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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 | |
4b2f13a2 JK |
26 | * along with GNU CC; see the file COPYING. If not, see |
27 | * <http://www.gnu.org/licenses/>. | |
1da177e4 LT |
28 | * |
29 | * Please send any bug reports or fixes you make to the | |
30 | * email address(es): | |
91705c61 | 31 | * lksctp developers <linux-sctp@vger.kernel.org> |
1da177e4 | 32 | * |
1da177e4 LT |
33 | * Written or modified by: |
34 | * La Monte H.P. Yarroll <piggy@acm.org> | |
35 | * Karl Knutson <karl@athena.chicago.il.us> | |
36 | * Xingang Guo <xingang.guo@intel.com> | |
37 | * Jon Grimm <jgrimm@us.ibm.com> | |
38 | * Hui Huang <hui.huang@nokia.com> | |
39 | * Daisy Chang <daisyc@us.ibm.com> | |
40 | * Sridhar Samudrala <sri@us.ibm.com> | |
41 | * Ardelle Fan <ardelle.fan@intel.com> | |
1da177e4 LT |
42 | */ |
43 | ||
44 | #include <linux/types.h> | |
45 | #include <linux/list.h> /* For struct list_head */ | |
46 | #include <linux/socket.h> | |
47 | #include <linux/ip.h> | |
48 | #include <linux/time.h> /* For struct timeval */ | |
5a0e3ad6 | 49 | #include <linux/slab.h> |
1da177e4 LT |
50 | #include <net/ip.h> |
51 | #include <net/icmp.h> | |
52 | #include <net/snmp.h> | |
53 | #include <net/sock.h> | |
54 | #include <net/xfrm.h> | |
55 | #include <net/sctp/sctp.h> | |
56 | #include <net/sctp/sm.h> | |
9ad0977f | 57 | #include <net/sctp/checksum.h> |
dcfc23ca | 58 | #include <net/net_namespace.h> |
1da177e4 LT |
59 | |
60 | /* Forward declarations for internal helpers. */ | |
61 | static int sctp_rcv_ootb(struct sk_buff *); | |
4110cc25 EB |
62 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
63 | struct sk_buff *skb, | |
1da177e4 | 64 | const union sctp_addr *paddr, |
57565993 | 65 | const union sctp_addr *laddr, |
1da177e4 | 66 | struct sctp_transport **transportp); |
4cdadcbc EB |
67 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net, |
68 | const union sctp_addr *laddr); | |
1da177e4 | 69 | static struct sctp_association *__sctp_lookup_association( |
4110cc25 | 70 | struct net *net, |
1da177e4 LT |
71 | const union sctp_addr *local, |
72 | const union sctp_addr *peer, | |
73 | struct sctp_transport **pt); | |
74 | ||
50b1a782 | 75 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb); |
61c9fed4 | 76 | |
1da177e4 LT |
77 | |
78 | /* Calculate the SCTP checksum of an SCTP packet. */ | |
b01a2407 | 79 | static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb) |
1da177e4 | 80 | { |
2c0fd387 | 81 | struct sctphdr *sh = sctp_hdr(skb); |
4458f04c | 82 | __le32 cmp = sh->checksum; |
024ec3de | 83 | __le32 val = sctp_compute_cksum(skb, 0); |
1da177e4 LT |
84 | |
85 | if (val != cmp) { | |
86 | /* CRC failure, dump it. */ | |
b01a2407 | 87 | SCTP_INC_STATS_BH(net, SCTP_MIB_CHECKSUMERRORS); |
1da177e4 LT |
88 | return -1; |
89 | } | |
90 | return 0; | |
91 | } | |
92 | ||
79af02c2 DM |
93 | struct sctp_input_cb { |
94 | union { | |
95 | struct inet_skb_parm h4; | |
dfd56b8b | 96 | #if IS_ENABLED(CONFIG_IPV6) |
79af02c2 DM |
97 | struct inet6_skb_parm h6; |
98 | #endif | |
99 | } header; | |
100 | struct sctp_chunk *chunk; | |
101 | }; | |
102 | #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) | |
103 | ||
1da177e4 LT |
104 | /* |
105 | * This is the routine which IP calls when receiving an SCTP packet. | |
106 | */ | |
107 | int sctp_rcv(struct sk_buff *skb) | |
108 | { | |
109 | struct sock *sk; | |
110 | struct sctp_association *asoc; | |
111 | struct sctp_endpoint *ep = NULL; | |
112 | struct sctp_ep_common *rcvr; | |
113 | struct sctp_transport *transport = NULL; | |
114 | struct sctp_chunk *chunk; | |
115 | struct sctphdr *sh; | |
116 | union sctp_addr src; | |
117 | union sctp_addr dest; | |
118 | int family; | |
119 | struct sctp_af *af; | |
4cdadcbc | 120 | struct net *net = dev_net(skb->dev); |
1da177e4 | 121 | |
cb3f837b | 122 | if (skb->pkt_type != PACKET_HOST) |
1da177e4 LT |
123 | goto discard_it; |
124 | ||
b01a2407 | 125 | SCTP_INC_STATS_BH(net, SCTP_MIB_INSCTPPACKS); |
1da177e4 | 126 | |
28cd7752 HX |
127 | if (skb_linearize(skb)) |
128 | goto discard_it; | |
129 | ||
2c0fd387 | 130 | sh = sctp_hdr(skb); |
1da177e4 LT |
131 | |
132 | /* Pull up the IP and SCTP headers. */ | |
ea2ae17d | 133 | __skb_pull(skb, skb_transport_offset(skb)); |
1da177e4 LT |
134 | if (skb->len < sizeof(struct sctphdr)) |
135 | goto discard_it; | |
71acc0dd DM |
136 | if (!sctp_checksum_disable && !skb_csum_unnecessary(skb) && |
137 | sctp_rcv_checksum(net, skb) < 0) | |
1da177e4 LT |
138 | goto discard_it; |
139 | ||
140 | skb_pull(skb, sizeof(struct sctphdr)); | |
141 | ||
142 | /* Make sure we at least have chunk headers worth of data left. */ | |
143 | if (skb->len < sizeof(struct sctp_chunkhdr)) | |
144 | goto discard_it; | |
145 | ||
eddc9ec5 | 146 | family = ipver2af(ip_hdr(skb)->version); |
1da177e4 LT |
147 | af = sctp_get_af_specific(family); |
148 | if (unlikely(!af)) | |
149 | goto discard_it; | |
150 | ||
151 | /* Initialize local addresses for lookups. */ | |
152 | af->from_skb(&src, skb, 1); | |
153 | af->from_skb(&dest, skb, 0); | |
