blob: 7c5589363433c38d6c63a344f36d5e9d61befc45 [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
44#include <linux/types.h>
45#include <linux/kernel.h>
46#include <linux/wait.h>
47#include <linux/time.h>
48#include <linux/ip.h>
49#include <linux/ipv6.h>
50#include <linux/init.h>
51#include <net/inet_ecn.h>
Vlad Yasevich8d2f9e82009-03-21 13:41:09 -070052#include <net/ip.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070053#include <net/icmp.h>
Pavel Emelyanov7c73a6f2008-07-16 20:20:11 -070054#include <net/net_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
Linus Torvalds1da177e2005-04-16 15:20:36 -070056#include <linux/socket.h> /* for sa_family_t */
57#include <net/sock.h>
58
59#include <net/sctp/sctp.h>
60#include <net/sctp/sm.h>
Vlad Yasevich9ad09772007-12-16 14:06:41 -080061#include <net/sctp/checksum.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63/* Forward declarations for private helpers. */
Vlad Yaseviche83963b2009-08-07 10:43:07 -040064static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 struct sctp_chunk *chunk);
Vlad Yaseviche83963b2009-08-07 10:43:07 -040066static void sctp_packet_append_data(struct sctp_packet *packet,
67 struct sctp_chunk *chunk);
68static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet,
69 struct sctp_chunk *chunk,
70 u16 chunk_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
Wei Yongjunbe297142009-09-04 14:34:06 +080072static void sctp_packet_reset(struct sctp_packet *packet)
73{
74 packet->size = packet->overhead;
75 packet->has_cookie_echo = 0;
76 packet->has_sack = 0;
77 packet->has_data = 0;
78 packet->has_auth = 0;
79 packet->ipfragok = 0;
80 packet->auth = NULL;
81}
82
Linus Torvalds1da177e2005-04-16 15:20:36 -070083/* Config a packet.
84 * This appears to be a followup set of initializations.
85 */
86struct sctp_packet *sctp_packet_config(struct sctp_packet *packet,
87 __u32 vtag, int ecn_capable)
88{
89 struct sctp_chunk *chunk = NULL;
90
Harvey Harrison0dc47872008-03-05 20:47:47 -080091 SCTP_DEBUG_PRINTK("%s: packet:%p vtag:0x%x\n", __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 packet, vtag);
93
Wei Yongjunbe297142009-09-04 14:34:06 +080094 sctp_packet_reset(packet);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 packet->vtag = vtag;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97 if (ecn_capable && sctp_packet_empty(packet)) {
98 chunk = sctp_get_ecne_prepend(packet->transport->asoc);
99
100 /* If there a is a prepend chunk stick it on the list before
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900101 * any other chunks get appended.
102 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 if (chunk)
104 sctp_packet_append_chunk(packet, chunk);
105 }
106
107 return packet;
108}
109
110/* Initialize the packet structure. */
111struct sctp_packet *sctp_packet_init(struct sctp_packet *packet,
112 struct sctp_transport *transport,
113 __u16 sport, __u16 dport)
114{
115 struct sctp_association *asoc = transport->asoc;
116 size_t overhead;
117
Harvey Harrison0dc47872008-03-05 20:47:47 -0800118 SCTP_DEBUG_PRINTK("%s: packet:%p transport:%p\n", __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 packet, transport);
120
121 packet->transport = transport;
122 packet->source_port = sport;
123 packet->destination_port = dport;
David S. Miller79af02c2005-07-08 21:47:49 -0700124 INIT_LIST_HEAD(&packet->chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 if (asoc) {
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900126 struct sctp_sock *sp = sctp_sk(asoc->base.sk);
127 overhead = sp->pf->af->net_header_len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 } else {
129 overhead = sizeof(struct ipv6hdr);
130 }
131 overhead += sizeof(struct sctphdr);
132 packet->overhead = overhead;
Wei Yongjunbe297142009-09-04 14:34:06 +0800133 sctp_packet_reset(packet);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 packet->vtag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 packet->malloced = 0;
136 return packet;
137}
138
139/* Free a packet. */
140void sctp_packet_free(struct sctp_packet *packet)
141{
David S. Miller79af02c2005-07-08 21:47:49 -0700142 struct sctp_chunk *chunk, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Harvey Harrison0dc47872008-03-05 20:47:47 -0800144 SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
David S. Miller79af02c2005-07-08 21:47:49 -0700146 list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
147 list_del_init(&chunk->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 sctp_chunk_free(chunk);
David S. Miller79af02c2005-07-08 21:47:49 -0700149 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
151 if (packet->malloced)
152 kfree(packet);
153}
154
155/* This routine tries to append the chunk to the offered packet. If adding
156 * the chunk causes the packet to exceed the path MTU and COOKIE_ECHO chunk
157 * is not present in the packet, it transmits the input packet.
