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 */ | |
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> | |
9ad0977f | 63 | #include <net/sctp/checksum.h> |
dcfc23ca | 64 | #include <net/net_namespace.h> |
1da177e4 LT |
65 | |
66 | /* Forward declarations for internal helpers. */ | |
67 | static int sctp_rcv_ootb(struct sk_buff *); | |
68 | static 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); | |
72 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr); | |
73 | static struct sctp_association *__sctp_lookup_association( | |
74 | const union sctp_addr *local, | |
75 | const union sctp_addr *peer, | |
76 | struct sctp_transport **pt); | |
77 | ||
61c9fed4 VY |
78 | static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb); |
79 | ||
1da177e4 LT |
80 | |
81 | /* Calculate the SCTP checksum of an SCTP packet. */ | |
82 | static inline int sctp_rcv_checksum(struct sk_buff *skb) | |
83 | { | |
1da177e4 | 84 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
2c0fd387 | 85 | struct sctphdr *sh = sctp_hdr(skb); |
336d3262 HH |
86 | __be32 cmp = sh->checksum; |
87 | __be32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); | |
1da177e4 LT |
88 | |
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 | ||
79af02c2 DM |
103 | struct 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 | ||
1da177e4 LT |
114 | /* |
115 | * This is the routine which IP calls when receiving an SCTP packet. | |
116 | */ | |
117 | int 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; | |
1da177e4 LT |
130 | |
131 | if (skb->pkt_type!=PACKET_HOST) | |
132 | goto discard_it; | |
133 | ||
134 | SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS); | |
135 | ||
28cd7752 HX |
136 | if (skb_linearize(skb)) |
137 | goto discard_it; | |
138 | ||
2c0fd387 | 139 | sh = sctp_hdr(skb); |
1da177e4 LT |
140 | |
141 | /* Pull up the IP and SCTP headers. */ | |
ea2ae17d | 142 | __skb_pull(skb, skb_transport_offset(skb)); |
1da177e4 LT |
143 | if (skb->len < sizeof(struct sctphdr)) |
144 | goto discard_it; | |
60476372 | 145 | if (!skb_csum_unnecessary(skb) && sctp_rcv_checksum(skb) < 0) |
1da177e4 LT |
146 | 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 | ||
eddc9ec5 | 154 | family = ipver2af(ip_hdr(skb)->version); |
1da177e4 LT |
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 | */ | |
5636bef7 VY |
174 | if (!af->addr_valid(&src, NULL, skb) || |
175 | !af->addr_valid(&dest, NULL, skb)) | |
1da177e4 LT |
176 | goto discard_it; |
177 | ||
d55c41b1 | 178 | asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport); |
1c7d1fc1 | 179 | |
0fd9a65a | 180 | if (!asoc) |
d55c41b1 | 181 | ep = __sctp_rcv_lookup_endpoint(&dest); |
0fd9a65a NH |
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 | { | |
0fd9a65a NH |
193 | 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); | |
0fd9a65a NH |
203 | rcvr = &ep->base; |
204 | } | |
205 | ||
1da177e4 LT |
206 | /* |
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) { | |
1da177e4 LT |
215 | if (sctp_rcv_ootb(skb)) { |
216 | SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES); | |
217 | goto discard_release; | |
218 | } | |
219 | } | |
220 | ||
1da177e4 LT |
221 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
222 | goto discard_release; | |
b59c2701 | 223 | nf_reset(skb); |
1da177e4 | 224 | |
fda9ef5d | 225 | if (sk_filter(sk, skb)) |
d808ad9a | 226 | goto discard_release; |
1da177e4 LT |
227 | |
228 | /* Create an SCTP packet structure. */ | |
229 | chunk = sctp_chunkify(skb, asoc, sk); | |
2babf9da | 230 | if (!chunk) |
1da177e4 | 231 | goto discard_release; |
79af02c2 | 232 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 233 | |
1da177e4 LT |
234 | /* 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. */ | |
d55c41b1 | 241 | sctp_init_addrs(chunk, &src, &dest); |
1da177e4 LT |
242 | |
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 | ||
ac0b0462 SS |
252 | if (sock_owned_by_user(sk)) { |
253 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG); | |
61c9fed4 | 254 | sctp_add_backlog(sk, skb); |
ac0b0462 SS |
255 | } else { |
256 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ); | |
61c9fed4 | 257 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 258 | } |
1da177e4 | 259 | |
1da177e4 | 260 | sctp_bh_unlock_sock(sk); |
61c9fed4 VY |
261 | |
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); | |
7a48f923 | 267 | |
2babf9da | 268 | return 0; |
1da177e4 LT |
269 | |
270 | discard_it: | |
ac0b0462 | 271 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS); |
1da177e4 | 272 | kfree_skb(skb); |
2babf9da | 273 | return 0; |
1da177e4 LT |
274 | |
