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__ */ |
158 | |