154 | ||
155 | /* If the packet is to or from a non-unicast address, | |
156 | * silently discard the packet. | |
157 | * | |
158 | * This is not clearly defined in the RFC except in section | |
159 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
160 | * Transmission Protocol" 2.1, "It is important to note that the | |
161 | * IP address of an SCTP transport address must be a routable | |
162 | * unicast address. In other words, IP multicast addresses and | |
163 | * IP broadcast addresses cannot be used in an SCTP transport | |
164 | * address." | |
165 | */ | |
5636bef7 VY |
166 | if (!af->addr_valid(&src, NULL, skb) || |
167 | !af->addr_valid(&dest, NULL, skb)) | |
1da177e4 LT |
168 | goto discard_it; |
169 | ||
4110cc25 | 170 | asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport); |
1c7d1fc1 | 171 | |
0fd9a65a | 172 | if (!asoc) |
4cdadcbc | 173 | ep = __sctp_rcv_lookup_endpoint(net, &dest); |
0fd9a65a NH |
174 | |
175 | /* Retrieve the common input handling substructure. */ | |
176 | rcvr = asoc ? &asoc->base : &ep->base; | |
177 | sk = rcvr->sk; | |
178 | ||
179 | /* | |
180 | * If a frame arrives on an interface and the receiving socket is | |
181 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
182 | */ | |
8d72651d | 183 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) { |
0fd9a65a NH |
184 | if (asoc) { |
185 | sctp_association_put(asoc); | |
186 | asoc = NULL; | |
187 | } else { | |
188 | sctp_endpoint_put(ep); | |
189 | ep = NULL; | |
190 | } | |
2ce95503 | 191 | sk = net->sctp.ctl_sock; |
0fd9a65a NH |
192 | ep = sctp_sk(sk)->ep; |
193 | sctp_endpoint_hold(ep); | |
0fd9a65a NH |
194 | rcvr = &ep->base; |
195 | } | |
196 | ||
1da177e4 LT |
197 | /* |
198 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
199 | * An SCTP packet is called an "out of the blue" (OOTB) | |
200 | * packet if it is correctly formed, i.e., passed the | |
201 | * receiver's checksum check, but the receiver is not | |
202 | * able to identify the association to which this | |
203 | * packet belongs. | |
204 | */ | |
205 | if (!asoc) { | |
1da177e4 | 206 | if (sctp_rcv_ootb(skb)) { |
b01a2407 | 207 | SCTP_INC_STATS_BH(net, SCTP_MIB_OUTOFBLUES); |
1da177e4 LT |
208 | goto discard_release; |
209 | } | |
210 | } | |
211 | ||
1da177e4 LT |
212 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
213 | goto discard_release; | |
b59c2701 | 214 | nf_reset(skb); |
1da177e4 | 215 | |
fda9ef5d | 216 | if (sk_filter(sk, skb)) |
d808ad9a | 217 | goto discard_release; |
1da177e4 LT |
218 | |
219 | /* Create an SCTP packet structure. */ | |
220 | chunk = sctp_chunkify(skb, asoc, sk); | |
2babf9da | 221 | if (!chunk) |
1da177e4 | 222 | goto discard_release; |
79af02c2 | 223 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 224 | |
1da177e4 LT |
225 | /* Remember what endpoint is to handle this packet. */ |
226 | chunk->rcvr = rcvr; | |
227 | ||
228 | /* Remember the SCTP header. */ | |
229 | chunk->sctp_hdr = sh; | |
230 | ||
231 | /* Set the source and destination addresses of the incoming chunk. */ | |
d55c41b1 | 232 | sctp_init_addrs(chunk, &src, &dest); |
1da177e4 LT |
233 | |
234 | /* Remember where we came from. */ | |
235 | chunk->transport = transport; | |
236 | ||
237 | /* Acquire access to the sock lock. Note: We are safe from other | |
238 | * bottom halves on this lock, but a user may be in the lock too, | |
239 | * so check if it is busy. | |
240 | */ | |
5bc1d1b4 | 241 | bh_lock_sock(sk); |
1da177e4 | 242 | |
ae53b5bd VY |
243 | if (sk != rcvr->sk) { |
244 | /* Our cached sk is different from the rcvr->sk. This is | |
245 | * because migrate()/accept() may have moved the association | |
246 | * to a new socket and released all the sockets. So now we | |
247 | * are holding a lock on the old socket while the user may | |
248 | * be doing something with the new socket. Switch our veiw | |
249 | * of the current sk. | |
250 | */ | |
5bc1d1b4 | 251 | bh_unlock_sock(sk); |
ae53b5bd | 252 | sk = rcvr->sk; |
5bc1d1b4 | 253 | bh_lock_sock(sk); |
ae53b5bd VY |
254 | } |
255 | ||
ac0b0462 | 256 | if (sock_owned_by_user(sk)) { |
50b1a782 | 257 | if (sctp_add_backlog(sk, skb)) { |
5bc1d1b4 | 258 | bh_unlock_sock(sk); |
50b1a782 ZY |
259 | sctp_chunk_free(chunk); |
260 | skb = NULL; /* sctp_chunk_free already freed the skb */ | |
261 | goto discard_release; | |
262 | } | |
b01a2407 | 263 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_BACKLOG); |
ac0b0462 | 264 | } else { |
b01a2407 | 265 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_SOFTIRQ); |
61c9fed4 | 266 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 267 | } |
1da177e4 | 268 | |
5bc1d1b4 | 269 | bh_unlock_sock(sk); |
61c9fed4 VY |
270 | |
271 | /* Release the asoc/ep ref we took in the lookup calls. */ | |
272 | if (asoc) | |
273 | sctp_association_put(asoc); | |
274 | else | |
275 | sctp_endpoint_put(ep); | |
7a48f923 | 276 | |
2babf9da | 277 | return 0; |
1da177e4 LT |
278 | |
279 | discard_it: | |
b01a2407 | 280 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_DISCARDS); |
1da177e4 | 281 | kfree_skb(skb); |
2babf9da | 282 | return 0; |
