Commit | Line | Data |
---|---|---|
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 | */ | |
183 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) | |
184 | { | |
0fd9a65a NH |
185 | if (asoc) { |
186 | sctp_association_put(asoc); | |
187 | asoc = NULL; | |
188 | } else { | |
189 | sctp_endpoint_put(ep); | |
190 | ep = NULL; | |
191 | } | |
2ce95503 | 192 | sk = net->sctp.ctl_sock; |
0fd9a65a NH |
193 | ep = sctp_sk(sk)->ep; |
194 | sctp_endpoint_hold(ep); | |
0fd9a65a NH |
195 | rcvr = &ep->base; |
196 | } | |
197 | ||
1da177e4 LT |
198 | /* |
199 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
200 | * An SCTP packet is called an "out of the blue" (OOTB) | |
201 | * packet if it is correctly formed, i.e., passed the | |
202 | * receiver's checksum check, but the receiver is not | |
203 | * able to identify the association to which this | |
204 | * packet belongs. | |
205 | */ | |
206 | if (!asoc) { | |
1da177e4 | 207 | if (sctp_rcv_ootb(skb)) { |
b01a2407 | 208 | SCTP_INC_STATS_BH(net, SCTP_MIB_OUTOFBLUES); |
1da177e4 LT |
209 | goto discard_release; |
210 | } | |
211 | } | |
212 | ||
1da177e4 LT |
213 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
214 | goto discard_release; | |
b59c2701 | 215 | nf_reset(skb); |
1da177e4 | 216 | |
fda9ef5d | 217 | if (sk_filter(sk, skb)) |
d808ad9a | 218 | goto discard_release; |
1da177e4 LT |
219 | |
220 | /* Create an SCTP packet structure. */ | |
221 | chunk = sctp_chunkify(skb, asoc, sk); | |
2babf9da | 222 | if (!chunk) |
1da177e4 | 223 | goto discard_release; |
79af02c2 | 224 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 225 | |
1da177e4 LT |
226 | /* Remember what endpoint is to handle this packet. */ |
227 | chunk->rcvr = rcvr; | |
228 | ||
229 | /* Remember the SCTP header. */ | |
230 | chunk->sctp_hdr = sh; | |
231 | ||
232 | /* Set the source and destination addresses of the incoming chunk. */ | |
d55c41b1 | 233 | sctp_init_addrs(chunk, &src, &dest); |
1da177e4 LT |
234 | |
235 | /* Remember where we came from. */ | |
236 | chunk->transport = transport; | |
237 | ||
238 | /* Acquire access to the sock lock. Note: We are safe from other | |
239 | * bottom halves on this lock, but a user may be in the lock too, | |
240 | * so check if it is busy. | |
241 | */ | |
242 | sctp_bh_lock_sock(sk); | |
243 | ||
ae53b5bd VY |
244 | if (sk != rcvr->sk) { |
245 | /* Our cached sk is different from the rcvr->sk. This is | |
246 | * because migrate()/accept() may have moved the association | |
247 | * to a new socket and released all the sockets. So now we | |
248 | * are holding a lock on the old socket while the user may | |
249 | * be doing something with the new socket. Switch our veiw | |
250 | * of the current sk. | |
251 | */ | |
252 | sctp_bh_unlock_sock(sk); | |
253 | sk = rcvr->sk; | |
254 | sctp_bh_lock_sock(sk); | |
255 | } | |
256 | ||
ac0b0462 | 257 | if (sock_owned_by_user(sk)) { |
50b1a782 ZY |
258 | if (sctp_add_backlog(sk, skb)) { |
259 | sctp_bh_unlock_sock(sk); | |
260 | sctp_chunk_free(chunk); | |
261 | skb = NULL; /* sctp_chunk_free already freed the skb */ | |
262 | goto discard_release; | |
263 | } | |
b01a2407 | 264 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_BACKLOG); |
ac0b0462 | 265 | } else { |
b01a2407 | 266 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_SOFTIRQ); |
61c9fed4 | 267 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 268 | } |
1da177e4 | 269 | |
1da177e4 | 270 | sctp_bh_unlock_sock(sk); |
61c9fed4 VY |
271 | |
272 | /* Release the asoc/ep ref we took in the lookup calls. */ | |
273 | if (asoc) | |
274 | sctp_association_put(asoc); | |
275 | else | |
276 | sctp_endpoint_put(ep); | |
7a48f923 | 277 | |
2babf9da | 278 | return 0; |
1da177e4 LT |
279 | |
280 | discard_it: | |
b01a2407 | 281 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_DISCARDS); |
1da177e4 | 282 | kfree_skb(skb); |
2babf9da | 283 | return 0; |
1da177e4 LT |
284 | |
285 | discard_release: | |
61c9fed4 | 286 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 287 | if (asoc) |
1da177e4 | 288 | sctp_association_put(asoc); |
0fd9a65a | 289 | else |
1da177e4 | 290 | sctp_endpoint_put(ep); |
1da177e4 LT |
291 | |
292 | goto discard_it; | |
293 | } | |
294 | ||
61c9fed4 VY |
295 | /* Process the backlog queue of the socket. Every skb on |
296 | * the backlog holds a ref on an association or endpoint. | |
297 | * We hold this ref throughout the state machine to make | |
298 | * sure that the structure we need is still around. | |
1da177e4 LT |
299 | */ |
300 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
