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1#ifndef _ACKVEC_H
2#define _ACKVEC_H
3/*
4 * net/dccp/ackvec.h
5 *
6 * An implementation of the DCCP protocol
7 * 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/config.h>
15#include <linux/compiler.h>
16#include <linux/time.h>
17#include <linux/types.h>
18
19/* Read about the ECN nonce to see why it is 253 */
20#define DCCP_MAX_ACKVEC_LEN 253
21
22#define DCCP_ACKVEC_STATE_RECEIVED 0
23#define DCCP_ACKVEC_STATE_ECN_MARKED (1 << 6)
24#define DCCP_ACKVEC_STATE_NOT_RECEIVED (3 << 6)
25
26#define DCCP_ACKVEC_STATE_MASK 0xC0 /* 11000000 */
27#define DCCP_ACKVEC_LEN_MASK 0x3F /* 00111111 */
28
29/** struct dccp_ackvec - ack vector
30 *
31 * This data structure is the one defined in the DCCP draft
32 * Appendix A.
33 *
34 * @dccpav_buf_head - circular buffer head
35 * @dccpav_buf_tail - circular buffer tail
36 * @dccpav_buf_ackno - ack # of the most recent packet acknowledgeable in the
37 * buffer (i.e. %dccpav_buf_head)
38 * @dccpav_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked
39 * by the buffer with State 0
40 *
41 * Additionally, the HC-Receiver must keep some information about the
42 * Ack Vectors it has recently sent. For each packet sent carrying an
43 * Ack Vector, it remembers four variables:
44 *
45 * @dccpav_ack_seqno - the Sequence Number used for the packet
46 * (HC-Receiver seqno)
47 * @dccpav_ack_ptr - the value of buf_head at the time of acknowledgement.
48 * @dccpav_ack_ackno - the Acknowledgement Number used for the packet
49 * (HC-Sender seqno)
50 * @dccpav_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
51 *
52 * @dccpav_buf_len - circular buffer length
53 * @dccpav_time - the time in usecs
54 * @dccpav_buf - circular buffer of acknowledgeable packets
55 */
56struct dccp_ackvec {
57 unsigned int dccpav_buf_head;
58 unsigned int dccpav_buf_tail;
59 u64 dccpav_buf_ackno;
60 u64 dccpav_ack_seqno;
61 u64 dccpav_ack_ackno;
62 unsigned int dccpav_ack_ptr;
63 unsigned int dccpav_sent_len;
64 unsigned int dccpav_vec_len;
65 unsigned int dccpav_buf_len;
66 struct timeval dccpav_time;
67 u8 dccpav_buf_nonce;
68 u8 dccpav_ack_nonce;
69 u8 dccpav_buf[0];
70};
71
72struct sock;
73struct sk_buff;
74
75#ifdef CONFIG_IP_DCCP_ACKVEC
76extern struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len,
77 const gfp_t priority);
78extern void dccp_ackvec_free(struct dccp_ackvec *av);
79
80extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
81 const u64 ackno, const u8 state);
82
83extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
84 struct sock *sk, const u64 ackno);
85extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
86 const u8 opt, const u8 *value, const u8 len);
87
88extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
89
90static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
91{
92 return av->dccpav_sent_len != av->dccpav_vec_len;
93}
94#else /* CONFIG_IP_DCCP_ACKVEC */
95static inline struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len,
96 const gfp_t priority)
97{
98 return NULL;
99}
100
101static inline void dccp_ackvec_free(struct dccp_ackvec *av)
102{
103}
104
105static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
106 const u64 ackno, const u8 state)
107{
108 return -1;
109}
110
111static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
112 struct sock *sk, const u64 ackno)
113{
114}
115
116static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
117 const u8 opt, const u8 *value, const u8 len)
118{
119 return -1;
120}
121
122static inline int dccp_insert_option_ackvec(const struct sock *sk,
123 const struct sk_buff *skb)
124{
125 return -1;
126}
127
128static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
129{
130 return 0;
131}
132#endif /* CONFIG_IP_DCCP_ACKVEC */
133#endif /* _ACKVEC_H */