sctp/checksum.h> |
dcfc23ca | 65 | #include <net/net_namespace.h> |
1da177e4 LT |
66 | |
67 | /* Forward declarations for internal helpers. */ | |
68 | static int sctp_rcv_ootb(struct sk_buff *); | |
69 | static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, | |
70 | const union sctp_addr *laddr, | |
71 | const union sctp_addr *paddr, | |
72 | struct sctp_transport **transportp); | |
73 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr); | |
74 | static struct sctp_association *__sctp_lookup_association( | |
75 | const union sctp_addr *local, | |
76 | const union sctp_addr *peer, | |
77 | struct sctp_transport **pt); | |
78 | ||
50b1a782 | 79 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb); |
61c9fed4 | 80 | |
1da177e4 LT |
81 | |
82 | /* Calculate the SCTP checksum of an SCTP packet. */ | |
83 | static inline int sctp_rcv_checksum(struct sk_buff *skb) | |
84 | { | |
2c0fd387 | 85 | struct sctphdr *sh = sctp_hdr(skb); |
4458f04c | 86 | __le32 cmp = sh->checksum; |
1b003be3 | 87 | struct sk_buff *list; |
4458f04c VY |
88 | __le32 val; |
89 | __u32 tmp = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); | |
1da177e4 | 90 | |
1b003be3 | 91 | skb_walk_frags(skb, list) |
4458f04c VY |
92 | tmp = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), |
93 | tmp); | |
1da177e4 | 94 | |
4458f04c | 95 | val = sctp_end_cksum(tmp); |
1da177e4 LT |
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 | ||
79af02c2 DM |
105 | struct 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 | ||
1da177e4 LT |
116 | /* |
117 | * This is the routine which IP calls when receiving an SCTP packet. | |
118 | */ | |
119 | int 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; | |
1da177e4 LT |
132 | |
133 | if (skb->pkt_type!=PACKET_HOST) | |
134 | goto discard_it; | |
135 | ||
136 | SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS); | |
137 | ||
28cd7752 HX |
138 | if (skb_linearize(skb)) |
139 | goto discard_it; | |
140 | ||
2c0fd387 | 141 | sh = sctp_hdr(skb); |
1da177e4 LT |
142 | |
143 | /* Pull up the IP and SCTP headers. */ | |
ea2ae17d | 144 | __skb_pull(skb, skb_transport_offset(skb)); |
1da177e4 LT |
145 | if (skb->len < sizeof(struct sctphdr)) |
146 | goto discard_it; | |
06e86806 LN |
147 | if (!sctp_checksum_disable && !skb_csum_unnecessary(skb) && |
148 | sctp_rcv_checksum(skb) < 0) | |
1da177e4 LT |
149 | goto discard_it; |
150 | ||
151 | skb_pull(skb, sizeof(struct sctphdr)); | |
152 | ||
153 | /* Make sure we at least have chunk headers worth of data left. */ | |
154 | if (skb->len < sizeof(struct sctp_chunkhdr)) | |
155 | goto discard_it; | |
156 | ||
eddc9ec5 | 157 | family = ipver2af(ip_hdr(skb)->version); |
1da177e4 LT |
158 | af = sctp_get_af_specific(family); |
159 | if (unlikely(!af)) | |
160 | goto discard_it; | |
161 | ||
162 | /* Initialize local addresses for lookups. */ | |
163 | af->from_skb(&src, skb, 1); | |
164 | af->from_skb(&dest, skb, 0); | |
165 | ||
166 | /* If the packet is to or from a non-unicast address, | |
167 | * silently discard the packet. | |
168 | * | |
169 | * This is not clearly defined in the RFC except in section | |
170 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
171 | * Transmission Protocol" 2.1, "It is important to note that the | |
172 | * IP address of an SCTP transport address must be a routable | |
173 | * unicast address. In other words, IP multicast addresses and | |
174 | * IP broadcast addresses cannot be used in an SCTP transport | |
175 | * address." | |
176 | */ | |
5636bef7 VY |
177 | if (!af->addr_valid(&src, NULL, skb) || |
178 | !af->addr_valid(&dest, NULL, skb)) | |
1da177e4 LT |
179 | goto discard_it; |
180 | ||
d55c41b1 | 181 | asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport); |
1c7d1fc1 | 182 | |
0fd9a65a | 183 | if (!asoc) |
d55c41b1 | 184 | ep = __sctp_rcv_lookup_endpoint(&dest); |
0fd9a65a NH |
185 | |
186 | /* Retrieve the common input handling substructure. */ | |
187 | rcvr = asoc ? &asoc->base : &ep->base; | |
188 | sk = rcvr->sk; | |
189 | ||
190 | /* | |
191 | * If a frame arrives on an interface and the receiving socket is | |
192 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
193 | */ | |
194 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) | |
195 | { | |
0fd9a65a NH |
196 | if (asoc) { |
197 | sctp_association_put(asoc); | |
198 | asoc = NULL; | |
199 | } else { | |
200 | sctp_endpoint_put(ep); | |
201 | ep = NULL; | |
202 | } | |
203 | sk = sctp_get_ctl_sock(); | |
204 | ep = sctp_sk(sk)->ep; | |
205 | sctp_endpoint_hold(ep); | |
0fd9a65a NH |
206 | rcvr = &ep->base; |
207 | } | |
208 | ||
1da177e4 LT |
209 | /* |
210 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
211 | * An SCTP packet is called an "out of the blue" (OOTB) | |
212 | * packet if it is correctly formed, i.e., passed the | |
213 | * receiver's checksum check, but the receiver is not | |
214 | * able to identify the association to which this | |
215 | * packet belongs. | |