275 | discard_release: | |
61c9fed4 | 276 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 277 | if (asoc) |
1da177e4 | 278 | sctp_association_put(asoc); |
0fd9a65a | 279 | else |
1da177e4 | 280 | sctp_endpoint_put(ep); |
1da177e4 LT |
281 | |
282 | goto discard_it; | |
283 | } | |
284 | ||
61c9fed4 VY |
285 | /* 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. | |
1da177e4 LT |
289 | */ |
290 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
291 | { | |
79af02c2 | 292 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
d808ad9a YH |
293 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
294 | struct sctp_ep_common *rcvr = NULL; | |
61c9fed4 | 295 | int backloged = 0; |
7a48f923 | 296 | |
d808ad9a | 297 | rcvr = chunk->rcvr; |
c4d2444e | 298 | |
61c9fed4 VY |
299 | /* 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 | } | |
307 | ||
308 | 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 | */ | |
319 | ||
320 | 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 | ||
338 | done: | |
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 | ||
d808ad9a | 347 | return 0; |
1da177e4 LT |
348 | } |
349 | ||
61c9fed4 | 350 | static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 351 | { |
61c9fed4 VY |
352 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
353 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
c4d2444e | 354 | |
61c9fed4 VY |
355 | /* 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(); | |
364 | ||
365 | sk_add_backlog(sk, skb); | |
c4d2444e SS |
366 | } |
367 | ||
1da177e4 LT |
368 | /* Handle icmp frag needed error. */ |
369 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
370 | struct sctp_transport *t, __u32 pmtu) | |
371 | { | |
8a479491 | 372 | if (!t || (t->pathmtu == pmtu)) |
52ccb8e9 FF |
373 | return; |
374 | ||
8a479491 VY |
375 | if (sock_owned_by_user(sk)) { |
376 | asoc->pmtu_pending = 1; | |
377 | t->pmtu_pending = 1; | |
378 | return; | |
379 | } | |
380 | ||
52ccb8e9 | 381 | if (t->param_flags & SPP_PMTUD_ENABLE) { |
c910b47e VY |
382 | /* Update transports view of the MTU */ |
383 | sctp_transport_update_pmtu(t, pmtu); | |
1da177e4 | 384 | |
52ccb8e9 | 385 | /* Update association pmtu. */ |
1da177e4 | 386 | sctp_assoc_sync_pmtu(asoc); |
1da177e4 | 387 | } |
52ccb8e9 FF |
388 | |
389 | /* 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 | |
d808ad9a | 393 | * would not be fragmented, so it must be re-transmitted fragmented. |
52ccb8e9 FF |
394 | */ |
395 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
396 | } |
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 | */ | |
409 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
d808ad9a YH |
410 | struct sctp_association *asoc, |
411 | struct sctp_transport *t) | |
1da177e4 | 412 | { |
0dc47877 | 413 | SCTP_DEBUG_PRINTK("%s\n", __func__); |
1da177e4 LT |
414 | |
415 | sctp_do_sm(SCTP_EVENT_T_OTHER, | |
416 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), | |
3f7a87d2 | 417 | asoc->state, asoc->ep, asoc, t, |
1da177e4 LT |
418 | GFP_ATOMIC); |
419 | ||
420 | } | |
421 | ||
422 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
423 | struct sock *sctp_err_lookup(int family, struct sk_buff *skb, | |
424 | struct sctphdr *sctphdr, | |
1da177e4 LT |
425 | 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; | |
8de8c873 | 432 | struct sctp_association *asoc; |
1da177e4 | 433 | struct sctp_transport *transport = NULL; |
7115e632 WY |
434 | struct sctp_init_chunk *chunkhdr; |
435 | __u32 vtag = ntohl(sctphdr->vtag); | |
436 | int len = skb->len - ((void *)sctphdr - (void *)skb->data); | |
1da177e4 | 437 | |
d1ad1ff2 | 438 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
439 | |
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 | */ | |
d55c41b1 | 452 | asoc = __sctp_lookup_association(&saddr, &daddr, &transport); |
d1ad1ff2 SS |
453 | if (!asoc) |
454 | return NULL; | |
1da177e4 | 455 | |
d1ad1ff2 | 456 | sk = asoc->base.sk; |
1da177e4 | 457 | |
7115e632 WY |
458 | /* 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) { | |
d1ad1ff2 SS |
480 | goto out; |
481 | } | |
1da177e4 LT |
482 | |
483 | 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)) | |
de0744af | 489 | NET_INC_STATS_BH(&init_net, LINUX_MIB_LOCKDROPPEDICMPS); |
1da177e4 | 490 | |
1da177e4 LT |
491 | *app = asoc; |
492 | *tpp = transport; | |
493 | return sk; | |
494 | ||
495 | out: | |
1da177e4 LT |
496 | if (asoc) |
497 | sctp_association_put(asoc); | |
1da177e4 LT |
498 | return NULL; |
499 | } | |
500 | ||
501 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 502 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
503 | { |
