1 | /* $NetBSD: tcp_timer.h,v 1.28 2011/05/24 18:37:52 gdt Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 2001, 2005 The NetBSD Foundation, Inc. |
5 | * All rights reserved. |
6 | * |
7 | * This code is derived from software contributed to The NetBSD Foundation |
8 | * by Jason R. Thorpe of Wasabi Systems, Inc. |
9 | * This code is derived from software contributed to The NetBSD Foundation |
10 | * by Charles M. Hannum. |
11 | * |
12 | * Redistribution and use in source and binary forms, with or without |
13 | * modification, are permitted provided that the following conditions |
14 | * are met: |
15 | * 1. Redistributions of source code must retain the above copyright |
16 | * notice, this list of conditions and the following disclaimer. |
17 | * 2. Redistributions in binary form must reproduce the above copyright |
18 | * notice, this list of conditions and the following disclaimer in the |
19 | * documentation and/or other materials provided with the distribution. |
20 | * |
21 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
22 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
23 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
24 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
25 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
26 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
27 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
28 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
29 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
30 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
31 | * POSSIBILITY OF SUCH DAMAGE. |
32 | */ |
33 | |
34 | /* |
35 | * Copyright (c) 1982, 1986, 1993 |
36 | * The Regents of the University of California. All rights reserved. |
37 | * |
38 | * Redistribution and use in source and binary forms, with or without |
39 | * modification, are permitted provided that the following conditions |
40 | * are met: |
41 | * 1. Redistributions of source code must retain the above copyright |
42 | * notice, this list of conditions and the following disclaimer. |
43 | * 2. Redistributions in binary form must reproduce the above copyright |
44 | * notice, this list of conditions and the following disclaimer in the |
45 | * documentation and/or other materials provided with the distribution. |
46 | * 3. Neither the name of the University nor the names of its contributors |
47 | * may be used to endorse or promote products derived from this software |
48 | * without specific prior written permission. |
49 | * |
50 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
51 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
52 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
53 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
54 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
55 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
56 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
57 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
58 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
59 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
60 | * SUCH DAMAGE. |
61 | * |
62 | * @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93 |
63 | */ |
64 | |
65 | #ifndef _NETINET_TCP_TIMER_H_ |
66 | #define _NETINET_TCP_TIMER_H_ |
67 | |
68 | /* |
69 | * Definitions of the TCP timers. These timers are counted |
70 | * down PR_SLOWHZ times a second. |
71 | */ |
72 | #define TCPT_NTIMERS 4 |
73 | |
74 | #define TCPT_REXMT 0 /* retransmit */ |
75 | #define TCPT_PERSIST 1 /* retransmit persistance */ |
76 | #define TCPT_KEEP 2 /* keep alive */ |
77 | #define TCPT_2MSL 3 /* 2*msl quiet time timer */ |
78 | |
79 | /* |
80 | * The TCPT_REXMT timer is used to force retransmissions. |
81 | * The TCP has the TCPT_REXMT timer set whenever segments |
82 | * have been sent for which ACKs are expected but not yet |
83 | * received. If an ACK is received which advances tp->snd_una, |
84 | * then the retransmit timer is cleared (if there are no more |
85 | * outstanding segments) or reset to the base value (if there |
86 | * are more ACKs expected). Whenever the retransmit timer goes off, |
87 | * we retransmit one unacknowledged segment, and do a backoff |
88 | * on the retransmit timer. |
89 | * |
90 | * The TCPT_PERSIST timer is used to keep window size information |
91 | * flowing even if the window goes shut. If all previous transmissions |
92 | * have been acknowledged (so that there are no retransmissions in progress), |
93 | * and the window is too small to bother sending anything, then we start |
