[mirror_ubuntu-artful-kernel.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, 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>
 *    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
4b2f13a2 JK	24	* along with GNU CC; see the file COPYING. If not, see
4b2f13a2 JK	25	* <http://www.gnu.org/licenses/>.
1da177e4 LT	26	*
	27	* Please send any bug reports or fixes you make to the
	28	* email address(es):
91705c61	29	* lksctp developers <linux-sctp@vger.kernel.org>
1da177e4	30	*
1da177e4 LT	31	* Written or modified by:
	32	* La Monte H.P. Yarroll <piggy@acm.org>
	33	* Jon Grimm <jgrimm@us.ibm.com>
	34	* Karl Knutson <karl@athena.chicago.il.us>
	35	* Sridhar Samudrala <sri@us.ibm.com>
1da177e4 LT	36	*/
1da177e4 LT	37
5a0e3ad6	38	#include <linux/slab.h>
1da177e4	39	#include <linux/types.h>
8e1ee18c	40	#include <linux/bitmap.h>
1da177e4 LT	41	#include <net/sctp/sctp.h>
	42	#include <net/sctp/sm.h>
	43
	44	static void sctp_tsnmap_update(struct sctp_tsnmap *map);
8e1ee18c VY	45	static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
8e1ee18c VY	46	__u16 len, __u16 start, __u16 end);
70fc69bc	47	static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 size);
1da177e4 LT	48
	49	/* Initialize a block of memory as a tsnmap. */
	50	struct sctp_tsnmap sctp_tsnmap_init(struct sctp_tsnmap map, __u16 len,
8e1ee18c	51	__u32 initial_tsn, gfp_t gfp)
1da177e4	52	{
8e1ee18c VY	53	if (!map->tsn_map) {
	54	map->tsn_map = kzalloc(len>>3, gfp);
	55	if (map->tsn_map == NULL)
	56	return NULL;
	57
	58	map->len = len;
	59	} else {
	60	bitmap_zero(map->tsn_map, map->len);
	61	}
1da177e4 LT	62
	63	/* Keep track of TSNs represented by tsn_map. */
	64	map->base_tsn = initial_tsn;
1da177e4 LT	65	map->cumulative_tsn_ack_point = initial_tsn - 1;
1da177e4 LT	66	map->max_tsn_seen = map->cumulative_tsn_ack_point;
1da177e4 LT	67	map->num_dup_tsns = 0;
	68
	69	return map;
	70	}
	71
8e1ee18c VY	72	void sctp_tsnmap_free(struct sctp_tsnmap *map)
	73	{
	74	map->len = 0;
	75	kfree(map->tsn_map);
	76	}
	77
1da177e4 LT	78	/* Test the tracking state of this TSN.
	79	* Returns:
	80	* 0 if the TSN has not yet been seen
	81	* >0 if the TSN has been seen (duplicate)
	82	* <0 if the TSN is invalid (too large to track)
	83	*/
	84	int sctp_tsnmap_check(const struct sctp_tsnmap *map, __u32 tsn)
	85	{
8e1ee18c VY	86	u32 gap;
	87
	88	/* Check to see if this is an old TSN */
	89	if (TSN_lte(tsn, map->cumulative_tsn_ack_point))
	90	return 1;
	91
	92	/* Verify that we can hold this TSN and that it will not
	93	* overlfow our map
	94	*/
	95	if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
	96	return -1;
1da177e4 LT	97
	98	/* Calculate the index into the mapping arrays. */
	99	gap = tsn - map->base_tsn;
	100
8e1ee18c VY	101	/* Check to see if TSN has already been recorded. */
	102	if (gap < map->len && test_bit(gap, map->tsn_map))
	103	return 1;
1da177e4	104	else
8e1ee18c	105	return 0;
1da177e4 LT	106	}
	107
	108
	109	/* Mark this TSN as seen. */
4244854d NH	110	int sctp_tsnmap_mark(struct sctp_tsnmap *map, __u32 tsn,
4244854d NH	111	struct sctp_transport *trans)
1da177e4	112	{
8e1ee18c	113	u16 gap;
1da177e4	114
1da177e4	115	if (TSN_lt(tsn, map->base_tsn))
8e1ee18c	116	return 0;
1da177e4	117
1da177e4 LT	118	gap = tsn - map->base_tsn;
1da177e4 LT	119
70fc69bc	120	if (gap >= map->len && !sctp_tsnmap_grow(map, gap + 1))
8e1ee18c	121	return -ENOMEM;
1da177e4	122
8e1ee18c VY	123	if (!sctp_tsnmap_has_gap(map) && gap == 0) {
	124	/* In this case the map has no gaps and the tsn we are
	125	* recording is the next expected tsn. We don't touch
	126	* the map but simply bump the values.
	127	*/
	128	map->max_tsn_seen++;
	129	map->cumulative_tsn_ack_point++;
4244854d NH	130	if (trans)
	131	trans->sack_generation =
	132	trans->asoc->peer.sack_generation;
8e1ee18c VY	133	map->base_tsn++;
	134	} else {
	135	/* Either we already have a gap, or about to record a gap, so
	136	* have work to do.
