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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. */ | |
08e3baef | 87 | __SCTP_INC_STATS(net, SCTP_MIB_CHECKSUMERRORS); |
1da177e4 LT |
88 | return -1; |
89 | } | |
90 | return 0; | |
91 | } | |
92 | ||
1da177e4 LT |
93 | /* |
94 | * This is the routine which IP calls when receiving an SCTP packet. | |
95 | */ | |
96 | int sctp_rcv(struct sk_buff *skb) | |
97 | { | |
98 | struct sock *sk; | |
99 | struct sctp_association *asoc; | |
100 | struct sctp_endpoint *ep = NULL; | |
101 | struct sctp_ep_common *rcvr; | |
102 | struct sctp_transport *transport = NULL; | |
103 | struct sctp_chunk *chunk; | |
1da177e4 LT |
104 | union sctp_addr src; |
105 | union sctp_addr dest; | |
106 | int family; | |
107 | struct sctp_af *af; | |
4cdadcbc | 108 | struct net *net = dev_net(skb->dev); |
1da177e4 | 109 | |
cb3f837b | 110 | if (skb->pkt_type != PACKET_HOST) |
1da177e4 LT |
111 | goto discard_it; |
112 | ||
08e3baef | 113 | __SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS); |
1da177e4 | 114 | |
3acb50c1 MRL |
115 | /* If packet is too small to contain a single chunk, let's not |
116 | * waste time on it anymore. | |
117 | */ | |
118 | if (skb->len < sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) + | |
119 | skb_transport_offset(skb)) | |
28cd7752 HX |
120 | goto discard_it; |
121 | ||
3acb50c1 MRL |
122 | if (!pskb_may_pull(skb, sizeof(struct sctphdr))) |
123 | goto discard_it; | |
1da177e4 | 124 | |
3acb50c1 | 125 | /* Pull up the IP header. */ |
ea2ae17d | 126 | __skb_pull(skb, skb_transport_offset(skb)); |
202863fe TH |
127 | |
128 | skb->csum_valid = 0; /* Previous value not applicable */ | |
129 | if (skb_csum_unnecessary(skb)) | |
130 | __skb_decr_checksum_unnecessary(skb); | |
90017acc MRL |
131 | else if (!sctp_checksum_disable && |
132 | !(skb_shinfo(skb)->gso_type & SKB_GSO_SCTP) && | |
133 | sctp_rcv_checksum(net, skb) < 0) | |
1da177e4 | 134 | goto discard_it; |
202863fe | 135 | skb->csum_valid = 1; |
1da177e4 | 136 | |
3acb50c1 | 137 | __skb_pull(skb, sizeof(struct sctphdr)); |
1da177e4 | 138 | |
eddc9ec5 | 139 | family = ipver2af(ip_hdr(skb)->version); |
1da177e4 LT |
140 | af = sctp_get_af_specific(family); |
141 | if (unlikely(!af)) | |
142 | goto discard_it; | |
e7487c86 | 143 | SCTP_INPUT_CB(skb)->af = af; |
1da177e4 LT |
144 | |
145 | /* Initialize local addresses for lookups. */ | |
146 | af->from_skb(&src, skb, 1); | |
147 | af->from_skb(&dest, skb, 0); | |
148 | ||
149 | /* If the packet is to or from a non-unicast address, | |
150 | * silently discard the packet. | |
151 | * | |
152 | * This is not clearly defined in the RFC except in section | |
153 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
154 | * Transmission Protocol" 2.1, "It is important to note that the | |
155 | * IP address of an SCTP transport address must be a routable | |
156 | * unicast address. In other words, IP multicast addresses and | |
157 | * IP broadcast addresses cannot be used in an SCTP transport | |
158 | * address." | |
159 | */ | |
5636bef7 VY |
160 | if (!af->addr_valid(&src, NULL, skb) || |
161 | !af->addr_valid(&dest, NULL, skb)) | |
1da177e4 LT |
162 | goto discard_it; |
163 | ||
4110cc25 | 164 | asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport); |
1c7d1fc1 | 165 | |
0fd9a65a | 166 | if (!asoc) |
4cdadcbc | 167 | ep = __sctp_rcv_lookup_endpoint(net, &dest); |
0fd9a65a NH |
168 | |
169 | /* Retrieve the common input handling substructure. */ | |
170 | rcvr = asoc ? &asoc->base : &ep->base; | |
171 | sk = rcvr->sk; | |
172 | ||
173 | /* | |
174 | * If a frame arrives on an interface and the receiving socket is | |
175 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
176 | */ | |
8d72651d | 177 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) { |
0fd9a65a NH |
178 | if (asoc) { |
179 | sctp_association_put(asoc); | |
180 | asoc = NULL; | |
181 | } else { | |
182 | sctp_endpoint_put(ep); | |
183 | ep = NULL; | |
184 | } | |
2ce95503 | 185 | sk = net->sctp.ctl_sock; |
0fd9a65a NH |
186 | ep = sctp_sk(sk)->ep; |
187 | sctp_endpoint_hold(ep); | |
0fd9a65a NH |
188 | rcvr = &ep->base; |
189 | } | |
190 | ||
1da177e4 LT |
191 | /* |
192 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
193 | * An SCTP packet is called an "out of the blue" (OOTB) | |
194 | * packet if it is correctly formed, i.e., passed the | |
195 | * receiver's checksum check, but the receiver is not | |
196 | * able to identify the association to which this | |
197 | * packet belongs. | |
198 | */ | |
199 | if (!asoc) { | |
1da177e4 | 200 | if (sctp_rcv_ootb(skb)) { |
08e3baef | 201 | __SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); |
1da177e4 LT |
202 | goto discard_release; |
203 | } | |
204 | } | |
205 | ||
1da177e4 LT |
206 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
207 | goto discard_release; | |
b59c2701 | 208 | nf_reset(skb); |
1da177e4 | 209 | |
fda9ef5d | 210 | if (sk_filter(sk, skb)) |
d808ad9a | 211 | goto discard_release; |
1da177e4 LT |
212 | |
213 | /* Create an SCTP packet structure. */ | |
cea8768f | 214 | chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC); |
2babf9da | 215 | if (!chunk) |
1da177e4 | 216 | goto discard_release; |
79af02c2 | 217 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 218 | |
1da177e4 LT |
219 | /* Remember what endpoint is to handle this packet. */ |
220 | chunk->rcvr = rcvr; | |
221 | ||
