1 /* SCTP kernel implementation
2  * (C) Copyright IBM Corp. 2001, 2004
3  * Copyright (c) 1999-2000 Cisco, Inc.
4  * Copyright (c) 1999-2001 Motorola, Inc.
5  * Copyright (c) 2001 Intel Corp.
6  * Copyright (c) 2001 Nokia, Inc.
7  * Copyright (c) 2001 La Monte H.P. Yarroll
8  *
9  * These functions manipulate an sctp event.   The struct ulpevent is used
10  * to carry notifications and data to the ULP (sockets).
11  *
12  * This SCTP implementation is free software;
13  * you can redistribute it and/or modify it under the terms of
14  * the GNU General Public License as published by
15  * the Free Software Foundation; either version 2, or (at your option)
16  * any later version.
17  *
18  * This SCTP implementation is distributed in the hope that it
19  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20  *                 ************************
21  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22  * See the GNU General Public License for more details.
23  *
24  * You should have received a copy of the GNU General Public License
25  * along with GNU CC; see the file COPYING.  If not, write to
26  * the Free Software Foundation, 59 Temple Place - Suite 330,
27  * Boston, MA 02111-1307, USA.
28  *
29  * Please send any bug reports or fixes you make to the
30  * email address(es):
31  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
32  *
33  * Or submit a bug report through the following website:
34  *    http://www.sf.net/projects/lksctp
35  *
36  * Written or modified by:
37  *    Jon Grimm             <jgrimm@us.ibm.com>
38  *    La Monte H.P. Yarroll <piggy@acm.org>
39  *    Ardelle Fan	    <ardelle.fan@intel.com>
40  *    Sridhar Samudrala     <sri@us.ibm.com>
41  *
42  * Any bugs reported given to us we will try to fix... any fixes shared will
43  * be incorporated into the next SCTP release.
44  */
45 
46 #include <linux/slab.h>
47 #include <linux/types.h>
48 #include <linux/skbuff.h>
49 #include <net/sctp/structs.h>
50 #include <net/sctp/sctp.h>
51 #include <net/sctp/sm.h>
52 
53 static void sctp_ulpevent_receive_data(struct sctp_ulpevent *event,
54 				       struct sctp_association *asoc);
55 static void sctp_ulpevent_release_data(struct sctp_ulpevent *event);
56 static void sctp_ulpevent_release_frag_data(struct sctp_ulpevent *event);
57 
58 
59 /* Initialize an ULP event from an given skb.  */
sctp_ulpevent_init(struct sctp_ulpevent * event,int msg_flags,unsigned int len)60 SCTP_STATIC void sctp_ulpevent_init(struct sctp_ulpevent *event,
61 				    int msg_flags,
62 				    unsigned int len)
63 {
64 	memset(event, 0, sizeof(struct sctp_ulpevent));
65 	event->msg_flags = msg_flags;
66 	event->rmem_len = len;
67 }
68 
69 /* Create a new sctp_ulpevent.  */
sctp_ulpevent_new(int size,int msg_flags,gfp_t gfp)70 SCTP_STATIC struct sctp_ulpevent *sctp_ulpevent_new(int size, int msg_flags,
71 						    gfp_t gfp)
72 {
73 	struct sctp_ulpevent *event;
74 	struct sk_buff *skb;
75 
76 	skb = alloc_skb(size, gfp);
77 	if (!skb)
78 		goto fail;
79 
80 	event = sctp_skb2event(skb);
81 	sctp_ulpevent_init(event, msg_flags, skb->truesize);
82 
83 	return event;
84 
85 fail:
86 	return NULL;
87 }
88 
89 /* Is this a MSG_NOTIFICATION?  */
sctp_ulpevent_is_notification(const struct sctp_ulpevent * event)90 int sctp_ulpevent_is_notification(const struct sctp_ulpevent *event)
91 {
92 	return MSG_NOTIFICATION == (event->msg_flags & MSG_NOTIFICATION);
93 }
94 
95 /* Hold the association in case the msg_name needs read out of
96  * the association.
97  */
sctp_ulpevent_set_owner(struct sctp_ulpevent * event,const struct sctp_association * asoc)98 static inline void sctp_ulpevent_set_owner(struct sctp_ulpevent *event,
99 					   const struct sctp_association *asoc)
100 {
101 	struct sk_buff *skb;
102 
103 	/* Cast away the const, as we are just wanting to
104 	 * bump the reference count.
105 	 */
106 	sctp_association_hold((struct sctp_association *)asoc);
107 	skb = sctp_event2skb(event);
108 	event->asoc = (struct sctp_association *)asoc;
109 	atomic_add(event->rmem_len, &event->asoc->rmem_alloc);
110 	sctp_skb_set_owner_r(skb, asoc->base.sk);
111 }
112 
113 /* A simple destructor to give up the reference to the association. */
sctp_ulpevent_release_owner(struct sctp_ulpevent * event)114 static inline void sctp_ulpevent_release_owner(struct sctp_ulpevent *event)
115 {
116 	struct sctp_association *asoc = event->asoc;
117 
118 	atomic_sub(event->rmem_len, &asoc->rmem_alloc);
119 	sctp_association_put(asoc);
120 }
121 
122 /* Create and initialize an SCTP_ASSOC_CHANGE event.
123  *
124  * 5.3.1.1 SCTP_ASSOC_CHANGE
125  *
126  * Communication notifications inform the ULP that an SCTP association
127  * has either begun or ended. The identifier for a new association is
128  * provided by this notification.
129  *
130  * Note: There is no field checking here.  If a field is unused it will be
131  * zero'd out.
