blob: be50aa234dcdea30a5c7986eaeaae3570f64a6e3 [file] [log] [blame]
Vlad Yasevich60c778b2008-01-11 09:57:09 -05001/* SCTP kernel implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -05006 * This file is part of the SCTP kernel implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
8 * These functions handle output processing.
9 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -050010 * This SCTP implementation is free software;
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * 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 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -050016 * This SCTP implementation is distributed in the hope that it
Linus Torvalds1da177e2005-04-16 15:20:36 -070017 * 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
Joe Perches145ce502010-08-24 13:21:08 +000044#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
45
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090053#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070054#include <net/inet_ecn.h>
Vlad Yasevich8d2f9e812009-03-21 13:41:09 -070055#include <net/ip.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070056#include <net/icmp.h>
Pavel Emelyanov7c73a6f2008-07-16 20:20:11 -070057#include <net/net_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Linus Torvalds1da177e2005-04-16 15:20:36 -070059#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>
Vlad Yasevich9ad09772007-12-16 14:06:41 -080064#include <net/sctp/checksum.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66/* Forward declarations for private helpers. */
Neil Hormaned106272012-07-02 09:59:24 +000067static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet,
68 struct sctp_chunk *chunk);
Vlad Yaseviche83963b2009-08-07 10:43:07 -040069static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 struct sctp_chunk *chunk);
Vlad Yaseviche83963b2009-08-07 10:43:07 -040071static void sctp_packet_append_data(struct sctp_packet *packet,
72 struct sctp_chunk *chunk);
73static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet,
74 struct sctp_chunk *chunk,
75 u16 chunk_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
Wei Yongjunbe297142009-09-04 14:34:06 +080077static 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070088/* Config a packet.
89 * This appears to be a followup set of initializations.
90 */
91struct sctp_packet *sctp_packet_config(struct sctp_packet *packet,
92 __u32 vtag, int ecn_capable)
93{
94 struct sctp_chunk *chunk = NULL;
95
Harvey Harrison0dc47872008-03-05 20:47:47 -080096 SCTP_DEBUG_PRINTK("%s: packet:%p vtag:0x%x\n", __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 packet, vtag);
98
99 packet->vtag = vtag;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
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
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900105 * any other chunks get appended.
106 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 if (chunk)
108 sctp_packet_append_chunk(packet, chunk);
109 }
110
111 return packet;
112}
113
114/* Initialize the packet structure. */
115struct 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
Harvey Harrison0dc47872008-03-05 20:47:47 -0800122 SCTP_DEBUG_PRINTK("%s: packet:%p transport:%p\n", __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 packet, transport);
124
125 packet->transport = transport;
126 packet->source_port = sport;
127 packet->destination_port = dport;
David S. Miller79af02c2005-07-08 21:47:49 -0700128 INIT_LIST_HEAD(&packet->chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 if (asoc) {
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900130 struct sctp_sock *sp = sctp_sk(asoc->base.sk);
131 overhead = sp->pf->af->net_header_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 } else {
133 overhead = sizeof(struct ipv6hdr);
134 }
135 overhead += sizeof(struct sctphdr);
136 packet->overhead = overhead;
Wei Yongjunbe297142009-09-04 14:34:06 +0800137 sctp_packet_reset(packet);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 packet->vtag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 packet->malloced = 0;
140 return packet;
141}
142
143/* Free a packet. */
144void sctp_packet_free(struct sctp_packet *packet)
145{
David S. Miller79af02c2005-07-08 21:47:49 -0700146 struct sctp_chunk *chunk, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147
Harvey Harrison0dc47872008-03-05 20:47:47 -0800148 SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149
David S. Miller79af02c2005-07-08 21:47:49 -0700150 list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
151 list_del_init(&chunk->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 sctp_chunk_free(chunk);
David S. Miller79af02c2005-07-08 21:47:49 -0700153 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154
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 */
166sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *packet,
Vlad Yasevich2e3216c2008-06-19 16:08:18 -0700167 struct sctp_chunk *chunk,
168 int one_packet)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169{
