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60c778b2 | 1 | /* SCTP kernel implementation |
1da177e4 LT |
2 | * (C) Copyright IBM Corp. 2001, 2004 |
3 | * Copyright (c) 1999-2000 Cisco, Inc. | |
4 | * Copyright (c) 1999-2001 Motorola, Inc. | |
5 | * | |
60c778b2 | 6 | * This file is part of the SCTP kernel implementation |
1da177e4 LT |
7 | * |
8 | * These functions handle output processing. | |
9 | * | |
60c778b2 | 10 | * This SCTP implementation is free software; |
1da177e4 LT |
11 | * you can redistribute it and/or modify it under the terms of |
12 | * the GNU General Public License as published by | |
13 | * the Free Software Foundation; either version 2, or (at your option) | |
14 | * any later version. | |
15 | * | |
60c778b2 | 16 | * This SCTP implementation is distributed in the hope that it |
1da177e4 LT |
17 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
18 | * ************************ | |
19 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
20 | * See the GNU General Public License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License | |
23 | * along with GNU CC; see the file COPYING. If not, write to | |
24 | * the Free Software Foundation, 59 Temple Place - Suite 330, | |
25 | * Boston, MA 02111-1307, USA. | |
26 | * | |
27 | * Please send any bug reports or fixes you make to the | |
28 | * email address(es): | |
29 | * lksctp developers <lksctp-developers@lists.sourceforge.net> | |
30 | * | |
31 | * Or submit a bug report through the following website: | |
32 | * http://www.sf.net/projects/lksctp | |
33 | * | |
34 | * Written or modified by: | |
35 | * La Monte H.P. Yarroll <piggy@acm.org> | |
36 | * Karl Knutson <karl@athena.chicago.il.us> | |
37 | * Jon Grimm <jgrimm@austin.ibm.com> | |
38 | * Sridhar Samudrala <sri@us.ibm.com> | |
39 | * | |
40 | * Any bugs reported given to us we will try to fix... any fixes shared will | |
41 | * be incorporated into the next SCTP release. | |
42 | */ | |
43 | ||
145ce502 JP |
44 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
45 | ||
1da177e4 LT |
46 | #include <linux/types.h> |
47 | #include <linux/kernel.h> | |
48 | #include <linux/wait.h> | |
49 | #include <linux/time.h> | |
50 | #include <linux/ip.h> | |
51 | #include <linux/ipv6.h> | |
52 | #include <linux/init.h> | |
5a0e3ad6 | 53 | #include <linux/slab.h> |
1da177e4 | 54 | #include <net/inet_ecn.h> |
8d2f9e81 | 55 | #include <net/ip.h> |
1da177e4 | 56 | #include <net/icmp.h> |
7c73a6fa | 57 | #include <net/net_namespace.h> |
1da177e4 | 58 | |
1da177e4 LT |
59 | #include <linux/socket.h> /* for sa_family_t */ |
60 | #include <net/sock.h> | |
61 | ||
62 | #include <net/sctp/sctp.h> | |
63 | #include <net/sctp/sm.h> | |
9ad0977f | 64 | #include <net/sctp/checksum.h> |
1da177e4 LT |
65 | |
66 | /* Forward declarations for private helpers. */ | |
ed106277 NH |
67 | static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet, |
68 | struct sctp_chunk *chunk); | |
e83963b7 | 69 | static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet, |
1da177e4 | 70 | struct sctp_chunk *chunk); |
e83963b7 VY |
71 | static void sctp_packet_append_data(struct sctp_packet *packet, |
72 | struct sctp_chunk *chunk); | |
73 | static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet, | |
74 | struct sctp_chunk *chunk, | |
75 | u16 chunk_len); | |
1da177e4 | 76 | |
be297143 WY |
77 | static void sctp_packet_reset(struct sctp_packet *packet) |
78 | { | |
79 | packet->size = packet->overhead; | |
80 | packet->has_cookie_echo = 0; | |
81 | packet->has_sack = 0; | |
82 | packet->has_data = 0; | |
83 | packet->has_auth = 0; | |
84 | packet->ipfragok = 0; | |
85 | packet->auth = NULL; | |
86 | } | |
87 | ||
1da177e4 LT |
88 | /* Config a packet. |
89 | * This appears to be a followup set of initializations. | |
90 | */ | |
91 | struct sctp_packet *sctp_packet_config(struct sctp_packet *packet, | |
92 | __u32 vtag, int ecn_capable) | |
93 | { | |
94 | struct sctp_chunk *chunk = NULL; | |
