]>
Commit | Line | Data |
---|---|---|
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 | ||
bb33381d | 96 | pr_debug("%s: packet:%p vtag:0x%x\n", __func__, packet, vtag); |
1da177e4 LT |
97 | |
98 | packet->vtag = vtag; | |
1da177e4 LT |
99 | |
100 | if (ecn_capable && sctp_packet_empty(packet)) { | |
101 | chunk = sctp_get_ecne_prepend(packet->transport->asoc); | |
102 | ||
103 | /* If there a is a prepend chunk stick it on the list before | |
d808ad9a YH |
104 | * any other chunks get appended. |
105 | */ | |
1da177e4 LT |
106 | if (chunk) |
107 | sctp_packet_append_chunk(packet, chunk); | |
108 | } | |
109 | ||
110 | return packet; | |
111 | } | |
112 | ||
113 | /* Initialize the packet structure. */ | |
114 | struct sctp_packet *sctp_packet_init(struct sctp_packet *packet, | |
115 | struct sctp_transport *transport, | |
116 | __u16 sport, __u16 dport) | |
117 | { | |
118 | struct sctp_association *asoc = transport->asoc; | |
119 | size_t overhead; | |
120 | ||
bb33381d | 121 | pr_debug("%s: packet:%p transport:%p\n", __func__, packet, transport); |
1da177e4 LT |
122 | |
123 | packet->transport = transport; | |
124 | packet->source_port = sport; | |
125 | packet->destination_port = dport; | |
79af02c2 | 126 | INIT_LIST_HEAD(&packet->chunk_list); |
1da177e4 | 127 | if (asoc) { |
d808ad9a YH |
128 | struct sctp_sock *sp = sctp_sk(asoc->base.sk); |
129 | overhead = sp->pf->af->net_header_len; | |
1da177e4 LT |
130 | } else { |
131 | overhead = sizeof(struct ipv6hdr); | |
132 | } | |
133 | overhead += sizeof(struct sctphdr); | |
134 | packet->overhead = overhead; | |
be297143 | 135 | sctp_packet_reset(packet); |
1da177e4 | 136 | packet->vtag = 0; |
3e3251b3 | 137 | |
1da177e4 LT |
138 | return packet; |
139 | } | |
140 | ||
141 | /* Free a packet. */ | |
142 | void sctp_packet_free(struct sctp_packet *packet) | |
143 | { | |
79af02c2 | 144 | struct sctp_chunk *chunk, *tmp; |
1da177e4 | 145 | |
bb33381d | 146 | pr_debug("%s: packet:%p\n", __func__, packet); |
1da177e4 | 147 | |
79af02c2 DM |
148 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
149 | list_del_init(&chunk->list); | |
1da177e4 | 150 | sctp_chunk_free(chunk); |
79af02c2 | 151 | } |
1da177e4 LT |
152 | } |
153 | ||
154 | /* This routine tries to append the chunk to the offered packet. If adding | |
155 | * the chunk causes the packet to exceed the path MTU and COOKIE_ECHO chunk | |
156 | * is not present in the packet, it transmits the input packet. | |
157 | * Data can be bundled with a packet containing a COOKIE_ECHO chunk as long | |
158 | * as it can fit in the packet, but any more data that does not fit in this | |
159 | * packet can be sent only after receiving the COOKIE_ACK. | |
160 | */ | |
161 | sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *packet, | |
2e3216cd VY |
162 | struct sctp_chunk *chunk, |
163 | int one_packet) | |
1da177e4 LT |
164 | { |
165 | sctp_xmit_t retval; | |
166 | int error = 0; | |
167 | ||
bb33381d | 168 | pr_debug("%s: packet:%p chunk:%p\n", __func__, packet, chunk); |
1da177e4 LT |
169 | |
170 | switch ((retval = (sctp_packet_append_chunk(packet, chunk)))) { | |
171 | case SCTP_XMIT_PMTU_FULL: | |
172 | if (!packet->has_cookie_echo) { | |
173 | error = sctp_packet_transmit(packet); | |
174 | if (error < 0) | |
175 | chunk->skb->sk->sk_err = -error; | |
176 | ||
177 | /* If we have an empty packet, then we can NOT ever | |
178 | * return PMTU_FULL. | |
179 | */ | |
2e3216cd VY |
180 | if (!one_packet) |