132  */
sctp_ulpevent_make_assoc_change(const struct sctp_association * asoc,__u16 flags,__u16 state,__u16 error,__u16 outbound,__u16 inbound,struct sctp_chunk * chunk,gfp_t gfp)133 struct sctp_ulpevent  *sctp_ulpevent_make_assoc_change(
134 	const struct sctp_association *asoc,
135 	__u16 flags, __u16 state, __u16 error, __u16 outbound,
136 	__u16 inbound, struct sctp_chunk *chunk, gfp_t gfp)
137 {
138 	struct sctp_ulpevent *event;
139 	struct sctp_assoc_change *sac;
140 	struct sk_buff *skb;
141 
142 	/* If the lower layer passed in the chunk, it will be
143 	 * an ABORT, so we need to include it in the sac_info.
144 	 */
145 	if (chunk) {
146 		/* Copy the chunk data to a new skb and reserve enough
147 		 * head room to use as notification.
148 		 */
149 		skb = skb_copy_expand(chunk->skb,
150 				      sizeof(struct sctp_assoc_change), 0, gfp);
151 
152 		if (!skb)
153 			goto fail;
154 
155 		/* Embed the event fields inside the cloned skb.  */
156 		event = sctp_skb2event(skb);
157 		sctp_ulpevent_init(event, MSG_NOTIFICATION, skb->truesize);
158 
159 		/* Include the notification structure */
160 		sac = (struct sctp_assoc_change *)
161 			skb_push(skb, sizeof(struct sctp_assoc_change));
162 
163 		/* Trim the buffer to the right length.  */
164 		skb_trim(skb, sizeof(struct sctp_assoc_change) +
165 			 ntohs(chunk->chunk_hdr->length) -
166 			 sizeof(sctp_chunkhdr_t));
167 	} else {
168 		event = sctp_ulpevent_new(sizeof(struct sctp_assoc_change),
169 				  MSG_NOTIFICATION, gfp);
170 		if (!event)
171 			goto fail;
172 
173 		skb = sctp_event2skb(event);
174 		sac = (struct sctp_assoc_change *) skb_put(skb,
175 					sizeof(struct sctp_assoc_change));
176 	}
177 
178 	/* Socket Extensions for SCTP
179 	 * 5.3.1.1 SCTP_ASSOC_CHANGE
180 	 *
181 	 * sac_type:
182 	 * It should be SCTP_ASSOC_CHANGE.
183 	 */
184 	sac->sac_type = SCTP_ASSOC_CHANGE;
185 
186 	/* Socket Extensions for SCTP
187 	 * 5.3.1.1 SCTP_ASSOC_CHANGE
188 	 *
189 	 * sac_state: 32 bits (signed integer)
190 	 * This field holds one of a number of values that communicate the
191 	 * event that happened to the association.
192 	 */
193 	sac->sac_state = state;
194 
195 	/* Socket Extensions for SCTP
196 	 * 5.3.1.1 SCTP_ASSOC_CHANGE
197 	 *
198 	 * sac_flags: 16 bits (unsigned integer)
199 	 * Currently unused.
200 	 */
201 	sac->sac_flags = 0;
202 
203 	/* Socket Extensions for SCTP
204 	 * 5.3.1.1 SCTP_ASSOC_CHANGE
205 	 *
206 	 * sac_length: sizeof (__u32)
207 	 * This field is the total length of the notification data, including
208 	 * the notification header.
209 	 */
210 	sac->sac_length = skb->len;
211 
212 	/* Socket Extensions for SCTP
213 	 * 5.3.1.1 SCTP_ASSOC_CHANGE
214 	 *
215 	 * sac_error:  32 bits (signed integer)
216 	 *
217 	 * If the state was reached due to a error condition (e.g.
218 	 * COMMUNICATION_LOST) any relevant error information is available in
219 	 * this field. This corresponds to the protocol error codes defined in
220 	 * [SCTP].
221 	 */
222 	sac->sac_error = error;
223 
224 	/* Socket Extensions for SCTP
225 	 * 5.3.1.1 SCTP_ASSOC_CHANGE
226 	 *
227 	 * sac_outbound_streams:  16 bits (unsigned integer)
228 	 * sac_inbound_streams:  16 bits (unsigned integer)
229 	 *
230 	 * The maximum number of streams allowed in each direction are
231 	 * available in sac_outbound_streams and sac_inbound streams.
232 	 */
233 	sac->sac_outbound_streams = outbound;
234 	sac->sac_inbound_streams = inbound;
235 
236 	/* Socket Extensions for SCTP
237 	 * 5.3.1.1 SCTP_ASSOC_CHANGE
238 	 *
239 	 * sac_assoc_id: sizeof (sctp_assoc_t)
240 	 *
241 	 * The association id field, holds the identifier for the association.
242 	 * All notifications for a given association have the same association
243 	 * identifier.  For TCP style socket, this field is ignored.
244 	 */
245 	sctp_ulpevent_set_owner(event, asoc);
246 	sac->sac_assoc_id = sctp_assoc2id(asoc);
247 
248 	return event;
249 
250 fail:
251 	return NULL;
252 }
253 
254 /* Create and initialize an SCTP_PEER_ADDR_CHANGE event.
255  *
256  * Socket Extensions for SCTP - draft-01
257  * 5.3.1.2 SCTP_PEER_ADDR_CHANGE
258  *
259  * When a destination address on a multi-homed peer encounters a change
260  * an interface details event is sent.