216 | */ | |
217 | if (!asoc) { | |
1da177e4 LT |
218 | if (sctp_rcv_ootb(skb)) { |
219 | SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES); | |
220 | goto discard_release; | |
221 | } | |
222 | } | |
223 | ||
1da177e4 LT |
224 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
225 | goto discard_release; | |
b59c2701 | 226 | nf_reset(skb); |
1da177e4 | 227 | |
fda9ef5d | 228 | if (sk_filter(sk, skb)) |
d808ad9a | 229 | goto discard_release; |
1da177e4 LT |
230 | |
231 | /* Create an SCTP packet structure. */ | |
232 | chunk = sctp_chunkify(skb, asoc, sk); | |
2babf9da | 233 | if (!chunk) |
1da177e4 | 234 | goto discard_release; |
79af02c2 | 235 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 236 | |
1da177e4 LT |
237 | /* Remember what endpoint is to handle this packet. */ |
238 | chunk->rcvr = rcvr; | |
239 | ||
240 | /* Remember the SCTP header. */ | |
241 | chunk->sctp_hdr = sh; | |
242 | ||
243 | /* Set the source and destination addresses of the incoming chunk. */ | |
d55c41b1 | 244 | sctp_init_addrs(chunk, &src, &dest); |
1da177e4 LT |
245 | |
246 | /* Remember where we came from. */ | |
247 | chunk->transport = transport; | |
248 | ||
249 | /* Acquire access to the sock lock. Note: We are safe from other | |
250 | * bottom halves on this lock, but a user may be in the lock too, | |
251 | * so check if it is busy. | |
252 | */ | |
253 | sctp_bh_lock_sock(sk); | |
254 | ||
ae53b5bd VY |
255 | if (sk != rcvr->sk) { |
256 | /* Our cached sk is different from the rcvr->sk. This is | |
257 | * because migrate()/accept() may have moved the association | |
258 | * to a new socket and released all the sockets. So now we | |
259 | * are holding a lock on the old socket while the user may | |
260 | * be doing something with the new socket. Switch our veiw | |
261 | * of the current sk. | |
262 | */ | |
263 | sctp_bh_unlock_sock(sk); | |
264 | sk = rcvr->sk; | |
265 | sctp_bh_lock_sock(sk); | |
266 | } | |
267 | ||
ac0b0462 | 268 | if (sock_owned_by_user(sk)) { |
50b1a782 ZY |
269 | if (sctp_add_backlog(sk, skb)) { |
270 | sctp_bh_unlock_sock(sk); | |
271 | sctp_chunk_free(chunk); | |
272 | skb = NULL; /* sctp_chunk_free already freed the skb */ | |
273 | goto discard_release; | |
274 | } | |
ac0b0462 | 275 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG); |
ac0b0462 SS |
276 | } else { |
277 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ); | |
61c9fed4 | 278 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 279 | } |
1da177e4 | 280 | |
1da177e4 | 281 | sctp_bh_unlock_sock(sk); |
61c9fed4 VY |
282 | |
283 | /* Release the asoc/ep ref we took in the lookup calls. */ | |
284 | if (asoc) | |
285 | sctp_association_put(asoc); | |
286 | else | |
287 | sctp_endpoint_put(ep); | |
7a48f923 | 288 | |
2babf9da | 289 | return 0; |
1da177e4 LT |
290 | |
291 | discard_it: | |
ac0b0462 | 292 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS); |
1da177e4 | 293 | kfree_skb(skb); |
2babf9da | 294 | return 0; |
1da177e4 LT |
295 | |
296 | discard_release: | |
61c9fed4 | 297 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 298 | if (asoc) |
1da177e4 | 299 | sctp_association_put(asoc); |
0fd9a65a | 300 | else |
1da177e4 | 301 | sctp_endpoint_put(ep); |
1da177e4 LT |
302 | |
303 | goto discard_it; | |
304 | } | |
305 | ||
61c9fed4 VY |
306 | /* Process the backlog queue of the socket. Every skb on |
307 | * the backlog holds a ref on an association or endpoint. | |
308 | * We hold this ref throughout the state machine to make | |
309 | * sure that the structure we need is still around. | |
1da177e4 LT |
310 | */ |
311 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
312 | { | |
79af02c2 | 313 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
d808ad9a YH |
314 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
315 | struct sctp_ep_common *rcvr = NULL; | |
61c9fed4 | 316 | int backloged = 0; |
7a48f923 | 317 | |
d808ad9a | 318 | rcvr = chunk->rcvr; |
c4d2444e | 319 | |
61c9fed4 VY |
320 | /* If the rcvr is dead then the association or endpoint |
321 | * has been deleted and we can safely drop the chunk | |
322 | * and refs that we are holding. | |
323 | */ | |
324 | if (rcvr->dead) { | |
325 | sctp_chunk_free(chunk); | |
326 | goto done; | |
327 | } | |
328 | ||
329 | if (unlikely(rcvr->sk != sk)) { | |
330 | /* In this case, the association moved from one socket to | |
331 | * another. We are currently sitting on the backlog of the | |
332 | * old socket, so we need to move. | |
333 | * However, since we are here in the process context we | |
334 | * need to take make sure that the user doesn't own | |
335 | * the new socket when we process the packet. | |
336 | * If the new socket is user-owned, queue the chunk to the | |
337 | * backlog of the new socket without dropping any refs. | |
338 | * Otherwise, we can safely push the chunk on the inqueue. | |
339 | */ | |
340 | ||
341 | sk = rcvr->sk; | |
342 | sctp_bh_lock_sock(sk); | |
