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 <linux-sctp@vger.kernel.org> 32 * 33 * Written or modified by: 34 * Jon Grimm <jgrimm@us.ibm.com> 35 * La Monte H.P. Yarroll <piggy@acm.org> 36 * Karl Knutson <karl@athena.chicago.il.us> 37 * Sridhar Samudrala <sri@us.ibm.com> 38 */ 39 #include <net/sctp/constants.h> 40 41 #ifndef __sctp_tsnmap_h__ 42 #define __sctp_tsnmap_h__ 43 44 /* RFC 2960 12.2 Parameters necessary per association (i.e. the TCB) 45 * Mapping An array of bits or bytes indicating which out of 46 * Array order TSN's have been received (relative to the 47 * Last Rcvd TSN). If no gaps exist, i.e. no out of 48 * order packets have been received, this array 49 * will be set to all zero. This structure may be 50 * in the form of a circular buffer or bit array. 51 */ 52 struct sctp_tsnmap { 53 /* This array counts the number of chunks with each TSN. 54 * It points at one of the two buffers with which we will 55 * ping-pong between. 56 */ 57 unsigned long *tsn_map; 58 59 /* This is the TSN at tsn_map[0]. */ 60 __u32 base_tsn; 61 62 /* Last Rcvd : This is the last TSN received in 63 * TSN : sequence. This value is set initially by 64 * : taking the peer's Initial TSN, received in 65 * : the INIT or INIT ACK chunk, and subtracting 66 * : one from it. 67 * 68 * Throughout most of the specification this is called the 69 * "Cumulative TSN ACK Point". In this case, we 70 * ignore the advice in 12.2 in favour of the term 71 * used in the bulk of the text. 72 */ 73 __u32 cumulative_tsn_ack_point; 74 75 /* This is the highest TSN we've marked. */ 76 __u32 max_tsn_seen; 77 78 /* This is the minimum number of TSNs we can track. This corresponds 79 * to the size of tsn_map. Note: the overflow_map allows us to 80 * potentially track more than this quantity. 81 */ 82 __u16 len; 83 84 /* Data chunks pending receipt. used by SCTP_STATUS sockopt */ 85 __u16 pending_data; 86 87 /* Record duplicate TSNs here. We clear this after 88 * every SACK. Store up to SCTP_MAX_DUP_TSNS worth of 89 * information. 90 */ 91 __u16 num_dup_tsns; 92 __be32 dup_tsns[SCTP_MAX_DUP_TSNS]; 93 }; 94 95 struct sctp_tsnmap_iter { 96 __u32 start; 97 }; 98 99 /* Initialize a block of memory as a tsnmap. */ 100 struct sctp_tsnmap *sctp_tsnmap_init(struct sctp_tsnmap *, __u16 len, 101 __u32 initial_tsn, gfp_t gfp); 102 103 void sctp_tsnmap_free(struct sctp_tsnmap *map); 104 105 /* Test the tracking state of this TSN. 106 * Returns: 107 * 0 if the TSN has not yet been seen 108 * >0 if the TSN has been seen (duplicate) 109 * <0 if the TSN is invalid (too large to track) 110 */ 111 int sctp_tsnmap_check(const struct sctp_tsnmap *, __u32 tsn); 112 113 /* Mark this TSN as seen. */ 114 int sctp_tsnmap_mark(struct sctp_tsnmap *, __u32 tsn, 115 struct sctp_transport *trans); 116 117 /* Mark this TSN and all lower as seen. */ 118 void sctp_tsnmap_skip(struct sctp_tsnmap *map, __u32 tsn); 119 120 /* Retrieve the Cumulative TSN ACK Point. */ 121 static inline __u32 sctp_tsnmap_get_ctsn(const struct sctp_tsnmap *map) 122 { 123 return map->cumulative_tsn_ack_point; 124 } 125 126 /* Retrieve the highest TSN we've seen. */ 127 static inline __u32 sctp_tsnmap_get_max_tsn_seen(const struct sctp_tsnmap *map) 128 { 129 return map->max_tsn_seen; 130 } 131 132 /* How many duplicate TSNs are stored? */ 133 static inline __u16 sctp_tsnmap_num_dups(struct sctp_tsnmap *map) 134 { 135 return map->num_dup_tsns; 136 } 137 138 /* Return pointer to duplicate tsn array as needed by SACK. */ 139 static inline __be32 *sctp_tsnmap_get_dups(struct sctp_tsnmap *map) 140 { 141 map->num_dup_tsns = 0; 142 return map->dup_tsns; 143 } 144 145 /* How many gap ack blocks do we have recorded? */ 146 __u16 sctp_tsnmap_num_gabs(struct sctp_tsnmap *map, 147 struct sctp_gap_ack_block *gabs); 148 149 /* Refresh the count on pending data. */ 150 __u16 sctp_tsnmap_pending(struct sctp_tsnmap *map); 151 152 /* Is there a gap in the TSN map? */ 153 static inline int sctp_tsnmap_has_gap(const struct sctp_tsnmap *map) 154 { 155 return map->cumulative_tsn_ack_point != map->max_tsn_seen; 156 } 157 158 /* Mark a duplicate TSN. Note: limit the storage of duplicate TSN 159 * information. 160 */ 161 static inline void sctp_tsnmap_mark_dup(struct sctp_tsnmap *map, __u32 tsn) 162 { 163 if (map->num_dup_tsns < SCTP_MAX_DUP_TSNS) 164 map->dup_tsns[map->num_dup_tsns++] = htonl(tsn); 165 } 166 167 /* Renege a TSN that was seen. */ 168 void sctp_tsnmap_renege(struct sctp_tsnmap *, __u32 tsn); 169 170 /* Is there a gap in the TSN map? */ 171 int sctp_tsnmap_has_gap(const struct sctp_tsnmap *); 172 173 #endif /* __sctp_tsnmap_h__ */ 174