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1da177e4 LT |
1 | /* SCTP kernel reference Implementation |
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 | * | |
9 | * This file is part of the SCTP kernel reference Implementation | |
10 | * | |
11 | * These functions handle all input from the IP layer into SCTP. | |
12 | * | |
13 | * The SCTP reference implementation is free software; | |
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 | * | |
19 | * The SCTP reference implementation is distributed in the hope that it | |
20 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied | |
21 | * ************************ | |
22 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
23 | * See the GNU General Public License for more details. | |
24 | * | |
25 | * You should have received a copy of the GNU General Public License | |
26 | * along with GNU CC; see the file COPYING. If not, write to | |
27 | * the Free Software Foundation, 59 Temple Place - Suite 330, | |
28 | * Boston, MA 02111-1307, USA. | |
29 | * | |
30 | * Please send any bug reports or fixes you make to the | |
31 | * email address(es): | |
32 | * lksctp developers <lksctp-developers@lists.sourceforge.net> | |
33 | * | |
34 | * Or submit a bug report through the following website: | |
35 | * http://www.sf.net/projects/lksctp | |
36 | * | |
37 | * Written or modified by: | |
38 | * La Monte H.P. Yarroll <piggy@acm.org> | |
39 | * Karl Knutson <karl@athena.chicago.il.us> | |
40 | * Xingang Guo <xingang.guo@intel.com> | |
41 | * Jon Grimm <jgrimm@us.ibm.com> | |
42 | * Hui Huang <hui.huang@nokia.com> | |
43 | * Daisy Chang <daisyc@us.ibm.com> | |
44 | * Sridhar Samudrala <sri@us.ibm.com> | |
45 | * Ardelle Fan <ardelle.fan@intel.com> | |
46 | * | |
47 | * Any bugs reported given to us we will try to fix... any fixes shared will | |
48 | * be incorporated into the next SCTP release. | |
49 | */ | |
50 | ||
51 | #include <linux/types.h> | |
52 | #include <linux/list.h> /* For struct list_head */ | |
53 | #include <linux/socket.h> | |
54 | #include <linux/ip.h> | |
55 | #include <linux/time.h> /* For struct timeval */ | |
56 | #include <net/ip.h> | |
57 | #include <net/icmp.h> | |
58 | #include <net/snmp.h> | |
59 | #include <net/sock.h> | |
60 | #include <net/xfrm.h> | |
61 | #include <net/sctp/sctp.h> | |
62 | #include <net/sctp/sm.h> | |
63 | ||
64 | /* Forward declarations for internal helpers. */ | |
65 | static int sctp_rcv_ootb(struct sk_buff *); | |
66 | static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, | |
67 | const union sctp_addr *laddr, | |
68 | const union sctp_addr *paddr, | |
69 | struct sctp_transport **transportp); | |
70 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr); | |
71 | static struct sctp_association *__sctp_lookup_association( | |
72 | const union sctp_addr *local, | |
73 | const union sctp_addr *peer, | |
74 | struct sctp_transport **pt); | |
75 | ||
61c9fed4 VY |
76 | static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb); |
77 | ||
1da177e4 LT |
78 | |
79 | /* Calculate the SCTP checksum of an SCTP packet. */ | |
80 | static inline int sctp_rcv_checksum(struct sk_buff *skb) | |
81 | { | |
1da177e4 | 82 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
2c0fd387 ACM |
83 | struct sctphdr *sh = sctp_hdr(skb); |
84 | __u32 cmp = ntohl(sh->checksum); | |
85 | __u32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); | |
1da177e4 LT |
86 | |
87 | for (; list; list = list->next) | |
88 | val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), | |
89 | val); | |
90 | ||
91 | val = sctp_end_cksum(val); | |
92 | ||
93 | if (val != cmp) { | |
94 | /* CRC failure, dump it. */ | |
95 | SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS); | |
96 | return -1; | |
97 | } | |
98 | return 0; | |
99 | } | |
100 | ||
79af02c2 DM |
101 | struct sctp_input_cb { |
102 | union { | |
103 | struct inet_skb_parm h4; | |
104 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
105 | struct inet6_skb_parm h6; | |
106 | #endif | |
107 | } header; | |
108 | struct sctp_chunk *chunk; | |
109 | }; | |
110 | #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) | |
111 | ||
1da177e4 LT |
112 | /* |
113 | * This is the routine which IP calls when receiving an SCTP packet. | |
114 | */ | |
115 | int sctp_rcv(struct sk_buff *skb) | |
116 | { | |
117 | struct sock *sk; | |
118 | struct sctp_association *asoc; | |