181 | retval = sctp_packet_append_chunk(packet, | |
182 | chunk); | |
1da177e4 LT |
183 | } |
184 | break; | |
185 | ||
186 | case SCTP_XMIT_RWND_FULL: | |
187 | case SCTP_XMIT_OK: | |
188 | case SCTP_XMIT_NAGLE_DELAY: | |
189 | break; | |
3ff50b79 | 190 | } |
1da177e4 LT |
191 | |
192 | return retval; | |
193 | } | |
194 | ||
4cd57c80 VY |
195 | /* Try to bundle an auth chunk into the packet. */ |
196 | static sctp_xmit_t sctp_packet_bundle_auth(struct sctp_packet *pkt, | |
197 | struct sctp_chunk *chunk) | |
198 | { | |
199 | struct sctp_association *asoc = pkt->transport->asoc; | |
200 | struct sctp_chunk *auth; | |
201 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
202 | ||
203 | /* if we don't have an association, we can't do authentication */ | |
204 | if (!asoc) | |
205 | return retval; | |
206 | ||
207 | /* See if this is an auth chunk we are bundling or if | |
208 | * auth is already bundled. | |
209 | */ | |
4007cc88 | 210 | if (chunk->chunk_hdr->type == SCTP_CID_AUTH || pkt->has_auth) |
4cd57c80 VY |
211 | return retval; |
212 | ||
213 | /* if the peer did not request this chunk to be authenticated, | |
214 | * don't do it | |
215 | */ | |
216 | if (!chunk->auth) | |
217 | return retval; | |
218 | ||
219 | auth = sctp_make_auth(asoc); | |
220 | if (!auth) | |
221 | return retval; | |
222 | ||
ed106277 NH |
223 | retval = __sctp_packet_append_chunk(pkt, auth); |
224 | ||
225 | if (retval != SCTP_XMIT_OK) | |
226 | sctp_chunk_free(auth); | |
4cd57c80 VY |
227 | |
228 | return retval; | |
229 | } | |
230 | ||
1da177e4 LT |
231 | /* Try to bundle a SACK with the packet. */ |
232 | static sctp_xmit_t sctp_packet_bundle_sack(struct sctp_packet *pkt, | |
233 | struct sctp_chunk *chunk) | |
234 | { | |
235 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
236 | ||
237 | /* If sending DATA and haven't aleady bundled a SACK, try to | |
238 | * bundle one in to the packet. | |
239 | */ | |
240 | if (sctp_chunk_is_data(chunk) && !pkt->has_sack && | |
241 | !pkt->has_cookie_echo) { | |
242 | struct sctp_association *asoc; | |
af87b823 | 243 | struct timer_list *timer; |
1da177e4 | 244 | asoc = pkt->transport->asoc; |
af87b823 | 245 | timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK]; |
1da177e4 | 246 | |
af87b823 DG |
247 | /* If the SACK timer is running, we have a pending SACK */ |
248 | if (timer_pending(timer)) { | |
1da177e4 | 249 | struct sctp_chunk *sack; |
4244854d NH |
250 | |
251 | if (pkt->transport->sack_generation != | |
252 | pkt->transport->asoc->peer.sack_generation) | |
253 | return retval; | |
254 | ||
1da177e4 LT |
255 | asoc->a_rwnd = asoc->rwnd; |
256 | sack = sctp_make_sack(asoc); | |
257 | if (sack) { | |
ed106277 NH |
258 | retval = __sctp_packet_append_chunk(pkt, sack); |
259 | if (retval != SCTP_XMIT_OK) { | |
260 | sctp_chunk_free(sack); | |
261 | goto out; | |
262 | } | |
1da177e4 | 263 | asoc->peer.sack_needed = 0; |
af87b823 | 264 | if (del_timer(timer)) |
1da177e4 LT |
265 | sctp_association_put(asoc); |
266 | } | |
267 | } | |
268 | } | |
ed106277 | 269 | out: |
1da177e4 LT |
270 | return retval; |
271 | } | |
272 | ||
ed106277 | 273 | |
1da177e4 LT |
274 | /* Append a chunk to the offered packet reporting back any inability to do |
275 | * so. | |
276 | */ | |
ed106277 NH |
277 | static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet, |
278 | struct sctp_chunk *chunk) | |
1da177e4 LT |
279 | { |
280 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