	137	*
	138	* Bump the max.
	139	*/
	140	if (TSN_lt(map->max_tsn_seen, tsn))
	141	map->max_tsn_seen = tsn;
	142
	143	/* Mark the TSN as received. */
	144	set_bit(gap, map->tsn_map);
	145
	146	/* Go fixup any internal TSN mapping variables including
	147	* cumulative_tsn_ack_point.
	148	*/
	149	sctp_tsnmap_update(map);
	150	}
	151
	152	return 0;
1da177e4 LT	153	}
	154
	155
	156	/* Initialize a Gap Ack Block iterator from memory being provided. */
dda91928 DB	157	static void sctp_tsnmap_iter_init(const struct sctp_tsnmap *map,
dda91928 DB	158	struct sctp_tsnmap_iter *iter)
1da177e4 LT	159	{
	160	/* Only start looking one past the Cumulative TSN Ack Point. */
	161	iter->start = map->cumulative_tsn_ack_point + 1;
	162	}
	163
	164	/* Get the next Gap Ack Blocks. Returns 0 if there was not another block
	165	* to get.
	166	*/
dda91928 DB	167	static int sctp_tsnmap_next_gap_ack(const struct sctp_tsnmap *map,
	168	struct sctp_tsnmap_iter *iter,
	169	__u16 start, __u16 end)
1da177e4	170	{
8e1ee18c VY	171	int ended = 0;
8e1ee18c VY	172	__u16 start_ = 0, end_ = 0, offset;
1da177e4 LT	173
	174	/* If there are no more gap acks possible, get out fast. */
	175	if (TSN_lte(map->max_tsn_seen, iter->start))
	176	return 0;
	177
8e1ee18c VY	178	offset = iter->start - map->base_tsn;
	179	sctp_tsnmap_find_gap_ack(map->tsn_map, offset, map->len,
	180	&start_, &end_);
1da177e4	181
8e1ee18c VY	182	/* The Gap Ack Block happens to end at the end of the map. */
	183	if (start_ && !end_)
	184	end_ = map->len - 1;
1da177e4 LT	185
	186	/* If we found a Gap Ack Block, return the start and end and
	187	* bump the iterator forward.
	188	*/
8e1ee18c	189	if (end_) {
1da177e4	190	/* Fix up the start and end based on the
8e1ee18c	191	* Cumulative TSN Ack which is always 1 behind base.
1da177e4	192	*/
8e1ee18c VY	193	*start = start_ + 1;
8e1ee18c VY	194	*end = end_ + 1;
1da177e4 LT	195
	196	/* Move the iterator forward. */
	197	iter->start = map->cumulative_tsn_ack_point + *end + 1;
8e1ee18c	198	ended = 1;
1da177e4 LT	199	}
	200
	201	return ended;
	202	}
	203
	204	/* Mark this and any lower TSN as seen. */
	205	void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn)
	206	{
8e1ee18c	207	u32 gap;
1da177e4	208
1da177e4 LT	209	if (TSN_lt(tsn, map->base_tsn))
1da177e4 LT	210	return;
8e1ee18c	211	if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
1da177e4 LT	212	return;
	213
	214	/* Bump the max. */
	215	if (TSN_lt(map->max_tsn_seen, tsn))
	216	map->max_tsn_seen = tsn;
	217
1da177e4 LT	218	gap = tsn - map->base_tsn + 1;
1da177e4 LT	219
8e1ee18c VY	220	map->base_tsn += gap;
	221	map->cumulative_tsn_ack_point += gap;
	222	if (gap >= map->len) {
	223	/* If our gap is larger then the map size, just
	224	* zero out the map.
	225	*/
	226	bitmap_zero(map->tsn_map, map->len);
	227	} else {
025dfdaf	228	/* If the gap is smaller than the map size,
8e1ee18c VY	229	* shift the map by 'gap' bits and update further.
	230	*/
	231	bitmap_shift_right(map->tsn_map, map->tsn_map, gap, map->len);
	232	sctp_tsnmap_update(map);
1da177e4	233	}
1da177e4 LT	234	}
	235
	236	/********************************************************************
	237	* 2nd Level Abstractions
	238	********************************************************************/
	239
	240	/* This private helper function updates the tsnmap buffers and
	241	* the Cumulative TSN Ack Point.
	242	*/
	243	static void sctp_tsnmap_update(struct sctp_tsnmap *map)
	244	{
8e1ee18c VY	245	u16 len;
	246	unsigned long zero_bit;
	247
	248
	249	len = map->max_tsn_seen - map->cumulative_tsn_ack_point;
	250	zero_bit = find_first_zero_bit(map->tsn_map, len);
	251	if (!zero_bit)
	252	return; /* The first 0-bit is bit 0. nothing to do */
	253
	254	map->base_tsn += zero_bit;
	255	map->cumulative_tsn_ack_point += zero_bit;
1da177e4	256
8e1ee18c	257	bitmap_shift_right(map->tsn_map, map->tsn_map, zero_bit, map->len);
1da177e4 LT	258	}
	259
	260	/* How many data chunks are we missing from our peer?