301 | { | |
79af02c2 | 302 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
d808ad9a YH |
303 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
304 | struct sctp_ep_common *rcvr = NULL; | |
61c9fed4 | 305 | int backloged = 0; |
7a48f923 | 306 | |
d808ad9a | 307 | rcvr = chunk->rcvr; |
c4d2444e | 308 | |
61c9fed4 VY |
309 | /* If the rcvr is dead then the association or endpoint |
310 | * has been deleted and we can safely drop the chunk | |
311 | * and refs that we are holding. | |
312 | */ | |
313 | if (rcvr->dead) { | |
314 | sctp_chunk_free(chunk); | |
315 | goto done; | |
316 | } | |
317 | ||
318 | if (unlikely(rcvr->sk != sk)) { | |
319 | /* In this case, the association moved from one socket to | |
320 | * another. We are currently sitting on the backlog of the | |
321 | * old socket, so we need to move. | |
322 | * However, since we are here in the process context we | |
323 | * need to take make sure that the user doesn't own | |
324 | * the new socket when we process the packet. | |
325 | * If the new socket is user-owned, queue the chunk to the | |
326 | * backlog of the new socket without dropping any refs. | |
327 | * Otherwise, we can safely push the chunk on the inqueue. | |
328 | */ | |
329 | ||
330 | sk = rcvr->sk; | |
331 | sctp_bh_lock_sock(sk); | |
332 | ||
333 | if (sock_owned_by_user(sk)) { | |
f545a38f | 334 | if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) |
50b1a782 ZY |
335 | sctp_chunk_free(chunk); |
336 | else | |
337 | backloged = 1; | |
61c9fed4 VY |
338 | } else |
339 | sctp_inq_push(inqueue, chunk); | |
340 | ||
341 | sctp_bh_unlock_sock(sk); | |
342 | ||
343 | /* If the chunk was backloged again, don't drop refs */ | |
344 | if (backloged) | |
345 | return 0; | |
346 | } else { | |
347 | sctp_inq_push(inqueue, chunk); | |
348 | } | |
349 | ||
350 | done: | |
351 | /* Release the refs we took in sctp_add_backlog */ | |
352 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
353 | sctp_association_put(sctp_assoc(rcvr)); | |
354 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
355 | sctp_endpoint_put(sctp_ep(rcvr)); | |
356 | else | |
357 | BUG(); | |
358 | ||
d808ad9a | 359 | return 0; |
1da177e4 LT |
360 | } |
361 | ||
50b1a782 | 362 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 363 | { |
61c9fed4 VY |
364 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
365 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
50b1a782 | 366 | int ret; |
c4d2444e | 367 | |
f545a38f | 368 | ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf); |
50b1a782 ZY |
369 | if (!ret) { |
370 | /* Hold the assoc/ep while hanging on the backlog queue. | |
371 | * This way, we know structures we need will not disappear | |
372 | * from us | |
373 | */ | |
374 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
375 | sctp_association_hold(sctp_assoc(rcvr)); | |
376 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
377 | sctp_endpoint_hold(sctp_ep(rcvr)); | |
378 | else | |
379 | BUG(); | |
380 | } | |
381 | return ret; | |
61c9fed4 | 382 | |
c4d2444e SS |
383 | } |
384 | ||
1da177e4 LT |
385 | /* Handle icmp frag needed error. */ |
386 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
387 | struct sctp_transport *t, __u32 pmtu) | |
388 | { | |
91bd6b1e | 389 | if (!t || (t->pathmtu <= pmtu)) |
52ccb8e9 FF |
390 | return; |
391 | ||
8a479491 VY |
392 | if (sock_owned_by_user(sk)) { |
393 | asoc->pmtu_pending = 1; | |
394 | t->pmtu_pending = 1; | |
395 | return; | |
396 | } | |
397 | ||
52ccb8e9 | 398 | if (t->param_flags & SPP_PMTUD_ENABLE) { |
c910b47e | 399 | /* Update transports view of the MTU */ |
02f3d4ce | 400 | sctp_transport_update_pmtu(sk, t, pmtu); |
1da177e4 | 401 | |
52ccb8e9 | 402 | /* Update association pmtu. */ |
02f3d4ce | 403 | sctp_assoc_sync_pmtu(sk, asoc); |
1da177e4 | 404 | } |
52ccb8e9 FF |
405 | |
406 | /* Retransmit with the new pmtu setting. | |
407 | * Normally, if PMTU discovery is disabled, an ICMP Fragmentation | |
408 | * Needed will never be sent, but if a message was sent before | |
409 | * PMTU discovery was disabled that was larger than the PMTU, it | |
d808ad9a | 410 | * would not be fragmented, so it must be re-transmitted fragmented. |
52ccb8e9 FF |
411 | */ |
412 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
413 | } |
414 | ||
ec18d9a2 DM |
415 | void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, |
416 | struct sk_buff *skb) | |
55be7a9c DM |
417 | { |
418 | struct dst_entry *dst; | |
419 | ||
420 | if (!t) | |
421 | return; | |
422 | dst = sctp_transport_dst_check(t); | |