281 | __u16 chunk_len = WORD_ROUND(ntohs(chunk->chunk_hdr->length)); | |
1da177e4 | 282 | |
e83963b7 VY |
283 | /* Check to see if this chunk will fit into the packet */ |
284 | retval = sctp_packet_will_fit(packet, chunk, chunk_len); | |
285 | if (retval != SCTP_XMIT_OK) | |
286 | goto finish; | |
1da177e4 | 287 | |
e83963b7 | 288 | /* We believe that this chunk is OK to add to the packet */ |
4cd57c80 VY |
289 | switch (chunk->chunk_hdr->type) { |
290 | case SCTP_CID_DATA: | |
e83963b7 VY |
291 | /* Account for the data being in the packet */ |
292 | sctp_packet_append_data(packet, chunk); | |
1da177e4 LT |
293 | /* Disallow SACK bundling after DATA. */ |
294 | packet->has_sack = 1; | |
4cd57c80 VY |
295 | /* Disallow AUTH bundling after DATA */ |
296 | packet->has_auth = 1; | |
297 | /* Let it be knows that packet has DATA in it */ | |
298 | packet->has_data = 1; | |
759af00e VY |
299 | /* timestamp the chunk for rtx purposes */ |
300 | chunk->sent_at = jiffies; | |
4cd57c80 VY |
301 | break; |
302 | case SCTP_CID_COOKIE_ECHO: | |
1da177e4 | 303 | packet->has_cookie_echo = 1; |
4cd57c80 VY |
304 | break; |
305 | ||
306 | case SCTP_CID_SACK: | |
1da177e4 | 307 | packet->has_sack = 1; |
196d6759 MB |
308 | if (chunk->asoc) |
309 | chunk->asoc->stats.osacks++; | |
4cd57c80 VY |
310 | break; |
311 | ||
312 | case SCTP_CID_AUTH: | |
313 | packet->has_auth = 1; | |
314 | packet->auth = chunk; | |
315 | break; | |
316 | } | |
1da177e4 LT |
317 | |
318 | /* It is OK to send this chunk. */ | |
79af02c2 | 319 | list_add_tail(&chunk->list, &packet->chunk_list); |
1da177e4 LT |
320 | packet->size += chunk_len; |
321 | chunk->transport = packet->transport; | |
322 | finish: | |
323 | return retval; | |
324 | } | |
325 | ||
ed106277 NH |
326 | /* Append a chunk to the offered packet reporting back any inability to do |
327 | * so. | |
328 | */ | |
329 | sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *packet, | |
330 | struct sctp_chunk *chunk) | |
331 | { | |
332 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
333 | ||
bb33381d | 334 | pr_debug("%s: packet:%p chunk:%p\n", __func__, packet, chunk); |
ed106277 NH |
335 | |
336 | /* Data chunks are special. Before seeing what else we can | |
337 | * bundle into this packet, check to see if we are allowed to | |
338 | * send this DATA. | |
339 | */ | |
340 | if (sctp_chunk_is_data(chunk)) { | |
341 | retval = sctp_packet_can_append_data(packet, chunk); | |
342 | if (retval != SCTP_XMIT_OK) | |
343 | goto finish; | |
344 | } | |
345 | ||
346 | /* Try to bundle AUTH chunk */ | |
347 | retval = sctp_packet_bundle_auth(packet, chunk); | |
348 | if (retval != SCTP_XMIT_OK) | |
349 | goto finish; | |
350 | ||
351 | /* Try to bundle SACK chunk */ | |
352 | retval = sctp_packet_bundle_sack(packet, chunk); | |
353 | if (retval != SCTP_XMIT_OK) | |
354 | goto finish; | |
355 | ||
356 | retval = __sctp_packet_append_chunk(packet, chunk); | |
357 | ||
358 | finish: | |
359 | return retval; | |
360 | } | |
361 | ||
4c3a5bda TG |
362 | static void sctp_packet_release_owner(struct sk_buff *skb) |
363 | { | |
364 | sk_free(skb->sk); | |
365 | } | |
366 | ||
367 | static void sctp_packet_set_owner_w(struct sk_buff *skb, struct sock *sk) | |
368 | { | |
369 | skb_orphan(skb); | |
370 | skb->sk = sk; | |
371 | skb->destructor = sctp_packet_release_owner; | |
372 | ||
373 | /* | |
374 | * The data chunks have already been accounted for in sctp_sendmsg(), | |
