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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 | ||
79af02c2 DM |
93 | struct sctp_input_cb { |
94 | union { | |
95 | struct inet_skb_parm h4; | |
dfd56b8b | 96 | #if IS_ENABLED(CONFIG_IPV6) |
79af02c2 DM |
97 | struct inet6_skb_parm h6; |
98 | #endif | |
99 | } header; | |
100 | struct sctp_chunk *chunk; | |
101 | }; | |
102 | #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) | |
103 | ||
1da177e4 LT |
104 | /* |
105 | * This is the routine which IP calls when receiving an SCTP packet. | |
106 | */ | |
107 | int sctp_rcv(struct sk_buff *skb) | |
108 | { | |
109 | struct sock *sk; | |
110 | struct sctp_association *asoc; | |
111 | struct sctp_endpoint *ep = NULL; | |
112 | struct sctp_ep_common *rcvr; | |
113 | struct sctp_transport *transport = NULL; | |
114 | struct sctp_chunk *chunk; | |
1da177e4 LT |
115 | union sctp_addr src; |
116 | union sctp_addr dest; | |
117 | int family; | |
118 | struct sctp_af *af; | |
4cdadcbc | 119 | struct net *net = dev_net(skb->dev); |
1da177e4 | 120 | |
cb3f837b | 121 | if (skb->pkt_type != PACKET_HOST) |
1da177e4 LT |
122 | goto discard_it; |
123 | ||
08e3baef | 124 | __SCTP_INC_STATS(net, SCTP_MIB_INSCTPPACKS); |
1da177e4 | 125 | |
3acb50c1 MRL |
126 | /* If packet is too small to contain a single chunk, let's not |
127 | * waste time on it anymore. | |
128 | */ | |
129 | if (skb->len < sizeof(struct sctphdr) + sizeof(struct sctp_chunkhdr) + | |
130 | skb_transport_offset(skb)) | |
28cd7752 HX |
131 | goto discard_it; |
132 | ||
3acb50c1 MRL |
133 | if (!pskb_may_pull(skb, sizeof(struct sctphdr))) |
134 | goto discard_it; | |
1da177e4 | 135 | |
3acb50c1 | 136 | /* Pull up the IP header. */ |
ea2ae17d | 137 | __skb_pull(skb, skb_transport_offset(skb)); |
202863fe TH |
138 | |
139 | skb->csum_valid = 0; /* Previous value not applicable */ | |
140 | if (skb_csum_unnecessary(skb)) | |
141 | __skb_decr_checksum_unnecessary(skb); | |
142 | else if (!sctp_checksum_disable && sctp_rcv_checksum(net, skb) < 0) | |
1da177e4 | 143 | goto discard_it; |
202863fe | 144 | skb->csum_valid = 1; |
1da177e4 | 145 | |
3acb50c1 | 146 | __skb_pull(skb, sizeof(struct sctphdr)); |
1da177e4 | 147 | |
eddc9ec5 | 148 | family = ipver2af(ip_hdr(skb)->version); |
1da177e4 LT |
149 | af = sctp_get_af_specific(family); |
150 | if (unlikely(!af)) | |
151 | goto discard_it; | |
152 | ||
153 | /* Initialize local addresses for lookups. */ | |
154 | af->from_skb(&src, skb, 1); | |
155 | af->from_skb(&dest, skb, 0); | |
156 | ||
157 | /* If the packet is to or from a non-unicast address, | |
158 | * silently discard the packet. | |
159 | * | |
160 | * This is not clearly defined in the RFC except in section | |
161 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
162 | * Transmission Protocol" 2.1, "It is important to note that the | |
163 | * IP address of an SCTP transport address must be a routable | |
164 | * unicast address. In other words, IP multicast addresses and | |
165 | * IP broadcast addresses cannot be used in an SCTP transport | |
166 | * address." | |
167 | */ | |
5636bef7 VY |
168 | if (!af->addr_valid(&src, NULL, skb) || |
169 | !af->addr_valid(&dest, NULL, skb)) | |
1da177e4 LT |
170 | goto discard_it; |
171 | ||
4110cc25 | 172 | asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport); |
1c7d1fc1 | 173 | |
0fd9a65a | 174 | if (!asoc) |
4cdadcbc | 175 | ep = __sctp_rcv_lookup_endpoint(net, &dest); |
0fd9a65a NH |
176 | |
177 | /* Retrieve the common input handling substructure. */ | |
178 | rcvr = asoc ? &asoc->base : &ep->base; | |
179 | sk = rcvr->sk; | |
180 | ||
181 | /* | |
182 | * If a frame arrives on an interface and the receiving socket is | |
183 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
184 | */ | |
8d72651d | 185 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) { |
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)) { |
