xref: /openbmc/linux/net/dccp/ackvec.h (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
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  */
56 struct 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 
72 struct sock;
73 struct sk_buff;
74 
75 #ifdef CONFIG_IP_DCCP_ACKVEC
76 extern struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len,
77 					  const gfp_t priority);
78 extern void dccp_ackvec_free(struct dccp_ackvec *av);
79 
80 extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk,
81 			   const u64 ackno, const u8 state);
82 
83 extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
84 					struct sock *sk, const u64 ackno);
85 extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
86 			     const u8 opt, const u8 *value, const u8 len);
87 
88 extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb);
89 
90 static 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 */
95 static inline struct dccp_ackvec *dccp_ackvec_alloc(unsigned int len,
96 					   const gfp_t priority)
97 {
98 	return NULL;
99 }
100 
101 static inline void dccp_ackvec_free(struct dccp_ackvec *av)
102 {
103 }
104 
105 static 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 
111 static inline void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av,
112 					       struct sock *sk, const u64 ackno)
113 {
114 }
115 
116 static 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 
122 static inline int dccp_insert_option_ackvec(const struct sock *sk,
123 					    const struct sk_buff *skb)
124 {
125 	return -1;
126 }
127 
128 static 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 */
134