include/net/sctp/tsnmap.h

   1 /* SCTP kernel reference 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 reference 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  * The SCTP reference 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  * The SCTP reference 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         __u8 *tsn_map;
  64
  65         /* This marks the tsn which overflows the tsn_map, when the
  66          * cumulative ack point reaches this point we know we can switch
  67          * maps (tsn_map and overflow_map swap).
  68          */
  69         __u32 overflow_tsn;
  70
  71         /* This is the overflow array for tsn_map.
  72          * It points at one of the other ping-pong buffers.
  73          */
  74         __u8 *overflow_map;
  75
  76         /* This is the TSN at tsn_map[0].  */
  77         __u32 base_tsn;
  78
  79         /* Last Rcvd   : This is the last TSN received in
  80          * TSN         : sequence. This value is set initially by
  81          *             : taking the peer's Initial TSN, received in
  82          *             : the INIT or INIT ACK chunk, and subtracting
  83          *             : one from it.
  84          *
  85          * Throughout most of the specification this is called the
  86          * "Cumulative TSN ACK Point".  In this case, we
  87          * ignore the advice in 12.2 in favour of the term
  88          * used in the bulk of the text.
  89          */
  90         __u32 cumulative_tsn_ack_point;
  91
  92         /* This is the minimum number of TSNs we can track.  This corresponds
  93          * to the size of tsn_map.   Note: the overflow_map allows us to
  94          * potentially track more than this quantity.
  95          */
  96         __u16 len;
  97
  98         /* This is the highest TSN we've marked.  */
  99         __u32 max_tsn_seen;
 100
 101         /* Data chunks pending receipt. used by SCTP_STATUS sockopt */
 102         __u16 pending_data;
 103
 104         /* Record duplicate TSNs here.  We clear this after
 105          * every SACK.  Store up to SCTP_MAX_DUP_TSNS worth of
 106          * information.
 107          */
 108         __u32 dup_tsns[SCTP_MAX_DUP_TSNS];
 109         __u16 num_dup_tsns;
 110
 111         /* Record gap ack block information here.  */
 112         struct sctp_gap_ack_block gabs[SCTP_MAX_GABS];
 113
 114         int malloced;
 115
 116         __u8 raw_map[0];
 117 };
 118
 119 struct sctp_tsnmap_iter {
 120         __u32 start;
 121 };
 122
 123 /* This macro assists in creation of external storage for variable length
 124  * internal buffers.  We double allocate so the overflow map works.
 125  */
 126 #define sctp_tsnmap_storage_size(count) (sizeof(__u8) * (count) * 2)
 127
 128 /* Initialize a block of memory as a tsnmap.  */
 129 struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *, __u16 len,
 130                                      __u32 initial_tsn);
 131
 132 /* Test the tracking state of this TSN.
 133  * Returns:
 134  *   0 if the TSN has not yet been seen
 135  *  >0 if the TSN has been seen (duplicate)
 136  *  <0 if the TSN is invalid (too large to track)
 137  */
 138 int sctp_tsnmap_check(const struct sctp_tsnmap *, __u32 tsn);
 139
 140 /* Mark this TSN as seen.  */
 141 void sctp_tsnmap_mark(struct sctp_tsnmap *, __u32 tsn);
 142
 143 /* Mark this TSN and all lower as seen. */
 144 void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn);
 145
 146 /* Retrieve the Cumulative TSN ACK Point.  */
 147 static inline __u32 sctp_tsnmap_get_ctsn(const struct sctp_tsnmap *map)
 148 {
 149         return map->cumulative_tsn_ack_point;
 150 }
 151
 152 /* Retrieve the highest TSN we've seen.  */
 153 static inline __u32 sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap *map)
 154 {
 155         return map->max_tsn_seen;
 156 }
 157
 158 /* How many duplicate TSNs are stored? */
 159 static inline __u16 sctp_tsnmap_num_dups(struct sctp_tsnmap *map)
 160 {
 161         return map->num_dup_tsns;
 162 }
 163
 164 /* Return pointer to duplicate tsn array as needed by SACK. */
 165 static inline __u32 *sctp_tsnmap_get_dups(struct sctp_tsnmap *map)
 166 {
 167         map->num_dup_tsns = 0;
 168         return map->dup_tsns;
 169 }
 170
 171 /* How many gap ack blocks do we have recorded? */
 172 __u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map);
 173
 174 /* Refresh the count on pending data. */
 175 __u16 sctp_tsnmap_pending(struct sctp_tsnmap *map);
 176
 177 /* Return pointer to gap ack blocks as needed by SACK. */
 178 static inline struct sctp_gap_ack_block *sctp_tsnmap_get_gabs(struct sctp_tsnmap *map)
 179 {
 180         return map->gabs;
 181 }
 182
 183 /* Is there a gap in the TSN map?  */
 184 static inline int sctp_tsnmap_has_gap(const struct sctp_tsnmap *map)
 185 {
 186         int has_gap;
 187
 188         has_gap = (map->cumulative_tsn_ack_point != map->max_tsn_seen);
 189         return has_gap;
 190 }
 191
 192 /* Mark a duplicate TSN.  Note:  limit the storage of duplicate TSN
 193  * information.
 194  */
 195 static inline void sctp_tsnmap_mark_dup(struct sctp_tsnmap *map, __u32 tsn)
 196 {
 197         if (map->num_dup_tsns < SCTP_MAX_DUP_TSNS)
 198                 map->dup_tsns[map->num_dup_tsns++] = htonl(tsn);
 199 }
 200
 201 /* Renege a TSN that was seen.  */
 202 void sctp_tsnmap_renege(struct sctp_tsnmap *, __u32 tsn);
 203
 204 /* Is there a gap in the TSN map? */
 205 int sctp_tsnmap_has_gap(const struct sctp_tsnmap *);
 206
 207 #endif /* __sctp_tsnmap_h__ */