]>
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 | |
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): | |
91705c61 | 32 | * lksctp developers <linux-sctp@vger.kernel.org> |
1da177e4 | 33 | * |
1da177e4 LT |
34 | * Written or modified by: |
35 | * La Monte H.P. Yarroll <piggy@acm.org> | |
36 | * Karl Knutson <karl@athena.chicago.il.us> | |
37 | * Xingang Guo <xingang.guo@intel.com> | |
38 | * Jon Grimm <jgrimm@us.ibm.com> | |
39 | * Hui Huang <hui.huang@nokia.com> | |
40 | * Daisy Chang <daisyc@us.ibm.com> | |
41 | * Sridhar Samudrala <sri@us.ibm.com> | |
42 | * Ardelle Fan <ardelle.fan@intel.com> | |
1da177e4 LT |
43 | */ |
44 | ||
45 | #include <linux/types.h> | |
46 | #include <linux/list.h> /* For struct list_head */ | |
47 | #include <linux/socket.h> | |
48 | #include <linux/ip.h> | |
49 | #include <linux/time.h> /* For struct timeval */ | |
5a0e3ad6 | 50 | #include <linux/slab.h> |
1da177e4 LT |
51 | #include <net/ip.h> |
52 | #include <net/icmp.h> | |
53 | #include <net/snmp.h> | |
54 | #include <net/sock.h> | |
55 | #include <net/xfrm.h> | |
56 | #include <net/sctp/sctp.h> | |
57 | #include <net/sctp/sm.h> | |
9ad0977f | 58 | #include <net/sctp/checksum.h> |
dcfc23ca | 59 | #include <net/net_namespace.h> |
1da177e4 LT |
60 | |
61 | /* Forward declarations for internal helpers. */ | |
62 | static int sctp_rcv_ootb(struct sk_buff *); | |
4110cc25 EB |
63 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
64 | struct sk_buff *skb, | |
1da177e4 | 65 | const union sctp_addr *paddr, |
57565993 | 66 | const union sctp_addr *laddr, |
1da177e4 | 67 | struct sctp_transport **transportp); |
4cdadcbc EB |
68 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net, |
69 | const union sctp_addr *laddr); | |
1da177e4 | 70 | static struct sctp_association *__sctp_lookup_association( |
4110cc25 | 71 | struct net *net, |
1da177e4 LT |
72 | const union sctp_addr *local, |
73 | const union sctp_addr *peer, | |
74 | struct sctp_transport **pt); | |
75 | ||
50b1a782 | 76 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb); |
61c9fed4 | 77 | |
1da177e4 LT |
78 | |
79 | /* Calculate the SCTP checksum of an SCTP packet. */ | |
b01a2407 | 80 | static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb) |
1da177e4 | 81 | { |
2c0fd387 | 82 | struct sctphdr *sh = sctp_hdr(skb); |
4458f04c | 83 | __le32 cmp = sh->checksum; |
024ec3de | 84 | __le32 val = sctp_compute_cksum(skb, 0); |
1da177e4 LT |
85 | |
86 | if (val != cmp) { | |
87 | /* CRC failure, dump it. */ | |
b01a2407 | 88 | SCTP_INC_STATS_BH(net, SCTP_MIB_CHECKSUMERRORS); |
1da177e4 LT |
89 | return -1; |
90 | } | |
91 | return 0; | |
92 | } | |
93 | ||
79af02c2 DM |
94 | struct sctp_input_cb { |
95 | union { | |
96 | struct inet_skb_parm h4; | |
dfd56b8b | 97 | #if IS_ENABLED(CONFIG_IPV6) |
79af02c2 DM |
98 | struct inet6_skb_parm h6; |
99 | #endif | |
100 | } header; | |
101 | struct sctp_chunk *chunk; | |
102 | }; | |
103 | #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) | |
104 | ||
1da177e4 LT |
105 | /* |
106 | * This is the routine which IP calls when receiving an SCTP packet. | |
107 | */ | |
108 | int sctp_rcv(struct sk_buff *skb) | |
109 | { | |
110 | struct sock *sk; | |
111 | struct sctp_association *asoc; | |
112 | struct sctp_endpoint *ep = NULL; | |
113 | struct sctp_ep_common *rcvr; | |
114 | struct sctp_transport *transport = NULL; | |
115 | struct sctp_chunk *chunk; | |
116 | struct sctphdr *sh; | |
117 | union sctp_addr src; | |
118 | union sctp_addr dest; | |
119 | int family; | |
120 | struct sctp_af *af; | |
4cdadcbc | 121 | struct net *net = dev_net(skb->dev); |
1da177e4 LT |
122 | |
123 | if (skb->pkt_type!=PACKET_HOST) | |
124 | goto discard_it; | |
125 | ||
b01a2407 | 126 | SCTP_INC_STATS_BH(net, SCTP_MIB_INSCTPPACKS); |
1da177e4 | 127 | |
28cd7752 HX |
128 | if (skb_linearize(skb)) |
129 | goto discard_it; | |
130 | ||
2c0fd387 | 131 | sh = sctp_hdr(skb); |
1da177e4 LT |
132 | |
133 | /* Pull up the IP and SCTP headers. */ | |
ea2ae17d | 134 | __skb_pull(skb, skb_transport_offset(skb)); |
1da177e4 LT |
135 | if (skb->len < sizeof(struct sctphdr)) |
136 | goto discard_it; | |
71acc0dd DM |
137 | if (!sctp_checksum_disable && !skb_csum_unnecessary(skb) && |
138 | sctp_rcv_checksum(net, skb) < 0) | |
1da177e4 LT |
139 | goto discard_it; |
140 | ||
141 | skb_pull(skb, sizeof(struct sctphdr)); | |
142 | ||
143 | /* Make sure we at least have chunk headers worth of data left. */ | |
144 | if (skb->len < sizeof(struct sctp_chunkhdr)) | |
145 | goto discard_it; | |
146 | ||
eddc9ec5 | 147 | family = ipver2af(ip_hdr(skb)->version); |
1da177e4 LT |
148 | af = sctp_get_af_specific(family); |
149 | if (unlikely(!af)) | |
150 | goto discard_it; | |
151 | ||
152 | /* Initialize local addresses for lookups. */ | |
153 | af->from_skb(&src, skb, 1); | |
154 | af->from_skb(&dest, skb, 0); | |
155 | ||
156 | /* If the packet is to or from a non-unicast address, | |
157 | * silently discard the packet. | |
158 | * | |
159 | * This is not clearly defined in the RFC except in section | |
160 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
161 | * Transmission Protocol" 2.1, "It is important to note that the | |
162 | * IP address of an SCTP transport address must be a routable | |
163 | * unicast address. In other words, IP multicast addresses and | |