94 | * the TCPT_PERSIST timer. When it expires, if the window is nonzero, |
95 | * we go to transmit state. Otherwise, at intervals send a single byte |
96 | * into the peer's window to force him to update our window information. |
97 | * We do this at most as often as TCPT_PERSMIN time intervals, |
98 | * but no more frequently than the current estimate of round-trip |
99 | * packet time. The TCPT_PERSIST timer is cleared whenever we receive |
100 | * a window update from the peer. |
101 | * |
102 | * The TCPT_KEEP timer is used to keep connections alive. If an |
103 | * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time, |
104 | * but not yet established, then we drop the connection. Once the connection |
105 | * is established, if the connection is idle for TCPTV_KEEP_IDLE time |
106 | * (and keepalives have been enabled on the socket), we begin to probe |
107 | * the connection. We force the peer to send us a segment by sending: |
108 | * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK> |
109 | * This segment is (deliberately) outside the window, and should elicit |
110 | * an ack segment in response from the peer. If, despite the TCPT_KEEP |
111 | * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE |
112 | * amount of time probing, then we drop the connection. |
113 | */ |
114 | |
115 | /* |
116 | * Time constants. |
117 | * All TCPTV_* constants are in units of slow ticks (typically 500 ms). |
118 | */ |
119 | #define TCPTV_MSL ( 30*PR_SLOWHZ) /* max seg lifetime (hah!) */ |
120 | #define TCPTV_SRTTBASE 0 /* base roundtrip time; |
121 | if 0, no idea yet */ |
122 | #define TCPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */ |
123 | |
124 | #define TCPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistance */ |
125 | #define TCPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */ |
126 | |
127 | #define TCPTV_KEEP_INIT ( 75*PR_SLOWHZ) /* initial connect keep alive */ |
128 | #define TCPTV_KEEP_IDLE (120*60*PR_SLOWHZ) /* dflt time before probing */ |
129 | #define TCPTV_KEEPINTVL ( 75*PR_SLOWHZ) /* default probe interval */ |
130 | #define TCPTV_KEEPCNT 8 /* max probes before drop */ |
131 | |
132 | #define TCPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */ |
133 | #define TCPTV_REXMTMAX ( 64*PR_SLOWHZ) /* max allowable REXMT value */ |
134 | |
135 | #define TCP_LINGERTIME 120 /* linger at most 2 minutes */ |
136 | |
137 | #define TCP_MAXRXTSHIFT 12 /* maximum retransmits */ |
138 | |
139 | /* Acks are delayed for 1 second; constant is in fast ticks. */ |
140 | #define TCP_DELACK_TICKS (hz / PR_FASTHZ) /* time to delay ACK */ |
141 | |
142 | #ifdef TCPTIMERS |
143 | const char *tcptimers[] = |
144 | { "REXMT" , "PERSIST" , "KEEP" , "2MSL" }; |
145 | #endif |
146 | |
147 | /* |
148 | * Init, arm, disarm, and test TCP timers. |
149 | */ |
150 | #define TCP_TIMER_INIT(tp, timer) \ |
151 | callout_setfunc(&(tp)->t_timer[(timer)], \ |
152 | tcp_timer_funcs[(timer)], (tp)) |
153 | |
154 | /* |
155 | * nticks is given in units of slow timeouts, |
156 | * typically 500 ms (with PR_SLOWHZ at 2). |
157 | */ |
158 | #define TCP_TIMER_ARM(tp, timer, nticks) \ |
159 | callout_schedule(&(tp)->t_timer[(timer)], \ |
160 | (nticks) * (hz / PR_SLOWHZ)) |
161 | |
162 | #define TCP_TIMER_DISARM(tp, timer) \ |
163 | callout_stop(&(tp)->t_timer[(timer)]) |
164 | |
165 | #define TCP_TIMER_ISARMED(tp, timer) \ |
166 | callout_active(&(tp)->t_timer[(timer)]) |
167 | |
168 | /* |
169 | * Force a time value to be in a certain range. |
170 | */ |
171 | #define TCPT_RANGESET(tv, value, tvmin, tvmax) { \ |
172 | (tv) = (value); \ |
173 | if ((tv) < (tvmin)) \ |
174 | (tv) = (tvmin); \ |
175 | if ((tv) > (tvmax)) \ |
176 | (tv) = (tvmax); \ |
177 | } |
178 | |
179 | #ifdef _KERNEL |
180 | typedef void (*tcp_timer_func_t)(void *); |
181 | |
182 | extern const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS]; |
183 | |
184 | extern u_int tcp_keepinit; /* time before initial connection times out */ |
185 | extern u_int tcp_keepidle; /* time before keepalive probes begin */ |
186 | extern u_int tcp_keepintvl; /* time between keepalive probes */ |
187 | extern u_int tcp_keepcnt; /* number of keepalives, 0=infty */ |
188 | extern int tcp_maxpersistidle; /* max idle time in persist */ |
189 | extern int tcp_ttl; /* time to live for TCP segs */ |
190 | extern const int tcp_backoff[]; |
191 | |
192 | void tcp_timer_init(void); |
193 | #endif |
194 | |
195 | #endif /* !_NETINET_TCP_TIMER_H_ */ |
196 | |