Commit | Line | Data |
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60c778b2 | 1 | /* SCTP kernel implementation |
1da177e4 LT |
2 | * (C) Copyright IBM Corp. 2001, 2004 |
3 | * Copyright (c) 1999-2000 Cisco, Inc. | |
4 | * Copyright (c) 1999-2001 Motorola, Inc. | |
5 | * | |
60c778b2 | 6 | * This file is part of the SCTP kernel implementation |
1da177e4 LT |
7 | * |
8 | * These functions handle output processing. | |
9 | * | |
60c778b2 | 10 | * This SCTP implementation is free software; |
1da177e4 LT |
11 | * you can redistribute it and/or modify it under the terms of |
12 | * the GNU General Public License as published by | |
13 | * the Free Software Foundation; either version 2, or (at your option) | |
14 | * any later version. | |
15 | * | |
60c778b2 | 16 | * This SCTP implementation is distributed in the hope that it |
1da177e4 LT |
17 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
18 | * ************************ | |
19 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
20 | * See the GNU General Public License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License | |
23 | * along with GNU CC; see the file COPYING. If not, write to | |
24 | * the Free Software Foundation, 59 Temple Place - Suite 330, | |
25 | * Boston, MA 02111-1307, USA. | |
26 | * | |
27 | * Please send any bug reports or fixes you make to the | |
28 | * email address(es): | |
29 | * lksctp developers <lksctp-developers@lists.sourceforge.net> | |
30 | * | |
31 | * Or submit a bug report through the following website: | |
32 | * http://www.sf.net/projects/lksctp | |
33 | * | |
34 | * Written or modified by: | |
35 | * La Monte H.P. Yarroll <piggy@acm.org> | |
36 | * Karl Knutson <karl@athena.chicago.il.us> | |
37 | * Jon Grimm <jgrimm@austin.ibm.com> | |
38 | * Sridhar Samudrala <sri@us.ibm.com> | |
39 | * | |
40 | * Any bugs reported given to us we will try to fix... any fixes shared will | |
41 | * be incorporated into the next SCTP release. | |
42 | */ | |
43 | ||
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> | |
8d2f9e81 | 52 | #include <net/ip.h> |
1da177e4 | 53 | #include <net/icmp.h> |
7c73a6fa | 54 | #include <net/net_namespace.h> |
1da177e4 | 55 | |
1da177e4 LT |
56 | #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> | |
9ad0977f | 61 | #include <net/sctp/checksum.h> |
1da177e4 LT |
62 | |
63 | /* Forward declarations for private helpers. */ | |
e83963b7 | 64 | static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet, |
1da177e4 | 65 | struct sctp_chunk *chunk); |
e83963b7 VY |
66 | static void sctp_packet_append_data(struct sctp_packet *packet, |
67 | struct sctp_chunk *chunk); | |
68 | static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet, | |
69 | struct sctp_chunk *chunk, | |
70 | u16 chunk_len); | |
1da177e4 LT |
71 | |
72 | /* Config a packet. | |
73 | * This appears to be a followup set of initializations. | |
74 | */ | |
75 | struct sctp_packet *sctp_packet_config(struct sctp_packet *packet, | |
76 | __u32 vtag, int ecn_capable) | |
77 | { | |
78 | struct sctp_chunk *chunk = NULL; | |
79 | ||
0dc47877 | 80 | SCTP_DEBUG_PRINTK("%s: packet:%p vtag:0x%x\n", __func__, |
1da177e4 LT |
81 | packet, vtag); |
82 | ||
83 | packet->vtag = vtag; | |
84 | packet->has_cookie_echo = 0; | |
