nrelease: Install security/ca_root_nss explicitly (non-automatic).
[dragonfly.git] / sys / netinet / tcp_timer.h
blobbbe3e20618a6bebee10c0b916ad38da983fbc559
1 /*
2 * Copyright (c) 1982, 1986, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
29 * @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93
30 * $FreeBSD: src/sys/netinet/tcp_timer.h,v 1.18.2.1 2002/08/16 22:16:39 dillon Exp $
31 * $DragonFly: src/sys/netinet/tcp_timer.h,v 1.3 2003/08/23 11:18:00 rob Exp $
34 #ifndef _NETINET_TCP_TIMER_H_
35 #define _NETINET_TCP_TIMER_H_
38 * The TCPT_REXMT timer is used to force retransmissions.
39 * The TCP has the TCPT_REXMT timer set whenever segments
40 * have been sent for which ACKs are expected but not yet
41 * received. If an ACK is received which advances tp->snd_una,
42 * then the retransmit timer is cleared (if there are no more
43 * outstanding segments) or reset to the base value (if there
44 * are more ACKs expected). Whenever the retransmit timer goes off,
45 * we retransmit one unacknowledged segment, and do a backoff
46 * on the retransmit timer.
48 * The TCPT_PERSIST timer is used to keep window size information
49 * flowing even if the window goes shut. If all previous transmissions
50 * have been acknowledged (so that there are no retransmissions in progress),
51 * and the window is too small to bother sending anything, then we start
52 * the TCPT_PERSIST timer. When it expires, if the window is nonzero,
53 * we go to transmit state. Otherwise, at intervals send a single byte
54 * into the peer's window to force him to update our window information.
55 * We do this at most as often as TCPT_PERSMIN time intervals,
56 * but no more frequently than the current estimate of round-trip
57 * packet time. The TCPT_PERSIST timer is cleared whenever we receive
58 * a window update from the peer.
60 * The TCPT_KEEP timer is used to keep connections alive. If an
61 * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time,
62 * but not yet established, then we drop the connection. Once the connection
63 * is established, if the connection is idle for TCPTV_KEEP_IDLE time
64 * (and keepalives have been enabled on the socket), we begin to probe
65 * the connection. We force the peer to send us a segment by sending:
66 * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
67 * This segment is (deliberately) outside the window, and should elicit
68 * an ack segment in response from the peer. If, despite the TCPT_KEEP
69 * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
70 * amount of time probing, then we drop the connection.
74 * Time constants.
76 #define TCPTV_MSL ( 30*hz) /* max seg lifetime (hah!) */
77 #define TCPTV_SRTTBASE 0 /* base roundtrip time;
78 if 0, no idea yet */
79 #define TCPTV_RTOBASE3 ( 3*hz) /* assumed RTO if no info */
80 #define TCPTV_RTOBASE1 ( 1*hz) /* assumed RTO (RFC 6298) */
81 #define TCPTV_SRTTDFLT ( 3*hz) /* assumed RTT if no info */
83 #define TCPTV_PERSMIN ( 5*hz) /* retransmit persistence */
84 #define TCPTV_PERSMAX ( 60*hz) /* maximum persist interval */
86 #define TCPTV_KEEP_INIT ( 75*hz) /* initial connect keepalive */
87 #define TCPTV_KEEP_IDLE (120*60*hz) /* dflt time before probing */
88 #define TCPTV_KEEPINTVL ( 75*hz) /* default probe interval */
89 #define TCPTV_KEEPCNT 8 /* max probes before drop */
92 * Minimum retransmit timer is 3 ticks, for algorithmic stability.
93 * TCPT_RANGESET() will add another TCPTV_CPU_VAR to deal with
94 * the expected worst-case processing variances by the kernels
95 * representing the end points. Such variances do not always show
96 * up in the srtt because the timestamp is often calculated at
97 * the interface rather then at the TCP layer. This value is
98 * typically 50ms. However, it is also possible that delayed
99 * acks (typically 100ms) could create issues so we set the slop
100 * to ~160ms to try to cover it. Note that, properly speaking,
101 * delayed-acks should not create a major issue for interactive
102 * environments which 'P'ush the last segment, at least as
103 * long as implementations do the required 'at least one ack
104 * for every two packets' for the non-interactive streaming case.
