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 *); | |
4110cc25 EB |
69 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
70 | struct sk_buff *skb, | |
1da177e4 | 71 | const union sctp_addr *paddr, |
57565993 | 72 | const union sctp_addr *laddr, |
1da177e4 | 73 | struct sctp_transport **transportp); |
4cdadcbc EB |
74 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net, |
75 | const union sctp_addr *laddr); | |
1da177e4 | 76 | static struct sctp_association *__sctp_lookup_association( |
4110cc25 | 77 | struct net *net, |
1da177e4 LT |
78 | const union sctp_addr *local, |
79 | const union sctp_addr *peer, | |
80 | struct sctp_transport **pt); | |
81 | ||
50b1a782 | 82 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb); |
61c9fed4 | 83 | |
1da177e4 LT |
84 | |
85 | /* Calculate the SCTP checksum of an SCTP packet. */ | |
b01a2407 | 86 | static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb) |
1da177e4 | 87 | { |
2c0fd387 | 88 | struct sctphdr *sh = sctp_hdr(skb); |
4458f04c | 89 | __le32 cmp = sh->checksum; |
1b003be3 | 90 | struct sk_buff *list; |
4458f04c VY |
91 | __le32 val; |
92 | __u32 tmp = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); | |
1da177e4 | 93 | |
1b003be3 | 94 | skb_walk_frags(skb, list) |
4458f04c VY |
95 | tmp = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), |
96 | tmp); | |
1da177e4 | 97 | |
4458f04c | 98 | val = sctp_end_cksum(tmp); |
1da177e4 LT |
99 | |
100 | if (val != cmp) { | |
101 | /* CRC failure, dump it. */ | |
b01a2407 | 102 | SCTP_INC_STATS_BH(net, SCTP_MIB_CHECKSUMERRORS); |
1da177e4 LT |
103 | return -1; |
104 | } | |
105 | return 0; | |
106 | } | |
107 | ||
79af02c2 DM |
108 | struct sctp_input_cb { |
109 | union { | |
110 | struct inet_skb_parm h4; | |
dfd56b8b | 111 | #if IS_ENABLED(CONFIG_IPV6) |
79af02c2 DM |
112 | struct inet6_skb_parm h6; |
113 | #endif | |
114 | } header; | |
115 | struct sctp_chunk *chunk; | |
116 | }; | |
117 | #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) | |
118 | ||
1da177e4 LT |
119 | /* |
120 | * This is the routine which IP calls when receiving an SCTP packet. | |
121 | */ | |
122 | int sctp_rcv(struct sk_buff *skb) | |
123 | { | |
124 | struct sock *sk; | |
125 | struct sctp_association *asoc; | |
126 | struct sctp_endpoint *ep = NULL; | |
127 | struct sctp_ep_common *rcvr; | |
128 | struct sctp_transport *transport = NULL; | |
129 | struct sctp_chunk *chunk; | |
130 | struct sctphdr *sh; | |
131 | union sctp_addr src; | |
132 | union sctp_addr dest; | |
133 | int family; | |
134 | struct sctp_af *af; | |
4cdadcbc | 135 | struct net *net = dev_net(skb->dev); |
1da177e4 LT |
136 | |
137 | if (skb->pkt_type!=PACKET_HOST) | |
138 | goto discard_it; | |
139 | ||
b01a2407 | 140 | SCTP_INC_STATS_BH(net, SCTP_MIB_INSCTPPACKS); |
1da177e4 | 141 | |
28cd7752 HX |
142 | if (skb_linearize(skb)) |
143 | goto discard_it; | |
144 | ||
2c0fd387 | 145 | sh = sctp_hdr(skb); |
1da177e4 LT |
146 | |
147 | /* Pull up the IP and SCTP headers. */ | |
ea2ae17d | 148 | __skb_pull(skb, skb_transport_offset(skb)); |
1da177e4 LT |
149 | if (skb->len < sizeof(struct sctphdr)) |
150 | goto discard_it; | |
06e86806 | 151 | if (!sctp_checksum_disable && !skb_csum_unnecessary(skb) && |
b01a2407 | 152 | sctp_rcv_checksum(net, skb) < 0) |
1da177e4 LT |
153 | goto discard_it; |
154 | ||
155 | skb_pull(skb, sizeof(struct sctphdr)); | |
156 | ||
157 | /* Make sure we at least have chunk headers worth of data left. */ | |
158 | if (skb->len < sizeof(struct sctp_chunkhdr)) | |
159 | goto discard_it; | |
160 | ||
eddc9ec5 | 161 | family = ipver2af(ip_hdr(skb)->version); |
1da177e4 LT |
162 | af = sctp_get_af_specific(family); |
163 | if (unlikely(!af)) | |
164 | goto discard_it; | |
165 | ||
166 | /* Initialize local addresses for lookups. */ | |
167 | af->from_skb(&src, skb, 1); | |
168 | af->from_skb(&dest, skb, 0); | |
169 | ||
170 | /* If the packet is to or from a non-unicast address, | |
171 | * silently discard the packet. | |
172 | * | |
173 | * This is not clearly defined in the RFC except in section | |
174 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
175 | * Transmission Protocol" 2.1, "It is important to note that the | |
176 | * IP address of an SCTP transport address must be a routable | |
177 | * unicast address. In other words, IP multicast addresses and | |
178 | * IP broadcast addresses cannot be used in an SCTP transport | |
179 | * address." | |
180 | */ | |
5636bef7 VY |
181 | if (!af->addr_valid(&src, NULL, skb) || |
182 | !af->addr_valid(&dest, NULL, skb)) | |
1da177e4 LT |
183 | goto discard_it; |
184 | ||
4110cc25 | 185 | asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport); |
1c7d1fc1 | 186 | |
0fd9a65a | 187 | if (!asoc) |
4cdadcbc | 188 | ep = __sctp_rcv_lookup_endpoint(net, &dest); |
0fd9a65a NH |
189 | |
190 | /* Retrieve the common input handling substructure. */ | |
191 | rcvr = asoc ? &asoc->base : &ep->base; | |
192 | sk = rcvr->sk; | |
193 | ||
194 | /* | |
195 | * If a frame arrives on an interface and the receiving socket is | |
196 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
197 | */ | |
198 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) | |
199 | { | |
0fd9a65a NH |
200 | if (asoc) { |