95 | ||
0dc47877 | 96 | SCTP_DEBUG_PRINTK("%s: packet:%p vtag:0x%x\n", __func__, |
1da177e4 LT |
97 | packet, vtag); |
98 | ||
99 | packet->vtag = vtag; | |
1da177e4 LT |
100 | |
101 | if (ecn_capable && sctp_packet_empty(packet)) { | |
102 | chunk = sctp_get_ecne_prepend(packet->transport->asoc); | |
103 | ||
104 | /* If there a is a prepend chunk stick it on the list before | |
d808ad9a YH |
105 | * any other chunks get appended. |
106 | */ | |
1da177e4 LT |
107 | if (chunk) |
108 | sctp_packet_append_chunk(packet, chunk); | |
109 | } | |
110 | ||
111 | return packet; | |
112 | } | |
113 | ||
114 | /* Initialize the packet structure. */ | |
115 | struct sctp_packet *sctp_packet_init(struct sctp_packet *packet, | |
116 | struct sctp_transport *transport, | |
117 | __u16 sport, __u16 dport) | |
118 | { | |
119 | struct sctp_association *asoc = transport->asoc; | |
120 | size_t overhead; | |
121 | ||
0dc47877 | 122 | SCTP_DEBUG_PRINTK("%s: packet:%p transport:%p\n", __func__, |
1da177e4 LT |
123 | packet, transport); |
124 | ||
125 | packet->transport = transport; | |
126 | packet->source_port = sport; | |
127 | packet->destination_port = dport; | |
79af02c2 | 128 | INIT_LIST_HEAD(&packet->chunk_list); |
1da177e4 | 129 | if (asoc) { |
d808ad9a YH |
130 | struct sctp_sock *sp = sctp_sk(asoc->base.sk); |
131 | overhead = sp->pf->af->net_header_len; | |
1da177e4 LT |
132 | } else { |
133 | overhead = sizeof(struct ipv6hdr); | |
134 | } | |
135 | overhead += sizeof(struct sctphdr); | |
136 | packet->overhead = overhead; | |
be297143 | 137 | sctp_packet_reset(packet); |
1da177e4 | 138 | packet->vtag = 0; |
1da177e4 LT |
139 | packet->malloced = 0; |
140 | return packet; | |
141 | } | |
142 | ||
143 | /* Free a packet. */ | |
144 | void sctp_packet_free(struct sctp_packet *packet) | |
145 | { | |
79af02c2 | 146 | struct sctp_chunk *chunk, *tmp; |
1da177e4 | 147 | |
0dc47877 | 148 | SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet); |
1da177e4 | 149 | |
79af02c2 DM |
150 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
151 | list_del_init(&chunk->list); | |
1da177e4 | 152 | sctp_chunk_free(chunk); |
79af02c2 | 153 | } |
1da177e4 LT |
154 | |
155 | if (packet->malloced) | |
156 | kfree(packet); | |
157 | } | |
158 | ||
159 | /* This routine tries to append the chunk to the offered packet. If adding | |
160 | * the chunk causes the packet to exceed the path MTU and COOKIE_ECHO chunk | |
161 | * is not present in the packet, it transmits the input packet. | |
162 | * Data can be bundled with a packet containing a COOKIE_ECHO chunk as long | |
163 | * as it can fit in the packet, but any more data that does not fit in this | |
164 | * packet can be sent only after receiving the COOKIE_ACK. | |
165 | */ | |
166 | sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *packet, | |
2e3216cd VY |
167 | struct sctp_chunk *chunk, |
168 | int one_packet) | |
1da177e4 LT |
169 | { |
170 | sctp_xmit_t retval; | |
171 | int error = 0; | |
172 | ||
0dc47877 | 173 | SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__, |
1da177e4 LT |
174 | packet, chunk); |
175 | ||
176 | switch ((retval = (sctp_packet_append_chunk(packet, chunk)))) { | |
177 | case SCTP_XMIT_PMTU_FULL: | |
178 | if (!packet->has_cookie_echo) { | |
179 | error = sctp_packet_transmit(packet); | |
180 | if (error < 0) | |
181 | chunk->skb->sk->sk_err = -error; | |
182 | ||
183 | /* If we have an empty packet, then we can NOT ever | |
184 | * return PMTU_FULL. | |
185 | */ | |
2e3216cd VY |
186 | if (!one_packet) |
187 | retval = sctp_packet_append_chunk(packet, | |
188 | chunk); | |
1da177e4 LT |
189 | } |
190 | break; | |
191 | ||
192 | case SCTP_XMIT_RWND_FULL: | |
193 | case SCTP_XMIT_OK: | |
194 | case SCTP_XMIT_NAGLE_DELAY: | |
195 | break; | |
3ff50b79 | 196 | } |
1da177e4 LT |
197 | |
198 | return retval; | |
199 | } | |
200 | ||
4cd57c80 VY |
201 | /* Try to bundle an auth chunk into the packet. */ |