08e3baef | 209 | __SCTP_INC_STATS(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. */ | |
cea8768f | 222 | chunk = sctp_chunkify(skb, asoc, sk, GFP_ATOMIC); |
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. */ | |
3acb50c1 | 231 | chunk->sctp_hdr = sctp_hdr(skb); |
1da177e4 LT |
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 | */ | |
5bc1d1b4 | 243 | bh_lock_sock(sk); |
1da177e4 | 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 | */ | |
5bc1d1b4 | 253 | bh_unlock_sock(sk); |
ae53b5bd | 254 | sk = rcvr->sk; |
5bc1d1b4 | 255 | bh_lock_sock(sk); |
ae53b5bd VY |
256 | } |
257 | ||
ac0b0462 | 258 | if (sock_owned_by_user(sk)) { |
50b1a782 | 259 | if (sctp_add_backlog(sk, skb)) { |
5bc1d1b4 | 260 | bh_unlock_sock(sk); |
50b1a782 ZY |
261 | sctp_chunk_free(chunk); |
262 | skb = NULL; /* sctp_chunk_free already freed the skb */ | |
263 | goto discard_release; | |
264 | } | |
08e3baef | 265 | __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_BACKLOG); |
ac0b0462 | 266 | } else { |
08e3baef | 267 | __SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_SOFTIRQ); |
61c9fed4 | 268 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 269 | } |
1da177e4 | 270 | |
5bc1d1b4 | 271 | 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: | |
08e3baef | 282 | __SCTP_INC_STATS(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; | |
5bc1d1b4 | 332 | bh_lock_sock(sk); |
61c9fed4 VY |
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 | ||
5bc1d1b4 | 342 | bh_unlock_sock(sk); |
61c9fed4 VY |
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 | 526 | |
5bc1d1b4 | 527 | bh_lock_sock(sk); |
1da177e4 LT |
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)) | |
02a1d6e7 | 533 | __NET_INC_STATS(net, LINUX_MIB_LOCKDROPPEDICMPS); |
1da177e4 | 534 | |
1da177e4 LT |
535 | *app = asoc; |
536 | *tpp = transport; | |
537 | return sk; | |
538 | ||
539 | out: | |
e4772668 | 540 | sctp_association_put(asoc); |
1da177e4 LT |
541 | return NULL; |
542 | } | |
543 | ||
544 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 545 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 | 546 | { |
5bc1d1b4 | 547 | bh_unlock_sock(sk); |
e4772668 | 548 | sctp_association_put(asoc); |
1da177e4 LT |
549 | } |
550 | ||
551 | /* | |
552 | * This routine is called by the ICMP module when it gets some | |
553 | * sort of error condition. If err < 0 then the socket should | |
554 | * be closed and the error returned to the user. If err > 0 | |
555 | * it's just the icmp type << 8 | icmp code. After adjustment | |
556 | * header points to the first 8 bytes of the sctp header. We need | |
557 | * to find the appropriate port. | |
558 | * | |
559 | * The locking strategy used here is very "optimistic". When | |
560 | * someone else accesses the socket the ICMP is just dropped | |
561 | * and for some paths there is no check at all. | |
562 | * A more general error queue to queue errors for later handling | |
563 | * is probably better. | |
564 | * | |
565 | */ | |
566 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
567 | { | |
b71d1d42 | 568 | const struct iphdr *iph = (const struct iphdr *)skb->data; |
a27ef749 | 569 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
570 | const int type = icmp_hdr(skb)->type; |
571 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 572 | struct sock *sk; |
8de8c873 | 573 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
574 | struct sctp_transport *transport; |
575 | struct inet_sock *inet; | |
aef6de51 | 576 | __u16 saveip, savesctp; |
1da177e4 | 577 | int err; |
4110cc25 | 578 | struct net *net = dev_net(skb->dev); |
1da177e4 | 579 | |
1da177e4 | 580 | /* Fix up skb to look at the embedded net header. */ |
b0e380b1 ACM |
581 | saveip = skb->network_header; |
582 | savesctp = skb->transport_header; | |
31c7711b | 583 | skb_reset_network_header(skb); |
a27ef749 | 584 | skb_set_transport_header(skb, ihlen); |