201 | sctp_association_put(asoc); | |
202 | asoc = NULL; | |
203 | } else { | |
204 | sctp_endpoint_put(ep); | |
205 | ep = NULL; | |
206 | } | |
2ce95503 | 207 | sk = net->sctp.ctl_sock; |
0fd9a65a NH |
208 | ep = sctp_sk(sk)->ep; |
209 | sctp_endpoint_hold(ep); | |
0fd9a65a NH |
210 | rcvr = &ep->base; |
211 | } | |
212 | ||
1da177e4 LT |
213 | /* |
214 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
215 | * An SCTP packet is called an "out of the blue" (OOTB) | |
216 | * packet if it is correctly formed, i.e., passed the | |
217 | * receiver's checksum check, but the receiver is not | |
218 | * able to identify the association to which this | |
219 | * packet belongs. | |
220 | */ | |
221 | if (!asoc) { | |
1da177e4 | 222 | if (sctp_rcv_ootb(skb)) { |
b01a2407 | 223 | SCTP_INC_STATS_BH(net, SCTP_MIB_OUTOFBLUES); |
1da177e4 LT |
224 | goto discard_release; |
225 | } | |
226 | } | |
227 | ||
1da177e4 LT |
228 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
229 | goto discard_release; | |
b59c2701 | 230 | nf_reset(skb); |
1da177e4 | 231 | |
fda9ef5d | 232 | if (sk_filter(sk, skb)) |
d808ad9a | 233 | goto discard_release; |
1da177e4 LT |
234 | |
235 | /* Create an SCTP packet structure. */ | |
236 | chunk = sctp_chunkify(skb, asoc, sk); | |
2babf9da | 237 | if (!chunk) |
1da177e4 | 238 | goto discard_release; |
79af02c2 | 239 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 240 | |
1da177e4 LT |
241 | /* Remember what endpoint is to handle this packet. */ |
242 | chunk->rcvr = rcvr; | |
243 | ||
244 | /* Remember the SCTP header. */ | |
245 | chunk->sctp_hdr = sh; | |
246 | ||
247 | /* Set the source and destination addresses of the incoming chunk. */ | |
d55c41b1 | 248 | sctp_init_addrs(chunk, &src, &dest); |
1da177e4 LT |
249 | |
250 | /* Remember where we came from. */ | |
251 | chunk->transport = transport; | |
252 | ||
253 | /* Acquire access to the sock lock. Note: We are safe from other | |
254 | * bottom halves on this lock, but a user may be in the lock too, | |
255 | * so check if it is busy. | |
256 | */ | |
257 | sctp_bh_lock_sock(sk); | |
258 | ||
ae53b5bd VY |
259 | if (sk != rcvr->sk) { |
260 | /* Our cached sk is different from the rcvr->sk. This is | |
261 | * because migrate()/accept() may have moved the association | |
262 | * to a new socket and released all the sockets. So now we | |
263 | * are holding a lock on the old socket while the user may | |
264 | * be doing something with the new socket. Switch our veiw | |
265 | * of the current sk. | |
266 | */ | |
267 | sctp_bh_unlock_sock(sk); | |
268 | sk = rcvr->sk; | |
269 | sctp_bh_lock_sock(sk); | |
270 | } | |
271 | ||
ac0b0462 | 272 | if (sock_owned_by_user(sk)) { |
50b1a782 ZY |
273 | if (sctp_add_backlog(sk, skb)) { |
274 | sctp_bh_unlock_sock(sk); | |
275 | sctp_chunk_free(chunk); | |
276 | skb = NULL; /* sctp_chunk_free already freed the skb */ | |
277 | goto discard_release; | |
278 | } | |
b01a2407 | 279 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_BACKLOG); |
ac0b0462 | 280 | } else { |
b01a2407 | 281 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_SOFTIRQ); |
61c9fed4 | 282 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 283 | } |
1da177e4 | 284 | |
1da177e4 | 285 | sctp_bh_unlock_sock(sk); |
61c9fed4 VY |
286 | |
287 | /* Release the asoc/ep ref we took in the lookup calls. */ | |
288 | if (asoc) | |
289 | sctp_association_put(asoc); | |
290 | else | |
291 | sctp_endpoint_put(ep); | |
7a48f923 | 292 | |
2babf9da | 293 | return 0; |
1da177e4 LT |
294 | |
295 | discard_it: | |
b01a2407 | 296 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_DISCARDS); |
1da177e4 | 297 | kfree_skb(skb); |
2babf9da | 298 | return 0; |
1da177e4 LT |
299 | |
300 | discard_release: | |
61c9fed4 | 301 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 302 | if (asoc) |
1da177e4 | 303 | sctp_association_put(asoc); |
0fd9a65a | 304 | else |
1da177e4 | 305 | sctp_endpoint_put(ep); |
1da177e4 LT |
306 | |
307 | goto discard_it; | |
308 | } | |
309 | ||
61c9fed4 VY |
310 | /* Process the backlog queue of the socket. Every skb on |
311 | * the backlog holds a ref on an association or endpoint. | |
312 | * We hold this ref throughout the state machine to make | |
313 | * sure that the structure we need is still around. | |
1da177e4 LT |
314 | */ |
315 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
316 | { | |
79af02c2 | 317 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
d808ad9a YH |
318 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
319 | struct sctp_ep_common *rcvr = NULL; | |
61c9fed4 | 320 | int backloged = 0; |
7a48f923 | 321 | |
d808ad9a | 322 | rcvr = chunk->rcvr; |
c4d2444e | 323 | |
61c9fed4 VY |
324 | /* If the rcvr is dead then the association or endpoint |
325 | * has been deleted and we can safely drop the chunk | |
326 | * and refs that we are holding. | |
327 | */ | |
328 | if (rcvr->dead) { | |
329 | sctp_chunk_free(chunk); | |
330 | goto done; | |
331 | } | |
332 | ||
333 | if (unlikely(rcvr->sk != sk)) { | |
334 | /* In this case, the association moved from one socket to | |
335 | * another. We are currently sitting on the backlog of the | |
336 | * old socket, so we need to move. | |