119 | struct sctp_endpoint *ep = NULL; | |
120 | struct sctp_ep_common *rcvr; | |
121 | struct sctp_transport *transport = NULL; | |
122 | struct sctp_chunk *chunk; | |
123 | struct sctphdr *sh; | |
124 | union sctp_addr src; | |
125 | union sctp_addr dest; | |
126 | int family; | |
127 | struct sctp_af *af; | |
1da177e4 LT |
128 | |
129 | if (skb->pkt_type!=PACKET_HOST) | |
130 | goto discard_it; | |
131 | ||
132 | SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS); | |
133 | ||
28cd7752 HX |
134 | if (skb_linearize(skb)) |
135 | goto discard_it; | |
136 | ||
2c0fd387 | 137 | sh = sctp_hdr(skb); |
1da177e4 LT |
138 | |
139 | /* Pull up the IP and SCTP headers. */ | |
ea2ae17d | 140 | __skb_pull(skb, skb_transport_offset(skb)); |
1da177e4 LT |
141 | if (skb->len < sizeof(struct sctphdr)) |
142 | goto discard_it; | |
503b55fd SS |
143 | if ((skb->ip_summed != CHECKSUM_UNNECESSARY) && |
144 | (sctp_rcv_checksum(skb) < 0)) | |
1da177e4 LT |
145 | goto discard_it; |
146 | ||
147 | skb_pull(skb, sizeof(struct sctphdr)); | |
148 | ||
149 | /* Make sure we at least have chunk headers worth of data left. */ | |
150 | if (skb->len < sizeof(struct sctp_chunkhdr)) | |
151 | goto discard_it; | |
152 | ||
eddc9ec5 | 153 | family = ipver2af(ip_hdr(skb)->version); |
1da177e4 LT |
154 | af = sctp_get_af_specific(family); |
155 | if (unlikely(!af)) | |
156 | goto discard_it; | |
157 | ||
158 | /* Initialize local addresses for lookups. */ | |
159 | af->from_skb(&src, skb, 1); | |
160 | af->from_skb(&dest, skb, 0); | |
161 | ||
162 | /* If the packet is to or from a non-unicast address, | |
163 | * silently discard the packet. | |
164 | * | |
165 | * This is not clearly defined in the RFC except in section | |
166 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
167 | * Transmission Protocol" 2.1, "It is important to note that the | |
168 | * IP address of an SCTP transport address must be a routable | |
169 | * unicast address. In other words, IP multicast addresses and | |
170 | * IP broadcast addresses cannot be used in an SCTP transport | |
171 | * address." | |
172 | */ | |
5636bef7 VY |
173 | if (!af->addr_valid(&src, NULL, skb) || |
174 | !af->addr_valid(&dest, NULL, skb)) | |
1da177e4 LT |
175 | goto discard_it; |
176 | ||
d55c41b1 | 177 | asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport); |
1c7d1fc1 | 178 | |
0fd9a65a | 179 | if (!asoc) |
d55c41b1 | 180 | ep = __sctp_rcv_lookup_endpoint(&dest); |
0fd9a65a NH |
181 | |
182 | /* Retrieve the common input handling substructure. */ | |
183 | rcvr = asoc ? &asoc->base : &ep->base; | |
184 | sk = rcvr->sk; | |
185 | ||
186 | /* | |
187 | * If a frame arrives on an interface and the receiving socket is | |
188 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
189 | */ | |
190 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) | |
191 | { | |
0fd9a65a NH |
192 | if (asoc) { |
193 | sctp_association_put(asoc); | |
194 | asoc = NULL; | |
195 | } else { | |
196 | sctp_endpoint_put(ep); | |
197 | ep = NULL; | |
198 | } | |
199 | sk = sctp_get_ctl_sock(); | |
200 | ep = sctp_sk(sk)->ep; | |
201 | sctp_endpoint_hold(ep); | |
0fd9a65a NH |
202 | rcvr = &ep->base; |
203 | } | |
204 | ||
1da177e4 LT |
205 | /* |
206 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
207 | * An SCTP packet is called an "out of the blue" (OOTB) | |
208 | * packet if it is correctly formed, i.e., passed the | |
209 | * receiver's checksum check, but the receiver is not | |
210 | * able to identify the association to which this | |
211 | * packet belongs. | |
212 | */ | |
213 | if (!asoc) { | |
1da177e4 LT |
214 | if (sctp_rcv_ootb(skb)) { |
215 | SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES); | |
216 | goto discard_release; | |
217 | } | |
218 | } | |
219 | ||
1da177e4 LT |
220 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
221 | goto discard_release; | |
b59c2701 | 222 | nf_reset(skb); |
1da177e4 | 223 | |
fda9ef5d | 224 | if (sk_filter(sk, skb)) |
d808ad9a | 225 | goto discard_release; |
1da177e4 LT |
226 | |
227 | /* Create an SCTP packet structure. */ | |
228 | chunk = sctp_chunkify(skb, asoc, sk); | |
2babf9da | 229 | if (!chunk) |
1da177e4 | 230 | goto discard_release; |
79af02c2 | 231 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 232 | |
1da177e4 LT |
233 | /* Remember what endpoint is to handle this packet. */ |
