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. */
sctp_tsnmap_get_ctsn(const struct sctp_tsnmap * map)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. */
sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap * map)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? */
sctp_tsnmap_num_dups(struct sctp_tsnmap * map)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. */
sctp_tsnmap_get_dups(struct sctp_tsnmap * map)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. */
sctp_tsnmap_get_gabs(struct sctp_tsnmap * map)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? */
sctp_tsnmap_has_gap(const struct sctp_tsnmap * 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 */
sctp_tsnmap_mark_dup(struct sctp_tsnmap * map,__u32 tsn)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__ */
208