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/dccp.h> 15 #include <linux/compiler.h> 16 #include <linux/ktime.h> 17 #include <linux/list.h> 18 #include <linux/types.h> 19 20 /* We can spread an ack vector across multiple options */ 21 #define DCCP_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * 2) 22 23 /* Estimated minimum average Ack Vector length - used for updating MPS */ 24 #define DCCPAV_MIN_OPTLEN 16 25 26 #define DCCP_ACKVEC_STATE_RECEIVED 0 27 #define DCCP_ACKVEC_STATE_ECN_MARKED (1 << 6) 28 #define DCCP_ACKVEC_STATE_NOT_RECEIVED (3 << 6) 29 30 #define DCCP_ACKVEC_STATE_MASK 0xC0 /* 11000000 */ 31 #define DCCP_ACKVEC_LEN_MASK 0x3F /* 00111111 */ 32 33 /** struct dccp_ackvec - ack vector 34 * 35 * This data structure is the one defined in RFC 4340, Appendix A. 36 * 37 * @av_buf_head - circular buffer head 38 * @av_buf_tail - circular buffer tail 39 * @av_buf_ackno - ack # of the most recent packet acknowledgeable in the 40 * buffer (i.e. %av_buf_head) 41 * @av_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked 42 * by the buffer with State 0 43 * 44 * Additionally, the HC-Receiver must keep some information about the 45 * Ack Vectors it has recently sent. For each packet sent carrying an 46 * Ack Vector, it remembers four variables: 47 * 48 * @av_records - list of dccp_ackvec_record 49 * @av_ack_nonce - the one-bit sum of the ECN Nonces for all State 0. 50 * 51 * @av_time - the time in usecs 52 * @av_buf - circular buffer of acknowledgeable packets 53 */ 54 struct dccp_ackvec { 55 u64 av_buf_ackno; 56 struct list_head av_records; 57 ktime_t av_time; 58 u16 av_buf_head; 59 u16 av_vec_len; 60 u8 av_buf_nonce; 61 u8 av_ack_nonce; 62 u8 av_buf[DCCP_MAX_ACKVEC_LEN]; 63 }; 64 65 /** struct dccp_ackvec_record - ack vector record 66 * 67 * ACK vector record as defined in Appendix A of spec. 68 * 69 * The list is sorted by avr_ack_seqno 70 * 71 * @avr_node - node in av_records 72 * @avr_ack_seqno - sequence number of the packet this record was sent on 73 * @avr_ack_ackno - sequence number being acknowledged 74 * @avr_ack_ptr - pointer into av_buf where this record starts 75 * @avr_ack_nonce - av_ack_nonce at the time this record was sent 76 * @avr_sent_len - lenght of the record in av_buf 77 */ 78 struct dccp_ackvec_record { 79 struct list_head avr_node; 80 u64 avr_ack_seqno; 81 u64 avr_ack_ackno; 82 u16 avr_ack_ptr; 83 u16 avr_sent_len; 84 u8 avr_ack_nonce; 85 }; 86 87 struct sock; 88 struct sk_buff; 89 90 extern int dccp_ackvec_init(void); 91 extern void dccp_ackvec_exit(void); 92 93 extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); 94 extern void dccp_ackvec_free(struct dccp_ackvec *av); 95 96 extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, 97 const u64 ackno, const u8 state); 98 99 extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, 100 struct sock *sk, const u64 ackno); 101 extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, 102 u64 *ackno, const u8 opt, 103 const u8 *value, const u8 len); 104 105 extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb); 106 107 static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) 108 { 109 return av->av_vec_len; 110 } 111 #endif /* _ACKVEC_H */ 112