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Vlad Yasevich60c778b2008-01-11 09:57:09 -05001/* SCTP kernel implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * (C) Copyright IBM Corp. 2003, 2004
3 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -05004 * This file is part of the SCTP kernel implementation
Linus Torvalds1da177e2005-04-16 15:20:36 -07005 *
Michael Opdenacker59c51592007-05-09 08:57:56 +02006 * This file contains the code relating the chunk abstraction.
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -05008 * This SCTP implementation is free software;
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 * 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 *
Vlad Yasevich60c778b2008-01-11 09:57:09 -050014 * This SCTP implementation is distributed in the hope that it
Linus Torvalds1da177e2005-04-16 15:20:36 -070015 * 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
21 * along with GNU CC; see the file COPYING. If not, write to
22 * the Free Software Foundation, 59 Temple Place - Suite 330,
23 * Boston, MA 02111-1307, USA.
24 *
25 * Please send any bug reports or fixes you make to the
26 * email address(es):
27 * lksctp developers <lksctp-developers@lists.sourceforge.net>
28 *
29 * Or submit a bug report through the following website:
30 * http://www.sf.net/projects/lksctp
31 *
32 * Written or modified by:
33 * Jon Grimm <jgrimm@us.ibm.com>
34 * Sridhar Samudrala <sri@us.ibm.com>
35 *
36 * Any bugs reported given to us we will try to fix... any fixes shared will
37 * be incorporated into the next SCTP release.
38 */
39
40#include <linux/types.h>
41#include <linux/kernel.h>
42#include <linux/net.h>
43#include <linux/inet.h>
44#include <linux/skbuff.h>
45#include <net/sock.h>
46#include <net/sctp/sctp.h>
47#include <net/sctp/sm.h>
48
49/* This file is mostly in anticipation of future work, but initially
50 * populate with fragment tracking for an outbound message.
51 */
52
53/* Initialize datamsg from memory. */
54static void sctp_datamsg_init(struct sctp_datamsg *msg)
55{
56 atomic_set(&msg->refcnt, 1);
57 msg->send_failed = 0;
58 msg->send_error = 0;
59 msg->can_abandon = 0;
60 msg->expires_at = 0;
61 INIT_LIST_HEAD(&msg->chunks);
Vlad Yasevichcb95ea32009-09-04 18:20:59 -040062 msg->msg_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070063}
64
65/* Allocate and initialize datamsg. */
Al Virodd0fc662005-10-07 07:46:04 +010066SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -070067{
68 struct sctp_datamsg *msg;
69 msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
Li Zefane8c38752008-04-10 01:57:24 -070070 if (msg) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 sctp_datamsg_init(msg);
Li Zefane8c38752008-04-10 01:57:24 -070072 SCTP_DBG_OBJCNT_INC(datamsg);
73 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 return msg;
75}
76
Vlad Yasevich9c5c62b2009-08-10 13:51:03 -040077void sctp_datamsg_free(struct sctp_datamsg *msg)
78{
79 struct sctp_chunk *chunk;
80
81 /* This doesn't have to be a _safe vairant because
82 * sctp_chunk_free() only drops the refs.