234 | chunk->rcvr = rcvr; | |
235 | ||
236 | /* Remember the SCTP header. */ | |
237 | chunk->sctp_hdr = sh; | |
238 | ||
239 | /* Set the source and destination addresses of the incoming chunk. */ | |
d55c41b1 | 240 | sctp_init_addrs(chunk, &src, &dest); |
1da177e4 LT |
241 | |
242 | /* Remember where we came from. */ | |
243 | chunk->transport = transport; | |
244 | ||
245 | /* Acquire access to the sock lock. Note: We are safe from other | |
246 | * bottom halves on this lock, but a user may be in the lock too, | |
247 | * so check if it is busy. | |
248 | */ | |
249 | sctp_bh_lock_sock(sk); | |
250 | ||
ac0b0462 SS |
251 | if (sock_owned_by_user(sk)) { |
252 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG); | |
61c9fed4 | 253 | sctp_add_backlog(sk, skb); |
ac0b0462 SS |
254 | } else { |
255 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ); | |
61c9fed4 | 256 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 257 | } |
1da177e4 | 258 | |
1da177e4 | 259 | sctp_bh_unlock_sock(sk); |
61c9fed4 VY |
260 | |
261 | /* Release the asoc/ep ref we took in the lookup calls. */ | |
262 | if (asoc) | |
263 | sctp_association_put(asoc); | |
264 | else | |
265 | sctp_endpoint_put(ep); | |
7a48f923 | 266 | |
2babf9da | 267 | return 0; |
1da177e4 LT |
268 | |
269 | discard_it: | |
ac0b0462 | 270 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS); |
1da177e4 | 271 | kfree_skb(skb); |
2babf9da | 272 | return 0; |
1da177e4 LT |
273 | |
274 | discard_release: | |
61c9fed4 | 275 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 276 | if (asoc) |
1da177e4 | 277 | sctp_association_put(asoc); |
0fd9a65a | 278 | else |
1da177e4 | 279 | sctp_endpoint_put(ep); |
1da177e4 LT |
280 | |
281 | goto discard_it; | |
282 | } | |
283 | ||
61c9fed4 VY |
284 | /* Process the backlog queue of the socket. Every skb on |
285 | * the backlog holds a ref on an association or endpoint. | |
286 | * We hold this ref throughout the state machine to make | |
287 | * sure that the structure we need is still around. | |
1da177e4 LT |
288 | */ |
289 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
290 | { | |
79af02c2 | 291 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
d808ad9a YH |
292 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
293 | struct sctp_ep_common *rcvr = NULL; | |
61c9fed4 | 294 | int backloged = 0; |
7a48f923 | 295 | |
d808ad9a | 296 | rcvr = chunk->rcvr; |
c4d2444e | 297 | |
61c9fed4 VY |
298 | /* If the rcvr is dead then the association or endpoint |
299 | * has been deleted and we can safely drop the chunk | |
300 | * and refs that we are holding. | |
301 | */ | |
302 | if (rcvr->dead) { | |
303 | sctp_chunk_free(chunk); | |
304 | goto done; | |
305 | } | |
306 | ||
307 | if (unlikely(rcvr->sk != sk)) { | |
308 | /* In this case, the association moved from one socket to | |
309 | * another. We are currently sitting on the backlog of the | |
310 | * old socket, so we need to move. | |
311 | * However, since we are here in the process context we | |
312 | * need to take make sure that the user doesn't own | |
313 | * the new socket when we process the packet. | |
314 | * If the new socket is user-owned, queue the chunk to the | |
315 | * backlog of the new socket without dropping any refs. | |
316 | * Otherwise, we can safely push the chunk on the inqueue. | |
317 | */ | |
318 | ||
319 | sk = rcvr->sk; | |
320 | sctp_bh_lock_sock(sk); | |
321 | ||
322 | if (sock_owned_by_user(sk)) { | |
323 | sk_add_backlog(sk, skb); | |
324 | backloged = 1; | |
325 | } else | |
326 | sctp_inq_push(inqueue, chunk); | |
327 | ||
328 | sctp_bh_unlock_sock(sk); | |
329 | ||
330 | /* If the chunk was backloged again, don't drop refs */ | |
331 | if (backloged) | |
332 | return 0; | |
333 | } else { | |
334 | sctp_inq_push(inqueue, chunk); | |
335 | } | |
336 | ||
337 | done: | |
338 | /* Release the refs we took in sctp_add_backlog */ | |
339 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
340 | sctp_association_put(sctp_assoc(rcvr)); | |
341 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
342 | sctp_endpoint_put(sctp_ep(rcvr)); | |
343 | else | |
344 | BUG(); | |
345 | ||
d808ad9a | 346 | return 0; |
1da177e4 LT |
347 | } |
348 | ||
61c9fed4 | 349 | static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 350 | { |
61c9fed4 VY |
351 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