4110cc25 | 585 | sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport); |
2e07fa9c | 586 | /* Put back, the original values. */ |
b0e380b1 ACM |
587 | skb->network_header = saveip; |
588 | skb->transport_header = savesctp; | |
1da177e4 | 589 | if (!sk) { |
5d3848bc | 590 | __ICMP_INC_STATS(net, ICMP_MIB_INERRORS); |
1da177e4 LT |
591 | return; |
592 | } | |
593 | /* Warning: The sock lock is held. Remember to call | |
594 | * sctp_err_finish! | |
595 | */ | |
596 | ||
597 | switch (type) { | |
598 | case ICMP_PARAMETERPROB: | |
599 | err = EPROTO; | |
600 | break; | |
601 | case ICMP_DEST_UNREACH: | |
602 | if (code > NR_ICMP_UNREACH) | |
603 | goto out_unlock; | |
604 | ||
605 | /* PMTU discovery (RFC1191) */ | |
606 | if (ICMP_FRAG_NEEDED == code) { | |
3822a5ff MRL |
607 | sctp_icmp_frag_needed(sk, asoc, transport, |
608 | WORD_TRUNC(info)); | |
1da177e4 | 609 | goto out_unlock; |
8d72651d | 610 | } else { |
1da177e4 | 611 | if (ICMP_PROT_UNREACH == code) { |
d1ad1ff2 | 612 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
613 | transport); |
614 | goto out_unlock; | |
615 | } | |
616 | } | |
617 | err = icmp_err_convert[code].errno; | |
618 | break; | |
619 | case ICMP_TIME_EXCEEDED: | |
620 | /* Ignore any time exceeded errors due to fragment reassembly | |
621 | * timeouts. | |
622 | */ | |
623 | if (ICMP_EXC_FRAGTIME == code) | |
624 | goto out_unlock; | |
625 | ||
626 | err = EHOSTUNREACH; | |
627 | break; | |
55be7a9c DM |
628 | case ICMP_REDIRECT: |
629 | sctp_icmp_redirect(sk, transport, skb); | |
3f96a532 | 630 | /* Fall through to out_unlock. */ |
1da177e4 LT |
631 | default: |
632 | goto out_unlock; | |
633 | } | |
634 | ||
635 | inet = inet_sk(sk); | |
636 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
637 | sk->sk_err = err; | |
638 | sk->sk_error_report(sk); | |
639 | } else { /* Only an error on timeout */ | |
640 | sk->sk_err_soft = err; | |
641 | } | |
642 | ||
643 | out_unlock: | |
d1ad1ff2 | 644 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
645 | } |
646 | ||
647 | /* | |
648 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
649 | * | |
650 | * This function scans all the chunks in the OOTB packet to determine if | |
651 | * the packet should be discarded right away. If a response might be needed | |
652 | * for this packet, or, if further processing is possible, the packet will | |
653 | * be queued to a proper inqueue for the next phase of handling. | |
654 | * | |
655 | * Output: | |
656 | * Return 0 - If further processing is needed. | |
657 | * Return 1 - If the packet can be discarded right away. | |
658 | */ | |
04675210 | 659 | static int sctp_rcv_ootb(struct sk_buff *skb) |
1da177e4 | 660 | { |
3acb50c1 MRL |
661 | sctp_chunkhdr_t *ch, _ch; |
662 | int ch_end, offset = 0; | |
1da177e4 LT |
663 | |
664 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 | 665 | do { |
3acb50c1 MRL |
666 | /* Make sure we have at least the header there */ |
667 | if (offset + sizeof(sctp_chunkhdr_t) > skb->len) | |
668 | break; | |
669 | ||
670 | ch = skb_header_pointer(skb, offset, sizeof(*ch), &_ch); | |
671 | ||
a7d1f1b6 TF |
672 | /* Break out if chunk length is less then minimal. */ |
673 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
674 | break; | |
675 | ||
3acb50c1 MRL |
676 | ch_end = offset + WORD_ROUND(ntohs(ch->length)); |
677 | if (ch_end > skb->len) | |
a7d1f1b6 | 678 | break; |
1da177e4 LT |
679 | |
680 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
681 | * receiver MUST silently discard the OOTB packet and take no | |
682 | * further action. | |
683 | */ | |
684 | if (SCTP_CID_ABORT == ch->type) | |
685 | goto discard; | |
686 | ||
687 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
688 | * chunk, the receiver should silently discard the packet | |
689 | * and take no further action. | |
690 | */ | |
691 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
692 | goto discard; | |
693 | ||
3c77f961 VY |
694 | /* RFC 4460, 2.11.2 |
