208 lines
6.4 KiB
C
208 lines
6.4 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 are the definitions needed for the tsnmap type. The tsnmap is used
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* to track out of order TSNs received.
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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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* Jon Grimm <jgrimm@us.ibm.com>
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* La Monte H.P. Yarroll <piggy@acm.org>
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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 <net/sctp/constants.h>
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#ifndef __sctp_tsnmap_h__
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#define __sctp_tsnmap_h__
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/* RFC 2960 12.2 Parameters necessary per association (i.e. the TCB)
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* Mapping An array of bits or bytes indicating which out of
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* Array order TSN's have been received (relative to the
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* Last Rcvd TSN). If no gaps exist, i.e. no out of
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* order packets have been received, this array
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* will be set to all zero. This structure may be
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* in the form of a circular buffer or bit array.
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*/
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struct sctp_tsnmap {
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/* This array counts the number of chunks with each TSN.
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* It points at one of the two buffers with which we will
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* ping-pong between.
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*/
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__u8 *tsn_map;
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/* This marks the tsn which overflows the tsn_map, when the
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* cumulative ack point reaches this point we know we can switch
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* maps (tsn_map and overflow_map swap).
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*/
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__u32 overflow_tsn;
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/* This is the overflow array for tsn_map.
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* It points at one of the other ping-pong buffers.
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*/
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__u8 *overflow_map;
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/* This is the TSN at tsn_map[0]. */
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__u32 base_tsn;
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/* Last Rcvd : This is the last TSN received in
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* TSN : sequence. This value is set initially by
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* : taking the peer's Initial TSN, received in
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* : the INIT or INIT ACK chunk, and subtracting
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* : one from it.
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*
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* Throughout most of the specification this is called the
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* "Cumulative TSN ACK Point". In this case, we
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* ignore the advice in 12.2 in favour of the term
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* used in the bulk of the text.
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*/
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__u32 cumulative_tsn_ack_point;
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/* This is the minimum number of TSNs we can track. This corresponds
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* to the size of tsn_map. Note: the overflow_map allows us to
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* potentially track more than this quantity.
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*/
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__u16 len;
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/* This is the highest TSN we've marked. */
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__u32 max_tsn_seen;
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/* Data chunks pending receipt. used by SCTP_STATUS sockopt */
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__u16 pending_data;
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/* Record duplicate TSNs here. We clear this after
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* every SACK. Store up to SCTP_MAX_DUP_TSNS worth of
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* information.
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*/
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__be32 dup_tsns[SCTP_MAX_DUP_TSNS];
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__u16 num_dup_tsns;
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/* Record gap ack block information here. */
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struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
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int malloced;
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__u8 raw_map[0];
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};
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struct sctp_tsnmap_iter {
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__u32 start;
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};
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/* This macro assists in creation of external storage for variable length
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* internal buffers. We double allocate so the overflow map works.
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*/
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#define sctp_tsnmap_storage_size(count) (sizeof(__u8) * (count) * 2)
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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 *, __u16 len,
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__u32 initial_tsn);
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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 *, __u32 tsn);
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/* Mark this TSN as seen. */
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void sctp_tsnmap_mark(struct sctp_tsnmap *, __u32 tsn);
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/* Mark this TSN and all lower as seen. */
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void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn);
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/* Retrieve the Cumulative TSN ACK Point. */
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static inline __u32 sctp_tsnmap_get_ctsn(const struct sctp_tsnmap *map)
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{
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return map->cumulative_tsn_ack_point;
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}
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/* Retrieve the highest TSN we've seen. */
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static inline __u32 sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap *map)
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{
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return map->max_tsn_seen;
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}
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/* How many duplicate TSNs are stored? */
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static inline __u16 sctp_tsnmap_num_dups(struct sctp_tsnmap *map)
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{
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return map->num_dup_tsns;
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}
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/* Return pointer to duplicate tsn array as needed by SACK. */
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static inline __be32 *sctp_tsnmap_get_dups(struct sctp_tsnmap *map)
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{
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map->num_dup_tsns = 0;
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return map->dup_tsns;
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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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/* Refresh the count on pending data. */
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__u16 sctp_tsnmap_pending(struct sctp_tsnmap *map);
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/* Return pointer to gap ack blocks as needed by SACK. */
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static inline struct sctp_gap_ack_block *sctp_tsnmap_get_gabs(struct sctp_tsnmap *map)
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{
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return map->gabs;
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}
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/* Is there a gap in the TSN map? */
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static inline int sctp_tsnmap_has_gap(const struct sctp_tsnmap *map)
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{
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int has_gap;
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has_gap = (map->cumulative_tsn_ack_point != map->max_tsn_seen);
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return has_gap;
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}
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/* Mark a duplicate TSN. Note: limit the storage of duplicate TSN
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* information.
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*/
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static inline void sctp_tsnmap_mark_dup(struct sctp_tsnmap *map, __u32 tsn)
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{
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if (map->num_dup_tsns < SCTP_MAX_DUP_TSNS)
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map->dup_tsns[map->num_dup_tsns++] = htonl(tsn);
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}
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/* Renege a TSN that was seen. */
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void sctp_tsnmap_renege(struct sctp_tsnmap *, __u32 tsn);
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/* Is there a gap in the TSN map? */
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int sctp_tsnmap_has_gap(const struct sctp_tsnmap *);
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#endif /* __sctp_tsnmap_h__ */
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