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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 | |
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. */ | |
54 | static 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. */ | |
dd0fc66f | 65 | SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) |
1da177e4 LT |
66 | { |
67 | struct sctp_datamsg *msg; | |
68 | msg = kmalloc(sizeof(struct sctp_datamsg), gfp); | |
e8c38751 | 69 | if (msg) { |
1da177e4 | 70 | sctp_datamsg_init(msg); |
e8c38751 LZ |
71 | SCTP_DBG_OBJCNT_INC(datamsg); |
72 | } | |
1da177e4 LT |
73 | return msg; |
74 | } | |
75 | ||
76 | /* Final destructruction of datamsg memory. */ | |
77 | static void sctp_datamsg_destroy(struct sctp_datamsg *msg) | |
78 | { | |
79 | struct list_head *pos, *temp; | |
80 | struct sctp_chunk *chunk; | |
81 | struct sctp_sock *sp; | |
82 | struct sctp_ulpevent *ev; | |
83 | struct sctp_association *asoc = NULL; | |
84 | int error = 0, notify; | |
85 | ||
86 | /* If we failed, we may need to notify. */ | |
87 | notify = msg->send_failed ? -1 : 0; | |
88 | ||
89 | /* Release all references. */ | |
90 | list_for_each_safe(pos, temp, &msg->chunks) { | |
91 | list_del_init(pos); | |
92 | chunk = list_entry(pos, struct sctp_chunk, frag_list); | |
93 | /* Check whether we _really_ need to notify. */ | |
94 | if (notify < 0) { | |
95 | asoc = chunk->asoc; | |
96 | if (msg->send_error) | |
97 | error = msg->send_error; | |
98 | else | |
99 | error = asoc->outqueue.error; | |
100 | ||
101 | sp = sctp_sk(asoc->base.sk); | |
102 | notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED, | |
103 | &sp->subscribe); | |
104 | } | |
105 | ||
106 | /* Generate a SEND FAILED event only if enabled. */ | |
107 | if (notify > 0) { | |
108 | int sent; | |
109 | if (chunk->has_tsn) | |
110 | sent = SCTP_DATA_SENT; | |
111 | else | |
112 | sent = SCTP_DATA_UNSENT; | |
113 | ||
114 | ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, | |
115 | error, GFP_ATOMIC); | |
116 | if (ev) | |
117 | sctp_ulpq_tail_event(&asoc->ulpq, ev); | |
118 | } | |
119 | ||
120 | sctp_chunk_put(chunk); | |
121 | } | |
122 | ||
123 | SCTP_DBG_OBJCNT_DEC(datamsg); | |
124 | kfree(msg); | |
125 | } | |
126 | ||
127 | /* Hold a reference. */ | |
128 | static void sctp_datamsg_hold(struct sctp_datamsg *msg) | |
129 | { | |
130 | atomic_inc(&msg->refcnt); | |
131 | } | |
132 | ||
133 | /* Release a reference. */ | |
134 | void sctp_datamsg_put(struct sctp_datamsg *msg) | |
135 | { | |
136 | if (atomic_dec_and_test(&msg->refcnt)) | |
137 | sctp_datamsg_destroy(msg); | |
138 | } | |
139 | ||
1da177e4 LT |
140 | /* Assign a chunk to this datamsg. */ |
141 | static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) | |
142 | { | |
143 | sctp_datamsg_hold(msg); | |
144 | chunk->msg = msg; | |
145 | } | |
146 | ||
147 | ||
148 | /* A data chunk can have a maximum payload of (2^16 - 20). Break | |
149 | * down any such message into smaller chunks. Opportunistically, fragment | |
150 | * the chunks down to the current MTU constraints. We may get refragmented | |
151 | * later if the PMTU changes, but it is _much better_ to fragment immediately | |
152 | * with a reasonable guess than always doing our fragmentation on the | |
153 | * soft-interrupt. | |
154 | */ | |
155 | struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, | |
156 | struct sctp_sndrcvinfo *sinfo, | |
157 | struct msghdr *msgh, int msg_len) | |
158 | { | |
159 | int max, whole, i, offset, over, err; | |
160 | int len, first_len; | |
3e62abf9 | 161 | int max_data; |
1da177e4 LT |
162 | struct sctp_chunk *chunk; |
163 | struct sctp_datamsg *msg; | |
164 | struct list_head *pos, *temp; | |
165 | __u8 frag; | |
166 | ||
167 | msg = sctp_datamsg_new(GFP_KERNEL); | |
168 | if (!msg) | |
169 | return NULL; | |
170 | ||
171 | /* Note: Calculate this outside of the loop, so that all fragments | |
172 | * have the same expiration. | |
173 | */ | |
174 | if (sinfo->sinfo_timetolive) { | |
175 | /* sinfo_timetolive is in milliseconds */ | |
176 | msg->expires_at = jiffies + | |
177 | msecs_to_jiffies(sinfo->sinfo_timetolive); | |
178 | msg->can_abandon = 1; | |
179 | SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n", | |
0dc47877 | 180 | __func__, msg, msg->expires_at, jiffies); |
1da177e4 LT |
181 | } |
182 | ||
3e62abf9 VY |
183 | /* This is the biggest possible DATA chunk that can fit into |
184 | * the packet | |
185 | */ | |
186 | max_data = asoc->pathmtu - | |
187 | sctp_sk(asoc->base.sk)->pf->af->net_header_len - | |
188 | sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk); | |
1da177e4 | 189 | |
3e62abf9 | 190 | max = asoc->frag_point; |
4cd57c80 VY |
191 | /* If the the peer requested that we authenticate DATA chunks |
192 | * we need to accound for bundling of the AUTH chunks along with | |
193 | * DATA. | |