695 | * This will discard packets with INIT chunk bundled as | |
696 | * subsequent chunks in the packet. When INIT is first, | |
697 | * the normal INIT processing will discard the chunk. | |
698 | */ | |
699 | if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data) | |
700 | goto discard; | |
701 | ||
3acb50c1 MRL |
702 | offset = ch_end; |
703 | } while (ch_end < skb->len); | |
1da177e4 LT |
704 | |
705 | return 0; | |
706 | ||
707 | discard: | |
708 | return 1; | |
709 | } | |
710 | ||
711 | /* Insert endpoint into the hash table. */ | |
712 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
713 | { | |
4cdadcbc | 714 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
715 | struct sctp_ep_common *epb; |
716 | struct sctp_hashbucket *head; | |
717 | ||
718 | epb = &ep->base; | |
719 | ||
4cdadcbc | 720 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
721 | head = &sctp_ep_hashtable[epb->hashent]; |
722 | ||
387602df | 723 | write_lock(&head->lock); |
d970dbf8 | 724 | hlist_add_head(&epb->node, &head->chain); |
387602df | 725 | write_unlock(&head->lock); |
1da177e4 LT |
726 | } |
727 | ||
728 | /* Add an endpoint to the hash. Local BH-safe. */ | |
729 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
730 | { | |
79b91130 | 731 | local_bh_disable(); |
1da177e4 | 732 | __sctp_hash_endpoint(ep); |
79b91130 | 733 | local_bh_enable(); |
1da177e4 LT |
734 | } |
735 | ||
736 | /* Remove endpoint from the hash table. */ | |
737 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
738 | { | |
4cdadcbc | 739 | struct net *net = sock_net(ep->base.sk); |
1da177e4 LT |
740 | struct sctp_hashbucket *head; |
741 | struct sctp_ep_common *epb; | |
742 | ||
743 | epb = &ep->base; | |
744 | ||
4cdadcbc | 745 | epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port); |
1da177e4 LT |
746 | |
747 | head = &sctp_ep_hashtable[epb->hashent]; | |
748 | ||
387602df | 749 | write_lock(&head->lock); |
2eebc1e1 | 750 | hlist_del_init(&epb->node); |
387602df | 751 | write_unlock(&head->lock); |
1da177e4 LT |
752 | } |
753 | ||
754 | /* Remove endpoint from the hash. Local BH-safe. */ | |
755 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
756 | { | |
79b91130 | 757 | local_bh_disable(); |
1da177e4 | 758 | __sctp_unhash_endpoint(ep); |
79b91130 | 759 | local_bh_enable(); |
1da177e4 LT |
760 | } |
761 | ||
762 | /* Look up an endpoint. */ | |
4cdadcbc EB |
763 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net, |
764 | const union sctp_addr *laddr) | |
1da177e4 LT |
765 | { |
766 | struct sctp_hashbucket *head; | |
767 | struct sctp_ep_common *epb; | |
768 | struct sctp_endpoint *ep; | |
769 | int hash; | |
770 | ||
4cdadcbc | 771 | hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
772 | head = &sctp_ep_hashtable[hash]; |
773 | read_lock(&head->lock); | |
b67bfe0d | 774 | sctp_for_each_hentry(epb, &head->chain) { |
1da177e4 | 775 | ep = sctp_ep(epb); |
4cdadcbc | 776 | if (sctp_endpoint_is_match(ep, net, laddr)) |
1da177e4 LT |
777 | goto hit; |
778 | } | |
779 | ||
2ce95503 | 780 | ep = sctp_sk(net->sctp.ctl_sock)->ep; |
1da177e4 LT |
781 | |
782 | hit: | |
783 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
784 | read_unlock(&head->lock); |
785 | return ep; | |
786 | } | |
787 | ||
d6c0256a XL |
788 | /* rhashtable for transport */ |
789 | struct sctp_hash_cmp_arg { | |
65a5124a | 790 | const struct sctp_endpoint *ep; |
d6c0256a XL |
791 | const union sctp_addr *laddr; |
792 | const union sctp_addr *paddr; | |
793 | const struct net *net; | |
794 | }; | |
795 | ||
796 | static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg, | |
797 | const void *ptr) | |
798 | { | |
799 | const struct sctp_hash_cmp_arg *x = arg->key; | |
800 | const struct sctp_transport *t = ptr; | |
801 | struct sctp_association *asoc = t->asoc; | |
802 | const struct net *net = x->net; | |
803 | ||
d6c0256a XL |
804 | if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr)) |
