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-rw-r--r--net/dccp/ackvec.h151
1 files changed, 88 insertions, 63 deletions
diff --git a/net/dccp/ackvec.h b/net/dccp/ackvec.h
index 7ea557b7c6b1..e2ab0627a5ff 100644
--- a/net/dccp/ackvec.h
+++ b/net/dccp/ackvec.h
@@ -3,9 +3,9 @@
3/* 3/*
4 * net/dccp/ackvec.h 4 * net/dccp/ackvec.h
5 * 5 *
6 * An implementation of the DCCP protocol 6 * An implementation of Ack Vectors for the DCCP protocol
7 * Copyright (c) 2007 University of Aberdeen, Scotland, UK
7 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@mandriva.com> 8 * 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 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 10 * under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation. 11 * published by the Free Software Foundation.
@@ -13,99 +13,124 @@
13 13
14#include <linux/dccp.h> 14#include <linux/dccp.h>
15#include <linux/compiler.h> 15#include <linux/compiler.h>
16#include <linux/ktime.h>
17#include <linux/list.h> 16#include <linux/list.h>
18#include <linux/types.h> 17#include <linux/types.h>
19 18
20/* We can spread an ack vector across multiple options */ 19/*
21#define DCCP_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * 2) 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 * The maximum value is bounded by the u16 types for indices and functions.
25 */
26#define DCCPAV_NUM_ACKVECS 2
27#define DCCPAV_MAX_ACKVEC_LEN (DCCP_SINGLE_OPT_MAXLEN * DCCPAV_NUM_ACKVECS)
22 28
23/* Estimated minimum average Ack Vector length - used for updating MPS */ 29/* Estimated minimum average Ack Vector length - used for updating MPS */
24#define DCCPAV_MIN_OPTLEN 16 30#define DCCPAV_MIN_OPTLEN 16
25 31
26#define DCCP_ACKVEC_STATE_RECEIVED 0 32/* Threshold for coping with large bursts of losses */
27#define DCCP_ACKVEC_STATE_ECN_MARKED (1 << 6) 33#define DCCPAV_BURST_THRESH (DCCPAV_MAX_ACKVEC_LEN / 8)
28#define DCCP_ACKVEC_STATE_NOT_RECEIVED (3 << 6)
29 34
30#define DCCP_ACKVEC_STATE_MASK 0xC0 /* 11000000 */ 35enum dccp_ackvec_states {
31#define DCCP_ACKVEC_LEN_MASK 0x3F /* 00111111 */ 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
32 42
33/** struct dccp_ackvec - ack vector 43static inline u8 dccp_ackvec_runlen(const u8 *cell)
34 * 44{
35 * This data structure is the one defined in RFC 4340, Appendix A. 45 return *cell & DCCPAV_MAX_RUNLEN;
36 * 46}
37 * @av_buf_head - circular buffer head 47
38 * @av_buf_tail - circular buffer tail 48static inline u8 dccp_ackvec_state(const u8 *cell)
39 * @av_buf_ackno - ack # of the most recent packet acknowledgeable in the 49{
40 * buffer (i.e. %av_buf_head) 50 return *cell & ~DCCPAV_MAX_RUNLEN;
41 * @av_buf_nonce - the one-bit sum of the ECN Nonces on all packets acked 51}
42 * by the buffer with State 0 52
43 * 53/** struct dccp_ackvec - Ack Vector main data structure
44 * Additionally, the HC-Receiver must keep some information about the
45 * Ack Vectors it has recently sent. For each packet sent carrying an
46 * Ack Vector, it remembers four variables:
47 * 54 *
48 * @av_records - list of dccp_ackvec_record 55 * This implements a fixed-size circular buffer within an array and is largely
49 * @av_ack_nonce - the one-bit sum of the ECN Nonces for all State 0. 56 * based on Appendix A of RFC 4340.