343 | ||
344 | if (sock_owned_by_user(sk)) { | |
a3a858ff | 345 | if (sk_add_backlog(sk, skb)) |
50b1a782 ZY |
346 | sctp_chunk_free(chunk); |
347 | else | |
348 | backloged = 1; | |
61c9fed4 VY |
349 | } else |
350 | sctp_inq_push(inqueue, chunk); | |
351 | ||
352 | sctp_bh_unlock_sock(sk); | |
353 | ||
354 | /* If the chunk was backloged again, don't drop refs */ | |
355 | if (backloged) | |
356 | return 0; | |
357 | } else { | |
358 | sctp_inq_push(inqueue, chunk); | |
359 | } | |
360 | ||
361 | done: | |
362 | /* Release the refs we took in sctp_add_backlog */ | |
363 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
364 | sctp_association_put(sctp_assoc(rcvr)); | |
365 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
366 | sctp_endpoint_put(sctp_ep(rcvr)); | |
367 | else | |
368 | BUG(); | |
369 | ||
d808ad9a | 370 | return 0; |
1da177e4 LT |
371 | } |
372 | ||
50b1a782 | 373 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 374 | { |
61c9fed4 VY |
375 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
376 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
50b1a782 | 377 | int ret; |
c4d2444e | 378 | |
a3a858ff | 379 | ret = sk_add_backlog(sk, skb); |
50b1a782 ZY |
380 | if (!ret) { |
381 | /* Hold the assoc/ep while hanging on the backlog queue. | |
382 | * This way, we know structures we need will not disappear | |
383 | * from us | |
384 | */ | |
385 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
386 | sctp_association_hold(sctp_assoc(rcvr)); | |
387 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
388 | sctp_endpoint_hold(sctp_ep(rcvr)); | |
389 | else | |
390 | BUG(); | |
391 | } | |
392 | return ret; | |
61c9fed4 | 393 | |
c4d2444e SS |
394 | } |
395 | ||
1da177e4 LT |
396 | /* Handle icmp frag needed error. */ |
397 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
398 | struct sctp_transport *t, __u32 pmtu) | |
399 | { | |
91bd6b1e | 400 | if (!t || (t->pathmtu <= pmtu)) |
52ccb8e9 FF |
401 | return; |
402 | ||
8a479491 VY |
403 | if (sock_owned_by_user(sk)) { |
404 | asoc->pmtu_pending = 1; | |
405 | t->pmtu_pending = 1; | |
406 | return; | |
407 | } | |
408 | ||
52ccb8e9 | 409 | if (t->param_flags & SPP_PMTUD_ENABLE) { |
c910b47e VY |
410 | /* Update transports view of the MTU */ |
411 | sctp_transport_update_pmtu(t, pmtu); | |
1da177e4 | 412 | |
52ccb8e9 | 413 | /* Update association pmtu. */ |
1da177e4 | 414 | sctp_assoc_sync_pmtu(asoc); |
1da177e4 | 415 | } |
52ccb8e9 FF |
416 | |
417 | /* Retransmit with the new pmtu setting. | |
418 | * Normally, if PMTU discovery is disabled, an ICMP Fragmentation | |
419 | * Needed will never be sent, but if a message was sent before | |
420 | * PMTU discovery was disabled that was larger than the PMTU, it | |
d808ad9a | 421 | * would not be fragmented, so it must be re-transmitted fragmented. |
52ccb8e9 FF |
422 | */ |
423 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
424 | } |
425 | ||
426 | /* | |
427 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
428 | * | |
429 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
430 | * or a "Protocol Unreachable" treat this message as an abort | |
431 | * with the T bit set. | |
432 | * | |
433 | * This function sends an event to the state machine, which will abort the | |
434 | * association. | |
435 | * | |
436 | */ | |
437 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
d808ad9a YH |
438 | struct sctp_association *asoc, |
439 | struct sctp_transport *t) | |
1da177e4 | 440 | { |
0dc47877 | 441 | SCTP_DEBUG_PRINTK("%s\n", __func__); |
1da177e4 | 442 | |
50b5d6ad VY |
443 | if (sock_owned_by_user(sk)) { |
444 | if (timer_pending(&t->proto_unreach_timer)) | |
445 | return; | |
446 | else { | |
447 | if (!mod_timer(&t->proto_unreach_timer, | |
448 | jiffies + (HZ/20))) | |
449 | sctp_association_hold(asoc); | |
450 | } | |
451 | ||
452 | } else { | |
453 | if (timer_pending(&t->proto_unreach_timer) && | |
454 | del_timer(&t->proto_unreach_timer)) | |
455 | sctp_association_put(asoc); | |
1da177e4 | 456 | |
50b5d6ad VY |
457 | sctp_do_sm(SCTP_EVENT_T_OTHER, |
458 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), | |
459 | asoc->state, asoc->ep, asoc, t, | |
460 | GFP_ATOMIC); | |
461 | } | |
1da177e4 LT |
462 | } |
463 | ||
464 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
465 | struct sock *sctp_err_lookup(int family, struct sk_buff *skb, | |
466 | struct sctphdr *sctphdr, | |
1da177e4 LT |
467 | struct sctp_association **app, |
468 | struct sctp_transport **tpp) | |
469 | { | |
470 | union sctp_addr saddr; | |
471 | union sctp_addr daddr; | |
472 | struct sctp_af *af; | |
473 | struct sock *sk = NULL; | |
8de8c873 | 474 | struct sctp_association *asoc; |
1da177e4 | 475 | struct sctp_transport *transport = NULL; |
7115e632 WY |
476 | struct sctp_init_chunk *chunkhdr; |
477 | __u32 vtag = ntohl(sctphdr->vtag); | |
478 | int len = skb->len - ((void *)sctphdr - (void *)skb->data); | |
1da177e4 | 479 | |