261  */
sctp_ulpevent_make_peer_addr_change(const struct sctp_association * asoc,const struct sockaddr_storage * aaddr,int flags,int state,int error,gfp_t gfp)262 struct sctp_ulpevent *sctp_ulpevent_make_peer_addr_change(
263 	const struct sctp_association *asoc,
264 	const struct sockaddr_storage *aaddr,
265 	int flags, int state, int error, gfp_t gfp)
266 {
267 	struct sctp_ulpevent *event;
268 	struct sctp_paddr_change  *spc;
269 	struct sk_buff *skb;
270 
271 	event = sctp_ulpevent_new(sizeof(struct sctp_paddr_change),
272 				  MSG_NOTIFICATION, gfp);
273 	if (!event)
274 		goto fail;
275 
276 	skb = sctp_event2skb(event);
277 	spc = (struct sctp_paddr_change *)
278 		skb_put(skb, sizeof(struct sctp_paddr_change));
279 
280 	/* Sockets API Extensions for SCTP
281 	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
282 	 *
283 	 * spc_type:
284 	 *
285 	 *    It should be SCTP_PEER_ADDR_CHANGE.
286 	 */
287 	spc->spc_type = SCTP_PEER_ADDR_CHANGE;
288 
289 	/* Sockets API Extensions for SCTP
290 	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
291 	 *
292 	 * spc_length: sizeof (__u32)
293 	 *
294 	 * This field is the total length of the notification data, including
295 	 * the notification header.
296 	 */
297 	spc->spc_length = sizeof(struct sctp_paddr_change);
298 
299 	/* Sockets API Extensions for SCTP
300 	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
301 	 *
302 	 * spc_flags: 16 bits (unsigned integer)
303 	 * Currently unused.
304 	 */
305 	spc->spc_flags = 0;
306 
307 	/* Sockets API Extensions for SCTP
308 	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
309 	 *
310 	 * spc_state:  32 bits (signed integer)
311 	 *
312 	 * This field holds one of a number of values that communicate the
313 	 * event that happened to the address.
314 	 */
315 	spc->spc_state = state;
316 
317 	/* Sockets API Extensions for SCTP
318 	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
319 	 *
320 	 * spc_error:  32 bits (signed integer)
321 	 *
322 	 * If the state was reached due to any error condition (e.g.
323 	 * ADDRESS_UNREACHABLE) any relevant error information is available in
324 	 * this field.
325 	 */
326 	spc->spc_error = error;
327 
328 	/* Socket Extensions for SCTP
329 	 * 5.3.1.1 SCTP_ASSOC_CHANGE
330 	 *
331 	 * spc_assoc_id: sizeof (sctp_assoc_t)
332 	 *
333 	 * The association id field, holds the identifier for the association.
334 	 * All notifications for a given association have the same association
335 	 * identifier.  For TCP style socket, this field is ignored.
336 	 */
337 	sctp_ulpevent_set_owner(event, asoc);
338 	spc->spc_assoc_id = sctp_assoc2id(asoc);
339 
340 	/* Sockets API Extensions for SCTP
341 	 * Section 5.3.1.2 SCTP_PEER_ADDR_CHANGE
342 	 *
343 	 * spc_aaddr: sizeof (struct sockaddr_storage)
344 	 *
345 	 * The affected address field, holds the remote peer's address that is
346 	 * encountering the change of state.
347 	 */
348 	memcpy(&spc->spc_aaddr, aaddr, sizeof(struct sockaddr_storage));
349 
350 	/* Map ipv4 address into v4-mapped-on-v6 address.  */
351 	sctp_get_pf_specific(asoc->base.sk->sk_family)->addr_v4map(
352 					sctp_sk(asoc->base.sk),
353 					(union sctp_addr *)&spc->spc_aaddr);
354 
355 	return event;
356 
357 fail:
358 	return NULL;
359 }
360 
361 /* Create and initialize an SCTP_REMOTE_ERROR notification.
362  *
363  * Note: This assumes that the chunk->skb->data already points to the
364  * operation error payload.
365  *
366  * Socket Extensions for SCTP - draft-01
367  * 5.3.1.3 SCTP_REMOTE_ERROR
368  *
369  * A remote peer may send an Operational Error message to its peer.
370  * This message indicates a variety of error conditions on an
371  * association. The entire error TLV as it appears on the wire is
372  * included in a SCTP_REMOTE_ERROR event.  Please refer to the SCTP
373  * specification [SCTP] and any extensions for a list of possible
374  * error formats.
375  */
sctp_ulpevent_make_remote_error(const struct sctp_association * asoc,struct sctp_chunk * chunk,__u16 flags,gfp_t gfp)376 struct sctp_ulpevent *sctp_ulpevent_make_remote_error(
377 	const struct sctp_association *asoc, struct sctp_chunk *chunk,
378 	__u16 flags, gfp_t gfp)
379 {
380 	struct sctp_ulpevent *event;
381 	struct sctp_remote_error *sre;
382 	struct sk_buff *skb;
383 	sctp_errhdr_t *ch;
384 	__be16 cause;
385 	int elen;
386 
387 	ch = (sctp_errhdr_t *)(chunk->skb->data);
388 	cause = ch->cause;
389 	elen = WORD_ROUND(ntohs(ch->length)) - sizeof(sctp_errhdr_t);
390 
391 	/* Pull off the ERROR header.  */
392 	skb_pull(chunk->skb, sizeof(sctp_errhdr_t));
393 
394 	/* Copy the skb to a new skb with room for us to prepend
395 	 * notification with.
