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8c60f3fa | 1 | /* |
276f2edc | 2 | * Packet RX/TX history data structures and routines for TFRC-based protocols. |
8c60f3fa | 3 | * |
276f2edc | 4 | * Copyright (c) 2007 The University of Aberdeen, Scotland, UK |
e6bccd35 | 5 | * Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand. |
8c60f3fa | 6 | * |
8c60f3fa ACM |
7 | * This code has been developed by the University of Waikato WAND |
8 | * research group. For further information please see http://www.wand.net.nz/ | |
e6bccd35 | 9 | * or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz |
8c60f3fa ACM |
10 | * |
11 | * This code also uses code from Lulea University, rereleased as GPL by its | |
12 | * authors: | |
13 | * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon | |
14 | * | |
15 | * Changes to meet Linux coding standards, to make it meet latest ccid3 draft | |
16 | * and to make it work as a loadable module in the DCCP stack written by | |
17 | * Arnaldo Carvalho de Melo <acme@conectiva.com.br>. | |
18 | * | |
19 | * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br> | |
20 | * | |
21 | * This program is free software; you can redistribute it and/or modify | |
22 | * it under the terms of the GNU General Public License as published by | |
23 | * the Free Software Foundation; either version 2 of the License, or | |
24 | * (at your option) any later version. | |
25 | * | |
26 | * This program is distributed in the hope that it will be useful, | |
27 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
28 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
29 | * GNU General Public License for more details. | |
30 | * | |
31 | * You should have received a copy of the GNU General Public License | |
32 | * along with this program; if not, write to the Free Software | |
33 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
34 | */ | |
35 | ||
36 | #ifndef _DCCP_PKT_HIST_ | |
37 | #define _DCCP_PKT_HIST_ | |
38 | ||
8a9c7e92 GR |
39 | #include <linux/list.h> |
40 | #include <linux/slab.h> | |
41 | #include "tfrc.h" | |
072ab6c6 | 42 | |
d2c72630 GR |
43 | /** |
44 | * tfrc_tx_hist_entry - Simple singly-linked TX history list | |
45 | * @next: next oldest entry (LIFO order) | |
46 | * @seqno: sequence number of this entry | |
47 | * @stamp: send time of packet with sequence number @seqno | |
48 | */ | |
49 | struct tfrc_tx_hist_entry { | |
50 | struct tfrc_tx_hist_entry *next; | |
51 | u64 seqno; | |
52 | ktime_t stamp; | |
53 | }; | |
54 | ||
55 | static inline struct tfrc_tx_hist_entry * | |
56 | tfrc_tx_hist_find_entry(struct tfrc_tx_hist_entry *head, u64 seqno) | |
57 | { | |
58 | while (head != NULL && head->seqno != seqno) | |
59 | head = head->next; | |
60 | return head; | |
61 | } | |
8c60f3fa | 62 | |
276f2edc ACM |
63 | extern int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno); |
64 | extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp); | |
8c60f3fa | 65 | |
b84a2189 ACM |
66 | /* Subtraction a-b modulo-16, respects circular wrap-around */ |
67 | #define SUB16(a, b) (((a) + 16 - (b)) & 0xF) | |
68 | ||
69 | /* Number of packets to wait after a missing packet (RFC 4342, 6.1) */ | |
70 | #define TFRC_NDUPACK 3 | |
71 | ||
72 | /** | |
73 | * tfrc_rx_hist_entry - Store information about a single received packet | |
74 | * @tfrchrx_seqno: DCCP packet sequence number | |
75 | * @tfrchrx_ccval: window counter value of packet (RFC 4342, 8.1) | |