	261	*/
	262	__u16 sctp_tsnmap_pending(struct sctp_tsnmap *map)
	263	{
	264	__u32 cum_tsn = map->cumulative_tsn_ack_point;
	265	__u32 max_tsn = map->max_tsn_seen;
	266	__u32 base_tsn = map->base_tsn;
	267	__u16 pending_data;
fc184f08	268	u32 gap;
1da177e4 LT	269
	270	pending_data = max_tsn - cum_tsn;
	271	gap = max_tsn - base_tsn;
	272
8e1ee18c	273	if (gap == 0 \|\| gap >= map->len)
1da177e4 LT	274	goto out;
1da177e4 LT	275
fc184f08	276	pending_data -= bitmap_weight(map->tsn_map, gap + 1);
1da177e4 LT	277	out:
	278	return pending_data;
	279	}
	280
	281	/* This is a private helper for finding Gap Ack Blocks. It searches a
	282	* single array for the start and end of a Gap Ack Block.
	283	*
	284	* The flags "started" and "ended" tell is if we found the beginning
	285	* or (respectively) the end of a Gap Ack Block.
	286	*/
8e1ee18c VY	287	static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
8e1ee18c VY	288	__u16 len, __u16 start, __u16 end)
1da177e4 LT	289	{
	290	int i = off;
	291
	292	/* Look through the entire array, but break out
	293	* early if we have found the end of the Gap Ack Block.
	294	*/
	295
	296	/* Also, stop looking past the maximum TSN seen. */
	297
	298	/* Look for the start. */
8e1ee18c VY	299	i = find_next_bit(map, len, off);
	300	if (i < len)
	301	*start = i;
1da177e4 LT	302
1da177e4 LT	303	/* Look for the end. */
8e1ee18c	304	if (*start) {
1da177e4 LT	305	/* We have found the start, let's find the
	306	* end. If we find the end, break out.
	307	*/
8e1ee18c VY	308	i = find_next_zero_bit(map, len, i);
	309	if (i < len)
	310	*end = i - 1;
1da177e4 LT	311	}
	312	}
	313
	314	/* Renege that we have seen a TSN. */
	315	void sctp_tsnmap_renege(struct sctp_tsnmap *map, __u32 tsn)
	316	{
8e1ee18c	317	u32 gap;
1da177e4 LT	318
	319	if (TSN_lt(tsn, map->base_tsn))
	320	return;
8e1ee18c VY	321	/* Assert: TSN is in range. */
8e1ee18c VY	322	if (!TSN_lt(tsn, map->base_tsn + map->len))
1da177e4 LT	323	return;
1da177e4 LT	324
1da177e4 LT	325	gap = tsn - map->base_tsn;
	326
	327	/* Pretend we never saw the TSN. */
8e1ee18c	328	clear_bit(gap, map->tsn_map);
1da177e4 LT	329	}
	330
	331	/* How many gap ack blocks do we have recorded? */
02015180 VY	332	__u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
02015180 VY	333	struct sctp_gap_ack_block *gabs)
1da177e4 LT	334	{
1da177e4 LT	335	struct sctp_tsnmap_iter iter;
02015180	336	int ngaps = 0;
1da177e4 LT	337
	338	/* Refresh the gap ack information. */
	339	if (sctp_tsnmap_has_gap(map)) {
59ed5aba	340	__u16 start = 0, end = 0;
1da177e4 LT	341	sctp_tsnmap_iter_init(map, &iter);
1da177e4 LT	342	while (sctp_tsnmap_next_gap_ack(map, &iter,
9f81bcd9 AV	343	&start,
9f81bcd9 AV	344	&end)) {
1da177e4	345
02015180 VY	346	gabs[ngaps].start = htons(start);
	347	gabs[ngaps].end = htons(end);
	348	ngaps++;
	349	if (ngaps >= SCTP_MAX_GABS)
1da177e4 LT	350	break;
	351	}
	352	}
02015180	353	return ngaps;
1da177e4	354	}
8e1ee18c	355
70fc69bc	356	static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 size)
8e1ee18c VY	357	{
	358	unsigned long *new;
	359	unsigned long inc;
	360	u16 len;
	361
70fc69bc	362	if (size > SCTP_TSN_MAP_SIZE)
8e1ee18c VY	363	return 0;
8e1ee18c VY	364
70fc69bc	365	inc = ALIGN((size - map->len), BITS_PER_LONG) + SCTP_TSN_MAP_INCREMENT;
8e1ee18c VY	366	len = min_t(u16, map->len + inc, SCTP_TSN_MAP_SIZE);
	367
	368	new = kzalloc(len>>3, GFP_ATOMIC);
	369	if (!new)
	370	return 0;
	371
70fc69bc LR	372	bitmap_copy(new, map->tsn_map,
70fc69bc LR	373	map->max_tsn_seen - map->cumulative_tsn_ack_point);
8e1ee18c VY	374	kfree(map->tsn_map);
	375	map->tsn_map = new;
	376	map->len = len;
	377
	378	return 1;
	379	}