202 | static sctp_xmit_t sctp_packet_bundle_auth(struct sctp_packet *pkt, | |
203 | struct sctp_chunk *chunk) | |
204 | { | |
205 | struct sctp_association *asoc = pkt->transport->asoc; | |
206 | struct sctp_chunk *auth; | |
207 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
208 | ||
209 | /* if we don't have an association, we can't do authentication */ | |
210 | if (!asoc) | |
211 | return retval; | |
212 | ||
213 | /* See if this is an auth chunk we are bundling or if | |
214 | * auth is already bundled. | |
215 | */ | |
4007cc88 | 216 | if (chunk->chunk_hdr->type == SCTP_CID_AUTH || pkt->has_auth) |
4cd57c80 VY |
217 | return retval; |
218 | ||
219 | /* if the peer did not request this chunk to be authenticated, | |
220 | * don't do it | |
221 | */ | |
222 | if (!chunk->auth) | |
223 | return retval; | |
224 | ||
225 | auth = sctp_make_auth(asoc); | |
226 | if (!auth) | |
227 | return retval; | |
228 | ||
ed106277 NH |
229 | retval = __sctp_packet_append_chunk(pkt, auth); |
230 | ||
231 | if (retval != SCTP_XMIT_OK) | |
232 | sctp_chunk_free(auth); | |
4cd57c80 VY |
233 | |
234 | return retval; | |
235 | } | |
236 | ||
1da177e4 LT |
237 | /* Try to bundle a SACK with the packet. */ |
238 | static sctp_xmit_t sctp_packet_bundle_sack(struct sctp_packet *pkt, | |
239 | struct sctp_chunk *chunk) | |
240 | { | |
241 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
242 | ||
243 | /* If sending DATA and haven't aleady bundled a SACK, try to | |
244 | * bundle one in to the packet. | |
245 | */ | |
246 | if (sctp_chunk_is_data(chunk) && !pkt->has_sack && | |
247 | !pkt->has_cookie_echo) { | |
248 | struct sctp_association *asoc; | |
af87b823 | 249 | struct timer_list *timer; |
1da177e4 | 250 | asoc = pkt->transport->asoc; |
af87b823 | 251 | timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK]; |
1da177e4 | 252 | |
af87b823 DG |
253 | /* If the SACK timer is running, we have a pending SACK */ |
254 | if (timer_pending(timer)) { | |
1da177e4 | 255 | struct sctp_chunk *sack; |
4244854d NH |
256 | |
257 | if (pkt->transport->sack_generation != | |
258 | pkt->transport->asoc->peer.sack_generation) | |
259 | return retval; | |
260 | ||
1da177e4 LT |
261 | asoc->a_rwnd = asoc->rwnd; |
262 | sack = sctp_make_sack(asoc); | |
263 | if (sack) { | |
ed106277 NH |
264 | retval = __sctp_packet_append_chunk(pkt, sack); |
265 | if (retval != SCTP_XMIT_OK) { | |
266 | sctp_chunk_free(sack); | |
267 | goto out; | |
268 | } | |
1da177e4 | 269 | asoc->peer.sack_needed = 0; |
af87b823 | 270 | if (del_timer(timer)) |
1da177e4 LT |
271 | sctp_association_put(asoc); |
272 | } | |
273 | } | |
274 | } | |
ed106277 | 275 | out: |
1da177e4 LT |
276 | return retval; |
277 | } | |
278 | ||
ed106277 | 279 | |
1da177e4 LT |
280 | /* Append a chunk to the offered packet reporting back any inability to do |
281 | * so. | |
282 | */ | |
ed106277 NH |
283 | static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet, |
284 | struct sctp_chunk *chunk) | |
1da177e4 LT |
285 | { |
286 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
287 | __u16 chunk_len = WORD_ROUND(ntohs(chunk->chunk_hdr->length)); | |
1da177e4 | 288 | |
e83963b7 VY |
289 | /* Check to see if this chunk will fit into the packet */ |
290 | retval = sctp_packet_will_fit(packet, chunk, chunk_len); | |
291 | if (retval != SCTP_XMIT_OK) | |
292 | goto finish; | |
1da177e4 | 293 | |
e83963b7 | 294 | /* We believe that this chunk is OK to add to the packet */ |
4cd57c80 VY |
295 | switch (chunk->chunk_hdr->type) { |
296 | case SCTP_CID_DATA: | |
e83963b7 VY |
297 | /* Account for the data being in the packet */ |
298 | sctp_packet_append_data(packet, chunk); | |
1da177e4 LT |
299 | /* Disallow SACK bundling after DATA. */ |
300 | packet->has_sack = 1; | |
4cd57c80 VY |
301 | /* Disallow AUTH bundling after DATA */ |
302 | packet->has_auth = 1; | |
303 | /* Let it be knows that packet has DATA in it */ | |
304 | packet->has_data = 1; | |
759af00e VY |