337 | * However, since we are here in the process context we | |
338 | * need to take make sure that the user doesn't own | |
339 | * the new socket when we process the packet. | |
340 | * If the new socket is user-owned, queue the chunk to the | |
341 | * backlog of the new socket without dropping any refs. | |
342 | * Otherwise, we can safely push the chunk on the inqueue. | |
343 | */ | |
344 | ||
345 | sk = rcvr->sk; | |
346 | sctp_bh_lock_sock(sk); | |
347 | ||
348 | if (sock_owned_by_user(sk)) { | |
f545a38f | 349 | if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) |
50b1a782 ZY |
350 | sctp_chunk_free(chunk); |
351 | else | |
352 | backloged = 1; | |
61c9fed4 VY |
353 | } else |
354 | sctp_inq_push(inqueue, chunk); | |
355 | ||
356 | sctp_bh_unlock_sock(sk); | |
357 | ||
358 | /* If the chunk was backloged again, don't drop refs */ | |
359 | if (backloged) | |
360 | return 0; | |
361 | } else { | |
362 | sctp_inq_push(inqueue, chunk); | |
363 | } | |
364 | ||
365 | done: | |
366 | /* Release the refs we took in sctp_add_backlog */ | |
367 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
368 | sctp_association_put(sctp_assoc(rcvr)); | |
369 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
370 | sctp_endpoint_put(sctp_ep(rcvr)); | |
371 | else | |
372 | BUG(); | |
373 | ||
d808ad9a | 374 | return 0; |
1da177e4 LT |
375 | } |
376 | ||
50b1a782 | 377 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 378 | { |
61c9fed4 VY |
379 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
380 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
50b1a782 | 381 | int ret; |
c4d2444e | 382 | |
f545a38f | 383 | ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf); |
50b1a782 ZY |
384 | if (!ret) { |
385 | /* Hold the assoc/ep while hanging on the backlog queue. | |
386 | * This way, we know structures we need will not disappear | |
387 | * from us | |
388 | */ | |
389 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
390 | sctp_association_hold(sctp_assoc(rcvr)); | |
391 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
392 | sctp_endpoint_hold(sctp_ep(rcvr)); | |
393 | else | |
394 | BUG(); | |
395 | } | |
396 | return ret; | |
61c9fed4 | 397 | |
c4d2444e SS |
398 | } |
399 | ||
1da177e4 LT |
400 | /* Handle icmp frag needed error. */ |
401 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
402 | struct sctp_transport *t, __u32 pmtu) | |
403 | { | |
91bd6b1e | 404 | if (!t || (t->pathmtu <= pmtu)) |
52ccb8e9 FF |
405 | return; |
406 | ||
8a479491 VY |
407 | if (sock_owned_by_user(sk)) { |
408 | asoc->pmtu_pending = 1; | |
409 | t->pmtu_pending = 1; | |
410 | return; | |
411 | } | |
412 | ||
52ccb8e9 | 413 | if (t->param_flags & SPP_PMTUD_ENABLE) { |
c910b47e | 414 | /* Update transports view of the MTU */ |
02f3d4ce | 415 | sctp_transport_update_pmtu(sk, t, pmtu); |
1da177e4 | 416 | |
52ccb8e9 | 417 | /* Update association pmtu. */ |
02f3d4ce | 418 | sctp_assoc_sync_pmtu(sk, asoc); |
1da177e4 | 419 | } |
52ccb8e9 FF |
420 | |
421 | /* Retransmit with the new pmtu setting. | |
422 | * Normally, if PMTU discovery is disabled, an ICMP Fragmentation | |
423 | * Needed will never be sent, but if a message was sent before | |
424 | * PMTU discovery was disabled that was larger than the PMTU, it | |
d808ad9a | 425 | * would not be fragmented, so it must be re-transmitted fragmented. |
52ccb8e9 FF |
426 | */ |
427 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
428 | } |
429 | ||
ec18d9a2 DM |
430 | void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, |
431 | struct sk_buff *skb) | |
55be7a9c DM |
432 | { |
433 | struct dst_entry *dst; | |
434 | ||
435 | if (!t) | |
436 | return; | |
437 | dst = sctp_transport_dst_check(t); | |
1ed5c48f | 438 | if (dst) |
6700c270 | 439 | dst->ops->redirect(dst, sk, skb); |
55be7a9c DM |
440 | } |
441 | ||
1da177e4 LT |
442 | /* |
443 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
444 | * | |
445 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
446 | * or a "Protocol Unreachable" treat this message as an abort | |
447 | * with the T bit set. | |
448 | * | |
449 | * This function sends an event to the state machine, which will abort the | |
450 | * association. | |
451 | * | |
452 | */ | |
453 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
d808ad9a YH |
454 | struct sctp_association *asoc, |
455 | struct sctp_transport *t) | |
1da177e4 | 456 | { |
0dc47877 | 457 | SCTP_DEBUG_PRINTK("%s\n", __func__); |
1da177e4 | 458 | |
50b5d6ad VY |
459 | if (sock_owned_by_user(sk)) { |
460 | if (timer_pending(&t->proto_unreach_timer)) | |
461 | return; | |
462 | else { | |
463 | if (!mod_timer(&t->proto_unreach_timer, | |
464 | jiffies + (HZ/20))) | |
465 | sctp_association_hold(asoc); | |
466 | } | |
467 | ||
468 | } else { | |
55e26eb9 EB |
469 | struct net *net = sock_net(sk); |
470 | ||
25cc4ae9 | 471 | if (del_timer(&t->proto_unreach_timer)) |
50b5d6ad | 472 | sctp_association_put(asoc); |
1da177e4 | 473 | |
55e26eb9 | 474 | sctp_do_sm(net, SCTP_EVENT_T_OTHER, |
50b5d6ad VY |
475 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), |
476 | asoc->state, asoc->ep, asoc, t, | |
477 | GFP_ATOMIC); | |
478 | } | |
1da177e4 LT |
479 | } |
480 | ||
