aboutsummaryrefslogtreecommitdiffstats
path: root/net/dccp/ackvec.h
blob: 8ca51c9191f7d28bdbdbfdca1fe12b83287df90a (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
#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/config.h>
#include <linux/compiler.h>
#include <linux/time.h>
#include <linux/types.h>

/* Read about the ECN nonce to see why it is 253 */
#define DCCP_MAX_ACKVEC_LEN 253

#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 the DCCP draft
 * Appendix A.
 *
 * @dccpav_buf_head - circular buffer head
 * @dccpav_buf_tail - circular buffer tail
 * @dccpav_buf_ackno - ack # of the most recent packet acknowledgeable in the
 * 		       buffer (i.e. %dccpav_buf_head)
 * @dccpav_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:
 *
 * @dccpav_ack_seqno - the Sequence Number used for the packet
 * 		       (HC-Receiver seqno)
 * @dccpav_ack_ptr - the value of buf_head at the time of acknowledgement.
 * @dccpav_ack_ackno - the Acknowledgement Number used for the packet
 * 		       (HC-Sender seqno)
 * @dccpav_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
 *
 * @dccpav_buf_len	- circular buffer length
 * @dccpav_time		- the time in usecs
 * @dccpav_buf - circular buffer of acknowledgeable packets
 */
struct dccp_ackvec {
	unsigned int	dccpav_buf_head;
	unsigned int	dccpav_buf_tail;
	u64		dccpav_buf_ackno;
	u64		dccpav_ack_seqno;
	u64		dccpav_ack_ackno;
	unsigned int	dccpav_ack_ptr;
	unsigned int	dccpav_sent_len;
	unsigned int	dccpav_vec_len;
	unsigned int	dccpav_buf_len;
	struct timeval	dccpav_time;
	u8		dccpav_buf_nonce;
	u8		dccpav_ack_nonce;
	u8		dccpav_buf[0];
};

struct sock;
struct sk_buff;

#ifdef CONFIG_IP_DCCP_ACKVEC
extern struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len,
					  const unsigned int __nocast 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,
			     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->dccpav_sent_len != av->dccpav_vec_len;
}
#else /* CONFIG_IP_DCCP_ACKVEC */
static inline struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len,
					   const unsigned int __nocast 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 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 */