164 | * IP broadcast addresses cannot be used in an SCTP transport | |
165 | * address." | |
166 | */ | |
5636bef7 VY |
167 | if (!af->addr_valid(&src, NULL, skb) || |
168 | !af->addr_valid(&dest, NULL, skb)) | |
1da177e4 LT |
169 | goto discard_it; |
170 | ||
4110cc25 | 171 | asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport); |
1c7d1fc1 | 172 | |
0fd9a65a | 173 | if (!asoc) |
4cdadcbc | 174 | ep = __sctp_rcv_lookup_endpoint(net, &dest); |
0fd9a65a NH |
175 | |
176 | /* Retrieve the common input handling substructure. */ | |
177 | rcvr = asoc ? &asoc->base : &ep->base; | |
178 | sk = rcvr->sk; | |
179 | ||
180 | /* | |
181 | * If a frame arrives on an interface and the receiving socket is | |
182 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
183 | */ | |
184 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) | |
185 | { | |
0fd9a65a NH |
186 | if (asoc) { |
187 | sctp_association_put(asoc); | |
188 | asoc = NULL; | |
189 | } else { | |
190 | sctp_endpoint_put(ep); | |
191 | ep = NULL; | |
192 | } | |
2ce95503 | 193 | sk = net->sctp.ctl_sock; |
0fd9a65a NH |
194 | ep = sctp_sk(sk)->ep; |
195 | sctp_endpoint_hold(ep); | |
0fd9a65a NH |
196 | rcvr = &ep->base; |
197 | } | |
198 | ||
1da177e4 LT |
199 | /* |
200 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
201 | * An SCTP packet is called an "out of the blue" (OOTB) | |
202 | * packet if it is correctly formed, i.e., passed the | |
203 | * receiver's checksum check, but the receiver is not | |
204 | * able to identify the association to which this | |
205 | * packet belongs. | |
206 | */ | |
207 | if (!asoc) { | |
1da177e4 | 208 | if (sctp_rcv_ootb(skb)) { |
b01a2407 | 209 | SCTP_INC_STATS_BH(net, SCTP_MIB_OUTOFBLUES); |
1da177e4 LT |
210 | goto discard_release; |
211 | } | |
212 | } | |
213 | ||
1da177e4 LT |
214 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
215 | goto discard_release; | |
b59c2701 | 216 | nf_reset(skb); |
1da177e4 | 217 | |
fda9ef5d | 218 | if (sk_filter(sk, skb)) |
d808ad9a | 219 | goto discard_release; |
1da177e4 LT |
220 | |
221 | /* Create an SCTP packet structure. */ | |
222 | chunk = sctp_chunkify(skb, asoc, sk); | |
2babf9da | 223 | if (!chunk) |
1da177e4 | 224 | goto discard_release; |
79af02c2 | 225 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 226 | |
1da177e4 LT |
227 | /* Remember what endpoint is to handle this packet. */ |
228 | chunk->rcvr = rcvr; | |
229 | ||
230 | /* Remember the SCTP header. */ | |
231 | chunk->sctp_hdr = sh; | |
232 | ||
233 | /* Set the source and destination addresses of the incoming chunk. */ | |
d55c41b1 | 234 | sctp_init_addrs(chunk, &src, &dest); |
1da177e4 LT |
235 | |
236 | /* Remember where we came from. */ | |
237 | chunk->transport = transport; | |
238 | ||
239 | /* Acquire access to the sock lock. Note: We are safe from other | |
240 | * bottom halves on this lock, but a user may be in the lock too, | |
241 | * so check if it is busy. | |
242 | */ | |
243 | sctp_bh_lock_sock(sk); | |
244 | ||
ae53b5bd VY |
245 | if (sk != rcvr->sk) { |
246 | /* Our cached sk is different from the rcvr->sk. This is | |
247 | * because migrate()/accept() may have moved the association | |
248 | * to a new socket and released all the sockets. So now we | |
249 | * are holding a lock on the old socket while the user may | |
250 | * be doing something with the new socket. Switch our veiw | |
251 | * of the current sk. | |
252 | */ | |
253 | sctp_bh_unlock_sock(sk); | |
254 | sk = rcvr->sk; | |
255 | sctp_bh_lock_sock(sk); | |
256 | } | |
257 | ||
ac0b0462 | 258 | if (sock_owned_by_user(sk)) { |
50b1a782 ZY |
259 | if (sctp_add_backlog(sk, skb)) { |
260 | sctp_bh_unlock_sock(sk); | |
261 | sctp_chunk_free(chunk); | |
262 | skb = NULL; /* sctp_chunk_free already freed the skb */ | |
263 | goto discard_release; | |
264 | } | |
b01a2407 | 265 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_BACKLOG); |
ac0b0462 | 266 | } else { |
b01a2407 | 267 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_SOFTIRQ); |
61c9fed4 | 268 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 269 | } |
1da177e4 | 270 | |
1da177e4 | 271 | sctp_bh_unlock_sock(sk); |
61c9fed4 VY |
272 | |
273 | /* Release the asoc/ep ref we took in the lookup calls. */ | |
274 | if (asoc) | |
275 | sctp_association_put(asoc); | |
276 | else | |
277 | sctp_endpoint_put(ep); | |
7a48f923 | 278 | |
2babf9da | 279 | return 0; |
1da177e4 LT |
280 | |
281 | discard_it: | |
b01a2407 | 282 | SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_DISCARDS); |
1da177e4 | 283 | kfree_skb(skb); |
2babf9da | 284 | return 0; |
1da177e4 LT |
285 | |
286 | discard_release: | |
61c9fed4 | 287 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 288 | if (asoc) |
1da177e4 | 289 | sctp_association_put(asoc); |
0fd9a65a | 290 | else |
1da177e4 | 291 | sctp_endpoint_put(ep); |
1da177e4 LT |
292 | |
293 | goto discard_it; | |
294 | } | |
295 | ||
61c9fed4 VY |
296 | /* Process the backlog queue of the socket. Every skb on |
297 | * the backlog holds a ref on an association or endpoint. | |
298 | * We hold this ref throughout the state machine to make | |
299 | * sure that the structure we need is still around. | |
1da177e4 LT |
300 | */ |
301 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
302 | { | |
79af02c2 | 303 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