375 | * therefore only reserve a single byte to keep socket around until | |
376 | * the packet has been transmitted. | |
377 | */ | |
378 | atomic_inc(&sk->sk_wmem_alloc); | |
379 | } | |
380 | ||
1da177e4 LT |
381 | /* All packets are sent to the network through this function from |
382 | * sctp_outq_tail(). | |
383 | * | |
384 | * The return value is a normal kernel error return value. | |
385 | */ | |
386 | int sctp_packet_transmit(struct sctp_packet *packet) | |
387 | { | |
388 | struct sctp_transport *tp = packet->transport; | |
389 | struct sctp_association *asoc = tp->asoc; | |
390 | struct sctphdr *sh; | |
1da177e4 | 391 | struct sk_buff *nskb; |
79af02c2 | 392 | struct sctp_chunk *chunk, *tmp; |
1da177e4 LT |
393 | struct sock *sk; |
394 | int err = 0; | |
395 | int padding; /* How much padding do we need? */ | |
396 | __u8 has_data = 0; | |
503b55fd | 397 | struct dst_entry *dst = tp->dst; |
4cd57c80 VY |
398 | unsigned char *auth = NULL; /* pointer to auth in skb data */ |
399 | __u32 cksum_buf_len = sizeof(struct sctphdr); | |
1da177e4 | 400 | |
bb33381d | 401 | pr_debug("%s: packet:%p\n", __func__, packet); |
1da177e4 LT |
402 | |
403 | /* Do NOT generate a chunkless packet. */ | |
79af02c2 | 404 | if (list_empty(&packet->chunk_list)) |
1da177e4 LT |
405 | return err; |
406 | ||
407 | /* Set up convenience variables... */ | |
79af02c2 | 408 | chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list); |
1da177e4 LT |
409 | sk = chunk->skb->sk; |
410 | ||
411 | /* Allocate the new skb. */ | |
594ccc14 | 412 | nskb = alloc_skb(packet->size + LL_MAX_HEADER, GFP_ATOMIC); |
1da177e4 LT |
413 | if (!nskb) |
414 | goto nomem; | |
415 | ||
416 | /* Make sure the outbound skb has enough header room reserved. */ | |
594ccc14 | 417 | skb_reserve(nskb, packet->overhead + LL_MAX_HEADER); |
1da177e4 LT |
418 | |
419 | /* Set the owning socket so that we know where to get the | |
420 | * destination IP address. | |
421 | */ | |
4c3a5bda | 422 | sctp_packet_set_owner_w(nskb, sk); |
1da177e4 | 423 | |
e0268868 | 424 | if (!sctp_transport_dst_check(tp)) { |
503b55fd SS |
425 | sctp_transport_route(tp, NULL, sctp_sk(sk)); |
426 | if (asoc && (asoc->param_flags & SPP_PMTUD_ENABLE)) { | |
02f3d4ce | 427 | sctp_assoc_sync_pmtu(sk, asoc); |
503b55fd SS |
428 | } |
429 | } | |
adf30907 ED |
430 | dst = dst_clone(tp->dst); |
431 | skb_dst_set(nskb, dst); | |
ff0ac74a | 432 | if (!dst) |
503b55fd | 433 | goto no_route; |
503b55fd | 434 | |
1da177e4 LT |
435 | /* Build the SCTP header. */ |
436 | sh = (struct sctphdr *)skb_push(nskb, sizeof(struct sctphdr)); | |
8dc92f7e | 437 | skb_reset_transport_header(nskb); |
1da177e4 LT |
438 | sh->source = htons(packet->source_port); |
439 | sh->dest = htons(packet->destination_port); | |
440 | ||
441 | /* From 6.8 Adler-32 Checksum Calculation: | |
442 | * After the packet is constructed (containing the SCTP common | |
443 | * header and one or more control or DATA chunks), the | |
444 | * transmitter shall: | |
445 | * | |
446 | * 1) Fill in the proper Verification Tag in the SCTP common | |
447 | * header and initialize the checksum field to 0's. | |
448 | */ | |
449 | sh->vtag = htonl(packet->vtag); | |
450 | sh->checksum = 0; | |
451 | ||
1da177e4 LT |
452 | /** |
453 | * 6.10 Bundling | |
454 | * | |
455 | * An endpoint bundles chunks by simply including multiple | |
456 | * chunks in one outbound SCTP packet. ... | |
457 | */ | |
458 | ||
459 | /** | |
460 | * 3.2 Chunk Field Descriptions | |
461 | * | |