352 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
c4d2444e | 353 | |
61c9fed4 VY |
354 | /* Hold the assoc/ep while hanging on the backlog queue. |
355 | * This way, we know structures we need will not disappear from us | |
356 | */ | |
357 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
358 | sctp_association_hold(sctp_assoc(rcvr)); | |
359 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
360 | sctp_endpoint_hold(sctp_ep(rcvr)); | |
361 | else | |
362 | BUG(); | |
363 | ||
364 | sk_add_backlog(sk, skb); | |
c4d2444e SS |
365 | } |
366 | ||
1da177e4 LT |
367 | /* Handle icmp frag needed error. */ |
368 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
369 | struct sctp_transport *t, __u32 pmtu) | |
370 | { | |
52ccb8e9 FF |
371 | if (sock_owned_by_user(sk) || !t || (t->pathmtu == pmtu)) |
372 | return; | |
373 | ||
374 | if (t->param_flags & SPP_PMTUD_ENABLE) { | |
375 | if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) { | |
376 | printk(KERN_WARNING "%s: Reported pmtu %d too low, " | |
377 | "using default minimum of %d\n", | |
378 | __FUNCTION__, pmtu, | |
379 | SCTP_DEFAULT_MINSEGMENT); | |
380 | /* Use default minimum segment size and disable | |
381 | * pmtu discovery on this transport. | |
382 | */ | |
383 | t->pathmtu = SCTP_DEFAULT_MINSEGMENT; | |
b56bab46 | 384 | t->param_flags = (t->param_flags & ~SPP_PMTUD) | |
52ccb8e9 FF |
385 | SPP_PMTUD_DISABLE; |
386 | } else { | |
387 | t->pathmtu = pmtu; | |
388 | } | |
1da177e4 | 389 | |
52ccb8e9 | 390 | /* Update association pmtu. */ |
1da177e4 | 391 | sctp_assoc_sync_pmtu(asoc); |
1da177e4 | 392 | } |
52ccb8e9 FF |
393 | |
394 | /* Retransmit with the new pmtu setting. | |
395 | * Normally, if PMTU discovery is disabled, an ICMP Fragmentation | |
396 | * Needed will never be sent, but if a message was sent before | |
397 | * PMTU discovery was disabled that was larger than the PMTU, it | |
d808ad9a | 398 | * would not be fragmented, so it must be re-transmitted fragmented. |
52ccb8e9 FF |
399 | */ |
400 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
401 | } |
402 | ||
403 | /* | |
404 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
405 | * | |
406 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
407 | * or a "Protocol Unreachable" treat this message as an abort | |
408 | * with the T bit set. | |
409 | * | |
410 | * This function sends an event to the state machine, which will abort the | |
411 | * association. | |
412 | * | |
413 | */ | |
414 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
d808ad9a YH |
415 | struct sctp_association *asoc, |
416 | struct sctp_transport *t) | |
1da177e4 LT |
417 | { |
418 | SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__); | |
419 | ||
420 | sctp_do_sm(SCTP_EVENT_T_OTHER, | |
421 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), | |
3f7a87d2 | 422 | asoc->state, asoc->ep, asoc, t, |
1da177e4 LT |
423 | GFP_ATOMIC); |
424 | ||
425 | } | |
426 | ||
427 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
428 | struct sock *sctp_err_lookup(int family, struct sk_buff *skb, | |
429 | struct sctphdr *sctphdr, | |
1da177e4 LT |
430 | struct sctp_association **app, |
431 | struct sctp_transport **tpp) | |
432 | { | |
433 | union sctp_addr saddr; | |
434 | union sctp_addr daddr; | |
435 | struct sctp_af *af; | |
436 | struct sock *sk = NULL; | |
8de8c873 | 437 | struct sctp_association *asoc; |
1da177e4 LT |
438 | struct sctp_transport *transport = NULL; |
439 | ||
d1ad1ff2 | 440 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
441 | |
442 | af = sctp_get_af_specific(family); | |
443 | if (unlikely(!af)) { | |
444 | return NULL; | |
445 | } | |
446 | ||
447 | /* Initialize local addresses for lookups. */ | |
448 | af->from_skb(&saddr, skb, 1); | |
449 | af->from_skb(&daddr, skb, 0); | |
450 | ||
451 | /* Look for an association that matches the incoming ICMP error | |
452 | * packet. | |
453 | */ | |
d55c41b1 | 454 | asoc = __sctp_lookup_association(&saddr, &daddr, &transport); |
d1ad1ff2 SS |
455 | if (!asoc) |
456 | return NULL; | |
1da177e4 | 457 | |
d1ad1ff2 | 458 | sk = asoc->base.sk; |
1da177e4 | 459 | |
d1ad1ff2 SS |
460 | if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) { |
461 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
462 | goto out; | |
463 | } | |
1da177e4 LT |
464 | |
465 | sctp_bh_lock_sock(sk); | |
466 | ||
467 | /* If too many ICMPs get dropped on busy | |