222 | /* Remember the SCTP header. */ | |
3acb50c1 | 223 | chunk->sctp_hdr = sctp_hdr(skb); |
1da177e4 LT |
224 | |
225 | /* Set the source and destination addresses of the incoming chunk. */ | |
d55c41b1 | 226 | sctp_init_addrs(chunk, &src, &dest); |
1da177e4 LT |
227 | |
228 | /* Remember where we came from. */ | |
229 | chunk->transport = transport; | |
230 | ||
231 | /* Acquire access to the sock lock. Note: We are safe from other | |
232 | * bottom halves on this lock, but a user may be in the lock too, | |
233 | * so check if it is busy. | |
234 | */ | |
5bc1d1b4 | 235 | bh_lock_sock(sk); |
1da177e4 | 236 | |
ae53b5bd VY |
237 | if (sk != rcvr->sk) { |
238 | /* Our cached sk is different from the rcvr->sk. This is | |
239 | * because migrate()/accept() may have moved the association | |
240 | * to a new socket and released all the sockets. So now we | |
241 | * are holding a lock on the old socket while the user may | |
242 | * be doing something with the new socket. Switch our veiw | |
243 | * of the current sk. | |
244 | */ | |
5bc1d1b4 | 245 | bh_unlock_sock(sk); |
ae53b5bd | 246 | sk = rcvr->sk; |
5bc1d1b4 | 247 | bh_lock_sock(sk); |
ae53b5bd VY |
248 | } |
249 | ||
ac0b0462 | 250 | if (sock_owned_by_user(sk)) { |
50b1a782 | 251 | if (sctp_add_backlog(sk, skb)) { |
5bc1d1b4 | 252 | bh_unlock_sock(sk); |
50b1a782 ZY |
253 | sctp_chunk_free(chunk); |
254 | skb = NULL; /* sctp_chunk_free already freed the skb */ | |
255 | goto discard_release; | |
256 | } | |
08e3baef | 257 | __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG); |
ac0b0462 | 258 | } else { |
08e3baef | 259 | __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ); |
61c9fed4 | 260 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 261 | } |
1da177e4 | 262 | |
5bc1d1b4 | 263 | bh_unlock_sock(sk); |
61c9fed4 VY |
264 | |
265 | /* Release the asoc/ep ref we took in the lookup calls. */ | |
266 | if (asoc) | |
267 | sctp_association_put(asoc); | |
268 | else | |
269 | sctp_endpoint_put(ep); | |
7a48f923 | 270 | |
2babf9da | 271 | return 0; |
1da177e4 LT |
272 | |
273 | discard_it: | |
08e3baef | 274 | __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); |
1da177e4 | 275 | kfree_skb(skb); |
2babf9da | 276 | return 0; |
1da177e4 LT |
277 | |
278 | discard_release: | |
61c9fed4 | 279 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 280 | if (asoc) |
1da177e4 | 281 | sctp_association_put(asoc); |
0fd9a65a | 282 | else |
1da177e4 | 283 | sctp_endpoint_put(ep); |
1da177e4 LT |
284 | |
285 | goto discard_it; | |
286 | } | |
287 | ||
61c9fed4 VY |
288 | /* Process the backlog queue of the socket. Every skb on |
289 | * the backlog holds a ref on an association or endpoint. | |
290 | * We hold this ref throughout the state machine to make | |
291 | * sure that the structure we need is still around. | |
1da177e4 LT |
292 | */ |
293 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
294 | { | |
79af02c2 | 295 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
d808ad9a YH |
296 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
297 | struct sctp_ep_common *rcvr = NULL; | |
61c9fed4 | 298 | int backloged = 0; |
7a48f923 | 299 | |
d808ad9a | 300 | rcvr = chunk->rcvr; |
c4d2444e | 301 | |
61c9fed4 VY |
302 | /* If the rcvr is dead then the association or endpoint |
303 | * has been deleted and we can safely drop the chunk | |
304 | * and refs that we are holding. | |
305 | */ | |
306 | if (rcvr->dead) { | |
307 | sctp_chunk_free(chunk); | |
308 | goto done; | |
309 | } | |
310 | ||
311 | if (unlikely(rcvr->sk != sk)) { | |
312 | /* In this case, the association moved from one socket to | |
313 | * another. We are currently sitting on the backlog of the | |
314 | * old socket, so we need to move. | |
315 | * However, since we are here in the process context we | |
316 | * need to take make sure that the user doesn't own | |
317 | * the new socket when we process the packet. | |
318 | * If the new socket is user-owned, queue the chunk to the | |
319 | * backlog of the new socket without dropping any refs. | |
320 | * Otherwise, we can safely push the chunk on the inqueue. | |
321 | */ | |
322 | ||
323 | sk = rcvr->sk; | |
eefc1b1d | 324 | local_bh_disable(); |
5bc1d1b4 | 325 | bh_lock_sock(sk); |
61c9fed4 VY |
326 | |
327 | if (sock_owned_by_user(sk)) { | |
f545a38f | 328 | if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) |
50b1a782 ZY |
329 | sctp_chunk_free(chunk); |
330 | else | |
331 | backloged = 1; | |
61c9fed4 VY |
332 | } else |
333 | sctp_inq_push(inqueue, chunk); | |
334 | ||
5bc1d1b4 | 335 | bh_unlock_sock(sk); |
eefc1b1d | 336 | local_bh_enable(); |
61c9fed4 VY |
337 | |
338 | /* If the chunk was backloged again, don't drop refs */ | |
339 | if (backloged) | |
340 | return 0; | |
341 | } else { | |
342 | sctp_inq_push(inqueue, chunk); | |
343 | } | |
344 | ||
345 | done: | |
346 | /* Release the refs we took in sctp_add_backlog */ | |
347 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
348 | sctp_association_put(sctp_assoc(rcvr)); | |
349 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
350 | sctp_endpoint_put(sctp_ep(rcvr)); | |
351 | else | |
352 | BUG(); | |
353 | ||
d808ad9a | 354 | return 0; |
1da177e4 LT |
355 | } |
356 | ||
50b1a782 | 357 | static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 358 | { |
61c9fed4 VY |
359 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
360 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
