1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* SCTP kernel implementation
3 * (C) Copyright IBM Corp. 2001, 2004
4 * Copyright (c) 1999-2000 Cisco, Inc.
5 * Copyright (c) 1999-2001 Motorola, Inc.
6 * Copyright (c) 2001 Intel Corp.
7 *
8 * This file is part of the SCTP kernel implementation
9 *
10 * These are the definitions needed for the tsnmap type. The tsnmap is used
11 * to track out of order TSNs received.
12 *
13 * Please send any bug reports or fixes you make to the
14 * email address(es):
15 * lksctp developers <linux-sctp@vger.kernel.org>
16 *
17 * Written or modified by:
18 * Jon Grimm <jgrimm@us.ibm.com>
19 * La Monte H.P. Yarroll <piggy@acm.org>
20 * Karl Knutson <karl@athena.chicago.il.us>
21 * Sridhar Samudrala <sri@us.ibm.com>
22 */
23 #include <net/sctp/constants.h>
24
25 #ifndef __sctp_tsnmap_h__
26 #define __sctp_tsnmap_h__
27
28 /* RFC 2960 12.2 Parameters necessary per association (i.e. the TCB)
29 * Mapping An array of bits or bytes indicating which out of
30 * Array order TSN's have been received (relative to the
31 * Last Rcvd TSN). If no gaps exist, i.e. no out of
32 * order packets have been received, this array
33 * will be set to all zero. This structure may be
34 * in the form of a circular buffer or bit array.
35 */
36 struct sctp_tsnmap {
37 /* This array counts the number of chunks with each TSN.
38 * It points at one of the two buffers with which we will
39 * ping-pong between.
40 */
41 unsigned long *tsn_map;
42
43 /* This is the TSN at tsn_map[0]. */
44 __u32 base_tsn;
45
46 /* Last Rcvd : This is the last TSN received in
47 * TSN : sequence. This value is set initially by
48 * : taking the peer's Initial TSN, received in
49 * : the INIT or INIT ACK chunk, and subtracting
50 * : one from it.
51 *
52 * Throughout most of the specification this is called the
53 * "Cumulative TSN ACK Point". In this case, we
54 * ignore the advice in 12.2 in favour of the term
55 * used in the bulk of the text.
56 */
57 __u32 cumulative_tsn_ack_point;
58
59 /* This is the highest TSN we've marked. */
60 __u32 max_tsn_seen;
61
62 /* This is the minimum number of TSNs we can track. This corresponds
63 * to the size of tsn_map. Note: the overflow_map allows us to
64 * potentially track more than this quantity.
65 */
66 __u16 len;
67
68 /* Data chunks pending receipt. used by SCTP_STATUS sockopt */
69 __u16 pending_data;
70
71 /* Record duplicate TSNs here. We clear this after
72 * every SACK. Store up to SCTP_MAX_DUP_TSNS worth of
73 * information.
74 */
75 __u16 num_dup_tsns;
76 __be32 dup_tsns[SCTP_MAX_DUP_TSNS];
77 };
78
79 struct sctp_tsnmap_iter {
80 __u32 start;
81 };
82
83 /* Initialize a block of memory as a tsnmap. */
84 struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *, __u16 len,
85 __u32 initial_tsn, gfp_t gfp);
86
87 void sctp_tsnmap_free(struct sctp_tsnmap *map);
88
89 /* Test the tracking state of this TSN.
90 * Returns:
91 * 0 if the TSN has not yet been seen
92 * >0 if the TSN has been seen (duplicate)
93 * <0 if the TSN is invalid (too large to track)
94 */
95 int sctp_tsnmap_check(const struct sctp_tsnmap *, __u32 tsn);
96
97 /* Mark this TSN as seen. */
98 int sctp_tsnmap_mark(struct sctp_tsnmap *, __u32 tsn,
99 struct sctp_transport *trans);
100
101 /* Mark this TSN and all lower as seen. */
102 void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn);
103
104 /* Retrieve the Cumulative TSN ACK Point. */
105 static inline __u32 sctp_tsnmap_get_ctsn(const struct sctp_tsnmap *map)
106 {
107 return map->cumulative_tsn_ack_point;
108 }
109
110 /* Retrieve the highest TSN we've seen. */
111 static inline __u32 sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap *map)
112 {
113 return map->max_tsn_seen;
114 }
115
116 /* How many duplicate TSNs are stored? */
117 static inline __u16 sctp_tsnmap_num_dups(struct sctp_tsnmap *map)
118 {
119 return map->num_dup_tsns;
120 }
121
122 /* Return pointer to duplicate tsn array as needed by SACK. */
123 static inline __be32 *sctp_tsnmap_get_dups(struct sctp_tsnmap *map)
124 {
125 map->num_dup_tsns = 0;
126 return map->dup_tsns;
127 }
128
129 /* How many gap ack blocks do we have recorded? */
130 __u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map,
131 struct sctp_gap_ack_block *gabs);
132
133 /* Refresh the count on pending data. */
134 __u16 sctp_tsnmap_pending(struct sctp_tsnmap *map);
135
136 /* Is there a gap in the TSN map? */
137 static inline int sctp_tsnmap_has_gap(const struct sctp_tsnmap *map)
138 {
139 return map->cumulative_tsn_ack_point != map->max_tsn_seen;
140 }
141
142 /* Mark a duplicate TSN. Note: limit the storage of duplicate TSN
143 * information.
144 */
145 static inline void sctp_tsnmap_mark_dup(struct sctp_tsnmap *map, __u32 tsn)
146 {
147 if (map->num_dup_tsns < SCTP_MAX_DUP_TSNS)
148 map->dup_tsns[map->num_dup_tsns++] = htonl(tsn);
149 }
150
151 /* Renege a TSN that was seen. */
152 void sctp_tsnmap_renege(struct sctp_tsnmap *, __u32 tsn);
153
154 /* Is there a gap in the TSN map? */
155 int sctp_tsnmap_has_gap(const struct sctp_tsnmap *);
156
157 #endif /* __sctp_tsnmap_h__ */