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/compiler.h>
15#include <linux/list.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_OPT_LEN 253
21/* We can spread an ack vector across multiple options */
22#define DCCP_MAX_ACKVEC_LEN (DCCP_MAX_ACKVEC_OPT_LEN * 2)
23
24#define DCCP_ACKVEC_STATE_RECEIVED	0
25#define DCCP_ACKVEC_STATE_ECN_MARKED	(1 << 6)
26#define DCCP_ACKVEC_STATE_NOT_RECEIVED	(3 << 6)
27
28#define DCCP_ACKVEC_STATE_MASK		0xC0 /* 11000000 */
29#define DCCP_ACKVEC_LEN_MASK		0x3F /* 00111111 */
30
31/** struct dccp_ackvec - ack vector
32 *
33 * This data structure is the one defined in RFC 4340, Appendix A.
34 *
35 * @dccpav_buf_head - circular buffer head
36 * @dccpav_buf_tail - circular buffer tail
37 * @dccpav_buf_ackno - ack # of the most recent packet acknowledgeable in the
38 * 		       buffer (i.e. %dccpav_buf_head)
39 * @dccpav_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked
40 * 		       by the buffer with State 0
41 *
42 * Additionally, the HC-Receiver must keep some information about the
43 * Ack Vectors it has recently sent. For each packet sent carrying an
44 * Ack Vector, it remembers four variables:
45 *
46 * @dccpav_records - list of dccp_ackvec_record
47 * @dccpav_ack_nonce - the one-bit sum of the ECN Nonces for all State 0.
48 *
49 * @dccpav_time		- the time in usecs
50 * @dccpav_buf - circular buffer of acknowledgeable packets
51 */
52struct dccp_ackvec {
53	u64		dccpav_buf_ackno;
54	struct list_head dccpav_records;
55	struct timeval	dccpav_time;
56	u16		dccpav_buf_head;
57	u16		dccpav_vec_len;
58	u8		dccpav_buf_nonce;
59	u8		dccpav_ack_nonce;
60	u8		dccpav_buf[DCCP_MAX_ACKVEC_LEN];
61};
62
63/** struct dccp_ackvec_record - ack vector record
64 *
65 * ACK vector record as defined in Appendix A of spec.
66 *
67 * The list is sorted by dccpavr_ack_seqno
68 *
69 * @dccpavr_node - node in dccpav_records
70 * @dccpavr_ack_seqno - sequence number of the packet this record was sent on
71 * @dccpavr_ack_ackno - sequence number being acknowledged
72 * @dccpavr_ack_ptr - pointer into dccpav_buf where this record starts
73 * @dccpavr_ack_nonce - dccpav_ack_nonce at the time this record was sent
74 * @dccpavr_sent_len - lenght of the record in dccpav_buf
75 */
76struct dccp_ackvec_record {
77	struct list_head dccpavr_node;
78	u64		 dccpavr_ack_seqno;
79	u64		 dccpavr_ack_ackno;
80	u16		 dccpavr_ack_ptr;
81	u16		 dccpavr_sent_len;
82	u8		 dccpavr_ack_nonce;
83};
84
85struct sock;
86struct sk_buff;
87
88#ifdef CONFIG_IP_DCCP_ACKVEC
89extern int dccp_ackvec_init(void);
90extern void dccp_ackvec_exit(void);
91
92extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
93extern void dccp_ackvec_free(struct dccp_ackvec *av);
94
95extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
96			   const u64 ackno, const u8 state);
97
98extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
99					struct sock *sk, const u64 ackno);
100extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
101			     u64 *ackno, const u8 opt,
102			     const u8 *value, const u8 len);
103
104extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
105
106static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
107{
108	return av->dccpav_vec_len;
109}
110#else /* CONFIG_IP_DCCP_ACKVEC */
111static inline int dccp_ackvec_init(void)
112{
113	return 0;
114}
115
116static inline void dccp_ackvec_exit(void)
117{
118}
119
120static inline struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority)
121{
122	return NULL;
123}
124
125static inline void dccp_ackvec_free(struct dccp_ackvec *av)
126{
127}
128
129static inline int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
130				  const u64 ackno, const u8 state)
131{
132	return -1;
133}
134
135static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
136					       struct sock *sk, const u64 ackno)
137{
138}
139
140static inline int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
141				    const u64 *ackno, const u8 opt,
142				    const u8 *value, const u8 len)
143{
144	return -1;
145}
146
147static inline int dccp_insert_option_ackvec(const struct sock *sk,
148					    const struct sk_buff *skb)
149{
150	return -1;
151}
152
153static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
154{
155	return 0;
156}
157#endif /* CONFIG_IP_DCCP_ACKVEC */
158#endif /* _ACKVEC_H */
159