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. */
sctp_tsnmap_get_ctsn(const struct sctp_tsnmap * map)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. */
sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap * map)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? */
sctp_tsnmap_num_dups(struct sctp_tsnmap * map)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. */
sctp_tsnmap_get_dups(struct sctp_tsnmap * map)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? */
sctp_tsnmap_has_gap(const struct sctp_tsnmap * 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 */
sctp_tsnmap_mark_dup(struct sctp_tsnmap * map,__u32 tsn)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__ */
179