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

/* SCTP kernel implementation
 * (C) Copyright IBM Corp. 2001, 2004
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2001 Intel Corp.
 *
 * This file is part of the SCTP kernel implementation
 *
 * These functions manipulate sctp tsn mapping array.
 *
 * 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 <linux-sctp@vger.kernel.org>
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *    Karl Knutson          <karl@athena.chicago.il.us>
 *    Sridhar Samudrala     <sri@us.ibm.com>
 */

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

static void sctp_tsnmap_update(struct sctp_tsnmap *map);
static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
				     __u16 len, __u16 *start, __u16 *end);
static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 size);

/* Initialize a block of memory as a tsnmap.  */
struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *map, __u16 len,
				     __u32 initial_tsn, gfp_t gfp)
{
	if (!map->tsn_map) {
		map->tsn_map = kzalloc(len>>3, gfp);
		if (map->tsn_map == NULL)
			return NULL;

		map->len = len;
	} else {
		bitmap_zero(map->tsn_map, map->len);
	}

	/* Keep track of TSNs represented by tsn_map.  */
	map->base_tsn = initial_tsn;
	map->cumulative_tsn_ack_point = initial_tsn - 1;
	map->max_tsn_seen = map->cumulative_tsn_ack_point;
	map->num_dup_tsns = 0;

	return map;
}

void sctp_tsnmap_free(struct sctp_tsnmap *map)
{
	map->len = 0;
	kfree(map->tsn_map);
}

/* Test the tracking state of this TSN.
 * Returns:
 *   0 if the TSN has not yet been seen
 *  >0 if the TSN has been seen (duplicate)
 *  <0 if the TSN is invalid (too large to track)
 */
int sctp_tsnmap_check(const struct sctp_tsnmap *map, __u32 tsn)
{
	u32 gap;

	/* Check to see if this is an old TSN */
	if (TSN_lte(tsn, map->cumulative_tsn_ack_point))
		return 1;

	/* Verify that we can hold this TSN and that it will not
	 * overlfow our map
	 */
	if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
		return -1;

	/* Calculate the index into the mapping arrays.  */
	gap = tsn - map->base_tsn;

	/* Check to see if TSN has already been recorded.  */
	if (gap < map->len && test_bit(gap, map->tsn_map))
		return 1;
	else
		return 0;
}


/* Mark this TSN as seen.  */
int sctp_tsnmap_mark(struct sctp_tsnmap *map, __u32 tsn,
		     struct sctp_transport *trans)
{
	u16 gap;

	if (TSN_lt(tsn, map->base_tsn))
		return 0;

	gap = tsn - map->base_tsn;

	if (gap >= map->len && !sctp_tsnmap_grow(map, gap + 1))
		return -ENOMEM;

	if (!sctp_tsnmap_has_gap(map) && gap == 0) {
		/* In this case the map has no gaps and the tsn we are
		 * recording is the next expected tsn.  We don't touch
		 * the map but simply bump the values.
		 */
		map->max_tsn_seen++;
		map->cumulative_tsn_ack_point++;
		if (trans)
			trans->sack_generation =
				trans->asoc->peer.sack_generation;
		map->base_tsn++;
	} else {
		/* Either we already have a gap, or about to record a gap, so
		 * have work to do.
		 *
		 * Bump the max.
		 */
		if (TSN_lt(map->max_tsn_seen, tsn))
			map->max_tsn_seen = tsn;

		/* Mark the TSN as received.  */
		set_bit(gap, map->tsn_map);

		/* Go fixup any internal TSN mapping variables including
		 * cumulative_tsn_ack_point.
		 */
		sctp_tsnmap_update(map);
	}

	return 0;
}


/* Initialize a Gap Ack Block iterator from memory being provided.  */
static void sctp_tsnmap_iter_init(const struct sctp_tsnmap *map,
				  struct sctp_tsnmap_iter *iter)
{
	/* Only start looking one past the Cumulative TSN Ack Point.  */
	iter->start = map->cumulative_tsn_ack_point + 1;
}

/* Get the next Gap Ack Blocks. Returns 0 if there was not another block
 * to get.
 */
static int sctp_tsnmap_next_gap_ack(const struct sctp_tsnmap *map,
				    struct sctp_tsnmap_iter *iter,
				    __u16 *start, __u16 *end)
{
	int ended = 0;
	__u16 start_ = 0, end_ = 0, offset;