85 | packet->has_sack = 0; | |
a29a5bd4 | 86 | packet->has_auth = 0; |
4cd57c80 | 87 | packet->has_data = 0; |
1da177e4 | 88 | packet->ipfragok = 0; |
a29a5bd4 | 89 | packet->auth = NULL; |
1da177e4 LT |
90 | |
91 | if (ecn_capable && sctp_packet_empty(packet)) { | |
92 | chunk = sctp_get_ecne_prepend(packet->transport->asoc); | |
93 | ||
94 | /* If there a is a prepend chunk stick it on the list before | |
d808ad9a YH |
95 | * any other chunks get appended. |
96 | */ | |
1da177e4 LT |
97 | if (chunk) |
98 | sctp_packet_append_chunk(packet, chunk); | |
99 | } | |
100 | ||
101 | return packet; | |
102 | } | |
103 | ||
104 | /* Initialize the packet structure. */ | |
105 | struct sctp_packet *sctp_packet_init(struct sctp_packet *packet, | |
106 | struct sctp_transport *transport, | |
107 | __u16 sport, __u16 dport) | |
108 | { | |
109 | struct sctp_association *asoc = transport->asoc; | |
110 | size_t overhead; | |
111 | ||
0dc47877 | 112 | SCTP_DEBUG_PRINTK("%s: packet:%p transport:%p\n", __func__, |
1da177e4 LT |
113 | packet, transport); |
114 | ||
115 | packet->transport = transport; | |
116 | packet->source_port = sport; | |
117 | packet->destination_port = dport; | |
79af02c2 | 118 | INIT_LIST_HEAD(&packet->chunk_list); |
1da177e4 | 119 | if (asoc) { |
d808ad9a YH |
120 | struct sctp_sock *sp = sctp_sk(asoc->base.sk); |
121 | overhead = sp->pf->af->net_header_len; | |
1da177e4 LT |
122 | } else { |
123 | overhead = sizeof(struct ipv6hdr); | |
124 | } | |
125 | overhead += sizeof(struct sctphdr); | |
126 | packet->overhead = overhead; | |
127 | packet->size = overhead; | |
128 | packet->vtag = 0; | |
129 | packet->has_cookie_echo = 0; | |
130 | packet->has_sack = 0; | |
a29a5bd4 | 131 | packet->has_auth = 0; |
4cd57c80 | 132 | packet->has_data = 0; |
1da177e4 LT |
133 | packet->ipfragok = 0; |
134 | packet->malloced = 0; | |
a29a5bd4 | 135 | packet->auth = NULL; |
1da177e4 LT |
136 | return packet; |
137 | } | |
138 | ||
139 | /* Free a packet. */ | |
140 | void sctp_packet_free(struct sctp_packet *packet) | |
141 | { | |
79af02c2 | 142 | struct sctp_chunk *chunk, *tmp; |
1da177e4 | 143 | |
0dc47877 | 144 | SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet); |
1da177e4 | 145 | |
79af02c2 DM |
146 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
147 | list_del_init(&chunk->list); | |
1da177e4 | 148 | sctp_chunk_free(chunk); |
79af02c2 | 149 | } |
1da177e4 LT |
150 | |
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 | */ | |
162 | sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *packet, | |
2e3216cd VY |
163 | struct sctp_chunk *chunk, |
164 | int one_packet) | |
1da177e4 LT |
165 | { |
166 | sctp_xmit_t retval; | |
167 | int error = 0; | |
168 | ||
0dc47877 | 169 | SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__, |
1da177e4 LT |
170 | 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 | */ | |
2e3216cd VY |
182 | if (!one_packet) |
183 | retval = sctp_packet_append_chunk(packet, | |
184 | chunk); | |
1da177e4 LT |
185 | } |
186 | break; | |
187 | ||
188 | case SCTP_XMIT_RWND_FULL: | |
189 | case SCTP_XMIT_OK: | |
190 | case SCTP_XMIT_NAGLE_DELAY: | |
191 | break; | |
3ff50b79 | 192 | } |
1da177e4 LT |
193 | |
194 | return retval; | |
195 | } | |
196 | ||
4cd57c80 VY |
197 | /* Try to bundle an auth chunk into the packet. */ |
