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 <lksctp-developers@lists.sourceforge.net>
  32  *
  33  * Or submit a bug report through the following website:
  34  *    http://www.sf.net/projects/lksctp
  35  *
  36  * Written or modified by:
  37  *   Jon Grimm             <jgrimm@us.ibm.com>
  38  *   La Monte H.P. Yarroll <piggy@acm.org>
  39  *   Karl Knutson          <karl@athena.chicago.il.us>
  40  *   Sridhar Samudrala     <sri@us.ibm.com>
  41  *
  42  * Any bugs reported given to us we will try to fix... any fixes shared will
  43  * be incorporated into the next SCTP release.
  44  */
  45 #include <net/sctp/constants.h>
  46
  47 #ifndef __sctp_tsnmap_h__
  48 #define __sctp_tsnmap_h__
  49
  50 /* RFC 2960 12.2 Parameters necessary per association (i.e. the TCB)
  51  * Mapping  An array of bits or bytes indicating which out of
  52  * Array    order TSN's have been received (relative to the
  53  *          Last Rcvd TSN). If no gaps exist, i.e. no out of
  54  *          order packets have been received, this array
  55  *          will be set to all zero. This structure may be
  56  *          in the form of a circular buffer or bit array.
  57  */
  58 struct sctp_tsnmap {
  59         /* This array counts the number of chunks with each TSN.
  60          * It points at one of the two buffers with which we will
  61          * ping-pong between.
  62          */
  63         unsigned long *tsn_map;
  64
  65         /* This is the TSN at tsn_map[0].  */
  66         __u32 base_tsn;
  67
  68         /* Last Rcvd   : This is the last TSN received in
  69          * TSN         : sequence. This value is set initially by
  70          *             : taking the peer's Initial TSN, received in
  71          *             : the INIT or INIT ACK chunk, and subtracting
  72          *             : one from it.
  73          *
  74          * Throughout most of the specification this is called the
  75          * "Cumulative TSN ACK Point".  In this case, we
  76          * ignore the advice in 12.2 in favour of the term
  77          * used in the bulk of the text.
  78          */
  79         __u32 cumulative_tsn_ack_point;
  80
  81         /* This is the highest TSN we've marked.  */
  82         __u32 max_tsn_seen;
  83
  84         /* This is the minimum number of TSNs we can track.  This corresponds
  85          * to the size of tsn_map.   Note: the overflow_map allows us to
  86          * potentially track more than this quantity.
  87          */
  88         __u16 len;
  89
  90         /* Data chunks pending receipt. used by SCTP_STATUS sockopt */
  91         __u16 pending_data;
  92
  93         /* Record duplicate TSNs here.  We clear this after
  94          * every SACK.  Store up to SCTP_MAX_DUP_TSNS worth of
  95          * information.
  96          */
  97         __u16 num_dup_tsns;
  98         __be32 dup_tsns[SCTP_MAX_DUP_TSNS];
  99 };
 100
 101 struct sctp_tsnmap_iter {
 102         __u32 start;
 103 };
 104
 105 /* Initialize a block of memory as a tsnmap.  */
 106 struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *, __u16 len,
 107                                      __u32 initial_tsn, gfp_t gfp);
 108
 109 void sctp_tsnmap_free(struct sctp_tsnmap *map);
 110
 111 /* Test the tracking state of this TSN.
 112  * Returns:
 113  *   0 if the TSN has not yet been seen
 114  *  >0 if the TSN has been seen (duplicate)
 115  *  <0 if the TSN is invalid (too large to track)
 116  */
 117 int sctp_tsnmap_check(const struct sctp_tsnmap *, __u32 tsn);
 118
 119 /* Mark this TSN as seen.  */
 120 int sctp_tsnmap_mark(struct sctp_tsnmap *, __u32 tsn);
 121
 122 /* Mark this TSN and all lower as seen. */
 123 void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn);
 124
 125 /* Retrieve the Cumulative TSN ACK Point.  */
 126 static inline __u32 sctp_tsnmap_get_ctsn(const struct sctp_tsnmap *map)
 127 {
 128         return map->cumulative_tsn_ack_point;
 129 }
 130
 131 /* Retrieve the highest TSN we've seen.  */
 132 static inline __u32 sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap *map)
 133 {
 134         return map->max_tsn_seen;
 135 }
 136
 137 /* How many duplicate TSNs are stored? */
 138 static inline __u16 sctp_tsnmap_num_dups(struct sctp_tsnmap *map)
 139 {
 140         return map->num_dup_tsns;
 141 }
 142
 143 /* Return pointer to duplicate tsn array as needed by SACK. */
 144 static inline __be32 *sctp_tsnmap_get_dups(struct sctp_tsnmap *map)
 145 {
 146         map->num_dup_tsns = 0;
 147         return map->dup_tsns;
 148 }
 149
 150 /* How many gap ack blocks do we have recorded? */
 151 __u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
 152                            struct sctp_gap_ack_block *gabs);
 153
 154 /* Refresh the count on pending data. */
 155 __u16 sctp_tsnmap_pending(struct sctp_tsnmap *map);
 156
 157 /* Is there a gap in the TSN map?  */
 158 static inline int sctp_tsnmap_has_gap(const struct sctp_tsnmap *map)
 159 {
 160         return map->cumulative_tsn_ack_point != map->max_tsn_seen;
 161 }
 162
 163 /* Mark a duplicate TSN.  Note:  limit the storage of duplicate TSN
 164  * information.
 165  */
 166 static inline void sctp_tsnmap_mark_dup(struct sctp_tsnmap *map, __u32 tsn)
 167 {
 168         if (map->num_dup_tsns < SCTP_MAX_DUP_TSNS)
 169                 map->dup_tsns[map->num_dup_tsns++] = htonl(tsn);
 170 }
 171
 172 /* Renege a TSN that was seen.  */
 173 void sctp_tsnmap_renege(struct sctp_tsnmap *, __u32 tsn);
 174
 175 /* Is there a gap in the TSN map? */
 176 int sctp_tsnmap_has_gap(const struct sctp_tsnmap *);
 177
 178 #endif /* __sctp_tsnmap_h__ */