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, 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 __be32 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. */ 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. */ 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? */ 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. */ 165 static inline __be32 *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. */ 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? */ 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 */ 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