83 */
84 list_for_each_entry(chunk, &msg->chunks, frag_list)
85 sctp_chunk_free(chunk);
86
87 sctp_datamsg_put(msg);
88}
89
Linus Torvalds1da177e2005-04-16 15:20:36 -070090/* Final destructruction of datamsg memory. */
91static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
92{
93 struct list_head *pos, *temp;
94 struct sctp_chunk *chunk;
95 struct sctp_sock *sp;
96 struct sctp_ulpevent *ev;
97 struct sctp_association *asoc = NULL;
98 int error = 0, notify;
99
100 /* If we failed, we may need to notify. */
101 notify = msg->send_failed ? -1 : 0;
102
103 /* Release all references. */
104 list_for_each_safe(pos, temp, &msg->chunks) {
105 list_del_init(pos);
106 chunk = list_entry(pos, struct sctp_chunk, frag_list);
107 /* Check whether we _really_ need to notify. */
108 if (notify < 0) {
109 asoc = chunk->asoc;
110 if (msg->send_error)
111 error = msg->send_error;
112 else
113 error = asoc->outqueue.error;
114
115 sp = sctp_sk(asoc->base.sk);
116 notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
117 &sp->subscribe);
118 }
119
120 /* Generate a SEND FAILED event only if enabled. */
121 if (notify > 0) {
122 int sent;
123 if (chunk->has_tsn)
124 sent = SCTP_DATA_SENT;
125 else
126 sent = SCTP_DATA_UNSENT;
127
128 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
129 error, GFP_ATOMIC);
130 if (ev)
131 sctp_ulpq_tail_event(&asoc->ulpq, ev);
132 }
133
134 sctp_chunk_put(chunk);
135 }
136
137 SCTP_DBG_OBJCNT_DEC(datamsg);
138 kfree(msg);
139}
140
141/* Hold a reference. */
142static void sctp_datamsg_hold(struct sctp_datamsg *msg)
143{
144 atomic_inc(&msg->refcnt);
145}
146
147/* Release a reference. */
148void sctp_datamsg_put(struct sctp_datamsg *msg)
149{
150 if (atomic_dec_and_test(&msg->refcnt))
151 sctp_datamsg_destroy(msg);
152}
153
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154/* Assign a chunk to this datamsg. */
155static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
156{
157 sctp_datamsg_hold(msg);
158 chunk->msg = msg;
Vlad Yasevichcb95ea32009-09-04 18:20:59 -0400159 msg->msg_size += chunk->skb->len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160}
161
162
163/* A data chunk can have a maximum payload of (2^16 - 20). Break
164 * down any such message into smaller chunks. Opportunistically, fragment
165 * the chunks down to the current MTU constraints. We may get refragmented
166 * later if the PMTU changes, but it is _much better_ to fragment immediately
167 * with a reasonable guess than always doing our fragmentation on the
168 * soft-interrupt.
169 */
170struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
171 struct sctp_sndrcvinfo *sinfo,
172 struct msghdr *msgh, int msg_len)
173{
174 int max, whole, i, offset, over, err;
175 int len, first_len;
Vlad Yasevich3e62abf2009-09-04 18:20:56 -0400176 int max_data;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 struct sctp_chunk *chunk;
178 struct sctp_datamsg *msg;
179 struct list_head *pos, *temp;
180 __u8 frag;
181
182 msg = sctp_datamsg_new(GFP_KERNEL);
183 if (!msg)
184 return NULL;
185
186 /* Note: Calculate this outside of the loop, so that all fragments
187 * have the same expiration.
188 */
189 if (sinfo->sinfo_timetolive) {
190 /* sinfo_timetolive is in milliseconds */
191 msg->expires_at = jiffies +
192 msecs_to_jiffies(sinfo->sinfo_timetolive);
193 msg->can_abandon = 1;
194 SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n",
Harvey Harrison0dc47872008-03-05 20:47:47 -0800195 __func__, msg, msg->expires_at, jiffies);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196 }
197
Vlad Yasevich3e62abf2009-09-04 18:20:56 -0400198 /* This is the biggest possible DATA chunk that can fit into
199 * the packet
200 */
201 max_data = asoc->pathmtu -
202 sctp_sk(asoc->base.sk)->pf->af->net_header_len -
203 sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204
Vlad Yasevich3e62abf2009-09-04 18:20:56 -0400205 max = asoc->frag_point;
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700206 /* If the the peer requested that we authenticate DATA chunks
207 * we need to accound for bundling of the AUTH chunks along with
208 * DATA.
209 */
210 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
211 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
212
213 if (hmac_desc)
Vlad Yasevich3e62abf2009-09-04 18:20:56 -0400214 max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700215 hmac_desc->hmac_len);
216 }
217
Vlad Yasevich3e62abf2009-09-04 18:20:56 -0400218 /* Now, check if we need to reduce our max */
219 if (max > max_data)
220 max = max_data;
221
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 whole = 0;
223 first_len = max;
224
Vlad Yasevich5d7ff262009-08-07 13:23:28 -0400225 /* Check to see if we have a pending SACK and try to let it be bundled
226 * with this message. Do this if we don't have any data queued already.