1ed5c48f | 423 | if (dst) |
6700c270 | 424 | dst->ops->redirect(dst, sk, skb); |
55be7a9c DM |
425 | } |
426 | ||
1da177e4 LT |
427 | /* |
428 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
429 | * | |
430 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
431 | * or a "Protocol Unreachable" treat this message as an abort | |
432 | * with the T bit set. | |
433 | * | |
434 | * This function sends an event to the state machine, which will abort the | |
435 | * association. | |
436 | * | |
437 | */ | |
438 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
d808ad9a YH |
439 | struct sctp_association *asoc, |
440 | struct sctp_transport *t) | |
1da177e4 | 441 | { |
50b5d6ad VY |
442 | if (sock_owned_by_user(sk)) { |
443 | if (timer_pending(&t->proto_unreach_timer)) | |
444 | return; | |
445 | else { | |
446 | if (!mod_timer(&t->proto_unreach_timer, | |
447 | jiffies + (HZ/20))) | |
448 | sctp_association_hold(asoc); | |
449 | } | |
50b5d6ad | 450 | } else { |
55e26eb9 EB |
451 | struct net *net = sock_net(sk); |
452 | ||
bb33381d DB |
453 | pr_debug("%s: unrecognized next header type " |
454 | "encountered!\n", __func__); | |
455 | ||
25cc4ae9 | 456 | if (del_timer(&t->proto_unreach_timer)) |
50b5d6ad | 457 | sctp_association_put(asoc); |
1da177e4 | 458 | |
55e26eb9 | 459 | sctp_do_sm(net, SCTP_EVENT_T_OTHER, |
50b5d6ad VY |
460 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), |
461 | asoc->state, asoc->ep, asoc, t, | |
462 | GFP_ATOMIC); | |
463 | } | |
1da177e4 LT |
464 | } |
465 | ||
466 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
4110cc25 | 467 | struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb, |
1da177e4 | 468 | struct sctphdr *sctphdr, |
1da177e4 LT |
469 | struct sctp_association **app, |
470 | struct sctp_transport **tpp) | |
471 | { | |
472 | union sctp_addr saddr; | |
473 | union sctp_addr daddr; | |
474 | struct sctp_af *af; | |
475 | struct sock *sk = NULL; | |
8de8c873 | 476 | struct sctp_association *asoc; |
1da177e4 | 477 | struct sctp_transport *transport = NULL; |
7115e632 WY |
478 | struct sctp_init_chunk *chunkhdr; |
479 | __u32 vtag = ntohl(sctphdr->vtag); | |
480 | int len = skb->len - ((void *)sctphdr - (void *)skb->data); | |
1da177e4 | 481 | |
d1ad1ff2 | 482 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
483 | |
484 | af = sctp_get_af_specific(family); | |
485 | if (unlikely(!af)) { | |
486 | return NULL; | |
487 | } | |
488 | ||
489 | /* Initialize local addresses for lookups. */ | |
490 | af->from_skb(&saddr, skb, 1); | |
491 | af->from_skb(&daddr, skb, 0); | |
492 | ||
493 | /* Look for an association that matches the incoming ICMP error | |
494 | * packet. | |
495 | */ | |
4110cc25 | 496 | asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport); |
d1ad1ff2 SS |
497 | if (!asoc) |
498 | return NULL; | |
1da177e4 | 499 | |
d1ad1ff2 | 500 | sk = asoc->base.sk; |
1da177e4 | 501 | |
7115e632 WY |
502 | /* RFC 4960, Appendix C. ICMP Handling |
503 | * | |
504 | * ICMP6) An implementation MUST validate that the Verification Tag | |
505 | * contained in the ICMP message matches the Verification Tag of | |
506 | * the peer. If the Verification Tag is not 0 and does NOT | |
507 | * match, discard the ICMP message. If it is 0 and the ICMP | |
508 | * message contains enough bytes to verify that the chunk type is | |
509 | * an INIT chunk and that the Initiate Tag matches the tag of the | |
510 | * peer, continue with ICMP7. If the ICMP message is too short | |
511 | * or the chunk type or the Initiate Tag does not match, silently | |
512 | * discard the packet. | |
513 | */ | |
514 | if (vtag == 0) { | |
ea110733 | 515 | chunkhdr = (void *)sctphdr + sizeof(struct sctphdr); |
7115e632 WY |
516 | if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t) |
517 | + sizeof(__be32) || | |
518 | chunkhdr->chunk_hdr.type != SCTP_CID_INIT || | |
519 | ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) { | |
520 | goto out; | |
521 | } | |
522 | } else if (vtag != asoc->c.peer_vtag) { | |
d1ad1ff2 SS |
523 | goto out; |
524 | } | |
1da177e4 LT |
525 | |
526 | sctp_bh_lock_sock(sk); | |
527 | ||
528 | /* If too many ICMPs get dropped on busy | |
529 | * servers this needs to be solved differently. | |
530 | */ | |
531 | if (sock_owned_by_user(sk)) | |
b01a2407 | 532 | NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); |
1da177e4 | 533 | |
1da177e4 LT |
534 | *app = asoc; |
535 | *tpp = transport; | |
536 | return sk; | |
537 | ||
538 | out: | |
e4772668 | 539 | sctp_association_put(asoc); |
1da177e4 LT |