d1ad1ff2 | 480 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
481 | |
482 | af = sctp_get_af_specific(family); | |
483 | if (unlikely(!af)) { | |
484 | return NULL; | |
485 | } | |
486 | ||
487 | /* Initialize local addresses for lookups. */ | |
488 | af->from_skb(&saddr, skb, 1); | |
489 | af->from_skb(&daddr, skb, 0); | |
490 | ||
491 | /* Look for an association that matches the incoming ICMP error | |
492 | * packet. | |
493 | */ | |
d55c41b1 | 494 | asoc = __sctp_lookup_association(&saddr, &daddr, &transport); |
d1ad1ff2 SS |
495 | if (!asoc) |
496 | return NULL; | |
1da177e4 | 497 | |
d1ad1ff2 | 498 | sk = asoc->base.sk; |
1da177e4 | 499 | |
7115e632 WY |
500 | /* RFC 4960, Appendix C. ICMP Handling |
501 | * | |
502 | * ICMP6) An implementation MUST validate that the Verification Tag | |
503 | * contained in the ICMP message matches the Verification Tag of | |
504 | * the peer. If the Verification Tag is not 0 and does NOT | |
505 | * match, discard the ICMP message. If it is 0 and the ICMP | |
506 | * message contains enough bytes to verify that the chunk type is | |
507 | * an INIT chunk and that the Initiate Tag matches the tag of the | |
508 | * peer, continue with ICMP7. If the ICMP message is too short | |
509 | * or the chunk type or the Initiate Tag does not match, silently | |
510 | * discard the packet. | |
511 | */ | |
512 | if (vtag == 0) { | |
513 | chunkhdr = (struct sctp_init_chunk *)((void *)sctphdr | |
514 | + sizeof(struct sctphdr)); | |
515 | if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t) | |
516 | + sizeof(__be32) || | |
517 | chunkhdr->chunk_hdr.type != SCTP_CID_INIT || | |
518 | ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) { | |
519 | goto out; | |
520 | } | |
521 | } else if (vtag != asoc->c.peer_vtag) { | |
d1ad1ff2 SS |
522 | goto out; |
523 | } | |
1da177e4 LT |
524 | |
525 | sctp_bh_lock_sock(sk); | |
526 | ||
527 | /* If too many ICMPs get dropped on busy | |
528 | * servers this needs to be solved differently. | |
529 | */ | |
530 | if (sock_owned_by_user(sk)) | |
de0744af | 531 | NET_INC_STATS_BH(&init_net, LINUX_MIB_LOCKDROPPEDICMPS); |
1da177e4 | 532 | |
1da177e4 LT |
533 | *app = asoc; |
534 | *tpp = transport; | |
535 | return sk; | |
536 | ||
537 | out: | |
1da177e4 LT |
538 | if (asoc) |
539 | sctp_association_put(asoc); | |
1da177e4 LT |
540 | return NULL; |
541 | } | |
542 | ||
543 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 544 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
545 | { |
546 | sctp_bh_unlock_sock(sk); | |
1da177e4 LT |
547 | if (asoc) |
548 | sctp_association_put(asoc); | |
1da177e4 LT |
549 | } |
550 | ||
551 | /* | |
552 | * This routine is called by the ICMP module when it gets some | |
553 | * sort of error condition. If err < 0 then the socket should | |
554 | * be closed and the error returned to the user. If err > 0 | |
555 | * it's just the icmp type << 8 | icmp code. After adjustment | |
556 | * header points to the first 8 bytes of the sctp header. We need | |
557 | * to find the appropriate port. | |
558 | * | |
559 | * The locking strategy used here is very "optimistic". When | |
560 | * someone else accesses the socket the ICMP is just dropped | |
561 | * and for some paths there is no check at all. | |
562 | * A more general error queue to queue errors for later handling | |
563 | * is probably better. | |
564 | * | |
565 | */ | |
566 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
567 | { | |
568 | struct iphdr *iph = (struct iphdr *)skb->data; | |
a27ef749 | 569 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
570 | const int type = icmp_hdr(skb)->type; |
571 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 572 | struct sock *sk; |
8de8c873 | 573 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
574 | struct sctp_transport *transport; |
575 | struct inet_sock *inet; | |
2e07fa9c | 576 | sk_buff_data_t saveip, savesctp; |
1da177e4 LT |
577 | int err; |
578 | ||
a27ef749 | 579 | if (skb->len < ihlen + 8) { |
dcfc23ca | 580 | ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS); |
1da177e4 LT |
581 | return; |
582 | } | |
583 | ||
584 | /* Fix up skb to look at the embedded net header. */ | |
b0e380b1 ACM |
585 | saveip = skb->network_header; |
586 | savesctp = skb->transport_header; | |
31c7711b | 587 | skb_reset_network_header(skb); |
a27ef749 ACM |
588 | skb_set_transport_header(skb, ihlen); |
589 | sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport); | |
2e07fa9c | 590 | /* Put back, the original values. */ |
b0e380b1 ACM |
591 | skb->network_header = saveip; |
592 | skb->transport_header = savesctp; | |
1da177e4 | 593 | if (!sk) { |
dcfc23ca | 594 | ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS); |
1da177e4 LT |
595 | return; |
596 | } | |
597 | /* Warning: The sock lock is held. Remember to call | |
598 | * sctp_err_finish! | |
599 | */ | |
600 | ||
601 | switch (type) { | |
602 | case ICMP_PARAMETERPROB: | |
