Release 4.11 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;
}

Contributors
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Jon Grimm
68
64.15%
2
50.00%
Vladislav Yasevich
36
33.96%
1
25.00%
David S. Miller
2
1.89%
1
25.00%
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106
100.00%
4
100.00%



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

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Vladislav Yasevich
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69.57%
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Jon Grimm
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30.43%
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/* 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;
}


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Jon Grimm
42
49.41%
2
50.00%
Vladislav Yasevich
41
48.24%
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25.00%
David S. Miller
2
2.35%
1
25.00%
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85
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4
100.00%

/* 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;
}


Contributors
Person
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CommitProp
Jon Grimm
65
43.05%
2
33.33%
Vladislav Yasevich
62
41.06%
1
16.67%
Neil Horman
21
13.91%
1
16.67%
Lee A. Roberts
2
1.32%
1
16.67%
David S. Miller
1
0.66%
1
16.67%
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151
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6
100.00%

/* 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;
}

Contributors
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CommitProp
Jon Grimm
26
92.86%
2
50.00%
Daniel Borkmann
1
3.57%
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David S. Miller
1
3.57%
1
25.00%
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28
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/* 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;
}

Contributors
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Jon Grimm
112
76.71%
4
50.00%
Vladislav Yasevich
22
15.07%
1
12.50%
Sebastian Andrzej Siewior
7
4.79%
1
12.50%
David S. Miller
4
2.74%
1
12.50%
Daniel Borkmann
1
0.68%
1
12.50%
Total
146
100.00%
8
100.00%

/* 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);
	}
}

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Sridhar Samudrala
104
79.39%
1
33.33%
Vladislav Yasevich
26
19.85%
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33.33%
Frederik Schwarzer
1
0.76%
1
33.33%
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/********************************************************************
 * 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);
}

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Jon Grimm
41
54.67%
2
66.67%
Vladislav Yasevich
34
45.33%
1
33.33%
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75
100.00%
3
100.00%

/* 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;
}

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Jon Grimm
58
70.73%
3
50.00%
Vladislav Yasevich
13
15.85%
1
16.67%
Akinobu Mita
7
8.54%
1
16.67%
David S. Miller
4
4.88%
1
16.67%
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100.00%

/* 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;
	}
}

Contributors
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Jon Grimm
60
68.18%
3
60.00%
Vladislav Yasevich
24
27.27%
1
20.00%
David S. Miller
4
4.55%
1
20.00%
Total
88
100.00%
5
100.00%

/* 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);
}

Contributors
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Jon Grimm
58
90.62%
1
50.00%
Vladislav Yasevich
6
9.38%
1
50.00%
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64
100.00%
2
100.00%

/* 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;
}

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Jon Grimm
86
81.13%
1
25.00%
Vladislav Yasevich
11
10.38%
1
25.00%
Al Viro
5
4.72%
1
25.00%
Shan Wei
4
3.77%
1
25.00%
Total
106
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4
100.00%



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;
}
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Vladislav Yasevich
120
96.00%
1
50.00%
Lee A. Roberts
5
4.00%
1
50.00%
Total
125
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2
100.00%

Overall Contributors
Person
Tokens
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CommitProp
Jon Grimm
670
52.14%
6
28.57%
Vladislav Yasevich
427
33.23%
2
9.52%
Sridhar Samudrala
105
8.17%
1
4.76%
David S. Miller
24
1.87%
2
9.52%
Neil Horman
21
1.63%
1
4.76%
Lee A. Roberts
8
0.62%
1
4.76%
Sebastian Andrzej Siewior
7
0.54%
1
4.76%
Akinobu Mita
7
0.54%
1
4.76%
Al Viro
5
0.39%
1
4.76%
Shan Wei
4
0.31%
1
4.76%
Tejun Heo
3
0.23%
1
4.76%
Daniel Borkmann
2
0.16%
1
4.76%
Jeff Kirsher
1
0.08%
1
4.76%
Frederik Schwarzer
1
0.08%
1
4.76%
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21
100.00%
Directory: net/sctp

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