468 | * servers this needs to be solved differently. | |
469 | */ | |
470 | if (sock_owned_by_user(sk)) | |
471 | NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); | |
472 | ||
1da177e4 LT |
473 | *app = asoc; |
474 | *tpp = transport; | |
475 | return sk; | |
476 | ||
477 | out: | |
1da177e4 LT |
478 | if (asoc) |
479 | sctp_association_put(asoc); | |
1da177e4 LT |
480 | return NULL; |
481 | } | |
482 | ||
483 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 484 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
485 | { |
486 | sctp_bh_unlock_sock(sk); | |
1da177e4 LT |
487 | if (asoc) |
488 | sctp_association_put(asoc); | |
1da177e4 LT |
489 | } |
490 | ||
491 | /* | |
492 | * This routine is called by the ICMP module when it gets some | |
493 | * sort of error condition. If err < 0 then the socket should | |
494 | * be closed and the error returned to the user. If err > 0 | |
495 | * it's just the icmp type << 8 | icmp code. After adjustment | |
496 | * header points to the first 8 bytes of the sctp header. We need | |
497 | * to find the appropriate port. | |
498 | * | |
499 | * The locking strategy used here is very "optimistic". When | |
500 | * someone else accesses the socket the ICMP is just dropped | |
501 | * and for some paths there is no check at all. | |
502 | * A more general error queue to queue errors for later handling | |
503 | * is probably better. | |
504 | * | |
505 | */ | |
506 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
507 | { | |
508 | struct iphdr *iph = (struct iphdr *)skb->data; | |
a27ef749 | 509 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
510 | const int type = icmp_hdr(skb)->type; |
511 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 512 | struct sock *sk; |
8de8c873 | 513 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
514 | struct sctp_transport *transport; |
515 | struct inet_sock *inet; | |
2e07fa9c | 516 | sk_buff_data_t saveip, savesctp; |
1da177e4 LT |
517 | int err; |
518 | ||
a27ef749 | 519 | if (skb->len < ihlen + 8) { |
1da177e4 LT |
520 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); |
521 | return; | |
522 | } | |
523 | ||
524 | /* Fix up skb to look at the embedded net header. */ | |
b0e380b1 ACM |
525 | saveip = skb->network_header; |
526 | savesctp = skb->transport_header; | |
31c7711b | 527 | skb_reset_network_header(skb); |
a27ef749 ACM |
528 | skb_set_transport_header(skb, ihlen); |
529 | sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport); | |
2e07fa9c | 530 | /* Put back, the original values. */ |
b0e380b1 ACM |
531 | skb->network_header = saveip; |
532 | skb->transport_header = savesctp; | |
1da177e4 LT |
533 | if (!sk) { |
534 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
535 | return; | |
536 | } | |
537 | /* Warning: The sock lock is held. Remember to call | |
538 | * sctp_err_finish! | |
539 | */ | |
540 | ||
541 | switch (type) { | |
542 | case ICMP_PARAMETERPROB: | |
543 | err = EPROTO; | |
544 | break; | |
545 | case ICMP_DEST_UNREACH: | |
546 | if (code > NR_ICMP_UNREACH) | |
547 | goto out_unlock; | |
548 | ||
549 | /* PMTU discovery (RFC1191) */ | |
550 | if (ICMP_FRAG_NEEDED == code) { | |
551 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
552 | goto out_unlock; | |
553 | } | |
554 | else { | |
555 | if (ICMP_PROT_UNREACH == code) { | |
d1ad1ff2 | 556 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
557 | transport); |
558 | goto out_unlock; | |
559 | } | |
560 | } | |
561 | err = icmp_err_convert[code].errno; | |
562 | break; | |
563 | case ICMP_TIME_EXCEEDED: | |
564 | /* Ignore any time exceeded errors due to fragment reassembly | |
565 | * timeouts. | |
566 | */ | |
567 | if (ICMP_EXC_FRAGTIME == code) | |
568 | goto out_unlock; | |
569 | ||
570 | err = EHOSTUNREACH; | |
571 | break; | |
572 | default: | |
573 | goto out_unlock; | |
574 | } | |
575 | ||
576 | inet = inet_sk(sk); | |
577 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
578 | sk->sk_err = err; | |
579 | sk->sk_error_report(sk); | |
580 | } else { /* Only an error on timeout */ | |
581 | sk->sk_err_soft = err; | |
582 | } | |
583 | ||
584 | out_unlock: | |
d1ad1ff2 | 585 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
586 | } |
587 | ||
588 | /* | |
589 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
590 | * | |
591 | * This function scans all the chunks in the OOTB packet to determine if | |