198 | static 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 | */ | |
212 | if (chunk->chunk_hdr->type == SCTP_CID_AUTH || pkt->auth) | |
213 | 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 | ||
1da177e4 LT |
230 | /* Try to bundle a SACK with the packet. */ |
231 | static 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; | |
af87b823 | 242 | struct timer_list *timer; |
1da177e4 | 243 | asoc = pkt->transport->asoc; |
af87b823 | 244 | timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK]; |
1da177e4 | 245 | |
af87b823 DG |
246 | /* If the SACK timer is running, we have a pending SACK */ |
247 | if (timer_pending(timer)) { | |
1da177e4 LT |
248 | struct sctp_chunk *sack; |
249 | asoc->a_rwnd = asoc->rwnd; | |
250 | sack = sctp_make_sack(asoc); | |
251 | if (sack) { | |
1da177e4 LT |
252 | retval = sctp_packet_append_chunk(pkt, sack); |
253 | asoc->peer.sack_needed = 0; | |
af87b823 | 254 | if (del_timer(timer)) |
1da177e4 LT |
255 | 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 | */ | |
265 | sctp_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)); | |
1da177e4 | 270 | |
0dc47877 | 271 | SCTP_DEBUG_PRINTK("%s: packet:%p chunk:%p\n", __func__, packet, |
1da177e4 LT |
272 | chunk); |
273 | ||
e83963b7 VY |
274 | /* 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 | ||
4cd57c80 VY |
284 | /* Try to bundle AUTH chunk */ |
285 | retval = sctp_packet_bundle_auth(packet, chunk); | |
286 | if (retval != SCTP_XMIT_OK) | |
287 | goto finish; | |
1da177e4 | 288 | |
4cd57c80 VY |
289 | /* Try to bundle SACK chunk */ |
290 | retval = sctp_packet_bundle_sack(packet, chunk); | |
1da177e4 LT |
291 | if (retval != SCTP_XMIT_OK) |
292 | goto finish; | |
293 | ||
e83963b7 VY |
294 | /* 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; | |
1da177e4 | 298 | |
e83963b7 | 299 | /* We believe that this chunk is OK to add to the packet */ |
4cd57c80 VY |
300 | switch (chunk->chunk_hdr->type) { |
301 | case SCTP_CID_DATA: | |
e83963b7 VY |
302 | /* Account for the data being in the packet */ |
303 | sctp_packet_append_data(packet, chunk); | |
1da177e4 LT |
304 | /* Disallow SACK bundling after DATA. */ |
305 | packet->has_sack = 1; | |
4cd57c80 VY |
306 | /* 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; | |
759af00e VY |
310 | /* timestamp the chunk for rtx purposes */ |
311 | chunk->sent_at = jiffies; | |
4cd57c80 VY |
312 | break; |
313 | case SCTP_CID_COOKIE_ECHO: | |
1da177e4 | 314 | packet->has_cookie_echo = 1; |
4cd57c80 VY |
315 | break; |
316 | ||
317 | case SCTP_CID_SACK: | |
1da177e4 | 318 | packet->has_sack = 1; |
4cd57c80 VY |
319 | break; |
320 | ||
321 | case SCTP_CID_AUTH: | |
322 | packet->has_auth = 1; | |
323 | packet->auth = chunk; | |
324 | break; | |
325 | } | |
1da177e4 LT |
326 | |
327 | /* It is OK to send this chunk. */ | |
79af02c2 | 328 | list_add_tail(&chunk->list, &packet->chunk_list); |
1da177e4 LT |
329 | packet->size += chunk_len; |
330 | chunk->transport = packet->transport; | |
331 | finish: | |
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 | */ | |
340 | int 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; | |
1da177e4 | 345 | struct sk_buff *nskb; |
79af02c2 | 346 | struct sctp_chunk *chunk, *tmp; |
1da177e4 LT |
347 | struct sock *sk; |