d808ad9a YH |
304 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
305 | struct sctp_ep_common *rcvr = NULL; | |
61c9fed4 | 306 | int backloged = 0; |
7a48f923 | 307 | |
d808ad9a | 308 | rcvr = chunk->rcvr; |
c4d2444e | 309 | |
61c9fed4 VY |
310 | /* If the rcvr is dead then the association or endpoint |
311 | * has been deleted and we can safely drop the chunk | |
312 | * and refs that we are holding. | |
313 | */ | |
314 | if (rcvr->dead) { | |
315 | sctp_chunk_free(chunk); | |
316 | goto done; | |
317 | } | |
318 | ||
319 | if (unlikely(rcvr->sk != sk)) { | |
320 | /* In this case, the association moved from one socket to | |
321 | * another. We are currently sitting on the backlog of the | |
322 | * old socket, so we need to move. | |
323 | * However, since we are here in the process context we | |
324 | * need to take make sure that the user doesn't own | |
325 | * the new socket when we process the packet. | |
326 | * If the new socket is user-owned, queue the chunk to the | |
327 | * backlog of the new socket without dropping any refs. | |
328 | * Otherwise, we can safely push the chunk on the inqueue. | |
329 | */ | |
330 | ||
331 | sk = rcvr->sk; | |
332 | sctp_bh_lock_sock(sk); | |
333 | ||
334 | if (sock_owned_by_user(sk)) { | |
f545a38f | 335 | if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) |
50b1a782 ZY |
336 | sctp_chunk_free(chunk); |
337 | else | |
338 | backloged = 1; | |
61c9fed4 VY |
339 | } else |
340 | sctp_inq_push(inqueue, chunk); | |
341 | ||
342 | sctp_bh_unlock_sock(sk); | |
343 | ||
344 | /* If the chunk was backloged again, don't drop refs */ | |
345 | if (backloged) | |
346 | return 0; | |
347 | } else { | |
348 | sctp_inq_push(inqueue, chunk); | |
349 | } | |
350 | ||
351 | done: | |
352 | /* Release the refs we took in sctp_add_backlog */ | |
353 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
354 | sctp_association_put(sctp_assoc(rcvr)); | |
355 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
356 | sctp_endpoint_put(sctp_ep(rcvr)); | |
357 | else | |
358 | BUG(); | |
359 | ||
d808ad9a | 360 | return 0; |
1da177e4 LT |
361 | } |
362 | ||
50b1a782 | 363 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 364 | { |
61c9fed4 VY |
365 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
366 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
50b1a782 | 367 | int ret; |
c4d2444e | 368 | |
f545a38f | 369 | ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf); |
50b1a782 ZY |
370 | if (!ret) { |
371 | /* Hold the assoc/ep while hanging on the backlog queue. | |
372 | * This way, we know structures we need will not disappear | |
373 | * from us | |
374 | */ | |
375 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
376 | sctp_association_hold(sctp_assoc(rcvr)); | |
377 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
378 | sctp_endpoint_hold(sctp_ep(rcvr)); | |
379 | else | |
380 | BUG(); | |
381 | } | |
382 | return ret; | |
61c9fed4 | 383 | |
c4d2444e SS |
384 | } |
385 | ||
1da177e4 LT |
386 | /* Handle icmp frag needed error. */ |
387 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
388 | struct sctp_transport *t, __u32 pmtu) | |
389 | { | |
91bd6b1e | 390 | if (!t || (t->pathmtu <= pmtu)) |
52ccb8e9 FF |
391 | return; |
392 | ||
8a479491 VY |
393 | if (sock_owned_by_user(sk)) { |
394 | asoc->pmtu_pending = 1; | |
395 | t->pmtu_pending = 1; | |
396 | return; | |
397 | } | |
398 | ||
52ccb8e9 | 399 | if (t->param_flags & SPP_PMTUD_ENABLE) { |
c910b47e | 400 | /* Update transports view of the MTU */ |
02f3d4ce | 401 | sctp_transport_update_pmtu(sk, t, pmtu); |
1da177e4 | 402 | |
52ccb8e9 | 403 | /* Update association pmtu. */ |
02f3d4ce | 404 | sctp_assoc_sync_pmtu(sk, asoc); |
1da177e4 | 405 | } |
52ccb8e9 FF |
406 | |
407 | /* Retransmit with the new pmtu setting. | |
408 | * Normally, if PMTU discovery is disabled, an ICMP Fragmentation | |
409 | * Needed will never be sent, but if a message was sent before | |
410 | * PMTU discovery was disabled that was larger than the PMTU, it | |
d808ad9a | 411 | * would not be fragmented, so it must be re-transmitted fragmented. |
52ccb8e9 FF |
412 | */ |
413 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
414 | } |
415 | ||
ec18d9a2 DM |
416 | void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, |
417 | struct sk_buff *skb) | |
55be7a9c DM |
418 | { |
419 | struct dst_entry *dst; | |
420 | ||
421 | if (!t) | |
422 | return; | |
423 | dst = sctp_transport_dst_check(t); | |
1ed5c48f | 424 | if (dst) |
6700c270 | 425 | dst->ops->redirect(dst, sk, skb); |
55be7a9c DM |
426 | } |
427 | ||
1da177e4 LT |
428 | /* |
429 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
430 | * | |
431 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
432 | * or a "Protocol Unreachable" treat this message as an abort | |
433 | * with the T bit set. | |
434 | * | |
435 | * This function sends an event to the state machine, which will abort the | |
436 | * association. | |
437 | * | |
438 | */ | |
439 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
d808ad9a YH |
440 | struct sctp_association *asoc, |
441 | struct sctp_transport *t) | |
1da177e4 | 442 | { |
50b5d6ad VY |
443 | if (sock_owned_by_user(sk)) { |
444 | if (timer_pending(&t->proto_unreach_timer)) | |
445 | return; | |
446 | else { | |
447 | if (!mod_timer(&t->proto_unreach_timer, | |