50b1a782 | 361 | int ret; |
c4d2444e | 362 | |
f545a38f | 363 | ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf); |
50b1a782 ZY |
364 | if (!ret) { |
365 | /* Hold the assoc/ep while hanging on the backlog queue. | |
366 | * This way, we know structures we need will not disappear | |
367 | * from us | |
368 | */ | |
369 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
370 | sctp_association_hold(sctp_assoc(rcvr)); | |
371 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
372 | sctp_endpoint_hold(sctp_ep(rcvr)); | |
373 | else | |
374 | BUG(); | |
375 | } | |
376 | return ret; | |
61c9fed4 | 377 | |
c4d2444e SS |
378 | } |
379 | ||
1da177e4 LT |
380 | /* Handle icmp frag needed error. */ |
381 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
382 | struct sctp_transport *t, __u32 pmtu) | |
383 | { | |
91bd6b1e | 384 | if (!t || (t->pathmtu <= pmtu)) |
52ccb8e9 FF |
385 | return; |
386 | ||
8a479491 VY |
387 | if (sock_owned_by_user(sk)) { |
388 | asoc->pmtu_pending = 1; | |
389 | t->pmtu_pending = 1; | |
390 | return; | |
391 | } | |
392 | ||
52ccb8e9 | 393 | if (t->param_flags & SPP_PMTUD_ENABLE) { |
c910b47e | 394 | /* Update transports view of the MTU */ |
02f3d4ce | 395 | sctp_transport_update_pmtu(sk, t, pmtu); |
1da177e4 | 396 | |
52ccb8e9 | 397 | /* Update association pmtu. */ |
02f3d4ce | 398 | sctp_assoc_sync_pmtu(sk, asoc); |
1da177e4 | 399 | } |
52ccb8e9 FF |
400 | |
401 | /* Retransmit with the new pmtu setting. | |
402 | * Normally, if PMTU discovery is disabled, an ICMP Fragmentation | |
403 | * Needed will never be sent, but if a message was sent before | |
404 | * PMTU discovery was disabled that was larger than the PMTU, it | |
d808ad9a | 405 | * would not be fragmented, so it must be re-transmitted fragmented. |
52ccb8e9 FF |
406 | */ |
407 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
408 | } |
409 | ||
ec18d9a2 DM |
410 | void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, |
411 | struct sk_buff *skb) | |
55be7a9c DM |
412 | { |
413 | struct dst_entry *dst; | |
414 | ||
415 | if (!t) | |
416 | return; | |
417 | dst = sctp_transport_dst_check(t); | |
1ed5c48f | 418 | if (dst) |
6700c270 | 419 | dst->ops->redirect(dst, sk, skb); |
55be7a9c DM |
420 | } |
421 | ||
1da177e4 LT |
422 | /* |
423 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
424 | * | |
425 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
426 | * or a "Protocol Unreachable" treat this message as an abort | |
427 | * with the T bit set. | |
428 | * | |
429 | * This function sends an event to the state machine, which will abort the | |
430 | * association. | |
431 | * | |
432 | */ | |
433 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
d808ad9a YH |
434 | struct sctp_association *asoc, |
435 | struct sctp_transport *t) | |
1da177e4 | 436 | { |
50b5d6ad VY |
437 | if (sock_owned_by_user(sk)) { |
438 | if (timer_pending(&t->proto_unreach_timer)) | |
439 | return; | |
440 | else { | |
441 | if (!mod_timer(&t->proto_unreach_timer, | |
442 | jiffies + (HZ/20))) | |
443 | sctp_association_hold(asoc); | |
444 | } | |
50b5d6ad | 445 | } else { |
55e26eb9 EB |
446 | struct net *net = sock_net(sk); |
447 | ||
bb33381d DB |
448 | pr_debug("%s: unrecognized next header type " |
449 | "encountered!\n", __func__); | |
450 | ||
25cc4ae9 | 451 | if (del_timer(&t->proto_unreach_timer)) |
50b5d6ad | 452 | sctp_association_put(asoc); |
1da177e4 | 453 | |
55e26eb9 | 454 | sctp_do_sm(net, SCTP_EVENT_T_OTHER, |
50b5d6ad VY |
455 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), |
456 | asoc->state, asoc->ep, asoc, t, | |
457 | GFP_ATOMIC); | |
458 | } | |
1da177e4 LT |
459 | } |
460 | ||
461 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
4110cc25 | 462 | struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb, |
1da177e4 | 463 | struct sctphdr *sctphdr, |
1da177e4 LT |
464 | struct sctp_association **app, |
465 | struct sctp_transport **tpp) | |
466 | { | |
467 | union sctp_addr saddr; | |
468 | union sctp_addr daddr; | |
469 | struct sctp_af *af; | |
470 | struct sock *sk = NULL; | |
8de8c873 | 471 | struct sctp_association *asoc; |
1da177e4 | 472 | struct sctp_transport *transport = NULL; |
7115e632 WY |
473 | struct sctp_init_chunk *chunkhdr; |
474 | __u32 vtag = ntohl(sctphdr->vtag); | |
475 | int len = skb->len - ((void *)sctphdr - (void *)skb->data); | |
1da177e4 | 476 | |
d1ad1ff2 | 477 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
478 | |
479 | af = sctp_get_af_specific(family); | |
480 | if (unlikely(!af)) { | |
481 | return NULL; | |
482 | } | |
483 | ||
484 | /* Initialize local addresses for lookups. */ | |
485 | af->from_skb(&saddr, skb, 1); | |
486 | af->from_skb(&daddr, skb, 0); | |
487 | ||
488 | /* Look for an association that matches the incoming ICMP error | |
489 | * packet. | |
490 | */ | |
4110cc25 | 491 | asoc = __sctp_lookup_association(net, &saddr, &daddr, &transport); |
d1ad1ff2 SS |
492 | if (!asoc) |
493 | return NULL; | |
1da177e4 | 494 | |
d1ad1ff2 | 495 | sk = asoc->base.sk; |
1da177e4 | 496 | |
7115e632 WY |
497 | /* RFC 4960, Appendix C. ICMP Handling |
498 | * | |
499 | * ICMP6) An implementation MUST validate that the Verification Tag | |
500 | * contained in the ICMP message matches the Verification Tag of | |
501 | * the peer. If the Verification Tag is not 0 and does NOT | |
502 | * match, discard the ICMP message. If it is 0 and the ICMP | |