396 	 */
397 	skb = skb_copy_expand(chunk->skb, sizeof(struct sctp_remote_error),
398 			      0, gfp);
399 
400 	/* Pull off the rest of the cause TLV from the chunk.  */
401 	skb_pull(chunk->skb, elen);
402 	if (!skb)
403 		goto fail;
404 
405 	/* Embed the event fields inside the cloned skb.  */
406 	event = sctp_skb2event(skb);
407 	sctp_ulpevent_init(event, MSG_NOTIFICATION, skb->truesize);
408 
409 	sre = (struct sctp_remote_error *)
410 		skb_push(skb, sizeof(struct sctp_remote_error));
411 
412 	/* Trim the buffer to the right length.  */
413 	skb_trim(skb, sizeof(struct sctp_remote_error) + elen);
414 
415 	/* Socket Extensions for SCTP
416 	 * 5.3.1.3 SCTP_REMOTE_ERROR
417 	 *
418 	 * sre_type:
419 	 *   It should be SCTP_REMOTE_ERROR.
420 	 */
421 	sre->sre_type = SCTP_REMOTE_ERROR;
422 
423 	/*
424 	 * Socket Extensions for SCTP
425 	 * 5.3.1.3 SCTP_REMOTE_ERROR
426 	 *
427 	 * sre_flags: 16 bits (unsigned integer)
428 	 *   Currently unused.
429 	 */
430 	sre->sre_flags = 0;
431 
432 	/* Socket Extensions for SCTP
433 	 * 5.3.1.3 SCTP_REMOTE_ERROR
434 	 *
435 	 * sre_length: sizeof (__u32)
436 	 *
437 	 * This field is the total length of the notification data,
438 	 * including the notification header.
439 	 */
440 	sre->sre_length = skb->len;
441 
442 	/* Socket Extensions for SCTP
443 	 * 5.3.1.3 SCTP_REMOTE_ERROR
444 	 *
445 	 * sre_error: 16 bits (unsigned integer)
446 	 * This value represents one of the Operational Error causes defined in
447 	 * the SCTP specification, in network byte order.
448 	 */
449 	sre->sre_error = cause;
450 
451 	/* Socket Extensions for SCTP
452 	 * 5.3.1.3 SCTP_REMOTE_ERROR
453 	 *
454 	 * sre_assoc_id: sizeof (sctp_assoc_t)
455 	 *
456 	 * The association id field, holds the identifier for the association.
457 	 * All notifications for a given association have the same association
458 	 * identifier.  For TCP style socket, this field is ignored.
459 	 */
460 	sctp_ulpevent_set_owner(event, asoc);
461 	sre->sre_assoc_id = sctp_assoc2id(asoc);
462 
463 	return event;
464 
465 fail:
466 	return NULL;
467 }
468 
469 /* Create and initialize a SCTP_SEND_FAILED notification.
470  *
471  * Socket Extensions for SCTP - draft-01
472  * 5.3.1.4 SCTP_SEND_FAILED
473  */
sctp_ulpevent_make_send_failed(const struct sctp_association * asoc,struct sctp_chunk * chunk,__u16 flags,__u32 error,gfp_t gfp)474 struct sctp_ulpevent *sctp_ulpevent_make_send_failed(
475 	const struct sctp_association *asoc, struct sctp_chunk *chunk,
476 	__u16 flags, __u32 error, gfp_t gfp)
477 {
478 	struct sctp_ulpevent *event;
479 	struct sctp_send_failed *ssf;
480 	struct sk_buff *skb;
481 
482 	/* Pull off any padding. */
483 	int len = ntohs(chunk->chunk_hdr->length);
484 
485 	/* Make skb with more room so we can prepend notification.  */
486 	skb = skb_copy_expand(chunk->skb,
487 			      sizeof(struct sctp_send_failed), /* headroom */
488 			      0,                               /* tailroom */
489 			      gfp);
490 	if (!skb)
491 		goto fail;
492 
493 	/* Pull off the common chunk header and DATA header.  */
494 	skb_pull(skb, sizeof(struct sctp_data_chunk));
495 	len -= sizeof(struct sctp_data_chunk);
496 
497 	/* Embed the event fields inside the cloned skb.  */
498 	event = sctp_skb2event(skb);
499 	sctp_ulpevent_init(event, MSG_NOTIFICATION, skb->truesize);
500 
501 	ssf = (struct sctp_send_failed *)
502 		skb_push(skb, sizeof(struct sctp_send_failed));
503 
504 	/* Socket Extensions for SCTP
505 	 * 5.3.1.4 SCTP_SEND_FAILED
506 	 *
507 	 * ssf_type:
508 	 * It should be SCTP_SEND_FAILED.
509 	 */
510 	ssf->ssf_type = SCTP_SEND_FAILED;
511 
512 	/* Socket Extensions for SCTP
513 	 * 5.3.1.4 SCTP_SEND_FAILED
514 	 *
515 	 * ssf_flags: 16 bits (unsigned integer)
516 	 * The flag value will take one of the following values
517 	 *
518 	 * SCTP_DATA_UNSENT - Indicates that the data was never put on
519 	 *                    the wire.
520 	 *
521 	 * SCTP_DATA_SENT   - Indicates that the data was put on the wire.
522 	 *                    Note that this does not necessarily mean that the
523 	 *                    data was (or was not) successfully delivered.
524 	 */
525 	ssf->ssf_flags = flags;
526 
527 	/* Socket Extensions for SCTP
528 	 * 5.3.1.4 SCTP_SEND_FAILED
529 	 *
530 	 * ssf_length: sizeof (__u32)
531 	 * This field is the total length of the notification data, including
532 	 * the notification header.
