1/* $NetBSD: tcp_congctl.h,v 1.7 2013/11/12 09:02:05 kefren Exp $ */
2
3/*
4 * Copyright (c) 2006 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Rui Paulo.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#ifndef _NETINET_TCP_CONGCTL_H
33#define _NETINET_TCP_CONGCTL_H
34
35#define TCPCC_MAXLEN 12
36
37struct tcp_congctlent {
38 TAILQ_ENTRY(tcp_congctlent) congctl_ent;
39 const struct tcp_congctl *congctl_ctl;
40 unsigned int congctl_refcnt;
41 char congctl_name[TCPCC_MAXLEN];
42};
43/*
44 * Congestion control function table.
45 */
46struct tcp_congctl {
47 /*
48 * fast_retransmit: called on tcprexmtthresh'th dup ACKs.
49 * this actually retransmits packets by calling tcp_output()
50 * if appropriate.
51 * returns 0 if entering fast recovery. otherwise returns non-0.
52 */
53 int (*fast_retransmit)(struct tcpcb *, const struct tcphdr *);
54
55 /*
56 * slow_retransmit: called on RTO to adjust parameters like cwnd.
57 */
58 void (*slow_retransmit)(struct tcpcb *);
59
60 /*
61 * fast_retransmit_newack: called when new data is acked.
62 * ie. when advancing SND.UNA
63 * not called if TCP_SACK_ENABLED.
64 */
65 void (*fast_retransmit_newack)(struct tcpcb *, const struct tcphdr *);
66
67 /*
68 * newack: called when new data is acked. ie. when advancing SND.UNA
69 * it's called before updating tp->snd_una.
70 */
71 void (*newack)(struct tcpcb *, const struct tcphdr *);
72
73 /*
74 * cong_exp: called when congestion is detected. eg. by ECN
75 */
76 void (*cong_exp)(struct tcpcb *);
77};
78
79extern const struct tcp_congctl tcp_reno_ctl;
80extern const struct tcp_congctl tcp_newreno_ctl;
81extern const struct tcp_congctl tcp_cubic_ctl;
82
83/* currently selected global congestion control */
84extern char tcp_congctl_global_name[TCPCC_MAXLEN];
85
86/* available global congestion control algorithms */
87extern char tcp_congctl_avail[10 * TCPCC_MAXLEN];
88
89void tcp_congctl_init(void);
90int tcp_congctl_register(const char *, const struct tcp_congctl *);
91int tcp_congctl_unregister(const char *);
92int tcp_congctl_select(struct tcpcb *, const char *);
93void tcp_congctl_release(struct tcpcb *);
94const char *
95 tcp_congctl_bystruct(const struct tcp_congctl *);
96
97#endif /* _NETINET_TCP_CONGCTL_H */
98