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60c778b2 1/* SCTP kernel implementation
1da177e4
LT
2 * (C) Copyright IBM Corp. 2003, 2004
3 *
60c778b2 4 * This file is part of the SCTP kernel implementation
1da177e4 5 *
59c51591 6 * This file contains the code relating the chunk abstraction.
1da177e4 7 *
60c778b2 8 * This SCTP implementation is free software;
1da177e4
LT
9 * you can redistribute it and/or modify it under the terms of
10 * the GNU General Public License as published by
11 * the Free Software Foundation; either version 2, or (at your option)
12 * any later version.
13 *
60c778b2 14 * This SCTP implementation is distributed in the hope that it
1da177e4
LT
15 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
16 * ************************
17 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
18 * See the GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
4b2f13a2
JK
21 * along with GNU CC; see the file COPYING. If not, see
22 * <http://www.gnu.org/licenses/>.
1da177e4
LT
23 *
24 * Please send any bug reports or fixes you make to the
25 * email address(es):
91705c61 26 * lksctp developers <linux-sctp@vger.kernel.org>
1da177e4 27 *
1da177e4
LT
28 * Written or modified by:
29 * Jon Grimm <jgrimm@us.ibm.com>
30 * Sridhar Samudrala <sri@us.ibm.com>
1da177e4
LT
31 */
32
145ce502
JP
33#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
34
1da177e4
LT
35#include <linux/types.h>
36#include <linux/kernel.h>
37#include <linux/net.h>
38#include <linux/inet.h>
39#include <linux/skbuff.h>
5a0e3ad6 40#include <linux/slab.h>
1da177e4
LT
41#include <net/sock.h>
42#include <net/sctp/sctp.h>
43#include <net/sctp/sm.h>
44
45/* This file is mostly in anticipation of future work, but initially
46 * populate with fragment tracking for an outbound message.
47 */
48
49/* Initialize datamsg from memory. */
50static void sctp_datamsg_init(struct sctp_datamsg *msg)
51{
52 atomic_set(&msg->refcnt, 1);
53 msg->send_failed = 0;
54 msg->send_error = 0;
0e3aef8d 55 msg->can_delay = 1;
1da177e4
LT
56 msg->expires_at = 0;
57 INIT_LIST_HEAD(&msg->chunks);
58}
59
60/* Allocate and initialize datamsg. */
dda91928 61static struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
1da177e4
LT
62{
63 struct sctp_datamsg *msg;
64 msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
e8c38751 65 if (msg) {
1da177e4 66 sctp_datamsg_init(msg);
e8c38751
LZ
67 SCTP_DBG_OBJCNT_INC(datamsg);
68 }
1da177e4
LT
69 return msg;
70}
71
b61c654f
XL
72void sctp_datamsg_free(struct sctp_datamsg *msg)
73{
74 struct sctp_chunk *chunk;
75
76 /* This doesn't have to be a _safe vairant because
77 * sctp_chunk_free() only drops the refs.
78 */
79 list_for_each_entry(chunk, &msg->chunks, frag_list)
80 sctp_chunk_free(chunk);
81
82 sctp_datamsg_put(msg);
83}
84
1da177e4
LT
85/* Final destructruction of datamsg memory. */
86static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
87{
88 struct list_head *pos, *temp;
89 struct sctp_chunk *chunk;
90 struct sctp_sock *sp;
91 struct sctp_ulpevent *ev;
92 struct sctp_association *asoc = NULL;
93 int error = 0, notify;
94
95 /* If we failed, we may need to notify. */
96 notify = msg->send_failed ? -1 : 0;
97
98 /* Release all references. */
99 list_for_each_safe(pos, temp, &msg->chunks) {
100 list_del_init(pos);
101 chunk = list_entry(pos, struct sctp_chunk, frag_list);
102 /* Check whether we _really_ need to notify. */
103 if (notify < 0) {
104 asoc = chunk->asoc;
105 if (msg->send_error)
106 error = msg->send_error;
107 else
108 error = asoc->outqueue.error;
109
110 sp = sctp_sk(asoc->base.sk);
111 notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
112 &sp->subscribe);
113 }
114
115 /* Generate a SEND FAILED event only if enabled. */
116 if (notify > 0) {
117 int sent;
118 if (chunk->has_tsn)
119 sent = SCTP_DATA_SENT;
120 else
121 sent = SCTP_DATA_UNSENT;
122
123 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
124 error, GFP_ATOMIC);
125 if (ev)
126 sctp_ulpq_tail_event(&asoc->ulpq, ev);
127 }
128
129 sctp_chunk_put(chunk);
130 }
131
132 SCTP_DBG_OBJCNT_DEC(datamsg);
133 kfree(msg);
134}
135
136/* Hold a reference. */
137static void sctp_datamsg_hold(struct sctp_datamsg *msg)
138{
139 atomic_inc(&msg->refcnt);
140}
141
142/* Release a reference. */
143void sctp_datamsg_put(struct sctp_datamsg *msg)
144{
145 if (atomic_dec_and_test(&msg->refcnt))
146 sctp_datamsg_destroy(msg);
147}
148
1da177e4
LT
149/* Assign a chunk to this datamsg. */
150static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
151{
152 sctp_datamsg_hold(msg);
153 chunk->msg = msg;
154}
155
156
157/* A data chunk can have a maximum payload of (2^16 - 20). Break
158 * down any such message into smaller chunks. Opportunistically, fragment
159 * the chunks down to the current MTU constraints. We may get refragmented
160 * later if the PMTU changes, but it is _much better_ to fragment immediately
161 * with a reasonable guess than always doing our fragmentation on the
162 * soft-interrupt.