448 | jiffies + (HZ/20))) | |
449 | sctp_association_hold(asoc); | |
450 | } | |
50b5d6ad | 451 | } else { |
55e26eb9 EB |
452 | struct net *net = sock_net(sk); |
453 | ||
bb33381d DB |
454 | pr_debug("%s: unrecognized next header type " |
455 | "encountered!\n", __func__); | |
456 | ||
25cc4ae9 | 457 | if (del_timer(&t->proto_unreach_timer)) |
50b5d6ad | 458 | sctp_association_put(asoc); |
1da177e4 | 459 | |
55e26eb9 | 460 | sctp_do_sm(net, SCTP_EVENT_T_OTHER, |
50b5d6ad VY |
461 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), |
462 | asoc->state, asoc->ep, asoc, t, | |
463 | GFP_ATOMIC); | |
464 | } | |
1da177e4 LT |
465 | } |
466 | ||
467 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
4110cc25 | 468 | struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb, |
1da177e4 | 469 | struct sctphdr *sctphdr, |
1da177e4 LT |
470 | struct sctp_association **app, |
471 | struct sctp_transport **tpp) | |
472 | { | |
473 | union sctp_addr saddr; | |
474 | union sctp_addr daddr; | |
475 | struct sctp_af *af; | |
476 | struct sock *sk = NULL; | |
8de8c873 | 477 | struct sctp_association *asoc; |
1da177e4 | 478 | struct sctp_transport *transport = NULL; |
7115e632 WY |
479 | struct sctp_init_chunk *chunkhdr; |
480 | __u32 vtag = ntohl(sctphdr->vtag); | |
481 | int len = skb->len - ((void *)sctphdr - (void *)skb->data); | |
1da177e4 | 482 | |
d1ad1ff2 | 483 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
484 | |
485 | af = sctp_get_af_specific(family); | |
486 | if (unlikely(!af)) { | |
487 | return NULL; | |
488 | } | |
489 | ||
490 | /* Initialize local addresses for lookups. */ | |
491 | af->from_skb(&saddr, skb, 1); | |
492 | af->from_skb(&daddr, skb, 0); | |
493 | ||
494 | /* Look for an association that matches the incoming ICMP error | |
495 | * packet. | |
496 | */ | |
4110cc25 | 497 | asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport); |
d1ad1ff2 SS |
498 | if (!asoc) |
499 | return NULL; | |
1da177e4 | 500 | |
d1ad1ff2 | 501 | sk = asoc->base.sk; |
1da177e4 | 502 | |
7115e632 WY |
503 | /* RFC 4960, Appendix C. ICMP Handling |
504 | * | |
505 | * ICMP6) An implementation MUST validate that the Verification Tag | |
506 | * contained in the ICMP message matches the Verification Tag of | |
507 | * the peer. If the Verification Tag is not 0 and does NOT | |
508 | * match, discard the ICMP message. If it is 0 and the ICMP | |
509 | * message contains enough bytes to verify that the chunk type is | |
510 | * an INIT chunk and that the Initiate Tag matches the tag of the | |
511 | * peer, continue with ICMP7. If the ICMP message is too short | |
512 | * or the chunk type or the Initiate Tag does not match, silently | |
513 | * discard the packet. | |
514 | */ | |
515 | if (vtag == 0) { | |
ea110733 | 516 | chunkhdr = (void *)sctphdr + sizeof(struct sctphdr); |
7115e632 WY |
517 | if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t) |
518 | + sizeof(__be32) || | |
519 | chunkhdr->chunk_hdr.type != SCTP_CID_INIT || | |
520 | ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) { | |
521 | goto out; | |
522 | } | |
523 | } else if (vtag != asoc->c.peer_vtag) { | |
d1ad1ff2 SS |
524 | goto out; |
525 | } | |
1da177e4 LT |
526 | |
527 | sctp_bh_lock_sock(sk); | |
528 | ||
529 | /* If too many ICMPs get dropped on busy | |
530 | * servers this needs to be solved differently. | |
531 | */ | |
532 | if (sock_owned_by_user(sk)) | |
b01a2407 | 533 | NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS); |
1da177e4 | 534 | |
1da177e4 LT |
535 | *app = asoc; |
536 | *tpp = transport; | |
537 | return sk; | |
538 | ||
539 | out: | |
1da177e4 LT |
540 | if (asoc) |
541 | sctp_association_put(asoc); | |
1da177e4 LT |
542 | return NULL; |
543 | } | |
544 | ||
545 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 546 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
547 | { |
548 | sctp_bh_unlock_sock(sk); | |
1da177e4 LT |
549 | if (asoc) |
550 | sctp_association_put(asoc); | |
1da177e4 LT |
551 | } |
552 | ||
553 | /* | |
554 | * This routine is called by the ICMP module when it gets some | |
555 | * sort of error condition. If err < 0 then the socket should | |
556 | * be closed and the error returned to the user. If err > 0 | |
557 | * it's just the icmp type << 8 | icmp code. After adjustment | |
558 | * header points to the first 8 bytes of the sctp header. We need | |
559 | * to find the appropriate port. | |
560 | * | |
561 | * The locking strategy used here is very "optimistic". When | |
562 | * someone else accesses the socket the ICMP is just dropped | |
563 | * and for some paths there is no check at all. | |
564 | * A more general error queue to queue errors for later handling | |
565 | * is probably better. | |
566 | * | |
567 | */ | |
568 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
569 | { | |
b71d1d42 | 570 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
a27ef749 | 571 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
572 | const int type = icmp_hdr(skb)->type; |
573 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 574 | struct sock *sk; |
8de8c873 | 575 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
576 | struct sctp_transport *transport; |
577 | struct inet_sock *inet; | |
aef6de51 | 578 | __u16 saveip, savesctp; |
1da177e4 | 579 | int err; |