158 * Data can be bundled with a packet containing a COOKIE_ECHO chunk as long
159 * as it can fit in the packet, but any more data that does not fit in this
160 * packet can be sent only after receiving the COOKIE_ACK.
161 */
162sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *packet,
Vlad Yasevich2e3216c2008-06-19 16:08:18 -0700163 struct sctp_chunk *chunk,
164 int one_packet)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165{
166 sctp_xmit_t retval;
167 int error = 0;
168
Harvey Harrison0dc47872008-03-05 20:47:47 -0800169 SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 packet, chunk);
171
172 switch ((retval = (sctp_packet_append_chunk(packet, chunk)))) {
173 case SCTP_XMIT_PMTU_FULL:
174 if (!packet->has_cookie_echo) {
175 error = sctp_packet_transmit(packet);
176 if (error < 0)
177 chunk->skb->sk->sk_err = -error;
178
179 /* If we have an empty packet, then we can NOT ever
180 * return PMTU_FULL.
181 */
Vlad Yasevich2e3216c2008-06-19 16:08:18 -0700182 if (!one_packet)
183 retval = sctp_packet_append_chunk(packet,
184 chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 }
186 break;
187
188 case SCTP_XMIT_RWND_FULL:
189 case SCTP_XMIT_OK:
190 case SCTP_XMIT_NAGLE_DELAY:
191 break;
Stephen Hemminger3ff50b72007-04-20 17:09:22 -0700192 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
194 return retval;
195}
196
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700197/* Try to bundle an auth chunk into the packet. */
198static sctp_xmit_t sctp_packet_bundle_auth(struct sctp_packet *pkt,
199 struct sctp_chunk *chunk)
200{
201 struct sctp_association *asoc = pkt->transport->asoc;
202 struct sctp_chunk *auth;
203 sctp_xmit_t retval = SCTP_XMIT_OK;
204
205 /* if we don't have an association, we can't do authentication */
206 if (!asoc)
207 return retval;
208
209 /* See if this is an auth chunk we are bundling or if
210 * auth is already bundled.
211 */
Vlad Yasevich4007cc82009-09-04 18:21:00 -0400212 if (chunk->chunk_hdr->type == SCTP_CID_AUTH || pkt->has_auth)
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700213 return retval;
214
215 /* if the peer did not request this chunk to be authenticated,
216 * don't do it
217 */
218 if (!chunk->auth)
219 return retval;
220
221 auth = sctp_make_auth(asoc);
222 if (!auth)
223 return retval;
224
225 retval = sctp_packet_append_chunk(pkt, auth);
226
227 return retval;
228}
229
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230/* Try to bundle a SACK with the packet. */
231static sctp_xmit_t sctp_packet_bundle_sack(struct sctp_packet *pkt,
232 struct sctp_chunk *chunk)
233{
234 sctp_xmit_t retval = SCTP_XMIT_OK;
235
236 /* If sending DATA and haven't aleady bundled a SACK, try to
237 * bundle one in to the packet.
238 */
239 if (sctp_chunk_is_data(chunk) && !pkt->has_sack &&
240 !pkt->has_cookie_echo) {
241 struct sctp_association *asoc;
Doug Grahamaf87b822009-07-29 12:05:57 -0400242 struct timer_list *timer;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 asoc = pkt->transport->asoc;
Doug Grahamaf87b822009-07-29 12:05:57 -0400244 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245
Doug Grahamaf87b822009-07-29 12:05:57 -0400246 /* If the SACK timer is running, we have a pending SACK */
247 if (timer_pending(timer)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 struct sctp_chunk *sack;
249 asoc->a_rwnd = asoc->rwnd;
250 sack = sctp_make_sack(asoc);
251 if (sack) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 retval = sctp_packet_append_chunk(pkt, sack);
253 asoc->peer.sack_needed = 0;
Doug Grahamaf87b822009-07-29 12:05:57 -0400254 if (del_timer(timer))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 sctp_association_put(asoc);
256 }
257 }
258 }
259 return retval;
260}
261
262/* Append a chunk to the offered packet reporting back any inability to do
263 * so.