503 | * message contains enough bytes to verify that the chunk type is | |
504 | * an INIT chunk and that the Initiate Tag matches the tag of the | |
505 | * peer, continue with ICMP7. If the ICMP message is too short | |
506 | * or the chunk type or the Initiate Tag does not match, silently | |
507 | * discard the packet. | |
508 | */ | |
509 | if (vtag == 0) { | |
ea110733 | 510 | chunkhdr = (void *)sctphdr + sizeof(struct sctphdr); |
7115e632 WY |
511 | if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t) |
512 | + sizeof(__be32) || | |
513 | chunkhdr->chunk_hdr.type != SCTP_CID_INIT || | |
514 | ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) { | |
515 | goto out; | |
516 | } | |
517 | } else if (vtag != asoc->c.peer_vtag) { | |
d1ad1ff2 SS |
518 | goto out; |
519 | } | |
1da177e4 | 520 | |
5bc1d1b4 | 521 | bh_lock_sock(sk); |
1da177e4 LT |
522 | |
523 | /* If too many ICMPs get dropped on busy | |
524 | * servers this needs to be solved differently. | |
525 | */ | |
526 | if (sock_owned_by_user(sk)) | |
02a1d6e7 | 527 | __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); |
1da177e4 | 528 | |
1da177e4 LT |
529 | *app = asoc; |
530 | *tpp = transport; | |
531 | return sk; | |
532 | ||
533 | out: | |
e4772668 | 534 | sctp_association_put(asoc); |
1da177e4 LT |
535 | return NULL; |
536 | } | |
537 | ||
538 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 539 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 | 540 | { |
5bc1d1b4 | 541 | bh_unlock_sock(sk); |
e4772668 | 542 | sctp_association_put(asoc); |
1da177e4 LT |
543 | } |
544 | ||
545 | /* | |
546 | * This routine is called by the ICMP module when it gets some | |
547 | * sort of error condition. If err < 0 then the socket should | |
548 | * be closed and the error returned to the user. If err > 0 | |
549 | * it's just the icmp type << 8 | icmp code. After adjustment | |
550 | * header points to the first 8 bytes of the sctp header. We need | |
551 | * to find the appropriate port. | |
552 | * | |
553 | * The locking strategy used here is very "optimistic". When | |
554 | * someone else accesses the socket the ICMP is just dropped | |
555 | * and for some paths there is no check at all. | |
556 | * A more general error queue to queue errors for later handling | |
557 | * is probably better. | |
558 | * | |
559 | */ | |
560 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
561 | { | |
b71d1d42 | 562 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
a27ef749 | 563 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
564 | const int type = icmp_hdr(skb)->type; |
565 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 566 | struct sock *sk; |
8de8c873 | 567 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
568 | struct sctp_transport *transport; |
569 | struct inet_sock *inet; | |
aef6de51 | 570 | __u16 saveip, savesctp; |
1da177e4 | 571 | int err; |
4110cc25 | 572 | struct net *net = dev_net(skb->dev); |
1da177e4 | 573 | |
1da177e4 | 574 | /* Fix up skb to look at the embedded net header. */ |
b0e380b1 ACM |
575 | saveip = skb->network_header; |
576 | savesctp = skb->transport_header; | |
31c7711b | 577 | skb_reset_network_header(skb); |
a27ef749 | 578 | skb_set_transport_header(skb, ihlen); |
4110cc25 | 579 | sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport); |
2e07fa9c | 580 | /* Put back, the original values. */ |
b0e380b1 ACM |
581 | skb->network_header = saveip; |
582 | skb->transport_header = savesctp; | |
1da177e4 | 583 | if (!sk) { |
5d3848bc | 584 | __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
585 | return; |
586 | } | |
587 | /* Warning: The sock lock is held. Remember to call | |
588 | * sctp_err_finish! | |
589 | */ | |
590 | ||
591 | switch (type) { | |
592 | case ICMP_PARAMETERPROB: | |
593 | err = EPROTO; | |
594 | break; | |
595 | case ICMP_DEST_UNREACH: | |
596 | if (code > NR_ICMP_UNREACH) | |
597 | goto out_unlock; | |
598 | ||
599 | /* PMTU discovery (RFC1191) */ | |
600 | if (ICMP_FRAG_NEEDED == code) { | |
3822a5ff MRL |
601 | sctp_icmp_frag_needed(sk, asoc, transport, |
602 | WORD_TRUNC(info)); | |
1da177e4 | 603 | goto out_unlock; |
8d72651d | 604 | } else { |
1da177e4 | 605 | if (ICMP_PROT_UNREACH == code) { |
d1ad1ff2 | 606 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
607 | transport); |
608 | goto out_unlock; | |
609 | } | |
610 | } | |
611 | err = icmp_err_convert[code].errno; | |
612 | break; | |
613 | case ICMP_TIME_EXCEEDED: | |
614 | /* Ignore any time exceeded errors due to fragment reassembly | |
615 | * timeouts. | |
616 | */ | |
617 | if (ICMP_EXC_FRAGTIME == code) | |
618 | goto out_unlock; | |
619 | ||
620 | err = EHOSTUNREACH; | |
621 | break; | |
55be7a9c DM |
622 | case ICMP_REDIRECT: |
623 | sctp_icmp_redirect(sk, transport, skb); | |
3f96a532 | 624 | /* Fall through to out_unlock. */ |
1da177e4 LT |
625 | default: |
626 | goto out_unlock; | |
627 | } | |
628 | ||
629 | inet = inet_sk(sk); | |
630 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
631 | sk->sk_err = err; | |
632 | sk->sk_error_report(sk); | |
633 | } else { /* Only an error on timeout */ | |
634 | sk->sk_err_soft = err; | |
635 | } | |
636 | ||
637 | out_unlock: | |
d1ad1ff2 | 638 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
639 | } |
640 | ||
641 | /* | |
642 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
643 | * | |
644 | * This function scans all the chunks in the OOTB packet to determine if | |
