1 #ifndef _ACKVEC_H 2 #define _ACKVEC_H 3 /* 4 * net/dccp/ackvec.h 5 * 6 * An implementation of the DCCP protocol 7 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com> 8 * 9 * This program is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 */ 13 14 #include <linux/compiler.h> 15 #include <linux/ktime.h> 16 #include <linux/list.h> 17 #include <linux/types.h> 18 19 /* Read about the ECN nonce to see why it is 253 */ 20 #define DCCP_MAX_ACKVEC_OPT_LEN 253 21 /* We can spread an ack vector across multiple options */ 22 #define DCCP_MAX_ACKVEC_LEN (DCCP_MAX_ACKVEC_OPT_LEN * 2) 23 24 #define DCCP_ACKVEC_STATE_RECEIVED 0 25 #define DCCP_ACKVEC_STATE_ECN_MARKED (1 << 6) 26 #define DCCP_ACKVEC_STATE_NOT_RECEIVED (3 << 6) 27 28 #define DCCP_ACKVEC_STATE_MASK 0xC0 /* 11000000 */ 29 #define DCCP_ACKVEC_LEN_MASK 0x3F /* 00111111 */ 30 31 /** struct dccp_ackvec - ack vector 32 * 33 * This data structure is the one defined in RFC 4340, Appendix A. 34 * 35 * @av_buf_head - circular buffer head 36 * @av_buf_tail - circular buffer tail 37 * @av_buf_ackno - ack # of the most recent packet acknowledgeable in the 38 * buffer (i.e. %av_buf_head) 39 * @av_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked 40 * by the buffer with State 0 41 * 42 * Additionally, the HC-Receiver must keep some information about the 43 * Ack Vectors it has recently sent. For each packet sent carrying an 44 * Ack Vector, it remembers four variables: 45 * 46 * @av_records - list of dccp_ackvec_record 47 * @av_ack_nonce - the one-bit sum of the ECN Nonces for all State 0. 48 * 49 * @av_time - the time in usecs 50 * @av_buf - circular buffer of acknowledgeable packets 51 */ 52 struct dccp_ackvec { 53 u64 av_buf_ackno; 54 struct list_head av_records; 55 ktime_t av_time; 56 u16 av_buf_head; 57 u16 av_vec_len; 58 u8 av_buf_nonce; 59 u8 av_ack_nonce; 60 u8 av_buf[DCCP_MAX_ACKVEC_LEN]; 61 }; 62 63 /** struct dccp_ackvec_record - ack vector record 64 * 65 * ACK vector record as defined in Appendix A of spec. 66 * 67 * The list is sorted by avr_ack_seqno 68 * 69 * @avr_node - node in av_records 70 * @avr_ack_seqno - sequence number of the packet this record was sent on 71 * @avr_ack_ackno - sequence number being acknowledged 72 * @avr_ack_ptr - pointer into av_buf where this record starts 73 * @avr_ack_nonce - av_ack_nonce at the time this record was sent 74 * @avr_sent_len - lenght of the record in av_buf 75 */ 76 struct dccp_ackvec_record { 77 struct list_head avr_node; 78 u64 avr_ack_seqno; 79 u64 avr_ack_ackno; 80 u16 avr_ack_ptr; 81 u16 avr_sent_len; 82 u8 avr_ack_nonce; 83 }; 84 85 struct sock; 86 struct sk_buff; 87 88 #ifdef CONFIG_IP_DCCP_ACKVEC 89 extern int dccp_ackvec_init(void); 90 extern void dccp_ackvec_exit(void); 91 92 extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); 93 extern void dccp_ackvec_free(struct dccp_ackvec *av); 94 95 extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, 96 const u64 ackno, const u8 state); 97 98 extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, 99 struct sock *sk, const u64 ackno); 100 extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, 101 u64 *ackno, const u8 opt, 102 const u8 *value, const u8 len); 103 104 extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb); 105 106 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) 107 { 108 return av->av_vec_len; 109 } 110 #else /* CONFIG_IP_DCCP_ACKVEC */ 111 static inline int dccp_ackvec_init(void) 112 { 113 return 0; 114 } 115 116 static inline void dccp_ackvec_exit(void) 117 { 118 } 119 120 static inline struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority) 121 { 122 return NULL; 123 } 124 125 static inline void dccp_ackvec_free(struct dccp_ackvec *av) 126 { 127 } 128 129 static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, 130 const u64 ackno, const u8 state) 131 { 132 return -1; 133 } 134 135 static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, 136 struct sock *sk, const u64 ackno) 137 { 138 } 139 140 static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, 141 const u64 *ackno, const u8 opt, 142 const u8 *value, const u8 len) 143 { 144 return -1; 145 } 146 147 static inline int dccp_insert_option_ackvec(const struct sock *sk, 148 const struct sk_buff *skb) 149 { 150 return -1; 151 } 152 153 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) 154 { 155 return 0; 156 } 157 #endif /* CONFIG_IP_DCCP_ACKVEC */ 158 #endif /* _ACKVEC_H */ 159