481 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
4110cc25 | 482 | struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb, |
1da177e4 | 483 | struct sctphdr *sctphdr, |
1da177e4 LT |
484 | struct sctp_association **app, |
485 | struct sctp_transport **tpp) | |
486 | { | |
487 | union sctp_addr saddr; | |
488 | union sctp_addr daddr; | |
489 | struct sctp_af *af; | |
490 | struct sock *sk = NULL; | |
8de8c873 | 491 | struct sctp_association *asoc; |
1da177e4 | 492 | struct sctp_transport *transport = NULL; |
7115e632 WY |
493 | struct sctp_init_chunk *chunkhdr; |
494 | __u32 vtag = ntohl(sctphdr->vtag); | |
495 | int len = skb->len - ((void *)sctphdr - (void *)skb->data); | |
1da177e4 | 496 | |
d1ad1ff2 | 497 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
498 | |
499 | af = sctp_get_af_specific(family); | |
500 | if (unlikely(!af)) { | |
501 | return NULL; | |
502 | } | |
503 | ||
504 | /* Initialize local addresses for lookups. */ | |
505 | af->from_skb(&saddr, skb, 1); | |
506 | af->from_skb(&daddr, skb, 0); | |
507 | ||
508 | /* Look for an association that matches the incoming ICMP error | |
509 | * packet. | |
510 | */ | |
4110cc25 | 511 | asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport); |
d1ad1ff2 SS |
512 | if (!asoc) |
513 | return NULL; | |
1da177e4 | 514 | |
d1ad1ff2 | 515 | sk = asoc->base.sk; |
1da177e4 | 516 | |
7115e632 WY |
517 | /* RFC 4960, Appendix C. ICMP Handling |
518 | * | |
519 | * ICMP6) An implementation MUST validate that the Verification Tag | |
520 | * contained in the ICMP message matches the Verification Tag of | |
521 | * the peer. If the Verification Tag is not 0 and does NOT | |
522 | * match, discard the ICMP message. If it is 0 and the ICMP | |
523 | * message contains enough bytes to verify that the chunk type is | |
524 | * an INIT chunk and that the Initiate Tag matches the tag of the | |
525 | * peer, continue with ICMP7. If the ICMP message is too short | |
526 | * or the chunk type or the Initiate Tag does not match, silently | |
527 | * discard the packet. | |
528 | */ | |
529 | if (vtag == 0) { | |
ea110733 | 530 | chunkhdr = (void *)sctphdr + sizeof(struct sctphdr); |
7115e632 WY |
531 | if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t) |
532 | + sizeof(__be32) || | |
533 | chunkhdr->chunk_hdr.type != SCTP_CID_INIT || | |
534 | ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) { | |
535 | goto out; | |
536 | } | |
537 | } else if (vtag != asoc->c.peer_vtag) { | |
d1ad1ff2 SS |
538 | goto out; |
539 | } | |
1da177e4 LT |
540 | |
541 | sctp_bh_lock_sock(sk); | |
542 | ||
543 | /* If too many ICMPs get dropped on busy | |
544 | * servers this needs to be solved differently. | |
545 | */ | |
546 | if (sock_owned_by_user(sk)) | |
b01a2407 | 547 | NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); |
1da177e4 | 548 | |
1da177e4 LT |
549 | *app = asoc; |
550 | *tpp = transport; | |
551 | return sk; | |
552 | ||
553 | out: | |
1da177e4 LT |
554 | if (asoc) |
555 | sctp_association_put(asoc); | |
1da177e4 LT |
556 | return NULL; |
557 | } | |
558 | ||
559 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 560 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
561 | { |
562 | sctp_bh_unlock_sock(sk); | |
1da177e4 LT |
563 | if (asoc) |
564 | sctp_association_put(asoc); | |
1da177e4 LT |
565 | } |
566 | ||
567 | /* | |
568 | * This routine is called by the ICMP module when it gets some | |
569 | * sort of error condition. If err < 0 then the socket should | |
570 | * be closed and the error returned to the user. If err > 0 | |
571 | * it's just the icmp type << 8 | icmp code. After adjustment | |
572 | * header points to the first 8 bytes of the sctp header. We need | |
573 | * to find the appropriate port. | |
574 | * | |
575 | * The locking strategy used here is very "optimistic". When | |
576 | * someone else accesses the socket the ICMP is just dropped | |
577 | * and for some paths there is no check at all. | |
578 | * A more general error queue to queue errors for later handling | |
579 | * is probably better. | |
580 | * | |
581 | */ | |
582 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
583 | { | |
b71d1d42 | 584 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
a27ef749 | 585 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
586 | const int type = icmp_hdr(skb)->type; |
587 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 588 | struct sock *sk; |
8de8c873 | 589 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
590 | struct sctp_transport *transport; |
591 | struct inet_sock *inet; | |
2e07fa9c | 592 | sk_buff_data_t saveip, savesctp; |
1da177e4 | 593 | int err; |
4110cc25 | 594 | struct net *net = dev_net(skb->dev); |
1da177e4 | 595 | |
a27ef749 | 596 | if (skb->len < ihlen + 8) { |
b01a2407 | 597 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
598 | return; |
599 | } | |
600 | ||
601 | /* Fix up skb to look at the embedded net header. */ | |
b0e380b1 ACM |
602 | saveip = skb->network_header; |
603 | savesctp = skb->transport_header; | |
31c7711b | 604 | skb_reset_network_header(skb); |
a27ef749 | 605 | skb_set_transport_header(skb, ihlen); |
4110cc25 | 606 | sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport); |