194 | */ | |
195 | if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { | |
196 | struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); | |
197 | ||
198 | if (hmac_desc) | |
3e62abf9 | 199 | max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) + |
4cd57c80 VY |
200 | hmac_desc->hmac_len); |
201 | } | |
202 | ||
3e62abf9 VY |
203 | /* Now, check if we need to reduce our max */ |
204 | if (max > max_data) | |
205 | max = max_data; | |
206 | ||
1da177e4 LT |
207 | whole = 0; |
208 | first_len = max; | |
209 | ||
5d7ff261 VY |
210 | /* Check to see if we have a pending SACK and try to let it be bundled |
211 | * with this message. Do this if we don't have any data queued already. | |
212 | * To check that, look at out_qlen and retransmit list. | |
213 | * NOTE: we will not reduce to account for SACK, if the message would | |
214 | * not have been fragmented. | |
215 | */ | |
216 | if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) && | |
217 | asoc->outqueue.out_qlen == 0 && | |
218 | list_empty(&asoc->outqueue.retransmit) && | |
219 | msg_len > max) | |
220 | max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t)); | |
221 | ||
1da177e4 | 222 | /* Encourage Cookie-ECHO bundling. */ |
5d7ff261 | 223 | if (asoc->state < SCTP_STATE_COOKIE_ECHOED) |
3e62abf9 | 224 | max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; |
1da177e4 | 225 | |
5d7ff261 VY |
226 | /* Now that we adjusted completely, reset first_len */ |
227 | if (first_len > max_data) | |
228 | first_len = max_data; | |
3e62abf9 VY |
229 | |
230 | /* Account for a different sized first fragment */ | |
231 | if (msg_len >= first_len) { | |
232 | msg_len -= first_len; | |
233 | whole = 1; | |
1da177e4 LT |
234 | } |
235 | ||
236 | /* How many full sized? How many bytes leftover? */ | |
237 | whole += msg_len / max; | |
238 | over = msg_len % max; | |
239 | offset = 0; | |
240 | ||
241 | if ((whole > 1) || (whole && over)) | |
242 | SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS); | |
243 | ||
244 | /* Create chunks for all the full sized DATA chunks. */ | |
245 | for (i=0, len=first_len; i < whole; i++) { | |
246 | frag = SCTP_DATA_MIDDLE_FRAG; | |
247 | ||
248 | if (0 == i) | |
249 | frag |= SCTP_DATA_FIRST_FRAG; | |
250 | ||
251 | if ((i == (whole - 1)) && !over) | |
252 | frag |= SCTP_DATA_LAST_FRAG; | |
253 | ||
254 | chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0); | |
255 | ||
256 | if (!chunk) | |
257 | goto errout; | |
258 | err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov); | |
259 | if (err < 0) | |
260 | goto errout; | |
261 | ||
262 | offset += len; | |
263 | ||
264 | /* Put the chunk->skb back into the form expected by send. */ | |
265 | __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr | |
266 | - (__u8 *)chunk->skb->data); | |
267 | ||
268 | sctp_datamsg_assign(msg, chunk); | |
269 | list_add_tail(&chunk->frag_list, &msg->chunks); | |
270 | ||
271 | /* The first chunk, the first chunk was likely short | |
272 | * to allow bundling, so reset to full size. | |
273 | */ | |
274 | if (0 == i) | |
275 | len = max; | |
276 | } | |
277 | ||
278 | /* .. now the leftover bytes. */ | |
279 | if (over) { | |
280 | if (!whole) | |
281 | frag = SCTP_DATA_NOT_FRAG; | |
282 | else | |
283 | frag = SCTP_DATA_LAST_FRAG; | |
284 | ||
285 | chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0); | |
286 | ||
287 | if (!chunk) | |
288 | goto errout; | |
289 | ||
290 | err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov); | |
291 | ||
292 | /* Put the chunk->skb back into the form expected by send. */ | |
293 | __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr | |
294 | - (__u8 *)chunk->skb->data); | |
295 | if (err < 0) | |
296 | goto errout; | |
297 | ||
298 | sctp_datamsg_assign(msg, chunk); | |
299 | list_add_tail(&chunk->frag_list, &msg->chunks); | |
300 | } | |
301 | ||
302 | return msg; | |
303 | ||
304 | errout: | |
305 | list_for_each_safe(pos, temp, &msg->chunks) { | |
306 | list_del_init(pos); | |
307 | chunk = list_entry(pos, struct sctp_chunk, frag_list); | |
308 | sctp_chunk_free(chunk); | |
309 | } | |
80445cfb | 310 | sctp_datamsg_put(msg); |
1da177e4 LT |
311 | return NULL; |
312 | } | |
313 | ||
314 | /* Check whether this message has expired. */ | |
315 | int sctp_chunk_abandoned(struct sctp_chunk *chunk) | |
316 | { | |
317 | struct sctp_datamsg *msg = chunk->msg; | |
318 | ||
319 | if (!msg->can_abandon) | |
320 | return 0; | |
321 | ||
322 | if (time_after(jiffies, msg->expires_at)) | |
323 | return 1; | |
324 | ||
325 | return 0; | |
326 | } | |
327 | ||
328 | /* This chunk (and consequently entire message) has failed in its sending. */ | |
329 | void sctp_chunk_fail(struct sctp_chunk *chunk, int error) | |
330 | { | |
331 | chunk->msg->send_failed = 1; | |
332 | chunk->msg->send_error = error; | |
333 | } |