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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 | |
4b2f13a2 JK |
23 | * along with GNU CC; see the file COPYING. If not, see |
24 | * <http://www.gnu.org/licenses/>. | |
1da177e4 LT |
25 | * |
26 | * Please send any bug reports or fixes you make to the | |
27 | * email address(es): | |
91705c61 | 28 | * lksctp developers <linux-sctp@vger.kernel.org> |
1da177e4 | 29 | * |
1da177e4 LT |
30 | * Written or modified by: |
31 | * La Monte H.P. Yarroll <piggy@acm.org> | |
32 | * Karl Knutson <karl@athena.chicago.il.us> | |
33 | * Jon Grimm <jgrimm@austin.ibm.com> | |
34 | * Sridhar Samudrala <sri@us.ibm.com> | |
1da177e4 LT |
35 | */ |
36 | ||
145ce502 JP |
37 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
38 | ||
1da177e4 LT |
39 | #include <linux/types.h> |
40 | #include <linux/kernel.h> | |
41 | #include <linux/wait.h> | |
42 | #include <linux/time.h> | |
43 | #include <linux/ip.h> | |
44 | #include <linux/ipv6.h> | |
45 | #include <linux/init.h> | |
5a0e3ad6 | 46 | #include <linux/slab.h> |
1da177e4 | 47 | #include <net/inet_ecn.h> |
8d2f9e81 | 48 | #include <net/ip.h> |
1da177e4 | 49 | #include <net/icmp.h> |
7c73a6fa | 50 | #include <net/net_namespace.h> |
1da177e4 | 51 | |
1da177e4 LT |
52 | #include <linux/socket.h> /* for sa_family_t */ |
53 | #include <net/sock.h> | |
54 | ||
55 | #include <net/sctp/sctp.h> | |
56 | #include <net/sctp/sm.h> | |
9ad0977f | 57 | #include <net/sctp/checksum.h> |
1da177e4 LT |
58 | |
59 | /* Forward declarations for private helpers. */ | |
ed106277 NH |
60 | static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet, |
61 | struct sctp_chunk *chunk); | |
e83963b7 | 62 | static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet, |
1da177e4 | 63 | struct sctp_chunk *chunk); |
e83963b7 VY |
64 | static void sctp_packet_append_data(struct sctp_packet *packet, |
65 | struct sctp_chunk *chunk); | |
66 | static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet, | |
67 | struct sctp_chunk *chunk, | |
68 | u16 chunk_len); | |
1da177e4 | 69 | |
be297143 WY |
70 | static void sctp_packet_reset(struct sctp_packet *packet) |
71 | { | |
72 | packet->size = packet->overhead; | |
73 | packet->has_cookie_echo = 0; | |
74 | packet->has_sack = 0; | |
75 | packet->has_data = 0; | |
76 | packet->has_auth = 0; | |
77 | packet->ipfragok = 0; | |
78 | packet->auth = NULL; | |
79 | } | |
80 | ||
1da177e4 LT |
81 | /* Config a packet. |
82 | * This appears to be a followup set of initializations. | |
83 | */ | |
66b91d2c MRL |
84 | void sctp_packet_config(struct sctp_packet *packet, __u32 vtag, |
85 | int ecn_capable) | |
1da177e4 | 86 | { |
90017acc MRL |
87 | struct sctp_transport *tp = packet->transport; |
88 | struct sctp_association *asoc = tp->asoc; | |
1da177e4 | 89 | |
bb33381d | 90 | pr_debug("%s: packet:%p vtag:0x%x\n", __func__, packet, vtag); |
1da177e4 LT |
91 | |
92 | packet->vtag = vtag; | |
1da177e4 | 93 | |
90017acc MRL |
94 | if (asoc && tp->dst) { |
95 | struct sock *sk = asoc->base.sk; | |
96 | ||
97 | rcu_read_lock(); | |
98 | if (__sk_dst_get(sk) != tp->dst) { | |
99 | dst_hold(tp->dst); | |
100 | sk_setup_caps(sk, tp->dst); | |
101 | } | |
102 | ||
103 | if (sk_can_gso(sk)) { | |
104 | struct net_device *dev = tp->dst->dev; | |
105 | ||
106 | packet->max_size = dev->gso_max_size; | |
107 | } else { | |
108 | packet->max_size = asoc->pathmtu; | |
109 | } | |
110 | rcu_read_unlock(); | |
111 | ||
112 | } else { | |
113 | packet->max_size = tp->pathmtu; | |
114 | } | |
115 | ||
1da177e4 | 116 | if (ecn_capable && sctp_packet_empty(packet)) { |
90017acc | 117 | struct sctp_chunk *chunk; |
1da177e4 LT |
118 | |
119 | /* If there a is a prepend chunk stick it on the list before | |
d808ad9a YH |
120 | * any other chunks get appended. |
121 | */ | |
90017acc | 122 | chunk = sctp_get_ecne_prepend(asoc); |
1da177e4 LT |
123 | if (chunk) |
124 | sctp_packet_append_chunk(packet, chunk); | |