645 | * the packet should be discarded right away. If a response might be needed | |
646 | * for this packet, or, if further processing is possible, the packet will | |
647 | * be queued to a proper inqueue for the next phase of handling. | |
648 | * | |
649 | * Output: | |
650 | * Return 0 - If further processing is needed. | |
651 | * Return 1 - If the packet can be discarded right away. | |
652 | */ | |
04675210 | 653 | static int sctp_rcv_ootb(struct sk_buff *skb) |
1da177e4 | 654 | { |
3acb50c1 MRL |
655 | sctp_chunkhdr_t *ch, _ch; |
656 | int ch_end, offset = 0; | |
1da177e4 LT |
657 | |
658 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 | 659 | do { |
3acb50c1 MRL |
660 | /* Make sure we have at least the header there */ |
661 | if (offset + sizeof(sctp_chunkhdr_t) > skb->len) | |
662 | break; | |
663 | ||
664 | ch = skb_header_pointer(skb, offset, sizeof(*ch), &_ch); | |
665 | ||
a7d1f1b6 TF |
666 | /* Break out if chunk length is less then minimal. */ |
667 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
668 | break; | |
669 | ||
3acb50c1 MRL |
670 | ch_end = offset + WORD_ROUND(ntohs(ch->length)); |
671 | if (ch_end > skb->len) | |
a7d1f1b6 | 672 | break; |
1da177e4 LT |
673 | |
674 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
675 | * receiver MUST silently discard the OOTB packet and take no | |
676 | * further action. | |
677 | */ | |
678 | if (SCTP_CID_ABORT == ch->type) | |
679 | goto discard; | |
680 | ||
681 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
682 | * chunk, the receiver should silently discard the packet | |
683 | * and take no further action. | |
684 | */ | |
685 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
686 | goto discard; | |
687 | ||
3c77f961 VY |
688 | /* RFC 4460, 2.11.2 |
689 | * This will discard packets with INIT chunk bundled as | |
690 | * subsequent chunks in the packet. When INIT is first, | |
691 | * the normal INIT processing will discard the chunk. | |
692 | */ | |
693 | if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data) | |
694 | goto discard; | |
695 | ||
3acb50c1 MRL |
696 | offset = ch_end; |
697 | } while (ch_end < skb->len); | |
1da177e4 LT |
698 | |
699 | return 0; | |
700 | ||
701 | discard: | |
702 | return 1; | |
703 | } | |
704 | ||
705 | /* Insert endpoint into the hash table. */ | |
706 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
707 | { | |
4cdadcbc | 708 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
709 | struct sctp_ep_common *epb; |
710 | struct sctp_hashbucket *head; | |
711 | ||
712 | epb = &ep->base; | |
713 | ||
4cdadcbc | 714 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
715 | head = &sctp_ep_hashtable[epb->hashent]; |
716 | ||
387602df | 717 | write_lock(&head->lock); |
d970dbf8 | 718 | hlist_add_head(&epb->node, &head->chain); |
387602df | 719 | write_unlock(&head->lock); |
1da177e4 LT |
720 | } |
721 | ||
722 | /* Add an endpoint to the hash. Local BH-safe. */ | |
723 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
724 | { | |
79b91130 | 725 | local_bh_disable(); |
1da177e4 | 726 | __sctp_hash_endpoint(ep); |
79b91130 | 727 | local_bh_enable(); |
1da177e4 LT |
728 | } |
729 | ||
730 | /* Remove endpoint from the hash table. */ | |
731 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
732 | { | |
4cdadcbc | 733 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
734 | struct sctp_hashbucket *head; |
735 | struct sctp_ep_common *epb; | |
736 | ||
737 | epb = &ep->base; | |
738 | ||
4cdadcbc | 739 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
740 | |
741 | head = &sctp_ep_hashtable[epb->hashent]; | |
742 | ||
387602df | 743 | write_lock(&head->lock); |
2eebc1e1 | 744 | hlist_del_init(&epb->node); |
387602df | 745 | write_unlock(&head->lock); |
1da177e4 LT |
746 | } |
747 | ||
748 | /* Remove endpoint from the hash. Local BH-safe. */ | |
749 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
750 | { | |
79b91130 | 751 | local_bh_disable(); |
1da177e4 | 752 | __sctp_unhash_endpoint(ep); |
79b91130 | 753 | local_bh_enable(); |
1da177e4 LT |
754 | } |
755 | ||
756 | /* Look up an endpoint. */ | |
4cdadcbc EB |
757 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net, |
758 | const union sctp_addr *laddr) | |
1da177e4 LT |
759 | { |
760 | struct sctp_hashbucket *head; | |
761 | struct sctp_ep_common *epb; | |
762 | struct sctp_endpoint *ep; | |
763 | int hash; | |
764 | ||
4cdadcbc | 765 | hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
766 | head = &sctp_ep_hashtable[hash]; |
767 | read_lock(&head->lock); | |
b67bfe0d | 768 | sctp_for_each_hentry(epb, &head->chain) { |
1da177e4 | 769 | ep = sctp_ep(epb); |
4cdadcbc | 770 | if (sctp_endpoint_is_match(ep, net, laddr)) |
1da177e4 LT |
771 | goto hit; |
772 | } | |
773 | ||
2ce95503 | 774 | ep = sctp_sk(net->sctp.ctl_sock)->ep; |
1da177e4 LT |
775 | |
776 | hit: | |
777 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
778 | read_unlock(&head->lock); |
779 | return ep; | |
780 | } | |
781 | ||
d6c0256a XL |
782 | /* rhashtable for transport */ |
783 | struct sctp_hash_cmp_arg { | |
65a5124a | 784 | const struct sctp_endpoint *ep; |
d6c0256a XL |
785 | const union sctp_addr *laddr; |
786 | const union sctp_addr *paddr; | |
787 | const struct net *net; | |
788 | }; | |
789 | ||
790 | static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg, | |
791 | const void *ptr) | |
792 | { | |
793 | const struct sctp_hash_cmp_arg *x = arg->key; | |