504 | sctp_bh_unlock_sock(sk); | |
1da177e4 LT |
505 | if (asoc) |
506 | sctp_association_put(asoc); | |
1da177e4 LT |
507 | } |
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 | */ | |
524 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
525 | { | |
526 | struct iphdr *iph = (struct iphdr *)skb->data; | |
a27ef749 | 527 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
528 | const int type = icmp_hdr(skb)->type; |
529 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 530 | struct sock *sk; |
8de8c873 | 531 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
532 | struct sctp_transport *transport; |
533 | struct inet_sock *inet; | |
2e07fa9c | 534 | sk_buff_data_t saveip, savesctp; |
1da177e4 LT |
535 | int err; |
536 | ||
a27ef749 | 537 | if (skb->len < ihlen + 8) { |
dcfc23ca | 538 | ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS); |
1da177e4 LT |
539 | return; |
540 | } | |
541 | ||
542 | /* Fix up skb to look at the embedded net header. */ | |
b0e380b1 ACM |
543 | saveip = skb->network_header; |
544 | savesctp = skb->transport_header; | |
31c7711b | 545 | skb_reset_network_header(skb); |
a27ef749 ACM |
546 | skb_set_transport_header(skb, ihlen); |
547 | sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport); | |
2e07fa9c | 548 | /* Put back, the original values. */ |
b0e380b1 ACM |
549 | skb->network_header = saveip; |
550 | skb->transport_header = savesctp; | |
1da177e4 | 551 | if (!sk) { |
dcfc23ca | 552 | ICMP_INC_STATS_BH(&init_net, ICMP_MIB_INERRORS); |
1da177e4 LT |
553 | 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) { | |
d1ad1ff2 | 574 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
575 | 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 | ||
602 | out_unlock: | |
d1ad1ff2 | 603 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
604 | } |
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 | */ | |
04675210 | 618 | static int sctp_rcv_ootb(struct sk_buff *skb) |
1da177e4 LT |
619 | { |
620 | sctp_chunkhdr_t *ch; | |
621 | __u8 *ch_end; | |
622 | sctp_errhdr_t *err; | |
623 | ||
624 | ch = (sctp_chunkhdr_t *) skb->data; | |
1da177e4 LT |
625 | |
626 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 TF |
627 | 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)); | |
27a884dc | 633 | if (ch_end > skb_tail_pointer(skb)) |
a7d1f1b6 | 634 | break; |
1da177e4 LT |
635 | |
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 | ||
3c77f961 VY |
650 | /* 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 | ||
1da177e4 LT |
658 | /* 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; | |
27a884dc | 673 | } while (ch_end < skb_tail_pointer(skb)); |
1da177e4 LT |
674 | |
675 | return 0; | |
676 | ||
677 | discard: | |
678 | return 1; | |
679 | } | |
680 | ||
681 | /* Insert endpoint into the hash table. */ | |
682 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
683 | { | |
1da177e4 LT |
684 | 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); | |
d970dbf8 | 693 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
694 | sctp_write_unlock(&head->lock); |
695 | } | |
696 | ||
697 | /* Add an endpoint to the hash. Local BH-safe. */ | |
698 | void 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. */ | |
706 | static 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 | ||
d970dbf8 VY |
713 | if (hlist_unhashed(&epb->node)) |
714 | return; | |
715 | ||
1da177e4 LT |
716 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); |
717 | ||
718 | head = &sctp_ep_hashtable[epb->hashent]; | |
719 | ||
720 | sctp_write_lock(&head->lock); | |
d970dbf8 | 721 | __hlist_del(&epb->node); |
1da177e4 LT |
722 | sctp_write_unlock(&head->lock); |
723 | } | |
724 | ||
725 | /* Remove endpoint from the hash. Local BH-safe. */ | |
726 | void 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. */ | |
734 | static 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; | |
d970dbf8 | 739 | struct hlist_node *node; |
1da177e4 LT |
740 | int hash; |
741 | ||
1c7d1fc1 | 742 | hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
743 | head = &sctp_ep_hashtable[hash]; |
744 | read_lock(&head->lock); | |
d970dbf8 | 745 | sctp_for_each_hentry(epb, node, &head->chain) { |
1da177e4 LT |
746 | 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; | |
1da177e4 LT |
752 | |
753 | hit: | |
754 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
755 | read_unlock(&head->lock); |
756 | return ep; | |
757 | } | |
758 | ||
759 | /* Insert association into the hash table. */ | |
760 | static void __sctp_hash_established(struct sctp_association *asoc) | |
761 | { | |
1da177e4 LT |
762 | 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); | |
