[linux-2.6-block.git] / net / sctp / inqueue.c

/* SCTP kernel implementation
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2002 International Business Machines, Corp.
 *
 * This file is part of the SCTP kernel implementation
 *
 * These functions are the methods for accessing the SCTP inqueue.
 *
 * An SCTP inqueue is a queue into which you push SCTP packets
 * (which might be bundles or fragments of chunks) and out of which you
 * pop SCTP whole chunks.
 *
 * 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, see
 * <http://www.gnu.org/licenses/>.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Karl Knutson <karl@athena.chicago.il.us>
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
#include <linux/interrupt.h>
#include <linux/slab.h>

/* Initialize an SCTP inqueue.  */
void sctp_inq_init(struct sctp_inq *queue)
{
	INIT_LIST_HEAD(&queue->in_chunk_list);
	queue->in_progress = NULL;

	/* Create a task for delivering data.  */
	INIT_WORK(&queue->immediate, NULL);
}

/* Release the memory associated with an SCTP inqueue.  */
void sctp_inq_free(struct sctp_inq *queue)
{
	struct sctp_chunk *chunk, *tmp;

	/* Empty the queue.  */
	list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) {
		list_del_init(&chunk->list);
		sctp_chunk_free(chunk);
	}

	/* If there is a packet which is currently being worked on,
	 * free it as well.
	 */
	if (queue->in_progress) {
		sctp_chunk_free(queue->in_progress);
		queue->in_progress = NULL;
	}
}

/* Put a new packet in an SCTP inqueue.
 * We assume that packet->sctp_hdr is set and in host byte order.
 */
void sctp_inq_push(struct sctp_inq *q, struct sctp_chunk *chunk)
{
	/* Directly call the packet handling routine. */
	if (chunk->rcvr->dead) {
		sctp_chunk_free(chunk);
		return;
	}

	/* We are now calling this either from the soft interrupt
	 * or from the backlog processing.
	 * Eventually, we should clean up inqueue to not rely
	 * on the BH related data structures.
	 */
	list_add_tail(&chunk->list, &q->in_chunk_list);
	if (chunk->asoc)
		chunk->asoc->stats.ipackets++;
	q->immediate.func(&q->immediate);
}

/* Peek at the next chunk on the inqeue. */
struct sctp_chunkhdr *sctp_inq_peek(struct sctp_inq *queue)
{
	struct sctp_chunk *chunk;
	sctp_chunkhdr_t *ch = NULL;

	chunk = queue->in_progress;
	/* If there is no more chunks in this packet, say so */
	if (chunk->singleton ||
	    chunk->end_of_packet ||
	    chunk->pdiscard)
		    return NULL;

	ch = (sctp_chunkhdr_t *)chunk->chunk_end;

	return ch;
}


/* Extract a chunk from an SCTP inqueue.
 *
 * WARNING:  If you need to put the chunk on another queue, you need to
 * make a shallow copy (clone) of it.
 */
struct sctp_chunk *sctp_inq_pop(struct sctp_inq *queue)
{
	struct sctp_chunk *chunk;
	sctp_chunkhdr_t *ch = NULL;

	/* The assumption is that we are safe to process the chunks
	 * at this time.
	 */

	if ((chunk = queue->in_progress)) {
		/* There is a packet that we have been working on.
		 * Any post processing work to do before we move on?
		 */
		if (chunk->singleton ||
		    chunk->end_of_packet ||
		    chunk->pdiscard) {
			sctp_chunk_free(chunk);
			chunk = queue->in_progress = NULL;
		} else {
			/* Nothing to do. Next chunk in the packet, please. */
			ch = (sctp_chunkhdr_t *) chunk->chunk_end;

			/* Force chunk->skb->data to chunk->chunk_end.  */
			skb_pull(chunk->skb,
				 chunk->chunk_end - chunk->skb->data);

			/* Verify that we have at least chunk headers
			 * worth of buffer left.
			 */
			if (skb_headlen(chunk->skb) < sizeof(sctp_chunkhdr_t)) {
				sctp_chunk_free(chunk);
				chunk = queue->in_progress = NULL;
			}
		}
	}

	/* Do we need to take the next packet out of the queue to process? */
	if (!chunk) {
		struct list_head *entry;