	/* If there are no more gap acks possible, get out fast.  */
	if (TSN_lte(map->max_tsn_seen, iter->start))
		return 0;

	offset = iter->start - map->base_tsn;
	sctp_tsnmap_find_gap_ack(map->tsn_map, offset, map->len,
				 &start_, &end_);

	/* The Gap Ack Block happens to end at the end of the map. */
	if (start_ && !end_)
		end_ = map->len - 1;

	/* If we found a Gap Ack Block, return the start and end and
	 * bump the iterator forward.
	 */
	if (end_) {
		/* Fix up the start and end based on the
		 * Cumulative TSN Ack which is always 1 behind base.
		 */
		*start = start_ + 1;
		*end = end_ + 1;

		/* Move the iterator forward.  */
		iter->start = map->cumulative_tsn_ack_point + *end + 1;
		ended = 1;
	}

	return ended;
}

/* Mark this and any lower TSN as seen.  */
void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn)
{
	u32 gap;

	if (TSN_lt(tsn, map->base_tsn))
		return;
	if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
		return;

	/* Bump the max.  */
	if (TSN_lt(map->max_tsn_seen, tsn))
		map->max_tsn_seen = tsn;

	gap = tsn - map->base_tsn + 1;

	map->base_tsn += gap;
	map->cumulative_tsn_ack_point += gap;
	if (gap >= map->len) {
		/* If our gap is larger then the map size, just
		 * zero out the map.
		 */
		bitmap_zero(map->tsn_map, map->len);
	} else {
		/* If the gap is smaller than the map size,
		 * shift the map by 'gap' bits and update further.
		 */
		bitmap_shift_right(map->tsn_map, map->tsn_map, gap, map->len);
		sctp_tsnmap_update(map);
	}
}

/********************************************************************
 * 2nd Level Abstractions
 ********************************************************************/

/* This private helper function updates the tsnmap buffers and
 * the Cumulative TSN Ack Point.
 */
static void sctp_tsnmap_update(struct sctp_tsnmap *map)
{
	u16 len;
	unsigned long zero_bit;


	len = map->max_tsn_seen - map->cumulative_tsn_ack_point;
	zero_bit = find_first_zero_bit(map->tsn_map, len);
	if (!zero_bit)
		return;		/* The first 0-bit is bit 0.  nothing to do */

	map->base_tsn += zero_bit;
	map->cumulative_tsn_ack_point += zero_bit;

	bitmap_shift_right(map->tsn_map, map->tsn_map, zero_bit, map->len);
}

/* How many data chunks  are we missing from our peer?
 */
__u16 sctp_tsnmap_pending(struct sctp_tsnmap *map)
{
	__u32 cum_tsn = map->cumulative_tsn_ack_point;
	__u32 max_tsn = map->max_tsn_seen;
	__u32 base_tsn = map->base_tsn;
	__u16 pending_data;
	u32 gap;

	pending_data = max_tsn - cum_tsn;
	gap = max_tsn - base_tsn;

	if (gap == 0 || gap >= map->len)
		goto out;

	pending_data -= bitmap_weight(map->tsn_map, gap + 1);
out:
	return pending_data;
}

/* This is a private helper for finding Gap Ack Blocks.  It searches a
 * single array for the start and end of a Gap Ack Block.
 *
 * The flags "started" and "ended" tell is if we found the beginning
 * or (respectively) the end of a Gap Ack Block.
 */
static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
				     __u16 len, __u16 *start, __u16 *end)
{
	int i = off;

	/* Look through the entire array, but break out
	 * early if we have found the end of the Gap Ack Block.
	 */

	/* Also, stop looking past the maximum TSN seen. */

	/* Look for the start. */
	i = find_next_bit(map, len, off);
	if (i < len)
		*start = i;

	/* Look for the end.  */
	if (*start) {
		/* We have found the start, let's find the
		 * end.  If we find the end, break out.
		 */
		i = find_next_zero_bit(map, len, i);
		if (i < len)
			*end = i - 1;
	}
}

/* Renege that we have seen a TSN.  */
void sctp_tsnmap_renege(struct sctp_tsnmap *map, __u32 tsn)
{
	u32 gap;

	if (TSN_lt(tsn, map->base_tsn))
		return;
	/* Assert: TSN is in range.  */
	if (!TSN_lt(tsn, map->base_tsn + map->len))
		return;

	gap = tsn - map->base_tsn;