533 	 */
534 	ssf->ssf_length = sizeof(struct sctp_send_failed) + len;
535 	skb_trim(skb, ssf->ssf_length);
536 
537 	/* Socket Extensions for SCTP
538 	 * 5.3.1.4 SCTP_SEND_FAILED
539 	 *
540 	 * ssf_error: 16 bits (unsigned integer)
541 	 * This value represents the reason why the send failed, and if set,
542 	 * will be a SCTP protocol error code as defined in [SCTP] section
543 	 * 3.3.10.
544 	 */
545 	ssf->ssf_error = error;
546 
547 	/* Socket Extensions for SCTP
548 	 * 5.3.1.4 SCTP_SEND_FAILED
549 	 *
550 	 * ssf_info: sizeof (struct sctp_sndrcvinfo)
551 	 * The original send information associated with the undelivered
552 	 * message.
553 	 */
554 	memcpy(&ssf->ssf_info, &chunk->sinfo, sizeof(struct sctp_sndrcvinfo));
555 
556 	/* Per TSVWG discussion with Randy. Allow the application to
557 	 * reassemble a fragmented message.
558 	 */
559 	ssf->ssf_info.sinfo_flags = chunk->chunk_hdr->flags;
560 
561 	/* Socket Extensions for SCTP
562 	 * 5.3.1.4 SCTP_SEND_FAILED
563 	 *
564 	 * ssf_assoc_id: sizeof (sctp_assoc_t)
565 	 * The association id field, sf_assoc_id, holds the identifier for the
566 	 * association.  All notifications for a given association have the
567 	 * same association identifier.  For TCP style socket, this field is
568 	 * ignored.
569 	 */
570 	sctp_ulpevent_set_owner(event, asoc);
571 	ssf->ssf_assoc_id = sctp_assoc2id(asoc);
572 	return event;
573 
574 fail:
575 	return NULL;
576 }
577 
578 /* Create and initialize a SCTP_SHUTDOWN_EVENT notification.
579  *
580  * Socket Extensions for SCTP - draft-01
581  * 5.3.1.5 SCTP_SHUTDOWN_EVENT
582  */
sctp_ulpevent_make_shutdown_event(const struct sctp_association * asoc,__u16 flags,gfp_t gfp)583 struct sctp_ulpevent *sctp_ulpevent_make_shutdown_event(
584 	const struct sctp_association *asoc,
585 	__u16 flags, gfp_t gfp)
586 {
587 	struct sctp_ulpevent *event;
588 	struct sctp_shutdown_event *sse;
589 	struct sk_buff *skb;
590 
591 	event = sctp_ulpevent_new(sizeof(struct sctp_shutdown_event),
592 				  MSG_NOTIFICATION, gfp);
593 	if (!event)
594 		goto fail;
595 
596 	skb = sctp_event2skb(event);
597 	sse = (struct sctp_shutdown_event *)
598 		skb_put(skb, sizeof(struct sctp_shutdown_event));
599 
600 	/* Socket Extensions for SCTP
601 	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
602 	 *
603 	 * sse_type
604 	 * It should be SCTP_SHUTDOWN_EVENT
605 	 */
606 	sse->sse_type = SCTP_SHUTDOWN_EVENT;
607 
608 	/* Socket Extensions for SCTP
609 	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
610 	 *
611 	 * sse_flags: 16 bits (unsigned integer)
612 	 * Currently unused.
613 	 */
614 	sse->sse_flags = 0;
615 
616 	/* Socket Extensions for SCTP
617 	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
618 	 *
619 	 * sse_length: sizeof (__u32)
620 	 * This field is the total length of the notification data, including
621 	 * the notification header.
622 	 */
623 	sse->sse_length = sizeof(struct sctp_shutdown_event);
624 
625 	/* Socket Extensions for SCTP
626 	 * 5.3.1.5 SCTP_SHUTDOWN_EVENT
627 	 *
628 	 * sse_assoc_id: sizeof (sctp_assoc_t)
629 	 * The association id field, holds the identifier for the association.
630 	 * All notifications for a given association have the same association
631 	 * identifier.  For TCP style socket, this field is ignored.
632 	 */
633 	sctp_ulpevent_set_owner(event, asoc);
634 	sse->sse_assoc_id = sctp_assoc2id(asoc);
635 
636 	return event;
637 
638 fail:
639 	return NULL;
640 }
641 
642 /* Create and initialize a SCTP_ADAPTATION_INDICATION notification.
643  *
644  * Socket Extensions for SCTP
645  * 5.3.1.6 SCTP_ADAPTATION_INDICATION
646  */
sctp_ulpevent_make_adaptation_indication(const struct sctp_association * asoc,gfp_t gfp)647 struct sctp_ulpevent *sctp_ulpevent_make_adaptation_indication(
648 	const struct sctp_association *asoc, gfp_t gfp)
649 {
650 	struct sctp_ulpevent *event;
651 	struct sctp_adaptation_event *sai;
652 	struct sk_buff *skb;
653 
654 	event = sctp_ulpevent_new(sizeof(struct sctp_adaptation_event),
655 				  MSG_NOTIFICATION, gfp);
656 	if (!event)
657 		goto fail;
658 
659 	skb = sctp_event2skb(event);
660 	sai = (struct sctp_adaptation_event *)
661 		skb_put(skb, sizeof(struct sctp_adaptation_event));
662 
663 	sai->sai_type = SCTP_ADAPTATION_INDICATION;
664 	sai->sai_flags = 0;
665 	sai->sai_length = sizeof(struct sctp_adaptation_event);
666 	sai->sai_adaptation_ind = asoc->peer.adaptation_ind;
667 	sctp_ulpevent_set_owner(event, asoc);
668 	sai->sai_assoc_id = sctp_assoc2id(asoc);
669 
670 	return event;
671 
672 fail:
673 	return NULL;
674 }
675 
676 /* A message has been received.  Package this message as a notification
677  * to pass it to the upper layers.  Go ahead and calculate the sndrcvinfo
678  * even if filtered out later.