794 | const struct sctp_transport *t = ptr; | |
795 | struct sctp_association *asoc = t->asoc; | |
796 | const struct net *net = x->net; | |
797 | ||
d6c0256a XL |
798 | if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr)) |
799 | return 1; | |
800 | if (!net_eq(sock_net(asoc->base.sk), net)) | |
801 | return 1; | |
65a5124a XL |
802 | if (x->ep) { |
803 | if (x->ep != asoc->ep) | |
804 | return 1; | |
805 | } else { | |
806 | if (x->laddr->v4.sin_port != htons(asoc->base.bind_addr.port)) | |
807 | return 1; | |
808 | if (!sctp_bind_addr_match(&asoc->base.bind_addr, | |
809 | x->laddr, sctp_sk(asoc->base.sk))) | |
810 | return 1; | |
811 | } | |
d6c0256a XL |
812 | |
813 | return 0; | |
814 | } | |
815 | ||
816 | static inline u32 sctp_hash_obj(const void *data, u32 len, u32 seed) | |
817 | { | |
818 | const struct sctp_transport *t = data; | |
819 | const union sctp_addr *paddr = &t->ipaddr; | |
820 | const struct net *net = sock_net(t->asoc->base.sk); | |
821 | u16 lport = htons(t->asoc->base.bind_addr.port); | |
822 | u32 addr; | |
823 | ||
824 | if (paddr->sa.sa_family == AF_INET6) | |
825 | addr = jhash(&paddr->v6.sin6_addr, 16, seed); | |
826 | else | |
827 | addr = paddr->v4.sin_addr.s_addr; | |
828 | ||
829 | return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 | | |
830 | (__force __u32)lport, net_hash_mix(net), seed); | |
831 | } | |
832 | ||
833 | static inline u32 sctp_hash_key(const void *data, u32 len, u32 seed) | |
834 | { | |
835 | const struct sctp_hash_cmp_arg *x = data; | |
836 | const union sctp_addr *paddr = x->paddr; | |
837 | const struct net *net = x->net; | |
65a5124a | 838 | u16 lport; |
d6c0256a XL |
839 | u32 addr; |
840 | ||
65a5124a XL |
841 | lport = x->ep ? htons(x->ep->base.bind_addr.port) : |
842 | x->laddr->v4.sin_port; | |
d6c0256a XL |
843 | if (paddr->sa.sa_family == AF_INET6) |
844 | addr = jhash(&paddr->v6.sin6_addr, 16, seed); | |
845 | else | |
846 | addr = paddr->v4.sin_addr.s_addr; | |
847 | ||
848 | return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 | | |
849 | (__force __u32)lport, net_hash_mix(net), seed); | |
850 | } | |
851 | ||
852 | static const struct rhashtable_params sctp_hash_params = { | |
853 | .head_offset = offsetof(struct sctp_transport, node), | |
854 | .hashfn = sctp_hash_key, | |
855 | .obj_hashfn = sctp_hash_obj, | |
856 | .obj_cmpfn = sctp_hash_cmp, | |
857 | .automatic_shrinking = true, | |
858 | }; | |
859 | ||
860 | int sctp_transport_hashtable_init(void) | |
861 | { | |
862 | return rhashtable_init(&sctp_transport_hashtable, &sctp_hash_params); | |
863 | } | |
864 | ||
865 | void sctp_transport_hashtable_destroy(void) | |
866 | { | |
867 | rhashtable_destroy(&sctp_transport_hashtable); | |
868 | } | |
869 | ||
870 | void sctp_hash_transport(struct sctp_transport *t) | |
871 | { | |
d6c0256a XL |
872 | struct sctp_hash_cmp_arg arg; |
873 | ||
dd7445ad XL |
874 | if (t->asoc->temp) |
875 | return; | |
876 | ||
65a5124a | 877 | arg.ep = t->asoc->ep; |
d6c0256a XL |
878 | arg.paddr = &t->ipaddr; |
879 | arg.net = sock_net(t->asoc->base.sk); | |
880 | ||
881 | reinsert: | |
882 | if (rhashtable_lookup_insert_key(&sctp_transport_hashtable, &arg, | |
883 | &t->node, sctp_hash_params) == -EBUSY) | |
884 | goto reinsert; | |
885 | } | |
886 | ||
887 | void sctp_unhash_transport(struct sctp_transport *t) | |
888 | { | |
dd7445ad XL |
889 | if (t->asoc->temp) |
890 | return; | |
891 | ||
d6c0256a XL |
892 | rhashtable_remove_fast(&sctp_transport_hashtable, &t->node, |
893 | sctp_hash_params); | |
894 | } | |
895 | ||
896 | struct sctp_transport *sctp_addrs_lookup_transport( | |
897 | struct net *net, | |
898 | const union sctp_addr *laddr, | |
899 | const union sctp_addr *paddr) | |
900 | { | |
901 | struct sctp_hash_cmp_arg arg = { | |
65a5124a | 902 | .ep = NULL, |
d6c0256a XL |
903 | .laddr = laddr, |
904 | .paddr = paddr, | |
905 | .net = net, | |
906 | }; | |
907 | ||
908 | return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg, | |
909 | sctp_hash_params); | |
910 | } | |
911 | ||
912 | struct sctp_transport *sctp_epaddr_lookup_transport( | |
913 | const struct sctp_endpoint *ep, | |
914 | const union sctp_addr *paddr) | |
915 | { | |
d6c0256a | 916 | struct net *net = sock_net(ep->base.sk); |
65a5124a XL |
917 | struct sctp_hash_cmp_arg arg = { |
918 | .ep = ep, | |
919 | .paddr = paddr, | |
920 | .net = net, | |
921 | }; | |
d6c0256a | 922 | |
65a5124a XL |
923 | return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg, |
924 | sctp_hash_params); | |
d6c0256a XL |
925 | } |
926 | ||
1da177e4 LT |
927 | /* Look up an association. */ |
928 | static struct sctp_association *__sctp_lookup_association( | |
4110cc25 | 929 | struct net *net, |
1da177e4 LT |
930 | const union sctp_addr *local, |
931 | const union sctp_addr *peer, | |
932 | struct sctp_transport **pt) | |
933 | { | |
4f008781 | 934 | struct sctp_transport *t; |
1eed6779 | 935 | struct sctp_association *asoc = NULL; |
1da177e4 | 936 | |
4f008781 | 937 | t = sctp_addrs_lookup_transport(net, local, peer); |
1eed6779 XL |
938 | if (!t || !sctp_transport_hold(t)) |
939 | goto out; | |
1da177e4 | 940 | |
1eed6779 XL |
941 | asoc = t->asoc; |
942 | sctp_association_hold(asoc); | |
4f008781 | 943 | *pt = t; |
1da177e4 | 944 | |
1eed6779 XL |
945 | sctp_transport_put(t); |
946 | ||
947 | out: | |
1eed6779 | 948 | return asoc; |
1da177e4 LT |
949 | } |
950 | ||
4f008781 | 951 | /* Look up an association. protected by RCU read lock */ |
