xref: /freebsd/sys/netinet/cc/cc.h (revision a03411e84728e9b267056fd31c7d1d9d1dc1b01e)
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 
39 /*
40  * This software was first released in 2007 by James Healy and Lawrence Stewart
41  * whilst working on the NewTCP research project at Swinburne University of
42  * Technology's Centre for Advanced Internet Architectures, Melbourne,
43  * Australia, which was made possible in part by a grant from the Cisco
44  * University Research Program Fund at Community Foundation Silicon Valley.
45  * More details are available at:
46  *   http://caia.swin.edu.au/urp/newtcp/
47  */
48 
49 #ifndef _NETINET_CC_CC_H_
50 #define _NETINET_CC_CC_H_
51 
52 #ifdef _KERNEL
53 
54 MALLOC_DECLARE(M_CC_MEM);
55 
56 /* Global CC vars. */
57 extern STAILQ_HEAD(cc_head, cc_algo) cc_list;
58 extern const int tcprexmtthresh;
59 
60 /* Per-netstack bits. */
61 VNET_DECLARE(struct cc_algo *, default_cc_ptr);
62 #define	V_default_cc_ptr VNET(default_cc_ptr)
63 
64 VNET_DECLARE(int, cc_do_abe);
65 #define	V_cc_do_abe			VNET(cc_do_abe)
66 
67 VNET_DECLARE(int, cc_abe_frlossreduce);
68 #define	V_cc_abe_frlossreduce		VNET(cc_abe_frlossreduce)
69 
70 /* Define the new net.inet.tcp.cc sysctl tree. */
71 #ifdef _SYS_SYSCTL_H_
72 SYSCTL_DECL(_net_inet_tcp_cc);
73 #endif
74 
75 /* For CC modules that use hystart++ */
76 extern uint32_t hystart_lowcwnd;
77 extern uint32_t hystart_minrtt_thresh;
78 extern uint32_t hystart_maxrtt_thresh;
79 extern uint32_t hystart_n_rttsamples;
80 extern uint32_t hystart_css_growth_div;
81 extern uint32_t hystart_css_rounds;
82 extern uint32_t hystart_bblogs;
83 
84 /* CC housekeeping functions. */
85 int	cc_register_algo(struct cc_algo *add_cc);
86 int	cc_deregister_algo(struct cc_algo *remove_cc);
87 #endif /* _KERNEL */
88 
89 #if defined(_KERNEL) || defined(_WANT_TCPCB)
90 /*
91  * Wrapper around transport structs that contain same-named congestion
92  * control variables. Allows algos to be shared amongst multiple CC aware
93  * transprots.
94  */
95 struct cc_var {
96 	void		*cc_data; /* Per-connection private CC algorithm data. */
97 	int		bytes_this_ack; /* # bytes acked by the current ACK. */
98 	tcp_seq		curack; /* Most recent ACK. */
99 	uint32_t	flags; /* Flags for cc_var (see below) */
100 	int		type; /* Indicates which ptr is valid in ccvc. */
101 	union ccv_container {
102 		struct tcpcb		*tcp;
103 		struct sctp_nets	*sctp;
104 	} ccvc;
105 	uint16_t	nsegs; /* # segments coalesced into current chain. */
106 	uint8_t		labc;  /* Dont use system abc use passed in */
107 };
108 
109 /* cc_var flags. */
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_USE_LOCAL_ABC       0x0004  /* Dont use the system l_abc val */
113 #define	CCF_ACKNOW		0x0008	/* Will this ack be sent now? */
114 #define	CCF_IPHDR_CE		0x0010	/* Does this packet set CE bit? */
115 #define	CCF_TCPHDR_CWR		0x0020	/* Does this packet set CWR bit? */
116 #define	CCF_MAX_CWND		0x0040	/* Have we reached maximum cwnd? */
117 #define	CCF_CHG_MAX_CWND	0x0080	/* CUBIC max_cwnd changed, for K */
118 #define	CCF_USR_IWND		0x0100	/* User specified initial window */
119 #define	CCF_USR_IWND_INIT_NSEG	0x0200	/* Convert segs to bytes on conn init */
120 #define CCF_HYSTART_ALLOWED	0x0400	/* If the CC supports it Hystart is allowed */
121 #define CCF_HYSTART_CAN_SH_CWND	0x0800  /* Can hystart when going CSS -> CA slam the cwnd */
122 #define CCF_HYSTART_CONS_SSTH	0x1000	/* Should hystart use the more conservative ssthresh */
123 
124 /* ACK types passed to the ack_received() hook. */
125 #define	CC_ACK		0x0001	/* Regular in sequence ACK. */
126 #define	CC_DUPACK	0x0002	/* Duplicate ACK. */
127 #define	CC_PARTIALACK	0x0004	/* Not yet. */
128 #define	CC_SACK		0x0008	/* Not yet. */
129 #endif /* defined(_KERNEL) || defined(_WANT_TCPCB) */
130 
131 /*
132  * Congestion signal types passed to the cong_signal() hook. The highest order 8
133  * bits (0x01000000 - 0x80000000) are reserved for CC algos to declare their own
134  * congestion signal types.