1da177e4 LT |
283 | |
284 | discard_release: | |
61c9fed4 | 285 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 286 | if (asoc) |
1da177e4 | 287 | sctp_association_put(asoc); |
0fd9a65a | 288 | else |
1da177e4 | 289 | sctp_endpoint_put(ep); |
1da177e4 LT |
290 | |
291 | goto discard_it; | |
292 | } | |
293 | ||
61c9fed4 VY |
294 | /* Process the backlog queue of the socket. Every skb on |
295 | * the backlog holds a ref on an association or endpoint. | |
296 | * We hold this ref throughout the state machine to make | |
297 | * sure that the structure we need is still around. | |
1da177e4 LT |
298 | */ |
299 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
300 | { | |
79af02c2 | 301 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
d808ad9a YH |
302 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
303 | struct sctp_ep_common *rcvr = NULL; | |
61c9fed4 | 304 | int backloged = 0; |
7a48f923 | 305 | |
d808ad9a | 306 | rcvr = chunk->rcvr; |
c4d2444e | 307 | |
61c9fed4 VY |
308 | /* If the rcvr is dead then the association or endpoint |
309 | * has been deleted and we can safely drop the chunk | |
310 | * and refs that we are holding. | |
311 | */ | |
312 | if (rcvr->dead) { | |
313 | sctp_chunk_free(chunk); | |
314 | goto done; | |
315 | } | |
316 | ||
317 | if (unlikely(rcvr->sk != sk)) { | |
318 | /* In this case, the association moved from one socket to | |
319 | * another. We are currently sitting on the backlog of the | |
320 | * old socket, so we need to move. | |
321 | * However, since we are here in the process context we | |
322 | * need to take make sure that the user doesn't own | |
323 | * the new socket when we process the packet. | |
324 | * If the new socket is user-owned, queue the chunk to the | |
325 | * backlog of the new socket without dropping any refs. | |
326 | * Otherwise, we can safely push the chunk on the inqueue. | |
327 | */ | |
328 | ||
329 | sk = rcvr->sk; | |
5bc1d1b4 | 330 | bh_lock_sock(sk); |
61c9fed4 VY |
331 | |
332 | if (sock_owned_by_user(sk)) { | |
f545a38f | 333 | if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) |
50b1a782 ZY |
334 | sctp_chunk_free(chunk); |
335 | else | |
336 | backloged = 1; | |
61c9fed4 VY |
337 | } else |
338 | sctp_inq_push(inqueue, chunk); | |
339 | ||
5bc1d1b4 | 340 | bh_unlock_sock(sk); |
61c9fed4 VY |
341 | |
342 | /* If the chunk was backloged again, don't drop refs */ | |
343 | if (backloged) | |
344 | return 0; | |
345 | } else { | |
346 | sctp_inq_push(inqueue, chunk); | |
347 | } | |
348 | ||
349 | done: | |
350 | /* Release the refs we took in sctp_add_backlog */ | |
351 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
352 | sctp_association_put(sctp_assoc(rcvr)); | |
353 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
354 | sctp_endpoint_put(sctp_ep(rcvr)); | |
355 | else | |
356 | BUG(); | |
357 | ||
d808ad9a | 358 | return 0; |
1da177e4 LT |
359 | } |
360 | ||
50b1a782 | 361 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 362 | { |
61c9fed4 VY |
363 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
364 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
50b1a782 | 365 | int ret; |
c4d2444e | 366 | |
f545a38f | 367 | ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf); |
50b1a782 ZY |
368 | if (!ret) { |
369 | /* Hold the assoc/ep while hanging on the backlog queue. | |
370 | * This way, we know structures we need will not disappear | |
371 | * from us | |
372 | */ | |
373 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
374 | sctp_association_hold(sctp_assoc(rcvr)); | |
375 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
376 | sctp_endpoint_hold(sctp_ep(rcvr)); | |
377 | else | |
378 | BUG(); | |
379 | } | |
380 | return ret; | |
61c9fed4 | 381 | |
c4d2444e SS |
382 | } |
383 | ||
1da177e4 LT |
384 | /* Handle icmp frag needed error. */ |
385 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
386 | struct sctp_transport *t, __u32 pmtu) | |
387 | { | |
91bd6b1e | 388 | if (!t || (t->pathmtu <= pmtu)) |
52ccb8e9 FF |
389 | return; |
390 | ||
8a479491 VY |
391 | if (sock_owned_by_user(sk)) { |
392 | asoc->pmtu_pending = 1; | |
393 | t->pmtu_pending = 1; | |
394 | return; | |
395 | } | |
396 | ||
52ccb8e9 | 397 | if (t->param_flags & SPP_PMTUD_ENABLE) { |
c910b47e | 398 | /* Update transports view of the MTU */ |
02f3d4ce | 399 | sctp_transport_update_pmtu(sk, t, pmtu); |
1da177e4 | 400 | |
52ccb8e9 | 401 | /* Update association pmtu. */ |
02f3d4ce | 402 | sctp_assoc_sync_pmtu(sk, asoc); |
1da177e4 | 403 | } |
52ccb8e9 FF |
404 | |
405 | /* Retransmit with the new pmtu setting. | |
406 | * Normally, if PMTU discovery is disabled, an ICMP Fragmentation | |
407 | * Needed will never be sent, but if a message was sent before | |
408 | * PMTU discovery was disabled that was larger than the PMTU, it | |
d808ad9a | 409 | * would not be fragmented, so it must be re-transmitted fragmented. |
52ccb8e9 FF |
410 | */ |
411 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
412 | } |
413 | ||
ec18d9a2 DM |
414 | void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, |
