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1 | /* SCTP kernel implementation | |
2 | * (C) Copyright IBM Corp. 2003, 2004 | |
3 | * | |
4 | * This file is part of the SCTP kernel implementation | |
5 | * | |
6 | * This file contains the code relating the chunk abstraction. | |
7 | * | |
8 | * This SCTP 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 | * This SCTP 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. */ | |
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 | msg->msg_size = 0; | |
63 | } | |
64 | ||
65 | /* Allocate and initialize datamsg. */ | |
66 | SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) | |
67 | { | |
68 | struct sctp_datamsg *msg; | |
69 | msg = kmalloc(sizeof(struct sctp_datamsg), gfp); | |
70 | if (msg) { | |
71 | sctp_datamsg_init(msg); | |
72 | SCTP_DBG_OBJCNT_INC(datamsg); | |
73 | } | |
74 | return msg; | |
75 | } | |
76 | ||
77 | void 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 | ||
90 | /* Final destructruction of datamsg memory. */ | |
91 | static 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. */ | |
142 | static void sctp_datamsg_hold(struct sctp_datamsg *msg) | |
143 | { | |
144 | atomic_inc(&msg->refcnt); | |
145 | } | |
146 | ||
147 | /* Release a reference. */ | |
148 | void sctp_datamsg_put(struct sctp_datamsg *msg) | |
149 | { | |
150 | if (atomic_dec_and_test(&msg->refcnt)) | |
151 | sctp_datamsg_destroy(msg); | |
152 | } | |
153 | ||
154 | /* Assign a chunk to this datamsg. */ | |
155 | static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) | |
156 | { | |
157 | sctp_datamsg_hold(msg); | |
158 | chunk->msg = msg; | |
159 | msg->msg_size += chunk->skb->len; | |
160 | } | |
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 | */ | |
170 | struct 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; | |
176 | int max_data; | |
177 | 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", | |
195 | __func__, msg, msg->expires_at, jiffies); | |
196 | } | |
197 | ||
198 | /* 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); | |
204 | ||
205 | max = asoc->frag_point; | |
206 | /* 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) | |
214 | max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) + | |
215 | hmac_desc->hmac_len); | |
216 | } | |
217 | ||
218 | /* Now, check if we need to reduce our max */ | |
219 | if (max > max_data) | |
220 | max = max_data; | |
221 | ||
222 | whole = 0; | |
223 | first_len = max; | |
224 | ||
225 | /* 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 | ||
237 | /* Encourage Cookie-ECHO bundling. */ | |
238 | if (asoc->state < SCTP_STATE_COOKIE_ECHOED) | |
239 | max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; | |
240 | ||
241 | /* Now that we adjusted completely, reset first_len */ | |
242 | if (first_len > max_data) | |
243 | first_len = max_data; | |
244 | ||
245 | /* Account for a different sized first fragment */ | |
246 | if (msg_len >= first_len) { | |
247 | msg_len -= first_len; | |
248 | whole = 1; | |
249 | } | |
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 | /* The application requests to set the I-bit of the | |
270 | * last DATA chunk of a user message when providing | |
271 | * the user message to the SCTP implementation. | |
272 | */ | |
273 | if ((sinfo->sinfo_flags & SCTP_EOF) || | |
274 | (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) | |
275 | frag |= SCTP_DATA_SACK_IMM; | |
276 | } | |
277 | ||
278 | chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0); | |
279 | ||
280 | if (!chunk) | |
281 | goto errout; | |
282 | err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov); | |
283 | if (err < 0) | |
284 | goto errout; | |
285 | ||
286 | offset += len; | |
287 | ||
288 | /* Put the chunk->skb back into the form expected by send. */ | |
289 | __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr | |
290 | - (__u8 *)chunk->skb->data); | |
291 | ||
292 | sctp_datamsg_assign(msg, chunk); | |
293 | list_add_tail(&chunk->frag_list, &msg->chunks); | |
294 | ||
295 | /* The first chunk, the first chunk was likely short | |
296 | * to allow bundling, so reset to full size. | |
297 | */ | |
298 | if (0 == i) | |
299 | len = max; | |
300 | } | |
301 | ||
302 | /* .. now the leftover bytes. */ | |
303 | if (over) { | |
304 | if (!whole) | |
305 | frag = SCTP_DATA_NOT_FRAG; | |
306 | else | |
307 | frag = SCTP_DATA_LAST_FRAG; | |
308 | ||
309 | if ((sinfo->sinfo_flags & SCTP_EOF) || | |
310 | (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) | |
311 | frag |= SCTP_DATA_SACK_IMM; | |
312 | ||
313 | chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0); | |
314 | ||
315 | if (!chunk) | |
316 | goto errout; | |
317 | ||
318 | err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov); | |
319 | ||
320 | /* Put the chunk->skb back into the form expected by send. */ | |
321 | __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr | |
322 | - (__u8 *)chunk->skb->data); | |
323 | if (err < 0) | |
324 | goto errout; | |
325 | ||
326 | sctp_datamsg_assign(msg, chunk); | |
327 | list_add_tail(&chunk->frag_list, &msg->chunks); | |
328 | } | |
329 | ||
330 | return msg; | |
331 | ||
332 | errout: | |
333 | list_for_each_safe(pos, temp, &msg->chunks) { | |
334 | list_del_init(pos); | |
335 | chunk = list_entry(pos, struct sctp_chunk, frag_list); | |
336 | sctp_chunk_free(chunk); | |
337 | } | |
338 | sctp_datamsg_put(msg); | |
339 | return NULL; | |
340 | } | |
341 | ||
342 | /* Check whether this message has expired. */ | |
343 | int sctp_chunk_abandoned(struct sctp_chunk *chunk) | |
344 | { | |
345 | struct sctp_datamsg *msg = chunk->msg; | |
346 | ||
347 | if (!msg->can_abandon) | |
348 | return 0; | |
349 | ||
350 | if (time_after(jiffies, msg->expires_at)) | |
351 | return 1; | |
352 | ||
353 | return 0; | |
354 | } | |
355 | ||
356 | /* This chunk (and consequently entire message) has failed in its sending. */ | |
357 | void sctp_chunk_fail(struct sctp_chunk *chunk, int error) | |
358 | { | |
359 | chunk->msg->send_failed = 1; | |
360 | chunk->msg->send_error = error; | |
361 | } |