540 | return NULL; |
541 | } | |
542 | ||
543 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 544 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
545 | { |
546 | sctp_bh_unlock_sock(sk); | |
e4772668 | 547 | sctp_association_put(asoc); |
1da177e4 LT |
548 | } |
549 | ||
550 | /* | |
551 | * This routine is called by the ICMP module when it gets some | |
552 | * sort of error condition. If err < 0 then the socket should | |
553 | * be closed and the error returned to the user. If err > 0 | |
554 | * it's just the icmp type << 8 | icmp code. After adjustment | |
555 | * header points to the first 8 bytes of the sctp header. We need | |
556 | * to find the appropriate port. | |
557 | * | |
558 | * The locking strategy used here is very "optimistic". When | |
559 | * someone else accesses the socket the ICMP is just dropped | |
560 | * and for some paths there is no check at all. | |
561 | * A more general error queue to queue errors for later handling | |
562 | * is probably better. | |
563 | * | |
564 | */ | |
565 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
566 | { | |
b71d1d42 | 567 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
a27ef749 | 568 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
569 | const int type = icmp_hdr(skb)->type; |
570 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 571 | struct sock *sk; |
8de8c873 | 572 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
573 | struct sctp_transport *transport; |
574 | struct inet_sock *inet; | |
aef6de51 | 575 | __u16 saveip, savesctp; |
1da177e4 | 576 | int err; |
4110cc25 | 577 | struct net *net = dev_net(skb->dev); |
1da177e4 | 578 | |
a27ef749 | 579 | if (skb->len < ihlen + 8) { |
b01a2407 | 580 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
581 | return; |
582 | } | |
583 | ||
584 | /* Fix up skb to look at the embedded net header. */ | |
b0e380b1 ACM |
585 | saveip = skb->network_header; |
586 | savesctp = skb->transport_header; | |
31c7711b | 587 | skb_reset_network_header(skb); |
a27ef749 | 588 | skb_set_transport_header(skb, ihlen); |
4110cc25 | 589 | sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport); |
2e07fa9c | 590 | /* Put back, the original values. */ |
b0e380b1 ACM |
591 | skb->network_header = saveip; |
592 | skb->transport_header = savesctp; | |
1da177e4 | 593 | if (!sk) { |
b01a2407 | 594 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
595 | return; |
596 | } | |
597 | /* Warning: The sock lock is held. Remember to call | |
598 | * sctp_err_finish! | |
599 | */ | |
600 | ||
601 | switch (type) { | |
602 | case ICMP_PARAMETERPROB: | |
603 | err = EPROTO; | |
604 | break; | |
605 | case ICMP_DEST_UNREACH: | |
606 | if (code > NR_ICMP_UNREACH) | |
607 | goto out_unlock; | |
608 | ||
609 | /* PMTU discovery (RFC1191) */ | |
610 | if (ICMP_FRAG_NEEDED == code) { | |
611 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
612 | goto out_unlock; | |
613 | } | |
614 | else { | |
615 | if (ICMP_PROT_UNREACH == code) { | |
d1ad1ff2 | 616 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
617 | transport); |
618 | goto out_unlock; | |
619 | } | |
620 | } | |
621 | err = icmp_err_convert[code].errno; | |
622 | break; | |
623 | case ICMP_TIME_EXCEEDED: | |
624 | /* Ignore any time exceeded errors due to fragment reassembly | |
625 | * timeouts. | |
626 | */ | |
627 | if (ICMP_EXC_FRAGTIME == code) | |
628 | goto out_unlock; | |
629 | ||
630 | err = EHOSTUNREACH; | |
631 | break; | |
55be7a9c DM |
632 | case ICMP_REDIRECT: |
633 | sctp_icmp_redirect(sk, transport, skb); | |
3f96a532 | 634 | /* Fall through to out_unlock. */ |
1da177e4 LT |
635 | default: |
636 | goto out_unlock; | |
637 | } | |
638 | ||
639 | inet = inet_sk(sk); | |
640 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
641 | sk->sk_err = err; | |
642 | sk->sk_error_report(sk); | |
643 | } else { /* Only an error on timeout */ | |
644 | sk->sk_err_soft = err; | |
645 | } | |
646 | ||
647 | out_unlock: | |
d1ad1ff2 | 648 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
649 | } |
650 | ||
651 | /* | |
652 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
653 | * | |
654 | * This function scans all the chunks in the OOTB packet to determine if | |
655 | * the packet should be discarded right away. If a response might be needed | |
656 | * for this packet, or, if further processing is possible, the packet will | |
657 | * be queued to a proper inqueue for the next phase of handling. | |
658 | * | |
659 | * Output: | |
660 | * Return 0 - If further processing is needed. | |