415 | struct sk_buff *skb) | |
55be7a9c DM |
416 | { |
417 | struct dst_entry *dst; | |
418 | ||
419 | if (!t) | |
420 | return; | |
421 | dst = sctp_transport_dst_check(t); | |
1ed5c48f | 422 | if (dst) |
6700c270 | 423 | dst->ops->redirect(dst, sk, skb); |
55be7a9c DM |
424 | } |
425 | ||
1da177e4 LT |
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 | { |
50b5d6ad VY |
441 | if (sock_owned_by_user(sk)) { |
442 | if (timer_pending(&t->proto_unreach_timer)) | |
443 | return; | |
444 | else { | |
445 | if (!mod_timer(&t->proto_unreach_timer, | |
446 | jiffies + (HZ/20))) | |
447 | sctp_association_hold(asoc); | |
448 | } | |
50b5d6ad | 449 | } else { |
55e26eb9 EB |
450 | struct net *net = sock_net(sk); |
451 | ||
bb33381d DB |
452 | pr_debug("%s: unrecognized next header type " |
453 | "encountered!\n", __func__); | |
454 | ||
25cc4ae9 | 455 | if (del_timer(&t->proto_unreach_timer)) |
50b5d6ad | 456 | sctp_association_put(asoc); |
1da177e4 | 457 | |
55e26eb9 | 458 | sctp_do_sm(net, SCTP_EVENT_T_OTHER, |
50b5d6ad VY |
459 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), |
460 | asoc->state, asoc->ep, asoc, t, | |
461 | GFP_ATOMIC); | |
462 | } | |
1da177e4 LT |
463 | } |
464 | ||
465 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
4110cc25 | 466 | struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb, |
1da177e4 | 467 | struct sctphdr *sctphdr, |
1da177e4 LT |
468 | struct sctp_association **app, |
469 | struct sctp_transport **tpp) | |
470 | { | |
471 | union sctp_addr saddr; | |
472 | union sctp_addr daddr; | |
473 | struct sctp_af *af; | |
474 | struct sock *sk = NULL; | |
8de8c873 | 475 | struct sctp_association *asoc; |
1da177e4 | 476 | struct sctp_transport *transport = NULL; |
7115e632 WY |
477 | struct sctp_init_chunk *chunkhdr; |
478 | __u32 vtag = ntohl(sctphdr->vtag); | |
479 | int len = skb->len - ((void *)sctphdr - (void *)skb->data); | |
1da177e4 | 480 | |
d1ad1ff2 | 481 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
482 | |
483 | af = sctp_get_af_specific(family); | |
484 | if (unlikely(!af)) { | |
485 | return NULL; | |
486 | } | |
487 | ||
488 | /* Initialize local addresses for lookups. */ | |
489 | af->from_skb(&saddr, skb, 1); | |
490 | af->from_skb(&daddr, skb, 0); | |
491 | ||
492 | /* Look for an association that matches the incoming ICMP error | |
493 | * packet. | |
494 | */ | |
4110cc25 | 495 | asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport); |
d1ad1ff2 SS |
496 | if (!asoc) |
497 | return NULL; | |
1da177e4 | 498 | |
d1ad1ff2 | 499 | sk = asoc->base.sk; |
1da177e4 | 500 | |
7115e632 WY |
501 | /* RFC 4960, Appendix C. ICMP Handling |
502 | * | |
503 | * ICMP6) An implementation MUST validate that the Verification Tag | |
504 | * contained in the ICMP message matches the Verification Tag of | |
505 | * the peer. If the Verification Tag is not 0 and does NOT | |
506 | * match, discard the ICMP message. If it is 0 and the ICMP | |
507 | * message contains enough bytes to verify that the chunk type is | |
508 | * an INIT chunk and that the Initiate Tag matches the tag of the | |
509 | * peer, continue with ICMP7. If the ICMP message is too short | |
510 | * or the chunk type or the Initiate Tag does not match, silently | |
511 | * discard the packet. | |
512 | */ | |
513 | if (vtag == 0) { | |
ea110733 | 514 | chunkhdr = (void *)sctphdr + sizeof(struct sctphdr); |
7115e632 WY |
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 | 524 | |
5bc1d1b4 | 525 | bh_lock_sock(sk); |
1da177e4 LT |
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)) | |
b01a2407 | 531 | NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); |
1da177e4 | 532 | |
1da177e4 LT |
533 | *app = asoc; |
534 | *tpp = transport; | |
535 | return sk; | |
536 | ||
537 | out: | |
e4772668 | 538 | sctp_association_put(asoc); |
1da177e4 LT |
539 | return NULL; |
540 | } | |
541 | ||
542 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 543 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 | 544 | { |
5bc1d1b4 | 545 | bh_unlock_sock(sk); |
e4772668 | 546 | sctp_association_put(asoc); |
1da177e4 LT |
547 | } |
548 | ||
549 | /* | |
550 | * This routine is called by the ICMP module when it gets some | |
551 | * sort of error condition. If err < 0 then the socket should | |
552 | * be closed and the error returned to the user. If err > 0 | |
553 | * it's just the icmp type << 8 | icmp code. After adjustment | |
554 | * header points to the first 8 bytes of the sctp header. We need | |
555 | * to find the appropriate port. | |
556 | * | |
557 | * The locking strategy used here is very "optimistic". When | |
558 | * someone else accesses the socket the ICMP is just dropped | |
559 | * and for some paths there is no check at all. | |
560 | * A more general error queue to queue errors for later handling | |
561 | * is probably better. | |
562 | * | |
563 | */ | |
564 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
565 | { | |
b71d1d42 | 566 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
a27ef749 | 567 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