	/* Pretend we never saw the TSN.  */
	clear_bit(gap, map->tsn_map);
}

/* How many gap ack blocks do we have recorded? */
__u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
			   struct sctp_gap_ack_block *gabs)
{
	struct sctp_tsnmap_iter iter;
	int ngaps = 0;

	/* Refresh the gap ack information. */
	if (sctp_tsnmap_has_gap(map)) {
		__u16 start = 0, end = 0;
		sctp_tsnmap_iter_init(map, &iter);
		while (sctp_tsnmap_next_gap_ack(map, &iter,
						&start,
						&end)) {

			gabs[ngaps].start = htons(start);
			gabs[ngaps].end = htons(end);
			ngaps++;
			if (ngaps >= SCTP_MAX_GABS)
				break;
		}
	}
	return ngaps;
}

static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 size)
{
	unsigned long *new;
	unsigned long inc;
	u16  len;

	if (size > SCTP_TSN_MAP_SIZE)
		return 0;

	inc = ALIGN((size - map->len), BITS_PER_LONG) + SCTP_TSN_MAP_INCREMENT;
	len = min_t(u16, map->len + inc, SCTP_TSN_MAP_SIZE);

	new = kzalloc(len>>3, GFP_ATOMIC);
	if (!new)
		return 0;

	bitmap_copy(new, map->tsn_map,
		map->max_tsn_seen - map->cumulative_tsn_ack_point);
	kfree(map->tsn_map);
	map->tsn_map = new;
	map->len = len;