679  *
680  * Socket Extensions for SCTP
681  * 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
682  */
sctp_ulpevent_make_rcvmsg(struct sctp_association * asoc,struct sctp_chunk * chunk,gfp_t gfp)683 struct sctp_ulpevent *sctp_ulpevent_make_rcvmsg(struct sctp_association *asoc,
684 						struct sctp_chunk *chunk,
685 						gfp_t gfp)
686 {
687 	struct sctp_ulpevent *event = NULL;
688 	struct sk_buff *skb;
689 	size_t padding, len;
690 	int rx_count;
691 
692 	/*
693 	 * check to see if we need to make space for this
694 	 * new skb, expand the rcvbuffer if needed, or drop
695 	 * the frame
696 	 */
697 	if (asoc->ep->rcvbuf_policy)
698 		rx_count = atomic_read(&asoc->rmem_alloc);
699 	else
700 		rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc);
701 
702 	if (rx_count >= asoc->base.sk->sk_rcvbuf) {
703 
704 		if ((asoc->base.sk->sk_userlocks & SOCK_RCVBUF_LOCK) ||
705 		    (!sk_rmem_schedule(asoc->base.sk, chunk->skb->truesize)))
706 			goto fail;
707 	}
708 
709 	/* Clone the original skb, sharing the data.  */
710 	skb = skb_clone(chunk->skb, gfp);
711 	if (!skb)
712 		goto fail;
713 
714 	/* Now that all memory allocations for this chunk succeeded, we
715 	 * can mark it as received so the tsn_map is updated correctly.
716 	 */
717 	if (sctp_tsnmap_mark(&asoc->peer.tsn_map,
718 			     ntohl(chunk->subh.data_hdr->tsn)))
719 		goto fail_mark;
720 
721 	/* First calculate the padding, so we don't inadvertently
722 	 * pass up the wrong length to the user.
723 	 *
724 	 * RFC 2960 - Section 3.2  Chunk Field Descriptions
725 	 *
726 	 * The total length of a chunk(including Type, Length and Value fields)
727 	 * MUST be a multiple of 4 bytes.  If the length of the chunk is not a
728 	 * multiple of 4 bytes, the sender MUST pad the chunk with all zero
729 	 * bytes and this padding is not included in the chunk length field.
730 	 * The sender should never pad with more than 3 bytes.  The receiver
731 	 * MUST ignore the padding bytes.
732 	 */
733 	len = ntohs(chunk->chunk_hdr->length);
734 	padding = WORD_ROUND(len) - len;
735 
736 	/* Fixup cloned skb with just this chunks data.  */
737 	skb_trim(skb, chunk->chunk_end - padding - skb->data);
738 
739 	/* Embed the event fields inside the cloned skb.  */
740 	event = sctp_skb2event(skb);
741 
742 	/* Initialize event with flags 0  and correct length
743 	 * Since this is a clone of the original skb, only account for
744 	 * the data of this chunk as other chunks will be accounted separately.
745 	 */
746 	sctp_ulpevent_init(event, 0, skb->len + sizeof(struct sk_buff));
747 
748 	sctp_ulpevent_receive_data(event, asoc);
749 
750 	event->stream = ntohs(chunk->subh.data_hdr->stream);
751 	event->ssn = ntohs(chunk->subh.data_hdr->ssn);
752 	event->ppid = chunk->subh.data_hdr->ppid;
753 	if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
754 		event->flags |= SCTP_UNORDERED;
755 		event->cumtsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map);
756 	}
757 	event->tsn = ntohl(chunk->subh.data_hdr->tsn);
758 	event->msg_flags |= chunk->chunk_hdr->flags;
759 	event->iif = sctp_chunk_iif(chunk);
760 
761 	return event;
762 
763 fail_mark:
764 	kfree_skb(skb);
765 fail:
766 	return NULL;
767 }
768 
769 /* Create a partial delivery related event.
770  *
771  * 5.3.1.7 SCTP_PARTIAL_DELIVERY_EVENT
772  *
773  *   When a receiver is engaged in a partial delivery of a
774  *   message this notification will be used to indicate
775  *   various events.
776  */
sctp_ulpevent_make_pdapi(const struct sctp_association * asoc,__u32 indication,gfp_t gfp)777 struct sctp_ulpevent *sctp_ulpevent_make_pdapi(
778 	const struct sctp_association *asoc, __u32 indication,
779 	gfp_t gfp)
780 {
781 	struct sctp_ulpevent *event;
782 	struct sctp_pdapi_event *pd;
783 	struct sk_buff *skb;
784 
785 	event = sctp_ulpevent_new(sizeof(struct sctp_pdapi_event),
786 				  MSG_NOTIFICATION, gfp);
787 	if (!event)
788 		goto fail;
789 
790 	skb = sctp_event2skb(event);
791 	pd = (struct sctp_pdapi_event *)
792 		skb_put(skb, sizeof(struct sctp_pdapi_event));
793 
794 	/* pdapi_type
795 	 *   It should be SCTP_PARTIAL_DELIVERY_EVENT
796 	 *
797 	 * pdapi_flags: 16 bits (unsigned integer)
798 	 *   Currently unused.
