1 /* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2003, 2004
4 * This file is part of the SCTP kernel implementation
6 * This file contains the code relating the chunk abstraction.
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)
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.
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.
25 * Please send any bug reports or fixes you make to the
27 * lksctp developers <lksctp-developers@lists.sourceforge.net>
29 * Or submit a bug report through the following website:
30 * http://www.sf.net/projects/lksctp
32 * Written or modified by:
33 * Jon Grimm <jgrimm@us.ibm.com>
34 * Sridhar Samudrala <sri@us.ibm.com>
36 * Any bugs reported given to us we will try to fix... any fixes shared will
37 * be incorporated into the next SCTP release.
40 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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>
49 #include <net/sctp/sctp.h>
50 #include <net/sctp/sm.h>
52 /* This file is mostly in anticipation of future work, but initially
53 * populate with fragment tracking for an outbound message.
56 /* Initialize datamsg from memory. */
57 static void sctp_datamsg_init(struct sctp_datamsg
*msg
)
59 atomic_set(&msg
->refcnt
, 1);
65 INIT_LIST_HEAD(&msg
->chunks
);
68 /* Allocate and initialize datamsg. */
69 SCTP_STATIC
struct sctp_datamsg
*sctp_datamsg_new(gfp_t gfp
)
71 struct sctp_datamsg
*msg
;
72 msg
= kmalloc(sizeof(struct sctp_datamsg
), gfp
);
74 sctp_datamsg_init(msg
);
75 SCTP_DBG_OBJCNT_INC(datamsg
);
80 void sctp_datamsg_free(struct sctp_datamsg
*msg
)
82 struct sctp_chunk
*chunk
;
84 /* This doesn't have to be a _safe vairant because
85 * sctp_chunk_free() only drops the refs.
87 list_for_each_entry(chunk
, &msg
->chunks
, frag_list
)
88 sctp_chunk_free(chunk
);
90 sctp_datamsg_put(msg
);
93 /* Final destructruction of datamsg memory. */
94 static void sctp_datamsg_destroy(struct sctp_datamsg
*msg
)
96 struct list_head
*pos
, *temp
;
97 struct sctp_chunk
*chunk
;
99 struct sctp_ulpevent
*ev
;
100 struct sctp_association
*asoc
= NULL
;
101 int error
= 0, notify
;
103 /* If we failed, we may need to notify. */
104 notify
= msg
->send_failed
? -1 : 0;
106 /* Release all references. */
107 list_for_each_safe(pos
, temp
, &msg
->chunks
) {
109 chunk
= list_entry(pos
, struct sctp_chunk
, frag_list
);
110 /* Check whether we _really_ need to notify. */
114 error
= msg
->send_error
;
116 error
= asoc
->outqueue
.error
;
118 sp
= sctp_sk(asoc
->base
.sk
);
119 notify
= sctp_ulpevent_type_enabled(SCTP_SEND_FAILED
,
123 /* Generate a SEND FAILED event only if enabled. */
127 sent
= SCTP_DATA_SENT
;
129 sent
= SCTP_DATA_UNSENT
;
131 ev
= sctp_ulpevent_make_send_failed(asoc
, chunk
, sent
,
134 sctp_ulpq_tail_event(&asoc
->ulpq
, ev
);
137 sctp_chunk_put(chunk
);
140 SCTP_DBG_OBJCNT_DEC(datamsg
);
144 /* Hold a reference. */
145 static void sctp_datamsg_hold(struct sctp_datamsg
*msg
)
147 atomic_inc(&msg
->refcnt
);
150 /* Release a reference. */
151 void sctp_datamsg_put(struct sctp_datamsg
*msg
)
153 if (atomic_dec_and_test(&msg
->refcnt
))
154 sctp_datamsg_destroy(msg
);
157 /* Assign a chunk to this datamsg. */
158 static void sctp_datamsg_assign(struct sctp_datamsg
*msg
, struct sctp_chunk
*chunk
)
160 sctp_datamsg_hold(msg
);
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
172 struct sctp_datamsg
*sctp_datamsg_from_user(struct sctp_association
*asoc
,
173 struct sctp_sndrcvinfo
*sinfo
,
174 struct msghdr
*msgh
, int msg_len
)
176 int max
, whole
, i
, offset
, over
, err
;
179 struct sctp_chunk
*chunk
;
180 struct sctp_datamsg
*msg
;
181 struct list_head
*pos
, *temp
;
184 msg
= sctp_datamsg_new(GFP_KERNEL
);
186 return ERR_PTR(-ENOMEM
);
188 /* Note: Calculate this outside of the loop, so that all fragments
189 * have the same expiration.