568 | const int type = icmp_hdr(skb)->type; |
569 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 570 | struct sock *sk; |
8de8c873 | 571 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
572 | struct sctp_transport *transport; |
573 | struct inet_sock *inet; | |
aef6de51 | 574 | __u16 saveip, savesctp; |
1da177e4 | 575 | int err; |
4110cc25 | 576 | struct net *net = dev_net(skb->dev); |
1da177e4 | 577 | |
a27ef749 | 578 | if (skb->len < ihlen + 8) { |
b01a2407 | 579 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
580 | return; |
581 | } | |
582 | ||
583 | /* Fix up skb to look at the embedded net header. */ | |
b0e380b1 ACM |
584 | saveip = skb->network_header; |
585 | savesctp = skb->transport_header; | |
31c7711b | 586 | skb_reset_network_header(skb); |
a27ef749 | 587 | skb_set_transport_header(skb, ihlen); |
4110cc25 | 588 | sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport); |
2e07fa9c | 589 | /* Put back, the original values. */ |
b0e380b1 ACM |
590 | skb->network_header = saveip; |
591 | skb->transport_header = savesctp; | |
1da177e4 | 592 | if (!sk) { |
b01a2407 | 593 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
594 | return; |
595 | } | |
596 | /* Warning: The sock lock is held. Remember to call | |
597 | * sctp_err_finish! | |
598 | */ | |
599 | ||
600 | switch (type) { | |
601 | case ICMP_PARAMETERPROB: | |
602 | err = EPROTO; | |
603 | break; | |
604 | case ICMP_DEST_UNREACH: | |
605 | if (code > NR_ICMP_UNREACH) | |
606 | goto out_unlock; | |
607 | ||
608 | /* PMTU discovery (RFC1191) */ | |
609 | if (ICMP_FRAG_NEEDED == code) { | |
610 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
611 | goto out_unlock; | |
8d72651d | 612 | } else { |
1da177e4 | 613 | if (ICMP_PROT_UNREACH == code) { |
d1ad1ff2 | 614 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
615 | transport); |
616 | goto out_unlock; | |
617 | } | |
618 | } | |
619 | err = icmp_err_convert[code].errno; | |
620 | break; | |
621 | case ICMP_TIME_EXCEEDED: | |
622 | /* Ignore any time exceeded errors due to fragment reassembly | |
623 | * timeouts. | |
624 | */ | |
625 | if (ICMP_EXC_FRAGTIME == code) | |
626 | goto out_unlock; | |
627 | ||
628 | err = EHOSTUNREACH; | |
629 | break; | |
55be7a9c DM |
630 | case ICMP_REDIRECT: |
631 | sctp_icmp_redirect(sk, transport, skb); | |
3f96a532 | 632 | /* Fall through to out_unlock. */ |
1da177e4 LT |
633 | default: |
634 | goto out_unlock; | |
635 | } | |
636 | ||
637 | inet = inet_sk(sk); | |
638 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
639 | sk->sk_err = err; | |
640 | sk->sk_error_report(sk); | |
641 | } else { /* Only an error on timeout */ | |
642 | sk->sk_err_soft = err; | |
643 | } | |
644 | ||
645 | out_unlock: | |
d1ad1ff2 | 646 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
647 | } |
648 | ||
649 | /* | |
650 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
651 | * | |
652 | * This function scans all the chunks in the OOTB packet to determine if | |
653 | * the packet should be discarded right away. If a response might be needed | |
654 | * for this packet, or, if further processing is possible, the packet will | |
655 | * be queued to a proper inqueue for the next phase of handling. | |
656 | * | |
657 | * Output: | |
658 | * Return 0 - If further processing is needed. | |
659 | * Return 1 - If the packet can be discarded right away. | |
660 | */ | |
04675210 | 661 | static int sctp_rcv_ootb(struct sk_buff *skb) |
1da177e4 LT |
662 | { |
663 | sctp_chunkhdr_t *ch; | |
664 | __u8 *ch_end; | |
1da177e4 LT |
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 | 700 | ch = (sctp_chunkhdr_t *) ch_end; |
27a884dc | 701 | } while (ch_end < skb_tail_pointer(skb)); |
1da177e4 LT |
702 | |
703 | return 0; | |
704 | ||
705 | discard: | |
706 | return 1; | |
707 | } | |
708 | ||
709 | /* Insert endpoint into the hash table. */ | |
710 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
711 | { | |
4cdadcbc | 712 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
713 | struct sctp_ep_common *epb; |
714 | struct sctp_hashbucket *head; | |
715 | ||
716 | epb = &ep->base; | |
717 | ||
4cdadcbc | 718 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
719 | head = &sctp_ep_hashtable[epb->hashent]; |
720 | ||
387602df | 721 | write_lock(&head->lock); |
d970dbf8 | 722 | hlist_add_head(&epb->node, &head->chain); |
387602df | 723 | write_unlock(&head->lock); |
1da177e4 LT |
724 | } |
725 | ||
726 | /* Add an endpoint to the hash. Local BH-safe. */ | |
727 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
728 | { | |
79b91130 | 729 | local_bh_disable(); |
1da177e4 | 730 | __sctp_hash_endpoint(ep); |
79b91130 | 731 | local_bh_enable(); |
1da177e4 LT |
732 | } |
733 | ||
734 | /* Remove endpoint from the hash table. */ | |
735 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
736 | { | |
4cdadcbc | 737 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
738 | struct sctp_hashbucket *head; |
739 | struct sctp_ep_common *epb; | |
740 | ||
741 | epb = &ep->base; | |
742 | ||
4cdadcbc | 743 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
744 | |