264 */
265sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *packet,
266 struct sctp_chunk *chunk)
267{
268 sctp_xmit_t retval = SCTP_XMIT_OK;
269 __u16 chunk_len = WORD_ROUND(ntohs(chunk->chunk_hdr->length));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270
Harvey Harrison0dc47872008-03-05 20:47:47 -0800271 SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__, packet,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272 chunk);
273
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400274 /* Data chunks are special. Before seeing what else we can
275 * bundle into this packet, check to see if we are allowed to
276 * send this DATA.
277 */
278 if (sctp_chunk_is_data(chunk)) {
279 retval = sctp_packet_can_append_data(packet, chunk);
280 if (retval != SCTP_XMIT_OK)
281 goto finish;
282 }
283
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700284 /* Try to bundle AUTH chunk */
285 retval = sctp_packet_bundle_auth(packet, chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286 if (retval != SCTP_XMIT_OK)
287 goto finish;
288
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700289 /* Try to bundle SACK chunk */
290 retval = sctp_packet_bundle_sack(packet, chunk);
291 if (retval != SCTP_XMIT_OK)
292 goto finish;
293
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400294 /* Check to see if this chunk will fit into the packet */
295 retval = sctp_packet_will_fit(packet, chunk, chunk_len);
296 if (retval != SCTP_XMIT_OK)
297 goto finish;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400299 /* We believe that this chunk is OK to add to the packet */
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700300 switch (chunk->chunk_hdr->type) {
301 case SCTP_CID_DATA:
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400302 /* Account for the data being in the packet */
303 sctp_packet_append_data(packet, chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 /* Disallow SACK bundling after DATA. */
305 packet->has_sack = 1;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700306 /* Disallow AUTH bundling after DATA */
307 packet->has_auth = 1;
308 /* Let it be knows that packet has DATA in it */
309 packet->has_data = 1;
Vlad Yasevich759af002009-01-22 14:53:01 -0800310 /* timestamp the chunk for rtx purposes */
311 chunk->sent_at = jiffies;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700312 break;
313 case SCTP_CID_COOKIE_ECHO:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 packet->has_cookie_echo = 1;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700315 break;
316
317 case SCTP_CID_SACK:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 packet->has_sack = 1;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700319 break;
320
321 case SCTP_CID_AUTH:
322 packet->has_auth = 1;
323 packet->auth = chunk;
324 break;
325 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
327 /* It is OK to send this chunk. */
David S. Miller79af02c2005-07-08 21:47:49 -0700328 list_add_tail(&chunk->list, &packet->chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329 packet->size += chunk_len;
330 chunk->transport = packet->transport;
331finish:
332 return retval;
333}
334
335/* All packets are sent to the network through this function from
336 * sctp_outq_tail().
337 *
338 * The return value is a normal kernel error return value.
339 */
340int sctp_packet_transmit(struct sctp_packet *packet)
341{
342 struct sctp_transport *tp = packet->transport;
343 struct sctp_association *asoc = tp->asoc;
344 struct sctphdr *sh;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 struct sk_buff *nskb;
David S. Miller79af02c2005-07-08 21:47:49 -0700346 struct sctp_chunk *chunk, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 struct sock *sk;
348 int err = 0;
349 int padding; /* How much padding do we need? */
350 __u8 has_data = 0;
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700351 struct dst_entry *dst = tp->dst;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700352 unsigned char *auth = NULL; /* pointer to auth in skb data */
353 __u32 cksum_buf_len = sizeof(struct sctphdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354
Harvey Harrison0dc47872008-03-05 20:47:47 -0800355 SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356
357 /* Do NOT generate a chunkless packet. */
David S. Miller79af02c2005-07-08 21:47:49 -0700358 if (list_empty(&packet->chunk_list))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 return err;
360
361 /* Set up convenience variables... */
David S. Miller79af02c2005-07-08 21:47:49 -0700362 chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 sk = chunk->skb->sk;
364
365 /* Allocate the new skb. */
Sridhar Samudrala594ccc12005-04-28 12:00:23 -0700366 nskb = alloc_skb(packet->size + LL_MAX_HEADER, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 if (!nskb)
368 goto nomem;
369
370 /* Make sure the outbound skb has enough header room reserved. */
Sridhar Samudrala594ccc12005-04-28 12:00:23 -0700371 skb_reserve(nskb, packet->overhead + LL_MAX_HEADER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372
373 /* Set the owning socket so that we know where to get the
374 * destination IP address.
