[linux.git] / net / sctp / chunk.c

/* SCTP kernel implementation
 * (C) Copyright IBM Corp. 2003, 2004
 *
 * This file is part of the SCTP kernel implementation
 *
 * This file contains the code relating the chunk abstraction.
 *
 * This SCTP implementation is free software;
 * you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This SCTP implementation is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *                 ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <[email protected]>
 *
 * Or submit a bug report through the following website:
 *    http://www.sf.net/projects/lksctp
 *
 * Written or modified by:
 *    Jon Grimm             <[email protected]>
 *    Sridhar Samudrala     <[email protected]>
 *
 * Any bugs reported given to us we will try to fix... any fixes shared will
 * be incorporated into the next SCTP release.
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>

/* This file is mostly in anticipation of future work, but initially
 * populate with fragment tracking for an outbound message.
 */

/* Initialize datamsg from memory. */
static void sctp_datamsg_init(struct sctp_datamsg *msg)
{
	atomic_set(&msg->refcnt, 1);
	msg->send_failed = 0;
	msg->send_error = 0;
	msg->can_abandon = 0;
	msg->expires_at = 0;
	INIT_LIST_HEAD(&msg->chunks);
}

/* Allocate and initialize datamsg. */
SCTP_STATIC struct sctp_datamsg *sctp_datamsg_new(gfp_t gfp)
{
	struct sctp_datamsg *msg;
	msg = kmalloc(sizeof(struct sctp_datamsg), gfp);
	if (msg) {
		sctp_datamsg_init(msg);
		SCTP_DBG_OBJCNT_INC(datamsg);
	}
	return msg;
}

/* Final destructruction of datamsg memory. */
static void sctp_datamsg_destroy(struct sctp_datamsg *msg)
{
	struct list_head *pos, *temp;
	struct sctp_chunk *chunk;
	struct sctp_sock *sp;
	struct sctp_ulpevent *ev;
	struct sctp_association *asoc = NULL;
	int error = 0, notify;

	/* If we failed, we may need to notify. */
	notify = msg->send_failed ? -1 : 0;

	/* Release all references. */
	list_for_each_safe(pos, temp, &msg->chunks) {
		list_del_init(pos);
		chunk = list_entry(pos, struct sctp_chunk, frag_list);
		/* Check whether we _really_ need to notify. */
		if (notify < 0) {
			asoc = chunk->asoc;
			if (msg->send_error)
				error = msg->send_error;
			else
				error = asoc->outqueue.error;

			sp = sctp_sk(asoc->base.sk);
			notify = sctp_ulpevent_type_enabled(SCTP_SEND_FAILED,
							    &sp->subscribe);
		}

		/* Generate a SEND FAILED event only if enabled. */
		if (notify > 0) {
			int sent;
			if (chunk->has_tsn)
				sent = SCTP_DATA_SENT;
			else
				sent = SCTP_DATA_UNSENT;

			ev = sctp_ulpevent_make_send_failed(asoc, chunk, sent,
							    error, GFP_ATOMIC);
			if (ev)
				sctp_ulpq_tail_event(&asoc->ulpq, ev);
		}

		sctp_chunk_put(chunk);
	}

	SCTP_DBG_OBJCNT_DEC(datamsg);
	kfree(msg);
}

/* Hold a reference. */
static void sctp_datamsg_hold(struct sctp_datamsg *msg)
{
	atomic_inc(&msg->refcnt);
}

/* Release a reference. */
void sctp_datamsg_put(struct sctp_datamsg *msg)
{
	if (atomic_dec_and_test(&msg->refcnt))
		sctp_datamsg_destroy(msg);
}

/* Assign a chunk to this datamsg. */
static void sctp_datamsg_assign(struct sctp_datamsg *msg, struct sctp_chunk *chunk)
{
	sctp_datamsg_hold(msg);
	chunk->msg = msg;
}


/* A data chunk can have a maximum payload of (2^16 - 20).  Break
 * down any such message into smaller chunks.  Opportunistically, fragment
 * the chunks down to the current MTU constraints.  We may get refragmented
 * later if the PMTU changes, but it is _much better_ to fragment immediately
 * with a reasonable guess than always doing our fragmentation on the
 * soft-interrupt.
 */
struct sctp_datamsg *sctp_datamsg_from_user(struct sctp_association *asoc,
					    struct sctp_sndrcvinfo *sinfo,
					    struct msghdr *msgh, int msg_len)
{
	int max, whole, i, offset, over, err;
	int len, first_len;
	struct sctp_chunk *chunk;
	struct sctp_datamsg *msg;
	struct list_head *pos, *temp;
	__u8 frag;

	msg = sctp_datamsg_new(GFP_KERNEL);
	if (!msg)
		return NULL;