4110cc25 | 580 | struct net *net = dev_net(skb->dev); |
1da177e4 | 581 | |
a27ef749 | 582 | if (skb->len < ihlen + 8) { |
b01a2407 | 583 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
584 | return; |
585 | } | |
586 | ||
587 | /* Fix up skb to look at the embedded net header. */ | |
b0e380b1 ACM |
588 | saveip = skb->network_header; |
589 | savesctp = skb->transport_header; | |
31c7711b | 590 | skb_reset_network_header(skb); |
a27ef749 | 591 | skb_set_transport_header(skb, ihlen); |
4110cc25 | 592 | sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport); |
2e07fa9c | 593 | /* Put back, the original values. */ |
b0e380b1 ACM |
594 | skb->network_header = saveip; |
595 | skb->transport_header = savesctp; | |
1da177e4 | 596 | if (!sk) { |
b01a2407 | 597 | ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
598 | return; |
599 | } | |
600 | /* Warning: The sock lock is held. Remember to call | |
601 | * sctp_err_finish! | |
602 | */ | |
603 | ||
604 | switch (type) { | |
605 | case ICMP_PARAMETERPROB: | |
606 | err = EPROTO; | |
607 | break; | |
608 | case ICMP_DEST_UNREACH: | |
609 | if (code > NR_ICMP_UNREACH) | |
610 | goto out_unlock; | |
611 | ||
612 | /* PMTU discovery (RFC1191) */ | |
613 | if (ICMP_FRAG_NEEDED == code) { | |
614 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
615 | goto out_unlock; | |
616 | } | |
617 | else { | |
618 | if (ICMP_PROT_UNREACH == code) { | |
d1ad1ff2 | 619 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
620 | transport); |
621 | goto out_unlock; | |
622 | } | |
623 | } | |
624 | err = icmp_err_convert[code].errno; | |
625 | break; | |
626 | case ICMP_TIME_EXCEEDED: | |
627 | /* Ignore any time exceeded errors due to fragment reassembly | |
628 | * timeouts. | |
629 | */ | |
630 | if (ICMP_EXC_FRAGTIME == code) | |
631 | goto out_unlock; | |
632 | ||
633 | err = EHOSTUNREACH; | |
634 | break; | |
55be7a9c DM |
635 | case ICMP_REDIRECT: |
636 | sctp_icmp_redirect(sk, transport, skb); | |
637 | err = 0; | |
638 | break; | |
1da177e4 LT |
639 | default: |
640 | goto out_unlock; | |
641 | } | |
642 | ||
643 | inet = inet_sk(sk); | |
644 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
645 | sk->sk_err = err; | |
646 | sk->sk_error_report(sk); | |
647 | } else { /* Only an error on timeout */ | |
648 | sk->sk_err_soft = err; | |
649 | } | |
650 | ||
651 | out_unlock: | |
d1ad1ff2 | 652 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
653 | } |
654 | ||
655 | /* | |
656 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
657 | * | |
658 | * This function scans all the chunks in the OOTB packet to determine if | |
659 | * the packet should be discarded right away. If a response might be needed | |
660 | * for this packet, or, if further processing is possible, the packet will | |
661 | * be queued to a proper inqueue for the next phase of handling. | |
662 | * | |
663 | * Output: | |
664 | * Return 0 - If further processing is needed. | |
665 | * Return 1 - If the packet can be discarded right away. | |
666 | */ | |
04675210 | 667 | static int sctp_rcv_ootb(struct sk_buff *skb) |
1da177e4 LT |
668 | { |
669 | sctp_chunkhdr_t *ch; | |
670 | __u8 *ch_end; | |
1da177e4 LT |
671 | |
672 | ch = (sctp_chunkhdr_t *) skb->data; | |
1da177e4 LT |
673 | |
674 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 TF |
675 | do { |
676 | /* Break out if chunk length is less then minimal. */ | |
677 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
678 | break; | |
679 | ||
680 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
27a884dc | 681 | if (ch_end > skb_tail_pointer(skb)) |
a7d1f1b6 | 682 | break; |
1da177e4 LT |
683 | |
684 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
685 | * receiver MUST silently discard the OOTB packet and take no | |
686 | * further action. | |
687 | */ | |
688 | if (SCTP_CID_ABORT == ch->type) | |
689 | goto discard; | |
690 | ||
691 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
692 | * chunk, the receiver should silently discard the packet | |
693 | * and take no further action. | |
694 | */ | |
695 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
696 | goto discard; | |
697 | ||
3c77f961 VY |
698 | /* RFC 4460, 2.11.2 |
699 | * This will discard packets with INIT chunk bundled as | |
700 | * subsequent chunks in the packet. When INIT is first, | |
701 | * the normal INIT processing will discard the chunk. | |
702 | */ | |
703 | if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data) | |
704 | goto discard; | |
705 | ||
1da177e4 | 706 | ch = (sctp_chunkhdr_t *) ch_end; |
27a884dc | 707 | } while (ch_end < skb_tail_pointer(skb)); |
1da177e4 LT |
708 | |
709 | return 0; | |
710 | ||
711 | discard: | |
712 | return 1; | |
713 | } | |
714 | ||
715 | /* Insert endpoint into the hash table. */ | |
716 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
717 | { | |
4cdadcbc | 718 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
719 | struct sctp_ep_common *epb; |
720 | struct sctp_hashbucket *head; | |
721 | ||
722 | epb = &ep->base; | |
723 | ||
4cdadcbc | 724 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
725 | head = &sctp_ep_hashtable[epb->hashent]; |
726 | ||
727 | sctp_write_lock(&head->lock); | |
d970dbf8 | 728 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
729 | sctp_write_unlock(&head->lock); |
730 | } | |
731 | ||