125 | } | |
1da177e4 LT |
126 | } |
127 | ||
128 | /* Initialize the packet structure. */ | |
66b91d2c MRL |
129 | void sctp_packet_init(struct sctp_packet *packet, |
130 | struct sctp_transport *transport, | |
131 | __u16 sport, __u16 dport) | |
1da177e4 LT |
132 | { |
133 | struct sctp_association *asoc = transport->asoc; | |
134 | size_t overhead; | |
135 | ||
bb33381d | 136 | pr_debug("%s: packet:%p transport:%p\n", __func__, packet, transport); |
1da177e4 LT |
137 | |
138 | packet->transport = transport; | |
139 | packet->source_port = sport; | |
140 | packet->destination_port = dport; | |
79af02c2 | 141 | INIT_LIST_HEAD(&packet->chunk_list); |
1da177e4 | 142 | if (asoc) { |
d808ad9a YH |
143 | struct sctp_sock *sp = sctp_sk(asoc->base.sk); |
144 | overhead = sp->pf->af->net_header_len; | |
1da177e4 LT |
145 | } else { |
146 | overhead = sizeof(struct ipv6hdr); | |
147 | } | |
148 | overhead += sizeof(struct sctphdr); | |
149 | packet->overhead = overhead; | |
be297143 | 150 | sctp_packet_reset(packet); |
1da177e4 | 151 | packet->vtag = 0; |
1da177e4 LT |
152 | } |
153 | ||
154 | /* Free a packet. */ | |
155 | void sctp_packet_free(struct sctp_packet *packet) | |
156 | { | |
79af02c2 | 157 | struct sctp_chunk *chunk, *tmp; |
1da177e4 | 158 | |
bb33381d | 159 | pr_debug("%s: packet:%p\n", __func__, packet); |
1da177e4 | 160 | |
79af02c2 DM |
161 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
162 | list_del_init(&chunk->list); | |
1da177e4 | 163 | sctp_chunk_free(chunk); |
79af02c2 | 164 | } |
1da177e4 LT |
165 | } |
166 | ||
167 | /* This routine tries to append the chunk to the offered packet. If adding | |
168 | * the chunk causes the packet to exceed the path MTU and COOKIE_ECHO chunk | |
169 | * is not present in the packet, it transmits the input packet. | |
170 | * Data can be bundled with a packet containing a COOKIE_ECHO chunk as long | |
171 | * as it can fit in the packet, but any more data that does not fit in this | |
172 | * packet can be sent only after receiving the COOKIE_ACK. | |
173 | */ | |
174 | sctp_xmit_t sctp_packet_transmit_chunk(struct sctp_packet *packet, | |
2e3216cd | 175 | struct sctp_chunk *chunk, |
cea8768f | 176 | int one_packet, gfp_t gfp) |
1da177e4 LT |
177 | { |
178 | sctp_xmit_t retval; | |
1da177e4 | 179 | |
3b55a537 | 180 | pr_debug("%s: packet:%p size:%Zu chunk:%p size:%d\n", __func__, |
942b3235 | 181 | packet, packet->size, chunk, chunk->skb ? chunk->skb->len : -1); |
1da177e4 LT |
182 | |
183 | switch ((retval = (sctp_packet_append_chunk(packet, chunk)))) { | |
184 | case SCTP_XMIT_PMTU_FULL: | |
185 | if (!packet->has_cookie_echo) { | |
64519440 XL |
186 | int error = 0; |
187 | ||
cea8768f | 188 | error = sctp_packet_transmit(packet, gfp); |
1da177e4 LT |
189 | if (error < 0) |
190 | chunk->skb->sk->sk_err = -error; | |
191 | ||
192 | /* If we have an empty packet, then we can NOT ever | |
193 | * return PMTU_FULL. | |
194 | */ | |
2e3216cd VY |
195 | if (!one_packet) |
196 | retval = sctp_packet_append_chunk(packet, | |
197 | chunk); | |
1da177e4 LT |
198 | } |
199 | break; | |
200 | ||
201 | case SCTP_XMIT_RWND_FULL: | |
202 | case SCTP_XMIT_OK: | |
526cbef7 | 203 | case SCTP_XMIT_DELAY: |
1da177e4 | 204 | break; |
3ff50b79 | 205 | } |
1da177e4 LT |
206 | |
207 | return retval; | |
208 | } | |
209 | ||
4cd57c80 VY |
210 | /* Try to bundle an auth chunk into the packet. */ |
211 | static sctp_xmit_t sctp_packet_bundle_auth(struct sctp_packet *pkt, | |
212 | struct sctp_chunk *chunk) | |
213 | { | |
214 | struct sctp_association *asoc = pkt->transport->asoc; | |
215 | struct sctp_chunk *auth; | |
216 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
217 | ||
218 | /* if we don't have an association, we can't do authentication */ | |
219 | if (!asoc) | |
220 | return retval; | |
221 | ||
222 | /* See if this is an auth chunk we are bundling or if | |
223 | * auth is already bundled. | |
224 | */ | |