462 | * The total length of a chunk (including Type, Length and | |
463 | * Value fields) MUST be a multiple of 4 bytes. If the length | |
464 | * of the chunk is not a multiple of 4 bytes, the sender MUST | |
465 | * pad the chunk with all zero bytes and this padding is not | |
466 | * included in the chunk length field. The sender should | |
467 | * never pad with more than 3 bytes. | |
468 | * | |
469 | * [This whole comment explains WORD_ROUND() below.] | |
470 | */ | |
bb33381d DB |
471 | |
472 | pr_debug("***sctp_transmit_packet***\n"); | |
473 | ||
79af02c2 DM |
474 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
475 | list_del_init(&chunk->list); | |
1da177e4 | 476 | if (sctp_chunk_is_data(chunk)) { |
ae19c548 VY |
477 | /* 6.3.1 C4) When data is in flight and when allowed |
478 | * by rule C5, a new RTT measurement MUST be made each | |
479 | * round trip. Furthermore, new RTT measurements | |
480 | * SHOULD be made no more than once per round-trip | |
481 | * for a given destination transport address. | |
482 | */ | |
1da177e4 | 483 | |
ae19c548 VY |
484 | if (!tp->rto_pending) { |
485 | chunk->rtt_in_progress = 1; | |
486 | tp->rto_pending = 1; | |
d8dd1578 | 487 | } |
1da177e4 LT |
488 | has_data = 1; |
489 | } | |
490 | ||
491 | padding = WORD_ROUND(chunk->skb->len) - chunk->skb->len; | |
492 | if (padding) | |
493 | memset(skb_put(chunk->skb, padding), 0, padding); | |
494 | ||
4cd57c80 VY |
495 | /* if this is the auth chunk that we are adding, |
496 | * store pointer where it will be added and put | |
497 | * the auth into the packet. | |
498 | */ | |
499 | if (chunk == packet->auth) | |
500 | auth = skb_tail_pointer(nskb); | |
501 | ||
502 | cksum_buf_len += chunk->skb->len; | |
503 | memcpy(skb_put(nskb, chunk->skb->len), | |
503b55fd | 504 | chunk->skb->data, chunk->skb->len); |
1da177e4 | 505 | |
bb33381d DB |
506 | pr_debug("*** Chunk:%p[%s] %s 0x%x, length:%d, chunk->skb->len:%d, " |
507 | "rtt_in_progress:%d\n", chunk, | |
508 | sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), | |
509 | chunk->has_tsn ? "TSN" : "No TSN", | |
510 | chunk->has_tsn ? ntohl(chunk->subh.data_hdr->tsn) : 0, | |
511 | ntohs(chunk->chunk_hdr->length), chunk->skb->len, | |
512 | chunk->rtt_in_progress); | |
1da177e4 LT |
513 | |
514 | /* | |
515 | * If this is a control chunk, this is our last | |
516 | * reference. Free data chunks after they've been | |
517 | * acknowledged or have failed. | |
518 | */ | |
519 | if (!sctp_chunk_is_data(chunk)) | |
d808ad9a | 520 | sctp_chunk_free(chunk); |
1da177e4 LT |
521 | } |
522 | ||
4cd57c80 VY |
523 | /* SCTP-AUTH, Section 6.2 |
524 | * The sender MUST calculate the MAC as described in RFC2104 [2] | |
525 | * using the hash function H as described by the MAC Identifier and | |
526 | * the shared association key K based on the endpoint pair shared key | |
527 | * described by the shared key identifier. The 'data' used for the | |
528 | * computation of the AUTH-chunk is given by the AUTH chunk with its | |
529 | * HMAC field set to zero (as shown in Figure 6) followed by all | |
530 | * chunks that are placed after the AUTH chunk in the SCTP packet. | |
531 | */ | |
532 | if (auth) | |
533 | sctp_auth_calculate_hmac(asoc, nskb, | |
534 | (struct sctp_auth_chunk *)auth, | |
535 | GFP_ATOMIC); | |
536 | ||
537 | /* 2) Calculate the Adler-32 checksum of the whole packet, | |
538 | * including the SCTP common header and all the | |
539 | * chunks. | |
540 | * | |