732 | /* Add an endpoint to the hash. Local BH-safe. */ | |
733 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
734 | { | |
735 | sctp_local_bh_disable(); | |
736 | __sctp_hash_endpoint(ep); | |
737 | sctp_local_bh_enable(); | |
738 | } | |
739 | ||
740 | /* Remove endpoint from the hash table. */ | |
741 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
742 | { | |
4cdadcbc | 743 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
744 | struct sctp_hashbucket *head; |
745 | struct sctp_ep_common *epb; | |
746 | ||
747 | epb = &ep->base; | |
748 | ||
4cdadcbc | 749 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
750 | |
751 | head = &sctp_ep_hashtable[epb->hashent]; | |
752 | ||
753 | sctp_write_lock(&head->lock); | |
2eebc1e1 | 754 | hlist_del_init(&epb->node); |
1da177e4 LT |
755 | sctp_write_unlock(&head->lock); |
756 | } | |
757 | ||
758 | /* Remove endpoint from the hash. Local BH-safe. */ | |
759 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
760 | { | |
761 | sctp_local_bh_disable(); | |
762 | __sctp_unhash_endpoint(ep); | |
763 | sctp_local_bh_enable(); | |
764 | } | |
765 | ||
766 | /* Look up an endpoint. */ | |
4cdadcbc EB |
767 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net, |
768 | const union sctp_addr *laddr) | |
1da177e4 LT |
769 | { |
770 | struct sctp_hashbucket *head; | |
771 | struct sctp_ep_common *epb; | |
772 | struct sctp_endpoint *ep; | |
773 | int hash; | |
774 | ||
4cdadcbc | 775 | hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
776 | head = &sctp_ep_hashtable[hash]; |
777 | read_lock(&head->lock); | |
b67bfe0d | 778 | sctp_for_each_hentry(epb, &head->chain) { |
1da177e4 | 779 | ep = sctp_ep(epb); |
4cdadcbc | 780 | if (sctp_endpoint_is_match(ep, net, laddr)) |
1da177e4 LT |
781 | goto hit; |
782 | } | |
783 | ||
2ce95503 | 784 | ep = sctp_sk(net->sctp.ctl_sock)->ep; |
1da177e4 LT |
785 | |
786 | hit: | |
787 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
788 | read_unlock(&head->lock); |
789 | return ep; | |
790 | } | |
791 | ||
792 | /* Insert association into the hash table. */ | |
793 | static void __sctp_hash_established(struct sctp_association *asoc) | |
794 | { | |
4110cc25 | 795 | struct net *net = sock_net(asoc->base.sk); |
1da177e4 LT |
796 | struct sctp_ep_common *epb; |
797 | struct sctp_hashbucket *head; | |
798 | ||
799 | epb = &asoc->base; | |
800 | ||
801 | /* Calculate which chain this entry will belong to. */ | |
4110cc25 EB |
802 | epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port, |
803 | asoc->peer.port); | |
1da177e4 LT |
804 | |
805 | head = &sctp_assoc_hashtable[epb->hashent]; | |
806 | ||
807 | sctp_write_lock(&head->lock); | |
d970dbf8 | 808 | hlist_add_head(&epb->node, &head->chain); |
1da177e4 LT |
809 | sctp_write_unlock(&head->lock); |
810 | } | |
811 | ||
812 | /* Add an association to the hash. Local BH-safe. */ | |
813 | void sctp_hash_established(struct sctp_association *asoc) | |
814 | { | |
de76e695 VY |
815 | if (asoc->temp) |
816 | return; | |
817 | ||
1da177e4 LT |
818 | sctp_local_bh_disable(); |
819 | __sctp_hash_established(asoc); | |
820 | sctp_local_bh_enable(); | |
821 | } | |
822 | ||
823 | /* Remove association from the hash table. */ | |
824 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
825 | { | |
4110cc25 | 826 | struct net *net = sock_net(asoc->base.sk); |
1da177e4 LT |
827 | struct sctp_hashbucket *head; |
828 | struct sctp_ep_common *epb; | |
829 | ||
830 | epb = &asoc->base; | |
831 | ||
4110cc25 | 832 | epb->hashent = sctp_assoc_hashfn(net, epb->bind_addr.port, |
1da177e4 LT |
833 | asoc->peer.port); |
834 | ||
835 | head = &sctp_assoc_hashtable[epb->hashent]; | |
836 | ||
837 | sctp_write_lock(&head->lock); | |
2eebc1e1 | 838 | hlist_del_init(&epb->node); |
1da177e4 LT |
839 | sctp_write_unlock(&head->lock); |
840 | } | |
841 | ||
842 | /* Remove association from the hash table. Local BH-safe. */ | |
843 | void sctp_unhash_established(struct sctp_association *asoc) | |
844 | { | |
de76e695 VY |
845 | if (asoc->temp) |
846 | return; | |
847 | ||
1da177e4 LT |
848 | sctp_local_bh_disable(); |
849 | __sctp_unhash_established(asoc); | |
850 | sctp_local_bh_enable(); | |
851 | } | |
852 | ||
853 | /* Look up an association. */ | |
854 | static struct sctp_association *__sctp_lookup_association( | |
4110cc25 | 855 | struct net *net, |
1da177e4 LT |
856 | const union sctp_addr *local, |
857 | const union sctp_addr *peer, | |
858 | struct sctp_transport **pt) | |
859 | { | |
860 | struct sctp_hashbucket *head; | |
861 | struct sctp_ep_common *epb; | |
862 | struct sctp_association *asoc; | |
863 | struct sctp_transport *transport; | |
864 | int hash; | |
865 | ||
866 | /* Optimize here for direct hit, only listening connections can | |
867 | * have wildcards anyways. | |
868 | */ | |
4110cc25 EB |
869 | hash = sctp_assoc_hashfn(net, ntohs(local->v4.sin_port), |
870 | ntohs(peer->v4.sin_port)); | |
1da177e4 LT |
871 | head = &sctp_assoc_hashtable[hash]; |
872 | read_lock(&head->lock); | |
b67bfe0d | 873 | sctp_for_each_hentry(epb, &head->chain) { |
1da177e4 | 874 | asoc = sctp_assoc(epb); |
4110cc25 | 875 | transport = sctp_assoc_is_match(asoc, net, local, peer); |
1da177e4 LT |
876 | if (transport) |
877 | goto hit; | |
878 | } | |
879 | ||
880 | read_unlock(&head->lock); | |
881 | ||
882 | return NULL; | |
883 | ||