4007cc88 | 225 | if (chunk->chunk_hdr->type == SCTP_CID_AUTH || pkt->has_auth) |
4cd57c80 VY |
226 | return retval; |
227 | ||
228 | /* if the peer did not request this chunk to be authenticated, | |
229 | * don't do it | |
230 | */ | |
231 | if (!chunk->auth) | |
232 | return retval; | |
233 | ||
234 | auth = sctp_make_auth(asoc); | |
235 | if (!auth) | |
236 | return retval; | |
237 | ||
ed106277 NH |
238 | retval = __sctp_packet_append_chunk(pkt, auth); |
239 | ||
240 | if (retval != SCTP_XMIT_OK) | |
241 | sctp_chunk_free(auth); | |
4cd57c80 VY |
242 | |
243 | return retval; | |
244 | } | |
245 | ||
1da177e4 LT |
246 | /* Try to bundle a SACK with the packet. */ |
247 | static sctp_xmit_t sctp_packet_bundle_sack(struct sctp_packet *pkt, | |
248 | struct sctp_chunk *chunk) | |
249 | { | |
250 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
251 | ||
252 | /* If sending DATA and haven't aleady bundled a SACK, try to | |
253 | * bundle one in to the packet. | |
254 | */ | |
255 | if (sctp_chunk_is_data(chunk) && !pkt->has_sack && | |
256 | !pkt->has_cookie_echo) { | |
257 | struct sctp_association *asoc; | |
af87b823 | 258 | struct timer_list *timer; |
1da177e4 | 259 | asoc = pkt->transport->asoc; |
af87b823 | 260 | timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK]; |
1da177e4 | 261 | |
af87b823 DG |
262 | /* If the SACK timer is running, we have a pending SACK */ |
263 | if (timer_pending(timer)) { | |
1da177e4 | 264 | struct sctp_chunk *sack; |
4244854d NH |
265 | |
266 | if (pkt->transport->sack_generation != | |
267 | pkt->transport->asoc->peer.sack_generation) | |
268 | return retval; | |
269 | ||
1da177e4 LT |
270 | asoc->a_rwnd = asoc->rwnd; |
271 | sack = sctp_make_sack(asoc); | |
272 | if (sack) { | |
ed106277 NH |
273 | retval = __sctp_packet_append_chunk(pkt, sack); |
274 | if (retval != SCTP_XMIT_OK) { | |
275 | sctp_chunk_free(sack); | |
276 | goto out; | |
277 | } | |
1da177e4 | 278 | asoc->peer.sack_needed = 0; |
af87b823 | 279 | if (del_timer(timer)) |
1da177e4 LT |
280 | sctp_association_put(asoc); |
281 | } | |
282 | } | |
283 | } | |
ed106277 | 284 | out: |
1da177e4 LT |
285 | return retval; |
286 | } | |
287 | ||
ed106277 | 288 | |
1da177e4 LT |
289 | /* Append a chunk to the offered packet reporting back any inability to do |
290 | * so. | |
291 | */ | |
ed106277 NH |
292 | static sctp_xmit_t __sctp_packet_append_chunk(struct sctp_packet *packet, |
293 | struct sctp_chunk *chunk) | |
1da177e4 LT |
294 | { |
295 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
e2f036a9 | 296 | __u16 chunk_len = SCTP_PAD4(ntohs(chunk->chunk_hdr->length)); |
1da177e4 | 297 | |
e83963b7 VY |
298 | /* Check to see if this chunk will fit into the packet */ |
299 | retval = sctp_packet_will_fit(packet, chunk, chunk_len); | |
300 | if (retval != SCTP_XMIT_OK) | |
301 | goto finish; | |
1da177e4 | 302 | |
e83963b7 | 303 | /* We believe that this chunk is OK to add to the packet */ |
4cd57c80 | 304 | switch (chunk->chunk_hdr->type) { |
f7010e61 | 305 | case SCTP_CID_DATA: |
e83963b7 VY |
306 | /* Account for the data being in the packet */ |
307 | sctp_packet_append_data(packet, chunk); | |
1da177e4 LT |
308 | /* Disallow SACK bundling after DATA. */ |
309 | packet->has_sack = 1; | |
4cd57c80 VY |
310 | /* Disallow AUTH bundling after DATA */ |
311 | packet->has_auth = 1; | |
312 | /* Let it be knows that packet has DATA in it */ | |
313 | packet->has_data = 1; | |
759af00e VY |
314 | /* timestamp the chunk for rtx purposes */ |
315 | chunk->sent_at = jiffies; | |
a6c2f792 XL |
316 | /* Mainly used for prsctp RTX policy */ |
317 | chunk->sent_count++; | |
4cd57c80 | 318 | break; |
f7010e61 | 319 | case SCTP_CID_COOKIE_ECHO: |
1da177e4 | 320 | packet->has_cookie_echo = 1; |
4cd57c80 VY |
321 | break; |
322 | ||
f7010e61 | 323 | case SCTP_CID_SACK: |
1da177e4 | 324 | packet->has_sack = 1; |
196d6759 MB |
325 | if (chunk->asoc) |
326 | chunk->asoc->stats.osacks++; | |
4cd57c80 VY |
327 | break; |
328 | ||