dda91928 | 952 | static |
4110cc25 EB |
953 | struct sctp_association *sctp_lookup_association(struct net *net, |
954 | const union sctp_addr *laddr, | |
1da177e4 | 955 | const union sctp_addr *paddr, |
dda91928 | 956 | struct sctp_transport **transportp) |
1da177e4 LT |
957 | { |
958 | struct sctp_association *asoc; | |
959 | ||
f46c7011 | 960 | rcu_read_lock(); |
4110cc25 | 961 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
f46c7011 | 962 | rcu_read_unlock(); |
1da177e4 LT |
963 | |
964 | return asoc; | |
965 | } | |
966 | ||
967 | /* Is there an association matching the given local and peer addresses? */ | |
4110cc25 EB |
968 | int sctp_has_association(struct net *net, |
969 | const union sctp_addr *laddr, | |
1da177e4 LT |
970 | const union sctp_addr *paddr) |
971 | { | |
972 | struct sctp_association *asoc; | |
973 | struct sctp_transport *transport; | |
974 | ||
4110cc25 | 975 | if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) { |
1da177e4 LT |
976 | sctp_association_put(asoc); |
977 | return 1; | |
978 | } | |
979 | ||
980 | return 0; | |
981 | } | |
982 | ||
983 | /* | |
984 | * SCTP Implementors Guide, 2.18 Handling of address | |
985 | * parameters within the INIT or INIT-ACK. | |
986 | * | |
987 | * D) When searching for a matching TCB upon reception of an INIT | |
988 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
989 | * source address of the packet (containing the INIT or | |
990 | * INIT-ACK) but the receiver SHOULD also use all valid | |
991 | * address parameters contained within the chunk. | |
992 | * | |
993 | * 2.18.3 Solution description | |
994 | * | |
995 | * This new text clearly specifies to an implementor the need | |
996 | * to look within the INIT or INIT-ACK. Any implementation that | |
997 | * does not do this, may not be able to establish associations | |
998 | * in certain circumstances. | |
999 | * | |
1000 | */ | |
4110cc25 EB |
1001 | static struct sctp_association *__sctp_rcv_init_lookup(struct net *net, |
1002 | struct sk_buff *skb, | |
1da177e4 LT |
1003 | const union sctp_addr *laddr, struct sctp_transport **transportp) |
1004 | { | |
1005 | struct sctp_association *asoc; | |
1006 | union sctp_addr addr; | |
1007 | union sctp_addr *paddr = &addr; | |
2c0fd387 | 1008 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
1009 | union sctp_params params; |
1010 | sctp_init_chunk_t *init; | |
1011 | struct sctp_transport *transport; | |
1012 | struct sctp_af *af; | |
1013 | ||
1da177e4 LT |
1014 | /* |
1015 | * This code will NOT touch anything inside the chunk--it is | |
1016 | * strictly READ-ONLY. | |
1017 | * | |
1018 | * RFC 2960 3 SCTP packet Format | |
1019 | * | |
1020 | * Multiple chunks can be bundled into one SCTP packet up to | |
1021 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
1022 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
1023 | * other chunk in a packet. See Section 6.10 for more details | |
1024 | * on chunk bundling. | |
1025 | */ | |
1026 | ||
1027 | /* Find the start of the TLVs and the end of the chunk. This is | |
1028 | * the region we search for address parameters. | |
1029 | */ | |
1030 | init = (sctp_init_chunk_t *)skb->data; | |
1031 | ||
1032 | /* Walk the parameters looking for embedded addresses. */ | |
1033 | sctp_walk_params(params, init, init_hdr.params) { | |
1034 | ||
1035 | /* Note: Ignoring hostname addresses. */ | |
1036 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
1037 | if (!af) | |
1038 | continue; | |
1039 | ||
dd86d136 | 1040 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 1041 | |
4110cc25 | 1042 | asoc = __sctp_lookup_association(net, laddr, paddr, &transport); |
1da177e4 LT |
1043 | if (asoc) |
1044 | return asoc; | |
1045 | } | |
1046 | ||
1047 | return NULL; | |
1048 | } | |
1049 | ||
df218577 VY |
1050 | /* ADD-IP, Section 5.2 |
1051 | * When an endpoint receives an ASCONF Chunk from the remote peer | |
1052 | * special procedures may be needed to identify the association the | |
1053 | * ASCONF Chunk is associated with. To properly find the association | |
1054 | * the following procedures SHOULD be followed: | |
1055 | * | |
1056 | * D2) If the association is not found, use the address found in the | |
1057 | * Address Parameter TLV combined with the port number found in the | |
1058 | * SCTP common header. If found proceed to rule D4. | |
1059 | * | |
1060 | * D2-ext) If more than one ASCONF Chunks are packed together, use the | |
1061 | * address found in the ASCONF Address Parameter TLV of each of the | |
1062 | * subsequent ASCONF Chunks. If found, proceed to rule D4. | |
1063 | */ | |
1064 | static struct sctp_association *__sctp_rcv_asconf_lookup( | |
4110cc25 | 1065 | struct net *net, |
df218577 VY |
1066 | sctp_chunkhdr_t *ch, |
1067 | const union sctp_addr *laddr, | |
bc92dd19 | 1068 | __be16 peer_port, |
df218577 VY |
1069 | struct sctp_transport **transportp) |
1070 | { | |
1071 | sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch; | |
1072 | struct sctp_af *af; | |
1073 | union sctp_addr_param *param; | |
1074 | union sctp_addr paddr; | |
1075 | ||
1076 | /* Skip over the ADDIP header and find the Address parameter */ | |
1077 | param = (union sctp_addr_param *)(asconf + 1); | |
1078 | ||
6a435732 | 1079 | af = sctp_get_af_specific(param_type2af(param->p.type)); |
df218577 VY |
1080 | if (unlikely(!af)) |
1081 | return NULL; | |
1082 | ||