603 | err = EPROTO; | |
604 | break; | |
605 | case ICMP_DEST_UNREACH: | |
606 | if (code > NR_ICMP_UNREACH) | |
607 | goto out_unlock; | |
608 | ||
609 | /* PMTU discovery (RFC1191) */ | |
610 | if (ICMP_FRAG_NEEDED == code) { | |
611 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
612 | goto out_unlock; | |
613 | } | |
614 | else { | |
615 | if (ICMP_PROT_UNREACH == code) { | |
d1ad1ff2 | 616 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
617 | transport); |
618 | goto out_unlock; | |
619 | } | |
620 | } | |
621 | err = icmp_err_convert[code].errno; | |
622 | break; | |
623 | case ICMP_TIME_EXCEEDED: | |
624 | /* Ignore any time exceeded errors due to fragment reassembly | |
625 | * timeouts. | |
626 | */ | |
627 | if (ICMP_EXC_FRAGTIME == code) | |
628 | goto out_unlock; | |
629 | ||
630 | err = EHOSTUNREACH; | |
631 | break; | |
632 | default: | |
633 | goto out_unlock; | |
634 | } | |
635 | ||
636 | inet = inet_sk(sk); | |
637 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
638 | sk->sk_err = err; | |
639 | sk->sk_error_report(sk); | |
640 | } else { /* Only an error on timeout */ | |
641 | sk->sk_err_soft = err; | |
642 | } | |
643 | ||
644 | out_unlock: | |
d1ad1ff2 | 645 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
646 | } |
647 | ||
648 | /* | |
649 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
650 | * | |
651 | * This function scans all the chunks in the OOTB packet to determine if | |
652 | * the packet should be discarded right away. If a response might be needed | |
653 | * for this packet, or, if further processing is possible, the packet will | |
654 | * be queued to a proper inqueue for the next phase of handling. | |
655 | * | |
656 | * Output: | |
657 | * Return 0 - If further processing is needed. | |
658 | * Return 1 - If the packet can be discarded right away. | |
659 | */ | |
04675210 | 660 | static int sctp_rcv_ootb(struct sk_buff *skb) |
1da177e4 LT |
661 | { |
662 | sctp_chunkhdr_t *ch; | |
663 | __u8 *ch_end; | |
664 | sctp_errhdr_t *err; | |
665 | ||
666 | ch = (sctp_chunkhdr_t *) skb->data; | |
1da177e4 LT |
667 | |
668 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 TF |
669 | do { |
670 | /* Break out if chunk length is less then minimal. */ | |
671 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
672 | break; | |
673 | ||
674 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
27a884dc | 675 | if (ch_end > skb_tail_pointer(skb)) |
a7d1f1b6 | 676 | break; |
1da177e4 LT |
677 | |
678 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
679 | * receiver MUST silently discard the OOTB packet and take no | |
680 | * further action. | |
681 | */ | |
682 | if (SCTP_CID_ABORT == ch->type) | |
683 | goto discard; | |
684 | ||
685 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
686 | * chunk, the receiver should silently discard the packet | |
687 | * and take no further action. | |
688 | */ | |
689 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
690 | goto discard; | |
691 | ||
3c77f961 VY |
692 | /* RFC 4460, 2.11.2 |
693 | * This will discard packets with INIT chunk bundled as | |
694 | * subsequent chunks in the packet. When INIT is first, | |
695 | * the normal INIT processing will discard the chunk. | |
696 | */ | |
697 | if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data) | |
698 | goto discard; | |
699 | ||
1da177e4 LT |
700 | /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR |
701 | * or a COOKIE ACK the SCTP Packet should be silently | |
702 | * discarded. | |
703 | */ | |
704 | if (SCTP_CID_COOKIE_ACK == ch->type) | |
705 | goto discard; | |
706 | ||
707 | if (SCTP_CID_ERROR == ch->type) { | |
708 | sctp_walk_errors(err, ch) { | |
709 | if (SCTP_ERROR_STALE_COOKIE == err->cause) | |
710 | goto discard; | |
711 | } | |
712 | } | |
713 | ||
714 | ch = (sctp_chunkhdr_t *) ch_end; | |
27a884dc | 715 | } while (ch_end < skb_tail_pointer(skb)); |
1da177e4 LT |
716 | |
717 | return 0; | |
718 | ||
719 | discard: | |
720 | return 1; | |
721 | } | |
722 | ||
723 | /* Insert endpoint into the hash table. */ | |
724 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
725 | { | |
1da177e4 LT |
726 | struct sctp_ep_common *epb; |
727 | struct sctp_hashbucket *head; | |
728 | ||
729 | epb = &ep->base; | |
730 | ||
731 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
732 | head = &sctp_ep_hashtable[epb->hashent]; | |
733 | ||
734 | sctp_write_lock(&head->lock); | |
d970dbf8 | 735 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
736 | sctp_write_unlock(&head->lock); |
737 | } | |
738 | ||
739 | /* Add an endpoint to the hash. Local BH-safe. */ | |
740 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
741 | { | |
742 | sctp_local_bh_disable(); | |
743 | __sctp_hash_endpoint(ep); | |
744 | sctp_local_bh_enable(); | |
745 | } | |
746 | ||
747 | /* Remove endpoint from the hash table. */ | |
748 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
749 | { | |
