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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* SCTP kernel reference Implementation
2 * (C) Copyright IBM Corp. 2003, 2004
3 *
4 * This file is part of the SCTP kernel reference Implementation
5 *
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 *
8 * The SCTP reference implementation is free software;
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 *
14 * The SCTP reference implementation is distributed in the hope that it
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
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);
62}
63
64/* Allocate and initialize datamsg. */
Al Virodd0fc662005-10-07 07:46:04 +010065SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -070066{
67 struct sctp_datamsg *msg;
68 msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
69 if (msg)
70 sctp_datamsg_init(msg);
71 SCTP_DBG_OBJCNT_INC(datamsg);
72 return msg;
73}
74
75/* Final destructruction of datamsg memory. */
76static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
77{
78 struct list_head *pos, *temp;
79 struct sctp_chunk *chunk;
80 struct sctp_sock *sp;
81 struct sctp_ulpevent *ev;
82 struct sctp_association *asoc = NULL;
83 int error = 0, notify;
84
85 /* If we failed, we may need to notify. */
86 notify = msg->send_failed ? -1 : 0;
87
88 /* Release all references. */
89 list_for_each_safe(pos, temp, &msg->chunks) {
90 list_del_init(pos);
91 chunk = list_entry(pos, struct sctp_chunk, frag_list);
92 /* Check whether we _really_ need to notify. */
93 if (notify < 0) {
94 asoc = chunk->asoc;
95 if (msg->send_error)
96 error = msg->send_error;
97 else
98 error = asoc->outqueue.error;
99
100 sp = sctp_sk(asoc->base.sk);
101 notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
102 &sp->subscribe);
103 }
104
105 /* Generate a SEND FAILED event only if enabled. */
106 if (notify > 0) {
107 int sent;
108 if (chunk->has_tsn)
109 sent = SCTP_DATA_SENT;
110 else
111 sent = SCTP_DATA_UNSENT;
112
113 ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
114 error, GFP_ATOMIC);
115 if (ev)
116 sctp_ulpq_tail_event(&asoc->ulpq, ev);
117 }
118
119 sctp_chunk_put(chunk);
120 }
121
122 SCTP_DBG_OBJCNT_DEC(datamsg);
123 kfree(msg);
124}
125
126/* Hold a reference. */
127static void sctp_datamsg_hold(struct sctp_datamsg *msg)
128{
129 atomic_inc(&msg->refcnt);
130}
131
132/* Release a reference. */
133void sctp_datamsg_put(struct sctp_datamsg *msg)
134{
135 if (atomic_dec_and_test(&msg->refcnt))
136 sctp_datamsg_destroy(msg);
137}
138
139/* Free a message. Really just give up a reference, the
140 * really free happens in sctp_datamsg_destroy().
141 */
142void sctp_datamsg_free(struct sctp_datamsg *msg)
143{
144 sctp_datamsg_put(msg);
145}
146
147/* Hold on to all the fragments until all chunks have been sent. */
148void sctp_datamsg_track(struct sctp_chunk *chunk)
149{
150 sctp_chunk_hold(chunk);
151}
152
153/* Assign a chunk to this datamsg. */
154static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
155{
156 sctp_datamsg_hold(msg);
157 chunk->msg = msg;
158}
159
160
161/* A data chunk can have a maximum payload of (2^16 - 20). Break
162 * down any such message into smaller chunks. Opportunistically, fragment
163 * the chunks down to the current MTU constraints. We may get refragmented
164 * later if the PMTU changes, but it is _much better_ to fragment immediately
165 * with a reasonable guess than always doing our fragmentation on the
166 * soft-interrupt.
167 */
168struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
169 struct sctp_sndrcvinfo *sinfo,
170 struct msghdr *msgh, int msg_len)
171{
172 int max, whole, i, offset, over, err;
173 int len, first_len;
174 struct sctp_chunk *chunk;
175 struct sctp_datamsg *msg;
176 struct list_head *pos, *temp;
177 __u8 frag;
178
179 msg = sctp_datamsg_new(GFP_KERNEL);
180 if (!msg)
181 return NULL;
182
183 /* Note: Calculate this outside of the loop, so that all fragments
184 * have the same expiration.