745 | head = &sctp_ep_hashtable[epb->hashent]; | |
746 | ||
387602df | 747 | write_lock(&head->lock); |
2eebc1e1 | 748 | hlist_del_init(&epb->node); |
387602df | 749 | write_unlock(&head->lock); |
1da177e4 LT |
750 | } |
751 | ||
752 | /* Remove endpoint from the hash. Local BH-safe. */ | |
753 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
754 | { | |
79b91130 | 755 | local_bh_disable(); |
1da177e4 | 756 | __sctp_unhash_endpoint(ep); |
79b91130 | 757 | local_bh_enable(); |
1da177e4 LT |
758 | } |
759 | ||
760 | /* Look up an endpoint. */ | |
4cdadcbc EB |
761 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net, |
762 | const union sctp_addr *laddr) | |
1da177e4 LT |
763 | { |
764 | struct sctp_hashbucket *head; | |
765 | struct sctp_ep_common *epb; | |
766 | struct sctp_endpoint *ep; | |
767 | int hash; | |
768 | ||
4cdadcbc | 769 | hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
770 | head = &sctp_ep_hashtable[hash]; |
771 | read_lock(&head->lock); | |
b67bfe0d | 772 | sctp_for_each_hentry(epb, &head->chain) { |
1da177e4 | 773 | ep = sctp_ep(epb); |
4cdadcbc | 774 | if (sctp_endpoint_is_match(ep, net, laddr)) |
1da177e4 LT |
775 | goto hit; |
776 | } | |
777 | ||
2ce95503 | 778 | ep = sctp_sk(net->sctp.ctl_sock)->ep; |
1da177e4 LT |
779 | |
780 | hit: | |
781 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
782 | read_unlock(&head->lock); |
783 | return ep; | |
784 | } | |
785 | ||
786 | /* Insert association into the hash table. */ | |
787 | static void __sctp_hash_established(struct sctp_association *asoc) | |
788 | { | |
4110cc25 | 789 | struct net *net = sock_net(asoc->base.sk); |
1da177e4 LT |
790 | struct sctp_ep_common *epb; |
791 | struct sctp_hashbucket *head; | |
792 | ||
793 | epb = &asoc->base; | |
794 | ||
795 | /* Calculate which chain this entry will belong to. */ | |
4110cc25 EB |
796 | epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port, |
797 | asoc->peer.port); | |
1da177e4 LT |
798 | |
799 | head = &sctp_assoc_hashtable[epb->hashent]; | |
800 | ||
387602df | 801 | write_lock(&head->lock); |
d970dbf8 | 802 | hlist_add_head(&epb->node, &head->chain); |
387602df | 803 | write_unlock(&head->lock); |
1da177e4 LT |
804 | } |
805 | ||
806 | /* Add an association to the hash. Local BH-safe. */ | |
807 | void sctp_hash_established(struct sctp_association *asoc) | |
808 | { | |
de76e695 VY |
809 | if (asoc->temp) |
810 | return; | |
811 | ||
79b91130 | 812 | local_bh_disable(); |
1da177e4 | 813 | __sctp_hash_established(asoc); |
79b91130 | 814 | local_bh_enable(); |
1da177e4 LT |
815 | } |
816 | ||
817 | /* Remove association from the hash table. */ | |
818 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
819 | { | |
4110cc25 | 820 | struct net *net = sock_net(asoc->base.sk); |
1da177e4 LT |
821 | struct sctp_hashbucket *head; |
822 | struct sctp_ep_common *epb; | |
823 | ||
824 | epb = &asoc->base; | |
825 | ||
4110cc25 | 826 | epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port, |
1da177e4 LT |
827 | asoc->peer.port); |
828 | ||
829 | head = &sctp_assoc_hashtable[epb->hashent]; | |
830 | ||
387602df | 831 | write_lock(&head->lock); |
2eebc1e1 | 832 | hlist_del_init(&epb->node); |
387602df | 833 | write_unlock(&head->lock); |
1da177e4 LT |
834 | } |
835 | ||
836 | /* Remove association from the hash table. Local BH-safe. */ | |
837 | void sctp_unhash_established(struct sctp_association *asoc) | |
838 | { | |
de76e695 VY |
839 | if (asoc->temp) |
840 | return; | |
841 | ||
79b91130 | 842 | local_bh_disable(); |
1da177e4 | 843 | __sctp_unhash_established(asoc); |
79b91130 | 844 | local_bh_enable(); |
1da177e4 LT |
845 | } |
846 | ||
847 | /* Look up an association. */ | |
848 | static struct sctp_association *__sctp_lookup_association( | |
4110cc25 | 849 | struct net *net, |
1da177e4 LT |
850 | const union sctp_addr *local, |
851 | const union sctp_addr *peer, | |
852 | struct sctp_transport **pt) | |
853 | { | |
854 | struct sctp_hashbucket *head; | |
855 | struct sctp_ep_common *epb; | |
856 | struct sctp_association *asoc; | |
857 | struct sctp_transport *transport; | |
858 | int hash; | |
859 | ||
860 | /* Optimize here for direct hit, only listening connections can | |
861 | * have wildcards anyways. | |
862 | */ | |
4110cc25 EB |
863 | hash = sctp_assoc_hashfn(net, ntohs(local->v4.sin_port), |
864 | ntohs(peer->v4.sin_port)); | |
1da177e4 LT |
865 | head = &sctp_assoc_hashtable[hash]; |
866 | read_lock(&head->lock); | |
b67bfe0d | 867 | sctp_for_each_hentry(epb, &head->chain) { |
1da177e4 | 868 | asoc = sctp_assoc(epb); |
4110cc25 | 869 | transport = sctp_assoc_is_match(asoc, net, local, peer); |
1da177e4 LT |
870 | if (transport) |
871 | goto hit; | |
872 | } | |
873 | ||
874 | read_unlock(&head->lock); | |
875 | ||
876 | return NULL; | |
877 | ||
878 | hit: | |
879 | *pt = transport; | |
880 | sctp_association_hold(asoc); | |
1da177e4 LT |
881 | read_unlock(&head->lock); |
882 | return asoc; | |
883 | } | |
884 | ||
885 | /* Look up an association. BH-safe. */ | |
dda91928 | 886 | static |
4110cc25 EB |
887 | struct sctp_association *sctp_lookup_association(struct net *net, |