541 | * Note: Adler-32 is no longer applicable, as has been replaced | |
542 | * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>. | |
543 | */ | |
b73c43f8 MM |
544 | if (!sctp_checksum_disable) { |
545 | if (!(dst->dev->features & NETIF_F_SCTP_CSUM)) { | |
546 | __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len); | |
4458f04c | 547 | |
b73c43f8 MM |
548 | /* 3) Put the resultant value into the checksum field in the |
549 | * common header, and leave the rest of the bits unchanged. | |
550 | */ | |
551 | sh->checksum = sctp_end_cksum(crc32); | |
552 | } else { | |
25985edc | 553 | /* no need to seed pseudo checksum for SCTP */ |
8dc92f7e JB |
554 | nskb->ip_summed = CHECKSUM_PARTIAL; |
555 | nskb->csum_start = (skb_transport_header(nskb) - | |
556 | nskb->head); | |
557 | nskb->csum_offset = offsetof(struct sctphdr, checksum); | |
8dc92f7e JB |
558 | } |
559 | } | |
1da177e4 | 560 | |
1da177e4 LT |
561 | /* IP layer ECN support |
562 | * From RFC 2481 | |
563 | * "The ECN-Capable Transport (ECT) bit would be set by the | |
564 | * data sender to indicate that the end-points of the | |
565 | * transport protocol are ECN-capable." | |
566 | * | |
567 | * Now setting the ECT bit all the time, as it should not cause | |
568 | * any problems protocol-wise even if our peer ignores it. | |
569 | * | |
570 | * Note: The works for IPv6 layer checks this bit too later | |
571 | * in transmission. See IP6_ECN_flow_xmit(). | |
572 | */ | |
b9031d9d | 573 | (*tp->af_specific->ecn_capable)(nskb->sk); |
1da177e4 LT |
574 | |
575 | /* Set up the IP options. */ | |
576 | /* BUG: not implemented | |
577 | * For v4 this all lives somewhere in sk->sk_opt... | |
578 | */ | |
579 | ||
580 | /* Dump that on IP! */ | |
196d6759 MB |
581 | if (asoc) { |
582 | asoc->stats.opackets++; | |
583 | if (asoc->peer.last_sent_to != tp) | |
584 | /* Considering the multiple CPU scenario, this is a | |
585 | * "correcter" place for last_sent_to. --xguo | |
586 | */ | |
587 | asoc->peer.last_sent_to = tp; | |
1da177e4 LT |
588 | } |
589 | ||
590 | if (has_data) { | |
591 | struct timer_list *timer; | |
592 | unsigned long timeout; | |
593 | ||
1da177e4 LT |
594 | /* Restart the AUTOCLOSE timer when sending data. */ |
595 | if (sctp_state(asoc, ESTABLISHED) && asoc->autoclose) { | |
596 | timer = &asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]; | |
597 | timeout = asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]; | |
598 | ||
599 | if (!mod_timer(timer, jiffies + timeout)) | |
600 | sctp_association_hold(asoc); | |
601 | } | |
602 | } | |
603 | ||
bb33381d | 604 | pr_debug("***sctp_transmit_packet*** skb->len:%d\n", nskb->len); |
1da177e4 | 605 | |
f880374c HX |
606 | nskb->local_df = packet->ipfragok; |
607 | (*tp->af_specific->sctp_xmit)(nskb, tp); | |
1da177e4 LT |
608 | |
609 | out: | |
d521c08f | 610 | sctp_packet_reset(packet); |
1da177e4 LT |
611 | return err; |
612 | no_route: | |
613 | kfree_skb(nskb); | |
b01a2407 | 614 | IP_INC_STATS_BH(sock_net(asoc->base.sk), IPSTATS_MIB_OUTNOROUTES); |
1da177e4 LT |
615 | |
616 | /* FIXME: Returning the 'err' will effect all the associations | |
617 | * associated with a socket, although only one of the paths of the | |
618 | * association is unreachable. | |
619 | * The real failure of a transport or association can be passed on | |
620 | * to the user via notifications. So setting this error may not be | |
621 | * required. | |
622 | */ | |
623 | /* err = -EHOSTUNREACH; */ | |