106 * The prior minimum of 1*hz (1 second) badly breaks throughput
107 * on any networks faster then a modem that has minor (e.g. 1%)
108 * packet loss.
110 #define TCPTV_MIN ( hz/33 ) /* minimum allowable value */
111 #define TCPTV_CPU_VAR ( hz/6 ) /* cpu variance (~160ms) */
112 #define TCPTV_REXMTMAX ( 64*hz) /* max allowable REXMT value */
114 #define TCPTV_TWTRUNC 8 /* RTO factor to truncate TW */
116 #define TCP_LINGERTIME 120 /* linger at most 2 minutes */
118 #define TCP_MAXRXTSHIFT 12 /* maximum retransmits */
120 #define TCPTV_DELACK ( hz/10) /* 100ms timeout */
122 #ifdef TCPTIMERS
123 static const char *tcptimers[] =
124 { "REXMT", "PERSIST", "KEEP", "2MSL" };
125 #endif
128 * Force a time value to be in a certain range.
130 #define TCPT_RANGESET(tv, value, tvmin, tvmax) do { \
131 (tv) = (value) + tcp_rexmit_slop; \
132 if ((u_long)(tv) < (u_long)(tvmin)) \
133 (tv) = (tvmin); \
134 else if ((u_long)(tv) > (u_long)(tvmax)) \
135 (tv) = (tvmax); \
136 } while(0)
138 #ifdef _KERNEL
140 #define TCPTV_RTOBASE \
141 (tcp_low_rtobase ? TCPTV_RTOBASE1 : TCPTV_RTOBASE3)
143 struct tcpcb;
144 struct netmsg_tcp_timer {
145 struct netmsg_base tt_msg;
146 struct tcpcb *tt_tcb;
147 int tt_cpuid; /* owner cpuid */
148 lwkt_port_t tt_msgport; /* owner msgport */
149 uint32_t tt_tasks; /* pending tasks */
150 uint32_t tt_running_tasks; /* running tasks */
151 uint32_t tt_prev_tasks; /* prev pending tasks (debug) */
154 struct tcp_callout {
155 struct callout tc_callout;
156 uint32_t tc_task; /* callout's task id */
159 extern int tcp_keepinit; /* time to establish connection */
160 extern int tcp_keepidle; /* time before keepalive probes begin */
161 extern int tcp_keepintvl; /* time between keepalive probes */
162 extern int tcp_keepcnt; /* maximum number of keepalive probes */
163 extern int tcp_delacktime; /* time before sending a delayed ACK */
164 extern int tcp_maxpersistidle;
165 extern int tcp_rexmit_min;
166 extern int tcp_rexmit_slop;
167 extern int tcp_msl;
168 extern int tcp_ttl; /* time to live for TCP segs */
169 extern int tcp_backoff[]; /* rxt backoff for data */
170 extern int tcp_syn_backoff[]; /* rxt backoff for SYN */
171 extern int tcp_syn_backoff_low[]; /* rxt backoff for SYN w/ RFC6298 */
173 void tcp_timer_2msl(void *xtp);
174 void tcp_timer_keep(void *xtp);
175 void tcp_timer_persist(void *xtp);
176 void tcp_timer_rexmt(void *xtp);
177 void tcp_timer_delack(void *xtp);
178 void tcp_inittimers(struct tcpcb *);
180 struct lwkt_port;
181 void tcp_create_timermsg(struct tcpcb *, struct lwkt_port *);
182 void tcp_destroy_timermsg(struct tcpcb *);
184 #endif /* _KERNEL */
186 #endif /* !_NETINET_TCP_TIMER_H_ */