305 | /* timestamp the chunk for rtx purposes */ |
306 | chunk->sent_at = jiffies; | |
4cd57c80 VY |
307 | break; |
308 | case SCTP_CID_COOKIE_ECHO: | |
1da177e4 | 309 | packet->has_cookie_echo = 1; |
4cd57c80 VY |
310 | break; |
311 | ||
312 | case SCTP_CID_SACK: | |
1da177e4 | 313 | packet->has_sack = 1; |
4cd57c80 VY |
314 | break; |
315 | ||
316 | case SCTP_CID_AUTH: | |
317 | packet->has_auth = 1; | |
318 | packet->auth = chunk; | |
319 | break; | |
320 | } | |
1da177e4 LT |
321 | |
322 | /* It is OK to send this chunk. */ | |
79af02c2 | 323 | list_add_tail(&chunk->list, &packet->chunk_list); |
1da177e4 LT |
324 | packet->size += chunk_len; |
325 | chunk->transport = packet->transport; | |
326 | finish: | |
327 | return retval; | |
328 | } | |
329 | ||
ed106277 NH |
330 | /* Append a chunk to the offered packet reporting back any inability to do |
331 | * so. | |
332 | */ | |
333 | sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *packet, | |
334 | struct sctp_chunk *chunk) | |
335 | { | |
336 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
337 | ||
338 | SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__, packet, | |
339 | chunk); | |
340 | ||
341 | /* Data chunks are special. Before seeing what else we can | |
342 | * bundle into this packet, check to see if we are allowed to | |
343 | * send this DATA. | |
344 | */ | |
345 | if (sctp_chunk_is_data(chunk)) { | |
346 | retval = sctp_packet_can_append_data(packet, chunk); | |
347 | if (retval != SCTP_XMIT_OK) | |
348 | goto finish; | |
349 | } | |
350 | ||
351 | /* Try to bundle AUTH chunk */ | |
352 | retval = sctp_packet_bundle_auth(packet, chunk); | |
353 | if (retval != SCTP_XMIT_OK) | |
354 | goto finish; | |
355 | ||
356 | /* Try to bundle SACK chunk */ | |
357 | retval = sctp_packet_bundle_sack(packet, chunk); | |
358 | if (retval != SCTP_XMIT_OK) | |
359 | goto finish; | |
360 | ||
361 | retval = __sctp_packet_append_chunk(packet, chunk); | |
362 | ||
363 | finish: | |
364 | return retval; | |
365 | } | |
366 | ||
4c3a5bda TG |
367 | static void sctp_packet_release_owner(struct sk_buff *skb) |
368 | { | |
369 | sk_free(skb->sk); | |
370 | } | |
371 | ||
372 | static void sctp_packet_set_owner_w(struct sk_buff *skb, struct sock *sk) | |
373 | { | |
374 | skb_orphan(skb); | |
375 | skb->sk = sk; | |
376 | skb->destructor = sctp_packet_release_owner; | |
377 | ||
378 | /* | |
379 | * The data chunks have already been accounted for in sctp_sendmsg(), | |
380 | * therefore only reserve a single byte to keep socket around until | |
381 | * the packet has been transmitted. | |
382 | */ | |
383 | atomic_inc(&sk->sk_wmem_alloc); | |
384 | } | |
385 | ||
1da177e4 LT |
386 | /* All packets are sent to the network through this function from |
387 | * sctp_outq_tail(). | |
388 | * | |
389 | * The return value is a normal kernel error return value. | |
390 | */ | |
391 | int sctp_packet_transmit(struct sctp_packet *packet) | |
392 | { | |
393 | struct sctp_transport *tp = packet->transport; | |
394 | struct sctp_association *asoc = tp->asoc; | |
395 | struct sctphdr *sh; | |
1da177e4 | 396 | struct sk_buff *nskb; |
79af02c2 | 397 | struct sctp_chunk *chunk, *tmp; |
1da177e4 LT |
398 | struct sock *sk; |
399 | int err = 0; | |
400 | int padding; /* How much padding do we need? */ | |
401 | __u8 has_data = 0; | |
503b55fd | 402 | struct dst_entry *dst = tp->dst; |
4cd57c80 VY |
403 | unsigned char *auth = NULL; /* pointer to auth in skb data */ |
404 | __u32 cksum_buf_len = sizeof(struct sctphdr); | |
1da177e4 | 405 | |
0dc47877 | 406 | SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet); |
1da177e4 LT |
407 | |
408 | /* Do NOT generate a chunkless packet. */ | |
79af02c2 | 409 | if (list_empty(&packet->chunk_list)) |
1da177e4 LT |
410 | return err; |
411 | ||
412 | /* Set up convenience variables... */ | |
79af02c2 | 413 | chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list); |
1da177e4 LT |
414 | sk = chunk->skb->sk; |
415 | ||
