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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 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
41 | |
42 | #include <linux/types.h> |
43 | #include <linux/kernel.h> |
44 | #include <linux/net.h> |
45 | #include <linux/inet.h> |
46 | #include <linux/skbuff.h> |
47 | #include <linux/slab.h> |
48 | #include <net/sock.h> |
49 | #include <net/sctp/sctp.h> |
50 | #include <net/sctp/sm.h> |
51 | |
52 | /* This file is mostly in anticipation of future work, but initially |
53 | * populate with fragment tracking for an outbound message. |
54 | */ |
55 | |
56 | /* Initialize datamsg from memory. */ |
57 | static void sctp_datamsg_init(struct sctp_datamsg *msg) |
58 | { |
59 | atomic_set(&msg->refcnt, 1); |
60 | msg->send_failed = 0; |
61 | msg->send_error = 0; |
62 | msg->can_abandon = 0; |
63 | msg->can_delay = 1; |
64 | msg->expires_at = 0; |
65 | INIT_LIST_HEAD(&msg->chunks); |
66 | } |
67 | |
68 | /* Allocate and initialize datamsg. */ |
69 | SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp) |
70 | { |
71 | struct sctp_datamsg *msg; |
72 | msg = kmalloc(sizeof(struct sctp_datamsg), gfp); |
73 | if (msg) { |
74 | sctp_datamsg_init(msg); |
75 | SCTP_DBG_OBJCNT_INC(datamsg); |
76 | } |
77 | return msg; |
78 | } |
79 | |
80 | void sctp_datamsg_free(struct sctp_datamsg *msg) |
81 | { |
82 | struct sctp_chunk *chunk; |
83 | |
84 | /* This doesn't have to be a _safe vairant because |
85 | * sctp_chunk_free() only drops the refs. |
86 | */ |
87 | list_for_each_entry(chunk, &msg->chunks, frag_list) |
88 | sctp_chunk_free(chunk); |
89 | |
90 | sctp_datamsg_put(msg); |
91 | } |
92 | |
93 | /* Final destructruction of datamsg memory. */ |
94 | static void sctp_datamsg_destroy(struct sctp_datamsg *msg) |
95 | { |
96 | struct list_head *pos, *temp; |
97 | struct sctp_chunk *chunk; |
98 | struct sctp_sock *sp; |
99 | struct sctp_ulpevent *ev; |
100 | struct sctp_association *asoc = NULL; |
101 | int error = 0, notify; |
102 | |
103 | /* If we failed, we may need to notify. */ |
104 | notify = msg->send_failed ? -1 : 0; |
105 | |
106 | /* Release all references. */ |
107 | list_for_each_safe(pos, temp, &msg->chunks) { |
108 | list_del_init(pos); |
109 | chunk = list_entry(pos, struct sctp_chunk, frag_list); |
110 | /* Check whether we _really_ need to notify. */ |
111 | if (notify < 0) { |
112 | asoc = chunk->asoc; |
113 | if (msg->send_error) |
114 | error = msg->send_error; |
115 | else |
116 | error = asoc->outqueue.error; |
117 | |
118 | sp = sctp_sk(asoc->base.sk); |
119 | notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED, |
120 | &sp->subscribe); |
121 | } |
122 | |
123 | /* Generate a SEND FAILED event only if enabled. */ |
124 | if (notify > 0) { |
125 | int sent; |
126 | if (chunk->has_tsn) |
127 | sent = SCTP_DATA_SENT; |
128 | else |
129 | sent = SCTP_DATA_UNSENT; |
130 | |
131 | ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent, |
132 | error, GFP_ATOMIC); |
133 | if (ev) |
134 | sctp_ulpq_tail_event(&asoc->ulpq, ev); |
135 | } |
136 | |
137 | sctp_chunk_put(chunk); |
138 | } |
139 | |
140 | SCTP_DBG_OBJCNT_DEC(datamsg); |
141 | kfree(msg); |
142 | } |
143 | |
144 | /* Hold a reference. */ |
145 | static void sctp_datamsg_hold(struct sctp_datamsg *msg) |
146 | { |
147 | atomic_inc(&msg->refcnt); |
148 | } |
149 | |
150 | /* Release a reference. */ |
151 | void sctp_datamsg_put(struct sctp_datamsg *msg) |
152 | { |
153 | if (atomic_dec_and_test(&msg->refcnt)) |
154 | sctp_datamsg_destroy(msg); |