227 * To check that, look at out_qlen and retransmit list.
228 * NOTE: we will not reduce to account for SACK, if the message would
229 * not have been fragmented.
230 */
231 if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) &&
232 asoc->outqueue.out_qlen == 0 &&
233 list_empty(&asoc->outqueue.retransmit) &&
234 msg_len > max)
235 max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t));
236
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 /* Encourage Cookie-ECHO bundling. */
Vlad Yasevich5d7ff262009-08-07 13:23:28 -0400238 if (asoc->state < SCTP_STATE_COOKIE_ECHOED)
Vlad Yasevich3e62abf2009-09-04 18:20:56 -0400239 max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240
Vlad Yasevich5d7ff262009-08-07 13:23:28 -0400241 /* Now that we adjusted completely, reset first_len */
242 if (first_len > max_data)
243 first_len = max_data;
Vlad Yasevich3e62abf2009-09-04 18:20:56 -0400244
245 /* Account for a different sized first fragment */
246 if (msg_len >= first_len) {
247 msg_len -= first_len;
248 whole = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 }
250
251 /* How many full sized? How many bytes leftover? */
252 whole += msg_len / max;
253 over = msg_len % max;
254 offset = 0;
255
256 if ((whole > 1) || (whole && over))
257 SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS);
258
259 /* Create chunks for all the full sized DATA chunks. */
260 for (i=0, len=first_len; i < whole; i++) {
261 frag = SCTP_DATA_MIDDLE_FRAG;
262
263 if (0 == i)
264 frag |= SCTP_DATA_FIRST_FRAG;
265
266 if ((i == (whole - 1)) && !over)
267 frag |= SCTP_DATA_LAST_FRAG;
268
269 chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
270
271 if (!chunk)
272 goto errout;
273 err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
274 if (err < 0)
275 goto errout;
276
277 offset += len;
278
279 /* Put the chunk->skb back into the form expected by send. */
280 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
281 - (__u8 *)chunk->skb->data);
282
283 sctp_datamsg_assign(msg, chunk);
284 list_add_tail(&chunk->frag_list, &msg->chunks);
285
286 /* The first chunk, the first chunk was likely short
287 * to allow bundling, so reset to full size.
288 */
289 if (0 == i)
290 len = max;
291 }
292
293 /* .. now the leftover bytes. */
294 if (over) {
295 if (!whole)
296 frag = SCTP_DATA_NOT_FRAG;
297 else
298 frag = SCTP_DATA_LAST_FRAG;
299
300 chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
301
302 if (!chunk)
303 goto errout;
304
305 err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov);
306
307 /* Put the chunk->skb back into the form expected by send. */
308 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
309 - (__u8 *)chunk->skb->data);
310 if (err < 0)
311 goto errout;
312
313 sctp_datamsg_assign(msg, chunk);
314 list_add_tail(&chunk->frag_list, &msg->chunks);
315 }
316
317 return msg;
318
319errout:
320 list_for_each_safe(pos, temp, &msg->chunks) {
321 list_del_init(pos);
322 chunk = list_entry(pos, struct sctp_chunk, frag_list);
323 sctp_chunk_free(chunk);
324 }
Florian Westphal80445cf2008-03-23 22:47:08 -0700325 sctp_datamsg_put(msg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 return NULL;
327}
328
329/* Check whether this message has expired. */
330int sctp_chunk_abandoned(struct sctp_chunk *chunk)
331{
332 struct sctp_datamsg *msg = chunk->msg;
333
334 if (!msg->can_abandon)
335 return 0;
336
337 if (time_after(jiffies, msg->expires_at))
338 return 1;
339
340 return 0;
341}
342
343/* This chunk (and consequently entire message) has failed in its sending. */
344void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
345{
346 chunk->msg->send_failed = 1;
347 chunk->msg->send_error = error;
348}