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

// SPDX-License-Identifier: GPL-2.0-or-later
/* 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.
 *
 * 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;
	struct sctp_chunkhdr *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 = (struct sctp_chunkhdr *)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;
	struct sctp_chunkhdr *ch = NULL;

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

	chunk = queue->in_progress;
	if (chunk) {
		/* 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) {
			if (chunk->head_skb == chunk->skb) {
				chunk->skb = skb_shinfo(chunk->skb)->frag_list;
				goto new_skb;
			}
			if (chunk->skb->next) {
				chunk->skb = chunk->skb->next;
				goto new_skb;
			}

			if (chunk->head_skb)
				chunk->skb = chunk->head_skb;
			sctp_chunk_free(chunk);
			chunk = queue->in_progress = NULL;
		} else {
			/* Nothing to do. Next chunk in the packet, please. */
			ch = (struct sctp_chunkhdr *)chunk->chunk_end;
			/* Force chunk->skb->data to chunk->chunk_end.  */
			skb_pull(chunk->skb, chunk->chunk_end - chunk->skb->data);
			/* We are guaranteed to pull a SCTP header. */
		}
	}

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

next_chunk:
		/* Is the queue empty?  */
		entry = sctp_list_dequeue(&queue->in_chunk_list);
		if (!entry)
			return NULL;

		chunk = list_entry(entry, struct sctp_chunk, list);

		if (skb_is_gso(chunk->skb) && skb_is_gso_sctp(chunk->skb)) {
			/* GSO-marked skbs but without frags, handle
			 * them normally
			 */
			if (skb_shinfo(chunk->skb)->frag_list)
				chunk->head_skb = chunk->skb;

			/* skbs with "cover letter" */
			if (chunk->head_skb && chunk->skb->data_len == chunk->skb->len)
				chunk->skb = skb_shinfo(chunk->skb)->frag_list;

			if (WARN_ON(!chunk->skb)) {
				__SCTP_INC_STATS(dev_net(chunk->skb->dev), SCTP_MIB_IN_PKT_DISCARDS);
				sctp_chunk_free(chunk);
				goto next_chunk;
			}
		}

		if (chunk->asoc)
			sock_rps_save_rxhash(chunk->asoc->base.sk, chunk->skb);

		queue->in_progress = chunk;

new_skb:
		/* This is the first chunk in the packet.  */
		ch = (struct sctp_chunkhdr *)chunk->skb->data;
		chunk->singleton = 1;
		chunk->data_accepted = 0;
		chunk->pdiscard = 0;
		chunk->auth = 0;
		chunk->has_asconf = 0;
		chunk->end_of_packet = 0;
		if (chunk->head_skb) {
			struct sctp_input_cb
				*cb = SCTP_INPUT_CB(chunk->skb),
				*head_cb = SCTP_INPUT_CB(chunk->head_skb);

			cb->chunk = head_cb->chunk;
			cb->af = head_cb->af;
		}
	}

	chunk->chunk_hdr = ch;
	chunk->chunk_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
	skb_pull(chunk->skb, sizeof(*ch));
	chunk->subh.v = NULL; /* Subheader is no longer valid.  */

