1 /* 2 * Copyright (c) 2007-2008 3 * Swinburne University of Technology, Melbourne, Australia. 4 * Copyright (c) 2009-2010 Lawrence Stewart <lstewart@freebsd.org> 5 * Copyright (c) 2010 The FreeBSD Foundation 6 * All rights reserved. 7 * Copyright (c) 2017 by Delphix. All rights reserved. 8 * 9 * This software was developed at the Centre for Advanced Internet 10 * Architectures, Swinburne University of Technology, by Lawrence Stewart and 11 * James Healy, made possible in part by a grant from the Cisco University 12 * Research Program Fund at Community Foundation Silicon Valley. 13 * 14 * Portions of this software were developed at the Centre for Advanced 15 * Internet Architectures, Swinburne University of Technology, Melbourne, 16 * Australia by David Hayes under sponsorship from the FreeBSD Foundation. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * $FreeBSD$ 40 */ 41 42 /* 43 * This software was first released in 2007 by James Healy and Lawrence Stewart 44 * whilst working on the NewTCP research project at Swinburne University of 45 * Technology's Centre for Advanced Internet Architectures, Melbourne, 46 * Australia, which was made possible in part by a grant from the Cisco 47 * University Research Program Fund at Community Foundation Silicon Valley. 48 * More details are available at: 49 * http://caia.swin.edu.au/urp/newtcp/ 50 */ 51 52 #ifndef _NETINET_CC_H_ 53 #define _NETINET_CC_H_ 54 55 #ifdef __cplusplus 56 extern "C" { 57 #endif 58 59 #include <netinet/tcp.h> 60 #include <sys/queue.h> 61 #include <sys/rwlock.h> 62 63 #define CC_ALGO_NAME_MAX 16 /* max congestion control name length */ 64 65 #define CC_DEFAULT_ALGO_NAME "sunreno" 66 67 struct tcp_s; 68 struct sctp_s; 69 70 /* CC housekeeping functions. */ 71 extern struct cc_algo *cc_load_algo(const char *name); 72 extern int cc_register_algo(struct cc_algo *add_cc); 73 extern int cc_deregister_algo(struct cc_algo *remove_cc); 74 75 /* 76 * Wrapper around transport structs that contain same-named congestion 77 * control variables. Allows algos to be shared amongst multiple CC aware 78 * transports. 79 * 80 * In theory, this code (from FreeBSD) can be used to support pluggable 81 * congestion control for sctp as well as tcp. However, the support for sctp 82 * in FreeBSD is incomplete, and in practice "type" is ignored. cc_module.h 83 * provides a CCV macro which implementations can use to get a variable out of 84 * the protocol-appropriate structure. 85 * 86 * If FreeBSD eventually does extend support for pluggable congestion control 87 * to sctp, we'll need to make sure we're setting "type" appropriately or use 88 * a definition of CCV that ignores it. 89 */ 90 struct cc_var { 91 void *cc_data; /* Per-connection private algorithm data. */ 92 int bytes_this_ack; /* # bytes acked by the current ACK. */ 93 int t_bytes_acked; /* # bytes acked during current RTT */ 94 tcp_seq curack; /* Most recent ACK. */ 95 uint32_t flags; /* Flags for cc_var (see below) */ 96 int type; /* Indicates which ptr is valid in ccvc. */ 97 union ccv_container { 98 struct tcp_s *tcp; 99 struct sctp_s *sctp; 100 } ccvc; 101 uint16_t nsegs; /* # segments coalesced into current chain. */ 102 }; 103 104 /* 105 * cc_var flags. 106 * 107 * CCF_ABC_SENTAWND is set when a full congestion window of data has been ACKed 108 * according to the Appropriate Byte Counting spec, defined in RFC 3465. 109 */ 110 #define CCF_ABC_SENTAWND 0x0001 /* ABC counted cwnd worth of bytes? */ 111 #define CCF_CWND_LIMITED 0x0002 /* Are we currently cwnd limited? */ 112 #define CCF_FASTRECOVERY 0x0004 /* in NewReno Fast Recovery */ 113 #define CCF_WASFRECOVERY 0x0008 /* was in NewReno Fast Recovery */ 114 #define CCF_CONGRECOVERY 0x0010 /* congestion recovery mode */ 115 #define CCF_WASCRECOVERY 0x0020 /* was in congestion recovery */ 116 /* 117 * In slow-start due to a retransmission timeout. This flag is enabled for the 118 * duration of the slow-start phase. 