805 | return 1; | |
806 | if (!net_eq(sock_net(asoc->base.sk), net)) | |
807 | return 1; | |
65a5124a XL |
808 | if (x->ep) { |
809 | if (x->ep != asoc->ep) | |
810 | return 1; | |
811 | } else { | |
812 | if (x->laddr->v4.sin_port != htons(asoc->base.bind_addr.port)) | |
813 | return 1; | |
814 | if (!sctp_bind_addr_match(&asoc->base.bind_addr, | |
815 | x->laddr, sctp_sk(asoc->base.sk))) | |
816 | return 1; | |
817 | } | |
d6c0256a XL |
818 | |
819 | return 0; | |
820 | } | |
821 | ||
822 | static inline u32 sctp_hash_obj(const void *data, u32 len, u32 seed) | |
823 | { | |
824 | const struct sctp_transport *t = data; | |
825 | const union sctp_addr *paddr = &t->ipaddr; | |
826 | const struct net *net = sock_net(t->asoc->base.sk); | |
827 | u16 lport = htons(t->asoc->base.bind_addr.port); | |
828 | u32 addr; | |
829 | ||
830 | if (paddr->sa.sa_family == AF_INET6) | |
831 | addr = jhash(&paddr->v6.sin6_addr, 16, seed); | |
832 | else | |
833 | addr = paddr->v4.sin_addr.s_addr; | |
834 | ||
835 | return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 | | |
836 | (__force __u32)lport, net_hash_mix(net), seed); | |
837 | } | |
838 | ||
839 | static inline u32 sctp_hash_key(const void *data, u32 len, u32 seed) | |
840 | { | |
841 | const struct sctp_hash_cmp_arg *x = data; | |
842 | const union sctp_addr *paddr = x->paddr; | |
843 | const struct net *net = x->net; | |
65a5124a | 844 | u16 lport; |
d6c0256a XL |
845 | u32 addr; |
846 | ||
65a5124a XL |
847 | lport = x->ep ? htons(x->ep->base.bind_addr.port) : |
848 | x->laddr->v4.sin_port; | |
d6c0256a XL |
849 | if (paddr->sa.sa_family == AF_INET6) |
850 | addr = jhash(&paddr->v6.sin6_addr, 16, seed); | |
851 | else | |
852 | addr = paddr->v4.sin_addr.s_addr; | |
853 | ||
854 | return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 | | |
855 | (__force __u32)lport, net_hash_mix(net), seed); | |
856 | } | |
857 | ||
858 | static const struct rhashtable_params sctp_hash_params = { | |
859 | .head_offset = offsetof(struct sctp_transport, node), | |
860 | .hashfn = sctp_hash_key, | |
861 | .obj_hashfn = sctp_hash_obj, | |
862 | .obj_cmpfn = sctp_hash_cmp, | |
863 | .automatic_shrinking = true, | |
864 | }; | |
865 | ||
866 | int sctp_transport_hashtable_init(void) | |
867 | { | |
868 | return rhashtable_init(&sctp_transport_hashtable, &sctp_hash_params); | |
869 | } | |
870 | ||
871 | void sctp_transport_hashtable_destroy(void) | |
872 | { | |
873 | rhashtable_destroy(&sctp_transport_hashtable); | |
874 | } | |
875 | ||
876 | void sctp_hash_transport(struct sctp_transport *t) | |
877 | { | |
d6c0256a XL |
878 | struct sctp_hash_cmp_arg arg; |
879 | ||
dd7445ad XL |
880 | if (t->asoc->temp) |
881 | return; | |
882 | ||
65a5124a | 883 | arg.ep = t->asoc->ep; |
d6c0256a XL |
884 | arg.paddr = &t->ipaddr; |
885 | arg.net = sock_net(t->asoc->base.sk); | |
886 | ||
887 | reinsert: | |
888 | if (rhashtable_lookup_insert_key(&sctp_transport_hashtable, &arg, | |
889 | &t->node, sctp_hash_params) == -EBUSY) | |
890 | goto reinsert; | |
891 | } | |
892 | ||
893 | void sctp_unhash_transport(struct sctp_transport *t) | |
894 | { | |
dd7445ad XL |
895 | if (t->asoc->temp) |
896 | return; | |
897 | ||
d6c0256a XL |
898 | rhashtable_remove_fast(&sctp_transport_hashtable, &t->node, |
899 | sctp_hash_params); | |
900 | } | |
901 | ||
902 | struct sctp_transport *sctp_addrs_lookup_transport( | |
903 | struct net *net, | |
904 | const union sctp_addr *laddr, | |
905 | const union sctp_addr *paddr) | |
906 | { | |
907 | struct sctp_hash_cmp_arg arg = { | |
65a5124a | 908 | .ep = NULL, |
d6c0256a XL |
909 | .laddr = laddr, |
910 | .paddr = paddr, | |
911 | .net = net, | |
912 | }; | |
913 | ||
914 | return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg, | |
915 | sctp_hash_params); | |
916 | } | |
917 | ||
918 | struct sctp_transport *sctp_epaddr_lookup_transport( | |
919 | const struct sctp_endpoint *ep, | |
