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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. | |
b3d14bff | 24 | * The maximum value is bounded by the u16 types for indices and functions. |
f17a37c9 GR |
25 | */ |
26 | #define DCCPAV_NUM_ACKVECS 2 | |
27 | #define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS) | |
ae31c339 | 28 | |
361a5c1d GR |
29 | /* Estimated minimum average Ack Vector length - used for updating MPS */ |
30 | #define DCCPAV_MIN_OPTLEN 16 | |
31 | ||
f17a37c9 GR |
32 | enum dccp_ackvec_states { |
33 | DCCPAV_RECEIVED = 0x00, | |
34 | DCCPAV_ECN_MARKED = 0x40, | |
35 | DCCPAV_RESERVED = 0x80, | |
36 | DCCPAV_NOT_RECEIVED = 0xC0 | |
37 | }; | |
38 | #define DCCPAV_MAX_RUNLEN 0x3F | |
ae31c339 | 39 | |
f17a37c9 GR |
40 | static inline u8 dccp_ackvec_runlen(const u8 *cell) |
41 | { | |
42 | return *cell & DCCPAV_MAX_RUNLEN; | |
43 | } | |
ae31c339 | 44 | |
f17a37c9 GR |
45 | static inline u8 dccp_ackvec_state(const u8 *cell) |
46 | { | |
47 | return *cell & ~DCCPAV_MAX_RUNLEN; | |
48 | } | |
49 | ||
50 | /** struct dccp_ackvec - Ack Vector main data structure | |
ae31c339 | 51 | * |
f17a37c9 GR |
52 | * This implements a fixed-size circular buffer within an array and is largely |
53 | * based on Appendix A of RFC 4340. | |
ae31c339 | 54 | * |
f17a37c9 GR |
55 | * @av_buf: circular buffer storage area |
56 | * @av_buf_head: head index; begin of live portion in @av_buf | |
57 | * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf | |
58 | * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf | |
b3d14bff | 59 | * @av_tail_ackno: lowest seqno of acknowledgeable packet recorded in @av_buf |
f17a37c9 GR |
60 | * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to |
61 | * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf | |
b3d14bff | 62 | * @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound |
f17a37c9 GR |
63 | * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously) |
64 | * @av_veclen: length of the live portion of @av_buf | |
ae31c339 ACM |
65 | */ |
66 | struct dccp_ackvec { | |
f17a37c9 | 67 | u8 av_buf[DCCPAV_MAX_ACKVEC_LEN]; |
a47c5104 | 68 | u16 av_buf_head; |
f17a37c9 GR |
69 | u16 av_buf_tail; |
70 | u64 av_buf_ackno:48; | |
b3d14bff | 71 | u64 av_tail_ackno:48; |
f17a37c9 | 72 | bool av_buf_nonce[DCCPAV_NUM_ACKVECS]; |
b3d14bff | 73 | u8 av_overflow:1; |
f17a37c9 | 74 | struct list_head av_records; |
a47c5104 | 75 | u16 av_vec_len; |
ae31c339 ACM |
76 | }; |
77 | ||
f17a37c9 | 78 | /** struct dccp_ackvec_record - Records information about sent Ack Vectors |
02bcf28c | 79 | * |
f17a37c9 GR |
80 | * These list entries define the additional information which the HC-Receiver |
81 | * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A. | |
02bcf28c | 82 | * |
f17a37c9 GR |
83 | * @avr_node: the list node in @av_records |
84 | * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on | |
85 | * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to | |
86 | * @avr_ack_ptr: pointer into @av_buf where this record starts | |
87 | * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending | |
88 | * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent | |
02bcf28c | 89 | * |
f17a37c9 | 90 | * The list as a whole is sorted in descending order by @avr_ack_seqno. |
02bcf28c AB |
91 | */ |
92 | struct dccp_ackvec_record { | |
a47c5104 | 93 | struct list_head avr_node; |
f17a37c9 GR |
94 | u64 avr_ack_seqno:48; |
95 | u64 avr_ack_ackno:48; | |
a47c5104 | 96 | u16 avr_ack_ptr; |
f17a37c9 GR |
97 | u8 avr_ack_runlen; |
98 | u8 avr_ack_nonce:1; | |
02bcf28c AB |
99 | }; |
100 | ||
ae31c339 ACM |
101 | struct sock; |
102 | struct sk_buff; | |
103 | ||
9b07ef5d ACM |
104 | extern int dccp_ackvec_init(void); |
105 | extern void dccp_ackvec_exit(void); | |
106 | ||
7400d781 | 107 | extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); |
ae31c339 ACM |
108 | extern void dccp_ackvec_free(struct dccp_ackvec *av); |
109 | ||
110 | extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, | |
111 | const u64 ackno, const u8 state); | |
112 | ||
113 | extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, | |
114 | struct sock *sk, const u64 ackno); | |
115 | extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb, | |
bdf13d20 AB |
116 | u64 *ackno, const u8 opt, |
117 | const u8 *value, const u8 len); | |
ae31c339 | 118 | |
7d870936 | 119 | extern int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum); |
5753fdfe | 120 | extern void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno); |
b3d14bff | 121 | extern u16 dccp_ackvec_buflen(const struct dccp_ackvec *av); |
ae31c339 | 122 | |
b3d14bff | 123 | static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av) |
ae31c339 | 124 | { |
b3d14bff | 125 | return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail; |
ae31c339 | 126 | } |
ae31c339 | 127 | #endif /* _ACKVEC_H */ |