aboutsummaryrefslogtreecommitdiffstats
path: root/net/dccp/ackvec.h
blob: 4ccee030524e403abac5cec98e340307937021b1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
#ifndef _ACKVEC_H
#define _ACKVEC_H
/*
 *  net/dccp/ackvec.h
 *
 *  An implementation of the DCCP protocol
 *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com>
 *
 *	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 */
#define DCCP_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * 2)

#define DCCP_ACKVEC_STATE_RECEIVED	0
#define DCCP_ACKVEC_STATE_ECN_MARKED	(1 << 6)
#define DCCP_ACKVEC_STATE_NOT_RECEIVED	(3 << 6)

#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;
	u8			av_buf[DCCP_MAX_ACKVEC_LEN];
};

/** 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;

#ifdef CONFIG_IP_DCCP_ACKVEC
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;
}
#else /* CONFIG_IP_DCCP_ACKVEC */
static inline int dccp_ackvec_init(void)
{
	return 0;
}

static inline void dccp_ackvec_exit(void)
{
}

static inline struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
{
	return NULL;
}

static inline void dccp_ackvec_free(struct dccp_ackvec *av)
{
}

static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
				  const u64 ackno, const u8 state)
{
	return -1;
}

static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
					       struct sock *sk, const u64 ackno)
{
}

static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
				    const u64 *ackno, const u8 opt,
				    const u8 *value, const u8 len)
{
	return -1;
}

static inline int dccp_insert_option_ackvec(const struct sock *sk,
					    const struct sk_buff *skb)
{
	return -1;
}

static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
{
	return 0;
}
#endif /* CONFIG_IP_DCCP_ACKVEC */
#endif /* _ACKVEC_H */