920 | const union sctp_addr *paddr) | |
921 | { | |
d6c0256a | 922 | struct net *net = sock_net(ep->base.sk); |
65a5124a XL |
923 | struct sctp_hash_cmp_arg arg = { |
924 | .ep = ep, | |
925 | .paddr = paddr, | |
926 | .net = net, | |
927 | }; | |
d6c0256a | 928 | |
65a5124a XL |
929 | return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg, |
930 | sctp_hash_params); | |
d6c0256a XL |
931 | } |
932 | ||
1da177e4 LT |
933 | /* Look up an association. */ |
934 | static struct sctp_association *__sctp_lookup_association( | |
4110cc25 | 935 | struct net *net, |
1da177e4 LT |
936 | const union sctp_addr *local, |
937 | const union sctp_addr *peer, | |
938 | struct sctp_transport **pt) | |
939 | { | |
4f008781 | 940 | struct sctp_transport *t; |
1eed6779 | 941 | struct sctp_association *asoc = NULL; |
1da177e4 | 942 | |
4f008781 | 943 | t = sctp_addrs_lookup_transport(net, local, peer); |
1eed6779 XL |
944 | if (!t || !sctp_transport_hold(t)) |
945 | goto out; | |
1da177e4 | 946 | |
1eed6779 XL |
947 | asoc = t->asoc; |
948 | sctp_association_hold(asoc); | |
4f008781 | 949 | *pt = t; |
1da177e4 | 950 | |
1eed6779 XL |
951 | sctp_transport_put(t); |
952 | ||
953 | out: | |
1eed6779 | 954 | return asoc; |
1da177e4 LT |
955 | } |
956 | ||
4f008781 | 957 | /* Look up an association. protected by RCU read lock */ |
dda91928 | 958 | static |
4110cc25 EB |
959 | struct sctp_association *sctp_lookup_association(struct net *net, |
960 | const union sctp_addr *laddr, | |
1da177e4 | 961 | const union sctp_addr *paddr, |
dda91928 | 962 | struct sctp_transport **transportp) |
1da177e4 LT |
963 | { |
964 | struct sctp_association *asoc; | |
965 | ||
f46c7011 | 966 | rcu_read_lock(); |
4110cc25 | 967 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
f46c7011 | 968 | rcu_read_unlock(); |
1da177e4 LT |
969 | |
970 | return asoc; | |
971 | } | |
972 | ||
973 | /* Is there an association matching the given local and peer addresses? */ | |
4110cc25 EB |
974 | int sctp_has_association(struct net *net, |
975 | const union sctp_addr *laddr, | |
1da177e4 LT |
976 | const union sctp_addr *paddr) |
977 | { | |
978 | struct sctp_association *asoc; | |
979 | struct sctp_transport *transport; | |
980 | ||
4110cc25 | 981 | if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) { |
1da177e4 LT |
982 | sctp_association_put(asoc); |
983 | return 1; | |
984 | } | |
985 | ||
986 | return 0; | |
987 | } | |
988 | ||
989 | /* | |
990 | * SCTP Implementors Guide, 2.18 Handling of address | |
991 | * parameters within the INIT or INIT-ACK. | |
992 | * | |
993 | * D) When searching for a matching TCB upon reception of an INIT | |
994 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
995 | * source address of the packet (containing the INIT or | |
996 | * INIT-ACK) but the receiver SHOULD also use all valid | |
997 | * address parameters contained within the chunk. | |
998 | * | |
999 | * 2.18.3 Solution description | |
1000 | * | |
1001 | * This new text clearly specifies to an implementor the need | |
1002 | * to look within the INIT or INIT-ACK. Any implementation that | |
1003 | * does not do this, may not be able to establish associations | |
1004 | * in certain circumstances. | |
1005 | * | |
1006 | */ | |
4110cc25 EB |
1007 | static struct sctp_association *__sctp_rcv_init_lookup(struct net *net, |
1008 | struct sk_buff *skb, | |
1da177e4 LT |
1009 | const union sctp_addr *laddr, struct sctp_transport **transportp) |
1010 | { | |
1011 | struct sctp_association *asoc; | |
1012 | union sctp_addr addr; | |
1013 | union sctp_addr *paddr = &addr; | |
2c0fd387 | 1014 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
1015 | union sctp_params params; |
1016 | sctp_init_chunk_t *init; | |
1017 | struct sctp_transport *transport; | |
1018 | struct sctp_af *af; | |
1019 | ||
1da177e4 LT |
1020 | /* |
1021 | * This code will NOT touch anything inside the chunk--it is | |
1022 | * strictly READ-ONLY. | |