348 | int err = 0; | |
349 | int padding; /* How much padding do we need? */ | |
350 | __u8 has_data = 0; | |
503b55fd | 351 | struct dst_entry *dst = tp->dst; |
4cd57c80 VY |
352 | unsigned char *auth = NULL; /* pointer to auth in skb data */ |
353 | __u32 cksum_buf_len = sizeof(struct sctphdr); | |
1da177e4 | 354 | |
0dc47877 | 355 | SCTP_DEBUG_PRINTK("%s: packet:%p\n", __func__, packet); |
1da177e4 LT |
356 | |
357 | /* Do NOT generate a chunkless packet. */ | |
79af02c2 | 358 | if (list_empty(&packet->chunk_list)) |
1da177e4 LT |
359 | return err; |
360 | ||
361 | /* Set up convenience variables... */ | |
79af02c2 | 362 | chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list); |
1da177e4 LT |
363 | sk = chunk->skb->sk; |
364 | ||
365 | /* Allocate the new skb. */ | |
594ccc14 | 366 | nskb = alloc_skb(packet->size + LL_MAX_HEADER, GFP_ATOMIC); |
1da177e4 LT |
367 | if (!nskb) |
368 | goto nomem; | |
369 | ||
370 | /* Make sure the outbound skb has enough header room reserved. */ | |
594ccc14 | 371 | skb_reserve(nskb, packet->overhead + LL_MAX_HEADER); |
1da177e4 LT |
372 | |
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 | ||
503b55fd SS |
378 | /* 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 | } | |
adf30907 ED |
386 | dst = dst_clone(tp->dst); |
387 | skb_dst_set(nskb, dst); | |
ff0ac74a | 388 | if (!dst) |
503b55fd | 389 | goto no_route; |
503b55fd | 390 | |
1da177e4 LT |
391 | /* Build the SCTP header. */ |
392 | sh = (struct sctphdr *)skb_push(nskb, sizeof(struct sctphdr)); | |
8dc92f7e | 393 | skb_reset_transport_header(nskb); |
1da177e4 LT |
394 | 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 | ||
1da177e4 LT |
408 | /** |
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"); | |
79af02c2 DM |
428 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
429 | list_del_init(&chunk->list); | |
1da177e4 LT |
430 | if (sctp_chunk_is_data(chunk)) { |
431 | ||
432 | if (!chunk->has_tsn) { | |
433 | sctp_chunk_assign_ssn(chunk); | |
434 | sctp_chunk_assign_tsn(chunk); | |
435 | ||
436 | /* 6.3.1 C4) When data is in flight and when allowed | |
437 | * by rule C5, a new RTT measurement MUST be made each | |
438 | * round trip. Furthermore, new RTT measurements | |
439 | * SHOULD be made no more than once per round-trip | |
440 | * for a given destination transport address. | |
441 | */ | |
442 | ||
443 | if (!tp->rto_pending) { | |
444 | chunk->rtt_in_progress = 1; | |
445 | tp->rto_pending = 1; | |
446 | } | |
447 | } else | |
448 | chunk->resent = 1; | |
449 | ||
1da177e4 LT |
450 | has_data = 1; |
451 | } | |
452 | ||
453 | padding = WORD_ROUND(chunk->skb->len) - chunk->skb->len; | |
454 | if (padding) | |
455 | memset(skb_put(chunk->skb, padding), 0, padding); | |
456 | ||
4cd57c80 VY |
457 | /* if this is the auth chunk that we are adding, |
458 | * store pointer where it will be added and put | |
459 | * the auth into the packet. | |
460 | */ | |
461 | if (chunk == packet->auth) | |
462 | auth = skb_tail_pointer(nskb); | |
463 | ||
464 | cksum_buf_len += chunk->skb->len; | |
465 | memcpy(skb_put(nskb, chunk->skb->len), | |
503b55fd | 466 | chunk->skb->data, chunk->skb->len); |
1da177e4 LT |
467 | |
468 | SCTP_DEBUG_PRINTK("%s %p[%s] %s 0x%x, %s %d, %s %d, %s %d\n", | |
469 | "*** Chunk", chunk, | |