375 */
376 skb_set_owner_w(nskb, sk);
377
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700378 /* The 'obsolete' field of dst is set to 2 when a dst is freed. */
379 if (!dst || (dst->obsolete > 1)) {
380 dst_release(dst);
381 sctp_transport_route(tp, NULL, sctp_sk(sk));
382 if (asoc && (asoc->param_flags & SPP_PMTUD_ENABLE)) {
383 sctp_assoc_sync_pmtu(asoc);
384 }
385 }
Eric Dumazetadf30902009-06-02 05:19:30 +0000386 dst = dst_clone(tp->dst);
387 skb_dst_set(nskb, dst);
Wei Yongjunff0ac742009-06-28 22:49:37 +0000388 if (!dst)
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700389 goto no_route;
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700390
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391 /* Build the SCTP header. */
392 sh = (struct sctphdr *)skb_push(nskb, sizeof(struct sctphdr));
Jesse Brandeburg8dc92f72009-04-27 22:35:52 +0000393 skb_reset_transport_header(nskb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394 sh->source = htons(packet->source_port);
395 sh->dest = htons(packet->destination_port);
396
397 /* From 6.8 Adler-32 Checksum Calculation:
398 * After the packet is constructed (containing the SCTP common
399 * header and one or more control or DATA chunks), the
400 * transmitter shall:
401 *
402 * 1) Fill in the proper Verification Tag in the SCTP common
403 * header and initialize the checksum field to 0's.
404 */
405 sh->vtag = htonl(packet->vtag);
406 sh->checksum = 0;
407
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 /**
409 * 6.10 Bundling
410 *
411 * An endpoint bundles chunks by simply including multiple
412 * chunks in one outbound SCTP packet. ...
413 */
414
415 /**
416 * 3.2 Chunk Field Descriptions
417 *
418 * The total length of a chunk (including Type, Length and
419 * Value fields) MUST be a multiple of 4 bytes. If the length
420 * of the chunk is not a multiple of 4 bytes, the sender MUST
421 * pad the chunk with all zero bytes and this padding is not
422 * included in the chunk length field. The sender should
423 * never pad with more than 3 bytes.
424 *
425 * [This whole comment explains WORD_ROUND() below.]
426 */
427 SCTP_DEBUG_PRINTK("***sctp_transmit_packet***\n");
David S. Miller79af02c2005-07-08 21:47:49 -0700428 list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
429 list_del_init(&chunk->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 if (sctp_chunk_is_data(chunk)) {
431
Neil Hormand8dd1572009-11-23 15:54:00 -0500432 if (!chunk->resent) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433
Neil Hormand8dd1572009-11-23 15:54:00 -0500434 /* 6.3.1 C4) When data is in flight and when allowed
435 * by rule C5, a new RTT measurement MUST be made each
436 * round trip. Furthermore, new RTT measurements
437 * SHOULD be made no more than once per round-trip
438 * for a given destination transport address.
439 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440
441 if (!tp->rto_pending) {
442 chunk->rtt_in_progress = 1;
443 tp->rto_pending = 1;
444 }
Neil Hormand8dd1572009-11-23 15:54:00 -0500445 }
446
447 chunk->resent = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 has_data = 1;
450 }
451
452 padding = WORD_ROUND(chunk->skb->len) - chunk->skb->len;
453 if (padding)
454 memset(skb_put(chunk->skb, padding), 0, padding);
455
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700456 /* if this is the auth chunk that we are adding,
457 * store pointer where it will be added and put
458 * the auth into the packet.