884 | hit: | |
885 | *pt = transport; | |
886 | sctp_association_hold(asoc); | |
1da177e4 LT |
887 | read_unlock(&head->lock); |
888 | return asoc; | |
889 | } | |
890 | ||
891 | /* Look up an association. BH-safe. */ | |
dda91928 | 892 | static |
4110cc25 EB |
893 | struct sctp_association *sctp_lookup_association(struct net *net, |
894 | const union sctp_addr *laddr, | |
1da177e4 | 895 | const union sctp_addr *paddr, |
dda91928 | 896 | struct sctp_transport **transportp) |
1da177e4 LT |
897 | { |
898 | struct sctp_association *asoc; | |
899 | ||
900 | sctp_local_bh_disable(); | |
4110cc25 | 901 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
1da177e4 LT |
902 | sctp_local_bh_enable(); |
903 | ||
904 | return asoc; | |
905 | } | |
906 | ||
907 | /* Is there an association matching the given local and peer addresses? */ | |
4110cc25 EB |
908 | int sctp_has_association(struct net *net, |
909 | const union sctp_addr *laddr, | |
1da177e4 LT |
910 | const union sctp_addr *paddr) |
911 | { | |
912 | struct sctp_association *asoc; | |
913 | struct sctp_transport *transport; | |
914 | ||
4110cc25 | 915 | if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) { |
1da177e4 LT |
916 | sctp_association_put(asoc); |
917 | return 1; | |
918 | } | |
919 | ||
920 | return 0; | |
921 | } | |
922 | ||
923 | /* | |
924 | * SCTP Implementors Guide, 2.18 Handling of address | |
925 | * parameters within the INIT or INIT-ACK. | |
926 | * | |
927 | * D) When searching for a matching TCB upon reception of an INIT | |
928 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
929 | * source address of the packet (containing the INIT or | |
930 | * INIT-ACK) but the receiver SHOULD also use all valid | |
931 | * address parameters contained within the chunk. | |
932 | * | |
933 | * 2.18.3 Solution description | |
934 | * | |
935 | * This new text clearly specifies to an implementor the need | |
936 | * to look within the INIT or INIT-ACK. Any implementation that | |
937 | * does not do this, may not be able to establish associations | |
938 | * in certain circumstances. | |
939 | * | |
940 | */ | |
4110cc25 EB |
941 | static struct sctp_association *__sctp_rcv_init_lookup(struct net *net, |
942 | struct sk_buff *skb, | |
1da177e4 LT |
943 | const union sctp_addr *laddr, struct sctp_transport **transportp) |
944 | { | |
945 | struct sctp_association *asoc; | |
946 | union sctp_addr addr; | |
947 | union sctp_addr *paddr = &addr; | |
2c0fd387 | 948 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
949 | union sctp_params params; |
950 | sctp_init_chunk_t *init; | |
951 | struct sctp_transport *transport; | |
952 | struct sctp_af *af; | |
953 | ||
1da177e4 LT |
954 | /* |
955 | * This code will NOT touch anything inside the chunk--it is | |
956 | * strictly READ-ONLY. | |
957 | * | |
958 | * RFC 2960 3 SCTP packet Format | |
959 | * | |
960 | * Multiple chunks can be bundled into one SCTP packet up to | |
961 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
962 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
963 | * other chunk in a packet. See Section 6.10 for more details | |
964 | * on chunk bundling. | |
965 | */ | |
966 | ||
967 | /* Find the start of the TLVs and the end of the chunk. This is | |
968 | * the region we search for address parameters. | |
969 | */ | |
970 | init = (sctp_init_chunk_t *)skb->data; | |
971 | ||
972 | /* Walk the parameters looking for embedded addresses. */ | |
973 | sctp_walk_params(params, init, init_hdr.params) { | |
974 | ||
975 | /* Note: Ignoring hostname addresses. */ | |
976 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
977 | if (!af) | |
978 | continue; | |
979 | ||
dd86d136 | 980 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 981 | |
4110cc25 | 982 | asoc = __sctp_lookup_association(net, laddr, paddr, &transport); |
1da177e4 LT |
983 | if (asoc) |
984 | return asoc; | |
985 | } | |
986 | ||
987 | return NULL; | |
988 | } | |
989 | ||
df218577 VY |
990 | /* ADD-IP, Section 5.2 |
991 | * When an endpoint receives an ASCONF Chunk from the remote peer | |
992 | * special procedures may be needed to identify the association the | |
993 | * ASCONF Chunk is associated with. To properly find the association | |
994 | * the following procedures SHOULD be followed: | |
995 | * | |
996 | * D2) If the association is not found, use the address found in the | |
997 | * Address Parameter TLV combined with the port number found in the | |
998 | * SCTP common header. If found proceed to rule D4. | |
999 | * | |
1000 | * D2-ext) If more than one ASCONF Chunks are packed together, use the | |
1001 | * address found in the ASCONF Address Parameter TLV of each of the | |
1002 | * subsequent ASCONF Chunks. If found, proceed to rule D4. | |
1003 | */ | |
1004 | static struct sctp_association *__sctp_rcv_asconf_lookup( | |
4110cc25 | 1005 | struct net *net, |
df218577 VY |
1006 | sctp_chunkhdr_t *ch, |
1007 | const union sctp_addr *laddr, | |
bc92dd19 | 1008 | __be16 peer_port, |
df218577 VY |
1009 | struct sctp_transport **transportp) |
1010 | { | |
1011 | sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch; | |
1012 | struct sctp_af *af; | |
1013 | union sctp_addr_param *param; | |
1014 | union sctp_addr paddr; | |
1015 | ||
1016 | /* Skip over the ADDIP header and find the Address parameter */ | |