750 | struct sctp_hashbucket *head; | |
751 | struct sctp_ep_common *epb; | |
752 | ||
753 | epb = &ep->base; | |
754 | ||
d970dbf8 VY |
755 | if (hlist_unhashed(&epb->node)) |
756 | return; | |
757 | ||
1da177e4 LT |
758 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); |
759 | ||
760 | head = &sctp_ep_hashtable[epb->hashent]; | |
761 | ||
762 | sctp_write_lock(&head->lock); | |
d970dbf8 | 763 | __hlist_del(&epb->node); |
1da177e4 LT |
764 | sctp_write_unlock(&head->lock); |
765 | } | |
766 | ||
767 | /* Remove endpoint from the hash. Local BH-safe. */ | |
768 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
769 | { | |
770 | sctp_local_bh_disable(); | |
771 | __sctp_unhash_endpoint(ep); | |
772 | sctp_local_bh_enable(); | |
773 | } | |
774 | ||
775 | /* Look up an endpoint. */ | |
776 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr) | |
777 | { | |
778 | struct sctp_hashbucket *head; | |
779 | struct sctp_ep_common *epb; | |
780 | struct sctp_endpoint *ep; | |
d970dbf8 | 781 | struct hlist_node *node; |
1da177e4 LT |
782 | int hash; |
783 | ||
1c7d1fc1 | 784 | hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
785 | head = &sctp_ep_hashtable[hash]; |
786 | read_lock(&head->lock); | |
d970dbf8 | 787 | sctp_for_each_hentry(epb, node, &head->chain) { |
1da177e4 LT |
788 | ep = sctp_ep(epb); |
789 | if (sctp_endpoint_is_match(ep, laddr)) | |
790 | goto hit; | |
791 | } | |
792 | ||
793 | ep = sctp_sk((sctp_get_ctl_sock()))->ep; | |
1da177e4 LT |
794 | |
795 | hit: | |
796 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
797 | read_unlock(&head->lock); |
798 | return ep; | |
799 | } | |
800 | ||
801 | /* Insert association into the hash table. */ | |
802 | static void __sctp_hash_established(struct sctp_association *asoc) | |
803 | { | |
1da177e4 LT |
804 | struct sctp_ep_common *epb; |
805 | struct sctp_hashbucket *head; | |
806 | ||
807 | epb = &asoc->base; | |
808 | ||
809 | /* Calculate which chain this entry will belong to. */ | |
810 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port); | |
811 | ||
812 | head = &sctp_assoc_hashtable[epb->hashent]; | |
813 | ||
814 | sctp_write_lock(&head->lock); | |
d970dbf8 | 815 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
816 | sctp_write_unlock(&head->lock); |
817 | } | |
818 | ||
819 | /* Add an association to the hash. Local BH-safe. */ | |
820 | void sctp_hash_established(struct sctp_association *asoc) | |
821 | { | |
de76e695 VY |
822 | if (asoc->temp) |
823 | return; | |
824 | ||
1da177e4 LT |
825 | sctp_local_bh_disable(); |
826 | __sctp_hash_established(asoc); | |
827 | sctp_local_bh_enable(); | |
828 | } | |
829 | ||
830 | /* Remove association from the hash table. */ | |
831 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
832 | { | |
833 | struct sctp_hashbucket *head; | |
834 | struct sctp_ep_common *epb; | |
835 | ||
836 | epb = &asoc->base; | |
837 | ||
838 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, | |
839 | asoc->peer.port); | |
840 | ||
841 | head = &sctp_assoc_hashtable[epb->hashent]; | |
842 | ||
843 | sctp_write_lock(&head->lock); | |
d970dbf8 | 844 | __hlist_del(&epb->node); |
1da177e4 LT |
845 | sctp_write_unlock(&head->lock); |
846 | } | |
847 | ||
848 | /* Remove association from the hash table. Local BH-safe. */ | |
849 | void sctp_unhash_established(struct sctp_association *asoc) | |
850 | { | |
de76e695 VY |
851 | if (asoc->temp) |
852 | return; | |
853 | ||
1da177e4 LT |
854 | sctp_local_bh_disable(); |
855 | __sctp_unhash_established(asoc); | |
856 | sctp_local_bh_enable(); | |
857 | } | |
858 | ||
859 | /* Look up an association. */ | |
860 | static struct sctp_association *__sctp_lookup_association( | |
861 | const union sctp_addr *local, | |
862 | const union sctp_addr *peer, | |
863 | struct sctp_transport **pt) | |
864 | { | |
865 | struct sctp_hashbucket *head; | |
866 | struct sctp_ep_common *epb; | |
867 | struct sctp_association *asoc; | |
868 | struct sctp_transport *transport; | |
d970dbf8 | 869 | struct hlist_node *node; |
1da177e4 LT |
870 | int hash; |
871 | ||
872 | /* Optimize here for direct hit, only listening connections can | |
873 | * have wildcards anyways. | |
874 | */ | |
e2fccedb | 875 | hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port)); |
1da177e4 LT |
876 | head = &sctp_assoc_hashtable[hash]; |
877 | read_lock(&head->lock); | |
d970dbf8 | 878 | sctp_for_each_hentry(epb, node, &head->chain) { |
1da177e4 LT |
879 | asoc = sctp_assoc(epb); |
880 | transport = sctp_assoc_is_match(asoc, local, peer); | |
881 | if (transport) | |
882 | goto hit; | |
883 | } | |
884 | ||
885 | read_unlock(&head->lock); | |
886 | ||
887 | return NULL; | |
888 | ||
889 | hit: | |
890 | *pt = transport; | |
891 | sctp_association_hold(asoc); | |
1da177e4 LT |
892 | read_unlock(&head->lock); |
893 | return asoc; | |
894 | } | |
895 | ||
896 | /* Look up an association. BH-safe. */ | |
897 | SCTP_STATIC | |
898 | struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr, | |