592 | * the packet should be discarded right away. If a response might be needed | |
593 | * for this packet, or, if further processing is possible, the packet will | |
594 | * be queued to a proper inqueue for the next phase of handling. | |
595 | * | |
596 | * Output: | |
597 | * Return 0 - If further processing is needed. | |
598 | * Return 1 - If the packet can be discarded right away. | |
599 | */ | |
600 | int sctp_rcv_ootb(struct sk_buff *skb) | |
601 | { | |
602 | sctp_chunkhdr_t *ch; | |
603 | __u8 *ch_end; | |
604 | sctp_errhdr_t *err; | |
605 | ||
606 | ch = (sctp_chunkhdr_t *) skb->data; | |
1da177e4 LT |
607 | |
608 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 TF |
609 | do { |
610 | /* Break out if chunk length is less then minimal. */ | |
611 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
612 | break; | |
613 | ||
614 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
27a884dc | 615 | if (ch_end > skb_tail_pointer(skb)) |
a7d1f1b6 | 616 | break; |
1da177e4 LT |
617 | |
618 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
619 | * receiver MUST silently discard the OOTB packet and take no | |
620 | * further action. | |
621 | */ | |
622 | if (SCTP_CID_ABORT == ch->type) | |
623 | goto discard; | |
624 | ||
625 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
626 | * chunk, the receiver should silently discard the packet | |
627 | * and take no further action. | |
628 | */ | |
629 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
630 | goto discard; | |
631 | ||
632 | /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR | |
633 | * or a COOKIE ACK the SCTP Packet should be silently | |
634 | * discarded. | |
635 | */ | |
636 | if (SCTP_CID_COOKIE_ACK == ch->type) | |
637 | goto discard; | |
638 | ||
639 | if (SCTP_CID_ERROR == ch->type) { | |
640 | sctp_walk_errors(err, ch) { | |
641 | if (SCTP_ERROR_STALE_COOKIE == err->cause) | |
642 | goto discard; | |
643 | } | |
644 | } | |
645 | ||
646 | ch = (sctp_chunkhdr_t *) ch_end; | |
27a884dc | 647 | } while (ch_end < skb_tail_pointer(skb)); |
1da177e4 LT |
648 | |
649 | return 0; | |
650 | ||
651 | discard: | |
652 | return 1; | |
653 | } | |
654 | ||
655 | /* Insert endpoint into the hash table. */ | |
656 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
657 | { | |
658 | struct sctp_ep_common **epp; | |
659 | struct sctp_ep_common *epb; | |
660 | struct sctp_hashbucket *head; | |
661 | ||
662 | epb = &ep->base; | |
663 | ||
664 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
665 | head = &sctp_ep_hashtable[epb->hashent]; | |
666 | ||
667 | sctp_write_lock(&head->lock); | |
668 | epp = &head->chain; | |
669 | epb->next = *epp; | |
670 | if (epb->next) | |
671 | (*epp)->pprev = &epb->next; | |
672 | *epp = epb; | |
673 | epb->pprev = epp; | |
674 | sctp_write_unlock(&head->lock); | |
675 | } | |
676 | ||
677 | /* Add an endpoint to the hash. Local BH-safe. */ | |
678 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
679 | { | |
680 | sctp_local_bh_disable(); | |
681 | __sctp_hash_endpoint(ep); | |
682 | sctp_local_bh_enable(); | |
683 | } | |
684 | ||
685 | /* Remove endpoint from the hash table. */ | |
686 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
687 | { | |
688 | struct sctp_hashbucket *head; | |
689 | struct sctp_ep_common *epb; | |
690 | ||
691 | epb = &ep->base; | |
692 | ||
693 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
694 | ||
695 | head = &sctp_ep_hashtable[epb->hashent]; | |
696 | ||
697 | sctp_write_lock(&head->lock); | |
698 | ||
699 | if (epb->pprev) { | |
700 | if (epb->next) | |
701 | epb->next->pprev = epb->pprev; | |
702 | *epb->pprev = epb->next; | |
703 | epb->pprev = NULL; | |
704 | } | |
705 | ||
706 | sctp_write_unlock(&head->lock); | |
707 | } | |
708 | ||
709 | /* Remove endpoint from the hash. Local BH-safe. */ | |
710 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
711 | { | |
712 | sctp_local_bh_disable(); | |
713 | __sctp_unhash_endpoint(ep); | |
714 | sctp_local_bh_enable(); | |
715 | } | |
716 | ||
717 | /* Look up an endpoint. */ | |
718 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr) | |
719 | { | |
720 | struct sctp_hashbucket *head; | |
721 | struct sctp_ep_common *epb; | |
722 | struct sctp_endpoint *ep; | |
723 | int hash; | |
724 | ||
1c7d1fc1 | 725 | hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