2e07fa9c | 607 | /* Put back, the original values. */ |
b0e380b1 ACM |
608 | skb->network_header = saveip; |
609 | skb->transport_header = savesctp; | |
1da177e4 | 610 | if (!sk) { |
b01a2407 | 611 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
612 | return; |
613 | } | |
614 | /* Warning: The sock lock is held. Remember to call | |
615 | * sctp_err_finish! | |
616 | */ | |
617 | ||
618 | switch (type) { | |
619 | case ICMP_PARAMETERPROB: | |
620 | err = EPROTO; | |
621 | break; | |
622 | case ICMP_DEST_UNREACH: | |
623 | if (code > NR_ICMP_UNREACH) | |
624 | goto out_unlock; | |
625 | ||
626 | /* PMTU discovery (RFC1191) */ | |
627 | if (ICMP_FRAG_NEEDED == code) { | |
628 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
629 | goto out_unlock; | |
630 | } | |
631 | else { | |
632 | if (ICMP_PROT_UNREACH == code) { | |
d1ad1ff2 | 633 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
634 | transport); |
635 | goto out_unlock; | |
636 | } | |
637 | } | |
638 | err = icmp_err_convert[code].errno; | |
639 | break; | |
640 | case ICMP_TIME_EXCEEDED: | |
641 | /* Ignore any time exceeded errors due to fragment reassembly | |
642 | * timeouts. | |
643 | */ | |
644 | if (ICMP_EXC_FRAGTIME == code) | |
645 | goto out_unlock; | |
646 | ||
647 | err = EHOSTUNREACH; | |
648 | break; | |
55be7a9c DM |
649 | case ICMP_REDIRECT: |
650 | sctp_icmp_redirect(sk, transport, skb); | |
651 | err = 0; | |
652 | break; | |
1da177e4 LT |
653 | default: |
654 | goto out_unlock; | |
655 | } | |
656 | ||
657 | inet = inet_sk(sk); | |
658 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
659 | sk->sk_err = err; | |
660 | sk->sk_error_report(sk); | |
661 | } else { /* Only an error on timeout */ | |
662 | sk->sk_err_soft = err; | |
663 | } | |
664 | ||
665 | out_unlock: | |
d1ad1ff2 | 666 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
667 | } |
668 | ||
669 | /* | |
670 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
671 | * | |
672 | * This function scans all the chunks in the OOTB packet to determine if | |
673 | * the packet should be discarded right away. If a response might be needed | |
674 | * for this packet, or, if further processing is possible, the packet will | |
675 | * be queued to a proper inqueue for the next phase of handling. | |
676 | * | |
677 | * Output: | |
678 | * Return 0 - If further processing is needed. | |
679 | * Return 1 - If the packet can be discarded right away. | |
680 | */ | |
04675210 | 681 | static int sctp_rcv_ootb(struct sk_buff *skb) |
1da177e4 LT |
682 | { |
683 | sctp_chunkhdr_t *ch; | |
684 | __u8 *ch_end; | |
1da177e4 LT |
685 | |
686 | ch = (sctp_chunkhdr_t *) skb->data; | |
1da177e4 LT |
687 | |
688 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 TF |
689 | do { |
690 | /* Break out if chunk length is less then minimal. */ | |
691 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
692 | break; | |
693 | ||
694 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
27a884dc | 695 | if (ch_end > skb_tail_pointer(skb)) |
a7d1f1b6 | 696 | break; |
1da177e4 LT |
697 | |
698 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
699 | * receiver MUST silently discard the OOTB packet and take no | |
700 | * further action. | |
701 | */ | |
702 | if (SCTP_CID_ABORT == ch->type) | |
703 | goto discard; | |
704 | ||
705 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
706 | * chunk, the receiver should silently discard the packet | |
707 | * and take no further action. | |
708 | */ | |
709 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
710 | goto discard; | |
711 | ||
3c77f961 VY |
712 | /* RFC 4460, 2.11.2 |
713 | * This will discard packets with INIT chunk bundled as | |
714 | * subsequent chunks in the packet. When INIT is first, | |
715 | * the normal INIT processing will discard the chunk. | |
716 | */ | |
717 | if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data) | |
718 | goto discard; | |
719 | ||
1da177e4 | 720 | ch = (sctp_chunkhdr_t *) ch_end; |
27a884dc | 721 | } while (ch_end < skb_tail_pointer(skb)); |
1da177e4 LT |
722 | |
723 | return 0; | |
724 | ||
725 | discard: | |
726 | return 1; | |
727 | } | |
728 | ||
729 | /* Insert endpoint into the hash table. */ | |
730 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
731 | { | |
4cdadcbc | 732 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
733 | struct sctp_ep_common *epb; |
734 | struct sctp_hashbucket *head; | |
735 | ||
736 | epb = &ep->base; | |
737 | ||
4cdadcbc | 738 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
739 | head = &sctp_ep_hashtable[epb->hashent]; |
740 | ||
741 | sctp_write_lock(&head->lock); | |
d970dbf8 | 742 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
743 | sctp_write_unlock(&head->lock); |
744 | } | |
745 | ||
746 | /* Add an endpoint to the hash. Local BH-safe. */ | |
747 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
748 | { | |
749 | sctp_local_bh_disable(); | |
750 | __sctp_hash_endpoint(ep); | |
751 | sctp_local_bh_enable(); | |
752 | } | |
753 | ||
754 | /* Remove endpoint from the hash table. */ | |
755 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
756 | { | |
4cdadcbc | 757 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