119 */ 120 #define CCF_RTO 0x0040 /* in slow-start due to timeout */ 121 122 #define IN_FASTRECOVERY(flags) (flags & CCF_FASTRECOVERY) 123 #define ENTER_FASTRECOVERY(flags) flags |= CCF_FASTRECOVERY 124 #define EXIT_FASTRECOVERY(flags) flags &= ~CCF_FASTRECOVERY 125 126 #define IN_CONGRECOVERY(flags) (flags & CCF_CONGRECOVERY) 127 #define ENTER_CONGRECOVERY(flags) flags |= CCF_CONGRECOVERY 128 #define EXIT_CONGRECOVERY(flags) flags &= ~CCF_CONGRECOVERY 129 130 #define IN_RECOVERY(flags) (flags & (CCF_CONGRECOVERY | CCF_FASTRECOVERY)) 131 #define ENTER_RECOVERY(flags) flags |= (CCF_CONGRECOVERY | CCF_FASTRECOVERY) 132 #define EXIT_RECOVERY(flags) flags &= ~(CCF_CONGRECOVERY | CCF_FASTRECOVERY) 133 134 /* 135 * ACK types passed to the ack_received() hook. 136 * 137 * CC_ACK is passed when an ACK acknowledges previously unACKed data. 138 * CC_DUPACK is passed when a duplicate ACK is received. The conditions under 139 * which an ACK is considered a duplicate ACK are defined in RFC 5681. 140 */ 141 #define CC_ACK 0x0001 /* Regular in sequence ACK. */ 142 #define CC_DUPACK 0x0002 /* Duplicate ACK. */ 143 #define CC_PARTIALACK 0x0004 /* Not yet. */ 144 #define CC_SACK 0x0008 /* Not yet. */ 145 146 /* 147 * Congestion signal types passed to the cong_signal() hook. The highest order 8 148 * bits (0x01000000 - 0x80000000) are reserved for CC algos to declare their own 149 * congestion signal types. 150 * 151 * The congestion signals defined here cover the following situations: 152 * CC_ECN: A packet with an Explicit Congestion Notification was received 153 * See RFC 3168. 154 * CC_RTO: A round-trip timeout occured. 155 * CC_RTO_ERR: An ACK was received for a sequence number after we fired an RTO 156 * for that sequence number 157 * CC_NDUPACK: Trigger fast retransmit based on the assumption that receiving 158 * N duplicate ACKs indicates packet loss rather than reordering. Fast 159 * retransmit is followed by fast recovery. Fast retransmit and recovery 160 * were originally described in RFC 2581 and were updated by RFC3782 161 * (NewReno). In both RFC2581 and RFC3782, N is 3. 162 */ 163 #define CC_ECN 0x00000001 /* ECN marked packet received. */ 164 #define CC_RTO 0x00000002 /* RTO fired. */ 165 #define CC_RTO_ERR 0x00000004 /* RTO fired in error. */ 166 #define CC_NDUPACK 0x00000008 /* Threshold of dupack's reached. */ 167 168 #define CC_SIGPRIVMASK 0xFF000000 /* Mask to check if sig is private. */ 169 170 /* 171 * Structure to hold data and function pointers that together represent a 172 * congestion control algorithm. 173 */ 174 struct cc_algo { 175 char name[CC_ALGO_NAME_MAX]; 176 177 /* Init CC state for a new control block. */ 178 int (*cb_init)(struct cc_var *ccv); 179 180 /* Cleanup CC state for a terminating control block. */ 181 void (*cb_destroy)(struct cc_var *ccv); 182 183 /* Init variables for a newly established connection. */ 184 void (*conn_init)(struct cc_var *ccv); 185 186 /* Called on receipt of an ack. */ 187 void (*ack_received)(struct cc_var *ccv, uint16_t type); 188 189 /* Called on detection of a congestion signal. */ 190 void (*cong_signal)(struct cc_var *ccv, uint32_t type); 191 192 /* Called after exiting congestion recovery. */ 193 void (*post_recovery)(struct cc_var *ccv); 194 195 /* Called when data transfer resumes after an idle period. */ 196 void (*after_idle)(struct cc_var *ccv); 197 198 STAILQ_ENTRY(cc_algo) entries; 199 }; 200 201 typedef int cc_walk_func_t(void *, struct cc_algo *); 202 extern int cc_walk_algos(cc_walk_func_t *, void *); 203 204 /* Macro to obtain the CC algo's struct ptr. */ 205 #define CC_ALGO(tp) ((tp)->tcp_cc_algo) 206 207 /* Macro to obtain the CC algo's data ptr. */ 208 #define CC_DATA(tp) ((tp)->tcp_ccv.cc_data) 209 210 #ifdef __cplusplus 211 } 212 #endif 213 214 #endif /* _NETINET_CC_H_ */ 215