888 | const union sctp_addr *laddr, | |
1da177e4 | 889 | const union sctp_addr *paddr, |
dda91928 | 890 | struct sctp_transport **transportp) |
1da177e4 LT |
891 | { |
892 | struct sctp_association *asoc; | |
893 | ||
79b91130 | 894 | local_bh_disable(); |
4110cc25 | 895 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
79b91130 | 896 | local_bh_enable(); |
1da177e4 LT |
897 | |
898 | return asoc; | |
899 | } | |
900 | ||
901 | /* Is there an association matching the given local and peer addresses? */ | |
4110cc25 EB |
902 | int sctp_has_association(struct net *net, |
903 | const union sctp_addr *laddr, | |
1da177e4 LT |
904 | const union sctp_addr *paddr) |
905 | { | |
906 | struct sctp_association *asoc; | |
907 | struct sctp_transport *transport; | |
908 | ||
4110cc25 | 909 | if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) { |
1da177e4 LT |
910 | sctp_association_put(asoc); |
911 | return 1; | |
912 | } | |
913 | ||
914 | return 0; | |
915 | } | |
916 | ||
917 | /* | |
918 | * SCTP Implementors Guide, 2.18 Handling of address | |
919 | * parameters within the INIT or INIT-ACK. | |
920 | * | |
921 | * D) When searching for a matching TCB upon reception of an INIT | |
922 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
923 | * source address of the packet (containing the INIT or | |
924 | * INIT-ACK) but the receiver SHOULD also use all valid | |
925 | * address parameters contained within the chunk. | |
926 | * | |
927 | * 2.18.3 Solution description | |
928 | * | |
929 | * This new text clearly specifies to an implementor the need | |
930 | * to look within the INIT or INIT-ACK. Any implementation that | |
931 | * does not do this, may not be able to establish associations | |
932 | * in certain circumstances. | |
933 | * | |
934 | */ | |
4110cc25 EB |
935 | static struct sctp_association *__sctp_rcv_init_lookup(struct net *net, |
936 | struct sk_buff *skb, | |
1da177e4 LT |
937 | const union sctp_addr *laddr, struct sctp_transport **transportp) |
938 | { | |
939 | struct sctp_association *asoc; | |
940 | union sctp_addr addr; | |
941 | union sctp_addr *paddr = &addr; | |
2c0fd387 | 942 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
943 | union sctp_params params; |
944 | sctp_init_chunk_t *init; | |
945 | struct sctp_transport *transport; | |
946 | struct sctp_af *af; | |
947 | ||
1da177e4 LT |
948 | /* |
949 | * This code will NOT touch anything inside the chunk--it is | |
950 | * strictly READ-ONLY. | |
951 | * | |
952 | * RFC 2960 3 SCTP packet Format | |
953 | * | |
954 | * Multiple chunks can be bundled into one SCTP packet up to | |
955 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
956 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
957 | * other chunk in a packet. See Section 6.10 for more details | |
958 | * on chunk bundling. | |
959 | */ | |
960 | ||
961 | /* Find the start of the TLVs and the end of the chunk. This is | |
962 | * the region we search for address parameters. | |
963 | */ | |
964 | init = (sctp_init_chunk_t *)skb->data; | |
965 | ||
966 | /* Walk the parameters looking for embedded addresses. */ | |
967 | sctp_walk_params(params, init, init_hdr.params) { | |
968 | ||
969 | /* Note: Ignoring hostname addresses. */ | |
970 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
971 | if (!af) | |
972 | continue; | |
973 | ||
dd86d136 | 974 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 975 | |
4110cc25 | 976 | asoc = __sctp_lookup_association(net, laddr, paddr, &transport); |
1da177e4 LT |
977 | if (asoc) |
978 | return asoc; | |
979 | } | |
980 | ||
981 | return NULL; | |
982 | } | |
983 | ||
df218577 VY |
984 | /* ADD-IP, Section 5.2 |
985 | * When an endpoint receives an ASCONF Chunk from the remote peer | |
986 | * special procedures may be needed to identify the association the | |
987 | * ASCONF Chunk is associated with. To properly find the association | |
988 | * the following procedures SHOULD be followed: | |
989 | * | |
990 | * D2) If the association is not found, use the address found in the | |
991 | * Address Parameter TLV combined with the port number found in the | |
992 | * SCTP common header. If found proceed to rule D4. | |
993 | * | |
994 | * D2-ext) If more than one ASCONF Chunks are packed together, use the | |
995 | * address found in the ASCONF Address Parameter TLV of each of the | |
996 | * subsequent ASCONF Chunks. If found, proceed to rule D4. | |
997 | */ | |
998 | static struct sctp_association *__sctp_rcv_asconf_lookup( | |
4110cc25 | 999 | struct net *net, |
df218577 VY |
1000 | sctp_chunkhdr_t *ch, |
1001 | const union sctp_addr *laddr, | |
bc92dd19 | 1002 | __be16 peer_port, |
df218577 VY |
1003 | struct sctp_transport **transportp) |
1004 | { | |
1005 | sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch; | |
1006 | struct sctp_af *af; | |
1007 | union sctp_addr_param *param; | |
1008 | union sctp_addr paddr; | |
1009 | ||
1010 | /* Skip over the ADDIP header and find the Address parameter */ | |
1011 | param = (union sctp_addr_param *)(asconf + 1); | |
1012 | ||