624 | err: | |
625 | /* Control chunks are unreliable so just drop them. DATA chunks | |
626 | * will get resent or dropped later. | |
627 | */ | |
628 | ||
79af02c2 DM |
629 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
630 | list_del_init(&chunk->list); | |
1da177e4 | 631 | if (!sctp_chunk_is_data(chunk)) |
d808ad9a | 632 | sctp_chunk_free(chunk); |
1da177e4 LT |
633 | } |
634 | goto out; | |
635 | nomem: | |
636 | err = -ENOMEM; | |
637 | goto err; | |
638 | } | |
639 | ||
640 | /******************************************************************** | |
641 | * 2nd Level Abstractions | |
642 | ********************************************************************/ | |
643 | ||
e83963b7 VY |
644 | /* This private function check to see if a chunk can be added */ |
645 | static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet, | |
1da177e4 LT |
646 | struct sctp_chunk *chunk) |
647 | { | |
648 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
e83963b7 | 649 | size_t datasize, rwnd, inflight, flight_size; |
1da177e4 | 650 | struct sctp_transport *transport = packet->transport; |
1da177e4 | 651 | struct sctp_association *asoc = transport->asoc; |
1da177e4 LT |
652 | struct sctp_outq *q = &asoc->outqueue; |
653 | ||
654 | /* RFC 2960 6.1 Transmission of DATA Chunks | |
655 | * | |
656 | * A) At any given time, the data sender MUST NOT transmit new data to | |
657 | * any destination transport address if its peer's rwnd indicates | |
658 | * that the peer has no buffer space (i.e. rwnd is 0, see Section | |
659 | * 6.2.1). However, regardless of the value of rwnd (including if it | |
660 | * is 0), the data sender can always have one DATA chunk in flight to | |
661 | * the receiver if allowed by cwnd (see rule B below). This rule | |
662 | * allows the sender to probe for a change in rwnd that the sender | |
663 | * missed due to the SACK having been lost in transit from the data | |
664 | * receiver to the data sender. | |
665 | */ | |
666 | ||
667 | rwnd = asoc->peer.rwnd; | |
e83963b7 VY |
668 | inflight = q->outstanding_bytes; |
669 | flight_size = transport->flight_size; | |
1da177e4 LT |
670 | |
671 | datasize = sctp_data_size(chunk); | |
672 | ||
673 | if (datasize > rwnd) { | |
674 | if (inflight > 0) { | |
675 | /* We have (at least) one data chunk in flight, | |
676 | * so we can't fall back to rule 6.1 B). | |
677 | */ | |
678 | retval = SCTP_XMIT_RWND_FULL; | |
679 | goto finish; | |
680 | } | |
681 | } | |
682 | ||
1da177e4 LT |
683 | /* RFC 2960 6.1 Transmission of DATA Chunks |
684 | * | |
685 | * B) At any given time, the sender MUST NOT transmit new data | |
686 | * to a given transport address if it has cwnd or more bytes | |
687 | * of data outstanding to that transport address. | |
688 | */ | |
689 | /* RFC 7.2.4 & the Implementers Guide 2.8. | |
690 | * | |
691 | * 3) ... | |
692 | * When a Fast Retransmit is being performed the sender SHOULD | |
693 | * ignore the value of cwnd and SHOULD NOT delay retransmission. | |
694 | */ | |
c226ef9b | 695 | if (chunk->fast_retransmit != SCTP_NEED_FRTX) |
e83963b7 | 696 | if (flight_size >= transport->cwnd) { |
1da177e4 LT |
697 | retval = SCTP_XMIT_RWND_FULL; |
698 | goto finish; | |
699 | } | |
700 | ||
701 | /* Nagle's algorithm to solve small-packet problem: | |
702 | * Inhibit the sending of new chunks when new outgoing data arrives | |
703 | * if any previously transmitted data on the connection remains | |
704 | * unacknowledged. | |
