linux/net/sctp/tsnmap.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* 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.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <[email protected]>
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <[email protected]>
 *    Jon Grimm             <[email protected]>
 *    Karl Knutson          <[email protected]>
 *    Sridhar Samudrala     <[email protected]>
 */

#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)
{ … }

void sctp_tsnmap_free(struct sctp_tsnmap *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)
{ … }


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


/* 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)
{ … }

/* 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)
{ … }

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

/********************************************************************
 * 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)
{ … }

/* How many data chunks  are we missing from our peer?
 */
__u16 sctp_tsnmap_pending(struct sctp_tsnmap *map)
{ … }

/* 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)
{ … }

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

/* How many gap ack blocks do we have recorded? */
__u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
			   struct sctp_gap_ack_block *gabs)
{ … }

static int sctp_tsnmap_grow(struct sctp_tsnmap *map, u16 size)
{ … }