1023 | * | |
1024 | * RFC 2960 3 SCTP packet Format | |
1025 | * | |
1026 | * Multiple chunks can be bundled into one SCTP packet up to | |
1027 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
1028 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
1029 | * other chunk in a packet. See Section 6.10 for more details | |
1030 | * on chunk bundling. | |
1031 | */ | |
1032 | ||
1033 | /* Find the start of the TLVs and the end of the chunk. This is | |
1034 | * the region we search for address parameters. | |
1035 | */ | |
1036 | init = (sctp_init_chunk_t *)skb->data; | |
1037 | ||
1038 | /* Walk the parameters looking for embedded addresses. */ | |
1039 | sctp_walk_params(params, init, init_hdr.params) { | |
1040 | ||
1041 | /* Note: Ignoring hostname addresses. */ | |
1042 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
1043 | if (!af) | |
1044 | continue; | |
1045 | ||
dd86d136 | 1046 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 1047 | |
4110cc25 | 1048 | asoc = __sctp_lookup_association(net, laddr, paddr, &transport); |
1da177e4 LT |
1049 | if (asoc) |
1050 | return asoc; | |
1051 | } | |
1052 | ||
1053 | return NULL; | |
1054 | } | |
1055 | ||
df218577 VY |
1056 | /* ADD-IP, Section 5.2 |
1057 | * When an endpoint receives an ASCONF Chunk from the remote peer | |
1058 | * special procedures may be needed to identify the association the | |
1059 | * ASCONF Chunk is associated with. To properly find the association | |
1060 | * the following procedures SHOULD be followed: | |
1061 | * | |
1062 | * D2) If the association is not found, use the address found in the | |
1063 | * Address Parameter TLV combined with the port number found in the | |
1064 | * SCTP common header. If found proceed to rule D4. | |
1065 | * | |
1066 | * D2-ext) If more than one ASCONF Chunks are packed together, use the | |
1067 | * address found in the ASCONF Address Parameter TLV of each of the | |
1068 | * subsequent ASCONF Chunks. If found, proceed to rule D4. | |
1069 | */ | |
1070 | static struct sctp_association *__sctp_rcv_asconf_lookup( | |
4110cc25 | 1071 | struct net *net, |
df218577 VY |
1072 | sctp_chunkhdr_t *ch, |
1073 | const union sctp_addr *laddr, | |
bc92dd19 | 1074 | __be16 peer_port, |
df218577 VY |
1075 | struct sctp_transport **transportp) |
1076 | { | |
1077 | sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch; | |
1078 | struct sctp_af *af; | |
1079 | union sctp_addr_param *param; | |
1080 | union sctp_addr paddr; | |
1081 | ||
1082 | /* Skip over the ADDIP header and find the Address parameter */ | |
1083 | param = (union sctp_addr_param *)(asconf + 1); | |
1084 | ||
6a435732 | 1085 | af = sctp_get_af_specific(param_type2af(param->p.type)); |
df218577 VY |
1086 | if (unlikely(!af)) |
1087 | return NULL; | |
1088 | ||
1089 | af->from_addr_param(&paddr, param, peer_port, 0); | |
1090 | ||
4110cc25 | 1091 | return __sctp_lookup_association(net, laddr, &paddr, transportp); |
df218577 VY |
1092 | } |
1093 | ||
1094 | ||
bbd0d598 VY |
1095 | /* SCTP-AUTH, Section 6.3: |
1096 | * If the receiver does not find a STCB for a packet containing an AUTH | |
1097 | * chunk as the first chunk and not a COOKIE-ECHO chunk as the second | |
1098 | * chunk, it MUST use the chunks after the AUTH chunk to look up an existing | |
1099 | * association. | |
1100 | * | |
1101 | * This means that any chunks that can help us identify the association need | |
25985edc | 1102 | * to be looked at to find this association. |
bbd0d598 | 1103 | */ |
4110cc25 EB |
1104 | static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net, |
1105 | struct sk_buff *skb, | |
bbd0d598 VY |
1106 | const union sctp_addr *laddr, |
1107 | struct sctp_transport **transportp) | |
1108 | { | |
df218577 VY |
1109 | struct sctp_association *asoc = NULL; |
1110 | sctp_chunkhdr_t *ch; | |
1111 | int have_auth = 0; | |
1112 | unsigned int chunk_num = 1; | |
1113 | __u8 *ch_end; | |
1114 | ||