170 sctp_xmit_t retval;
171 int error = 0;
172
Harvey Harrison0dc47872008-03-05 20:47:47 -0800173 SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 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 */
Vlad Yasevich2e3216c2008-06-19 16:08:18 -0700186 if (!one_packet)
187 retval = sctp_packet_append_chunk(packet,
188 chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 }
190 break;
191
192 case SCTP_XMIT_RWND_FULL:
193 case SCTP_XMIT_OK:
194 case SCTP_XMIT_NAGLE_DELAY:
195 break;
Stephen Hemminger3ff50b72007-04-20 17:09:22 -0700196 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
198 return retval;
199}
200
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700201/* Try to bundle an auth chunk into the packet. */
202static 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 */
Vlad Yasevich4007cc82009-09-04 18:21:00 -0400216 if (chunk->chunk_hdr->type == SCTP_CID_AUTH || pkt->has_auth)
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700217 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
Neil Hormaned106272012-07-02 09:59:24 +0000229 retval = __sctp_packet_append_chunk(pkt, auth);
230
231 if (retval != SCTP_XMIT_OK)
232 sctp_chunk_free(auth);
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700233
234 return retval;
235}
236
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237/* Try to bundle a SACK with the packet. */
238static 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;
Doug Grahamaf87b822009-07-29 12:05:57 -0400249 struct timer_list *timer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 asoc = pkt->transport->asoc;
Doug Grahamaf87b822009-07-29 12:05:57 -0400251 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252
Doug Grahamaf87b822009-07-29 12:05:57 -0400253 /* If the SACK timer is running, we have a pending SACK */
254 if (timer_pending(timer)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 struct sctp_chunk *sack;
Neil Horman42448542012-06-30 03:04:26 +0000256
257 if (pkt->transport->sack_generation !=
258 pkt->transport->asoc->peer.sack_generation)
259 return retval;
260
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 asoc->a_rwnd = asoc->rwnd;
262 sack = sctp_make_sack(asoc);
263 if (sack) {
Neil Hormaned106272012-07-02 09:59:24 +0000264 retval = __sctp_packet_append_chunk(pkt, sack);
265 if (retval != SCTP_XMIT_OK) {
266 sctp_chunk_free(sack);
267 goto out;
268 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 asoc->peer.sack_needed = 0;
Doug Grahamaf87b822009-07-29 12:05:57 -0400270 if (del_timer(timer))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 sctp_association_put(asoc);
272 }
273 }
274 }
Neil Hormaned106272012-07-02 09:59:24 +0000275out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 return retval;
277}
278
Neil Hormaned106272012-07-02 09:59:24 +0000279
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280/* Append a chunk to the offered packet reporting back any inability to do
281 * so.
282 */
Neil Hormaned106272012-07-02 09:59:24 +0000283static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet,
284 struct sctp_chunk *chunk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285{
286 sctp_xmit_t retval = SCTP_XMIT_OK;
287 __u16 chunk_len = WORD_ROUND(ntohs(chunk->chunk_hdr->length));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400289 /* 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400294 /* We believe that this chunk is OK to add to the packet */
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700295 switch (chunk->chunk_hdr->type) {
296 case SCTP_CID_DATA:
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400297 /* Account for the data being in the packet */
298 sctp_packet_append_data(packet, chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299 /* Disallow SACK bundling after DATA. */
300 packet->has_sack = 1;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700301 /* 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;
Vlad Yasevich759af002009-01-22 14:53:01 -0800305 /* timestamp the chunk for rtx purposes */
306 chunk->sent_at = jiffies;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700307 break;
308 case SCTP_CID_COOKIE_ECHO:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309 packet->has_cookie_echo = 1;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700310 break;
311
312 case SCTP_CID_SACK:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 packet->has_sack = 1;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700314 break;
315
316 case SCTP_CID_AUTH:
317 packet->has_auth = 1;
318 packet->auth = chunk;
319 break;
320 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
322 /* It is OK to send this chunk. */
David S. Miller79af02c2005-07-08 21:47:49 -0700323 list_add_tail(&chunk->list, &packet->chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 packet->size += chunk_len;
325 chunk->transport = packet->transport;
326finish:
327 return retval;
328}
329
Neil Hormaned106272012-07-02 09:59:24 +0000330/* Append a chunk to the offered packet reporting back any inability to do
331 * so.