	/* Note: Calculate this outside of the loop, so that all fragments
	 * have the same expiration.
	 */
	if (sinfo->sinfo_timetolive) {
		/* sinfo_timetolive is in milliseconds */
		msg->expires_at = jiffies +
				    msecs_to_jiffies(sinfo->sinfo_timetolive);
		msg->can_abandon = 1;
		SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n",
				  __func__, msg, msg->expires_at, jiffies);
	}

	max = asoc->frag_point;

	/* If the the peer requested that we authenticate DATA chunks
	 * we need to accound for bundling of the AUTH chunks along with
	 * DATA.
	 */
	if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
		struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);

		if (hmac_desc)
			max -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
					    hmac_desc->hmac_len);
	}

	whole = 0;
	first_len = max;

	/* Encourage Cookie-ECHO bundling. */
	if (asoc->state < SCTP_STATE_COOKIE_ECHOED) {
		whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN);

		/* Account for the DATA to be bundled with the COOKIE-ECHO. */
		if (whole) {
			first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN;
			msg_len -= first_len;
			whole = 1;
		}
	}

	/* How many full sized?  How many bytes leftover? */
	whole += msg_len / max;
	over = msg_len % max;
	offset = 0;

	if ((whole > 1) || (whole && over))
		SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS);

	/* Create chunks for all the full sized DATA chunks. */
	for (i=0, len=first_len; i < whole; i++) {
		frag = SCTP_DATA_MIDDLE_FRAG;

		if (0 == i)
			frag |= SCTP_DATA_FIRST_FRAG;

		if ((i == (whole - 1)) && !over)
			frag |= SCTP_DATA_LAST_FRAG;

		chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);

		if (!chunk)
			goto errout;
		err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
		if (err < 0)
			goto errout;

		offset += len;

		/* Put the chunk->skb back into the form expected by send.  */
		__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
			   - (__u8 *)chunk->skb->data);

		sctp_datamsg_assign(msg, chunk);
		list_add_tail(&chunk->frag_list, &msg->chunks);

		/* The first chunk, the first chunk was likely short
		 * to allow bundling, so reset to full size.
		 */
		if (0 == i)
			len = max;
	}

	/* .. now the leftover bytes. */
	if (over) {
		if (!whole)
			frag = SCTP_DATA_NOT_FRAG;
		else
			frag = SCTP_DATA_LAST_FRAG;

		chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);

		if (!chunk)
			goto errout;

		err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov);

		/* Put the chunk->skb back into the form expected by send.  */
		__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
			   - (__u8 *)chunk->skb->data);
		if (err < 0)
			goto errout;

		sctp_datamsg_assign(msg, chunk);
		list_add_tail(&chunk->frag_list, &msg->chunks);
	}

	return msg;

errout:
	list_for_each_safe(pos, temp, &msg->chunks) {
		list_del_init(pos);
		chunk = list_entry(pos, struct sctp_chunk, frag_list);
		sctp_chunk_free(chunk);
	}
	sctp_datamsg_put(msg);
	return NULL;
}

/* Check whether this message has expired. */
int sctp_chunk_abandoned(struct sctp_chunk *chunk)
{
	struct sctp_datamsg *msg = chunk->msg;

	if (!msg->can_abandon)
		return 0;

	if (time_after(jiffies, msg->expires_at))
		return 1;