459 */
460 if (chunk == packet->auth)
461 auth = skb_tail_pointer(nskb);
462
463 cksum_buf_len += chunk->skb->len;
464 memcpy(skb_put(nskb, chunk->skb->len),
Sridhar Samudrala503b55f2006-06-17 22:57:28 -0700465 chunk->skb->data, chunk->skb->len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466
467 SCTP_DEBUG_PRINTK("%s %p[%s] %s 0x%x, %s %d, %s %d, %s %d\n",
468 "*** Chunk", chunk,
469 sctp_cname(SCTP_ST_CHUNK(
470 chunk->chunk_hdr->type)),
471 chunk->has_tsn ? "TSN" : "No TSN",
472 chunk->has_tsn ?
473 ntohl(chunk->subh.data_hdr->tsn) : 0,
474 "length", ntohs(chunk->chunk_hdr->length),
475 "chunk->skb->len", chunk->skb->len,
476 "rtt_in_progress", chunk->rtt_in_progress);
477
478 /*
479 * If this is a control chunk, this is our last
480 * reference. Free data chunks after they've been
481 * acknowledged or have failed.
482 */
483 if (!sctp_chunk_is_data(chunk))
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900484 sctp_chunk_free(chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 }
486
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700487 /* SCTP-AUTH, Section 6.2
488 * The sender MUST calculate the MAC as described in RFC2104 [2]
489 * using the hash function H as described by the MAC Identifier and
490 * the shared association key K based on the endpoint pair shared key
491 * described by the shared key identifier. The 'data' used for the
492 * computation of the AUTH-chunk is given by the AUTH chunk with its
493 * HMAC field set to zero (as shown in Figure 6) followed by all
494 * chunks that are placed after the AUTH chunk in the SCTP packet.
495 */
496 if (auth)
497 sctp_auth_calculate_hmac(asoc, nskb,
498 (struct sctp_auth_chunk *)auth,
499 GFP_ATOMIC);
500
501 /* 2) Calculate the Adler-32 checksum of the whole packet,
502 * including the SCTP common header and all the
503 * chunks.
504 *
505 * Note: Adler-32 is no longer applicable, as has been replaced
506 * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>.
507 */
Jesse Brandeburg8dc92f72009-04-27 22:35:52 +0000508 if (!sctp_checksum_disable &&
509 !(dst->dev->features & (NETIF_F_NO_CSUM | NETIF_F_SCTP_CSUM))) {
Vlad Yasevich4458f042009-02-13 08:33:42 +0000510 __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
511
512 /* 3) Put the resultant value into the checksum field in the
513 * common header, and leave the rest of the bits unchanged.
514 */
515 sh->checksum = sctp_end_cksum(crc32);
Jesse Brandeburg8dc92f72009-04-27 22:35:52 +0000516 } else {
517 if (dst->dev->features & NETIF_F_SCTP_CSUM) {
518 /* no need to seed psuedo checksum for SCTP */
519 nskb->ip_summed = CHECKSUM_PARTIAL;
520 nskb->csum_start = (skb_transport_header(nskb) -
521 nskb->head);
522 nskb->csum_offset = offsetof(struct sctphdr, checksum);
523 } else {
524 nskb->ip_summed = CHECKSUM_UNNECESSARY;
525 }
526 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 /* IP layer ECN support
529 * From RFC 2481
530 * "The ECN-Capable Transport (ECT) bit would be set by the
531 * data sender to indicate that the end-points of the
532 * transport protocol are ECN-capable."
533 *
534 * Now setting the ECT bit all the time, as it should not cause
535 * any problems protocol-wise even if our peer ignores it.
536 *
537 * Note: The works for IPv6 layer checks this bit too later
538 * in transmission. See IP6_ECN_flow_xmit().
539 */
Vlad Yasevichb9031d92008-06-04 12:40:15 -0700540 (*tp->af_specific->ecn_capable)(nskb->sk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541
542 /* Set up the IP options. */
543 /* BUG: not implemented
544 * For v4 this all lives somewhere in sk->sk_opt...