661 | * Return 1 - If the packet can be discarded right away. | |
662 | */ | |
04675210 | 663 | static int sctp_rcv_ootb(struct sk_buff *skb) |
1da177e4 LT |
664 | { |
665 | sctp_chunkhdr_t *ch; | |
666 | __u8 *ch_end; | |
1da177e4 LT |
667 | |
668 | ch = (sctp_chunkhdr_t *) skb->data; | |
1da177e4 LT |
669 | |
670 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 TF |
671 | do { |
672 | /* Break out if chunk length is less then minimal. */ | |
673 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
674 | break; | |
675 | ||
676 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
27a884dc | 677 | if (ch_end > skb_tail_pointer(skb)) |
a7d1f1b6 | 678 | break; |
1da177e4 LT |
679 | |
680 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
681 | * receiver MUST silently discard the OOTB packet and take no | |
682 | * further action. | |
683 | */ | |
684 | if (SCTP_CID_ABORT == ch->type) | |
685 | goto discard; | |
686 | ||
687 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
688 | * chunk, the receiver should silently discard the packet | |
689 | * and take no further action. | |
690 | */ | |
691 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
692 | goto discard; | |
693 | ||
3c77f961 VY |
694 | /* RFC 4460, 2.11.2 |
695 | * This will discard packets with INIT chunk bundled as | |
696 | * subsequent chunks in the packet. When INIT is first, | |
697 | * the normal INIT processing will discard the chunk. | |
698 | */ | |
699 | if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data) | |
700 | goto discard; | |
701 | ||
1da177e4 | 702 | ch = (sctp_chunkhdr_t *) ch_end; |
27a884dc | 703 | } while (ch_end < skb_tail_pointer(skb)); |
1da177e4 LT |
704 | |
705 | return 0; | |
706 | ||
707 | discard: | |
708 | return 1; | |
709 | } | |
710 | ||
711 | /* Insert endpoint into the hash table. */ | |
712 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
713 | { | |
4cdadcbc | 714 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
715 | struct sctp_ep_common *epb; |
716 | struct sctp_hashbucket *head; | |
717 | ||
718 | epb = &ep->base; | |
719 | ||
4cdadcbc | 720 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
721 | head = &sctp_ep_hashtable[epb->hashent]; |
722 | ||
723 | sctp_write_lock(&head->lock); | |
d970dbf8 | 724 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
725 | sctp_write_unlock(&head->lock); |
726 | } | |
727 | ||
728 | /* Add an endpoint to the hash. Local BH-safe. */ | |
729 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
730 | { | |
731 | sctp_local_bh_disable(); | |
732 | __sctp_hash_endpoint(ep); | |
733 | sctp_local_bh_enable(); | |
734 | } | |
735 | ||
736 | /* Remove endpoint from the hash table. */ | |
737 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
738 | { | |
4cdadcbc | 739 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
740 | struct sctp_hashbucket *head; |
741 | struct sctp_ep_common *epb; | |
742 | ||
743 | epb = &ep->base; | |
744 | ||
4cdadcbc | 745 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
746 | |
747 | head = &sctp_ep_hashtable[epb->hashent]; | |
748 | ||
749 | sctp_write_lock(&head->lock); | |
2eebc1e1 | 750 | hlist_del_init(&epb->node); |
1da177e4 LT |
751 | sctp_write_unlock(&head->lock); |
752 | } | |
753 | ||
754 | /* Remove endpoint from the hash. Local BH-safe. */ | |
755 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
756 | { | |
757 | sctp_local_bh_disable(); | |
758 | __sctp_unhash_endpoint(ep); | |
759 | sctp_local_bh_enable(); | |
760 | } | |
761 | ||
762 | /* Look up an endpoint. */ | |
4cdadcbc EB |
763 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net, |
764 | const union sctp_addr *laddr) | |
1da177e4 LT |
765 | { |
766 | struct sctp_hashbucket *head; | |
767 | struct sctp_ep_common *epb; | |
768 | struct sctp_endpoint *ep; | |
769 | int hash; | |
770 | ||
4cdadcbc | 771 | hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
772 | head = &sctp_ep_hashtable[hash]; |
773 | read_lock(&head->lock); | |
b67bfe0d | 774 | sctp_for_each_hentry(epb, &head->chain) { |
1da177e4 | 775 | ep = sctp_ep(epb); |
4cdadcbc | 776 | if (sctp_endpoint_is_match(ep, net, laddr)) |
1da177e4 LT |
777 | goto hit; |
778 | } | |
779 | ||
2ce95503 | 780 | ep = sctp_sk(net->sctp.ctl_sock)->ep; |
1da177e4 LT |
781 | |
782 | hit: | |
783 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
784 | read_unlock(&head->lock); |
785 | return ep; | |
786 | } | |
787 | ||
788 | /* Insert association into the hash table. */ | |
789 | static void __sctp_hash_established(struct sctp_association *asoc) | |
790 | { | |