	if (chunk->chunk_end + sizeof(*ch) <= skb_tail_pointer(chunk->skb)) {
		/* This is not a singleton */
		chunk->singleton = 0;
	} else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
		/* Discard inside state machine. */
		chunk->pdiscard = 1;
		chunk->chunk_end = skb_tail_pointer(chunk->skb);
	} 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
47505b8b	1	// SPDX-License-Identifier: GPL-2.0-or-later
60c778b2	2	/* SCTP kernel implementation
1da177e4 LT	3	* Copyright (c) 1999-2000 Cisco, Inc.
	4	* Copyright (c) 1999-2001 Motorola, Inc.
	5	* Copyright (c) 2002 International Business Machines, Corp.
d808ad9a	6	*
60c778b2	7	* This file is part of the SCTP kernel implementation
d808ad9a	8	*
1da177e4 LT	9	* These functions are the methods for accessing the SCTP inqueue.
	10	*
	11	* An SCTP inqueue is a queue into which you push SCTP packets
	12	* (which might be bundles or fragments of chunks) and out of which you
	13	* pop SCTP whole chunks.
d808ad9a	14	*
1da177e4 LT	15	* Please send any bug reports or fixes you make to the
1da177e4 LT	16	* email address(es):
91705c61	17	* lksctp developers <linux-sctp@vger.kernel.org>
d808ad9a	18	*
d808ad9a	19	* Written or modified by:
1da177e4 LT	20	* La Monte H.P. Yarroll <piggy@acm.org>
1da177e4 LT	21	* Karl Knutson <karl@athena.chicago.il.us>
1da177e4 LT	22	*/
1da177e4 LT	23
145ce502 JP	24	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
145ce502 JP	25
1da177e4 LT	26	#include <net/sctp/sctp.h>
	27	#include <net/sctp/sm.h>
	28	#include <linux/interrupt.h>
5a0e3ad6	29	#include <linux/slab.h>
1da177e4 LT	30
	31	/* Initialize an SCTP inqueue. */
	32	void sctp_inq_init(struct sctp_inq *queue)
	33	{
79af02c2	34	INIT_LIST_HEAD(&queue->in_chunk_list);
1da177e4 LT	35	queue->in_progress = NULL;
	36
	37	/* Create a task for delivering data. */
c4028958	38	INIT_WORK(&queue->immediate, NULL);
1da177e4 LT	39	}
	40
	41	/* Release the memory associated with an SCTP inqueue. */
	42	void sctp_inq_free(struct sctp_inq *queue)
	43	{
79af02c2	44	struct sctp_chunk chunk, tmp;
1da177e4 LT	45
1da177e4 LT	46	/* Empty the queue. */
79af02c2 DM	47	list_for_each_entry_safe(chunk, tmp, &queue->in_chunk_list, list) {
79af02c2 DM	48	list_del_init(&chunk->list);
1da177e4	49	sctp_chunk_free(chunk);
79af02c2	50	}
1da177e4 LT	51
	52	/* If there is a packet which is currently being worked on,
	53	* free it as well.
	54	*/
7a48f923	55	if (queue->in_progress) {
1da177e4	56	sctp_chunk_free(queue->in_progress);
7a48f923 SS	57	queue->in_progress = NULL;
7a48f923 SS	58	}
1da177e4 LT	59	}
	60
	61	/* Put a new packet in an SCTP inqueue.
	62	* We assume that packet->sctp_hdr is set and in host byte order.
	63	*/
ac0b0462	64	void sctp_inq_push(struct sctp_inq q, struct sctp_chunk chunk)
1da177e4 LT	65	{
1da177e4 LT	66	/* Directly call the packet handling routine. */
027f6e1a VY	67	if (chunk->rcvr->dead) {
	68	sctp_chunk_free(chunk);
	69	return;
	70	}
1da177e4 LT	71
	72	/* We are now calling this either from the soft interrupt
	73	* or from the backlog processing.
	74	* Eventually, we should clean up inqueue to not rely
	75	* on the BH related data structures.
	76	*/
ac0b0462	77	list_add_tail(&chunk->list, &q->in_chunk_list);
196d6759 MB	78	if (chunk->asoc)
196d6759 MB	79	chunk->asoc->stats.ipackets++;
c4028958	80	q->immediate.func(&q->immediate);
1da177e4 LT	81	}
1da177e4 LT	82
bbd0d598 VY	83	/* Peek at the next chunk on the inqeue. */
	84	struct sctp_chunkhdr sctp_inq_peek(struct sctp_inq queue)
	85	{
	86	struct sctp_chunk *chunk;
922dbc5b	87	struct sctp_chunkhdr *ch = NULL;
bbd0d598 VY	88
	89	chunk = queue->in_progress;
	90	/* If there is no more chunks in this packet, say so */
	91	if (chunk->singleton \|\|
	92	chunk->end_of_packet \|\|
	93	chunk->pdiscard)
	94	return NULL;
	95
922dbc5b	96	ch = (struct sctp_chunkhdr *)chunk->chunk_end;
bbd0d598 VY	97
	98	return ch;
	99	}
	100
	101
1da177e4 LT	102	/* Extract a chunk from an SCTP inqueue.
	103	*
	104	* WARNING: If you need to put the chunk on another queue, you need to
	105	* make a shallow copy (clone) of it.
	106	*/
	107	struct sctp_chunk sctp_inq_pop(struct sctp_inq queue)
	108	{
	109	struct sctp_chunk *chunk;
922dbc5b	110	struct sctp_chunkhdr *ch = NULL;
1da177e4 LT	111
	112	/* The assumption is that we are safe to process the chunks
	113	* at this time.
	114	*/
	115