	return 1;
}
Commit	Line	Data
60c778b2	1	/* SCTP kernel implementation
1da177e4 LT	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	*
60c778b2	7	* This file is part of the SCTP kernel implementation
1da177e4 LT	8	*
	9	* These functions manipulate sctp tsn mapping array.
	10	*
60c778b2	11	* This SCTP implementation is free software;
1da177e4 LT	12	* you can redistribute it and/or modify it under the terms of
	13	* the GNU General Public License as published by
	14	* the Free Software Foundation; either version 2, or (at your option)
	15	* any later version.
	16	*
60c778b2	17	* This SCTP implementation is distributed in the hope that it
1da177e4 LT	18	* will be useful, but WITHOUT ANY WARRANTY; without even the implied
	19	* ************************
	20	* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
	21	* See the GNU General Public License for more details.
	22	*
	23	* You should have received a copy of the GNU General Public License
	24	* along with GNU CC; see the file COPYING. If not, write to
	25	* the Free Software Foundation, 59 Temple Place - Suite 330,
	26	* Boston, MA 02111-1307, USA.
	27	*
	28	* Please send any bug reports or fixes you make to the
	29	* email address(es):
91705c61	30	* lksctp developers <linux-sctp@vger.kernel.org>
1da177e4	31	*
1da177e4 LT	32	* Written or modified by:
	33	* La Monte H.P. Yarroll <piggy@acm.org>
	34	* Jon Grimm <jgrimm@us.ibm.com>
	35	* Karl Knutson <karl@athena.chicago.il.us>
	36	* Sridhar Samudrala <sri@us.ibm.com>
1da177e4 LT	37	*/
1da177e4 LT	38
5a0e3ad6	39	#include <linux/slab.h>
1da177e4	40	#include <linux/types.h>
8e1ee18c	41	#include <linux/bitmap.h>
1da177e4 LT	42	#include <net/sctp/sctp.h>
	43	#include <net/sctp/sm.h>
	44
	45	static void sctp_tsnmap_update(struct sctp_tsnmap *map);
8e1ee18c VY	46	static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
8e1ee18c VY	47	__u16 len, __u16 start, __u16 end);
70fc69bc	48	static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 size);
1da177e4 LT	49
	50	/* Initialize a block of memory as a tsnmap. */
	51	struct sctp_tsnmap sctp_tsnmap_init(struct sctp_tsnmap map, __u16 len,
8e1ee18c	52	__u32 initial_tsn, gfp_t gfp)
1da177e4	53	{
8e1ee18c VY	54	if (!map->tsn_map) {
	55	map->tsn_map = kzalloc(len>>3, gfp);
	56	if (map->tsn_map == NULL)
	57	return NULL;
	58
	59	map->len = len;
	60	} else {
	61	bitmap_zero(map->tsn_map, map->len);
	62	}
1da177e4 LT	63
	64	/* Keep track of TSNs represented by tsn_map. */
	65	map->base_tsn = initial_tsn;
1da177e4 LT	66	map->cumulative_tsn_ack_point = initial_tsn - 1;
1da177e4 LT	67	map->max_tsn_seen = map->cumulative_tsn_ack_point;
1da177e4 LT	68	map->num_dup_tsns = 0;
	69
	70	return map;
	71	}
	72
8e1ee18c VY	73	void sctp_tsnmap_free(struct sctp_tsnmap *map)
	74	{
	75	map->len = 0;
	76	kfree(map->tsn_map);
	77	}
	78
1da177e4 LT	79	/* Test the tracking state of this TSN.
	80	* Returns:
	81	* 0 if the TSN has not yet been seen
	82	* >0 if the TSN has been seen (duplicate)
	83	* <0 if the TSN is invalid (too large to track)
	84	*/
	85	int sctp_tsnmap_check(const struct sctp_tsnmap *map, __u32 tsn)
	86	{
8e1ee18c VY	87	u32 gap;
	88
	89	/* Check to see if this is an old TSN */
	90	if (TSN_lte(tsn, map->cumulative_tsn_ack_point))
	91	return 1;
	92
	93	/* Verify that we can hold this TSN and that it will not
	94	* overlfow our map
	95	*/
	96	if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
	97	return -1;
1da177e4 LT	98
	99	/* Calculate the index into the mapping arrays. */
	100	gap = tsn - map->base_tsn;
	101
8e1ee18c VY	102	/* Check to see if TSN has already been recorded. */
	103	if (gap < map->len && test_bit(gap, map->tsn_map))
	104	return 1;
1da177e4	105	else
8e1ee18c	106	return 0;
1da177e4 LT	107	}
	108
	109
	110	/* Mark this TSN as seen. */
4244854d NH	111	int sctp_tsnmap_mark(struct sctp_tsnmap *map, __u32 tsn,
4244854d NH	112	struct sctp_transport *trans)
1da177e4	113	{
8e1ee18c	114	u16 gap;
1da177e4	115
1da177e4	116	if (TSN_lt(tsn, map->base_tsn))
8e1ee18c	117	return 0;
1da177e4	118
1da177e4 LT	119	gap = tsn - map->base_tsn;
1da177e4 LT	120
