ackvec.h (d585a021c0b10b0477d6b608c53e1feb8cde0507) ackvec.h (f17a37c9b8c4b32c01e501a84fa6f30e344c6110)
1#ifndef _ACKVEC_H
2#define _ACKVEC_H
3/*
4 * net/dccp/ackvec.h
5 *
1#ifndef _ACKVEC_H
2#define _ACKVEC_H
3/*
4 * net/dccp/ackvec.h
5 *
6 * An implementation of the DCCP protocol
6 * An implementation of Ack Vectors for the DCCP protocol
7 * Copyright (c) 2007 University of Aberdeen, Scotland, UK
7 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com>
8 * 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>
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
16#include <linux/list.h>
17#include <linux/types.h>
18
20/* We can spread an ack vector across multiple options */
21#define DCCP_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * 2)
19/*
20 * Ack Vector buffer space is static, in multiples of %DCCP_SINGLE_OPT_MAXLEN,
21 * the maximum size of a single Ack Vector. Setting %DCCPAV_NUM_ACKVECS to 1
22 * will be sufficient for most cases of low Ack Ratios, using a value of 2 gives
23 * more headroom if Ack Ratio is higher or when the sender acknowledges slowly.
24 */
25#define DCCPAV_NUM_ACKVECS 2
26#define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS)
22
23/* Estimated minimum average Ack Vector length - used for updating MPS */
24#define DCCPAV_MIN_OPTLEN 16
25
27
28/* Estimated minimum average Ack Vector length - used for updating MPS */
29#define DCCPAV_MIN_OPTLEN 16
30
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)
31enum dccp_ackvec_states {
32 DCCPAV_RECEIVED = 0x00,
33 DCCPAV_ECN_MARKED = 0x40,
34 DCCPAV_RESERVED = 0x80,
35 DCCPAV_NOT_RECEIVED = 0xC0
36};
37#define DCCPAV_MAX_RUNLEN 0x3F
29
38
30#define DCCP_ACKVEC_STATE_MASK 0xC0 /* 11000000 */
31#define DCCP_ACKVEC_LEN_MASK 0x3F /* 00111111 */
39static inline u8 dccp_ackvec_runlen(const u8 *cell)
40{
41 return *cell & DCCPAV_MAX_RUNLEN;
42}
32
43
33/** struct dccp_ackvec - ack vector
44static inline u8 dccp_ackvec_state(const u8 *cell)
45{
46 return *cell & ~DCCPAV_MAX_RUNLEN;
47}
48
49/** struct dccp_ackvec - Ack Vector main data structure
34 *
50 *
35 * This data structure is the one defined in RFC 4340, Appendix A.
51 * This implements a fixed-size circular buffer within an array and is largely
52 * based on Appendix A of RFC 4340.
36 *
53 *
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
54 * @av_buf: circular buffer storage area
55 * @av_buf_head: head index; begin of live portion in @av_buf
56 * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf
57 * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf
58 * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to
59 * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf
60 * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously)
61 * @av_veclen: length of the live portion of @av_buf
53 */
54struct dccp_ackvec {
62 */
63struct dccp_ackvec {
55 u64 av_buf_ackno;
56 struct list_head av_records;
57 ktime_t av_time;
64 u8 av_buf[DCCPAV_MAX_ACKVEC_LEN];
58 u16 av_buf_head;
65 u16 av_buf_head;
66 u16 av_buf_tail;
67 u64 av_buf_ackno:48;
68 bool av_buf_nonce[DCCPAV_NUM_ACKVECS];
69 struct list_head av_records;
59 u16 av_vec_len;
70 u16 av_vec_len;
60 u8 av_buf_nonce;
61 u8 av_ack_nonce;
62 u8 av_buf[DCCP_MAX_ACKVEC_LEN];
63};
64
71};
72
65/** struct dccp_ackvec_record - ack vector record
73/** struct dccp_ackvec_record - Records information about sent Ack Vectors
66 *
74 *
67 * ACK vector record as defined in Appendix A of spec.
75 * These list entries define the additional information which the HC-Receiver
76 * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A.
68 *
77 *
69 * The list is sorted by avr_ack_seqno
78 * @avr_node: the list node in @av_records
79 * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on
80 * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to
81 * @avr_ack_ptr: pointer into @av_buf where this record starts
82 * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending
83 * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent
70 *
84 *
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
85 * The list as a whole is sorted in descending order by @avr_ack_seqno.
77 */
78struct dccp_ackvec_record {
79 struct list_head avr_node;
86 */
87struct dccp_ackvec_record {
88 struct list_head avr_node;
80 u64 avr_ack_seqno;
81 u64 avr_ack_ackno;
89 u64 avr_ack_seqno:48;
90 u64 avr_ack_ackno:48;
82 u16 avr_ack_ptr;
91 u16 avr_ack_ptr;
83 u16 avr_sent_len;
84 u8 avr_ack_nonce;
92 u8 avr_ack_runlen;
93 u8 avr_ack_nonce:1;
85};
86
87struct sock;
88struct sk_buff;
89
90extern int dccp_ackvec_init(void);
91extern void dccp_ackvec_exit(void);
92

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95
96struct sock;
97struct sk_buff;
98
99extern int dccp_ackvec_init(void);
100extern void dccp_ackvec_exit(void);
101

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