758 | struct sctp_hashbucket *head; |
759 | struct sctp_ep_common *epb; | |
760 | ||
761 | epb = &ep->base; | |
762 | ||
4cdadcbc | 763 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
764 | |
765 | head = &sctp_ep_hashtable[epb->hashent]; | |
766 | ||
767 | sctp_write_lock(&head->lock); | |
2eebc1e1 | 768 | hlist_del_init(&epb->node); |
1da177e4 LT |
769 | sctp_write_unlock(&head->lock); |
770 | } | |
771 | ||
772 | /* Remove endpoint from the hash. Local BH-safe. */ | |
773 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
774 | { | |
775 | sctp_local_bh_disable(); | |
776 | __sctp_unhash_endpoint(ep); | |
777 | sctp_local_bh_enable(); | |
778 | } | |
779 | ||
780 | /* Look up an endpoint. */ | |
4cdadcbc EB |
781 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net, |
782 | const union sctp_addr *laddr) | |
1da177e4 LT |
783 | { |
784 | struct sctp_hashbucket *head; | |
785 | struct sctp_ep_common *epb; | |
786 | struct sctp_endpoint *ep; | |
d970dbf8 | 787 | struct hlist_node *node; |
1da177e4 LT |
788 | int hash; |
789 | ||
4cdadcbc | 790 | hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
791 | head = &sctp_ep_hashtable[hash]; |
792 | read_lock(&head->lock); | |
d970dbf8 | 793 | sctp_for_each_hentry(epb, node, &head->chain) { |
1da177e4 | 794 | ep = sctp_ep(epb); |
4cdadcbc | 795 | if (sctp_endpoint_is_match(ep, net, laddr)) |
1da177e4 LT |
796 | goto hit; |
797 | } | |
798 | ||
2ce95503 | 799 | ep = sctp_sk(net->sctp.ctl_sock)->ep; |
1da177e4 LT |
800 | |
801 | hit: | |
802 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
803 | read_unlock(&head->lock); |
804 | return ep; | |
805 | } | |
806 | ||
807 | /* Insert association into the hash table. */ | |
808 | static void __sctp_hash_established(struct sctp_association *asoc) | |
809 | { | |
4110cc25 | 810 | struct net *net = sock_net(asoc->base.sk); |
1da177e4 LT |
811 | struct sctp_ep_common *epb; |
812 | struct sctp_hashbucket *head; | |
813 | ||
814 | epb = &asoc->base; | |
815 | ||
816 | /* Calculate which chain this entry will belong to. */ | |
4110cc25 EB |
817 | epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port, |
818 | asoc->peer.port); | |
1da177e4 LT |
819 | |
820 | head = &sctp_assoc_hashtable[epb->hashent]; | |
821 | ||
822 | sctp_write_lock(&head->lock); | |
d970dbf8 | 823 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
824 | sctp_write_unlock(&head->lock); |
825 | } | |
826 | ||
827 | /* Add an association to the hash. Local BH-safe. */ | |
828 | void sctp_hash_established(struct sctp_association *asoc) | |
829 | { | |
de76e695 VY |
830 | if (asoc->temp) |
831 | return; | |
832 | ||
1da177e4 LT |
833 | sctp_local_bh_disable(); |
834 | __sctp_hash_established(asoc); | |
835 | sctp_local_bh_enable(); | |
836 | } | |
837 | ||
838 | /* Remove association from the hash table. */ | |
839 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
840 | { | |
4110cc25 | 841 | struct net *net = sock_net(asoc->base.sk); |
1da177e4 LT |
842 | struct sctp_hashbucket *head; |
843 | struct sctp_ep_common *epb; | |
844 | ||
845 | epb = &asoc->base; | |
846 | ||
4110cc25 | 847 | epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port, |
1da177e4 LT |
848 | asoc->peer.port); |
849 | ||
850 | head = &sctp_assoc_hashtable[epb->hashent]; | |
851 | ||
852 | sctp_write_lock(&head->lock); | |
2eebc1e1 | 853 | hlist_del_init(&epb->node); |
1da177e4 LT |
854 | sctp_write_unlock(&head->lock); |
855 | } | |
856 | ||
857 | /* Remove association from the hash table. Local BH-safe. */ | |
858 | void sctp_unhash_established(struct sctp_association *asoc) | |
859 | { | |
de76e695 VY |
860 | if (asoc->temp) |
861 | return; | |
862 | ||
1da177e4 LT |
863 | sctp_local_bh_disable(); |
864 | __sctp_unhash_established(asoc); | |
865 | sctp_local_bh_enable(); | |
866 | } | |
867 | ||
868 | /* Look up an association. */ | |
869 | static struct sctp_association *__sctp_lookup_association( | |
4110cc25 | 870 | struct net *net, |
1da177e4 LT |
871 | const union sctp_addr *local, |
872 | const union sctp_addr *peer, | |
873 | struct sctp_transport **pt) | |
874 | { | |
875 | struct sctp_hashbucket *head; | |
876 | struct sctp_ep_common *epb; | |
877 | struct sctp_association *asoc; | |
878 | struct sctp_transport *transport; | |
d970dbf8 | 879 | struct hlist_node *node; |
1da177e4 LT |
880 | int hash; |
881 | ||
882 | /* Optimize here for direct hit, only listening connections can | |
883 | * have wildcards anyways. | |
884 | */ | |
4110cc25 EB |
885 | hash = sctp_assoc_hashfn(net, ntohs(local->v4.sin_port), |
886 | ntohs(peer->v4.sin_port)); | |
1da177e4 LT |
887 | head = &sctp_assoc_hashtable[hash]; |
888 | read_lock(&head->lock); | |
d970dbf8 | 889 | sctp_for_each_hentry(epb, node, &head->chain) { |
1da177e4 | 890 | asoc = sctp_assoc(epb); |
4110cc25 | 891 | transport = sctp_assoc_is_match(asoc, net, local, peer); |
1da177e4 LT |
892 | if (transport) |
893 | goto hit; | |
894 | } | |
895 | ||
896 | read_unlock(&head->lock); | |
897 | ||
898 | return NULL; | |
899 | ||
900 | hit: | |
901 | *pt = transport; | |
902 | sctp_association_hold(asoc); | |
1da177e4 LT |
903 | read_unlock(&head->lock); |
904 | return asoc; | |
905 | } | |
906 | ||
907 | /* Look up an association. BH-safe. */ | |
