include/net/sctp/tsnmap.h

   1 /* SCTP kernel implementation
   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  *
   7  * This file is part of the SCTP kernel implementation
   8  *
   9  * These are the definitions needed for the tsnmap type.  The tsnmap is used
  10  * to track out of order TSNs received.
  11  *
  12  * This SCTP implementation is free software;
  13  * you can redistribute it and/or modify it under the terms of
  14  * the GNU General Public License as published by
  15  * the Free Software Foundation; either version 2, or (at your option)
  16  * any later version.
  17  *
  18  * This SCTP implementation is distributed in the hope that it
  19  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  20  *                 ************************
  21  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  22  * See the GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with GNU CC; see the file COPYING.  If not, write to
  26  * the Free Software Foundation, 59 Temple Place - Suite 330,
  27  * Boston, MA 02111-1307, USA.
  28  *
  29  * Please send any bug reports or fixes you make to the
  30  * email address(es):
  31  *    lksctp developers <linux-sctp@vger.kernel.org>
  32  *
  33  * Written or modified by:
  34  *   Jon Grimm             <jgrimm@us.ibm.com>
  35  *   La Monte H.P. Yarroll <piggy@acm.org>
  36  *   Karl Knutson          <karl@athena.chicago.il.us>
  37  *   Sridhar Samudrala     <sri@us.ibm.com>
  38  */
  39 #include <net/sctp/constants.h>
  40
  41 #ifndef __sctp_tsnmap_h__
  42 #define __sctp_tsnmap_h__
  43
  44 /* RFC 2960 12.2 Parameters necessary per association (i.e. the TCB)
  45  * Mapping  An array of bits or bytes indicating which out of
  46  * Array    order TSN's have been received (relative to the
  47  *          Last Rcvd TSN). If no gaps exist, i.e. no out of
  48  *          order packets have been received, this array
  49  *          will be set to all zero. This structure may be
  50  *          in the form of a circular buffer or bit array.
  51  */
  52 struct sctp_tsnmap {
  53         /* This array counts the number of chunks with each TSN.
  54          * It points at one of the two buffers with which we will
  55          * ping-pong between.
  56          */
  57         unsigned long *tsn_map;
  58
  59         /* This is the TSN at tsn_map[0].  */
  60         __u32 base_tsn;
  61
  62         /* Last Rcvd   : This is the last TSN received in
  63          * TSN         : sequence. This value is set initially by
  64          *             : taking the peer's Initial TSN, received in
  65          *             : the INIT or INIT ACK chunk, and subtracting
  66          *             : one from it.
  67          *
  68          * Throughout most of the specification this is called the
  69          * "Cumulative TSN ACK Point".  In this case, we
  70          * ignore the advice in 12.2 in favour of the term
  71          * used in the bulk of the text.
  72          */
  73         __u32 cumulative_tsn_ack_point;
  74
  75         /* This is the highest TSN we've marked.  */
  76         __u32 max_tsn_seen;
  77
  78         /* This is the minimum number of TSNs we can track.  This corresponds
  79          * to the size of tsn_map.   Note: the overflow_map allows us to
  80          * potentially track more than this quantity.
  81          */
  82         __u16 len;
  83
  84         /* Data chunks pending receipt. used by SCTP_STATUS sockopt */
  85         __u16 pending_data;
  86
  87         /* Record duplicate TSNs here.  We clear this after
  88          * every SACK.  Store up to SCTP_MAX_DUP_TSNS worth of
  89          * information.
  90          */
  91         __u16 num_dup_tsns;
  92         __be32 dup_tsns[SCTP_MAX_DUP_TSNS];
  93 };
  94
  95 struct sctp_tsnmap_iter {
  96         __u32 start;
  97 };
  98
  99 /* Initialize a block of memory as a tsnmap.  */
 100 struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *, __u16 len,
 101                                      __u32 initial_tsn, gfp_t gfp);
 102
 103 void sctp_tsnmap_free(struct sctp_tsnmap *map);
 104
 105 /* Test the tracking state of this TSN.
 106  * Returns:
 107  *   0 if the TSN has not yet been seen
 108  *  >0 if the TSN has been seen (duplicate)
 109  *  <0 if the TSN is invalid (too large to track)
 110  */
 111 int sctp_tsnmap_check(const struct sctp_tsnmap *, __u32 tsn);
 112
 113 /* Mark this TSN as seen.  */
 114 int sctp_tsnmap_mark(struct sctp_tsnmap *, __u32 tsn,
 115                      struct sctp_transport *trans);
 116
 117 /* Mark this TSN and all lower as seen. */
 118 void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn);
 119
 120 /* Retrieve the Cumulative TSN ACK Point.  */
 121 static inline __u32 sctp_tsnmap_get_ctsn(const struct sctp_tsnmap *map)
 122 {
 123         return map->cumulative_tsn_ack_point;
 124 }
 125
 126 /* Retrieve the highest TSN we've seen.  */
 127 static inline __u32 sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap *map)
 128 {
 129         return map->max_tsn_seen;
 130 }
 131
 132 /* How many duplicate TSNs are stored? */
 133 static inline __u16 sctp_tsnmap_num_dups(struct sctp_tsnmap *map)
 134 {
 135         return map->num_dup_tsns;
 136 }
 137
 138 /* Return pointer to duplicate tsn array as needed by SACK. */
 139 static inline __be32 *sctp_tsnmap_get_dups(struct sctp_tsnmap *map)
 140 {
 141         map->num_dup_tsns = 0;
 142         return map->dup_tsns;
 143 }
 144
 145 /* How many gap ack blocks do we have recorded? */
 146 __u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
 147                            struct sctp_gap_ack_block *gabs);
 148
 149 /* Refresh the count on pending data. */
 150 __u16 sctp_tsnmap_pending(struct sctp_tsnmap *map);
 151
 152 /* Is there a gap in the TSN map?  */
 153 static inline int sctp_tsnmap_has_gap(const struct sctp_tsnmap *map)
 154 {
 155         return map->cumulative_tsn_ack_point != map->max_tsn_seen;
 156 }
 157
 158 /* Mark a duplicate TSN.  Note:  limit the storage of duplicate TSN
 159  * information.
 160  */
 161 static inline void sctp_tsnmap_mark_dup(struct sctp_tsnmap *map, __u32 tsn)
 162 {
 163         if (map->num_dup_tsns < SCTP_MAX_DUP_TSNS)
 164                 map->dup_tsns[map->num_dup_tsns++] = htonl(tsn);
 165 }
 166
 167 /* Renege a TSN that was seen.  */
 168 void sctp_tsnmap_renege(struct sctp_tsnmap *, __u32 tsn);
 169
 170 /* Is there a gap in the TSN map? */
 171 int sctp_tsnmap_has_gap(const struct sctp_tsnmap *);
 172
 173 #endif /* __sctp_tsnmap_h__ */