545 */
546
547 /* Dump that on IP! */
548 if (asoc && asoc->peer.last_sent_to != tp) {
549 /* Considering the multiple CPU scenario, this is a
550 * "correcter" place for last_sent_to. --xguo
551 */
552 asoc->peer.last_sent_to = tp;
553 }
554
555 if (has_data) {
556 struct timer_list *timer;
557 unsigned long timeout;
558
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 /* Restart the AUTOCLOSE timer when sending data. */
560 if (sctp_state(asoc, ESTABLISHED) && asoc->autoclose) {
561 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
562 timeout = asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE];
563
564 if (!mod_timer(timer, jiffies + timeout))
565 sctp_association_hold(asoc);
566 }
567 }
568
Linus Torvalds1da177e2005-04-16 15:20:36 -0700569 SCTP_DEBUG_PRINTK("***sctp_transmit_packet*** skb len %d\n",
570 nskb->len);
571
Herbert Xuf8803742008-08-03 21:15:08 -0700572 nskb->local_df = packet->ipfragok;
573 (*tp->af_specific->sctp_xmit)(nskb, tp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
575out:
Wei Yongjund521c082009-09-02 13:05:33 +0800576 sctp_packet_reset(packet);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700577 return err;
578no_route:
579 kfree_skb(nskb);
Pavel Emelyanov7c73a6f2008-07-16 20:20:11 -0700580 IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581
582 /* FIXME: Returning the 'err' will effect all the associations
583 * associated with a socket, although only one of the paths of the
584 * association is unreachable.
585 * The real failure of a transport or association can be passed on
586 * to the user via notifications. So setting this error may not be
587 * required.
588 */
589 /* err = -EHOSTUNREACH; */
590err:
591 /* Control chunks are unreliable so just drop them. DATA chunks
592 * will get resent or dropped later.
593 */
594
David S. Miller79af02c2005-07-08 21:47:49 -0700595 list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) {
596 list_del_init(&chunk->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 if (!sctp_chunk_is_data(chunk))
YOSHIFUJI Hideakid808ad92007-02-09 23:25:18 +0900598 sctp_chunk_free(chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 }
600 goto out;
601nomem:
602 err = -ENOMEM;
603 goto err;
604}
605
606/********************************************************************
607 * 2nd Level Abstractions
608 ********************************************************************/
609
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400610/* This private function check to see if a chunk can be added */
611static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 struct sctp_chunk *chunk)
613{
614 sctp_xmit_t retval = SCTP_XMIT_OK;
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400615 size_t datasize, rwnd, inflight, flight_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 struct sctp_transport *transport = packet->transport;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 struct sctp_association *asoc = transport->asoc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 struct sctp_outq *q = &asoc->outqueue;
619
620 /* RFC 2960 6.1 Transmission of DATA Chunks
621 *
622 * A) At any given time, the data sender MUST NOT transmit new data to
623 * any destination transport address if its peer's rwnd indicates
624 * that the peer has no buffer space (i.e. rwnd is 0, see Section
625 * 6.2.1). However, regardless of the value of rwnd (including if it
626 * is 0), the data sender can always have one DATA chunk in flight to
627 * the receiver if allowed by cwnd (see rule B below). This rule
628 * allows the sender to probe for a change in rwnd that the sender
629 * missed due to the SACK having been lost in transit from the data
630 * receiver to the data sender.
631 */
632
633 rwnd = asoc->peer.rwnd;
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400634 inflight = q->outstanding_bytes;
635 flight_size = transport->flight_size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636
637 datasize = sctp_data_size(chunk);
638
639 if (datasize > rwnd) {
640 if (inflight > 0) {
641 /* We have (at least) one data chunk in flight,
642 * so we can't fall back to rule 6.1 B).
643 */
644 retval = SCTP_XMIT_RWND_FULL;
645 goto finish;
646 }
647 }
648
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 /* RFC 2960 6.1 Transmission of DATA Chunks
650 *
651 * B) At any given time, the sender MUST NOT transmit new data
652 * to a given transport address if it has cwnd or more bytes
653 * of data outstanding to that transport address.
654 */
655 /* RFC 7.2.4 & the Implementers Guide 2.8.
656 *
657 * 3) ...
658 * When a Fast Retransmit is being performed the sender SHOULD
659 * ignore the value of cwnd and SHOULD NOT delay retransmission.
