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_ */