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, see
  26  * <http://www.gnu.org/licenses/>.
  27  *
  28  * Please send any bug reports or fixes you make to the
  29  * email address(es):
  30  *    lksctp developers <linux-sctp@vger.kernel.org>
  31  *
  32  * Written or modified by:
  33  *   Jon Grimm             <jgrimm@us.ibm.com>
  34  *   La Monte H.P. Yarroll <piggy@acm.org>
  35  *   Karl Knutson          <karl@athena.chicago.il.us>
  36  *   Sridhar Samudrala     <sri@us.ibm.com>
  37  */
  38 #include <net/sctp/constants.h>
  39
  40 #ifndef __sctp_tsnmap_h__
  41 #define __sctp_tsnmap_h__
  42
  43 /* RFC 2960 12.2 Parameters necessary per association (i.e. the TCB)
  44  * Mapping  An array of bits or bytes indicating which out of
  45  * Array    order TSN's have been received (relative to the
  46  *          Last Rcvd TSN). If no gaps exist, i.e. no out of
  47  *          order packets have been received, this array
  48  *          will be set to all zero. This structure may be
  49  *          in the form of a circular buffer or bit array.
  50  */
  51 struct sctp_tsnmap {
  52         /* This array counts the number of chunks with each TSN.
  53          * It points at one of the two buffers with which we will
  54          * ping-pong between.
  55          */
  56         unsigned long *tsn_map;
  57
  58         /* This is the TSN at tsn_map[0].  */
  59         __u32 base_tsn;
  60
  61         /* Last Rcvd   : This is the last TSN received in
  62          * TSN         : sequence. This value is set initially by
  63          *             : taking the peer's Initial TSN, received in
  64          *             : the INIT or INIT ACK chunk, and subtracting
  65          *             : one from it.
  66          *
  67          * Throughout most of the specification this is called the
  68          * "Cumulative TSN ACK Point".  In this case, we
  69          * ignore the advice in 12.2 in favour of the term
  70          * used in the bulk of the text.
  71          */
  72         __u32 cumulative_tsn_ack_point;
  73
  74         /* This is the highest TSN we've marked.  */
  75         __u32 max_tsn_seen;
  76
  77         /* This is the minimum number of TSNs we can track.  This corresponds
  78          * to the size of tsn_map.   Note: the overflow_map allows us to
  79          * potentially track more than this quantity.
  80          */
  81         __u16 len;
  82
  83         /* Data chunks pending receipt. used by SCTP_STATUS sockopt */
  84         __u16 pending_data;
  85
  86         /* Record duplicate TSNs here.  We clear this after
  87          * every SACK.  Store up to SCTP_MAX_DUP_TSNS worth of
  88          * information.
  89          */
  90         __u16 num_dup_tsns;
  91         __be32 dup_tsns[SCTP_MAX_DUP_TSNS];
  92 };
  93
  94 struct sctp_tsnmap_iter {
  95         __u32 start;
  96 };
  97
  98 /* Initialize a block of memory as a tsnmap.  */
  99 struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *, __u16 len,
 100                                      __u32 initial_tsn, gfp_t gfp);
 101
 102 void sctp_tsnmap_free(struct sctp_tsnmap *map);
 103
 104 /* Test the tracking state of this TSN.
 105  * Returns:
 106  *   0 if the TSN has not yet been seen
 107  *  >0 if the TSN has been seen (duplicate)
 108  *  <0 if the TSN is invalid (too large to track)
 109  */
 110 int sctp_tsnmap_check(const struct sctp_tsnmap *, __u32 tsn);
 111
 112 /* Mark this TSN as seen.  */
 113 int sctp_tsnmap_mark(struct sctp_tsnmap *, __u32 tsn,
 114                      struct sctp_transport *trans);
 115
 116 /* Mark this TSN and all lower as seen. */
 117 void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn);
 118
 119 /* Retrieve the Cumulative TSN ACK Point.  */
 120 static inline __u32 sctp_tsnmap_get_ctsn(const struct sctp_tsnmap *map)
 121 {
 122         return map->cumulative_tsn_ack_point;
 123 }
 124
 125 /* Retrieve the highest TSN we've seen.  */
 126 static inline __u32 sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap *map)
 127 {
 128         return map->max_tsn_seen;
 129 }
 130
 131 /* How many duplicate TSNs are stored? */
 132 static inline __u16 sctp_tsnmap_num_dups(struct sctp_tsnmap *map)
 133 {
 134         return map->num_dup_tsns;
 135 }
 136
 137 /* Return pointer to duplicate tsn array as needed by SACK. */
 138 static inline __be32 *sctp_tsnmap_get_dups(struct sctp_tsnmap *map)
 139 {
 140         map->num_dup_tsns = 0;
 141         return map->dup_tsns;
 142 }
 143
 144 /* How many gap ack blocks do we have recorded? */
 145 __u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
 146                            struct sctp_gap_ack_block *gabs);
 147
 148 /* Refresh the count on pending data. */
 149 __u16 sctp_tsnmap_pending(struct sctp_tsnmap *map);
 150
 151 /* Is there a gap in the TSN map?  */
 152 static inline int sctp_tsnmap_has_gap(const struct sctp_tsnmap *map)
 153 {
 154         return map->cumulative_tsn_ack_point != map->max_tsn_seen;
 155 }
 156
 157 /* Mark a duplicate TSN.  Note:  limit the storage of duplicate TSN
 158  * information.
 159  */
 160 static inline void sctp_tsnmap_mark_dup(struct sctp_tsnmap *map, __u32 tsn)
 161 {
 162         if (map->num_dup_tsns < SCTP_MAX_DUP_TSNS)
 163                 map->dup_tsns[map->num_dup_tsns++] = htonl(tsn);
 164 }
 165
 166 /* Renege a TSN that was seen.  */
 167 void sctp_tsnmap_renege(struct sctp_tsnmap *, __u32 tsn);
 168
 169 /* Is there a gap in the TSN map? */
 170 int sctp_tsnmap_has_gap(const struct sctp_tsnmap *);
 171
 172 #endif /* __sctp_tsnmap_h__ */