726 | head = &sctp_ep_hashtable[hash]; |
727 | read_lock(&head->lock); | |
728 | for (epb = head->chain; epb; epb = epb->next) { | |
729 | ep = sctp_ep(epb); | |
730 | if (sctp_endpoint_is_match(ep, laddr)) | |
731 | goto hit; | |
732 | } | |
733 | ||
734 | ep = sctp_sk((sctp_get_ctl_sock()))->ep; | |
735 | epb = &ep->base; | |
736 | ||
737 | hit: | |
738 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
739 | read_unlock(&head->lock); |
740 | return ep; | |
741 | } | |
742 | ||
743 | /* Insert association into the hash table. */ | |
744 | static void __sctp_hash_established(struct sctp_association *asoc) | |
745 | { | |
746 | struct sctp_ep_common **epp; | |
747 | struct sctp_ep_common *epb; | |
748 | struct sctp_hashbucket *head; | |
749 | ||
750 | epb = &asoc->base; | |
751 | ||
752 | /* Calculate which chain this entry will belong to. */ | |
753 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port); | |
754 | ||
755 | head = &sctp_assoc_hashtable[epb->hashent]; | |
756 | ||
757 | sctp_write_lock(&head->lock); | |
758 | epp = &head->chain; | |
759 | epb->next = *epp; | |
760 | if (epb->next) | |
761 | (*epp)->pprev = &epb->next; | |
762 | *epp = epb; | |
763 | epb->pprev = epp; | |
764 | sctp_write_unlock(&head->lock); | |
765 | } | |
766 | ||
767 | /* Add an association to the hash. Local BH-safe. */ | |
768 | void sctp_hash_established(struct sctp_association *asoc) | |
769 | { | |
de76e695 VY |
770 | if (asoc->temp) |
771 | return; | |
772 | ||
1da177e4 LT |
773 | sctp_local_bh_disable(); |
774 | __sctp_hash_established(asoc); | |
775 | sctp_local_bh_enable(); | |
776 | } | |
777 | ||
778 | /* Remove association from the hash table. */ | |
779 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
780 | { | |
781 | struct sctp_hashbucket *head; | |
782 | struct sctp_ep_common *epb; | |
783 | ||
784 | epb = &asoc->base; | |
785 | ||
786 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, | |
787 | asoc->peer.port); | |
788 | ||
789 | head = &sctp_assoc_hashtable[epb->hashent]; | |
790 | ||
791 | sctp_write_lock(&head->lock); | |
792 | ||
793 | if (epb->pprev) { | |
794 | if (epb->next) | |
795 | epb->next->pprev = epb->pprev; | |
796 | *epb->pprev = epb->next; | |
797 | epb->pprev = NULL; | |
798 | } | |
799 | ||
800 | sctp_write_unlock(&head->lock); | |
801 | } | |
802 | ||
803 | /* Remove association from the hash table. Local BH-safe. */ | |
804 | void sctp_unhash_established(struct sctp_association *asoc) | |
805 | { | |
de76e695 VY |
806 | if (asoc->temp) |
807 | return; | |
808 | ||
1da177e4 LT |
809 | sctp_local_bh_disable(); |
810 | __sctp_unhash_established(asoc); | |
811 | sctp_local_bh_enable(); | |
812 | } | |
813 | ||
814 | /* Look up an association. */ | |
815 | static struct sctp_association *__sctp_lookup_association( | |
816 | const union sctp_addr *local, | |
817 | const union sctp_addr *peer, | |
818 | struct sctp_transport **pt) | |
819 | { | |
820 | struct sctp_hashbucket *head; | |
821 | struct sctp_ep_common *epb; | |
822 | struct sctp_association *asoc; | |
823 | struct sctp_transport *transport; | |
824 | int hash; | |
825 | ||
826 | /* Optimize here for direct hit, only listening connections can | |
827 | * have wildcards anyways. | |
828 | */ | |
e2fccedb | 829 | hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port)); |
1da177e4 LT |
830 | head = &sctp_assoc_hashtable[hash]; |
831 | read_lock(&head->lock); | |
832 | for (epb = head->chain; epb; epb = epb->next) { | |
833 | asoc = sctp_assoc(epb); | |
834 | transport = sctp_assoc_is_match(asoc, local, peer); | |
835 | if (transport) | |
836 | goto hit; | |
837 | } | |
838 | ||
839 | read_unlock(&head->lock); | |
840 | ||
841 | return NULL; | |
842 | ||
843 | hit: | |
844 | *pt = transport; | |
845 | sctp_association_hold(asoc); | |
1da177e4 LT |
846 | read_unlock(&head->lock); |
847 | return asoc; | |
848 | } | |
849 | ||
850 | /* Look up an association. BH-safe. */ | |
851 | SCTP_STATIC | |
852 | struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr, | |
853 | const union sctp_addr *paddr, | |
854 | struct sctp_transport **transportp) | |
855 | { | |
856 | struct sctp_association *asoc; | |
857 | ||
858 | sctp_local_bh_disable(); | |
859 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
860 | sctp_local_bh_enable(); | |
861 | ||
862 | return asoc; | |
863 | } | |
864 | ||
