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59ed5aba9c
net/sctp/tsnmap.c: In function ‘sctp_tsnmap_num_gabs’: net/sctp/tsnmap.c:347: warning: ‘start’ may be used uninitialized in this function net/sctp/tsnmap.c:347: warning: ‘end’ may be used uninitialized in this function Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
386 lines
9.7 KiB
C
386 lines
9.7 KiB
C
/* SCTP kernel implementation
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* (C) Copyright IBM Corp. 2001, 2004
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* Copyright (c) 1999-2000 Cisco, Inc.
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* Copyright (c) 1999-2001 Motorola, Inc.
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* Copyright (c) 2001 Intel Corp.
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*
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* This file is part of the SCTP kernel implementation
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*
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* These functions manipulate sctp tsn mapping array.
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*
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* This SCTP implementation is free software;
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* you can redistribute it and/or modify it under the terms of
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* the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This SCTP implementation is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied
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* ************************
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU CC; see the file COPYING. If not, write to
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* the Free Software Foundation, 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*
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* Please send any bug reports or fixes you make to the
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* email address(es):
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* lksctp developers <lksctp-developers@lists.sourceforge.net>
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*
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* Or submit a bug report through the following website:
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* http://www.sf.net/projects/lksctp
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*
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* Written or modified by:
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* La Monte H.P. Yarroll <piggy@acm.org>
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* Jon Grimm <jgrimm@us.ibm.com>
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* Karl Knutson <karl@athena.chicago.il.us>
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* Sridhar Samudrala <sri@us.ibm.com>
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*
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* Any bugs reported given to us we will try to fix... any fixes shared will
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* be incorporated into the next SCTP release.
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*/
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/bitmap.h>
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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static void sctp_tsnmap_update(struct sctp_tsnmap *map);
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static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
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__u16 len, __u16 *start, __u16 *end);
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static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 gap);
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/* Initialize a block of memory as a tsnmap. */
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struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *map, __u16 len,
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__u32 initial_tsn, gfp_t gfp)
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{
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if (!map->tsn_map) {
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map->tsn_map = kzalloc(len>>3, gfp);
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if (map->tsn_map == NULL)
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return NULL;
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map->len = len;
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} else {
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bitmap_zero(map->tsn_map, map->len);
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}
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/* Keep track of TSNs represented by tsn_map. */
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map->base_tsn = initial_tsn;
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map->cumulative_tsn_ack_point = initial_tsn - 1;
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map->max_tsn_seen = map->cumulative_tsn_ack_point;
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map->num_dup_tsns = 0;
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return map;
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}
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void sctp_tsnmap_free(struct sctp_tsnmap *map)
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{
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map->len = 0;
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kfree(map->tsn_map);
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}
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/* Test the tracking state of this TSN.
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* Returns:
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* 0 if the TSN has not yet been seen
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* >0 if the TSN has been seen (duplicate)
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* <0 if the TSN is invalid (too large to track)
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*/
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int sctp_tsnmap_check(const struct sctp_tsnmap *map, __u32 tsn)
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{
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u32 gap;
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/* Check to see if this is an old TSN */
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if (TSN_lte(tsn, map->cumulative_tsn_ack_point))
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return 1;
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/* Verify that we can hold this TSN and that it will not
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* overlfow our map
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*/
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if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
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return -1;
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/* Calculate the index into the mapping arrays. */
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gap = tsn - map->base_tsn;
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/* Check to see if TSN has already been recorded. */
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if (gap < map->len && test_bit(gap, map->tsn_map))
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return 1;
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else
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return 0;
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}
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/* Mark this TSN as seen. */
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int sctp_tsnmap_mark(struct sctp_tsnmap *map, __u32 tsn)
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{
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u16 gap;
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if (TSN_lt(tsn, map->base_tsn))
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return 0;
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gap = tsn - map->base_tsn;
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if (gap >= map->len && !sctp_tsnmap_grow(map, gap))
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return -ENOMEM;
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if (!sctp_tsnmap_has_gap(map) && gap == 0) {
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/* In this case the map has no gaps and the tsn we are
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* recording is the next expected tsn. We don't touch
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* the map but simply bump the values.
