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Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -07001#ifndef _ACKVEC_H
2#define _ACKVEC_H
3/*
4 * net/dccp/ackvec.h
5 *
Gerrit Renkerf17a37c2010-11-10 21:20:07 +01006 * An implementation of Ack Vectors for the DCCP protocol
7 * Copyright (c) 2007 University of Aberdeen, Scotland, UK
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -07008 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com>
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -07009 * 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
Gerrit Renkerb20a9c22008-11-23 16:02:31 -080014#include <linux/dccp.h>
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070015#include <linux/compiler.h>
Andrea Bittau02bcf282006-03-20 17:19:55 -080016#include <linux/list.h>
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070017#include <linux/types.h>
18
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010019/*
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.
Gerrit Renkerb3d14bf2010-11-10 21:21:35 +010024 * The maximum value is bounded by the u16 types for indices and functions.
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010025 */
26#define DCCPAV_NUM_ACKVECS 2
27#define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS)
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070028
Gerrit Renker361a5c12009-02-27 22:38:28 +000029/* Estimated minimum average Ack Vector length - used for updating MPS */
30#define DCCPAV_MIN_OPTLEN 16
31
Gerrit Renker38024082010-11-14 17:25:23 +010032/* Threshold for coping with large bursts of losses */
33#define DCCPAV_BURST_THRESH (DCCPAV_MAX_ACKVEC_LEN / 8)
34
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010035enum 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
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070042
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010043static inline u8 dccp_ackvec_runlen(const u8 *cell)
44{
45 return *cell & DCCPAV_MAX_RUNLEN;
46}
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070047
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010048static inline u8 dccp_ackvec_state(const u8 *cell)
49{
50 return *cell & ~DCCPAV_MAX_RUNLEN;
51}
52
Ben Hutchings2c530402012-07-10 10:55:09 +000053/**
54 * struct dccp_ackvec - Ack Vector main data structure
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070055 *
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010056 * This implements a fixed-size circular buffer within an array and is largely
57 * based on Appendix A of RFC 4340.
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070058 *
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010059 * @av_buf: circular buffer storage area
60 * @av_buf_head: head index; begin of live portion in @av_buf
61 * @av_buf_tail: tail index; first index _after_ the live portion in @av_buf
62 * @av_buf_ackno: highest seqno of acknowledgeable packet recorded in @av_buf
Gerrit Renkerb3d14bf2010-11-10 21:21:35 +010063 * @av_tail_ackno: lowest seqno of acknowledgeable packet recorded in @av_buf
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010064 * @av_buf_nonce: ECN nonce sums, each covering subsequent segments of up to
65 * %DCCP_SINGLE_OPT_MAXLEN cells in the live portion of @av_buf
Gerrit Renkerb3d14bf2010-11-10 21:21:35 +010066 * @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010067 * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously)
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070068 */
69struct dccp_ackvec {
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010070 u8 av_buf[DCCPAV_MAX_ACKVEC_LEN];
Gerrit Renkera47c5102007-12-30 04:19:31 -080071 u16 av_buf_head;
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010072 u16 av_buf_tail;
73 u64 av_buf_ackno:48;
Gerrit Renkerb3d14bf2010-11-10 21:21:35 +010074 u64 av_tail_ackno:48;
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010075 bool av_buf_nonce[DCCPAV_NUM_ACKVECS];
Gerrit Renkerb3d14bf2010-11-10 21:21:35 +010076 u8 av_overflow:1;
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010077 struct list_head av_records;
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -070078};
79
Ben Hutchings2c530402012-07-10 10:55:09 +000080/**
81 * struct dccp_ackvec_record - Records information about sent Ack Vectors
Andrea Bittau02bcf282006-03-20 17:19:55 -080082 *
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010083 * These list entries define the additional information which the HC-Receiver
84 * keeps about recently-sent Ack Vectors; again refer to RFC 4340, Appendix A.
Andrea Bittau02bcf282006-03-20 17:19:55 -080085 *
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010086 * @avr_node: the list node in @av_records
87 * @avr_ack_seqno: sequence number of the packet the Ack Vector was sent on
88 * @avr_ack_ackno: the Ack number that this record/Ack Vector refers to
89 * @avr_ack_ptr: pointer into @av_buf where this record starts
90 * @avr_ack_runlen: run length of @avr_ack_ptr at the time of sending
91 * @avr_ack_nonce: the sum of @av_buf_nonce's at the time this record was sent
Andrea Bittau02bcf282006-03-20 17:19:55 -080092 *
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010093 * The list as a whole is sorted in descending order by @avr_ack_seqno.
Andrea Bittau02bcf282006-03-20 17:19:55 -080094 */
95struct dccp_ackvec_record {
Gerrit Renkera47c5102007-12-30 04:19:31 -080096 struct list_head avr_node;
Gerrit Renkerf17a37c2010-11-10 21:20:07 +010097 u64 avr_ack_seqno:48;
98 u64 avr_ack_ackno:48;
Gerrit Renkera47c5102007-12-30 04:19:31 -080099 u16 avr_ack_ptr;
Gerrit Renkerf17a37c2010-11-10 21:20:07 +0100100 u8 avr_ack_runlen;
101 u8 avr_ack_nonce:1;
Andrea Bittau02bcf282006-03-20 17:19:55 -0800102};
103
Arnaldo Carvalho de Melo9b07ef52006-03-20 17:16:17 -0800104extern int dccp_ackvec_init(void);
105extern void dccp_ackvec_exit(void);
106
Arnaldo Carvalho de Melo7400d782006-03-20 17:15:42 -0800107extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -0700108extern void dccp_ackvec_free(struct dccp_ackvec *av);
109
Gerrit Renker38024082010-11-14 17:25:23 +0100110extern void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb);
Gerrit Renker7d870932010-11-10 21:21:02 +0100111extern int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum);
Gerrit Renker5753fdf2010-11-14 17:25:11 +0100112extern void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno);
Gerrit Renkerb3d14bf2010-11-10 21:21:35 +0100113extern u16 dccp_ackvec_buflen(const struct dccp_ackvec *av);
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -0700114
Gerrit Renkerb3d14bf2010-11-10 21:21:35 +0100115static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av)
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -0700116{
Gerrit Renkerb3d14bf2010-11-10 21:21:35 +0100117 return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail;
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -0700118}
Gerrit Renker7e87fe82010-11-14 17:26:13 +0100119
120/**
121 * struct dccp_ackvec_parsed - Record offsets of Ack Vectors in skb
122 * @vec: start of vector (offset into skb)
123 * @len: length of @vec
124 * @nonce: whether @vec had an ECN nonce of 0 or 1
125 * @node: FIFO - arranged in descending order of ack_ackno
Ben Hutchings2c530402012-07-10 10:55:09 +0000126 *
Gerrit Renker7e87fe82010-11-14 17:26:13 +0100127 * This structure is used by CCIDs to access Ack Vectors in a received skb.
128 */
129struct dccp_ackvec_parsed {
130 u8 *vec,
131 len,
132 nonce:1;
133 struct list_head node;
134};
135
136extern int dccp_ackvec_parsed_add(struct list_head *head,
137 u8 *vec, u8 len, u8 nonce);
138extern void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks);
Arnaldo Carvalho de Meloae31c332005-09-18 00:17:51 -0700139#endif /* _ACKVEC_H */