f7010e61 | 329 | case SCTP_CID_AUTH: |
4cd57c80 VY |
330 | packet->has_auth = 1; |
331 | packet->auth = chunk; | |
332 | break; | |
333 | } | |
1da177e4 LT |
334 | |
335 | /* It is OK to send this chunk. */ | |
79af02c2 | 336 | list_add_tail(&chunk->list, &packet->chunk_list); |
1da177e4 LT |
337 | packet->size += chunk_len; |
338 | chunk->transport = packet->transport; | |
339 | finish: | |
340 | return retval; | |
341 | } | |
342 | ||
ed106277 NH |
343 | /* Append a chunk to the offered packet reporting back any inability to do |
344 | * so. | |
345 | */ | |
346 | sctp_xmit_t sctp_packet_append_chunk(struct sctp_packet *packet, | |
347 | struct sctp_chunk *chunk) | |
348 | { | |
349 | sctp_xmit_t retval = SCTP_XMIT_OK; | |
350 | ||
bb33381d | 351 | pr_debug("%s: packet:%p chunk:%p\n", __func__, packet, chunk); |
ed106277 NH |
352 | |
353 | /* Data chunks are special. Before seeing what else we can | |
354 | * bundle into this packet, check to see if we are allowed to | |
355 | * send this DATA. | |
356 | */ | |
357 | if (sctp_chunk_is_data(chunk)) { | |
358 | retval = sctp_packet_can_append_data(packet, chunk); | |
359 | if (retval != SCTP_XMIT_OK) | |
360 | goto finish; | |
361 | } | |
362 | ||
363 | /* Try to bundle AUTH chunk */ | |
364 | retval = sctp_packet_bundle_auth(packet, chunk); | |
365 | if (retval != SCTP_XMIT_OK) | |
366 | goto finish; | |
367 | ||
368 | /* Try to bundle SACK chunk */ | |
369 | retval = sctp_packet_bundle_sack(packet, chunk); | |
370 | if (retval != SCTP_XMIT_OK) | |
371 | goto finish; | |
372 | ||
373 | retval = __sctp_packet_append_chunk(packet, chunk); | |
374 | ||
375 | finish: | |
376 | return retval; | |
377 | } | |
378 | ||
4c3a5bda TG |
379 | static void sctp_packet_release_owner(struct sk_buff *skb) |
380 | { | |
381 | sk_free(skb->sk); | |
382 | } | |
383 | ||
384 | static void sctp_packet_set_owner_w(struct sk_buff *skb, struct sock *sk) | |
385 | { | |
386 | skb_orphan(skb); | |
387 | skb->sk = sk; | |
388 | skb->destructor = sctp_packet_release_owner; | |
389 | ||
390 | /* | |
391 | * The data chunks have already been accounted for in sctp_sendmsg(), | |
392 | * therefore only reserve a single byte to keep socket around until | |
393 | * the packet has been transmitted. | |
394 | */ | |
395 | atomic_inc(&sk->sk_wmem_alloc); | |
396 | } | |
397 | ||
e4ff952a XL |
398 | static int sctp_packet_pack(struct sctp_packet *packet, |
399 | struct sk_buff *head, int gso, gfp_t gfp) | |
1da177e4 LT |
400 | { |
401 | struct sctp_transport *tp = packet->transport; | |
e4ff952a | 402 | struct sctp_auth_chunk *auth = NULL; |
79af02c2 | 403 | struct sctp_chunk *chunk, *tmp; |
e4ff952a XL |
404 | int pkt_count = 0, pkt_size; |
405 | struct sock *sk = head->sk; | |
406 | struct sk_buff *nskb; | |
ecc515d7 | 407 | int auth_len = 0; |
1da177e4 | 408 | |
90017acc | 409 | if (gso) { |
90017acc | 410 | skb_shinfo(head)->gso_type = sk->sk_gso_type; |
e4ff952a XL |
411 | NAPI_GRO_CB(head)->last = head; |
412 | } else { | |
413 | nskb = head; | |
414 | pkt_size = packet->size; | |
415 | goto merge; | |
90017acc | 416 | } |
1da177e4 | 417 | |
90017acc | 418 | do { |
e4ff952a XL |
419 | /* calculate the pkt_size and alloc nskb */ |
420 | pkt_size = packet->overhead; | |
421 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, | |
422 | list) { | |
423 | int padded = SCTP_PAD4(chunk->skb->len); | |
6eabca54 | 424 | |
e4ff952a XL |
425 | if (chunk == packet->auth) |
426 | auth_len = padded; | |
427 | else if (auth_len + padded + packet->overhead > | |
428 | tp->pathmtu) | |
429 | return 0; | |
430 | else if (pkt_size + padded > tp->pathmtu) | |
431 | break; | |
432 | pkt_size += padded; | |
90017acc | 433 | } |
e4ff952a XL |
434 | nskb = alloc_skb(pkt_size + MAX_HEADER, gfp); |
435 | if (!nskb) | |
436 | return 0; | |
437 | skb_reserve(nskb, packet->overhead + MAX_HEADER); | |
1da177e4 | 438 | |
e4ff952a XL |
439 | merge: |
440 | /* merge chunks into nskb and append nskb into head list */ | |