416 | /* Allocate the new skb. */ | |
594ccc14 | 417 | nskb = alloc_skb(packet->size + LL_MAX_HEADER, GFP_ATOMIC); |
1da177e4 LT |
418 | if (!nskb) |
419 | goto nomem; | |
420 | ||
421 | /* Make sure the outbound skb has enough header room reserved. */ | |
594ccc14 | 422 | skb_reserve(nskb, packet->overhead + LL_MAX_HEADER); |
1da177e4 LT |
423 | |
424 | /* Set the owning socket so that we know where to get the | |
425 | * destination IP address. | |
426 | */ | |
4c3a5bda | 427 | sctp_packet_set_owner_w(nskb, sk); |
1da177e4 | 428 | |
e0268868 | 429 | if (!sctp_transport_dst_check(tp)) { |
503b55fd SS |
430 | sctp_transport_route(tp, NULL, sctp_sk(sk)); |
431 | if (asoc && (asoc->param_flags & SPP_PMTUD_ENABLE)) { | |
02f3d4ce | 432 | sctp_assoc_sync_pmtu(sk, asoc); |
503b55fd SS |
433 | } |
434 | } | |
adf30907 ED |
435 | dst = dst_clone(tp->dst); |
436 | skb_dst_set(nskb, dst); | |
ff0ac74a | 437 | if (!dst) |
503b55fd | 438 | goto no_route; |
503b55fd | 439 | |
1da177e4 LT |
440 | /* Build the SCTP header. */ |
441 | sh = (struct sctphdr *)skb_push(nskb, sizeof(struct sctphdr)); | |
8dc92f7e | 442 | skb_reset_transport_header(nskb); |
1da177e4 LT |
443 | sh->source = htons(packet->source_port); |
444 | sh->dest = htons(packet->destination_port); | |
445 | ||
446 | /* From 6.8 Adler-32 Checksum Calculation: | |
447 | * After the packet is constructed (containing the SCTP common | |
448 | * header and one or more control or DATA chunks), the | |
449 | * transmitter shall: | |
450 | * | |
451 | * 1) Fill in the proper Verification Tag in the SCTP common | |
452 | * header and initialize the checksum field to 0's. | |
453 | */ | |
454 | sh->vtag = htonl(packet->vtag); | |
455 | sh->checksum = 0; | |
456 | ||
1da177e4 LT |
457 | /** |
458 | * 6.10 Bundling | |
459 | * | |
460 | * An endpoint bundles chunks by simply including multiple | |
461 | * chunks in one outbound SCTP packet. ... | |
462 | */ | |
463 | ||
464 | /** | |
465 | * 3.2 Chunk Field Descriptions | |
466 | * | |
467 | * The total length of a chunk (including Type, Length and | |
468 | * Value fields) MUST be a multiple of 4 bytes. If the length | |
469 | * of the chunk is not a multiple of 4 bytes, the sender MUST | |
470 | * pad the chunk with all zero bytes and this padding is not | |
471 | * included in the chunk length field. The sender should | |
472 | * never pad with more than 3 bytes. | |
473 | * | |
474 | * [This whole comment explains WORD_ROUND() below.] | |
475 | */ | |
476 | SCTP_DEBUG_PRINTK("***sctp_transmit_packet***\n"); | |
79af02c2 DM |
477 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
478 | list_del_init(&chunk->list); | |
1da177e4 | 479 | if (sctp_chunk_is_data(chunk)) { |
ae19c548 VY |
480 | /* 6.3.1 C4) When data is in flight and when allowed |
481 | * by rule C5, a new RTT measurement MUST be made each | |
482 | * round trip. Furthermore, new RTT measurements | |
483 | * SHOULD be made no more than once per round-trip | |
484 | * for a given destination transport address. | |
485 | */ | |
1da177e4 | 486 | |
ae19c548 VY |
487 | if (!tp->rto_pending) { |
488 | chunk->rtt_in_progress = 1; | |
489 | tp->rto_pending = 1; | |
d8dd1578 | 490 | } |
1da177e4 LT |
491 | has_data = 1; |
492 | } | |
493 | ||
494 | padding = WORD_ROUND(chunk->skb->len) - chunk->skb->len; | |
495 | if (padding) | |
496 | memset(skb_put(chunk->skb, padding), 0, padding); | |
497 | ||
4cd57c80 VY |
498 | /* if this is the auth chunk that we are adding, |
499 | * store pointer where it will be added and put | |
500 | * the auth into the packet. | |
501 | */ | |
502 | if (chunk == packet->auth) | |
503 | auth = skb_tail_pointer(nskb); | |
504 | ||
505 | cksum_buf_len += chunk->skb->len; | |
506 | memcpy(skb_put(nskb, chunk->skb->len), | |
503b55fd | 507 | chunk->skb->data, chunk->skb->len); |
1da177e4 LT |
508 | |
509 | SCTP_DEBUG_PRINTK("%s %p[%s] %s 0x%x, %s %d, %s %d, %s %d\n", | |
510 | "*** Chunk", chunk, | |
