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 *
8 * This software was developed at the Centre for Advanced Internet
9 * Architectures, Swinburne University of Technology, by Lawrence Stewart and
10 * James Healy, made possible in part by a grant from the Cisco University
11 * Research Program Fund at Community Foundation Silicon Valley.
12 *
13 * Portions of this software were developed at the Centre for Advanced
14 * Internet Architectures, Swinburne University of Technology, Melbourne,
15 * Australia by David Hayes under sponsorship from the FreeBSD Foundation.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 *    notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 *    notice, this list of conditions and the following disclaimer in the
24 *    documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * $FreeBSD$
39 */
40
41/*
42 * This software was first released in 2007 by James Healy and Lawrence Stewart
43 * whilst working on the NewTCP research project at Swinburne University of
44 * Technology's Centre for Advanced Internet Architectures, Melbourne,
45 * Australia, which was made possible in part by a grant from the Cisco
46 * University Research Program Fund at Community Foundation Silicon Valley.
47 * More details are available at:
48 *   http://caia.swin.edu.au/urp/newtcp/
49 */
50
51#ifndef _NETINET_CC_H_
52#define _NETINET_CC_H_
53
54/* XXX: TCP_CA_NAME_MAX define lives in tcp.h for compat reasons. */
55#include <netinet/tcp.h>
56
57/* Global CC vars. */
58extern STAILQ_HEAD(cc_head, cc_algo) cc_list;
59extern const int tcprexmtthresh;
60extern struct cc_algo newreno_cc_algo;
61
62/* Per-netstack bits. */
63VNET_DECLARE(struct cc_algo *, default_cc_ptr);
64#define	V_default_cc_ptr VNET(default_cc_ptr)
65
66/* Define the new net.inet.tcp.cc sysctl tree. */
67SYSCTL_DECL(_net_inet_tcp_cc);
68
69/* CC housekeeping functions. */
70int	cc_register_algo(struct cc_algo *add_cc);
71int	cc_deregister_algo(struct cc_algo *remove_cc);
72
73/*
74 * Wrapper around transport structs that contain same-named congestion
75 * control variables. Allows algos to be shared amongst multiple CC aware
76 * transprots.
77 */
78struct cc_var {
79	void		*cc_data; /* Per-connection private CC algorithm data. */
80	int		bytes_this_ack; /* # bytes acked by the current ACK. */
81	tcp_seq		curack; /* Most recent ACK. */
82	uint32_t	flags; /* Flags for cc_var (see below) */
83	int		type; /* Indicates which ptr is valid in ccvc. */
84	union ccv_container {
85		struct tcpcb		*tcp;
86		struct sctp_nets	*sctp;
87	} ccvc;
88};
89
90/* cc_var flags. */
91#define	CCF_ABC_SENTAWND	0x0001	/* ABC counted cwnd worth of bytes? */
92#define	CCF_CWND_LIMITED	0x0002	/* Are we currently cwnd limited? */
93
94/* ACK types passed to the ack_received() hook. */
95#define	CC_ACK		0x0001	/* Regular in sequence ACK. */
96#define	CC_DUPACK	0x0002	/* Duplicate ACK. */
97#define	CC_PARTIALACK	0x0004	/* Not yet. */
98#define	CC_SACK		0x0008	/* Not yet. */
99
100/*
101 * Congestion signal types passed to the cong_signal() hook. The highest order 8
102 * bits (0x01000000 - 0x80000000) are reserved for CC algos to declare their own
103 * congestion signal types.
104 */
105#define	CC_ECN		0x00000001	/* ECN marked packet received. */
106#define	CC_RTO		0x00000002	/* RTO fired. */
107#define	CC_RTO_ERR	0x00000004	/* RTO fired in error. */
108#define	CC_NDUPACK	0x00000008	/* Threshold of dupack's reached. */
109
110#define	CC_SIGPRIVMASK	0xFF000000	/* Mask to check if sig is private. */
111
112/*
113 * Structure to hold data and function pointers that together represent a
114 * congestion control algorithm.
115 */
116struct cc_algo {
117	char	name[TCP_CA_NAME_MAX];
118
119	/* Init global module state on kldload. */
120	int	(*mod_init)(void);
121
122	/* Cleanup global module state on kldunload. */
123	int	(*mod_destroy)(void);
124
125	/* Init CC state for a new control block. */
126	int	(*cb_init)(struct cc_var *ccv);
127
128	/* Cleanup CC state for a terminating control block. */
129	void	(*cb_destroy)(struct cc_var *ccv);
130
131	/* Init variables for a newly established connection. */
132	void	(*conn_init)(struct cc_var *ccv);
133
134	/* Called on receipt of an ack. */
135	void	(*ack_received)(struct cc_var *ccv, uint16_t type);
136
137	/* Called on detection of a congestion signal. */
138	void	(*cong_signal)(struct cc_var *ccv, uint32_t type);
139
140	/* Called after exiting congestion recovery. */
141	void	(*post_recovery)(struct cc_var *ccv);
142
143	/* Called when data transfer resumes after an idle period. */
144	void	(*after_idle)(struct cc_var *ccv);
145
146	STAILQ_ENTRY (cc_algo) entries;
147};
148
149/* Macro to obtain the CC algo's struct ptr. */
150#define	CC_ALGO(tp)	((tp)->cc_algo)
151
152/* Macro to obtain the CC algo's data ptr. */
153#define	CC_DATA(tp)	((tp)->ccv->cc_data)
154
155/* Macro to obtain the system default CC algo's struct ptr. */
156#define	CC_DEFAULT()	V_default_cc_ptr
157
158extern struct rwlock cc_list_lock;
159#define	CC_LIST_LOCK_INIT()	rw_init(&cc_list_lock, "cc_list")
160#define	CC_LIST_LOCK_DESTROY()	rw_destroy(&cc_list_lock)
161#define	CC_LIST_RLOCK()		rw_rlock(&cc_list_lock)
162#define	CC_LIST_RUNLOCK()	rw_runlock(&cc_list_lock)
163#define	CC_LIST_WLOCK()		rw_wlock(&cc_list_lock)
164#define	CC_LIST_WUNLOCK()	rw_wunlock(&cc_list_lock)
165#define	CC_LIST_LOCK_ASSERT()	rw_assert(&cc_list_lock, RA_LOCKED)
166
167#endif /* _NETINET_CC_H_ */
168