76 | * @tfrchrx_ndp: the NDP count (if any) of the packet | |
77 | * @tfrchrx_tstamp: actual receive time of packet | |
85dcb1f7 | 78 | */ |
d58d1af0 | 79 | struct tfrc_rx_hist_entry { |
d58d1af0 ACM |
80 | u64 tfrchrx_seqno:48, |
81 | tfrchrx_ccval:4, | |
82 | tfrchrx_type:4; | |
5b5d0e70 | 83 | u64 tfrchrx_ndp:48; |
d58d1af0 | 84 | ktime_t tfrchrx_tstamp; |
85dcb1f7 | 85 | }; |
8c60f3fa | 86 | |
b84a2189 ACM |
87 | /** |
88 | * tfrc_rx_hist - RX history structure for TFRC-based protocols | |
b84a2189 ACM |
89 | * @ring: Packet history for RTT sampling and loss detection |
90 | * @loss_count: Number of entries in circular history | |
91 | * @loss_start: Movable index (for loss detection) | |
92 | * @rtt_sample_prev: Used during RTT sampling, points to candidate entry | |
93 | */ | |
94 | struct tfrc_rx_hist { | |
95 | struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1]; | |
96 | u8 loss_count:2, | |
97 | loss_start:2; | |
98 | #define rtt_sample_prev loss_start | |
99 | }; | |
85dcb1f7 | 100 | |
8995a238 GR |
101 | /** |
102 | * tfrc_rx_hist_index - index to reach n-th entry after loss_start | |
103 | */ | |
104 | static inline u8 tfrc_rx_hist_index(const struct tfrc_rx_hist *h, const u8 n) | |
105 | { | |
106 | return (h->loss_start + n) & TFRC_NDUPACK; | |
107 | } | |
108 | ||
109 | /** | |
110 | * tfrc_rx_hist_last_rcv - entry with highest-received-seqno so far | |
111 | */ | |
112 | static inline struct tfrc_rx_hist_entry * | |
113 | tfrc_rx_hist_last_rcv(const struct tfrc_rx_hist *h) | |
114 | { | |
115 | return h->ring[tfrc_rx_hist_index(h, h->loss_count)]; | |
116 | } | |
117 | ||
118 | /** | |
119 | * tfrc_rx_hist_entry - return the n-th history entry after loss_start | |
120 | */ | |
121 | static inline struct tfrc_rx_hist_entry * | |
122 | tfrc_rx_hist_entry(const struct tfrc_rx_hist *h, const u8 n) | |
123 | { | |
124 | return h->ring[tfrc_rx_hist_index(h, n)]; | |
125 | } | |
126 | ||
127 | /** | |
128 | * tfrc_rx_hist_loss_prev - entry with highest-received-seqno before loss was detected | |
129 | */ | |
130 | static inline struct tfrc_rx_hist_entry * | |
131 | tfrc_rx_hist_loss_prev(const struct tfrc_rx_hist *h) | |
132 | { | |
133 | return h->ring[h->loss_start]; | |
134 | } | |
135 | ||
de0d411c | 136 | /* indicate whether previously a packet was detected missing */ |
b552c623 | 137 | static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h) |
de0d411c | 138 | { |
b552c623 | 139 | return h->loss_count > 0; |
de0d411c GR |
140 | } |
141 | ||
b84a2189 | 142 | extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, |
5b5d0e70 | 143 | const struct sk_buff *skb, const u64 ndp); |
8c60f3fa | 144 | |
b84a2189 | 145 | extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb); |
de0d411c | 146 | |
8a9c7e92 | 147 | struct tfrc_loss_hist; |
de0d411c GR |
148 | extern int tfrc_rx_handle_loss(struct tfrc_rx_hist *h, |
149 | struct tfrc_loss_hist *lh, | |
5b5d0e70 | 150 | struct sk_buff *skb, const u64 ndp, |
de0d411c GR |
151 | u32 (*first_li)(struct sock *sk), |
152 | struct sock *sk); | |
b84a2189 ACM |
153 | extern u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, |
154 | const struct sk_buff *skb); | |
155 | extern int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h); | |
156 | extern void tfrc_rx_hist_purge(struct tfrc_rx_hist *h); | |
29e4f8b3 | 157 | |
8c60f3fa | 158 | #endif /* _DCCP_PKT_HIST_ */ |