1017 | param = (union sctp_addr_param *)(asconf + 1); | |
1018 | ||
6a435732 | 1019 | af = sctp_get_af_specific(param_type2af(param->p.type)); |
df218577 VY |
1020 | if (unlikely(!af)) |
1021 | return NULL; | |
1022 | ||
1023 | af->from_addr_param(&paddr, param, peer_port, 0); | |
1024 | ||
4110cc25 | 1025 | return __sctp_lookup_association(net, laddr, &paddr, transportp); |
df218577 VY |
1026 | } |
1027 | ||
1028 | ||
bbd0d598 VY |
1029 | /* SCTP-AUTH, Section 6.3: |
1030 | * If the receiver does not find a STCB for a packet containing an AUTH | |
1031 | * chunk as the first chunk and not a COOKIE-ECHO chunk as the second | |
1032 | * chunk, it MUST use the chunks after the AUTH chunk to look up an existing | |
1033 | * association. | |
1034 | * | |
1035 | * This means that any chunks that can help us identify the association need | |
25985edc | 1036 | * to be looked at to find this association. |
bbd0d598 | 1037 | */ |
4110cc25 EB |
1038 | static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net, |
1039 | struct sk_buff *skb, | |
bbd0d598 VY |
1040 | const union sctp_addr *laddr, |
1041 | struct sctp_transport **transportp) | |
1042 | { | |
df218577 VY |
1043 | struct sctp_association *asoc = NULL; |
1044 | sctp_chunkhdr_t *ch; | |
1045 | int have_auth = 0; | |
1046 | unsigned int chunk_num = 1; | |
1047 | __u8 *ch_end; | |
1048 | ||
1049 | /* Walk through the chunks looking for AUTH or ASCONF chunks | |
1050 | * to help us find the association. | |
bbd0d598 | 1051 | */ |
df218577 VY |
1052 | ch = (sctp_chunkhdr_t *) skb->data; |
1053 | do { | |
1054 | /* Break out if chunk length is less then minimal. */ | |
1055 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
1056 | break; | |
1057 | ||
1058 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
1059 | if (ch_end > skb_tail_pointer(skb)) | |
1060 | break; | |
1061 | ||
1062 | switch(ch->type) { | |
1063 | case SCTP_CID_AUTH: | |
1064 | have_auth = chunk_num; | |
1065 | break; | |
1066 | ||
1067 | case SCTP_CID_COOKIE_ECHO: | |
1068 | /* If a packet arrives containing an AUTH chunk as | |
1069 | * a first chunk, a COOKIE-ECHO chunk as the second | |
1070 | * chunk, and possibly more chunks after them, and | |
1071 | * the receiver does not have an STCB for that | |
1072 | * packet, then authentication is based on | |
1073 | * the contents of the COOKIE- ECHO chunk. | |
1074 | */ | |
1075 | if (have_auth == 1 && chunk_num == 2) | |
1076 | return NULL; | |
1077 | break; | |
1078 | ||
1079 | case SCTP_CID_ASCONF: | |
e1fc3b14 | 1080 | if (have_auth || net->sctp.addip_noauth) |
4110cc25 EB |
1081 | asoc = __sctp_rcv_asconf_lookup( |
1082 | net, ch, laddr, | |
df218577 VY |
1083 | sctp_hdr(skb)->source, |
1084 | transportp); | |
1085 | default: | |
1086 | break; | |
1087 | } | |
1088 | ||
1089 | if (asoc) | |
1090 | break; | |
1091 | ||
1092 | ch = (sctp_chunkhdr_t *) ch_end; | |
1093 | chunk_num++; | |
1094 | } while (ch_end < skb_tail_pointer(skb)); | |
1095 | ||
1096 | return asoc; | |
bbd0d598 VY |
1097 | } |
1098 | ||
1099 | /* | |
1100 | * There are circumstances when we need to look inside the SCTP packet | |
1101 | * for information to help us find the association. Examples | |
1102 | * include looking inside of INIT/INIT-ACK chunks or after the AUTH | |
1103 | * chunks. | |
1104 | */ | |
4110cc25 EB |
1105 | static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net, |
1106 | struct sk_buff *skb, | |
bbd0d598 VY |
1107 | const union sctp_addr *laddr, |
1108 | struct sctp_transport **transportp) | |
1109 | { | |
1110 | sctp_chunkhdr_t *ch; | |
1111 | ||
1112 | ch = (sctp_chunkhdr_t *) skb->data; | |
1113 | ||
df218577 VY |
1114 | /* The code below will attempt to walk the chunk and extract |
1115 | * parameter information. Before we do that, we need to verify | |
1116 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
1117 | * walk off the end. | |
1118 | */ | |
1119 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
1120 | return NULL; | |
1121 | ||
bbd0d598 VY |
1122 | /* If this is INIT/INIT-ACK look inside the chunk too. */ |
1123 | switch (ch->type) { | |
1124 | case SCTP_CID_INIT: | |
1125 | case SCTP_CID_INIT_ACK: | |
4110cc25 | 1126 | return __sctp_rcv_init_lookup(net, skb, laddr, transportp); |
bbd0d598 VY |
1127 | break; |
1128 | ||
df218577 | 1129 | default: |
4110cc25 | 1130 | return __sctp_rcv_walk_lookup(net, skb, laddr, transportp); |
bbd0d598 VY |
1131 | break; |
1132 | } | |
1133 | ||
df218577 | 1134 | |
bbd0d598 VY |
1135 | return NULL; |
1136 | } | |
1137 | ||
1da177e4 | 1138 | /* Lookup an association for an inbound skb. */ |
4110cc25 EB |
1139 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
1140 | struct sk_buff *skb, | |
1da177e4 LT |
1141 | const union sctp_addr *paddr, |
1142 | const union sctp_addr *laddr, | |
1143 | struct sctp_transport **transportp) | |
1144 | { | |
1145 | struct sctp_association *asoc; | |
1146 | ||
4110cc25 | 1147 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
1da177e4 LT |
1148 | |
1149 | /* Further lookup for INIT/INIT-ACK packets. | |
1150 | * SCTP Implementors Guide, 2.18 Handling of address | |
1151 | * parameters within the INIT or INIT-ACK. | |
1152 | */ | |
1153 | if (!asoc) | |
4110cc25 | 1154 | asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp); |
1da177e4 LT |
1155 | |
1156 | return asoc; | |
1157 | } |