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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 | ||
38024086 GR |
32 | /* Threshold for coping with large bursts of losses */ |
33 | #define DCCPAV_BURST_THRESH (DCCPAV_MAX_ACKVEC_LEN / 8) | |
34 | ||
f17a37c9 GR |
35 | enum dccp_ackvec_states { |
36 | DCCPAV_RECEIVED = 0x00, | |
37 | DCCPAV_ECN_MARKED = 0x40, | |
38 | DCCPAV_RESERVED = 0x80, | |
39 | DCCPAV_NOT_RECEIVED = 0xC0 | |
40 | }; | |
41 | #define DCCPAV_MAX_RUNLEN 0x3F | |
ae31c339 | 42 | |
f17a37c9 GR |
43 | static inline u8 dccp_ackvec_runlen(const u8 *cell) |
44 | { | |
45 | return *cell & DCCPAV_MAX_RUNLEN; | |
46 | } | |
ae31c339 | 47 | |
f17a37c9 GR |
48 | static inline u8 dccp_ackvec_state(const u8 *cell) |
49 | { | |
50 | return *cell & ~DCCPAV_MAX_RUNLEN; | |
51 | } | |
52 | ||
53 | /** struct dccp_ackvec - Ack Vector main data structure | |
ae31c339 | 54 | * |
f17a37c9 GR |
55 | * This implements a fixed-size circular buffer within an array and is largely |
56 | * based on Appendix A of RFC 4340. | |
ae31c339 | 57 | * |
f17a37c9 GR |
58 | * @av_buf: circular buffer storage area |
59 | * @av_buf_head: head index; begin of live portion in @av_buf | |
60 | * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf | |
61 | * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf | |
b3d14bff | 62 | * @av_tail_ackno: lowest seqno of acknowledgeable packet recorded in @av_buf |
f17a37c9 GR |
63 | * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to |
64 | * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf | |
b3d14bff | 65 | * @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound |
f17a37c9 | 66 | * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously) |
ae31c339 ACM |
67 | */ |
68 | struct dccp_ackvec { | |
f17a37c9 | 69 | u8 av_buf[DCCPAV_MAX_ACKVEC_LEN]; |
a47c5104 | 70 | u16 av_buf_head; |
f17a37c9 GR |
71 | u16 av_buf_tail; |
72 | u64 av_buf_ackno:48; | |
b3d14bff | 73 | u64 av_tail_ackno:48; |
f17a37c9 | 74 | bool av_buf_nonce[DCCPAV_NUM_ACKVECS]; |
b3d14bff | 75 | u8 av_overflow:1; |
f17a37c9 | 76 | struct list_head av_records; |
ae31c339 ACM |
77 | }; |
78 | ||
f17a37c9 | 79 | /** struct dccp_ackvec_record - Records information about sent Ack Vectors |
02bcf28c | 80 | * |
f17a37c9 GR |
81 | * These list entries define the additional information which the HC-Receiver |
82 | * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A. | |
02bcf28c | 83 | * |
f17a37c9 GR |
84 | * @avr_node: the list node in @av_records |
85 | * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on | |
86 | * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to | |
87 | * @avr_ack_ptr: pointer into @av_buf where this record starts | |
88 | * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending | |
89 | * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent | |
02bcf28c | 90 | * |
f17a37c9 | 91 | * The list as a whole is sorted in descending order by @avr_ack_seqno. |
02bcf28c AB |
92 | */ |
93 | struct dccp_ackvec_record { | |
a47c5104 | 94 | struct list_head avr_node; |
f17a37c9 GR |
95 | u64 avr_ack_seqno:48; |
96 | u64 avr_ack_ackno:48; | |
a47c5104 | 97 | u16 avr_ack_ptr; |
f17a37c9 GR |
98 | u8 avr_ack_runlen; |
99 | u8 avr_ack_nonce:1; | |
02bcf28c AB |
100 | }; |
101 | ||
9b07ef5d ACM |
102 | extern int dccp_ackvec_init(void); |
103 | extern void dccp_ackvec_exit(void); | |
104 | ||
7400d781 | 105 | extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); |
ae31c339 ACM |
106 | extern void dccp_ackvec_free(struct dccp_ackvec *av); |
107 | ||
38024086 | 108 | extern void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb); |
7d870936 | 109 | extern int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum); |
5753fdfe | 110 | extern void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno); |
b3d14bff | 111 | extern u16 dccp_ackvec_buflen(const struct dccp_ackvec *av); |
ae31c339 | 112 | |
b3d14bff | 113 | static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av) |
ae31c339 | 114 | { |
b3d14bff | 115 | return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail; |
ae31c339 | 116 | } |
7e87fe84 GR |
117 | |
118 | /** | |
119 | * struct dccp_ackvec_parsed - Record offsets of Ack Vectors in skb | |
120 | * @vec: start of vector (offset into skb) | |
121 | * @len: length of @vec | |
122 | * @nonce: whether @vec had an ECN nonce of 0 or 1 | |
123 | * @node: FIFO - arranged in descending order of ack_ackno | |
124 | * This structure is used by CCIDs to access Ack Vectors in a received skb. | |
125 | */ | |
126 | struct dccp_ackvec_parsed { | |
127 | u8 *vec, | |
128 | len, | |
129 | nonce:1; | |
130 | struct list_head node; | |
131 | }; | |
132 | ||
133 | extern int dccp_ackvec_parsed_add(struct list_head *head, | |
134 | u8 *vec, u8 len, u8 nonce); | |
135 | extern void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks); | |
ae31c339 | 136 | #endif /* _ACKVEC_H */ |