1083 | af->from_addr_param(&paddr, param, peer_port, 0); | |
1084 | ||
4110cc25 | 1085 | return __sctp_lookup_association(net, laddr, &paddr, transportp); |
df218577 VY |
1086 | } |
1087 | ||
1088 | ||
bbd0d598 VY |
1089 | /* SCTP-AUTH, Section 6.3: |
1090 | * If the receiver does not find a STCB for a packet containing an AUTH | |
1091 | * chunk as the first chunk and not a COOKIE-ECHO chunk as the second | |
1092 | * chunk, it MUST use the chunks after the AUTH chunk to look up an existing | |
1093 | * association. | |
1094 | * | |
1095 | * This means that any chunks that can help us identify the association need | |
25985edc | 1096 | * to be looked at to find this association. |
bbd0d598 | 1097 | */ |
4110cc25 EB |
1098 | static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net, |
1099 | struct sk_buff *skb, | |
bbd0d598 VY |
1100 | const union sctp_addr *laddr, |
1101 | struct sctp_transport **transportp) | |
1102 | { | |
df218577 VY |
1103 | struct sctp_association *asoc = NULL; |
1104 | sctp_chunkhdr_t *ch; | |
1105 | int have_auth = 0; | |
1106 | unsigned int chunk_num = 1; | |
1107 | __u8 *ch_end; | |
1108 | ||
1109 | /* Walk through the chunks looking for AUTH or ASCONF chunks | |
1110 | * to help us find the association. | |
bbd0d598 | 1111 | */ |
df218577 VY |
1112 | ch = (sctp_chunkhdr_t *) skb->data; |
1113 | do { | |
1114 | /* Break out if chunk length is less then minimal. */ | |
1115 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
1116 | break; | |
1117 | ||
1118 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
1119 | if (ch_end > skb_tail_pointer(skb)) | |
1120 | break; | |
1121 | ||
cb3f837b | 1122 | switch (ch->type) { |
f7010e61 | 1123 | case SCTP_CID_AUTH: |
1124 | have_auth = chunk_num; | |
1125 | break; | |
1126 | ||
1127 | case SCTP_CID_COOKIE_ECHO: | |
1128 | /* If a packet arrives containing an AUTH chunk as | |
1129 | * a first chunk, a COOKIE-ECHO chunk as the second | |
1130 | * chunk, and possibly more chunks after them, and | |
1131 | * the receiver does not have an STCB for that | |
1132 | * packet, then authentication is based on | |
1133 | * the contents of the COOKIE- ECHO chunk. | |
1134 | */ | |
1135 | if (have_auth == 1 && chunk_num == 2) | |
1136 | return NULL; | |
1137 | break; | |
1138 | ||
1139 | case SCTP_CID_ASCONF: | |
1140 | if (have_auth || net->sctp.addip_noauth) | |
1141 | asoc = __sctp_rcv_asconf_lookup( | |
1142 | net, ch, laddr, | |
1143 | sctp_hdr(skb)->source, | |
1144 | transportp); | |
1145 | default: | |
1146 | break; | |
df218577 VY |
1147 | } |
1148 | ||
1149 | if (asoc) | |
1150 | break; | |
1151 | ||
1152 | ch = (sctp_chunkhdr_t *) ch_end; | |
1153 | chunk_num++; | |
1154 | } while (ch_end < skb_tail_pointer(skb)); | |
1155 | ||
1156 | return asoc; | |
bbd0d598 VY |
1157 | } |
1158 | ||
1159 | /* | |
1160 | * There are circumstances when we need to look inside the SCTP packet | |
1161 | * for information to help us find the association. Examples | |
1162 | * include looking inside of INIT/INIT-ACK chunks or after the AUTH | |
1163 | * chunks. | |
1164 | */ | |
4110cc25 EB |
1165 | static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net, |
1166 | struct sk_buff *skb, | |
bbd0d598 VY |
1167 | const union sctp_addr *laddr, |
1168 | struct sctp_transport **transportp) | |
1169 | { | |
1170 | sctp_chunkhdr_t *ch; | |
1171 | ||
90017acc MRL |
1172 | /* We do not allow GSO frames here as we need to linearize and |
1173 | * then cannot guarantee frame boundaries. This shouldn't be an | |
1174 | * issue as packets hitting this are mostly INIT or INIT-ACK and | |
1175 | * those cannot be on GSO-style anyway. | |
1176 | */ | |
1177 | if ((skb_shinfo(skb)->gso_type & SKB_GSO_SCTP) == SKB_GSO_SCTP) | |
1178 | return NULL; | |
1179 | ||
3acb50c1 MRL |
1180 | if (skb_linearize(skb)) |
1181 | return NULL; | |
1182 | ||
bbd0d598 VY |
1183 | ch = (sctp_chunkhdr_t *) skb->data; |
1184 | ||
df218577 VY |
1185 | /* The code below will attempt to walk the chunk and extract |
1186 | * parameter information. Before we do that, we need to verify | |
1187 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
1188 | * walk off the end. | |
1189 | */ | |
1190 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
1191 | return NULL; | |
1192 | ||
bbd0d598 | 1193 | /* If this is INIT/INIT-ACK look inside the chunk too. */ |
f482f2fc | 1194 | if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK) |
4110cc25 | 1195 | return __sctp_rcv_init_lookup(net, skb, laddr, transportp); |
bbd0d598 | 1196 | |
f482f2fc | 1197 | return __sctp_rcv_walk_lookup(net, skb, laddr, transportp); |
bbd0d598 VY |
1198 | } |
1199 | ||
1da177e4 | 1200 | /* Lookup an association for an inbound skb. */ |
4110cc25 EB |
1201 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
1202 | struct sk_buff *skb, | |
1da177e4 LT |
1203 | const union sctp_addr *paddr, |
1204 | const union sctp_addr *laddr, | |
1205 | struct sctp_transport **transportp) | |
1206 | { | |
1207 | struct sctp_association *asoc; | |
1208 | ||
4110cc25 | 1209 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
1da177e4 LT |
1210 | |
1211 | /* Further lookup for INIT/INIT-ACK packets. | |
1212 | * SCTP Implementors Guide, 2.18 Handling of address | |
1213 | * parameters within the INIT or INIT-ACK. | |
1214 | */ | |
1215 | if (!asoc) | |
4110cc25 | 1216 | asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp); |
1da177e4 LT |
1217 | |
1218 | return asoc; | |
1219 | } |