	return 0;
}

/* This chunk (and consequently entire message) has failed in its sending. */
void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
{
	chunk->msg->send_failed = 1;
	chunk->msg->send_error = error;
}
Commit	Line	Data
60c778b2	1	/* SCTP kernel implementation
1da177e4 LT	2	* (C) Copyright IBM Corp. 2003, 2004
1da177e4 LT	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 <[email protected]>
	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 <[email protected]>
	34	* Sridhar Samudrala <[email protected]>
	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);
e8c38751 LZ	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;
	161	struct sctp_chunk *chunk;
	162	struct sctp_datamsg *msg;
	163	struct list_head pos, temp;
	164	__u8 frag;
	165
	166	msg = sctp_datamsg_new(GFP_KERNEL);
	167	if (!msg)
	168	return NULL;
	169
	170	/* Note: Calculate this outside of the loop, so that all fragments
	171	* have the same expiration.
	172	*/
	173	if (sinfo->sinfo_timetolive) {
	174	/* sinfo_timetolive is in milliseconds */
	175	msg->expires_at = jiffies +
	176	msecs_to_jiffies(sinfo->sinfo_timetolive);
	177	msg->can_abandon = 1;
	178	SCTP_DEBUG_PRINTK("%s: msg:%p expires_at: %ld jiffies:%ld\n",
0dc47877	179	__func__, msg, msg->expires_at, jiffies);
1da177e4 LT	180	}
	181
	182	max = asoc->frag_point;
	183
4cd57c80 VY	184	/* If the the peer requested that we authenticate DATA chunks
	185	* we need to accound for bundling of the AUTH chunks along with
	186	* DATA.
	187	*/
	188	if (sctp_auth_send_cid(SCTP_CID_DATA, asoc)) {
	189	struct sctp_hmac *hmac_desc = sctp_auth_asoc_get_hmac(asoc);
	190
	191	if (hmac_desc)
	192	max -= WORD_ROUND(sizeof(sctp_auth_chunk_t) +
	193	hmac_desc->hmac_len);
	194	}
	195
1da177e4 LT	196	whole = 0;
	197	first_len = max;
	198
	199	/* Encourage Cookie-ECHO bundling. */
	200	if (asoc->state < SCTP_STATE_COOKIE_ECHOED) {
	201	whole = msg_len / (max - SCTP_ARBITRARY_COOKIE_ECHO_LEN);
	202
	203	/* Account for the DATA to be bundled with the COOKIE-ECHO. */
	204	if (whole) {
	205	first_len = max - SCTP_ARBITRARY_COOKIE_ECHO_LEN;
	206	msg_len -= first_len;
	207	whole = 1;
	208	}
	209	}
	210
	211	/* How many full sized? How many bytes leftover? */
	212	whole += msg_len / max;
	213	over = msg_len % max;
	214	offset = 0;
	215
	216	if ((whole > 1) \|\| (whole && over))
	217	SCTP_INC_STATS_USER(SCTP_MIB_FRAGUSRMSGS);
	218
	219	/* Create chunks for all the full sized DATA chunks. */
	220	for (i=0, len=first_len; i < whole; i++) {
	221	frag = SCTP_DATA_MIDDLE_FRAG;
	222
	223	if (0 == i)
	224	frag \|= SCTP_DATA_FIRST_FRAG;
	225
	226	if ((i == (whole - 1)) && !over)
	227	frag \|= SCTP_DATA_LAST_FRAG;
	228
	229	chunk = sctp_make_datafrag_empty(asoc, sinfo, len, frag, 0);
	230
	231	if (!chunk)
	232	goto errout;
	233	err = sctp_user_addto_chunk(chunk, offset, len, msgh->msg_iov);
	234	if (err < 0)
	235	goto errout;
	236
	237	offset += len;
	238
	239	/* Put the chunk->skb back into the form expected by send. */
	240	__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
	241	- (__u8 *)chunk->skb->data);
	242
	243	sctp_datamsg_assign(msg, chunk);
	244	list_add_tail(&chunk->frag_list, &msg->chunks);
	245
	246	/* The first chunk, the first chunk was likely short
	247	* to allow bundling, so reset to full size.
	248	*/
	249	if (0 == i)
	250	len = max;
	251	}
	252
	253	/* .. now the leftover bytes. */
	254	if (over) {
	255	if (!whole)
	256	frag = SCTP_DATA_NOT_FRAG;
	257	else
	258	frag = SCTP_DATA_LAST_FRAG;
	259
260	chunk = sctp_make_datafrag_empty(asoc, sinfo, over, frag, 0);
261
262	if (!chunk)
263	goto errout;
264
265	err = sctp_user_addto_chunk(chunk, offset, over,msgh->msg_iov);
266
267	/* Put the chunk->skb back into the form expected by send. */
268	__skb_pull(chunk->skb, (__u8 *)chunk->chunk_hdr
269	- (__u8 *)chunk->skb->data);
270	if (err < 0)
271	goto errout;
272
273	sctp_datamsg_assign(msg, chunk);
274	list_add_tail(&chunk->frag_list, &msg->chunks);
275	}
276
277	return msg;
278
279	errout:
280	list_for_each_safe(pos, temp, &msg->chunks) {
281	list_del_init(pos);
282	chunk = list_entry(pos, struct sctp_chunk, frag_list);
283	sctp_chunk_free(chunk);
284	}
80445cfb	285	sctp_datamsg_put(msg);
1da177e4 LT	286	return NULL;
	287	}
	288
	289	/* Check whether this message has expired. */
	290	int sctp_chunk_abandoned(struct sctp_chunk *chunk)
	291	{
	292	struct sctp_datamsg *msg = chunk->msg;
	293
	294	if (!msg->can_abandon)
	295	return 0;
	296
	297	if (time_after(jiffies, msg->expires_at))
	298	return 1;
	299
	300	return 0;
	301	}
	302
	303	/* This chunk (and consequently entire message) has failed in its sending. */
	304	void sctp_chunk_fail(struct sctp_chunk *chunk, int error)
	305	{
	306	chunk->msg->send_failed = 1;
	307	chunk->msg->send_error = error;
	308	}