511 | sctp_cname(SCTP_ST_CHUNK( | |
512 | chunk->chunk_hdr->type)), | |
513 | chunk->has_tsn ? "TSN" : "No TSN", | |
514 | chunk->has_tsn ? | |
515 | ntohl(chunk->subh.data_hdr->tsn) : 0, | |
516 | "length", ntohs(chunk->chunk_hdr->length), | |
517 | "chunk->skb->len", chunk->skb->len, | |
518 | "rtt_in_progress", chunk->rtt_in_progress); | |
519 | ||
520 | /* | |
521 | * If this is a control chunk, this is our last | |
522 | * reference. Free data chunks after they've been | |
523 | * acknowledged or have failed. | |
524 | */ | |
525 | if (!sctp_chunk_is_data(chunk)) | |
d808ad9a | 526 | sctp_chunk_free(chunk); |
1da177e4 LT |
527 | } |
528 | ||
4cd57c80 VY |
529 | /* SCTP-AUTH, Section 6.2 |
530 | * The sender MUST calculate the MAC as described in RFC2104 [2] | |
531 | * using the hash function H as described by the MAC Identifier and | |
532 | * the shared association key K based on the endpoint pair shared key | |
533 | * described by the shared key identifier. The 'data' used for the | |
534 | * computation of the AUTH-chunk is given by the AUTH chunk with its | |
535 | * HMAC field set to zero (as shown in Figure 6) followed by all | |
536 | * chunks that are placed after the AUTH chunk in the SCTP packet. | |
537 | */ | |
538 | if (auth) | |
539 | sctp_auth_calculate_hmac(asoc, nskb, | |
540 | (struct sctp_auth_chunk *)auth, | |
541 | GFP_ATOMIC); | |
542 | ||
543 | /* 2) Calculate the Adler-32 checksum of the whole packet, | |
544 | * including the SCTP common header and all the | |
545 | * chunks. | |
546 | * | |
547 | * Note: Adler-32 is no longer applicable, as has been replaced | |
548 | * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>. | |
549 | */ | |
b73c43f8 MM |
550 | if (!sctp_checksum_disable) { |
551 | if (!(dst->dev->features & NETIF_F_SCTP_CSUM)) { | |
552 | __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len); | |
4458f04c | 553 | |
b73c43f8 MM |
554 | /* 3) Put the resultant value into the checksum field in the |
555 | * common header, and leave the rest of the bits unchanged. | |
556 | */ | |
557 | sh->checksum = sctp_end_cksum(crc32); | |
558 | } else { | |
25985edc | 559 | /* no need to seed pseudo checksum for SCTP */ |
8dc92f7e JB |
560 | nskb->ip_summed = CHECKSUM_PARTIAL; |
561 | nskb->csum_start = (skb_transport_header(nskb) - | |
562 | nskb->head); | |
563 | nskb->csum_offset = offsetof(struct sctphdr, checksum); | |
8dc92f7e JB |
564 | } |
565 | } | |
1da177e4 | 566 | |
1da177e4 LT |
567 | /* IP layer ECN support |
568 | * From RFC 2481 | |
569 | * "The ECN-Capable Transport (ECT) bit would be set by the | |
570 | * data sender to indicate that the end-points of the | |
571 | * transport protocol are ECN-capable." | |
572 | * | |
573 | * Now setting the ECT bit all the time, as it should not cause | |
574 | * any problems protocol-wise even if our peer ignores it. | |
575 | * | |
576 | * Note: The works for IPv6 layer checks this bit too later | |
577 | * in transmission. See IP6_ECN_flow_xmit(). | |
578 | */ | |
b9031d9d | 579 | (*tp->af_specific->ecn_capable)(nskb->sk); |
1da177e4 LT |
580 | |
581 | /* Set up the IP options. */ | |
582 | /* BUG: not implemented | |
583 | * For v4 this all lives somewhere in sk->sk_opt... | |
584 | */ | |
585 | ||
586 | /* Dump that on IP! */ | |
587 | if (asoc && asoc->peer.last_sent_to != tp) { | |
588 | /* Considering the multiple CPU scenario, this is a | |
589 | * "correcter" place for last_sent_to. --xguo | |
590 | */ | |
591 | asoc->peer.last_sent_to = tp; | |
592 | } | |
593 | ||
594 | if (has_data) { | |
595 | struct timer_list *timer; | |
596 | unsigned long timeout; | |
597 | ||
1da177e4 LT |
598 | /* Restart the AUTOCLOSE timer when sending data. */ |
599 | if (sctp_state(asoc, ESTABLISHED) && asoc->autoclose) { | |
600 | timer = &asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]; | |
601 | timeout = asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]; | |
602 | ||
603 | if (!mod_timer(timer, jiffies + timeout)) | |