1115 | /* Walk through the chunks looking for AUTH or ASCONF chunks | |
1116 | * to help us find the association. | |
bbd0d598 | 1117 | */ |
df218577 VY |
1118 | ch = (sctp_chunkhdr_t *) skb->data; |
1119 | do { | |
1120 | /* Break out if chunk length is less then minimal. */ | |
1121 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
1122 | break; | |
1123 | ||
1124 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
1125 | if (ch_end > skb_tail_pointer(skb)) | |
1126 | break; | |
1127 | ||
cb3f837b | 1128 | switch (ch->type) { |
f7010e61 | 1129 | case SCTP_CID_AUTH: |
1130 | have_auth = chunk_num; | |
1131 | break; | |
1132 | ||
1133 | case SCTP_CID_COOKIE_ECHO: | |
1134 | /* If a packet arrives containing an AUTH chunk as | |
1135 | * a first chunk, a COOKIE-ECHO chunk as the second | |
1136 | * chunk, and possibly more chunks after them, and | |
1137 | * the receiver does not have an STCB for that | |
1138 | * packet, then authentication is based on | |
1139 | * the contents of the COOKIE- ECHO chunk. | |
1140 | */ | |
1141 | if (have_auth == 1 && chunk_num == 2) | |
1142 | return NULL; | |
1143 | break; | |
1144 | ||
1145 | case SCTP_CID_ASCONF: | |
1146 | if (have_auth || net->sctp.addip_noauth) | |
1147 | asoc = __sctp_rcv_asconf_lookup( | |
1148 | net, ch, laddr, | |
1149 | sctp_hdr(skb)->source, | |
1150 | transportp); | |
1151 | default: | |
1152 | break; | |
df218577 VY |
1153 | } |
1154 | ||
1155 | if (asoc) | |
1156 | break; | |
1157 | ||
1158 | ch = (sctp_chunkhdr_t *) ch_end; | |
1159 | chunk_num++; | |
1160 | } while (ch_end < skb_tail_pointer(skb)); | |
1161 | ||
1162 | return asoc; | |
bbd0d598 VY |
1163 | } |
1164 | ||
1165 | /* | |
1166 | * There are circumstances when we need to look inside the SCTP packet | |
1167 | * for information to help us find the association. Examples | |
1168 | * include looking inside of INIT/INIT-ACK chunks or after the AUTH | |
1169 | * chunks. | |
1170 | */ | |
4110cc25 EB |
1171 | static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net, |
1172 | struct sk_buff *skb, | |
bbd0d598 VY |
1173 | const union sctp_addr *laddr, |
1174 | struct sctp_transport **transportp) | |
1175 | { | |
1176 | sctp_chunkhdr_t *ch; | |
1177 | ||
3acb50c1 MRL |
1178 | if (skb_linearize(skb)) |
1179 | return NULL; | |
1180 | ||
bbd0d598 VY |
1181 | ch = (sctp_chunkhdr_t *) skb->data; |
1182 | ||
df218577 VY |
1183 | /* The code below will attempt to walk the chunk and extract |
1184 | * parameter information. Before we do that, we need to verify | |
1185 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
1186 | * walk off the end. | |
1187 | */ | |
1188 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
1189 | return NULL; | |
1190 | ||
bbd0d598 | 1191 | /* If this is INIT/INIT-ACK look inside the chunk too. */ |
f482f2fc | 1192 | if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK) |
4110cc25 | 1193 | return __sctp_rcv_init_lookup(net, skb, laddr, transportp); |
bbd0d598 | 1194 | |
f482f2fc | 1195 | return __sctp_rcv_walk_lookup(net, skb, laddr, transportp); |
bbd0d598 VY |
1196 | } |
1197 | ||
1da177e4 | 1198 | /* Lookup an association for an inbound skb. */ |
4110cc25 EB |
1199 | static struct sctp_association *__sctp_rcv_lookup(struct net *net, |
1200 | struct sk_buff *skb, | |
1da177e4 LT |
1201 | const union sctp_addr *paddr, |
1202 | const union sctp_addr *laddr, | |
1203 | struct sctp_transport **transportp) | |
1204 | { | |
1205 | struct sctp_association *asoc; | |
1206 | ||
4110cc25 | 1207 | asoc = __sctp_lookup_association(net, laddr, paddr, transportp); |
1da177e4 LT |
1208 | |
1209 | /* Further lookup for INIT/INIT-ACK packets. | |
1210 | * SCTP Implementors Guide, 2.18 Handling of address | |
1211 | * parameters within the INIT or INIT-ACK. | |
1212 | */ | |
1213 | if (!asoc) | |
4110cc25 | 1214 | asoc = __sctp_rcv_lookup_harder(net, skb, laddr, transportp); |
1da177e4 LT |
1215 | |
1216 | return asoc; | |
1217 | } |