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. */
sctp_tsnmap_get_ctsn(const struct sctp_tsnmap * map)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. */
sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap * map)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? */
sctp_tsnmap_num_dups(struct sctp_tsnmap * map)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. */
sctp_tsnmap_get_dups(struct sctp_tsnmap * map)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? */
sctp_tsnmap_has_gap(const struct sctp_tsnmap * 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 */
sctp_tsnmap_mark_dup(struct sctp_tsnmap * map,__u32 tsn)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__ */
173