90017acc MRL |
441 | pkt_size -= packet->overhead; |
442 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { | |
e4ff952a XL |
443 | int padding; |
444 | ||
90017acc MRL |
445 | list_del_init(&chunk->list); |
446 | if (sctp_chunk_is_data(chunk)) { | |
cc6ac9bc XL |
447 | if (!sctp_chunk_retransmitted(chunk) && |
448 | !tp->rto_pending) { | |
90017acc MRL |
449 | chunk->rtt_in_progress = 1; |
450 | tp->rto_pending = 1; | |
451 | } | |
90017acc MRL |
452 | } |
453 | ||
e2f036a9 | 454 | padding = SCTP_PAD4(chunk->skb->len) - chunk->skb->len; |
90017acc MRL |
455 | if (padding) |
456 | memset(skb_put(chunk->skb, padding), 0, padding); | |
457 | ||
90017acc | 458 | if (chunk == packet->auth) |
e4ff952a XL |
459 | auth = (struct sctp_auth_chunk *) |
460 | skb_tail_pointer(nskb); | |
90017acc | 461 | |
e4ff952a XL |
462 | memcpy(skb_put(nskb, chunk->skb->len), chunk->skb->data, |
463 | chunk->skb->len); | |
1da177e4 | 464 | |
90017acc MRL |
465 | pr_debug("*** Chunk:%p[%s] %s 0x%x, length:%d, chunk->skb->len:%d, rtt_in_progress:%d\n", |
466 | chunk, | |
467 | sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)), | |
468 | chunk->has_tsn ? "TSN" : "No TSN", | |
469 | chunk->has_tsn ? ntohl(chunk->subh.data_hdr->tsn) : 0, | |
470 | ntohs(chunk->chunk_hdr->length), chunk->skb->len, | |
471 | chunk->rtt_in_progress); | |
472 | ||
e2f036a9 | 473 | pkt_size -= SCTP_PAD4(chunk->skb->len); |
1da177e4 | 474 | |
f1533cce | 475 | if (!sctp_chunk_is_data(chunk) && chunk != packet->auth) |
90017acc MRL |
476 | sctp_chunk_free(chunk); |
477 | ||
478 | if (!pkt_size) | |
479 | break; | |
480 | } | |
481 | ||
e4ff952a XL |
482 | if (auth) { |
483 | sctp_auth_calculate_hmac(tp->asoc, nskb, auth, gfp); | |
484 | /* free auth if no more chunks, or add it back */ | |
485 | if (list_empty(&packet->chunk_list)) | |
486 | sctp_chunk_free(packet->auth); | |
487 | else | |
1aa25ec2 XL |
488 | list_add(&packet->auth->list, |
489 | &packet->chunk_list); | |
f1533cce MRL |
490 | } |
491 | ||
e4ff952a XL |
492 | if (gso) { |
493 | if (skb_gro_receive(&head, nskb)) { | |
494 | kfree_skb(nskb); | |
495 | return 0; | |
496 | } | |
497 | if (WARN_ON_ONCE(skb_shinfo(head)->gso_segs >= | |
498 | sk->sk_gso_max_segs)) | |
499 | return 0; | |
41001faf | 500 | } |
e4ff952a XL |
501 | |
502 | pkt_count++; | |
90017acc | 503 | } while (!list_empty(&packet->chunk_list)); |
4cd57c80 | 504 | |
e4ff952a XL |
505 | if (gso) { |
506 | memset(head->cb, 0, max(sizeof(struct inet_skb_parm), | |
507 | sizeof(struct inet6_skb_parm))); | |
508 | skb_shinfo(head)->gso_segs = pkt_count; | |
509 | skb_shinfo(head)->gso_size = GSO_BY_FRAGS; | |
510 | rcu_read_lock(); | |
511 | if (skb_dst(head) != tp->dst) { | |
512 | dst_hold(tp->dst); | |
513 | sk_setup_caps(sk, tp->dst); | |
8dc92f7e | 514 | } |
e4ff952a XL |
515 | rcu_read_unlock(); |
516 | goto chksum; | |
8dc92f7e | 517 | } |
1da177e4 | 518 | |
e4ff952a XL |
519 | if (sctp_checksum_disable) |
520 | return 1; | |
1da177e4 | 521 | |
e4ff952a XL |
522 | if (!(skb_dst(head)->dev->features & NETIF_F_SCTP_CRC) || |
523 | dst_xfrm(skb_dst(head)) || packet->ipfragok) { | |
524 | struct sctphdr *sh = | |
525 | (struct sctphdr *)skb_transport_header(head); | |
1da177e4 | 526 | |
e4ff952a XL |
527 | sh->checksum = sctp_compute_cksum(head, 0); |
528 | } else { | |
529 | chksum: | |
530 | head->ip_summed = CHECKSUM_PARTIAL; | |
531 | head->csum_start = skb_transport_header(head) - head->head; | |
532 | head->csum_offset = offsetof(struct sctphdr, checksum); | |
1da177e4 LT |
533 | } |
534 | ||
e4ff952a XL |
535 | return pkt_count; |
536 | } | |
537 | ||
538 | /* All packets are sent to the network through this function from | |
539 | * sctp_outq_tail(). | |
540 | * | |
541 | * The return value is always 0 for now. | |
542 | */ | |
543 | int sctp_packet_transmit(struct sctp_packet *packet, gfp_t gfp) | |
544 | { | |
545 | struct sctp_transport *tp = packet->transport; | |
546 | struct sctp_association *asoc = tp->asoc; | |