332 */
333sctp_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
363finish:
364 return retval;
365}
366
Thomas Graf4c3a5bd2012-09-03 04:27:42 +0000367static void sctp_packet_release_owner(struct sk_buff *skb)
368{
369 sk_free(skb->sk);
370}
371
372static 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386/* 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 */
391int 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 struct sk_buff *nskb;
David S. Miller79af02c2005-07-08 21:47:49 -0700397 struct sctp_chunk *chunk, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 struct sock *sk;
399 int err = 0;
400 int padding; /* How much padding do we need? */
401 __u8 has_data = 0;
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700402 struct dst_entry *dst = tp->dst;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700403 unsigned char *auth = NULL; /* pointer to auth in skb data */
404 __u32 cksum_buf_len = sizeof(struct sctphdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405
Harvey Harrison0dc47872008-03-05 20:47:47 -0800406 SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700407
408 /* Do NOT generate a chunkless packet. */
David S. Miller79af02c2005-07-08 21:47:49 -0700409 if (list_empty(&packet->chunk_list))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 return err;
411
412 /* Set up convenience variables... */
David S. Miller79af02c2005-07-08 21:47:49 -0700413 chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 sk = chunk->skb->sk;
415
416 /* Allocate the new skb. */
Sridhar Samudrala594ccc12005-04-28 12:00:23 -0700417 nskb = alloc_skb(packet->size + LL_MAX_HEADER, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 if (!nskb)
419 goto nomem;
420
421 /* Make sure the outbound skb has enough header room reserved. */
Sridhar Samudrala594ccc12005-04-28 12:00:23 -0700422 skb_reserve(nskb, packet->overhead + LL_MAX_HEADER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423
424 /* Set the owning socket so that we know where to get the
425 * destination IP address.
426 */
Thomas Graf4c3a5bd2012-09-03 04:27:42 +0000427 sctp_packet_set_owner_w(nskb, sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428
Nicolas Dichtele0268862012-05-04 05:24:54 +0000429 if (!sctp_transport_dst_check(tp)) {
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700430 sctp_transport_route(tp, NULL, sctp_sk(sk));
431 if (asoc && (asoc->param_flags & SPP_PMTUD_ENABLE)) {
David S. Miller02f3d4c2012-07-16 03:57:14 -0700432 sctp_assoc_sync_pmtu(sk, asoc);
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700433 }
434 }
Eric Dumazetadf30902009-06-02 05:19:30 +0000435 dst = dst_clone(tp->dst);
436 skb_dst_set(nskb, dst);
Wei Yongjunff0ac742009-06-28 22:49:37 +0000437 if (!dst)
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700438 goto no_route;
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700439
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 /* Build the SCTP header. */
441 sh = (struct sctphdr *)skb_push(nskb, sizeof(struct sctphdr));
Jesse Brandeburg8dc92f72009-04-27 22:35:52 +0000442 skb_reset_transport_header(nskb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457 /**
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");
David S. Miller79af02c2005-07-08 21:47:49 -0700477 list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
478 list_del_init(&chunk->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 if (sctp_chunk_is_data(chunk)) {
Vlad Yasevichae19c542010-04-30 22:41:09 -0400480 /* 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486
Vlad Yasevichae19c542010-04-30 22:41:09 -0400487 if (!tp->rto_pending) {
488 chunk->rtt_in_progress = 1;
489 tp->rto_pending = 1;
Neil Hormand8dd1572009-11-23 15:54:00 -0500490 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 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
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700498 /* 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),
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700507 chunk->skb->data, chunk->skb->len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508
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))
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900526 sctp_chunk_free(chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527 }
528
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700529 /* 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 */
Michał Mirosławb73c43f2011-07-13 14:10:29 +0000550 if (!sctp_checksum_disable) {
551 if (!(dst->dev->features & NETIF_F_SCTP_CSUM)) {
552 __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
Vlad Yasevich4458f042009-02-13 08:33:42 +0000553
Michał Mirosławb73c43f2011-07-13 14:10:29 +0000554 /* 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 {
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300559 /* no need to seed pseudo checksum for SCTP */