155 | } |
156 | |
157 | /* Assign a chunk to this datamsg. */ |
158 | static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk) |
159 | { |
160 | sctp_datamsg_hold(msg); |
161 | chunk->msg = msg; |
162 | } |
163 | |
164 | |
165 | /* A data chunk can have a maximum payload of (2^16 - 20). Break |
166 | * down any such message into smaller chunks. Opportunistically, fragment |
167 | * the chunks down to the current MTU constraints. We may get refragmented |
168 | * later if the PMTU changes, but it is _much better_ to fragment immediately |
169 | * with a reasonable guess than always doing our fragmentation on the |
170 | * soft-interrupt. |
171 | */ |
172 | struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc, |
173 | struct sctp_sndrcvinfo *sinfo, |
174 | struct msghdr *msgh, int msg_len) |
175 | { |
176 | int max, whole, i, offset, over, err; |
177 | int len, first_len; |
178 | int max_data; |
179 | struct sctp_chunk *chunk; |
180 | struct sctp_datamsg *msg; |
181 | struct list_head *pos, *temp; |
182 | __u8 frag; |
183 | |
184 | msg = sctp_datamsg_new(GFP_KERNEL); |
185 | if (!msg) |
186 | return NULL; |
187 | |
188 | /* Note: Calculate this outside of the loop, so that all fragments |
189 | * have the same expiration. |
190 | */ |
191 | if (sinfo->sinfo_timetolive) { |
192 | /* sinfo_timetolive is in milliseconds */ |
193 | msg->expires_at = jiffies + |
194 | msecs_to_jiffies(sinfo->sinfo_timetolive); |
195 | msg->can_abandon = 1; |
196 | SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n", |
197 | __func__, msg, msg->expires_at, jiffies); |
198 | } |
199 | |
200 | /* This is the biggest possible DATA chunk that can fit into |
201 | * the packet |
202 | */ |
203 | max_data = asoc->pathmtu - |
204 | sctp_sk(asoc->base.sk)->pf->af->net_header_len - |
205 | sizeof(struct sctphdr) - sizeof(struct sctp_data_chunk); |
206 | |
207 | max = asoc->frag_point; |
208 | /* If the the peer requested that we authenticate DATA chunks |
209 | * we need to accound for bundling of the AUTH chunks along with |
210 | * DATA. |
211 | */ |
212 | if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) { |
213 | struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc); |
214 | |
215 | if (hmac_desc) |
216 | max_data -= WORD_ROUND(sizeof(sctp_auth_chunk_t) + |
217 | hmac_desc->hmac_len); |
218 | } |
219 | |
220 | /* Now, check if we need to reduce our max */ |
221 | if (max > max_data) |
222 | max = max_data; |
223 | |
224 | whole = 0; |
225 | first_len = max; |
226 | |
227 | /* Check to see if we have a pending SACK and try to let it be bundled |
228 | * with this message. Do this if we don't have any data queued already. |
229 | * To check that, look at out_qlen and retransmit list. |
230 | * NOTE: we will not reduce to account for SACK, if the message would |
231 | * not have been fragmented. |
232 | */ |
233 | if (timer_pending(&asoc->timers[SCTP_EVENT_TIMEOUT_SACK]) && |
234 | asoc->outqueue.out_qlen == 0 && |
235 | list_empty(&asoc->outqueue.retransmit) && |
236 | msg_len > max) |
237 | max_data -= WORD_ROUND(sizeof(sctp_sack_chunk_t)); |
238 | |
239 | /* Encourage Cookie-ECHO bundling. */ |
240 | if (asoc->state < SCTP_STATE_COOKIE_ECHOED) |
241 | max_data -= SCTP_ARBITRARY_COOKIE_ECHO_LEN; |
242 | |
243 | /* Now that we adjusted completely, reset first_len */ |
244 | if (first_len > max_data) |
245 | first_len = max_data; |
246 | |
247 | /* Account for a different sized first fragment */ |
248 | if (msg_len >= first_len) { |
249 | msg_len -= first_len; |