70fc69bc	121	if (gap >= map->len && !sctp_tsnmap_grow(map, gap + 1))
8e1ee18c	122	return -ENOMEM;
1da177e4	123
8e1ee18c VY	124	if (!sctp_tsnmap_has_gap(map) && gap == 0) {
	125	/* In this case the map has no gaps and the tsn we are
	126	* recording is the next expected tsn. We don't touch
	127	* the map but simply bump the values.
	128	*/
	129	map->max_tsn_seen++;
	130	map->cumulative_tsn_ack_point++;
4244854d NH	131	if (trans)
	132	trans->sack_generation =
	133	trans->asoc->peer.sack_generation;
8e1ee18c VY	134	map->base_tsn++;
	135	} else {
	136	/* Either we already have a gap, or about to record a gap, so
	137	* have work to do.
	138	*
	139	* Bump the max.
	140	*/
	141	if (TSN_lt(map->max_tsn_seen, tsn))
	142	map->max_tsn_seen = tsn;
	143
	144	/* Mark the TSN as received. */
	145	set_bit(gap, map->tsn_map);
	146
	147	/* Go fixup any internal TSN mapping variables including
	148	* cumulative_tsn_ack_point.
	149	*/
	150	sctp_tsnmap_update(map);
	151	}
	152
	153	return 0;
1da177e4 LT	154	}
	155
	156
	157	/* Initialize a Gap Ack Block iterator from memory being provided. */
dda91928 DB	158	static void sctp_tsnmap_iter_init(const struct sctp_tsnmap *map,
dda91928 DB	159	struct sctp_tsnmap_iter *iter)
1da177e4 LT	160	{
	161	/* Only start looking one past the Cumulative TSN Ack Point. */
	162	iter->start = map->cumulative_tsn_ack_point + 1;
	163	}
	164
	165	/* Get the next Gap Ack Blocks. Returns 0 if there was not another block
	166	* to get.
	167	*/
dda91928 DB	168	static int sctp_tsnmap_next_gap_ack(const struct sctp_tsnmap *map,
	169	struct sctp_tsnmap_iter *iter,
	170	__u16 start, __u16 end)
1da177e4	171	{
8e1ee18c VY	172	int ended = 0;
8e1ee18c VY	173	__u16 start_ = 0, end_ = 0, offset;
1da177e4 LT	174
	175	/* If there are no more gap acks possible, get out fast. */
	176	if (TSN_lte(map->max_tsn_seen, iter->start))
	177	return 0;
	178
8e1ee18c VY	179	offset = iter->start - map->base_tsn;
	180	sctp_tsnmap_find_gap_ack(map->tsn_map, offset, map->len,
	181	&start_, &end_);
1da177e4	182
8e1ee18c VY	183	/* The Gap Ack Block happens to end at the end of the map. */
	184	if (start_ && !end_)
	185	end_ = map->len - 1;
1da177e4 LT	186
	187	/* If we found a Gap Ack Block, return the start and end and
	188	* bump the iterator forward.
	189	*/
8e1ee18c	190	if (end_) {
1da177e4	191	/* Fix up the start and end based on the
8e1ee18c	192	* Cumulative TSN Ack which is always 1 behind base.
1da177e4	193	*/
8e1ee18c VY	194	*start = start_ + 1;
8e1ee18c VY	195	*end = end_ + 1;
1da177e4 LT	196
	197	/* Move the iterator forward. */
	198	iter->start = map->cumulative_tsn_ack_point + *end + 1;
8e1ee18c	199	ended = 1;
1da177e4 LT	200	}
	201
	202	return ended;
	203	}
	204
	205	/* Mark this and any lower TSN as seen. */
	206	void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn)
	207	{
8e1ee18c	208	u32 gap;
1da177e4	209
1da177e4 LT	210	if (TSN_lt(tsn, map->base_tsn))
1da177e4 LT	211	return;
8e1ee18c	212	if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
1da177e4 LT	213	return;
	214
	215	/* Bump the max. */
	216	if (TSN_lt(map->max_tsn_seen, tsn))
	217	map->max_tsn_seen = tsn;
	218
1da177e4 LT	219	gap = tsn - map->base_tsn + 1;
1da177e4 LT	220
8e1ee18c VY	221	map->base_tsn += gap;
	222	map->cumulative_tsn_ack_point += gap;
	223	if (gap >= map->len) {
	224	/* If our gap is larger then the map size, just
	225	* zero out the map.
	226	*/
	227	bitmap_zero(map->tsn_map, map->len);
	228	} else {
025dfdaf	229	/* If the gap is smaller than the map size,
8e1ee18c VY	230	* shift the map by 'gap' bits and update further.
	231	*/
	232	bitmap_shift_right(map->tsn_map, map->tsn_map, gap, map->len);
	233	sctp_tsnmap_update(map);
1da177e4	234	}
1da177e4 LT	235	}
	236
	237	/********************************************************************
	238	* 2nd Level Abstractions
	239	********************************************************************/
	240
	241	/* This private helper function updates the tsnmap buffers and
	242	* the Cumulative TSN Ack Point.
	243	*/
	244	static void sctp_tsnmap_update(struct sctp_tsnmap *map)
	245	{
8e1ee18c VY	246	u16 len;
	247	unsigned long zero_bit;
	248