899 | const union sctp_addr *paddr, | |
900 | struct sctp_transport **transportp) | |
901 | { | |
902 | struct sctp_association *asoc; | |
903 | ||
904 | sctp_local_bh_disable(); | |
905 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
906 | sctp_local_bh_enable(); | |
907 | ||
908 | return asoc; | |
909 | } | |
910 | ||
911 | /* Is there an association matching the given local and peer addresses? */ | |
912 | int sctp_has_association(const union sctp_addr *laddr, | |
913 | const union sctp_addr *paddr) | |
914 | { | |
915 | struct sctp_association *asoc; | |
916 | struct sctp_transport *transport; | |
917 | ||
6c7be55c | 918 | if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) { |
1da177e4 LT |
919 | sctp_association_put(asoc); |
920 | return 1; | |
921 | } | |
922 | ||
923 | return 0; | |
924 | } | |
925 | ||
926 | /* | |
927 | * SCTP Implementors Guide, 2.18 Handling of address | |
928 | * parameters within the INIT or INIT-ACK. | |
929 | * | |
930 | * D) When searching for a matching TCB upon reception of an INIT | |
931 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
932 | * source address of the packet (containing the INIT or | |
933 | * INIT-ACK) but the receiver SHOULD also use all valid | |
934 | * address parameters contained within the chunk. | |
935 | * | |
936 | * 2.18.3 Solution description | |
937 | * | |
938 | * This new text clearly specifies to an implementor the need | |
939 | * to look within the INIT or INIT-ACK. Any implementation that | |
940 | * does not do this, may not be able to establish associations | |
941 | * in certain circumstances. | |
942 | * | |
943 | */ | |
944 | static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, | |
945 | const union sctp_addr *laddr, struct sctp_transport **transportp) | |
946 | { | |
947 | struct sctp_association *asoc; | |
948 | union sctp_addr addr; | |
949 | union sctp_addr *paddr = &addr; | |
2c0fd387 | 950 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
951 | sctp_chunkhdr_t *ch; |
952 | union sctp_params params; | |
953 | sctp_init_chunk_t *init; | |
954 | struct sctp_transport *transport; | |
955 | struct sctp_af *af; | |
956 | ||
957 | ch = (sctp_chunkhdr_t *) skb->data; | |
958 | ||
1da177e4 LT |
959 | /* |
960 | * This code will NOT touch anything inside the chunk--it is | |
961 | * strictly READ-ONLY. | |
962 | * | |
963 | * RFC 2960 3 SCTP packet Format | |
964 | * | |
965 | * Multiple chunks can be bundled into one SCTP packet up to | |
966 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
967 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
968 | * other chunk in a packet. See Section 6.10 for more details | |
969 | * on chunk bundling. | |
970 | */ | |
971 | ||
972 | /* Find the start of the TLVs and the end of the chunk. This is | |
973 | * the region we search for address parameters. | |
974 | */ | |
975 | init = (sctp_init_chunk_t *)skb->data; | |
976 | ||
977 | /* Walk the parameters looking for embedded addresses. */ | |
978 | sctp_walk_params(params, init, init_hdr.params) { | |
979 | ||
980 | /* Note: Ignoring hostname addresses. */ | |
981 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
982 | if (!af) | |
983 | continue; | |
984 | ||
dd86d136 | 985 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 986 | |
dd86d136 | 987 | asoc = __sctp_lookup_association(laddr, paddr, &transport); |
1da177e4 LT |
988 | if (asoc) |
989 | return asoc; | |
990 | } | |
991 | ||
992 | return NULL; | |
993 | } | |
994 | ||
df218577 VY |
995 | /* ADD-IP, Section 5.2 |
996 | * When an endpoint receives an ASCONF Chunk from the remote peer | |
997 | * special procedures may be needed to identify the association the | |
998 | * ASCONF Chunk is associated with. To properly find the association | |
999 | * the following procedures SHOULD be followed: | |
1000 | * | |
1001 | * D2) If the association is not found, use the address found in the | |
1002 | * Address Parameter TLV combined with the port number found in the | |
1003 | * SCTP common header. If found proceed to rule D4. | |
1004 | * | |
1005 | * D2-ext) If more than one ASCONF Chunks are packed together, use the | |
1006 | * address found in the ASCONF Address Parameter TLV of each of the | |
1007 | * subsequent ASCONF Chunks. If found, proceed to rule D4. | |
1008 | */ | |
1009 | static struct sctp_association *__sctp_rcv_asconf_lookup( | |
1010 | sctp_chunkhdr_t *ch, | |
1011 | const union sctp_addr *laddr, | |
bc92dd19 | 1012 | __be16 peer_port, |
df218577 VY |
1013 | struct sctp_transport **transportp) |
1014 | { | |
1015 | sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch; | |
1016 | struct sctp_af *af; | |
1017 | union sctp_addr_param *param; | |
1018 | union sctp_addr paddr; | |
1019 | ||
1020 | /* Skip over the ADDIP header and find the Address parameter */ | |
1021 | param = (union sctp_addr_param *)(asconf + 1); | |
1022 | ||
1023 | af = sctp_get_af_specific(param_type2af(param->v4.param_hdr.type)); | |