470 | sctp_cname(SCTP_ST_CHUNK( | |
471 | chunk->chunk_hdr->type)), | |
472 | chunk->has_tsn ? "TSN" : "No TSN", | |
473 | chunk->has_tsn ? | |
474 | ntohl(chunk->subh.data_hdr->tsn) : 0, | |
475 | "length", ntohs(chunk->chunk_hdr->length), | |
476 | "chunk->skb->len", chunk->skb->len, | |
477 | "rtt_in_progress", chunk->rtt_in_progress); | |
478 | ||
479 | /* | |
480 | * If this is a control chunk, this is our last | |
481 | * reference. Free data chunks after they've been | |
482 | * acknowledged or have failed. | |
483 | */ | |
484 | if (!sctp_chunk_is_data(chunk)) | |
d808ad9a | 485 | sctp_chunk_free(chunk); |
1da177e4 LT |
486 | } |
487 | ||
4cd57c80 VY |
488 | /* SCTP-AUTH, Section 6.2 |
489 | * The sender MUST calculate the MAC as described in RFC2104 [2] | |
490 | * using the hash function H as described by the MAC Identifier and | |
491 | * the shared association key K based on the endpoint pair shared key | |
492 | * described by the shared key identifier. The 'data' used for the | |
493 | * computation of the AUTH-chunk is given by the AUTH chunk with its | |
494 | * HMAC field set to zero (as shown in Figure 6) followed by all | |
495 | * chunks that are placed after the AUTH chunk in the SCTP packet. | |
496 | */ | |
497 | if (auth) | |
498 | sctp_auth_calculate_hmac(asoc, nskb, | |
499 | (struct sctp_auth_chunk *)auth, | |
500 | GFP_ATOMIC); | |
501 | ||
502 | /* 2) Calculate the Adler-32 checksum of the whole packet, | |
503 | * including the SCTP common header and all the | |
504 | * chunks. | |
505 | * | |
506 | * Note: Adler-32 is no longer applicable, as has been replaced | |
507 | * by CRC32-C as described in <draft-ietf-tsvwg-sctpcsum-02.txt>. | |
508 | */ | |
8dc92f7e JB |
509 | if (!sctp_checksum_disable && |
510 | !(dst->dev->features & (NETIF_F_NO_CSUM | NETIF_F_SCTP_CSUM))) { | |
4458f04c VY |
511 | __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len); |
512 | ||
513 | /* 3) Put the resultant value into the checksum field in the | |
514 | * common header, and leave the rest of the bits unchanged. | |
515 | */ | |
516 | sh->checksum = sctp_end_cksum(crc32); | |
8dc92f7e JB |
517 | } else { |
518 | if (dst->dev->features & NETIF_F_SCTP_CSUM) { | |
519 | /* no need to seed psuedo checksum for SCTP */ | |
520 | nskb->ip_summed = CHECKSUM_PARTIAL; | |
521 | nskb->csum_start = (skb_transport_header(nskb) - | |
522 | nskb->head); | |
523 | nskb->csum_offset = offsetof(struct sctphdr, checksum); | |
524 | } else { | |
525 | nskb->ip_summed = CHECKSUM_UNNECESSARY; | |
526 | } | |
527 | } | |
1da177e4 | 528 | |
1da177e4 LT |
529 | /* IP layer ECN support |
530 | * From RFC 2481 | |
531 | * "The ECN-Capable Transport (ECT) bit would be set by the | |
532 | * data sender to indicate that the end-points of the | |
533 | * transport protocol are ECN-capable." | |
534 | * | |
535 | * Now setting the ECT bit all the time, as it should not cause | |
536 | * any problems protocol-wise even if our peer ignores it. | |
537 | * | |
538 | * Note: The works for IPv6 layer checks this bit too later | |
539 | * in transmission. See IP6_ECN_flow_xmit(). | |
540 | */ | |
b9031d9d | 541 | (*tp->af_specific->ecn_capable)(nskb->sk); |
1da177e4 LT |
542 | |
543 | /* Set up the IP options. */ | |
544 | /* BUG: not implemented | |