799 	 */
800 	pd->pdapi_type = SCTP_PARTIAL_DELIVERY_EVENT;
801 	pd->pdapi_flags = 0;
802 
803 	/* pdapi_length: 32 bits (unsigned integer)
804 	 *
805 	 * This field is the total length of the notification data, including
806 	 * the notification header.  It will generally be sizeof (struct
807 	 * sctp_pdapi_event).
808 	 */
809 	pd->pdapi_length = sizeof(struct sctp_pdapi_event);
810 
811 	/*  pdapi_indication: 32 bits (unsigned integer)
812 	 *
813 	 * This field holds the indication being sent to the application.
814 	 */
815 	pd->pdapi_indication = indication;
816 
817 	/*  pdapi_assoc_id: sizeof (sctp_assoc_t)
818 	 *
819 	 * The association id field, holds the identifier for the association.
820 	 */
821 	sctp_ulpevent_set_owner(event, asoc);
822 	pd->pdapi_assoc_id = sctp_assoc2id(asoc);
823 
824 	return event;
825 fail:
826 	return NULL;
827 }
828 
sctp_ulpevent_make_authkey(const struct sctp_association * asoc,__u16 key_id,__u32 indication,gfp_t gfp)829 struct sctp_ulpevent *sctp_ulpevent_make_authkey(
830 	const struct sctp_association *asoc, __u16 key_id,
831 	__u32 indication, gfp_t gfp)
832 {
833 	struct sctp_ulpevent *event;
834 	struct sctp_authkey_event *ak;
835 	struct sk_buff *skb;
836 
837 	event = sctp_ulpevent_new(sizeof(struct sctp_authkey_event),
838 				  MSG_NOTIFICATION, gfp);
839 	if (!event)
840 		goto fail;
841 
842 	skb = sctp_event2skb(event);
843 	ak = (struct sctp_authkey_event *)
844 		skb_put(skb, sizeof(struct sctp_authkey_event));
845 
846 	ak->auth_type = SCTP_AUTHENTICATION_INDICATION;
847 	ak->auth_flags = 0;
848 	ak->auth_length = sizeof(struct sctp_authkey_event);
849 
850 	ak->auth_keynumber = key_id;
851 	ak->auth_altkeynumber = 0;
852 	ak->auth_indication = indication;
853 
854 	/*
855 	 * The association id field, holds the identifier for the association.
856 	 */
857 	sctp_ulpevent_set_owner(event, asoc);
858 	ak->auth_assoc_id = sctp_assoc2id(asoc);
859 
860 	return event;
861 fail:
862 	return NULL;
863 }
864 
865 
866 /* Return the notification type, assuming this is a notification
867  * event.
868  */
sctp_ulpevent_get_notification_type(const struct sctp_ulpevent * event)869 __u16 sctp_ulpevent_get_notification_type(const struct sctp_ulpevent *event)
870 {
871 	union sctp_notification *notification;
872 	struct sk_buff *skb;
873 
874 	skb = sctp_event2skb(event);
875 	notification = (union sctp_notification *) skb->data;
876 	return notification->sn_header.sn_type;
877 }
878 
879 /* Copy out the sndrcvinfo into a msghdr.  */
sctp_ulpevent_read_sndrcvinfo(const struct sctp_ulpevent * event,struct msghdr * msghdr)880 void sctp_ulpevent_read_sndrcvinfo(const struct sctp_ulpevent *event,
881 				   struct msghdr *msghdr)
882 {
883 	struct sctp_sndrcvinfo sinfo;
884 
885 	if (sctp_ulpevent_is_notification(event))
886 		return;
887 
888 	/* Sockets API Extensions for SCTP
889 	 * Section 5.2.2 SCTP Header Information Structure (SCTP_SNDRCV)
890 	 *
891 	 * sinfo_stream: 16 bits (unsigned integer)
892 	 *
893 	 * For recvmsg() the SCTP stack places the message's stream number in
894 	 * this value.
895 	*/
896 	sinfo.sinfo_stream = event->stream;
897 	/* sinfo_ssn: 16 bits (unsigned integer)
898 	 *
899 	 * For recvmsg() this value contains the stream sequence number that
900 	 * the remote endpoint placed in the DATA chunk.  For fragmented
901 	 * messages this is the same number for all deliveries of the message
902 	 * (if more than one recvmsg() is needed to read the message).
903 	 */
904 	sinfo.sinfo_ssn = event->ssn;
905 	/* sinfo_ppid: 32 bits (unsigned integer)
906 	 *
907 	 * In recvmsg() this value is
908 	 * the same information that was passed by the upper layer in the peer
909 	 * application.  Please note that byte order issues are NOT accounted
910 	 * for and this information is passed opaquely by the SCTP stack from
911 	 * one end to the other.
912 	 */
913 	sinfo.sinfo_ppid = event->ppid;
914 	/* sinfo_flags: 16 bits (unsigned integer)
915 	 *
916 	 * This field may contain any of the following flags and is composed of
917 	 * a bitwise OR of these values.
918 	 *
919 	 * recvmsg() flags:
920 	 *
921 	 * SCTP_UNORDERED - This flag is present when the message was sent
922 	 *                 non-ordered.
923 	 */
924 	sinfo.sinfo_flags = event->flags;
925 	/* sinfo_tsn: 32 bit (unsigned integer)
926 	 *
927 	 * For the receiving side, this field holds a TSN that was
928 	 * assigned to one of the SCTP Data Chunks.
929 	 */
930 	sinfo.sinfo_tsn = event->tsn;
931 	/* sinfo_cumtsn: 32 bit (unsigned integer)
932 	 *
933 	 * This field will hold the current cumulative TSN as
934 	 * known by the underlying SCTP layer.  Note this field is
935 	 * ignored when sending and only valid for a receive
936 	 * operation when sinfo_flags are set to SCTP_UNORDERED.