908 | SCTP_STATIC | |
4110cc25 EB |
909 | struct sctp_association *sctp_lookup_association(struct net *net, |
910 | const union sctp_addr *laddr, | |
1da177e4 LT |
911 | const union sctp_addr *paddr, |
912 | struct sctp_transport **transportp) | |
913 | { | |
914 | struct sctp_association *asoc; | |
915 | ||
916 | sctp_local_bh_disable(); | |
4110cc25 | 917 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
1da177e4 LT |
918 | sctp_local_bh_enable(); |
919 | ||
920 | return asoc; | |
921 | } | |
922 | ||
923 | /* Is there an association matching the given local and peer addresses? */ | |
4110cc25 EB |
924 | int sctp_has_association(struct net *net, |
925 | const union sctp_addr *laddr, | |
1da177e4 LT |
926 | const union sctp_addr *paddr) |
927 | { | |
928 | struct sctp_association *asoc; | |
929 | struct sctp_transport *transport; | |
930 | ||
4110cc25 | 931 | if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) { |
1da177e4 LT |
932 | sctp_association_put(asoc); |
933 | return 1; | |
934 | } | |
935 | ||
936 | return 0; | |
937 | } | |
938 | ||
939 | /* | |
940 | * SCTP Implementors Guide, 2.18 Handling of address | |
941 | * parameters within the INIT or INIT-ACK. | |
942 | * | |
943 | * D) When searching for a matching TCB upon reception of an INIT | |
944 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
945 | * source address of the packet (containing the INIT or | |
946 | * INIT-ACK) but the receiver SHOULD also use all valid | |
947 | * address parameters contained within the chunk. | |
948 | * | |
949 | * 2.18.3 Solution description | |
950 | * | |
951 | * This new text clearly specifies to an implementor the need | |
952 | * to look within the INIT or INIT-ACK. Any implementation that | |
953 | * does not do this, may not be able to establish associations | |
954 | * in certain circumstances. | |
955 | * | |
956 | */ | |
4110cc25 EB |
957 | static struct sctp_association *__sctp_rcv_init_lookup(struct net *net, |
958 | struct sk_buff *skb, | |
1da177e4 LT |
959 | const union sctp_addr *laddr, struct sctp_transport **transportp) |
960 | { | |
961 | struct sctp_association *asoc; | |
962 | union sctp_addr addr; | |
963 | union sctp_addr *paddr = &addr; | |
2c0fd387 | 964 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
965 | union sctp_params params; |
966 | sctp_init_chunk_t *init; | |
967 | struct sctp_transport *transport; | |
968 | struct sctp_af *af; | |
969 | ||
1da177e4 LT |
970 | /* |
971 | * This code will NOT touch anything inside the chunk--it is | |
972 | * strictly READ-ONLY. | |
973 | * | |
974 | * RFC 2960 3 SCTP packet Format | |
975 | * | |
976 | * Multiple chunks can be bundled into one SCTP packet up to | |
977 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
978 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
979 | * other chunk in a packet. See Section 6.10 for more details | |
980 | * on chunk bundling. | |
981 | */ | |
982 | ||
983 | /* Find the start of the TLVs and the end of the chunk. This is | |
984 | * the region we search for address parameters. | |
985 | */ | |
986 | init = (sctp_init_chunk_t *)skb->data; | |
987 | ||
988 | /* Walk the parameters looking for embedded addresses. */ | |
989 | sctp_walk_params(params, init, init_hdr.params) { | |
990 | ||
991 | /* Note: Ignoring hostname addresses. */ | |
992 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
993 | if (!af) | |
994 | continue; | |
995 | ||
dd86d136 | 996 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 997 | |
4110cc25 | 998 | asoc = __sctp_lookup_association(net, laddr, paddr, &transport); |
1da177e4 LT |
999 | if (asoc) |
1000 | return asoc; | |
1001 | } | |
1002 | ||
1003 | return NULL; | |
1004 | } | |
1005 | ||
df218577 VY |
1006 | /* ADD-IP, Section 5.2 |
1007 | * When an endpoint receives an ASCONF Chunk from the remote peer | |
1008 | * special procedures may be needed to identify the association the | |
1009 | * ASCONF Chunk is associated with. To properly find the association | |
1010 | * the following procedures SHOULD be followed: | |
1011 | * | |
1012 | * D2) If the association is not found, use the address found in the | |
1013 | * Address Parameter TLV combined with the port number found in the | |
1014 | * SCTP common header. If found proceed to rule D4. | |
1015 | * | |
1016 | * D2-ext) If more than one ASCONF Chunks are packed together, use the | |
1017 | * address found in the ASCONF Address Parameter TLV of each of the | |
1018 | * subsequent ASCONF Chunks. If found, proceed to rule D4. | |
1019 | */ | |
1020 | static struct sctp_association *__sctp_rcv_asconf_lookup( | |
4110cc25 | 1021 | struct net *net, |
df218577 VY |
1022 | sctp_chunkhdr_t *ch, |
1023 | const union sctp_addr *laddr, | |
bc92dd19 | 1024 | __be16 peer_port, |
df218577 VY |
1025 | struct sctp_transport **transportp) |
1026 | { | |
1027 | sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch; | |
1028 | struct sctp_af *af; | |
1029 | union sctp_addr_param *param; | |
1030 | union sctp_addr paddr; | |
1031 | ||
1032 | /* Skip over the ADDIP header and find the Address parameter */ | |
1033 | param = (union sctp_addr_param *)(asconf + 1); | |
1034 | ||
6a435732 | 1035 | af = sctp_get_af_specific(param_type2af(param->p.type)); |