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*/
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map->max_tsn_seen++;
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map->cumulative_tsn_ack_point++;
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map->base_tsn++;
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} else {
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/* Either we already have a gap, or about to record a gap, so
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* have work to do.
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*
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* Bump the max.
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*/
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if (TSN_lt(map->max_tsn_seen, tsn))
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map->max_tsn_seen = tsn;
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/* Mark the TSN as received. */
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set_bit(gap, map->tsn_map);
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/* Go fixup any internal TSN mapping variables including
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* cumulative_tsn_ack_point.
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*/
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sctp_tsnmap_update(map);
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}
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return 0;
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}
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/* Initialize a Gap Ack Block iterator from memory being provided. */
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SCTP_STATIC void sctp_tsnmap_iter_init(const struct sctp_tsnmap *map,
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struct sctp_tsnmap_iter *iter)
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{
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/* Only start looking one past the Cumulative TSN Ack Point. */
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iter->start = map->cumulative_tsn_ack_point + 1;
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}
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/* Get the next Gap Ack Blocks. Returns 0 if there was not another block
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* to get.
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*/
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SCTP_STATIC int sctp_tsnmap_next_gap_ack(const struct sctp_tsnmap *map,
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struct sctp_tsnmap_iter *iter,
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__u16 *start, __u16 *end)
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{
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int ended = 0;
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__u16 start_ = 0, end_ = 0, offset;
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/* If there are no more gap acks possible, get out fast. */
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if (TSN_lte(map->max_tsn_seen, iter->start))
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return 0;
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offset = iter->start - map->base_tsn;
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sctp_tsnmap_find_gap_ack(map->tsn_map, offset, map->len,
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&start_, &end_);
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/* The Gap Ack Block happens to end at the end of the map. */
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if (start_ && !end_)
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end_ = map->len - 1;
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/* If we found a Gap Ack Block, return the start and end and
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* bump the iterator forward.
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*/
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if (end_) {
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/* Fix up the start and end based on the
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* Cumulative TSN Ack which is always 1 behind base.
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*/
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*start = start_ + 1;
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*end = end_ + 1;
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/* Move the iterator forward. */
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iter->start = map->cumulative_tsn_ack_point + *end + 1;
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ended = 1;
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}
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return ended;
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}
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/* Mark this and any lower TSN as seen. */
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void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn)
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{
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u32 gap;
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if (TSN_lt(tsn, map->base_tsn))
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return;
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if (!TSN_lt(tsn, map->base_tsn + SCTP_TSN_MAP_SIZE))
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return;
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/* Bump the max. */
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if (TSN_lt(map->max_tsn_seen, tsn))
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map->max_tsn_seen = tsn;
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gap = tsn - map->base_tsn + 1;
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map->base_tsn += gap;
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map->cumulative_tsn_ack_point += gap;
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if (gap >= map->len) {
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/* If our gap is larger then the map size, just
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* zero out the map.
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*/
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bitmap_zero(map->tsn_map, map->len);
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} else {
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/* If the gap is smaller than the map size,
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* shift the map by 'gap' bits and update further.
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*/
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bitmap_shift_right(map->tsn_map, map->tsn_map, gap, map->len);
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sctp_tsnmap_update(map);
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}
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}
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/********************************************************************
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* 2nd Level Abstractions
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********************************************************************/
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/* This private helper function updates the tsnmap buffers and
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* the Cumulative TSN Ack Point.