163 */
164struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
165 struct sctp_sndrcvinfo *sinfo,
e0eb093e 166 struct iov_iter *from)
1da177e4 167{
bfd2e4b8
MRL
168 size_t len, first_len, max_data, remaining;
169 size_t msg_len = iov_iter_count(from);
170 struct list_head *pos, *temp;
1da177e4
LT
171 struct sctp_chunk *chunk;
172 struct sctp_datamsg *msg;
bfd2e4b8 173 int err;
1da177e4
LT
174
175 msg = sctp_datamsg_new(GFP_KERNEL);
176 if (!msg)
6e51fe75 177 return ERR_PTR(-ENOMEM);
1da177e4
LT
178
179 /* Note: Calculate this outside of the loop, so that all fragments
180 * have the same expiration.
181 */
8ae808eb
XL
182 if (asoc->peer.prsctp_capable && sinfo->sinfo_timetolive &&
183 (SCTP_PR_TTL_ENABLED(sinfo->sinfo_flags) ||
184 !SCTP_PR_POLICY(sinfo->sinfo_flags)))
1da177e4 185 msg->expires_at = jiffies +
bfd2e4b8 186 msecs_to_jiffies(sinfo->sinfo_timetolive);
0605483f 187
3e62abf9
VY
188 /* This is the biggest possible DATA chunk that can fit into
189 * the packet
190 */
4a225ce3
MRL
191 max_data = asoc->pathmtu -
192 sctp_sk(asoc->base.sk)->pf->af->net_header_len -
193 sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk);
194 max_data = SCTP_TRUNC4(max_data);
1da177e4 195
4cd57c80 196 /* If the the peer requested that we authenticate DATA chunks
2bccbadf 197 * we need to account for bundling of the AUTH chunks along with
4cd57c80
VY
198 * DATA.
199 */
200 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
201 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
202
203 if (hmac_desc)
e2f036a9
MRL
204 max_data -= SCTP_PAD4(sizeof(sctp_auth_chunk_t) +
205 hmac_desc->hmac_len);
4cd57c80
VY
206 }
207
bfd2e4b8
MRL
208 /* Check what's our max considering the above */
209 max_data = min_t(size_t, max_data, asoc->frag_point);
3e62abf9 210
bfd2e4b8
MRL
211 /* Set first_len and then account for possible bundles on first frag */
212 first_len = max_data;
1da177e4 213
5d7ff261
VY
214 /* Check to see if we have a pending SACK and try to let it be bundled
215 * with this message. Do this if we don't have any data queued already.
216 * To check that, look at out_qlen and retransmit list.
217 * NOTE: we will not reduce to account for SACK, if the message would
218 * not have been fragmented.
219 */
220 if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) &&
221 asoc->outqueue.out_qlen == 0 &&
222 list_empty(&asoc->outqueue.retransmit) &&
bfd2e4b8
MRL
223 msg_len > max_data)
224 first_len -= SCTP_PAD4(sizeof(sctp_sack_chunk_t));
5d7ff261 225
1da177e4 226 /* Encourage Cookie-ECHO bundling. */
5d7ff261 227 if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
bfd2e4b8 228 first_len -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
3e62abf9
VY
229
230 /* Account for a different sized first fragment */
231 if (msg_len >= first_len) {
0e3aef8d 232 msg->can_delay = 0;
6aef70a8 233 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_FRAGUSRMSGS);
bfd2e4b8
MRL
234 } else {
235 /* Which may be the only one... */
236 first_len = msg_len;
237 }
1da177e4 238
bfd2e4b8
MRL
239 /* Create chunks for all DATA chunks. */
240 for (remaining = msg_len; remaining; remaining -= len) {
241 u8 frag = SCTP_DATA_MIDDLE_FRAG;
1da177e4 242
bfd2e4b8
MRL
243 if (remaining == msg_len) {
244 /* First frag, which may also be the last */
1da177e4 245 frag |= SCTP_DATA_FIRST_FRAG;
bfd2e4b8
MRL
246 len = first_len;
247 } else {
248 /* Middle frags */
249 len = max_data;
250 }
1da177e4 251
bfd2e4b8
MRL
252 if (len >= remaining) {
253 /* Last frag, which may also be the first */
254 len = remaining;
1da177e4
LT
255 frag |= SCTP_DATA_LAST_FRAG;
256
b93d6471
WY
257 /* The application requests to set the I-bit of the
258 * last DATA chunk of a user message when providing
259 * the user message to the SCTP implementation.