185 */
186 if (sinfo->sinfo_timetolive) {
187 /* sinfo_timetolive is in milliseconds */
188 msg->expires_at = jiffies +
189 msecs_to_jiffies(sinfo->sinfo_timetolive);
190 msg->can_abandon = 1;
191 SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n",
192 __FUNCTION__, msg, msg->expires_at, jiffies);
193 }
194
195 max = asoc->frag_point;
196
Vlad Yasevich4cd57c82007-09-16 19:32:45 -0700197 /* If the the peer requested that we authenticate DATA chunks
198 * we need to accound for bundling of the AUTH chunks along with
199 * DATA.
200 */
201 if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
202 struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
203
204 if (hmac_desc)
205 max -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
206 hmac_desc->hmac_len);
207 }
208
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 whole = 0;
210 first_len = max;
211
212 /* Encourage Cookie-ECHO bundling. */
213 if (asoc->state < SCTP_STATE_COOKIE_ECHOED) {
214 whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN);
215
216 /* Account for the DATA to be bundled with the COOKIE-ECHO. */
217 if (whole) {
218 first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN;
219 msg_len -= first_len;
220 whole = 1;
221 }
222 }
223
224 /* How many full sized? How many bytes leftover? */
225 whole += msg_len / max;
226 over = msg_len % max;
227 offset = 0;
228
229 if ((whole > 1) || (whole && over))
230 SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS);
231
232 /* Create chunks for all the full sized DATA chunks. */
233 for (i=0, len=first_len; i < whole; i++) {
234 frag = SCTP_DATA_MIDDLE_FRAG;
235
236 if (0 == i)
237 frag |= SCTP_DATA_FIRST_FRAG;
238
239 if ((i == (whole - 1)) && !over)
240 frag |= SCTP_DATA_LAST_FRAG;
241
242 chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
243
244 if (!chunk)
245 goto errout;
246 err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
247 if (err < 0)
248 goto errout;
249
250 offset += len;
251
252 /* Put the chunk->skb back into the form expected by send. */
253 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
254 - (__u8 *)chunk->skb->data);
255
256 sctp_datamsg_assign(msg, chunk);
257 list_add_tail(&chunk->frag_list, &msg->chunks);
258
259 /* The first chunk, the first chunk was likely short
260 * to allow bundling, so reset to full size.
261 */
262 if (0 == i)
263 len = max;
264 }
265
266 /* .. now the leftover bytes. */
267 if (over) {
268 if (!whole)
269 frag = SCTP_DATA_NOT_FRAG;
270 else
271 frag = SCTP_DATA_LAST_FRAG;
272
273 chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
274
275 if (!chunk)
276 goto errout;
277
278 err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov);
279
280 /* Put the chunk->skb back into the form expected by send. */
281 __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
282 - (__u8 *)chunk->skb->data);
283 if (err < 0)
284 goto errout;
285
286 sctp_datamsg_assign(msg, chunk);
287 list_add_tail(&chunk->frag_list, &msg->chunks);
288 }
289
290 return msg;
291
292errout:
293 list_for_each_safe(pos, temp, &msg->chunks) {
294 list_del_init(pos);
295 chunk = list_entry(pos, struct sctp_chunk, frag_list);
296 sctp_chunk_free(chunk);
297 }
298 sctp_datamsg_free(msg);
299 return NULL;
300}
301
302/* Check whether this message has expired. */
303int sctp_chunk_abandoned(struct sctp_chunk *chunk)
304{
305 struct sctp_datamsg *msg = chunk->msg;
306
307 if (!msg->can_abandon)
308 return 0;
309
310 if (time_after(jiffies, msg->expires_at))
311 return 1;
312
313 return 0;
314}
315
316/* This chunk (and consequently entire message) has failed in its sending. */
317void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
318{
319 chunk->msg->send_failed = 1;
320 chunk->msg->send_error = error;
321}