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1#ifndef _ACKVEC_H
2#define _ACKVEC_H
3/*
4 * net/dccp/ackvec.h
5 *
6 * An implementation of Ack Vectors for the DCCP protocol
7 * Copyright (c) 2007 University of Aberdeen, Scotland, UK
8 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com>
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/list.h>
17#include <linux/types.h>
18
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 * The maximum value is bounded by the u16 types for indices and functions.
25 */
26#define DCCPAV_NUM_ACKVECS 2
27#define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS)
28
29/* Estimated minimum average Ack Vector length - used for updating MPS */
30#define DCCPAV_MIN_OPTLEN 16
31
32/* Threshold for coping with large bursts of losses */
33#define DCCPAV_BURST_THRESH (DCCPAV_MAX_ACKVEC_LEN / 8)
34
35enum dccp_ackvec_states {
36 DCCPAV_RECEIVED = 0x00,
37 DCCPAV_ECN_MARKED = 0x40,
38 DCCPAV_RESERVED = 0x80,
39 DCCPAV_NOT_RECEIVED = 0xC0
40};
41#define DCCPAV_MAX_RUNLEN 0x3F
42
43static inline u8 dccp_ackvec_runlen(const u8 *cell)
44{
45 return *cell & DCCPAV_MAX_RUNLEN;
46}
47
48static inline u8 dccp_ackvec_state(const u8 *cell)
49{
50 return *cell & ~DCCPAV_MAX_RUNLEN;
51}
52
53/**
54 * struct dccp_ackvec - Ack Vector main data structure
55 *
56 * This implements a fixed-size circular buffer within an array and is largely
57 * based on Appendix A of RFC 4340.
58 *
59 * @av_buf: circular buffer storage area
60 * @av_buf_head: head index; begin of live portion in @av_buf
61 * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf
62 * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf
63 * @av_tail_ackno: lowest seqno of acknowledgeable packet recorded in @av_buf
64 * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to
65 * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf
66 * @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound
67 * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously)
68 */
69struct dccp_ackvec {
70 u8 av_buf[DCCPAV_MAX_ACKVEC_LEN];
71 u16 av_buf_head;
72 u16 av_buf_tail;
73 u64 av_buf_ackno:48;
74 u64 av_tail_ackno:48;
75 bool av_buf_nonce[DCCPAV_NUM_ACKVECS];
76 u8 av_overflow:1;
77 struct list_head av_records;
78};
79
80/**
81 * struct dccp_ackvec_record - Records information about sent Ack Vectors
82 *
83 * These list entries define the additional information which the HC-Receiver
84 * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A.
85 *
86 * @avr_node: the list node in @av_records
87 * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on
88 * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to
89 * @avr_ack_ptr: pointer into @av_buf where this record starts
90 * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending
91 * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent
92 *
93 * The list as a whole is sorted in descending order by @avr_ack_seqno.
94 */
95struct dccp_ackvec_record {
96 struct list_head avr_node;
97 u64 avr_ack_seqno:48;
98 u64 avr_ack_ackno:48;
99 u16 avr_ack_ptr;
100 u8 avr_ack_runlen;
101 u8 avr_ack_nonce:1;
102};
103
104int dccp_ackvec_init(void);
105void dccp_ackvec_exit(void);
106
107struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
108void dccp_ackvec_free(struct dccp_ackvec *av);
109
110void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb);
111int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum);
112void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno);
113u16 dccp_ackvec_buflen(const struct dccp_ackvec *av);
114
115static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av)
116{
117 return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail;
118}
119
120/**
121 * struct dccp_ackvec_parsed - Record offsets of Ack Vectors in skb
122 * @vec: start of vector (offset into skb)
123 * @len: length of @vec
124 * @nonce: whether @vec had an ECN nonce of 0 or 1
125 * @node: FIFO - arranged in descending order of ack_ackno
126 *
127 * This structure is used by CCIDs to access Ack Vectors in a received skb.