545 | * For v4 this all lives somewhere in sk->sk_opt... | |
546 | */ | |
547 | ||
548 | /* Dump that on IP! */ | |
549 | if (asoc && asoc->peer.last_sent_to != tp) { | |
550 | /* Considering the multiple CPU scenario, this is a | |
551 | * "correcter" place for last_sent_to. --xguo | |
552 | */ | |
553 | asoc->peer.last_sent_to = tp; | |
554 | } | |
555 | ||
556 | if (has_data) { | |
557 | struct timer_list *timer; | |
558 | unsigned long timeout; | |
559 | ||
560 | tp->last_time_used = jiffies; | |
561 | ||
562 | /* Restart the AUTOCLOSE timer when sending data. */ | |
563 | if (sctp_state(asoc, ESTABLISHED) && asoc->autoclose) { | |
564 | timer = &asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]; | |
565 | timeout = asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]; | |
566 | ||
567 | if (!mod_timer(timer, jiffies + timeout)) | |
568 | sctp_association_hold(asoc); | |
569 | } | |
570 | } | |
571 | ||
1da177e4 LT |
572 | SCTP_DEBUG_PRINTK("***sctp_transmit_packet*** skb len %d\n", |
573 | nskb->len); | |
574 | ||
f880374c HX |
575 | nskb->local_df = packet->ipfragok; |
576 | (*tp->af_specific->sctp_xmit)(nskb, tp); | |
1da177e4 LT |
577 | |
578 | out: | |
579 | packet->size = packet->overhead; | |
580 | return err; | |
581 | no_route: | |
582 | kfree_skb(nskb); | |
7c73a6fa | 583 | IP_INC_STATS_BH(&init_net, IPSTATS_MIB_OUTNOROUTES); |
1da177e4 LT |
584 | |
585 | /* FIXME: Returning the 'err' will effect all the associations | |
586 | * associated with a socket, although only one of the paths of the | |
587 | * association is unreachable. | |
588 | * The real failure of a transport or association can be passed on | |
589 | * to the user via notifications. So setting this error may not be | |
590 | * required. | |
591 | */ | |
592 | /* err = -EHOSTUNREACH; */ | |
593 | err: | |
594 | /* Control chunks are unreliable so just drop them. DATA chunks | |
595 | * will get resent or dropped later. | |
596 | */ | |
597 | ||
79af02c2 DM |
598 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
599 | list_del_init(&chunk->list); | |
1da177e4 | 600 | if (!sctp_chunk_is_data(chunk)) |
d808ad9a | 601 | sctp_chunk_free(chunk); |
1da177e4 LT |
602 | } |
603 | goto out; | |
604 | nomem: | |
605 | err = -ENOMEM; | |
606 | goto err; | |
607 | } | |
608 | ||
609 | /******************************************************************** | |
610 | * 2nd Level Abstractions | |
611 | ********************************************************************/ | |
612 | ||
e83963b7 VY |
613 | /* This private function check to see if a chunk can be added */ |
614 | static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet, | |
1da177e4 LT |
615 | struct sctp_chunk *chunk) |
616 | { | |
617 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
e83963b7 | 618 | size_t datasize, rwnd, inflight, flight_size; |
1da177e4 LT |
619 | struct sctp_transport *transport = packet->transport; |
620 | __u32 max_burst_bytes; | |
621 | struct sctp_association *asoc = transport->asoc; | |
1da177e4 LT |
622 | struct sctp_outq *q = &asoc->outqueue; |
623 | ||
624 | /* RFC 2960 6.1 Transmission of DATA Chunks | |
625 | * | |
626 | * A) At any given time, the data sender MUST NOT transmit new data to | |
627 | * any destination transport address if its peer's rwnd indicates | |