260 */
261 if ((sinfo->sinfo_flags & SCTP_EOF) ||
262 (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY))
263 frag |= SCTP_DATA_SACK_IMM;
264 }
265
cea8768f
MRL
266 chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag,
267 0, GFP_KERNEL);
6e51fe75
TR
268 if (!chunk) {
269 err = -ENOMEM;
1da177e4 270 goto errout;
6e51fe75
TR
271 }
272
e0eb093e 273 err = sctp_user_addto_chunk(chunk, len, from);
1da177e4 274 if (err < 0)
be364c8c 275 goto errout_chunk_free;
1da177e4 276
1da177e4 277 /* Put the chunk->skb back into the form expected by send. */
bfd2e4b8
MRL
278 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr -
279 chunk->skb->data);
1da177e4
LT
280
281 sctp_datamsg_assign(msg, chunk);
282 list_add_tail(&chunk->frag_list, &msg->chunks);
283 }
284
285 return msg;
286
be364c8c
TR
287errout_chunk_free:
288 sctp_chunk_free(chunk);
289
1da177e4
LT
290errout:
291 list_for_each_safe(pos, temp, &msg->chunks) {
292 list_del_init(pos);
293 chunk = list_entry(pos, struct sctp_chunk, frag_list);
294 sctp_chunk_free(chunk);
295 }
80445cfb 296 sctp_datamsg_put(msg);
bfd2e4b8 297
6e51fe75 298 return ERR_PTR(err);
1da177e4
LT
299}
300
301/* Check whether this message has expired. */
302int sctp_chunk_abandoned(struct sctp_chunk *chunk)
303{
8ae808eb 304 if (!chunk->asoc->peer.prsctp_capable)
1da177e4
LT
305 return 0;
306
a6c2f792 307 if (SCTP_PR_TTL_ENABLED(chunk->sinfo.sinfo_flags) &&
0605483f 308 time_after(jiffies, chunk->msg->expires_at)) {
d229d48d 309 struct sctp_stream_out *streamout =
cee360ab 310 &chunk->asoc->stream.out[chunk->sinfo.sinfo_stream];
d229d48d
XL
311
312 if (chunk->sent_count) {
a6c2f792 313 chunk->asoc->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
d229d48d
XL
314 streamout->abandoned_sent[SCTP_PR_INDEX(TTL)]++;
315 } else {
a6c2f792 316 chunk->asoc->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
d229d48d
XL
317 streamout->abandoned_unsent[SCTP_PR_INDEX(TTL)]++;
318 }
1da177e4 319 return 1;
01aadb3a 320 } else if (SCTP_PR_RTX_ENABLED(chunk->sinfo.sinfo_flags) &&
0605483f 321 chunk->sent_count > chunk->sinfo.sinfo_timetolive) {
d229d48d 322 struct sctp_stream_out *streamout =
cee360ab 323 &chunk->asoc->stream.out[chunk->sinfo.sinfo_stream];
d229d48d 324
01aadb3a 325 chunk->asoc->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
d229d48d 326 streamout->abandoned_sent[SCTP_PR_INDEX(RTX)]++;
01aadb3a 327 return 1;
8ae808eb
XL
328 } else if (!SCTP_PR_POLICY(chunk->sinfo.sinfo_flags) &&
329 chunk->msg->expires_at &&
330 time_after(jiffies, chunk->msg->expires_at)) {
331 return 1;
a6c2f792 332 }
8dbdf1f5 333 /* PRIO policy is processed by sendmsg, not here */
1da177e4
LT
334
335 return 0;
336}
337
338/* This chunk (and consequently entire message) has failed in its sending. */
339void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
340{
341 chunk->msg->send_failed = 1;
342 chunk->msg->send_error = error;
343}