604 | sctp_association_hold(asoc); | |
605 | } | |
606 | } | |
607 | ||
1da177e4 LT |
608 | SCTP_DEBUG_PRINTK("***sctp_transmit_packet*** skb len %d\n", |
609 | nskb->len); | |
610 | ||
f880374c HX |
611 | nskb->local_df = packet->ipfragok; |
612 | (*tp->af_specific->sctp_xmit)(nskb, tp); | |
1da177e4 LT |
613 | |
614 | out: | |
d521c08f | 615 | sctp_packet_reset(packet); |
1da177e4 LT |
616 | return err; |
617 | no_route: | |
618 | kfree_skb(nskb); | |
b01a2407 | 619 | IP_INC_STATS_BH(sock_net(asoc->base.sk), IPSTATS_MIB_OUTNOROUTES); |
1da177e4 LT |
620 | |
621 | /* FIXME: Returning the 'err' will effect all the associations | |
622 | * associated with a socket, although only one of the paths of the | |
623 | * association is unreachable. | |
624 | * The real failure of a transport or association can be passed on | |
625 | * to the user via notifications. So setting this error may not be | |
626 | * required. | |
627 | */ | |
628 | /* err = -EHOSTUNREACH; */ | |
629 | err: | |
630 | /* Control chunks are unreliable so just drop them. DATA chunks | |
631 | * will get resent or dropped later. | |
632 | */ | |
633 | ||
79af02c2 DM |
634 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
635 | list_del_init(&chunk->list); | |
1da177e4 | 636 | if (!sctp_chunk_is_data(chunk)) |
d808ad9a | 637 | sctp_chunk_free(chunk); |
1da177e4 LT |
638 | } |
639 | goto out; | |
640 | nomem: | |
641 | err = -ENOMEM; | |
642 | goto err; | |
643 | } | |
644 | ||
645 | /******************************************************************** | |
646 | * 2nd Level Abstractions | |
647 | ********************************************************************/ | |
648 | ||
e83963b7 VY |
649 | /* This private function check to see if a chunk can be added */ |
650 | static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet, | |
1da177e4 LT |
651 | struct sctp_chunk *chunk) |
652 | { | |
653 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
e83963b7 | 654 | size_t datasize, rwnd, inflight, flight_size; |
1da177e4 | 655 | struct sctp_transport *transport = packet->transport; |
1da177e4 | 656 | struct sctp_association *asoc = transport->asoc; |
1da177e4 LT |
657 | struct sctp_outq *q = &asoc->outqueue; |
658 | ||
659 | /* RFC 2960 6.1 Transmission of DATA Chunks | |
660 | * | |
661 | * A) At any given time, the data sender MUST NOT transmit new data to | |
662 | * any destination transport address if its peer's rwnd indicates | |
663 | * that the peer has no buffer space (i.e. rwnd is 0, see Section | |
664 | * 6.2.1). However, regardless of the value of rwnd (including if it | |
665 | * is 0), the data sender can always have one DATA chunk in flight to | |
666 | * the receiver if allowed by cwnd (see rule B below). This rule | |
667 | * allows the sender to probe for a change in rwnd that the sender | |
668 | * missed due to the SACK having been lost in transit from the data | |
669 | * receiver to the data sender. | |
670 | */ | |
671 | ||
672 | rwnd = asoc->peer.rwnd; | |
e83963b7 VY |
673 | inflight = q->outstanding_bytes; |
674 | flight_size = transport->flight_size; | |
1da177e4 LT |
675 | |
676 | datasize = sctp_data_size(chunk); | |
677 | ||
678 | if (datasize > rwnd) { | |
679 | if (inflight > 0) { | |
680 | /* We have (at least) one data chunk in flight, | |
681 | * so we can't fall back to rule 6.1 B). | |
682 | */ | |
683 | retval = SCTP_XMIT_RWND_FULL; | |
684 | goto finish; | |
685 | } | |
686 | } | |
687 | ||
1da177e4 LT |
688 | /* RFC 2960 6.1 Transmission of DATA Chunks |
689 | * | |
690 | * B) At any given time, the sender MUST NOT transmit new data | |
691 | * to a given transport address if it has cwnd or more bytes | |
692 | * of data outstanding to that transport address. | |
693 | */ | |
694 | /* RFC 7.2.4 & the Implementers Guide 2.8. | |
695 | * | |
696 | * 3) ... | |
697 | * When a Fast Retransmit is being performed the sender SHOULD | |
698 | * ignore the value of cwnd and SHOULD NOT delay retransmission. | |