628 | * that the peer has no buffer space (i.e. rwnd is 0, see Section | |
629 | * 6.2.1). However, regardless of the value of rwnd (including if it | |
630 | * is 0), the data sender can always have one DATA chunk in flight to | |
631 | * the receiver if allowed by cwnd (see rule B below). This rule | |
632 | * allows the sender to probe for a change in rwnd that the sender | |
633 | * missed due to the SACK having been lost in transit from the data | |
634 | * receiver to the data sender. | |
635 | */ | |
636 | ||
637 | rwnd = asoc->peer.rwnd; | |
e83963b7 VY |
638 | inflight = q->outstanding_bytes; |
639 | flight_size = transport->flight_size; | |
1da177e4 LT |
640 | |
641 | datasize = sctp_data_size(chunk); | |
642 | ||
643 | if (datasize > rwnd) { | |
644 | if (inflight > 0) { | |
645 | /* We have (at least) one data chunk in flight, | |
646 | * so we can't fall back to rule 6.1 B). | |
647 | */ | |
648 | retval = SCTP_XMIT_RWND_FULL; | |
649 | goto finish; | |
650 | } | |
651 | } | |
652 | ||
653 | /* sctpimpguide-05 2.14.2 | |
654 | * D) When the time comes for the sender to | |
655 | * transmit new DATA chunks, the protocol parameter Max.Burst MUST | |
656 | * first be applied to limit how many new DATA chunks may be sent. | |
657 | * The limit is applied by adjusting cwnd as follows: | |
658 | * if ((flightsize + Max.Burst * MTU) < cwnd) | |
659 | * cwnd = flightsize + Max.Burst * MTU | |
660 | */ | |
52ccb8e9 | 661 | max_burst_bytes = asoc->max_burst * asoc->pathmtu; |
e83963b7 VY |
662 | if ((flight_size + max_burst_bytes) < transport->cwnd) { |
663 | transport->cwnd = flight_size + max_burst_bytes; | |
1da177e4 LT |
664 | SCTP_DEBUG_PRINTK("%s: cwnd limited by max_burst: " |
665 | "transport: %p, cwnd: %d, " | |
666 | "ssthresh: %d, flight_size: %d, " | |
667 | "pba: %d\n", | |
0dc47877 | 668 | __func__, transport, |
1da177e4 LT |
669 | transport->cwnd, |
670 | transport->ssthresh, | |
671 | transport->flight_size, | |
672 | transport->partial_bytes_acked); | |
673 | } | |
674 | ||
675 | /* RFC 2960 6.1 Transmission of DATA Chunks | |
676 | * | |
677 | * B) At any given time, the sender MUST NOT transmit new data | |
678 | * to a given transport address if it has cwnd or more bytes | |
679 | * of data outstanding to that transport address. | |
680 | */ | |
681 | /* RFC 7.2.4 & the Implementers Guide 2.8. | |
682 | * | |
683 | * 3) ... | |
684 | * When a Fast Retransmit is being performed the sender SHOULD | |
685 | * ignore the value of cwnd and SHOULD NOT delay retransmission. | |
686 | */ | |
c226ef9b | 687 | if (chunk->fast_retransmit != SCTP_NEED_FRTX) |
e83963b7 | 688 | if (flight_size >= transport->cwnd) { |
1da177e4 LT |
689 | retval = SCTP_XMIT_RWND_FULL; |
690 | goto finish; | |
691 | } | |
692 | ||
693 | /* Nagle's algorithm to solve small-packet problem: | |
694 | * Inhibit the sending of new chunks when new outgoing data arrives | |
695 | * if any previously transmitted data on the connection remains | |
696 | * unacknowledged. | |
697 | */ | |
e83963b7 VY |
698 | if (!sctp_sk(asoc->base.sk)->nodelay && sctp_packet_empty(packet) && |
699 | inflight && sctp_state(asoc, ESTABLISHED)) { | |
b29e7907 VY |
700 | unsigned max = transport->pathmtu - packet->overhead; |