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*/
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static void sctp_tsnmap_update(struct sctp_tsnmap *map)
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{
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u16 len;
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unsigned long zero_bit;
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len = map->max_tsn_seen - map->cumulative_tsn_ack_point;
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zero_bit = find_first_zero_bit(map->tsn_map, len);
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if (!zero_bit)
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return; /* The first 0-bit is bit 0. nothing to do */
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map->base_tsn += zero_bit;
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map->cumulative_tsn_ack_point += zero_bit;
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bitmap_shift_right(map->tsn_map, map->tsn_map, zero_bit, map->len);
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}
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/* How many data chunks are we missing from our peer?
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*/
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__u16 sctp_tsnmap_pending(struct sctp_tsnmap *map)
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{
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__u32 cum_tsn = map->cumulative_tsn_ack_point;
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__u32 max_tsn = map->max_tsn_seen;
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__u32 base_tsn = map->base_tsn;
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__u16 pending_data;
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u32 gap, i;
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pending_data = max_tsn - cum_tsn;
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gap = max_tsn - base_tsn;
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if (gap == 0 || gap >= map->len)
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goto out;
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for (i = 0; i < gap+1; i++) {
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if (test_bit(i, map->tsn_map))
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pending_data--;
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}
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out:
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return pending_data;
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}
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/* This is a private helper for finding Gap Ack Blocks. It searches a
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* single array for the start and end of a Gap Ack Block.
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*
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* The flags "started" and "ended" tell is if we found the beginning
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* or (respectively) the end of a Gap Ack Block.
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*/
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static void sctp_tsnmap_find_gap_ack(unsigned long *map, __u16 off,
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__u16 len, __u16 *start, __u16 *end)
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{
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int i = off;
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/* Look through the entire array, but break out
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* early if we have found the end of the Gap Ack Block.
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*/
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/* Also, stop looking past the maximum TSN seen. */
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/* Look for the start. */
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i = find_next_bit(map, len, off);
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if (i < len)
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*start = i;
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/* Look for the end. */
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if (*start) {
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/* We have found the start, let's find the
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* end. If we find the end, break out.
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*/
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i = find_next_zero_bit(map, len, i);
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if (i < len)
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*end = i - 1;
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}
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}
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/* Renege that we have seen a TSN. */
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void sctp_tsnmap_renege(struct sctp_tsnmap *map, __u32 tsn)
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{
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u32 gap;
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if (TSN_lt(tsn, map->base_tsn))
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return;
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/* Assert: TSN is in range. */
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if (!TSN_lt(tsn, map->base_tsn + map->len))
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return;
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gap = tsn - map->base_tsn;
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/* Pretend we never saw the TSN. */
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clear_bit(gap, map->tsn_map);
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}
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/* How many gap ack blocks do we have recorded? */
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__u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
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struct sctp_gap_ack_block *gabs)
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{
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struct sctp_tsnmap_iter iter;
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int ngaps = 0;
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/* Refresh the gap ack information. */
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if (sctp_tsnmap_has_gap(map)) {
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__u16 start = 0, end = 0;
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sctp_tsnmap_iter_init(map, &iter);
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while (sctp_tsnmap_next_gap_ack(map, &iter,
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&start,
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&end)) {
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gabs[ngaps].start = htons(start);
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gabs[ngaps].end = htons(end);
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ngaps++;
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if (ngaps >= SCTP_MAX_GABS)
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break;
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}
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}
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return ngaps;
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}
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static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 gap)
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{
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unsigned long *new;
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unsigned long inc;
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u16 len;
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if (gap >= SCTP_TSN_MAP_SIZE)
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return 0;
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inc = ALIGN((gap - map->len),BITS_PER_LONG) + SCTP_TSN_MAP_INCREMENT;
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len = min_t(u16, map->len + inc, SCTP_TSN_MAP_SIZE);
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new = kzalloc(len>>3, GFP_ATOMIC);
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if (!new)
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return 0;
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bitmap_copy(new, map->tsn_map, map->max_tsn_seen - map->base_tsn);
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kfree(map->tsn_map);
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map->tsn_map = new;
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map->len = len;
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return 1;
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}
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