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
);
200 /* This is the biggest possible DATA chunk that can fit into
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
);
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
212 if (sctp_auth_send_cid(SCTP_CID_DATA
, asoc
)) {
213 struct sctp_hmac
*hmac_desc
= sctp_auth_asoc_get_hmac(asoc
);
216 max_data
-= WORD_ROUND(sizeof(sctp_auth_chunk_t
) +
217 hmac_desc
->hmac_len
);
220 /* Now, check if we need to reduce our max */
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.
233 if (timer_pending(&asoc
->timers
[SCTP_EVENT_TIMEOUT_SACK
]) &&
234 asoc
->outqueue
.out_qlen
== 0 &&
235 list_empty(&asoc
->outqueue
.retransmit
) &&
237 max_data
-= WORD_ROUND(sizeof(sctp_sack_chunk_t
));
239 /* Encourage Cookie-ECHO bundling. */
240 if (asoc
->state
< SCTP_STATE_COOKIE_ECHOED
)
241 max_data
-= SCTP_ARBITRARY_COOKIE_ECHO_LEN
;
243 /* Now that we adjusted completely, reset first_len */
244 if (first_len
> max_data
)
245 first_len
= max_data
;
247 /* Account for a different sized first fragment */
248 if (msg_len
>= first_len
) {
249 msg_len
-= first_len
;
254 /* How many full sized? How many bytes leftover? */
255 whole
+= msg_len
/ max
;
256 over
= msg_len
% max
;
259 if ((whole
> 1) || (whole
&& over
))
260 SCTP_INC_STATS_USER(sock_net(asoc
->base
.sk
), SCTP_MIB_FRAGUSRMSGS
);
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
;
267 frag
|= SCTP_DATA_FIRST_FRAG
;
269 if ((i
== (whole
- 1)) && !over
) {
270 frag
|= SCTP_DATA_LAST_FRAG
;
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.
276 if ((sinfo
->sinfo_flags
& SCTP_EOF
) ||
277 (sinfo
->sinfo_flags
& SCTP_SACK_IMMEDIATELY
))
278 frag
|= SCTP_DATA_SACK_IMM
;
281 chunk
= sctp_make_datafrag_empty(asoc
, sinfo
, len
, frag
, 0);
288 err
= sctp_user_addto_chunk(chunk
, offset
, len
, msgh
->msg_iov
);
290 goto errout_chunk_free
;
294 /* Put the chunk->skb back into the form expected by send. */
295 __skb_pull(chunk
->skb
, (__u8
*)chunk
->chunk_hdr
296 - (__u8
*)chunk
->skb
->data
);
298 sctp_datamsg_assign(msg
, chunk
);
299 list_add_tail(&chunk
->frag_list
, &msg
->chunks
);
301 /* The first chunk, the first chunk was likely short
302 * to allow bundling, so reset to full size.
308 /* .. now the leftover bytes. */
311 frag
= SCTP_DATA_NOT_FRAG
;
313 frag
= SCTP_DATA_LAST_FRAG
;
315 if ((sinfo
->sinfo_flags
& SCTP_EOF
) ||
316 (sinfo
->sinfo_flags
& SCTP_SACK_IMMEDIATELY
))
317 frag
|= SCTP_DATA_SACK_IMM
;
319 chunk
= sctp_make_datafrag_empty(asoc
, sinfo
, over
, frag
, 0);
326 err
= sctp_user_addto_chunk(chunk
, offset
, over
,msgh
->msg_iov
);
328 /* Put the chunk->skb back into the form expected by send. */
329 __skb_pull(chunk
->skb
, (__u8
*)chunk
->chunk_hdr
330 - (__u8
*)chunk
->skb
->data
);
332 goto errout_chunk_free
;
334 sctp_datamsg_assign(msg
, chunk
);
335 list_add_tail(&chunk
->frag_list
, &msg
->chunks
);
341 sctp_chunk_free(chunk
);
344 list_for_each_safe(pos
, temp
, &msg
->chunks
) {
346 chunk
= list_entry(pos
, struct sctp_chunk
, frag_list
);
347 sctp_chunk_free(chunk
);
349 sctp_datamsg_put(msg
);
353 /* Check whether this message has expired. */
354 int sctp_chunk_abandoned(struct sctp_chunk
*chunk
)
356 struct sctp_datamsg
*msg
= chunk
->msg
;
358 if (!msg
->can_abandon
)
361 if (time_after(jiffies
, msg
->expires_at
))
367 /* This chunk (and consequently entire message) has failed in its sending. */
368 void sctp_chunk_fail(struct sctp_chunk
*chunk
, int error
)
370 chunk
->msg
->send_failed
= 1;
371 chunk
->msg
->send_error
= error
;