701 | unsigned len = chunk->skb->len + q->out_qlen; | |
1da177e4 LT |
702 | |
703 | /* Check whether this chunk and all the rest of pending | |
704 | * data will fit or delay in hopes of bundling a full | |
705 | * sized packet. | |
706 | */ | |
b29e7907 | 707 | if (len < max) { |
1da177e4 LT |
708 | retval = SCTP_XMIT_NAGLE_DELAY; |
709 | goto finish; | |
710 | } | |
711 | } | |
712 | ||
e83963b7 VY |
713 | finish: |
714 | return retval; | |
715 | } | |
716 | ||
717 | /* This private function does management things when adding DATA chunk */ | |
718 | static void sctp_packet_append_data(struct sctp_packet *packet, | |
719 | struct sctp_chunk *chunk) | |
720 | { | |
721 | struct sctp_transport *transport = packet->transport; | |
722 | size_t datasize = sctp_data_size(chunk); | |
723 | struct sctp_association *asoc = transport->asoc; | |
724 | u32 rwnd = asoc->peer.rwnd; | |
725 | ||
1da177e4 LT |
726 | /* Keep track of how many bytes are in flight over this transport. */ |
727 | transport->flight_size += datasize; | |
728 | ||
729 | /* Keep track of how many bytes are in flight to the receiver. */ | |
730 | asoc->outqueue.outstanding_bytes += datasize; | |
731 | ||
cd497885 SS |
732 | /* Update our view of the receiver's rwnd. Include sk_buff overhead |
733 | * while updating peer.rwnd so that it reduces the chances of a | |
734 | * receiver running out of receive buffer space even when receive | |
735 | * window is still open. This can happen when a sender is sending | |
736 | * sending small messages. | |
737 | */ | |
738 | datasize += sizeof(struct sk_buff); | |
1da177e4 LT |
739 | if (datasize < rwnd) |
740 | rwnd -= datasize; | |
741 | else | |
742 | rwnd = 0; | |
743 | ||
744 | asoc->peer.rwnd = rwnd; | |
745 | /* Has been accepted for transmission. */ | |
746 | if (!asoc->peer.prsctp_capable) | |
747 | chunk->msg->can_abandon = 0; | |
e83963b7 VY |
748 | } |
749 | ||
750 | static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet, | |
751 | struct sctp_chunk *chunk, | |
752 | u16 chunk_len) | |
753 | { | |
754 | size_t psize; | |
755 | size_t pmtu; | |
756 | int too_big; | |
757 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
758 | ||
759 | psize = packet->size; | |
760 | pmtu = ((packet->transport->asoc) ? | |
761 | (packet->transport->asoc->pathmtu) : | |
762 | (packet->transport->pathmtu)); | |
763 | ||
764 | too_big = (psize + chunk_len > pmtu); | |
765 | ||
766 | /* Decide if we need to fragment or resubmit later. */ | |
767 | if (too_big) { | |
768 | /* It's OK to fragmet at IP level if any one of the following | |
769 | * is true: | |
770 | * 1. The packet is empty (meaning this chunk is greater | |
771 | * the MTU) | |
772 | * 2. The chunk we are adding is a control chunk | |
773 | * 3. The packet doesn't have any data in it yet and data | |
774 | * requires authentication. | |
775 | */ | |
776 | if (sctp_packet_empty(packet) || !sctp_chunk_is_data(chunk) || | |
777 | (!packet->has_data && chunk->auth)) { | |
778 | /* We no longer do re-fragmentation. | |
779 | * Just fragment at the IP layer, if we | |
780 | * actually hit this condition | |
781 | */ | |
782 | packet->ipfragok = 1; | |
783 | } else { | |
784 | retval = SCTP_XMIT_PMTU_FULL; | |
785 | } | |
786 | } | |
1da177e4 | 787 | |
1da177e4 LT |
788 | return retval; |
789 | } |