3acb50c1 MRL	116	chunk = queue->in_progress;
3acb50c1 MRL	117	if (chunk) {
1da177e4 LT	118	/* There is a packet that we have been working on.
	119	* Any post processing work to do before we move on?
	120	*/
	121	if (chunk->singleton \|\|
	122	chunk->end_of_packet \|\|
	123	chunk->pdiscard) {
90017acc MRL	124	if (chunk->head_skb == chunk->skb) {
	125	chunk->skb = skb_shinfo(chunk->skb)->frag_list;
	126	goto new_skb;
	127	}
	128	if (chunk->skb->next) {
	129	chunk->skb = chunk->skb->next;
	130	goto new_skb;
	131	}
	132
	133	if (chunk->head_skb)
	134	chunk->skb = chunk->head_skb;
1da177e4 LT	135	sctp_chunk_free(chunk);
	136	chunk = queue->in_progress = NULL;
	137	} else {
	138	/* Nothing to do. Next chunk in the packet, please. */
922dbc5b	139	ch = (struct sctp_chunkhdr *)chunk->chunk_end;
1da177e4	140	/* Force chunk->skb->data to chunk->chunk_end. */
26b87c78 DB	141	skb_pull(chunk->skb, chunk->chunk_end - chunk->skb->data);
26b87c78 DB	142	/* We are guaranteed to pull a SCTP header. */
1da177e4 LT	143	}
	144	}
	145
	146	/* Do we need to take the next packet out of the queue to process? */
	147	if (!chunk) {
79af02c2 DM	148	struct list_head *entry;
79af02c2 DM	149
3acb50c1	150	next_chunk:
1da177e4	151	/* Is the queue empty? */
90017acc MRL	152	entry = sctp_list_dequeue(&queue->in_chunk_list);
90017acc MRL	153	if (!entry)
1da177e4 LT	154	return NULL;
1da177e4 LT	155
3acb50c1	156	chunk = list_entry(entry, struct sctp_chunk, list);
1da177e4	157
1dd27cde	158	if (skb_is_gso(chunk->skb) && skb_is_gso_sctp(chunk->skb)) {
90017acc MRL	159	/* GSO-marked skbs but without frags, handle
	160	* them normally
	161	*/
	162	if (skb_shinfo(chunk->skb)->frag_list)
	163	chunk->head_skb = chunk->skb;
	164
	165	/* skbs with "cover letter" */
	166	if (chunk->head_skb && chunk->skb->data_len == chunk->skb->len)
	167	chunk->skb = skb_shinfo(chunk->skb)->frag_list;
	168
	169	if (WARN_ON(!chunk->skb)) {
	170	__SCTP_INC_STATS(dev_net(chunk->skb->dev), SCTP_MIB_IN_PKT_DISCARDS);
	171	sctp_chunk_free(chunk);
	172	goto next_chunk;
	173	}
	174	}
	175
	176	if (chunk->asoc)
	177	sock_rps_save_rxhash(chunk->asoc->base.sk, chunk->skb);
	178
3acb50c1 MRL	179	queue->in_progress = chunk;
3acb50c1 MRL	180
90017acc	181	new_skb:
1da177e4	182	/* This is the first chunk in the packet. */
922dbc5b	183	ch = (struct sctp_chunkhdr *)chunk->skb->data;
90017acc	184	chunk->singleton = 1;
7c3ceb4f	185	chunk->data_accepted = 0;
90017acc MRL	186	chunk->pdiscard = 0;
	187	chunk->auth = 0;
	188	chunk->has_asconf = 0;
	189	chunk->end_of_packet = 0;
1f45f78f MRL	190	if (chunk->head_skb) {
	191	struct sctp_input_cb
	192	*cb = SCTP_INPUT_CB(chunk->skb),
	193	*head_cb = SCTP_INPUT_CB(chunk->head_skb);
	194
	195	cb->chunk = head_cb->chunk;
e7487c86	196	cb->af = head_cb->af;
1f45f78f	197	}
1da177e4 LT	198	}
1da177e4 LT	199
d808ad9a	200	chunk->chunk_hdr = ch;
e2f036a9	201	chunk->chunk_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
922dbc5b	202	skb_pull(chunk->skb, sizeof(*ch));
1da177e4 LT	203	chunk->subh.v = NULL; /* Subheader is no longer valid. */
1da177e4 LT	204
ce402f04	205	if (chunk->chunk_end + sizeof(*ch) <= skb_tail_pointer(chunk->skb)) {
1da177e4 LT	206	/* This is not a singleton */
1da177e4 LT	207	chunk->singleton = 0;
27a884dc	208	} else if (chunk->chunk_end > skb_tail_pointer(chunk->skb)) {
26b87c78 DB	209	/* Discard inside state machine. */
	210	chunk->pdiscard = 1;
	211	chunk->chunk_end = skb_tail_pointer(chunk->skb);
1da177e4 LT	212	} else {
	213	/* We are at the end of the packet, so mark the chunk
	214	* in case we need to send a SACK.
	215	*/
	216	chunk->end_of_packet = 1;
	217	}
	218
bb33381d DB	219	pr_debug("+++sctp_inq_pop+++ chunk:%p[%s], length:%d, skb->len:%d\n",
	220	chunk, sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)),
	221	ntohs(chunk->chunk_hdr->length), chunk->skb->len);
	222
1da177e4 LT	223	return chunk;
	224	}
	225
	226	/* Set a top-half handler.
	227	*
	228	* Originally, we the top-half handler was scheduled as a BH. We now
	229	* call the handler directly in sctp_inq_push() at a time that
	230	* we know we are lock safe.
	231	* The intent is that this routine will pull stuff out of the
	232	* inqueue and process it.
	233	*/
c4028958	234	void sctp_inq_set_th_handler(struct sctp_inq *q, work_func_t callback)
1da177e4	235	{
c4028958	236	INIT_WORK(&q->immediate, callback);
1da177e4	237	}