660 */
Neil Hormanc226ef92008-07-25 12:44:09 -0400661 if (chunk->fast_retransmit != SCTP_NEED_FRTX)
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400662 if (flight_size >= transport->cwnd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 retval = SCTP_XMIT_RWND_FULL;
664 goto finish;
665 }
666
667 /* Nagle's algorithm to solve small-packet problem:
668 * Inhibit the sending of new chunks when new outgoing data arrives
669 * if any previously transmitted data on the connection remains
670 * unacknowledged.
671 */
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400672 if (!sctp_sk(asoc->base.sk)->nodelay && sctp_packet_empty(packet) &&
673 inflight && sctp_state(asoc, ESTABLISHED)) {
Vlad Yasevichb29e7902009-09-04 18:20:59 -0400674 unsigned max = transport->pathmtu - packet->overhead;
675 unsigned len = chunk->skb->len + q->out_qlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676
677 /* Check whether this chunk and all the rest of pending
678 * data will fit or delay in hopes of bundling a full
679 * sized packet.
Vlad Yasevichcb95ea32009-09-04 18:20:59 -0400680 * Don't delay large message writes that may have been
681 * fragmeneted into small peices.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682 */
Vlad Yasevichcb95ea32009-09-04 18:20:59 -0400683 if ((len < max) && (chunk->msg->msg_size < max)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 retval = SCTP_XMIT_NAGLE_DELAY;
685 goto finish;
686 }
687 }
688
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400689finish:
690 return retval;
691}
692
693/* This private function does management things when adding DATA chunk */
694static void sctp_packet_append_data(struct sctp_packet *packet,
695 struct sctp_chunk *chunk)
696{
697 struct sctp_transport *transport = packet->transport;
698 size_t datasize = sctp_data_size(chunk);
699 struct sctp_association *asoc = transport->asoc;
700 u32 rwnd = asoc->peer.rwnd;
701
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 /* Keep track of how many bytes are in flight over this transport. */
703 transport->flight_size += datasize;
704
705 /* Keep track of how many bytes are in flight to the receiver. */
706 asoc->outqueue.outstanding_bytes += datasize;
707
Sridhar Samudralacd497882006-09-29 17:09:05 -0700708 /* Update our view of the receiver's rwnd. Include sk_buff overhead
709 * while updating peer.rwnd so that it reduces the chances of a
710 * receiver running out of receive buffer space even when receive
711 * window is still open. This can happen when a sender is sending
712 * sending small messages.
713 */
714 datasize += sizeof(struct sk_buff);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 if (datasize < rwnd)
716 rwnd -= datasize;
717 else
718 rwnd = 0;
719
720 asoc->peer.rwnd = rwnd;
721 /* Has been accepted for transmission. */
722 if (!asoc->peer.prsctp_capable)
723 chunk->msg->can_abandon = 0;
Neil Hormand8dd1572009-11-23 15:54:00 -0500724 sctp_chunk_assign_tsn(chunk);
725 sctp_chunk_assign_ssn(chunk);
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400726}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727
Vlad Yaseviche83963b2009-08-07 10:43:07 -0400728static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet,
729 struct sctp_chunk *chunk,
730 u16 chunk_len)
731{
732 size_t psize;
733 size_t pmtu;
734 int too_big;
735 sctp_xmit_t retval = SCTP_XMIT_OK;
736
737 psize = packet->size;
738 pmtu = ((packet->transport->asoc) ?
739 (packet->transport->asoc->pathmtu) :
740 (packet->transport->pathmtu));
741
742 too_big = (psize + chunk_len > pmtu);
743
744 /* Decide if we need to fragment or resubmit later. */
745 if (too_big) {
746 /* It's OK to fragmet at IP level if any one of the following
747 * is true:
748 * 1. The packet is empty (meaning this chunk is greater
749 * the MTU)
750 * 2. The chunk we are adding is a control chunk
751 * 3. The packet doesn't have any data in it yet and data
752 * requires authentication.
753 */
754 if (sctp_packet_empty(packet) || !sctp_chunk_is_data(chunk) ||
755 (!packet->has_data && chunk->auth)) {
756 /* We no longer do re-fragmentation.
757 * Just fragment at the IP layer, if we
758 * actually hit this condition
759 */
760 packet->ipfragok = 1;
761 } else {
762 retval = SCTP_XMIT_PMTU_FULL;
763 }
764 }
765
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 return retval;
767}