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#ifndef _ACKVEC_H
#define _ACKVEC_H
* net/dccp/ackvec.h
* An implementation of the DCCP protocol
* Copyright (c) 2005 Arnaldo Carvalho de Melo <>
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
#include <linux/dccp.h>
#include <linux/compiler.h>
#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/types.h>
/* We can spread an ack vector across multiple options */
/* Estimated minimum average Ack Vector length - used for updating MPS */
#define DCCP_ACKVEC_STATE_MASK 0xC0 /* 11000000 */
#define DCCP_ACKVEC_LEN_MASK 0x3F /* 00111111 */
/** struct dccp_ackvec - ack vector
* This data structure is the one defined in RFC 4340, Appendix A.
* @av_buf_head - circular buffer head
* @av_buf_tail - circular buffer tail
* @av_buf_ackno - ack # of the most recent packet acknowledgeable in the
* buffer (i.e. %av_buf_head)
* @av_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked
* by the buffer with State 0
* Additionally, the HC-Receiver must keep some information about the
* Ack Vectors it has recently sent. For each packet sent carrying an
* Ack Vector, it remembers four variables:
* @av_records - list of dccp_ackvec_record
* @av_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
* @av_time - the time in usecs
* @av_buf - circular buffer of acknowledgeable packets
struct dccp_ackvec {
u64 av_buf_ackno;
struct list_head av_records;
ktime_t av_time;
u16 av_buf_head;
u16 av_vec_len;
u8 av_buf_nonce;
u8 av_ack_nonce;
/** struct dccp_ackvec_record - ack vector record
* ACK vector record as defined in Appendix A of spec.
* The list is sorted by avr_ack_seqno
* @avr_node - node in av_records
* @avr_ack_seqno - sequence number of the packet this record was sent on
* @avr_ack_ackno - sequence number being acknowledged
* @avr_ack_ptr - pointer into av_buf where this record starts
* @avr_ack_nonce - av_ack_nonce at the time this record was sent
* @avr_sent_len - lenght of the record in av_buf
struct dccp_ackvec_record {
struct list_head avr_node;
u64 avr_ack_seqno;
u64 avr_ack_ackno;
u16 avr_ack_ptr;
u16 avr_sent_len;
u8 avr_ack_nonce;
struct sock;
struct sk_buff;
extern int dccp_ackvec_init(void);
extern void dccp_ackvec_exit(void);
extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
extern void dccp_ackvec_free(struct dccp_ackvec *av);
extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
const u64 ackno, const u8 state);
extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
struct sock *sk, const u64 ackno);
extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
u64 *ackno, const u8 opt,
const u8 *value, const u8 len);
extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
return av->av_vec_len;
#endif /* _ACKVEC_H */