705 | */ | |
e83963b7 VY |
706 | if (!sctp_sk(asoc->base.sk)->nodelay && sctp_packet_empty(packet) && |
707 | inflight && sctp_state(asoc, ESTABLISHED)) { | |
95c96174 ED |
708 | unsigned int max = transport->pathmtu - packet->overhead; |
709 | unsigned int len = chunk->skb->len + q->out_qlen; | |
1da177e4 LT |
710 | |
711 | /* Check whether this chunk and all the rest of pending | |
712 | * data will fit or delay in hopes of bundling a full | |
713 | * sized packet. | |
cb95ea32 VY |
714 | * Don't delay large message writes that may have been |
715 | * fragmeneted into small peices. | |
1da177e4 | 716 | */ |
0e3aef8d | 717 | if ((len < max) && chunk->msg->can_delay) { |
1da177e4 LT |
718 | retval = SCTP_XMIT_NAGLE_DELAY; |
719 | goto finish; | |
720 | } | |
721 | } | |
722 | ||
e83963b7 VY |
723 | finish: |
724 | return retval; | |
725 | } | |
726 | ||
727 | /* This private function does management things when adding DATA chunk */ | |
728 | static void sctp_packet_append_data(struct sctp_packet *packet, | |
729 | struct sctp_chunk *chunk) | |
730 | { | |
731 | struct sctp_transport *transport = packet->transport; | |
732 | size_t datasize = sctp_data_size(chunk); | |
733 | struct sctp_association *asoc = transport->asoc; | |
734 | u32 rwnd = asoc->peer.rwnd; | |
735 | ||
1da177e4 LT |
736 | /* Keep track of how many bytes are in flight over this transport. */ |
737 | transport->flight_size += datasize; | |
738 | ||
739 | /* Keep track of how many bytes are in flight to the receiver. */ | |
740 | asoc->outqueue.outstanding_bytes += datasize; | |
741 | ||
a76c0adf | 742 | /* Update our view of the receiver's rwnd. */ |
1da177e4 LT |
743 | if (datasize < rwnd) |
744 | rwnd -= datasize; | |
745 | else | |
746 | rwnd = 0; | |
747 | ||
748 | asoc->peer.rwnd = rwnd; | |
749 | /* Has been accepted for transmission. */ | |
750 | if (!asoc->peer.prsctp_capable) | |
751 | chunk->msg->can_abandon = 0; | |
d8dd1578 NH |
752 | sctp_chunk_assign_tsn(chunk); |
753 | sctp_chunk_assign_ssn(chunk); | |
e83963b7 VY |
754 | } |
755 | ||
756 | static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet, | |
757 | struct sctp_chunk *chunk, | |
758 | u16 chunk_len) | |
759 | { | |
760 | size_t psize; | |
761 | size_t pmtu; | |
762 | int too_big; | |
763 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
764 | ||
765 | psize = packet->size; | |
766 | pmtu = ((packet->transport->asoc) ? | |
767 | (packet->transport->asoc->pathmtu) : | |
768 | (packet->transport->pathmtu)); | |
769 | ||
770 | too_big = (psize + chunk_len > pmtu); | |
771 | ||
772 | /* Decide if we need to fragment or resubmit later. */ | |
773 | if (too_big) { | |
774 | /* It's OK to fragmet at IP level if any one of the following | |
775 | * is true: | |
776 | * 1. The packet is empty (meaning this chunk is greater | |
777 | * the MTU) | |
778 | * 2. The chunk we are adding is a control chunk | |
779 | * 3. The packet doesn't have any data in it yet and data | |
780 | * requires authentication. | |
781 | */ | |
782 | if (sctp_packet_empty(packet) || !sctp_chunk_is_data(chunk) || | |
783 | (!packet->has_data && chunk->auth)) { | |
784 | /* We no longer do re-fragmentation. | |
785 | * Just fragment at the IP layer, if we | |
786 | * actually hit this condition | |
787 | */ | |
788 | packet->ipfragok = 1; | |
789 | } else { | |
790 | retval = SCTP_XMIT_PMTU_FULL; | |
791 | } | |
792 | } | |
1da177e4 | 793 | |
1da177e4 LT |
794 | return retval; |
795 | } |