6a435732 | 1013 | af = sctp_get_af_specific(param_type2af(param->p.type)); |
df218577 VY |
1014 | if (unlikely(!af)) |
1015 | return NULL; | |
1016 | ||
1017 | af->from_addr_param(&paddr, param, peer_port, 0); | |
1018 | ||
4110cc25 | 1019 | return __sctp_lookup_association(net, laddr, &paddr, transportp); |
df218577 VY |
1020 | } |
1021 | ||
1022 | ||
bbd0d598 VY |
1023 | /* SCTP-AUTH, Section 6.3: |
1024 | * If the receiver does not find a STCB for a packet containing an AUTH | |
1025 | * chunk as the first chunk and not a COOKIE-ECHO chunk as the second | |
1026 | * chunk, it MUST use the chunks after the AUTH chunk to look up an existing | |
1027 | * association. | |
1028 | * | |
1029 | * This means that any chunks that can help us identify the association need | |
25985edc | 1030 | * to be looked at to find this association. |
bbd0d598 | 1031 | */ |
4110cc25 EB |
1032 | static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net, |
1033 | struct sk_buff *skb, | |
bbd0d598 VY |
1034 | const union sctp_addr *laddr, |
1035 | struct sctp_transport **transportp) | |
1036 | { | |
df218577 VY |
1037 | struct sctp_association *asoc = NULL; |
1038 | sctp_chunkhdr_t *ch; | |
1039 | int have_auth = 0; | |
1040 | unsigned int chunk_num = 1; | |
1041 | __u8 *ch_end; | |
1042 | ||
1043 | /* Walk through the chunks looking for AUTH or ASCONF chunks | |
1044 | * to help us find the association. | |
bbd0d598 | 1045 | */ |
df218577 VY |
1046 | ch = (sctp_chunkhdr_t *) skb->data; |
1047 | do { | |
1048 | /* Break out if chunk length is less then minimal. */ | |
1049 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
1050 | break; | |
1051 | ||
1052 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
1053 | if (ch_end > skb_tail_pointer(skb)) | |
1054 | break; | |
1055 | ||
cb3f837b | 1056 | switch (ch->type) { |
f7010e61 | 1057 | case SCTP_CID_AUTH: |
1058 | have_auth = chunk_num; | |
1059 | break; | |
1060 | ||
1061 | case SCTP_CID_COOKIE_ECHO: | |
1062 | /* If a packet arrives containing an AUTH chunk as | |
1063 | * a first chunk, a COOKIE-ECHO chunk as the second | |
1064 | * chunk, and possibly more chunks after them, and | |
1065 | * the receiver does not have an STCB for that | |
1066 | * packet, then authentication is based on | |
1067 | * the contents of the COOKIE- ECHO chunk. | |
1068 | */ | |
1069 | if (have_auth == 1 && chunk_num == 2) | |
1070 | return NULL; | |
1071 | break; | |
1072 | ||
1073 | case SCTP_CID_ASCONF: | |
1074 | if (have_auth || net->sctp.addip_noauth) | |
1075 | asoc = __sctp_rcv_asconf_lookup( | |
1076 | net, ch, laddr, | |
1077 | sctp_hdr(skb)->source, | |
1078 | transportp); | |
1079 | default: | |
1080 | break; | |
df218577 VY |
1081 | } |
1082 | ||
1083 | if (asoc) | |
1084 | break; | |
1085 | ||
1086 | ch = (sctp_chunkhdr_t *) ch_end; | |
1087 | chunk_num++; | |
1088 | } while (ch_end < skb_tail_pointer(skb)); | |
1089 | ||
1090 | return asoc; | |
bbd0d598 VY |
1091 | } |
1092 | ||
1093 | /* | |
1094 | * There are circumstances when we need to look inside the SCTP packet | |
1095 | * for information to help us find the association. Examples | |
1096 | * include looking inside of INIT/INIT-ACK chunks or after the AUTH | |
1097 | * chunks. | |
1098 | */ | |
4110cc25 EB |
1099 | static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net, |
1100 | struct sk_buff *skb, | |
bbd0d598 VY |
1101 | const union sctp_addr *laddr, |
1102 | struct sctp_transport **transportp) | |
1103 | { | |
1104 | sctp_chunkhdr_t *ch; | |
1105 | ||
1106 | ch = (sctp_chunkhdr_t *) skb->data; | |
1107 | ||
df218577 VY |
1108 | /* The code below will attempt to walk the chunk and extract |
1109 | * parameter information. Before we do that, we need to verify | |
1110 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
1111 | * walk off the end. | |
1112 | */ | |
1113 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
1114 | return NULL; | |
1115 | ||
bbd0d598 | 1116 | /* If this is INIT/INIT-ACK look inside the chunk too. */ |
f482f2fc | 1117 | if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK) |
4110cc25 | 1118 | return __sctp_rcv_init_lookup(net, skb, laddr, transportp); |
bbd0d598 | 1119 | |
f482f2fc | 1120 | return __sctp_rcv_walk_lookup(net, skb, laddr, transportp); |
bbd0d598 VY |
1121 | } |
1122 | ||
1da177e4 | 1123 | /* Lookup an association for an inbound skb. */ |
4110cc25 EB |
1124 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
1125 | struct sk_buff *skb, | |
1da177e4 LT |
1126 | const union sctp_addr *paddr, |
1127 | const union sctp_addr *laddr, | |
1128 | struct sctp_transport **transportp) | |
1129 | { | |
1130 | struct sctp_association *asoc; | |
1131 | ||
4110cc25 | 1132 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
1da177e4 LT |
1133 | |
1134 | /* Further lookup for INIT/INIT-ACK packets. | |
1135 | * SCTP Implementors Guide, 2.18 Handling of address | |
1136 | * parameters within the INIT or INIT-ACK. | |
1137 | */ | |
1138 | if (!asoc) | |
4110cc25 | 1139 | asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp); |
1da177e4 LT |
1140 | |
1141 | return asoc; | |
1142 | } |