		/* Is the queue empty?  */
		if (list_empty(&queue->in_chunk_list))
			return NULL;

		entry = queue->in_chunk_list.next;
		chunk = queue->in_progress =
			list_entry(entry, struct sctp_chunk, list);
		list_del_init(entry);

		/* This is the first chunk in the packet.  */
		chunk->singleton = 1;
		ch = (sctp_chunkhdr_t *) chunk->skb->data;
		chunk->data_accepted = 0;
	}

	chunk->chunk_hdr = ch;
	chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
	/* In the unlikely case of an IP reassembly, the skb could be
	 * non-linear. If so, update chunk_end so that it doesn't go past
	 * the skb->tail.
	 */
	if (unlikely(skb_is_nonlinear(chunk->skb))) {
		if (chunk->chunk_end > skb_tail_pointer(chunk->skb))
			chunk->chunk_end = skb_tail_pointer(chunk->skb);
	}
	skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
	chunk->subh.v = NULL; /* Subheader is no longer valid.  */

	if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) {
		/* This is not a singleton */
		chunk->singleton = 0;
	} else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
		/* RFC 2960, Section 6.10  Bundling
		 *
		 * Partial chunks MUST NOT be placed in an SCTP packet.
		 * If the receiver detects a partial chunk, it MUST drop
		 * the chunk.
		 *
		 * Since the end of the chunk is past the end of our buffer
		 * (which contains the whole packet, we can freely discard
		 * the whole packet.
		 */
		sctp_chunk_free(chunk);
		chunk = queue->in_progress = NULL;

		return NULL;
	} else {
		/* We are at the end of the packet, so mark the chunk
		 * in case we need to send a SACK.
		 */
		chunk->end_of_packet = 1;
	}

	pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n",
		 chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),
		 ntohs(chunk->chunk_hdr->length), chunk->skb->len);