df218577 VY |
1036 | if (unlikely(!af)) |
1037 | return NULL; | |
1038 | ||
1039 | af->from_addr_param(&paddr, param, peer_port, 0); | |
1040 | ||
4110cc25 | 1041 | return __sctp_lookup_association(net, laddr, &paddr, transportp); |
df218577 VY |
1042 | } |
1043 | ||
1044 | ||
bbd0d598 VY |
1045 | /* SCTP-AUTH, Section 6.3: |
1046 | * If the receiver does not find a STCB for a packet containing an AUTH | |
1047 | * chunk as the first chunk and not a COOKIE-ECHO chunk as the second | |
1048 | * chunk, it MUST use the chunks after the AUTH chunk to look up an existing | |
1049 | * association. | |
1050 | * | |
1051 | * This means that any chunks that can help us identify the association need | |
25985edc | 1052 | * to be looked at to find this association. |
bbd0d598 | 1053 | */ |
4110cc25 EB |
1054 | static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net, |
1055 | struct sk_buff *skb, | |
bbd0d598 VY |
1056 | const union sctp_addr *laddr, |
1057 | struct sctp_transport **transportp) | |
1058 | { | |
df218577 VY |
1059 | struct sctp_association *asoc = NULL; |
1060 | sctp_chunkhdr_t *ch; | |
1061 | int have_auth = 0; | |
1062 | unsigned int chunk_num = 1; | |
1063 | __u8 *ch_end; | |
1064 | ||
1065 | /* Walk through the chunks looking for AUTH or ASCONF chunks | |
1066 | * to help us find the association. | |
bbd0d598 | 1067 | */ |
df218577 VY |
1068 | ch = (sctp_chunkhdr_t *) skb->data; |
1069 | do { | |
1070 | /* Break out if chunk length is less then minimal. */ | |
1071 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
1072 | break; | |
1073 | ||
1074 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
1075 | if (ch_end > skb_tail_pointer(skb)) | |
1076 | break; | |
1077 | ||
1078 | switch(ch->type) { | |
1079 | case SCTP_CID_AUTH: | |
1080 | have_auth = chunk_num; | |
1081 | break; | |
1082 | ||
1083 | case SCTP_CID_COOKIE_ECHO: | |
1084 | /* If a packet arrives containing an AUTH chunk as | |
1085 | * a first chunk, a COOKIE-ECHO chunk as the second | |
1086 | * chunk, and possibly more chunks after them, and | |
1087 | * the receiver does not have an STCB for that | |
1088 | * packet, then authentication is based on | |
1089 | * the contents of the COOKIE- ECHO chunk. | |
1090 | */ | |
1091 | if (have_auth == 1 && chunk_num == 2) | |
1092 | return NULL; | |
1093 | break; | |
1094 | ||
1095 | case SCTP_CID_ASCONF: | |
e1fc3b14 | 1096 | if (have_auth || net->sctp.addip_noauth) |
4110cc25 EB |
1097 | asoc = __sctp_rcv_asconf_lookup( |
1098 | net, ch, laddr, | |
df218577 VY |
1099 | sctp_hdr(skb)->source, |
1100 | transportp); | |
1101 | default: | |
1102 | break; | |
1103 | } | |
1104 | ||
1105 | if (asoc) | |
1106 | break; | |
1107 | ||
1108 | ch = (sctp_chunkhdr_t *) ch_end; | |
1109 | chunk_num++; | |
1110 | } while (ch_end < skb_tail_pointer(skb)); | |
1111 | ||
1112 | return asoc; | |
bbd0d598 VY |
1113 | } |
1114 | ||
1115 | /* | |
1116 | * There are circumstances when we need to look inside the SCTP packet | |
1117 | * for information to help us find the association. Examples | |
1118 | * include looking inside of INIT/INIT-ACK chunks or after the AUTH | |
1119 | * chunks. | |
1120 | */ | |
4110cc25 EB |
1121 | static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net, |
1122 | struct sk_buff *skb, | |
bbd0d598 VY |
1123 | const union sctp_addr *laddr, |
1124 | struct sctp_transport **transportp) | |
1125 | { | |
1126 | sctp_chunkhdr_t *ch; | |
1127 | ||
1128 | ch = (sctp_chunkhdr_t *) skb->data; | |
1129 | ||
df218577 VY |
1130 | /* The code below will attempt to walk the chunk and extract |
1131 | * parameter information. Before we do that, we need to verify | |
1132 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
1133 | * walk off the end. | |
1134 | */ | |
1135 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
1136 | return NULL; | |
1137 | ||
bbd0d598 VY |
1138 | /* If this is INIT/INIT-ACK look inside the chunk too. */ |
1139 | switch (ch->type) { | |
1140 | case SCTP_CID_INIT: | |
1141 | case SCTP_CID_INIT_ACK: | |
4110cc25 | 1142 | return __sctp_rcv_init_lookup(net, skb, laddr, transportp); |
bbd0d598 VY |
1143 | break; |
1144 | ||
df218577 | 1145 | default: |
4110cc25 | 1146 | return __sctp_rcv_walk_lookup(net, skb, laddr, transportp); |
bbd0d598 VY |
1147 | break; |
1148 | } | |
1149 | ||
df218577 | 1150 | |
bbd0d598 VY |
1151 | return NULL; |
1152 | } | |
1153 | ||
1da177e4 | 1154 | /* Lookup an association for an inbound skb. */ |
4110cc25 EB |
1155 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
1156 | struct sk_buff *skb, | |
1da177e4 LT |
1157 | const union sctp_addr *paddr, |
1158 | const union sctp_addr *laddr, | |
1159 | struct sctp_transport **transportp) | |
1160 | { | |
1161 | struct sctp_association *asoc; | |
1162 | ||
4110cc25 | 1163 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
1da177e4 LT |
1164 | |
1165 | /* Further lookup for INIT/INIT-ACK packets. | |
1166 | * SCTP Implementors Guide, 2.18 Handling of address | |
1167 | * parameters within the INIT or INIT-ACK. | |
1168 | */ | |
1169 | if (!asoc) | |
4110cc25 | 1170 | asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp); |
1da177e4 LT |
1171 | |
1172 | return asoc; | |
1173 | } |