547 | struct sctp_chunk *chunk, *tmp; | |
548 | int pkt_count, gso = 0; | |
c86a773c | 549 | int confirm; |
e4ff952a XL |
550 | struct dst_entry *dst; |
551 | struct sk_buff *head; | |
552 | struct sctphdr *sh; | |
553 | struct sock *sk; | |
1da177e4 | 554 | |
e4ff952a XL |
555 | pr_debug("%s: packet:%p\n", __func__, packet); |
556 | if (list_empty(&packet->chunk_list)) | |
557 | return 0; | |
558 | chunk = list_entry(packet->chunk_list.next, struct sctp_chunk, list); | |
559 | sk = chunk->skb->sk; | |
1da177e4 | 560 | |
e4ff952a XL |
561 | /* check gso */ |
562 | if (packet->size > tp->pathmtu && !packet->ipfragok) { | |
563 | if (!sk_can_gso(sk)) { | |
564 | pr_err_once("Trying to GSO but underlying device doesn't support it."); | |
565 | goto out; | |
1da177e4 | 566 | } |
e4ff952a XL |
567 | gso = 1; |
568 | } | |
569 | ||
570 | /* alloc head skb */ | |
571 | head = alloc_skb((gso ? packet->overhead : packet->size) + | |
572 | MAX_HEADER, gfp); | |
573 | if (!head) | |
574 | goto out; | |
575 | skb_reserve(head, packet->overhead + MAX_HEADER); | |
576 | sctp_packet_set_owner_w(head, sk); | |
577 | ||
578 | /* set sctp header */ | |
579 | sh = (struct sctphdr *)skb_push(head, sizeof(struct sctphdr)); | |
580 | skb_reset_transport_header(head); | |
581 | sh->source = htons(packet->source_port); | |
582 | sh->dest = htons(packet->destination_port); | |
583 | sh->vtag = htonl(packet->vtag); | |
584 | sh->checksum = 0; | |
585 | ||
586 | /* update dst if in need */ | |
587 | if (!sctp_transport_dst_check(tp)) { | |
588 | sctp_transport_route(tp, NULL, sctp_sk(sk)); | |
589 | if (asoc && asoc->param_flags & SPP_PMTUD_ENABLE) | |
590 | sctp_assoc_sync_pmtu(sk, asoc); | |
1da177e4 | 591 | } |
e4ff952a XL |
592 | dst = dst_clone(tp->dst); |
593 | if (!dst) { | |
594 | IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTNOROUTES); | |
595 | kfree_skb(head); | |
596 | goto out; | |
597 | } | |
598 | skb_dst_set(head, dst); | |
1da177e4 | 599 | |
e4ff952a XL |
600 | /* pack up chunks */ |
601 | pkt_count = sctp_packet_pack(packet, head, gso, gfp); | |
602 | if (!pkt_count) { | |
603 | kfree_skb(head); | |
604 | goto out; | |
605 | } | |
90017acc MRL |
606 | pr_debug("***sctp_transmit_packet*** skb->len:%d\n", head->len); |
607 | ||
e4ff952a XL |
608 | /* start autoclose timer */ |
609 | if (packet->has_data && sctp_state(asoc, ESTABLISHED) && | |
610 | asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { | |
611 | struct timer_list *timer = | |
612 | &asoc->timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]; | |
613 | unsigned long timeout = | |
614 | asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]; | |
1da177e4 | 615 | |
e4ff952a XL |
616 | if (!mod_timer(timer, jiffies + timeout)) |
617 | sctp_association_hold(asoc); | |
618 | } | |
90017acc | 619 | |
e4ff952a XL |
620 | /* sctp xmit */ |
621 | tp->af_specific->ecn_capable(sk); | |
622 | if (asoc) { | |
623 | asoc->stats.opackets += pkt_count; | |
624 | if (asoc->peer.last_sent_to != tp) | |
625 | asoc->peer.last_sent_to = tp; | |
90017acc MRL |
626 | } |
627 | head->ignore_df = packet->ipfragok; | |
c86a773c JA |
628 | confirm = tp->dst_pending_confirm; |
629 | if (confirm) | |
630 | skb_set_dst_pending_confirm(head, 1); | |
631 | /* neighbour should be confirmed on successful transmission or | |
632 | * positive error | |
633 | */ | |
634 | if (tp->af_specific->sctp_xmit(head, tp) >= 0 && confirm) | |
635 | tp->dst_pending_confirm = 0; | |
1da177e4 | 636 | |
e4ff952a | 637 | out: |
79af02c2 DM |
638 | list_for_each_entry_safe(chunk, tmp, &packet->chunk_list, list) { |
639 | list_del_init(&chunk->list); | |
1da177e4 | 640 | if (!sctp_chunk_is_data(chunk)) |
d808ad9a | 641 | sctp_chunk_free(chunk); |
1da177e4 | 642 | } |
41001faf | 643 | sctp_packet_reset(packet); |
e4ff952a | 644 | return 0; |
1da177e4 LT |
645 | } |
646 | ||
647 | /******************************************************************** | |