135  */
136 #define	CC_ECN		0x00000001	/* ECN marked packet received. */
137 #define	CC_RTO		0x00000002	/* RTO fired. */
138 #define	CC_RTO_ERR	0x00000004	/* RTO fired in error. */
139 #define	CC_NDUPACK	0x00000008	/* Threshold of dupack's reached. */
140 
141 #define	CC_SIGPRIVMASK	0xFF000000	/* Mask to check if sig is private. */
142 
143 #ifdef _KERNEL
144 /*
145  * Structure to hold data and function pointers that together represent a
146  * congestion control algorithm.
147  */
148 struct cc_algo {
149 	char	name[TCP_CA_NAME_MAX];
150 
151 	/* Init global module state on kldload. */
152 	int	(*mod_init)(void);
153 
154 	/* Cleanup global module state on kldunload. */
155 	int	(*mod_destroy)(void);
156 
157 	/* Return the size of the void pointer the CC needs for state */
158 	size_t  (*cc_data_sz)(void);
159 
160 	/*
161 	 * Init CC state for a new control block. The CC
162 	 * module may be passed a NULL ptr indicating that
163 	 * it must allocate the memory. If it is passed a
164 	 * non-null pointer it is pre-allocated memory by
165 	 * the caller and the cb_init is expected to use that memory.
166 	 * It is not expected to fail if memory is passed in and
167 	 * all currently defined modules do not.
168 	 */
169 	int	(*cb_init)(struct cc_var *ccv, void *ptr);
170 
171 	/* Cleanup CC state for a terminating control block. */
172 	void	(*cb_destroy)(struct cc_var *ccv);
173 
174 	/* Init variables for a newly established connection. */
175 	void	(*conn_init)(struct cc_var *ccv);
176 
177 	/* Called on receipt of an ack. */
178 	void	(*ack_received)(struct cc_var *ccv, uint16_t type);
179 
180 	/* Called on detection of a congestion signal. */
181 	void	(*cong_signal)(struct cc_var *ccv, uint32_t type);
182 
183 	/* Called after exiting congestion recovery. */
184 	void	(*post_recovery)(struct cc_var *ccv);
185 
186 	/* Called when data transfer resumes after an idle period. */
187 	void	(*after_idle)(struct cc_var *ccv);
188 
189 	/* Called for an additional ECN processing apart from RFC3168. */
190 	void	(*ecnpkt_handler)(struct cc_var *ccv);
191 
192 	/* Called when a new "round" begins, if the transport is tracking rounds.  */
193 	void	(*newround)(struct cc_var *ccv, uint32_t round_cnt);
194 
195 	/*
196 	 *  Called when a RTT sample is made (fas = flight at send, if you dont have it
197 	 *  send the cwnd in).
198 	 */
199 	void	(*rttsample)(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas);
200 
201 	/* Called for {get|set}sockopt() on a TCP socket with TCP_CCALGOOPT. */
202 	int     (*ctl_output)(struct cc_var *, struct sockopt *, void *);
203 
204 	STAILQ_ENTRY (cc_algo) entries;
205 	u_int	cc_refcount;
206 	uint8_t flags;
207 };
208 
209 #define CC_MODULE_BEING_REMOVED		0x01	/* The module is being removed */
210 
211 /* Macro to obtain the CC algo's struct ptr. */
212 #define	CC_ALGO(tp)	((tp)->t_cc)
213 
214 /* Macro to obtain the CC algo's data ptr. */
215 #define	CC_DATA(tp)	((tp)->t_ccv.cc_data)
216 
217 /* Macro to obtain the system default CC algo's struct ptr. */
218 #define	CC_DEFAULT_ALGO()	V_default_cc_ptr
219 
220 extern struct rwlock cc_list_lock;
221 #define	CC_LIST_LOCK_INIT()	rw_init(&cc_list_lock, "cc_list")
222 #define	CC_LIST_LOCK_DESTROY()	rw_destroy(&cc_list_lock)
223 #define	CC_LIST_RLOCK()		rw_rlock(&cc_list_lock)
224 #define	CC_LIST_RUNLOCK()	rw_runlock(&cc_list_lock)
225 #define	CC_LIST_WLOCK()		rw_wlock(&cc_list_lock)
226 #define	CC_LIST_WUNLOCK()	rw_wunlock(&cc_list_lock)
227 #define	CC_LIST_LOCK_ASSERT()	rw_assert(&cc_list_lock, RA_LOCKED)
228 
229 #define CC_ALGOOPT_LIMIT	2048
230 
231 /*
232  * These routines give NewReno behavior to the caller
233  * they require no state and can be used by any other CC
234  * module that wishes to use NewReno type behaviour (along
235  * with anything else they may add on, pre or post call).
236  */
237 void newreno_cc_post_recovery(struct cc_var *);
238 void newreno_cc_after_idle(struct cc_var *);
239 void newreno_cc_cong_signal(struct cc_var *, uint32_t );
240 void newreno_cc_ack_received(struct cc_var *, uint16_t);
241 
242 /* Called to temporarily keep an algo from going away during change */
243 void cc_refer(struct cc_algo *algo);
244 /* Called to release the temporary hold */
245 void cc_release(struct cc_algo *algo);
246 
247 /* Called to attach a CC algorithm to a tcpcb */
248 void cc_attach(struct tcpcb *, struct cc_algo *);
249 /* Called to detach a CC algorithm from a tcpcb */
250 void cc_detach(struct tcpcb *);
251 
252 #endif /* _KERNEL */
253 #endif /* _NETINET_CC_CC_H_ */
254