Jesse Brandeburg8dc92f72009-04-27 22:35:52 +0000560 nskb->ip_summed = CHECKSUM_PARTIAL;
561 nskb->csum_start = (skb_transport_header(nskb) -
562 nskb->head);
563 nskb->csum_offset = offsetof(struct sctphdr, checksum);
Jesse Brandeburg8dc92f72009-04-27 22:35:52 +0000564 }
565 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 /* 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 */
Vlad Yasevichb9031d92008-06-04 12:40:15 -0700579 (*tp->af_specific->ecn_capable)(nskb->sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 /* 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608 SCTP_DEBUG_PRINTK("***sctp_transmit_packet*** skb len %d\n",
609 nskb->len);
610
Herbert Xuf8803742008-08-03 21:15:08 -0700611 nskb->local_df = packet->ipfragok;
612 (*tp->af_specific->sctp_xmit)(nskb, tp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613
614out:
Wei Yongjund521c082009-09-02 13:05:33 +0800615 sctp_packet_reset(packet);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 return err;
617no_route:
618 kfree_skb(nskb);
Pavel Emelyanov7c73a6f2008-07-16 20:20:11 -0700619 IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620
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; */
629err:
630 /* Control chunks are unreliable so just drop them. DATA chunks
631 * will get resent or dropped later.
632 */
633
David S. Miller79af02c2005-07-08 21:47:49 -0700634 list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
635 list_del_init(&chunk->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 if (!sctp_chunk_is_data(chunk))
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900637 sctp_chunk_free(chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 }
639 goto out;
640nomem:
641 err = -ENOMEM;
642 goto err;
643}
644
645/********************************************************************
646 * 2nd Level Abstractions
647 ********************************************************************/
648
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400649/* This private function check to see if a chunk can be added */
650static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 struct sctp_chunk *chunk)
652{
653 sctp_xmit_t retval = SCTP_XMIT_OK;
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400654 size_t datasize, rwnd, inflight, flight_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 struct sctp_transport *transport = packet->transport;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 struct sctp_association *asoc = transport->asoc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 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;
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400673 inflight = q->outstanding_bytes;
674 flight_size = transport->flight_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 /* 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 */
Neil Hormanc226ef92008-07-25 12:44:09 -0400700 if (chunk->fast_retransmit != SCTP_NEED_FRTX)
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400701 if (flight_size >= transport->cwnd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 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 */
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400711 if (!sctp_sk(asoc->base.sk)->nodelay && sctp_packet_empty(packet) &&
712 inflight && sctp_state(asoc, ESTABLISHED)) {
Eric Dumazet95c96172012-04-15 05:58:06 +0000713 unsigned int max = transport->pathmtu - packet->overhead;
714 unsigned int len = chunk->skb->len + q->out_qlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715
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.
Vlad Yasevichcb95ea32009-09-04 18:20:59 -0400719 * Don't delay large message writes that may have been
720 * fragmeneted into small peices.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721 */
Vlad Yasevich0e3aef82010-04-30 22:41:10 -0400722 if ((len < max) && chunk->msg->can_delay) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 retval = SCTP_XMIT_NAGLE_DELAY;
724 goto finish;
725 }
726 }
727
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400728finish:
729 return retval;
730}
731
732/* This private function does management things when adding DATA chunk */
733static 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 /* 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
Thomas Grafa76c0ad2011-12-19 04:11:40 +0000747 /* Update our view of the receiver's rwnd. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 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;
Neil Hormand8dd1572009-11-23 15:54:00 -0500757 sctp_chunk_assign_tsn(chunk);
758 sctp_chunk_assign_ssn(chunk);
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400759}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400761static 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 }
798
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 return retval;
800}