128 */
129struct dccp_ackvec_parsed {
130 u8 *vec,
131 len,
132 nonce:1;
133 struct list_head node;
134};
135
136int dccp_ackvec_parsed_add(struct list_head *head, u8 *vec, u8 len, u8 nonce);
137void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks);
138#endif /* _ACKVEC_H */
1/* SPDX-License-Identifier: GPL-2.0-only */
2#ifndef _ACKVEC_H
3#define _ACKVEC_H
4/*
5 * net/dccp/ackvec.h
6 *
7 * An implementation of Ack Vectors for the DCCP protocol
8 * Copyright (c) 2007 University of Aberdeen, Scotland, UK
9 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com>
10 */
11
12#include <linux/dccp.h>
13#include <linux/compiler.h>
14#include <linux/list.h>
15#include <linux/types.h>
16
17/*
18 * Ack Vector buffer space is static, in multiples of %DCCP_SINGLE_OPT_MAXLEN,
19 * the maximum size of a single Ack Vector. Setting %DCCPAV_NUM_ACKVECS to 1
20 * will be sufficient for most cases of low Ack Ratios, using a value of 2 gives
21 * more headroom if Ack Ratio is higher or when the sender acknowledges slowly.
22 * The maximum value is bounded by the u16 types for indices and functions.
23 */
24#define DCCPAV_NUM_ACKVECS 2
25#define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS)
26
27/* Estimated minimum average Ack Vector length - used for updating MPS */
28#define DCCPAV_MIN_OPTLEN 16
29
30/* Threshold for coping with large bursts of losses */
31#define DCCPAV_BURST_THRESH (DCCPAV_MAX_ACKVEC_LEN / 8)
32
33enum dccp_ackvec_states {
34 DCCPAV_RECEIVED = 0x00,
35 DCCPAV_ECN_MARKED = 0x40,
36 DCCPAV_RESERVED = 0x80,
37 DCCPAV_NOT_RECEIVED = 0xC0
38};
39#define DCCPAV_MAX_RUNLEN 0x3F
40
41static inline u8 dccp_ackvec_runlen(const u8 *cell)
42{
43 return *cell & DCCPAV_MAX_RUNLEN;
44}
45
46static inline u8 dccp_ackvec_state(const u8 *cell)
47{
48 return *cell & ~DCCPAV_MAX_RUNLEN;
49}
50
51/**
52 * struct dccp_ackvec - Ack Vector main data structure
53 *
54 * This implements a fixed-size circular buffer within an array and is largely
55 * based on Appendix A of RFC 4340.
56 *
57 * @av_buf: circular buffer storage area
58 * @av_buf_head: head index; begin of live portion in @av_buf
59 * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf
60 * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf
61 * @av_tail_ackno: lowest seqno of acknowledgeable packet recorded in @av_buf
62 * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to
63 * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf
64 * @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound
65 * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously)
66 */
67struct dccp_ackvec {
68 u8 av_buf[DCCPAV_MAX_ACKVEC_LEN];
69 u16 av_buf_head;
70 u16 av_buf_tail;
71 u64 av_buf_ackno:48;
72 u64 av_tail_ackno:48;
73 bool av_buf_nonce[DCCPAV_NUM_ACKVECS];
74 u8 av_overflow:1;
75 struct list_head av_records;
76};
77
78/**
79 * struct dccp_ackvec_record - Records information about sent Ack Vectors
80 *
81 * These list entries define the additional information which the HC-Receiver
82 * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A.
83 *
84 * @avr_node: the list node in @av_records
85 * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on
86 * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to
87 * @avr_ack_ptr: pointer into @av_buf where this record starts
88 * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending
89 * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent
90 *
91 * The list as a whole is sorted in descending order by @avr_ack_seqno.
92 */
93struct dccp_ackvec_record {
94 struct list_head avr_node;
95 u64 avr_ack_seqno:48;
96 u64 avr_ack_ackno:48;
97 u16 avr_ack_ptr;
98 u8 avr_ack_runlen;
99 u8 avr_ack_nonce:1;
100};
101
102int dccp_ackvec_init(void);
103void dccp_ackvec_exit(void);
104
105struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
106void dccp_ackvec_free(struct dccp_ackvec *av);
107
108void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb);
109int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum);
110void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno);
111u16 dccp_ackvec_buflen(const struct dccp_ackvec *av);
112
113static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av)
114{
115 return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail;
116}
117
118/**
119 * struct dccp_ackvec_parsed - Record offsets of Ack Vectors in skb
120 * @vec: start of vector (offset into skb)
121 * @len: length of @vec
122 * @nonce: whether @vec had an ECN nonce of 0 or 1
123 * @node: FIFO - arranged in descending order of ack_ackno
124 *
125 * This structure is used by CCIDs to access Ack Vectors in a received skb.
126 */
127struct dccp_ackvec_parsed {
128 u8 *vec,
129 len,
130 nonce:1;
131 struct list_head node;
132};
133
134int dccp_ackvec_parsed_add(struct list_head *head, u8 *vec, u8 len, u8 nonce);
135void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks);
136#endif /* _ACKVEC_H */