648 | * 2nd Level Abstractions | |
649 | ********************************************************************/ | |
650 | ||
e83963b7 VY |
651 | /* This private function check to see if a chunk can be added */ |
652 | static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet, | |
1da177e4 LT |
653 | struct sctp_chunk *chunk) |
654 | { | |
e83963b7 | 655 | size_t datasize, rwnd, inflight, flight_size; |
1da177e4 | 656 | struct sctp_transport *transport = packet->transport; |
1da177e4 | 657 | struct sctp_association *asoc = transport->asoc; |
1da177e4 LT |
658 | struct sctp_outq *q = &asoc->outqueue; |
659 | ||
660 | /* RFC 2960 6.1 Transmission of DATA Chunks | |
661 | * | |
662 | * A) At any given time, the data sender MUST NOT transmit new data to | |
663 | * any destination transport address if its peer's rwnd indicates | |
664 | * that the peer has no buffer space (i.e. rwnd is 0, see Section | |
665 | * 6.2.1). However, regardless of the value of rwnd (including if it | |
666 | * is 0), the data sender can always have one DATA chunk in flight to | |
667 | * the receiver if allowed by cwnd (see rule B below). This rule | |
668 | * allows the sender to probe for a change in rwnd that the sender | |
669 | * missed due to the SACK having been lost in transit from the data | |
670 | * receiver to the data sender. | |
671 | */ | |
672 | ||
673 | rwnd = asoc->peer.rwnd; | |
e83963b7 VY |
674 | inflight = q->outstanding_bytes; |
675 | flight_size = transport->flight_size; | |
1da177e4 LT |
676 | |
677 | datasize = sctp_data_size(chunk); | |
678 | ||
723189fa DL |
679 | if (datasize > rwnd && 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 | return SCTP_XMIT_RWND_FULL; | |
1da177e4 | 684 | |
1da177e4 LT |
685 | /* RFC 2960 6.1 Transmission of DATA Chunks |
686 | * | |
687 | * B) At any given time, the sender MUST NOT transmit new data | |
688 | * to a given transport address if it has cwnd or more bytes | |
689 | * of data outstanding to that transport address. | |
690 | */ | |
691 | /* RFC 7.2.4 & the Implementers Guide 2.8. | |
692 | * | |
693 | * 3) ... | |
694 | * When a Fast Retransmit is being performed the sender SHOULD | |
695 | * ignore the value of cwnd and SHOULD NOT delay retransmission. | |
696 | */ | |
723189fa DL |
697 | if (chunk->fast_retransmit != SCTP_NEED_FRTX && |
698 | flight_size >= transport->cwnd) | |
699 | return SCTP_XMIT_RWND_FULL; | |
1da177e4 LT |
700 | |
701 | /* Nagle's algorithm to solve small-packet problem: | |
702 | * Inhibit the sending of new chunks when new outgoing data arrives | |
703 | * if any previously transmitted data on the connection remains | |
704 | * unacknowledged. | |
705 | */ | |
1da177e4 | 706 | |
4ea0c32f XL |
707 | if ((sctp_sk(asoc->base.sk)->nodelay || inflight == 0) && |
708 | !chunk->msg->force_delay) | |
709 | /* Nothing unacked */ | |
723189fa DL |
710 | return SCTP_XMIT_OK; |
711 | ||
712 | if (!sctp_packet_empty(packet)) | |
713 | /* Append to packet */ | |
714 | return SCTP_XMIT_OK; | |
715 | ||
723189fa DL |
716 | if (!sctp_state(asoc, ESTABLISHED)) |
717 | return SCTP_XMIT_OK; | |
718 | ||
719 | /* Check whether this chunk and all the rest of pending data will fit | |
720 | * or delay in hopes of bundling a full sized packet. | |
721 | */ | |
e43569e6 MRL |
722 | if (chunk->skb->len + q->out_qlen > |
723 | transport->pathmtu - packet->overhead - sizeof(sctp_data_chunk_t) - 4) | |
723189fa DL |
724 | /* Enough data queued to fill a packet */ |
725 | return SCTP_XMIT_OK; | |
726 | ||
727 | /* Don't delay large message writes that may have been fragmented */ | |
728 | if (!chunk->msg->can_delay) | |
729 | return SCTP_XMIT_OK; | |
730 | ||
731 | /* Defer until all data acked or packet full */ | |
526cbef7 | 732 | return SCTP_XMIT_DELAY; |
e83963b7 VY |
733 | } |
734 | ||
735 | /* This private function does management things when adding DATA chunk */ | |
736 | static void sctp_packet_append_data(struct sctp_packet *packet, | |