	return chunk;
}

/* Set a top-half handler.
 *
 * Originally, we the top-half handler was scheduled as a BH.  We now
 * call the handler directly in sctp_inq_push() at a time that
 * we know we are lock safe.
 * The intent is that this routine will pull stuff out of the
 * inqueue and process it.
 */
void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback)
{
	INIT_WORK(&q->immediate, callback);
}
Commit	Line	Data
60c778b2	1	/* SCTP kernel implementation
1da177e4 LT	2	* Copyright (c) 1999-2000 Cisco, Inc.
	3	* Copyright (c) 1999-2001 Motorola, Inc.
	4	* Copyright (c) 2002 International Business Machines, Corp.
d808ad9a	5	*
60c778b2	6	* This file is part of the SCTP kernel implementation
d808ad9a	7	*
1da177e4 LT	8	* These functions are the methods for accessing the SCTP inqueue.
	9	*
	10	* An SCTP inqueue is a queue into which you push SCTP packets
	11	* (which might be bundles or fragments of chunks) and out of which you
	12	* pop SCTP whole chunks.
d808ad9a	13	*
60c778b2	14	* This SCTP implementation is free software;
d808ad9a	15	* you can redistribute it and/or modify it under the terms of
1da177e4 LT	16	* the GNU General Public License as published by
	17	* the Free Software Foundation; either version 2, or (at your option)
	18	* any later version.
d808ad9a	19	*
60c778b2	20	* This SCTP implementation is distributed in the hope that it
1da177e4 LT	21	* will be useful, but WITHOUT ANY WARRANTY; without even the implied
	22	* ************************
	23	* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
	24	* See the GNU General Public License for more details.
d808ad9a	25	*
1da177e4	26	* You should have received a copy of the GNU General Public License
4b2f13a2 JK	27	* along with GNU CC; see the file COPYING. If not, see
4b2f13a2 JK	28	* <http://www.gnu.org/licenses/>.
d808ad9a	29	*
1da177e4 LT	30	* Please send any bug reports or fixes you make to the
1da177e4 LT	31	* email address(es):
91705c61	32	* lksctp developers <linux-sctp@vger.kernel.org>
d808ad9a	33	*
d808ad9a	34	* Written or modified by:
1da177e4 LT	35	* La Monte H.P. Yarroll <piggy@acm.org>
1da177e4 LT	36	* Karl Knutson <karl@athena.chicago.il.us>
1da177e4 LT	37	*/
1da177e4 LT	38
145ce502 JP	39	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
145ce502 JP	40
1da177e4 LT	41	#include <net/sctp/sctp.h>
	42	#include <net/sctp/sm.h>
	43	#include <linux/interrupt.h>
5a0e3ad6	44	#include <linux/slab.h>
1da177e4 LT	45
	46	/* Initialize an SCTP inqueue. */
	47	void sctp_inq_init(struct sctp_inq *queue)
	48	{
79af02c2	49	INIT_LIST_HEAD(&queue->in_chunk_list);
1da177e4 LT	50	queue->in_progress = NULL;
	51
	52	/* Create a task for delivering data. */
c4028958	53	INIT_WORK(&queue->immediate, NULL);
1da177e4 LT	54	}
	55
	56	/* Release the memory associated with an SCTP inqueue. */
	57	void sctp_inq_free(struct sctp_inq *queue)
	58	{
79af02c2	59	struct sctp_chunk chunk, tmp;
1da177e4 LT	60
1da177e4 LT	61	/* Empty the queue. */
79af02c2 DM	62	list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) {
79af02c2 DM	63	list_del_init(&chunk->list);
1da177e4	64	sctp_chunk_free(chunk);
79af02c2	65	}
1da177e4 LT	66
	67	/* If there is a packet which is currently being worked on,
	68	* free it as well.
	69	*/
7a48f923	70	if (queue->in_progress) {
1da177e4	71	sctp_chunk_free(queue->in_progress);
7a48f923 SS	72	queue->in_progress = NULL;
7a48f923 SS	73	}
1da177e4 LT	74	}
	75
	76	/* Put a new packet in an SCTP inqueue.
	77	* We assume that packet->sctp_hdr is set and in host byte order.
	78	*/
ac0b0462	79	void sctp_inq_push(struct sctp_inq q, struct sctp_chunk chunk)
1da177e4 LT	80	{
1da177e4 LT	81	/* Directly call the packet handling routine. */
027f6e1a VY	82	if (chunk->rcvr->dead) {
	83	sctp_chunk_free(chunk);
	84	return;
	85	}
1da177e4 LT	86
	87	/* We are now calling this either from the soft interrupt
	88	* or from the backlog processing.
	89	* Eventually, we should clean up inqueue to not rely
	90	* on the BH related data structures.
	91	*/
ac0b0462	92	list_add_tail(&chunk->list, &q->in_chunk_list);
196d6759 MB	93	if (chunk->asoc)
196d6759 MB	94	chunk->asoc->stats.ipackets++;
c4028958	95	q->immediate.func(&q->immediate);
1da177e4 LT	96	}
1da177e4 LT	97
bbd0d598 VY	98	/* Peek at the next chunk on the inqeue. */
	99	struct sctp_chunkhdr sctp_inq_peek(struct sctp_inq queue)
	100	{
	101	struct sctp_chunk *chunk;
	102	sctp_chunkhdr_t *ch = NULL;
	103
	104	chunk = queue->in_progress;