50 * 57 *
51 * @av_time - the time in usecs 58 * @av_buf: circular buffer storage area
52 * @av_buf - circular buffer of acknowledgeable packets 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
62 * @av_tail_ackno: lowest seqno of acknowledgeable packet recorded in @av_buf
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
65 * @av_overflow: if 1 then buf_head == buf_tail indicates buffer wraparound
66 * @av_records: list of %dccp_ackvec_record (Ack Vectors sent previously)
53 */ 67 */
54struct dccp_ackvec { 68struct dccp_ackvec {
55 u64 av_buf_ackno; 69 u8 av_buf[DCCPAV_MAX_ACKVEC_LEN];
56 struct list_head av_records;
57 ktime_t av_time;
58 u16 av_buf_head; 70 u16 av_buf_head;
59 u16 av_vec_len; 71 u16 av_buf_tail;
60 u8 av_buf_nonce; 72 u64 av_buf_ackno:48;
61 u8 av_ack_nonce; 73 u64 av_tail_ackno:48;
62 u8 av_buf[DCCP_MAX_ACKVEC_LEN]; 74 bool av_buf_nonce[DCCPAV_NUM_ACKVECS];
75 u8 av_overflow:1;
76 struct list_head av_records;
63}; 77};
64 78
65/** struct dccp_ackvec_record - ack vector record 79/** struct dccp_ackvec_record - Records information about sent Ack Vectors
66 * 80 *
67 * ACK vector record as defined in Appendix A of spec. 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.
68 * 83 *
69 * The list is sorted by avr_ack_seqno 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
70 * 90 *
71 * @avr_node - node in av_records 91 * The list as a whole is sorted in descending order by @avr_ack_seqno.
72 * @avr_ack_seqno - sequence number of the packet this record was sent on
73 * @avr_ack_ackno - sequence number being acknowledged
74 * @avr_ack_ptr - pointer into av_buf where this record starts
75 * @avr_ack_nonce - av_ack_nonce at the time this record was sent
76 * @avr_sent_len - lenght of the record in av_buf
77 */ 92 */
78struct dccp_ackvec_record { 93struct dccp_ackvec_record {
79 struct list_head avr_node; 94 struct list_head avr_node;
80 u64 avr_ack_seqno; 95 u64 avr_ack_seqno:48;
81 u64 avr_ack_ackno; 96 u64 avr_ack_ackno:48;
82 u16 avr_ack_ptr; 97 u16 avr_ack_ptr;
83 u16 avr_sent_len; 98 u8 avr_ack_runlen;
84 u8 avr_ack_nonce; 99 u8 avr_ack_nonce:1;
85}; 100};
86 101
87struct sock;
88struct sk_buff;
89
90extern int dccp_ackvec_init(void); 102extern int dccp_ackvec_init(void);
91extern void dccp_ackvec_exit(void); 103extern void dccp_ackvec_exit(void);
92 104
93extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority); 105extern struct dccp_ackvec *dccp_ackvec_alloc(const gfp_t priority);
94extern void dccp_ackvec_free(struct dccp_ackvec *av); 106extern void dccp_ackvec_free(struct dccp_ackvec *av);
95 107
96extern int dccp_ackvec_add(struct dccp_ackvec *av, const struct sock *sk, 108extern void dccp_ackvec_input(struct dccp_ackvec *av, struct sk_buff *skb);
97 const u64 ackno, const u8 state); 109extern int dccp_ackvec_update_records(struct dccp_ackvec *av, u64 seq, u8 sum);
98 110extern void dccp_ackvec_clear_state(struct dccp_ackvec *av, const u64 ackno);
99extern void dccp_ackvec_check_rcv_ackno(struct dccp_ackvec *av, 111extern u16 dccp_ackvec_buflen(const struct dccp_ackvec *av);
100 struct sock *sk, const u64 ackno);
101extern int dccp_ackvec_parse(struct sock *sk, const struct sk_buff *skb,
102 u64 *ackno, const u8 opt,
103 const u8 *value, const u8 len);
104 112
105extern int dccp_insert_option_ackvec(struct sock *sk, struct sk_buff *skb); 113static inline bool dccp_ackvec_is_empty(const struct dccp_ackvec *av)
106
107static inline int dccp_ackvec_pending(const struct dccp_ackvec *av)
108{ 114{
109 return av->av_vec_len; 115 return av->av_overflow == 0 && av->av_buf_head == av->av_buf_tail;
110} 116}
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 */
126struct dccp_ackvec_parsed {
127 u8 *vec,
128 len,
129 nonce:1;
130 struct list_head node;
131};
132
133extern int dccp_ackvec_parsed_add(struct list_head *head,
134 u8 *vec, u8 len, u8 nonce);
135extern void dccp_ackvec_parsed_cleanup(struct list_head *parsed_chunks);
111#endif /* _ACKVEC_H */ 136#endif /* _ACKVEC_H */
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