4110cc25 | 791 | struct net *net = sock_net(asoc->base.sk); |
1da177e4 LT |
792 | struct sctp_ep_common *epb; |
793 | struct sctp_hashbucket *head; | |
794 | ||
795 | epb = &asoc->base; | |
796 | ||
797 | /* Calculate which chain this entry will belong to. */ | |
4110cc25 EB |
798 | epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port, |
799 | asoc->peer.port); | |
1da177e4 LT |
800 | |
801 | head = &sctp_assoc_hashtable[epb->hashent]; | |
802 | ||
803 | sctp_write_lock(&head->lock); | |
d970dbf8 | 804 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
805 | sctp_write_unlock(&head->lock); |
806 | } | |
807 | ||
808 | /* Add an association to the hash. Local BH-safe. */ | |
809 | void sctp_hash_established(struct sctp_association *asoc) | |
810 | { | |
de76e695 VY |
811 | if (asoc->temp) |
812 | return; | |
813 | ||
1da177e4 LT |
814 | sctp_local_bh_disable(); |
815 | __sctp_hash_established(asoc); | |
816 | sctp_local_bh_enable(); | |
817 | } | |
818 | ||
819 | /* Remove association from the hash table. */ | |
820 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
821 | { | |
4110cc25 | 822 | struct net *net = sock_net(asoc->base.sk); |
1da177e4 LT |
823 | struct sctp_hashbucket *head; |
824 | struct sctp_ep_common *epb; | |
825 | ||
826 | epb = &asoc->base; | |
827 | ||
4110cc25 | 828 | epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port, |
1da177e4 LT |
829 | asoc->peer.port); |
830 | ||
831 | head = &sctp_assoc_hashtable[epb->hashent]; | |
832 | ||
833 | sctp_write_lock(&head->lock); | |
2eebc1e1 | 834 | hlist_del_init(&epb->node); |
1da177e4 LT |
835 | sctp_write_unlock(&head->lock); |
836 | } | |
837 | ||
838 | /* Remove association from the hash table. Local BH-safe. */ | |
839 | void sctp_unhash_established(struct sctp_association *asoc) | |
840 | { | |
de76e695 VY |
841 | if (asoc->temp) |
842 | return; | |
843 | ||
1da177e4 LT |
844 | sctp_local_bh_disable(); |
845 | __sctp_unhash_established(asoc); | |
846 | sctp_local_bh_enable(); | |
847 | } | |
848 | ||
849 | /* Look up an association. */ | |
850 | static struct sctp_association *__sctp_lookup_association( | |
4110cc25 | 851 | struct net *net, |
1da177e4 LT |
852 | const union sctp_addr *local, |
853 | const union sctp_addr *peer, | |
854 | struct sctp_transport **pt) | |
855 | { | |
856 | struct sctp_hashbucket *head; | |
857 | struct sctp_ep_common *epb; | |
858 | struct sctp_association *asoc; | |
859 | struct sctp_transport *transport; | |
860 | int hash; | |
861 | ||
862 | /* Optimize here for direct hit, only listening connections can | |
863 | * have wildcards anyways. | |
864 | */ | |
4110cc25 EB |
865 | hash = sctp_assoc_hashfn(net, ntohs(local->v4.sin_port), |
866 | ntohs(peer->v4.sin_port)); | |
1da177e4 LT |
867 | head = &sctp_assoc_hashtable[hash]; |
868 | read_lock(&head->lock); | |
b67bfe0d | 869 | sctp_for_each_hentry(epb, &head->chain) { |
1da177e4 | 870 | asoc = sctp_assoc(epb); |
4110cc25 | 871 | transport = sctp_assoc_is_match(asoc, net, local, peer); |
1da177e4 LT |
872 | if (transport) |
873 | goto hit; | |
874 | } | |
875 | ||
876 | read_unlock(&head->lock); | |
877 | ||
878 | return NULL; | |
879 | ||
880 | hit: | |
881 | *pt = transport; | |
882 | sctp_association_hold(asoc); | |
1da177e4 LT |
883 | read_unlock(&head->lock); |
884 | return asoc; | |
885 | } | |
886 | ||
887 | /* Look up an association. BH-safe. */ | |
dda91928 | 888 | static |
4110cc25 EB |
889 | struct sctp_association *sctp_lookup_association(struct net *net, |
890 | const union sctp_addr *laddr, | |
1da177e4 | 891 | const union sctp_addr *paddr, |
dda91928 | 892 | struct sctp_transport **transportp) |
1da177e4 LT |
893 | { |
894 | struct sctp_association *asoc; | |
895 | ||
896 | sctp_local_bh_disable(); | |
4110cc25 | 897 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
1da177e4 LT |
898 | sctp_local_bh_enable(); |
899 | ||
900 | return asoc; | |
901 | } | |
902 | ||
903 | /* Is there an association matching the given local and peer addresses? */ | |
4110cc25 EB |
904 | int sctp_has_association(struct net *net, |
905 | const union sctp_addr *laddr, | |
1da177e4 LT |
906 | const union sctp_addr *paddr) |
907 | { | |
908 | struct sctp_association *asoc; | |
909 | struct sctp_transport *transport; | |
910 | ||
4110cc25 | 911 | if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) { |
1da177e4 LT |
912 | sctp_association_put(asoc); |
913 | return 1; | |
914 | } | |
915 | ||
916 | return 0; | |
917 | } | |
918 | ||
919 | /* | |
920 | * SCTP Implementors Guide, 2.18 Handling of address | |