250 | whole = 1; |
251 | msg->can_delay = 0; |
252 | } |
253 | |
254 | /* How many full sized? How many bytes leftover? */ |
255 | whole += msg_len / max; |
256 | over = msg_len % max; |
257 | offset = 0; |
258 | |
259 | if ((whole > 1) || (whole && over)) |
260 | SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS); |
261 | |
262 | /* Create chunks for all the full sized DATA chunks. */ |
263 | for (i=0, len=first_len; i < whole; i++) { |
264 | frag = SCTP_DATA_MIDDLE_FRAG; |
265 | |
266 | if (0 == i) |
267 | frag |= SCTP_DATA_FIRST_FRAG; |
268 | |
269 | if ((i == (whole - 1)) && !over) { |
270 | frag |= SCTP_DATA_LAST_FRAG; |
271 | |
272 | /* The application requests to set the I-bit of the |
273 | * last DATA chunk of a user message when providing |
274 | * the user message to the SCTP implementation. |
275 | */ |
276 | if ((sinfo->sinfo_flags & SCTP_EOF) || |
277 | (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) |
278 | frag |= SCTP_DATA_SACK_IMM; |
279 | } |
280 | |
281 | chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0); |
282 | |
283 | if (!chunk) |
284 | goto errout; |
285 | err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov); |
286 | if (err < 0) |
287 | goto errout; |
288 | |
289 | offset += len; |
290 | |
291 | /* Put the chunk->skb back into the form expected by send. */ |
292 | __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr |
293 | - (__u8 *)chunk->skb->data); |
294 | |
295 | sctp_datamsg_assign(msg, chunk); |
296 | list_add_tail(&chunk->frag_list, &msg->chunks); |
297 | |
298 | /* The first chunk, the first chunk was likely short |
299 | * to allow bundling, so reset to full size. |
300 | */ |
301 | if (0 == i) |
302 | len = max; |
303 | } |
304 | |
305 | /* .. now the leftover bytes. */ |
306 | if (over) { |
307 | if (!whole) |
308 | frag = SCTP_DATA_NOT_FRAG; |
309 | else |
310 | frag = SCTP_DATA_LAST_FRAG; |
311 | |
312 | if ((sinfo->sinfo_flags & SCTP_EOF) || |
313 | (sinfo->sinfo_flags & SCTP_SACK_IMMEDIATELY)) |
314 | frag |= SCTP_DATA_SACK_IMM; |
315 | |
316 | chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0); |
317 | |
318 | if (!chunk) |
319 | goto errout; |
320 | |
321 | err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov); |
322 | |
323 | /* Put the chunk->skb back into the form expected by send. */ |
324 | __skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr |
325 | - (__u8 *)chunk->skb->data); |
326 | if (err < 0) |
327 | goto errout; |
328 | |
329 | sctp_datamsg_assign(msg, chunk); |
330 | list_add_tail(&chunk->frag_list, &msg->chunks); |
331 | } |
332 | |
333 | return msg; |
334 | |
335 | errout: |
336 | list_for_each_safe(pos, temp, &msg->chunks) { |
337 | list_del_init(pos); |
338 | chunk = list_entry(pos, struct sctp_chunk, frag_list); |
339 | sctp_chunk_free(chunk); |
340 | } |
341 | sctp_datamsg_put(msg); |
342 | return NULL; |
343 | } |
344 | |
345 | /* Check whether this message has expired. */ |
346 | int sctp_chunk_abandoned(struct sctp_chunk *chunk) |
347 | { |
348 | struct sctp_datamsg *msg = chunk->msg; |
349 | |
350 | if (!msg->can_abandon) |
351 | return 0; |
352 | |
353 | if (time_after(jiffies, msg->expires_at)) |
354 | return 1; |
355 | |
356 | return 0; |
357 | } |
358 | |
359 | /* This chunk (and consequently entire message) has failed in its sending. */ |
360 | void sctp_chunk_fail(struct sctp_chunk *chunk, int error) |
361 | { |
362 | chunk->msg->send_failed = 1; |
363 | chunk->msg->send_error = error; |
364 | } |
365 |
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