737 | struct sctp_chunk *chunk) | |
738 | { | |
739 | struct sctp_transport *transport = packet->transport; | |
740 | size_t datasize = sctp_data_size(chunk); | |
741 | struct sctp_association *asoc = transport->asoc; | |
742 | u32 rwnd = asoc->peer.rwnd; | |
743 | ||
1da177e4 LT |
744 | /* Keep track of how many bytes are in flight over this transport. */ |
745 | transport->flight_size += datasize; | |
746 | ||
747 | /* Keep track of how many bytes are in flight to the receiver. */ | |
748 | asoc->outqueue.outstanding_bytes += datasize; | |
749 | ||
a76c0adf | 750 | /* Update our view of the receiver's rwnd. */ |
1da177e4 LT |
751 | if (datasize < rwnd) |
752 | rwnd -= datasize; | |
753 | else | |
754 | rwnd = 0; | |
755 | ||
756 | asoc->peer.rwnd = rwnd; | |
d8dd1578 NH |
757 | sctp_chunk_assign_tsn(chunk); |
758 | sctp_chunk_assign_ssn(chunk); | |
e83963b7 VY |
759 | } |
760 | ||
761 | static sctp_xmit_t sctp_packet_will_fit(struct sctp_packet *packet, | |
762 | struct sctp_chunk *chunk, | |
763 | u16 chunk_len) | |
764 | { | |
7303a147 | 765 | size_t psize, pmtu, maxsize; |
e83963b7 VY |
766 | sctp_xmit_t retval = SCTP_XMIT_OK; |
767 | ||
768 | psize = packet->size; | |
90017acc MRL |
769 | if (packet->transport->asoc) |
770 | pmtu = packet->transport->asoc->pathmtu; | |
771 | else | |
772 | pmtu = packet->transport->pathmtu; | |
e83963b7 VY |
773 | |
774 | /* Decide if we need to fragment or resubmit later. */ | |
90017acc MRL |
775 | if (psize + chunk_len > pmtu) { |
776 | /* It's OK to fragment at IP level if any one of the following | |
e83963b7 | 777 | * is true: |
90017acc MRL |
778 | * 1. The packet is empty (meaning this chunk is greater |
779 | * the MTU) | |
780 | * 2. The packet doesn't have any data in it yet and data | |
781 | * requires authentication. | |
e83963b7 | 782 | */ |
90017acc | 783 | if (sctp_packet_empty(packet) || |
e83963b7 VY |
784 | (!packet->has_data && chunk->auth)) { |
785 | /* We no longer do re-fragmentation. | |
786 | * Just fragment at the IP layer, if we | |
787 | * actually hit this condition | |
788 | */ | |
789 | packet->ipfragok = 1; | |
90017acc | 790 | goto out; |
e83963b7 | 791 | } |
90017acc | 792 | |
7303a147 MRL |
793 | /* Similarly, if this chunk was built before a PMTU |
794 | * reduction, we have to fragment it at IP level now. So | |
795 | * if the packet already contains something, we need to | |
796 | * flush. | |
797 | */ | |
798 | maxsize = pmtu - packet->overhead; | |
799 | if (packet->auth) | |
e2f036a9 | 800 | maxsize -= SCTP_PAD4(packet->auth->skb->len); |
7303a147 MRL |
801 | if (chunk_len > maxsize) |
802 | retval = SCTP_XMIT_PMTU_FULL; | |
803 | ||
90017acc MRL |
804 | /* It is also okay to fragment if the chunk we are |
805 | * adding is a control chunk, but only if current packet | |
806 | * is not a GSO one otherwise it causes fragmentation of | |
807 | * a large frame. So in this case we allow the | |
808 | * fragmentation by forcing it to be in a new packet. | |
809 | */ | |
810 | if (!sctp_chunk_is_data(chunk) && packet->has_data) | |
811 | retval = SCTP_XMIT_PMTU_FULL; | |
812 | ||
813 | if (psize + chunk_len > packet->max_size) | |
814 | /* Hit GSO/PMTU limit, gotta flush */ | |
815 | retval = SCTP_XMIT_PMTU_FULL; | |
816 | ||
817 | if (!packet->transport->burst_limited && | |
818 | psize + chunk_len > (packet->transport->cwnd >> 1)) | |
819 | /* Do not allow a single GSO packet to use more | |
820 | * than half of cwnd. | |
821 | */ | |
822 | retval = SCTP_XMIT_PMTU_FULL; | |
823 | ||
824 | if (packet->transport->burst_limited && | |
825 | psize + chunk_len > (packet->transport->burst_limited >> 1)) | |
826 | /* Do not allow a single GSO packet to use more | |
827 | * than half of original cwnd. | |
828 | */ | |
829 | retval = SCTP_XMIT_PMTU_FULL; | |
830 | /* Otherwise it will fit in the GSO packet */ | |
e83963b7 | 831 | } |
1da177e4 | 832 | |
90017acc | 833 | out: |
1da177e4 LT |
834 | return retval; |
835 | } |