921 | * parameters within the INIT or INIT-ACK. | |
922 | * | |
923 | * D) When searching for a matching TCB upon reception of an INIT | |
924 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
925 | * source address of the packet (containing the INIT or | |
926 | * INIT-ACK) but the receiver SHOULD also use all valid | |
927 | * address parameters contained within the chunk. | |
928 | * | |
929 | * 2.18.3 Solution description | |
930 | * | |
931 | * This new text clearly specifies to an implementor the need | |
932 | * to look within the INIT or INIT-ACK. Any implementation that | |
933 | * does not do this, may not be able to establish associations | |
934 | * in certain circumstances. | |
935 | * | |
936 | */ | |
4110cc25 EB |
937 | static struct sctp_association *__sctp_rcv_init_lookup(struct net *net, |
938 | struct sk_buff *skb, | |
1da177e4 LT |
939 | const union sctp_addr *laddr, struct sctp_transport **transportp) |
940 | { | |
941 | struct sctp_association *asoc; | |
942 | union sctp_addr addr; | |
943 | union sctp_addr *paddr = &addr; | |
2c0fd387 | 944 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
945 | union sctp_params params; |
946 | sctp_init_chunk_t *init; | |
947 | struct sctp_transport *transport; | |
948 | struct sctp_af *af; | |
949 | ||
1da177e4 LT |
950 | /* |
951 | * This code will NOT touch anything inside the chunk--it is | |
952 | * strictly READ-ONLY. | |
953 | * | |
954 | * RFC 2960 3 SCTP packet Format | |
955 | * | |
956 | * Multiple chunks can be bundled into one SCTP packet up to | |
957 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
958 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
959 | * other chunk in a packet. See Section 6.10 for more details | |
960 | * on chunk bundling. | |
961 | */ | |
962 | ||
963 | /* Find the start of the TLVs and the end of the chunk. This is | |
964 | * the region we search for address parameters. | |
965 | */ | |
966 | init = (sctp_init_chunk_t *)skb->data; | |
967 | ||
968 | /* Walk the parameters looking for embedded addresses. */ | |
969 | sctp_walk_params(params, init, init_hdr.params) { | |
970 | ||
971 | /* Note: Ignoring hostname addresses. */ | |
972 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
973 | if (!af) | |
974 | continue; | |
975 | ||
dd86d136 | 976 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 977 | |
4110cc25 | 978 | asoc = __sctp_lookup_association(net, laddr, paddr, &transport); |
1da177e4 LT |
979 | if (asoc) |
980 | return asoc; | |
981 | } | |
982 | ||
983 | return NULL; | |
984 | } | |
985 | ||
df218577 VY |
986 | /* ADD-IP, Section 5.2 |
987 | * When an endpoint receives an ASCONF Chunk from the remote peer | |
988 | * special procedures may be needed to identify the association the | |
989 | * ASCONF Chunk is associated with. To properly find the association | |
990 | * the following procedures SHOULD be followed: | |
991 | * | |
992 | * D2) If the association is not found, use the address found in the | |
993 | * Address Parameter TLV combined with the port number found in the | |
994 | * SCTP common header. If found proceed to rule D4. | |
995 | * | |
996 | * D2-ext) If more than one ASCONF Chunks are packed together, use the | |
997 | * address found in the ASCONF Address Parameter TLV of each of the | |
998 | * subsequent ASCONF Chunks. If found, proceed to rule D4. | |
999 | */ | |
1000 | static struct sctp_association *__sctp_rcv_asconf_lookup( | |
4110cc25 | 1001 | struct net *net, |
df218577 VY |
1002 | sctp_chunkhdr_t *ch, |
1003 | const union sctp_addr *laddr, | |
bc92dd19 | 1004 | __be16 peer_port, |
df218577 VY |
1005 | struct sctp_transport **transportp) |
1006 | { | |
1007 | sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch; | |
1008 | struct sctp_af *af; | |
1009 | union sctp_addr_param *param; | |
1010 | union sctp_addr paddr; | |
1011 | ||
1012 | /* Skip over the ADDIP header and find the Address parameter */ | |
1013 | param = (union sctp_addr_param *)(asconf + 1); | |
1014 | ||
6a435732 | 1015 | af = sctp_get_af_specific(param_type2af(param->p.type)); |
df218577 VY |
1016 | if (unlikely(!af)) |
1017 | return NULL; | |
1018 | ||
1019 | af->from_addr_param(&paddr, param, peer_port, 0); | |
1020 | ||
4110cc25 | 1021 | return __sctp_lookup_association(net, laddr, &paddr, transportp); |
df218577 VY |
1022 | } |
1023 | ||
1024 | ||
bbd0d598 VY |
1025 | /* SCTP-AUTH, Section 6.3: |
1026 | * If the receiver does not find a STCB for a packet containing an AUTH | |
1027 | * chunk as the first chunk and not a COOKIE-ECHO chunk as the second | |