937 	 */
938 	sinfo.sinfo_cumtsn = event->cumtsn;
939 	/* sinfo_assoc_id: sizeof (sctp_assoc_t)
940 	 *
941 	 * The association handle field, sinfo_assoc_id, holds the identifier
942 	 * for the association announced in the COMMUNICATION_UP notification.
943 	 * All notifications for a given association have the same identifier.
944 	 * Ignored for one-to-one style sockets.
945 	 */
946 	sinfo.sinfo_assoc_id = sctp_assoc2id(event->asoc);
947 
948 	/* context value that is set via SCTP_CONTEXT socket option. */
949 	sinfo.sinfo_context = event->asoc->default_rcv_context;
950 
951 	/* These fields are not used while receiving. */
952 	sinfo.sinfo_timetolive = 0;
953 
954 	put_cmsg(msghdr, IPPROTO_SCTP, SCTP_SNDRCV,
955 		 sizeof(struct sctp_sndrcvinfo), (void *)&sinfo);
956 }
957 
958 /* Do accounting for bytes received and hold a reference to the association
959  * for each skb.
960  */
sctp_ulpevent_receive_data(struct sctp_ulpevent * event,struct sctp_association * asoc)961 static void sctp_ulpevent_receive_data(struct sctp_ulpevent *event,
962 				       struct sctp_association *asoc)
963 {
964 	struct sk_buff *skb, *frag;
965 
966 	skb = sctp_event2skb(event);
967 	/* Set the owner and charge rwnd for bytes received.  */
968 	sctp_ulpevent_set_owner(event, asoc);
969 	sctp_assoc_rwnd_decrease(asoc, skb_headlen(skb));
970 
971 	if (!skb->data_len)
972 		return;
973 
974 	/* Note:  Not clearing the entire event struct as this is just a
975 	 * fragment of the real event.  However, we still need to do rwnd
976 	 * accounting.
977 	 * In general, the skb passed from IP can have only 1 level of
978 	 * fragments. But we allow multiple levels of fragments.
979 	 */
980 	skb_walk_frags(skb, frag)
981 		sctp_ulpevent_receive_data(sctp_skb2event(frag), asoc);
982 }
983 
984 /* Do accounting for bytes just read by user and release the references to
985  * the association.
986  */
sctp_ulpevent_release_data(struct sctp_ulpevent * event)987 static void sctp_ulpevent_release_data(struct sctp_ulpevent *event)
988 {
989 	struct sk_buff *skb, *frag;
990 	unsigned int	len;
991 
992 	/* Current stack structures assume that the rcv buffer is
993 	 * per socket.   For UDP style sockets this is not true as
994 	 * multiple associations may be on a single UDP-style socket.
995 	 * Use the local private area of the skb to track the owning
996 	 * association.
997 	 */
998 
999 	skb = sctp_event2skb(event);
1000 	len = skb->len;
1001 
1002 	if (!skb->data_len)
1003 		goto done;
1004 
1005 	/* Don't forget the fragments. */
1006 	skb_walk_frags(skb, frag) {
1007 		/* NOTE:  skb_shinfos are recursive. Although IP returns
1008 		 * skb's with only 1 level of fragments, SCTP reassembly can
1009 		 * increase the levels.
1010 		 */
1011 		sctp_ulpevent_release_frag_data(sctp_skb2event(frag));
1012 	}
1013 
1014 done:
1015 	sctp_assoc_rwnd_increase(event->asoc, len);
1016 	sctp_ulpevent_release_owner(event);
1017 }
1018 
sctp_ulpevent_release_frag_data(struct sctp_ulpevent * event)1019 static void sctp_ulpevent_release_frag_data(struct sctp_ulpevent *event)
1020 {
1021 	struct sk_buff *skb, *frag;
1022 
1023 	skb = sctp_event2skb(event);
1024 
1025 	if (!skb->data_len)
1026 		goto done;
1027 
1028 	/* Don't forget the fragments. */
1029 	skb_walk_frags(skb, frag) {
1030 		/* NOTE:  skb_shinfos are recursive. Although IP returns
1031 		 * skb's with only 1 level of fragments, SCTP reassembly can
1032 		 * increase the levels.
1033 		 */
1034 		sctp_ulpevent_release_frag_data(sctp_skb2event(frag));
1035 	}
1036 
1037 done:
1038 	sctp_ulpevent_release_owner(event);
1039 }
1040 
1041 /* Free a ulpevent that has an owner.  It includes releasing the reference
1042  * to the owner, updating the rwnd in case of a DATA event and freeing the
1043  * skb.
1044  */
sctp_ulpevent_free(struct sctp_ulpevent * event)1045 void sctp_ulpevent_free(struct sctp_ulpevent *event)
1046 {
1047 	if (sctp_ulpevent_is_notification(event))
1048 		sctp_ulpevent_release_owner(event);
1049 	else
1050 		sctp_ulpevent_release_data(event);
1051 
1052 	kfree_skb(sctp_event2skb(event));
1053 }
1054 
1055 /* Purge the skb lists holding ulpevents. */
sctp_queue_purge_ulpevents(struct sk_buff_head * list)1056 void sctp_queue_purge_ulpevents(struct sk_buff_head *list)
1057 {
1058 	struct sk_buff *skb;
1059 	while ((skb = skb_dequeue(list)) != NULL)
1060 		sctp_ulpevent_free(sctp_skb2event(skb));
1061 }
1062