1024 | if (unlikely(!af)) | |
1025 | return NULL; | |
1026 | ||
1027 | af->from_addr_param(&paddr, param, peer_port, 0); | |
1028 | ||
1029 | return __sctp_lookup_association(laddr, &paddr, transportp); | |
1030 | } | |
1031 | ||
1032 | ||
bbd0d598 VY |
1033 | /* SCTP-AUTH, Section 6.3: |
1034 | * If the receiver does not find a STCB for a packet containing an AUTH | |
1035 | * chunk as the first chunk and not a COOKIE-ECHO chunk as the second | |
1036 | * chunk, it MUST use the chunks after the AUTH chunk to look up an existing | |
1037 | * association. | |
1038 | * | |
1039 | * This means that any chunks that can help us identify the association need | |
1040 | * to be looked at to find this assocation. | |
bbd0d598 | 1041 | */ |
df218577 | 1042 | static struct sctp_association *__sctp_rcv_walk_lookup(struct sk_buff *skb, |
bbd0d598 VY |
1043 | const union sctp_addr *laddr, |
1044 | struct sctp_transport **transportp) | |
1045 | { | |
df218577 VY |
1046 | struct sctp_association *asoc = NULL; |
1047 | sctp_chunkhdr_t *ch; | |
1048 | int have_auth = 0; | |
1049 | unsigned int chunk_num = 1; | |
1050 | __u8 *ch_end; | |
1051 | ||
1052 | /* Walk through the chunks looking for AUTH or ASCONF chunks | |
1053 | * to help us find the association. | |
bbd0d598 | 1054 | */ |
df218577 VY |
1055 | ch = (sctp_chunkhdr_t *) skb->data; |
1056 | do { | |
1057 | /* Break out if chunk length is less then minimal. */ | |
1058 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
1059 | break; | |
1060 | ||
1061 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
1062 | if (ch_end > skb_tail_pointer(skb)) | |
1063 | break; | |
1064 | ||
1065 | switch(ch->type) { | |
1066 | case SCTP_CID_AUTH: | |
1067 | have_auth = chunk_num; | |
1068 | break; | |
1069 | ||
1070 | case SCTP_CID_COOKIE_ECHO: | |
1071 | /* If a packet arrives containing an AUTH chunk as | |
1072 | * a first chunk, a COOKIE-ECHO chunk as the second | |
1073 | * chunk, and possibly more chunks after them, and | |
1074 | * the receiver does not have an STCB for that | |
1075 | * packet, then authentication is based on | |
1076 | * the contents of the COOKIE- ECHO chunk. | |
1077 | */ | |
1078 | if (have_auth == 1 && chunk_num == 2) | |
1079 | return NULL; | |
1080 | break; | |
1081 | ||
1082 | case SCTP_CID_ASCONF: | |
1083 | if (have_auth || sctp_addip_noauth) | |
1084 | asoc = __sctp_rcv_asconf_lookup(ch, laddr, | |
1085 | sctp_hdr(skb)->source, | |
1086 | transportp); | |
1087 | default: | |
1088 | break; | |
1089 | } | |
1090 | ||
1091 | if (asoc) | |
1092 | break; | |
1093 | ||
1094 | ch = (sctp_chunkhdr_t *) ch_end; | |
1095 | chunk_num++; | |
1096 | } while (ch_end < skb_tail_pointer(skb)); | |
1097 | ||
1098 | return asoc; | |
bbd0d598 VY |
1099 | } |
1100 | ||
1101 | /* | |
1102 | * There are circumstances when we need to look inside the SCTP packet | |
1103 | * for information to help us find the association. Examples | |
1104 | * include looking inside of INIT/INIT-ACK chunks or after the AUTH | |
1105 | * chunks. | |
1106 | */ | |
1107 | static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb, | |
bbd0d598 VY |
1108 | const union sctp_addr *laddr, |
1109 | struct sctp_transport **transportp) | |
1110 | { | |
1111 | sctp_chunkhdr_t *ch; | |
1112 | ||
1113 | ch = (sctp_chunkhdr_t *) skb->data; | |
1114 | ||
df218577 VY |
1115 | /* The code below will attempt to walk the chunk and extract |
1116 | * parameter information. Before we do that, we need to verify | |
1117 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
1118 | * walk off the end. | |
1119 | */ | |
1120 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
1121 | return NULL; | |
1122 | ||
bbd0d598 VY |
1123 | /* If this is INIT/INIT-ACK look inside the chunk too. */ |
1124 | switch (ch->type) { | |
1125 | case SCTP_CID_INIT: | |
1126 | case SCTP_CID_INIT_ACK: | |
1127 | return __sctp_rcv_init_lookup(skb, laddr, transportp); | |
1128 | break; | |
1129 | ||
df218577 VY |
1130 | default: |
1131 | return __sctp_rcv_walk_lookup(skb, laddr, transportp); | |
bbd0d598 VY |
1132 | break; |
1133 | } | |
1134 | ||
df218577 | 1135 | |
bbd0d598 VY |
1136 | return NULL; |
1137 | } | |
1138 | ||
1da177e4 LT |
1139 | /* Lookup an association for an inbound skb. */ |
1140 | static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, | |
1141 | const union sctp_addr *paddr, | |
1142 | const union sctp_addr *laddr, | |
1143 | struct sctp_transport **transportp) | |
1144 | { | |
1145 | struct sctp_association *asoc; | |
1146 | ||
1147 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
1148 | ||
1149 | /* Further lookup for INIT/INIT-ACK packets. | |
1150 | * SCTP Implementors Guide, 2.18 Handling of address | |
1151 | * parameters within the INIT or INIT-ACK. | |
1152 | */ | |
1153 | if (!asoc) | |
df218577 | 1154 | asoc = __sctp_rcv_lookup_harder(skb, laddr, transportp); |
1da177e4 LT |
1155 | |
1156 | return asoc; | |
1157 | } |