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. */ 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. */ 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? */ 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. */ 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? */ 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 */ 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