packet_history.h revision 88e97a93342c0b9e835d510921e7b2df8547d1bd
1/* 2 * Packet RX/TX history data structures and routines for TFRC-based protocols. 3 * 4 * Copyright (c) 2007 The University of Aberdeen, Scotland, UK 5 * Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand. 6 * 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/ 9 * or e-mail Ian McDonald - ian.mcdonald@jandi.co.nz 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 39#include <linux/list.h> 40#include <linux/slab.h> 41#include "tfrc.h" 42 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 */ 49struct tfrc_tx_hist_entry { 50 struct tfrc_tx_hist_entry *next; 51 u64 seqno; 52 ktime_t stamp; 53}; 54 55static 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} 62 63extern int tfrc_tx_hist_add(struct tfrc_tx_hist_entry **headp, u64 seqno); 64extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp); 65 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 78 */ 79struct tfrc_rx_hist_entry { 80 u64 tfrchrx_seqno:48, 81 tfrchrx_ccval:4, 82 tfrchrx_type:4; 83 u64 tfrchrx_ndp:48; 84 ktime_t tfrchrx_tstamp; 85}; 86 87/** 88 * tfrc_rx_hist - RX history structure for TFRC-based protocols 89 * 90 * @ring: Packet history for RTT sampling and loss detection 91 * @loss_count: Number of entries in circular history 92 * @loss_start: Movable index (for loss detection) 93 * @rtt_sample_prev: Used during RTT sampling, points to candidate entry 94 * @rtt_estimate: Receiver RTT estimate 95 * @packet_size: Packet size in bytes (as per RFC 3448, 3.1) 96 * @bytes_recvd: Number of bytes received since @bytes_start 97 * @bytes_start: Start time for counting @bytes_recvd 98 */ 99struct tfrc_rx_hist { 100 struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1]; 101 u8 loss_count:2, 102 loss_start:2; 103 /* Receiver RTT sampling */ 104#define rtt_sample_prev loss_start 105 u32 rtt_estimate; 106 /* Receiver sampling of application payload lengths */ 107 u32 packet_size, 108 bytes_recvd; 109 ktime_t bytes_start; 110}; 111 112/** 113 * tfrc_rx_hist_index - index to reach n-th entry after loss_start 114 */ 115static inline u8 tfrc_rx_hist_index(const struct tfrc_rx_hist *h, const u8 n) 116{ 117 return (h->loss_start + n) & TFRC_NDUPACK; 118} 119 120/** 121 * tfrc_rx_hist_last_rcv - entry with highest-received-seqno so far 122 */ 123static inline struct tfrc_rx_hist_entry * 124 tfrc_rx_hist_last_rcv(const struct tfrc_rx_hist *h) 125{ 126 return h->ring[tfrc_rx_hist_index(h, h->loss_count)]; 127} 128 129/** 130 * tfrc_rx_hist_entry - return the n-th history entry after loss_start 131 */ 132static inline struct tfrc_rx_hist_entry * 133 tfrc_rx_hist_entry(const struct tfrc_rx_hist *h, const u8 n) 134{ 135 return h->ring[tfrc_rx_hist_index(h, n)]; 136} 137 138/** 139 * tfrc_rx_hist_loss_prev - entry with highest-received-seqno before loss was detected 140 */ 141static inline struct tfrc_rx_hist_entry * 142 tfrc_rx_hist_loss_prev(const struct tfrc_rx_hist *h) 143{ 144 return h->ring[h->loss_start]; 145} 146 147/* indicate whether previously a packet was detected missing */ 148static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h) 149{ 150 return h->loss_count > 0; 151} 152 153/* 154 * Accessor functions to retrieve parameters sampled by the RX history 155 */ 156static inline u32 tfrc_rx_hist_packet_size(const struct tfrc_rx_hist *h) 157{ 158 if (h->packet_size == 0) { 159 DCCP_WARN("No sample for s, using fallback\n"); 160 return TCP_MIN_RCVMSS; 161 } 162 return h->packet_size; 163 164} 165static inline u32 tfrc_rx_hist_rtt(const struct tfrc_rx_hist *h) 166{ 167 if (h->rtt_estimate == 0) { 168 DCCP_WARN("No RTT estimate available, using fallback RTT\n"); 169 return DCCP_FALLBACK_RTT; 170 } 171 return h->rtt_estimate; 172} 173 174static inline void tfrc_rx_hist_restart_byte_counter(struct tfrc_rx_hist *h) 175{ 176 h->bytes_recvd = 0; 177 h->bytes_start = ktime_get_real(); 178} 179 180extern u32 tfrc_rx_hist_x_recv(struct tfrc_rx_hist *h, const u32 last_x_recv); 181 182 183extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h, 184 const struct sk_buff *skb, const u64 ndp); 185 186extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb); 187 188struct tfrc_loss_hist; 189extern bool tfrc_rx_congestion_event(struct tfrc_rx_hist *h, 190 struct tfrc_loss_hist *lh, 191 struct sk_buff *skb, const u64 ndp, 192 u32 (*first_li)(struct sock *sk), 193 struct sock *sk); 194extern void tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, 195 const struct sk_buff *skb); 196extern int tfrc_rx_hist_init(struct tfrc_rx_hist *h, struct sock *sk); 197extern void tfrc_rx_hist_purge(struct tfrc_rx_hist *h); 198 199#endif /* _DCCP_PKT_HIST_ */ 200