865 | /* Is there an association matching the given local and peer addresses? */ | |
866 | int sctp_has_association(const union sctp_addr *laddr, | |
867 | const union sctp_addr *paddr) | |
868 | { | |
869 | struct sctp_association *asoc; | |
870 | struct sctp_transport *transport; | |
871 | ||
6c7be55c | 872 | if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) { |
1da177e4 LT |
873 | sctp_association_put(asoc); |
874 | return 1; | |
875 | } | |
876 | ||
877 | return 0; | |
878 | } | |
879 | ||
880 | /* | |
881 | * SCTP Implementors Guide, 2.18 Handling of address | |
882 | * parameters within the INIT or INIT-ACK. | |
883 | * | |
884 | * D) When searching for a matching TCB upon reception of an INIT | |
885 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
886 | * source address of the packet (containing the INIT or | |
887 | * INIT-ACK) but the receiver SHOULD also use all valid | |
888 | * address parameters contained within the chunk. | |
889 | * | |
890 | * 2.18.3 Solution description | |
891 | * | |
892 | * This new text clearly specifies to an implementor the need | |
893 | * to look within the INIT or INIT-ACK. Any implementation that | |
894 | * does not do this, may not be able to establish associations | |
895 | * in certain circumstances. | |
896 | * | |
897 | */ | |
898 | static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, | |
899 | const union sctp_addr *laddr, struct sctp_transport **transportp) | |
900 | { | |
901 | struct sctp_association *asoc; | |
902 | union sctp_addr addr; | |
903 | union sctp_addr *paddr = &addr; | |
2c0fd387 | 904 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
905 | sctp_chunkhdr_t *ch; |
906 | union sctp_params params; | |
907 | sctp_init_chunk_t *init; | |
908 | struct sctp_transport *transport; | |
909 | struct sctp_af *af; | |
910 | ||
911 | ch = (sctp_chunkhdr_t *) skb->data; | |
912 | ||
913 | /* If this is INIT/INIT-ACK look inside the chunk too. */ | |
914 | switch (ch->type) { | |
915 | case SCTP_CID_INIT: | |
916 | case SCTP_CID_INIT_ACK: | |
917 | break; | |
918 | default: | |
919 | return NULL; | |
920 | } | |
921 | ||
922 | /* The code below will attempt to walk the chunk and extract | |
923 | * parameter information. Before we do that, we need to verify | |
924 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
925 | * walk off the end. | |
926 | */ | |
927 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
928 | return NULL; | |
929 | ||
930 | /* | |
931 | * This code will NOT touch anything inside the chunk--it is | |
932 | * strictly READ-ONLY. | |
933 | * | |
934 | * RFC 2960 3 SCTP packet Format | |
935 | * | |
936 | * Multiple chunks can be bundled into one SCTP packet up to | |
937 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
938 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
939 | * other chunk in a packet. See Section 6.10 for more details | |
940 | * on chunk bundling. | |
941 | */ | |
942 | ||
943 | /* Find the start of the TLVs and the end of the chunk. This is | |
944 | * the region we search for address parameters. | |
945 | */ | |
946 | init = (sctp_init_chunk_t *)skb->data; | |
947 | ||
948 | /* Walk the parameters looking for embedded addresses. */ | |
949 | sctp_walk_params(params, init, init_hdr.params) { | |
950 | ||
951 | /* Note: Ignoring hostname addresses. */ | |
952 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
953 | if (!af) | |
954 | continue; | |
955 | ||
dd86d136 | 956 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 957 | |
dd86d136 | 958 | asoc = __sctp_lookup_association(laddr, paddr, &transport); |
1da177e4 LT |
959 | if (asoc) |
960 | return asoc; | |
961 | } | |
962 | ||
963 | return NULL; | |
964 | } | |
965 | ||
966 | /* Lookup an association for an inbound skb. */ | |
967 | static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, | |
968 | const union sctp_addr *paddr, | |
969 | const union sctp_addr *laddr, | |
970 | struct sctp_transport **transportp) | |
971 | { | |
972 | struct sctp_association *asoc; | |
973 | ||
974 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
975 | ||
976 | /* Further lookup for INIT/INIT-ACK packets. | |
977 | * SCTP Implementors Guide, 2.18 Handling of address | |
978 | * parameters within the INIT or INIT-ACK. | |
979 | */ | |
980 | if (!asoc) | |
981 | asoc = __sctp_rcv_init_lookup(skb, laddr, transportp); | |
982 | ||
983 | return asoc; | |
984 | } |