1028 | * chunk, it MUST use the chunks after the AUTH chunk to look up an existing | |
1029 | * association. | |
1030 | * | |
1031 | * This means that any chunks that can help us identify the association need | |
25985edc | 1032 | * to be looked at to find this association. |
bbd0d598 | 1033 | */ |
4110cc25 EB |
1034 | static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net, |
1035 | struct sk_buff *skb, | |
bbd0d598 VY |
1036 | const union sctp_addr *laddr, |
1037 | struct sctp_transport **transportp) | |
1038 | { | |
df218577 VY |
1039 | struct sctp_association *asoc = NULL; |
1040 | sctp_chunkhdr_t *ch; | |
1041 | int have_auth = 0; | |
1042 | unsigned int chunk_num = 1; | |
1043 | __u8 *ch_end; | |
1044 | ||
1045 | /* Walk through the chunks looking for AUTH or ASCONF chunks | |
1046 | * to help us find the association. | |
bbd0d598 | 1047 | */ |
df218577 VY |
1048 | ch = (sctp_chunkhdr_t *) skb->data; |
1049 | do { | |
1050 | /* Break out if chunk length is less then minimal. */ | |
1051 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
1052 | break; | |
1053 | ||
1054 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
1055 | if (ch_end > skb_tail_pointer(skb)) | |
1056 | break; | |
1057 | ||
cb3f837b | 1058 | switch (ch->type) { |
df218577 VY |
1059 | case SCTP_CID_AUTH: |
1060 | have_auth = chunk_num; | |
1061 | break; | |
1062 | ||
1063 | case SCTP_CID_COOKIE_ECHO: | |
1064 | /* If a packet arrives containing an AUTH chunk as | |
1065 | * a first chunk, a COOKIE-ECHO chunk as the second | |
1066 | * chunk, and possibly more chunks after them, and | |
1067 | * the receiver does not have an STCB for that | |
1068 | * packet, then authentication is based on | |
1069 | * the contents of the COOKIE- ECHO chunk. | |
1070 | */ | |
1071 | if (have_auth == 1 && chunk_num == 2) | |
1072 | return NULL; | |
1073 | break; | |
1074 | ||
1075 | case SCTP_CID_ASCONF: | |
e1fc3b14 | 1076 | if (have_auth || net->sctp.addip_noauth) |
4110cc25 EB |
1077 | asoc = __sctp_rcv_asconf_lookup( |
1078 | net, ch, laddr, | |
df218577 VY |
1079 | sctp_hdr(skb)->source, |
1080 | transportp); | |
1081 | default: | |
1082 | break; | |
1083 | } | |
1084 | ||
1085 | if (asoc) | |
1086 | break; | |
1087 | ||
1088 | ch = (sctp_chunkhdr_t *) ch_end; | |
1089 | chunk_num++; | |
1090 | } while (ch_end < skb_tail_pointer(skb)); | |
1091 | ||
1092 | return asoc; | |
bbd0d598 VY |
1093 | } |
1094 | ||
1095 | /* | |
1096 | * There are circumstances when we need to look inside the SCTP packet | |
1097 | * for information to help us find the association. Examples | |
1098 | * include looking inside of INIT/INIT-ACK chunks or after the AUTH | |
1099 | * chunks. | |
1100 | */ | |
4110cc25 EB |
1101 | static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net, |
1102 | struct sk_buff *skb, | |
bbd0d598 VY |
1103 | const union sctp_addr *laddr, |
1104 | struct sctp_transport **transportp) | |
1105 | { | |
1106 | sctp_chunkhdr_t *ch; | |
1107 | ||
1108 | ch = (sctp_chunkhdr_t *) skb->data; | |
1109 | ||
df218577 VY |
1110 | /* The code below will attempt to walk the chunk and extract |
1111 | * parameter information. Before we do that, we need to verify | |
1112 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
1113 | * walk off the end. | |
1114 | */ | |
1115 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
1116 | return NULL; | |
1117 | ||
bbd0d598 | 1118 | /* If this is INIT/INIT-ACK look inside the chunk too. */ |
f482f2fc | 1119 | if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK) |
4110cc25 | 1120 | return __sctp_rcv_init_lookup(net, skb, laddr, transportp); |
bbd0d598 | 1121 | |
f482f2fc | 1122 | return __sctp_rcv_walk_lookup(net, skb, laddr, transportp); |
bbd0d598 VY |
1123 | } |
1124 | ||
1da177e4 | 1125 | /* Lookup an association for an inbound skb. */ |
4110cc25 EB |
1126 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
1127 | struct sk_buff *skb, | |
1da177e4 LT |
1128 | const union sctp_addr *paddr, |
1129 | const union sctp_addr *laddr, | |
1130 | struct sctp_transport **transportp) | |
1131 | { | |
1132 | struct sctp_association *asoc; | |
1133 | ||
4110cc25 | 1134 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
1da177e4 LT |
1135 | |
1136 | /* Further lookup for INIT/INIT-ACK packets. | |
1137 | * SCTP Implementors Guide, 2.18 Handling of address | |
1138 | * parameters within the INIT or INIT-ACK. | |
1139 | */ | |
1140 | if (!asoc) | |
4110cc25 | 1141 | asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp); |
1da177e4 LT |
1142 | |
1143 | return asoc; | |
1144 | } |