d970dbf8 | 773 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
774 | sctp_write_unlock(&head->lock); |
775 | } | |
776 | ||
777 | /* Add an association to the hash. Local BH-safe. */ | |
778 | void sctp_hash_established(struct sctp_association *asoc) | |
779 | { | |
de76e695 VY |
780 | if (asoc->temp) |
781 | return; | |
782 | ||
1da177e4 LT |
783 | sctp_local_bh_disable(); |
784 | __sctp_hash_established(asoc); | |
785 | sctp_local_bh_enable(); | |
786 | } | |
787 | ||
788 | /* Remove association from the hash table. */ | |
789 | static 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); | |
d970dbf8 | 802 | __hlist_del(&epb->node); |
1da177e4 LT |
803 | sctp_write_unlock(&head->lock); |
804 | } | |
805 | ||
806 | /* Remove association from the hash table. Local BH-safe. */ | |
807 | void sctp_unhash_established(struct sctp_association *asoc) | |
808 | { | |
de76e695 VY |
809 | if (asoc->temp) |
810 | return; | |
811 | ||
1da177e4 LT |
812 | sctp_local_bh_disable(); |
813 | __sctp_unhash_established(asoc); | |
814 | sctp_local_bh_enable(); | |
815 | } | |
816 | ||
817 | /* Look up an association. */ | |
818 | static 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; | |
d970dbf8 | 827 | struct hlist_node *node; |
1da177e4 LT |
828 | int hash; |
829 | ||
830 | /* Optimize here for direct hit, only listening connections can | |
831 | * have wildcards anyways. | |
832 | */ | |
e2fccedb | 833 | hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port)); |
1da177e4 LT |
834 | head = &sctp_assoc_hashtable[hash]; |
835 | read_lock(&head->lock); | |
d970dbf8 | 836 | sctp_for_each_hentry(epb, node, &head->chain) { |
1da177e4 LT |
837 | 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 | ||
847 | hit: | |
848 | *pt = transport; | |
849 | sctp_association_hold(asoc); | |
1da177e4 LT |
850 | read_unlock(&head->lock); |
851 | return asoc; | |
852 | } | |
853 | ||
854 | /* Look up an association. BH-safe. */ | |
855 | SCTP_STATIC | |
856 | struct 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? */ | |
870 | int 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 | ||
6c7be55c | 876 | if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) { |
1da177e4 LT |
877 | 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 | */ | |
902 | static 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; | |
2c0fd387 | 908 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
909 | 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 | ||
1da177e4 LT |
917 | /* |
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 | ||
dd86d136 | 943 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 944 | |
dd86d136 | 945 | asoc = __sctp_lookup_association(laddr, paddr, &transport); |
1da177e4 LT |
946 | if (asoc) |
947 | return asoc; | |
948 | } | |
949 | ||
950 | return NULL; | |
951 | } | |
952 | ||
df218577 VY |
953 | /* 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 | */ | |
967 | static struct sctp_association *__sctp_rcv_asconf_lookup( | |
968 | sctp_chunkhdr_t *ch, | |
969 | const union sctp_addr *laddr, | |
bc92dd19 | 970 | __be16 peer_port, |
df218577 VY |
971 | 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 | ||
bbd0d598 VY |
991 | /* 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. | |
bbd0d598 | 999 | */ |
df218577 | 1000 | static struct sctp_association *__sctp_rcv_walk_lookup(struct sk_buff *skb, |
bbd0d598 VY |
1001 | const union sctp_addr *laddr, |
1002 | struct sctp_transport **transportp) | |
1003 | { | |
df218577 VY |
1004 | 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. | |
bbd0d598 | 1012 | */ |
df218577 VY |
1013 | 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; | |
bbd0d598 VY |
1057 | } |
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 | */ | |
1065 | static struct sctp_association *__sctp_rcv_lookup_harder(struct sk_buff *skb, | |
bbd0d598 VY |
1066 | 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 | ||
df218577 VY |
1073 | /* 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 | ||
bbd0d598 VY |
1081 | /* 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 | ||
df218577 VY |
1088 | default: |
1089 | return __sctp_rcv_walk_lookup(skb, laddr, transportp); | |
bbd0d598 VY |
1090 | break; |
1091 | } | |
1092 | ||
df218577 | 1093 | |
bbd0d598 VY |
1094 | return NULL; |
1095 | } | |
1096 | ||
1da177e4 LT |
1097 | /* Lookup an association for an inbound skb. */ |
1098 | static 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) | |
df218577 | 1112 | asoc = __sctp_rcv_lookup_harder(skb, laddr, transportp); |
1da177e4 LT |
1113 | |
1114 | return asoc; | |
1115 | } |