	105	/* If there is no more chunks in this packet, say so */
	106	if (chunk->singleton \|\|
	107	chunk->end_of_packet \|\|
	108	chunk->pdiscard)
	109	return NULL;
	110
	111	ch = (sctp_chunkhdr_t *)chunk->chunk_end;
	112
	113	return ch;
	114	}
	115
	116
1da177e4 LT	117	/* Extract a chunk from an SCTP inqueue.
	118	*
	119	* WARNING: If you need to put the chunk on another queue, you need to
	120	* make a shallow copy (clone) of it.
	121	*/
	122	struct sctp_chunk sctp_inq_pop(struct sctp_inq queue)
	123	{
	124	struct sctp_chunk *chunk;
	125	sctp_chunkhdr_t *ch = NULL;
	126
	127	/* The assumption is that we are safe to process the chunks
	128	* at this time.
	129	*/
	130
	131	if ((chunk = queue->in_progress)) {
	132	/* There is a packet that we have been working on.
	133	* Any post processing work to do before we move on?
	134	*/
	135	if (chunk->singleton \|\|
	136	chunk->end_of_packet \|\|
	137	chunk->pdiscard) {
	138	sctp_chunk_free(chunk);
	139	chunk = queue->in_progress = NULL;
	140	} else {
	141	/* Nothing to do. Next chunk in the packet, please. */
	142	ch = (sctp_chunkhdr_t *) chunk->chunk_end;
	143
	144	/* Force chunk->skb->data to chunk->chunk_end. */
	145	skb_pull(chunk->skb,
	146	chunk->chunk_end - chunk->skb->data);
a09c8384 VY	147
	148	/* Verify that we have at least chunk headers
	149	* worth of buffer left.
	150	*/
	151	if (skb_headlen(chunk->skb) < sizeof(sctp_chunkhdr_t)) {
	152	sctp_chunk_free(chunk);
	153	chunk = queue->in_progress = NULL;
	154	}
1da177e4 LT	155	}
	156	}
	157
	158	/* Do we need to take the next packet out of the queue to process? */
	159	if (!chunk) {
79af02c2 DM	160	struct list_head *entry;
79af02c2 DM	161
1da177e4	162	/* Is the queue empty? */
79af02c2	163	if (list_empty(&queue->in_chunk_list))
1da177e4 LT	164	return NULL;
1da177e4 LT	165
79af02c2	166	entry = queue->in_chunk_list.next;
1da177e4	167	chunk = queue->in_progress =
79af02c2 DM	168	list_entry(entry, struct sctp_chunk, list);
79af02c2 DM	169	list_del_init(entry);
1da177e4 LT	170
	171	/* This is the first chunk in the packet. */
	172	chunk->singleton = 1;
	173	ch = (sctp_chunkhdr_t *) chunk->skb->data;
7c3ceb4f	174	chunk->data_accepted = 0;
1da177e4 LT	175	}
1da177e4 LT	176
d808ad9a YH	177	chunk->chunk_hdr = ch;
d808ad9a YH	178	chunk->chunk_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
1da177e4 LT	179	/* In the unlikely case of an IP reassembly, the skb could be
	180	* non-linear. If so, update chunk_end so that it doesn't go past
	181	* the skb->tail.
	182	*/
	183	if (unlikely(skb_is_nonlinear(chunk->skb))) {
27a884dc ACM	184	if (chunk->chunk_end > skb_tail_pointer(chunk->skb))
27a884dc ACM	185	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1da177e4 LT	186	}
	187	skb_pull(chunk->skb, sizeof(sctp_chunkhdr_t));
	188	chunk->subh.v = NULL; /* Subheader is no longer valid. */
	189
27a884dc	190	if (chunk->chunk_end < skb_tail_pointer(chunk->skb)) {
1da177e4 LT	191	/* This is not a singleton */
1da177e4 LT	192	chunk->singleton = 0;
27a884dc	193	} else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
d808ad9a	194	/* RFC 2960, Section 6.10 Bundling
1da177e4 LT	195	*
	196	* Partial chunks MUST NOT be placed in an SCTP packet.
	197	* If the receiver detects a partial chunk, it MUST drop
d808ad9a	198	* the chunk.
1da177e4 LT	199	*
	200	* Since the end of the chunk is past the end of our buffer
	201	* (which contains the whole packet, we can freely discard
	202	* the whole packet.
	203	*/
	204	sctp_chunk_free(chunk);
	205	chunk = queue->in_progress = NULL;
	206
	207	return NULL;
	208	} else {
	209	/* We are at the end of the packet, so mark the chunk
	210	* in case we need to send a SACK.
	211	*/
	212	chunk->end_of_packet = 1;
	213	}
	214
bb33381d DB	215	pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n",
	216	chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),
	217	ntohs(chunk->chunk_hdr->length), chunk->skb->len);
	218
1da177e4 LT	219	return chunk;
	220	}
	221
	222	/* Set a top-half handler.
	223	*
	224	* Originally, we the top-half handler was scheduled as a BH. We now
	225	* call the handler directly in sctp_inq_push() at a time that
	226	* we know we are lock safe.
	227	* The intent is that this routine will pull stuff out of the
	228	* inqueue and process it.
	229	*/
c4028958	230	void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback)
1da177e4	231	{
c4028958	232	INIT_WORK(&q->immediate, callback);
1da177e4	233	}