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ae31c339 ACM |
1 | #ifndef _ACKVEC_H |
2 | #define _ACKVEC_H | |
3 | /* | |
4 | * net/dccp/ackvec.h | |
5 | * | |
f17a37c9 GR |
6 | * An implementation of Ack Vectors for the DCCP protocol |
7 | * Copyright (c) 2007 University of Aberdeen, Scotland, UK | |
ae31c339 | 8 | * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com> |
ae31c339 ACM |
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 | ||
b20a9c24 | 14 | #include <linux/dccp.h> |
ae31c339 | 15 | #include <linux/compiler.h> |
02bcf28c | 16 | #include <linux/list.h> |
ae31c339 ACM |
17 | #include <linux/types.h> |
18 | ||
f17a37c9 GR |
19 | /* |
20 | * Ack Vector buffer space is static, in multiples of %DCCP_SINGLE_OPT_MAXLEN, | |
21 | * the maximum size of a single Ack Vector. Setting %DCCPAV_NUM_ACKVECS to 1 | |
22 | * will be sufficient for most cases of low Ack Ratios, using a value of 2 gives | |
23 | * more headroom if Ack Ratio is higher or when the sender acknowledges slowly. | |
24 | */ | |
25 | #define DCCPAV_NUM_ACKVECS 2 | |
26 | #define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS) | |
ae31c339 | 27 | |
361a5c1d GR |
28 | /* Estimated minimum average Ack Vector length - used for updating MPS */ |
29 | #define DCCPAV_MIN_OPTLEN 16 | |
30 | ||
f17a37c9 GR |
31 | enum dccp_ackvec_states { |
32 | DCCPAV_RECEIVED = 0x00, | |
33 | DCCPAV_ECN_MARKED = 0x40, | |
34 | DCCPAV_RESERVED = 0x80, | |
35 | DCCPAV_NOT_RECEIVED = 0xC0 | |
36 | }; | |
37 | #define DCCPAV_MAX_RUNLEN 0x3F | |
ae31c339 | 38 | |
f17a37c9 GR |
39 | static inline u8 dccp_ackvec_runlen(const u8 *cell) |
40 | { | |
41 | return *cell & DCCPAV_MAX_RUNLEN; | |
42 | } | |
ae31c339 | 43 | |
f17a37c9 GR |
44 | static inline u8 dccp_ackvec_state(const u8 *cell) |
45 | { | |
46 | return *cell & ~DCCPAV_MAX_RUNLEN; | |
47 | } | |
48 | ||
49 | /** struct dccp_ackvec - Ack Vector main data structure | |
ae31c339 | 50 | * |
f17a37c9 GR |
51 | * This implements a fixed-size circular buffer within an array and is largely |
52 | * based on Appendix A of RFC 4340. | |
ae31c339 | 53 | * |
f17a37c9 GR |
54 | * @av_buf: circular buffer storage area |
55 | * @av_buf_head: head index; begin of live portion in @av_buf | |
56 | * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf | |
57 | * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf | |
58 | * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to | |
59 | * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf | |
60 | * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously) | |
61 | * @av_veclen: length of the live portion of @av_buf | |
ae31c339 ACM |
62 | */ |
63 | struct dccp_ackvec { | |
f17a37c9 | 64 | u8 av_buf[DCCPAV_MAX_ACKVEC_LEN]; |
a47c5104 | 65 | u16 av_buf_head; |
f17a37c9 GR |
66 | u16 av_buf_tail; |
67 | u64 av_buf_ackno:48; | |
68 | bool av_buf_nonce[DCCPAV_NUM_ACKVECS]; | |
69 | struct list_head av_records; | |
a47c5104 | 70 | u16 av_vec_len; |
ae31c339 ACM |
71 | }; |
72 | ||
f17a37c9 | 73 | /** struct dccp_ackvec_record - Records information about sent Ack Vectors |
02bcf28c | 74 | * |
f17a37c9 GR |
75 | * These list entries define the additional information which the HC-Receiver |
76 | * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A. | |
02bcf28c | 77 | * |
f17a37c9 GR |
78 | * @avr_node: the list node in @av_records |
79 | * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on | |
80 | * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to | |
81 | * @avr_ack_ptr: pointer into @av_buf where this record starts | |
82 | * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending | |
83 | * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent | |
02bcf28c | 84 | * |
f17a37c9 | 85 | * The list as a whole is sorted in descending order by @avr_ack_seqno. |
02bcf28c AB |
86 | */ |
87 | struct dccp_ackvec_record { | |
a47c5104 | 88 | struct list_head avr_node; |
f17a37c9 GR |
89 | u64 avr_ack_seqno:48; |
90 | u64 avr_ack_ackno:48; | |
a47c5104 | 91 | u16 avr_ack_ptr; |
f17a37c9 GR |
92 | u8 avr_ack_runlen; |
93 | u8 avr_ack_nonce:1; | |
02bcf28c AB |
94 | }; |
95 | ||
ae31c339 ACM |
96 | struct sock; |
97 | struct sk_buff; | |
98 | ||
9b07ef5d ACM |
99 | extern int dccp_ackvec_init(void); |
100 | extern void dccp_ackvec_exit(void); | |
101 | ||
7400d781 | 102 | extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); |
ae31c339 ACM |
103 | extern void dccp_ackvec_free(struct dccp_ackvec *av); |
104 | ||
105 | extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, | |
106 | const u64 ackno, const u8 state); | |
107 | ||
108 | extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, | |
109 | struct sock *sk, const u64 ackno); | |
110 | extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, | |
bdf13d20 AB |
111 | u64 *ackno, const u8 opt, |
112 | const u8 *value, const u8 len); | |
ae31c339 ACM |
113 | |
114 | extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb); | |
115 | ||
116 | static inline int dccp_ackvec_pending(const struct dccp_ackvec *av) | |
117 | { | |
a47c5104 | 118 | return av->av_vec_len; |
ae31c339 | 119 | } |
ae31c339 | 120 | #endif /* _ACKVEC_H */ |