699 | */ | |
c226ef9b | 700 | if (chunk->fast_retransmit != SCTP_NEED_FRTX) |
e83963b7 | 701 | if (flight_size >= transport->cwnd) { |
1da177e4 LT |
702 | retval = SCTP_XMIT_RWND_FULL; |
703 | goto finish; | |
704 | } | |
705 | ||
706 | /* Nagle's algorithm to solve small-packet problem: | |
707 | * Inhibit the sending of new chunks when new outgoing data arrives | |
708 | * if any previously transmitted data on the connection remains | |
709 | * unacknowledged. | |
710 | */ | |
e83963b7 VY |
711 | if (!sctp_sk(asoc->base.sk)->nodelay && sctp_packet_empty(packet) && |
712 | inflight && sctp_state(asoc, ESTABLISHED)) { | |
95c96174 ED |
713 | unsigned int max = transport->pathmtu - packet->overhead; |
714 | unsigned int len = chunk->skb->len + q->out_qlen; | |
1da177e4 LT |
715 | |
716 | /* Check whether this chunk and all the rest of pending | |
717 | * data will fit or delay in hopes of bundling a full | |
718 | * sized packet. | |
cb95ea32 VY |
719 | * Don't delay large message writes that may have been |
720 | * fragmeneted into small peices. | |
1da177e4 | 721 | */ |
0e3aef8d | 722 | if ((len < max) && chunk->msg->can_delay) { |
1da177e4 LT |
723 | retval = SCTP_XMIT_NAGLE_DELAY; |
724 | goto finish; | |
725 | } | |
726 | } | |
727 | ||
e83963b7 VY |
728 | finish: |
729 | return retval; | |
730 | } | |
731 | ||
732 | /* This private function does management things when adding DATA chunk */ | |
733 | static void sctp_packet_append_data(struct sctp_packet *packet, | |
734 | struct sctp_chunk *chunk) | |
735 | { | |
736 | struct sctp_transport *transport = packet->transport; | |
737 | size_t datasize = sctp_data_size(chunk); | |
738 | struct sctp_association *asoc = transport->asoc; | |
739 | u32 rwnd = asoc->peer.rwnd; | |
740 | ||
1da177e4 LT |
741 | /* Keep track of how many bytes are in flight over this transport. */ |
742 | transport->flight_size += datasize; | |
743 | ||
744 | /* Keep track of how many bytes are in flight to the receiver. */ | |
745 | asoc->outqueue.outstanding_bytes += datasize; | |
746 | ||
a76c0adf | 747 | /* Update our view of the receiver's rwnd. */ |
1da177e4 LT |
748 | if (datasize < rwnd) |
749 | rwnd -= datasize; | |
750 | else | |
751 | rwnd = 0; | |
752 | ||
753 | asoc->peer.rwnd = rwnd; | |
754 | /* Has been accepted for transmission. */ | |
755 | if (!asoc->peer.prsctp_capable) | |
756 | chunk->msg->can_abandon = 0; | |
d8dd1578 NH |
757 | sctp_chunk_assign_tsn(chunk); |
758 | sctp_chunk_assign_ssn(chunk); | |
e83963b7 VY |
759 | } |
760 | ||
761 | static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet, | |
762 | struct sctp_chunk *chunk, | |
763 | u16 chunk_len) | |
764 | { | |
765 | size_t psize; | |
766 | size_t pmtu; | |
767 | int too_big; | |
768 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
769 | ||
770 | psize = packet->size; | |
771 | pmtu = ((packet->transport->asoc) ? | |
772 | (packet->transport->asoc->pathmtu) : | |
773 | (packet->transport->pathmtu)); | |
774 | ||
775 | too_big = (psize + chunk_len > pmtu); | |
776 | ||
777 | /* Decide if we need to fragment or resubmit later. */ | |
778 | if (too_big) { | |
779 | /* It's OK to fragmet at IP level if any one of the following | |
780 | * is true: | |
781 | * 1. The packet is empty (meaning this chunk is greater | |
782 | * the MTU) | |
783 | * 2. The chunk we are adding is a control chunk | |
784 | * 3. The packet doesn't have any data in it yet and data | |
785 | * requires authentication. | |
786 | */ | |
787 | if (sctp_packet_empty(packet) || !sctp_chunk_is_data(chunk) || | |
788 | (!packet->has_data && chunk->auth)) { | |
789 | /* We no longer do re-fragmentation. | |
790 | * Just fragment at the IP layer, if we | |
791 | * actually hit this condition | |
792 | */ | |
793 | packet->ipfragok = 1; | |
794 | } else { | |
795 | retval = SCTP_XMIT_PMTU_FULL; | |
796 | } | |
797 | } | |
1da177e4 | 798 | |
1da177e4 LT |
799 | return retval; |
800 | } |