	249
	250	len = map->max_tsn_seen - map->cumulative_tsn_ack_point;
	251	zero_bit = find_first_zero_bit(map->tsn_map, len);
	252	if (!zero_bit)
	253	return; /* The first 0-bit is bit 0. nothing to do */
	254
	255	map->base_tsn += zero_bit;
	256	map->cumulative_tsn_ack_point += zero_bit;
1da177e4	257
8e1ee18c	258	bitmap_shift_right(map->tsn_map, map->tsn_map, zero_bit, map->len);
1da177e4 LT	259	}
	260
	261	/* How many data chunks are we missing from our peer?
	262	*/
	263	__u16 sctp_tsnmap_pending(struct sctp_tsnmap *map)
	264	{
	265	__u32 cum_tsn = map->cumulative_tsn_ack_point;
	266	__u32 max_tsn = map->max_tsn_seen;
	267	__u32 base_tsn = map->base_tsn;
	268	__u16 pending_data;
fc184f08	269	u32 gap;
1da177e4 LT	270
	271	pending_data = max_tsn - cum_tsn;
	272	gap = max_tsn - base_tsn;
	273
8e1ee18c	274	if (gap == 0 \|\| gap >= map->len)
1da177e4 LT	275	goto out;
1da177e4 LT	276
fc184f08	277	pending_data -= bitmap_weight(map->tsn_map, gap + 1);
1da177e4 LT	278	out:
	279	return pending_data;
	280	}
	281
	282	/* This is a private helper for finding Gap Ack Blocks. It searches a
	283	* single array for the start and end of a Gap Ack Block.
	284	*
	285	* The flags "started" and "ended" tell is if we found the beginning
	286	* or (respectively) the end of a Gap Ack Block.
	287	*/
8e1ee18c VY	288	static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
8e1ee18c VY	289	__u16 len, __u16 start, __u16 end)
1da177e4 LT	290	{
	291	int i = off;
	292
	293	/* Look through the entire array, but break out
	294	* early if we have found the end of the Gap Ack Block.
	295	*/
	296
	297	/* Also, stop looking past the maximum TSN seen. */
	298
	299	/* Look for the start. */
8e1ee18c VY	300	i = find_next_bit(map, len, off);
	301	if (i < len)
	302	*start = i;
1da177e4 LT	303
1da177e4 LT	304	/* Look for the end. */
8e1ee18c	305	if (*start) {
1da177e4 LT	306	/* We have found the start, let's find the
	307	* end. If we find the end, break out.
	308	*/
8e1ee18c VY	309	i = find_next_zero_bit(map, len, i);
	310	if (i < len)
	311	*end = i - 1;
1da177e4 LT	312	}
	313	}
	314
	315	/* Renege that we have seen a TSN. */
	316	void sctp_tsnmap_renege(struct sctp_tsnmap *map, __u32 tsn)
	317	{
8e1ee18c	318	u32 gap;
1da177e4 LT	319
	320	if (TSN_lt(tsn, map->base_tsn))
	321	return;
8e1ee18c VY	322	/* Assert: TSN is in range. */
8e1ee18c VY	323	if (!TSN_lt(tsn, map->base_tsn + map->len))
1da177e4 LT	324	return;
1da177e4 LT	325
1da177e4 LT	326	gap = tsn - map->base_tsn;
	327
	328	/* Pretend we never saw the TSN. */
8e1ee18c	329	clear_bit(gap, map->tsn_map);
1da177e4 LT	330	}
	331
	332	/* How many gap ack blocks do we have recorded? */
02015180 VY	333	__u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
02015180 VY	334	struct sctp_gap_ack_block *gabs)
1da177e4 LT	335	{
1da177e4 LT	336	struct sctp_tsnmap_iter iter;
02015180	337	int ngaps = 0;
1da177e4 LT	338
	339	/* Refresh the gap ack information. */
	340	if (sctp_tsnmap_has_gap(map)) {
59ed5aba	341	__u16 start = 0, end = 0;
1da177e4 LT	342	sctp_tsnmap_iter_init(map, &iter);
1da177e4 LT	343	while (sctp_tsnmap_next_gap_ack(map, &iter,
9f81bcd9 AV	344	&start,
9f81bcd9 AV	345	&end)) {
1da177e4	346
02015180 VY	347	gabs[ngaps].start = htons(start);
	348	gabs[ngaps].end = htons(end);
	349	ngaps++;
	350	if (ngaps >= SCTP_MAX_GABS)
1da177e4 LT	351	break;
	352	}
	353	}
02015180	354	return ngaps;
1da177e4	355	}
8e1ee18c	356
70fc69bc	357	static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 size)
8e1ee18c VY	358	{
	359	unsigned long *new;
	360	unsigned long inc;
	361	u16 len;
	362
70fc69bc	363	if (size > SCTP_TSN_MAP_SIZE)
8e1ee18c VY	364	return 0;
8e1ee18c VY	365
70fc69bc	366	inc = ALIGN((size - map->len), BITS_PER_LONG) + SCTP_TSN_MAP_INCREMENT;
8e1ee18c VY	367	len = min_t(u16, map->len + inc, SCTP_TSN_MAP_SIZE);
	368
	369	new = kzalloc(len>>3, GFP_ATOMIC);
	370	if (!new)
	371	return 0;
	372
70fc69bc LR	373	bitmap_copy(new, map->tsn_map,
70fc69bc LR	374	map->max_tsn_seen - map->cumulative_tsn_ack_point);
8e1ee18c VY	375	kfree(map->tsn_map);
	376	map->tsn_map = new;
	377	map->len = len;
	378
	379	return 1;
	380	}