Annotation of sys/netinet/tcp_timer.h, Revision 1.1
1.1 ! nbrk 1: /* $OpenBSD: tcp_timer.h,v 1.10 2003/06/02 23:28:15 millert Exp $ */
! 2: /* $NetBSD: tcp_timer.h,v 1.6 1995/03/26 20:32:37 jtc Exp $ */
! 3:
! 4: /*
! 5: * Copyright (c) 1982, 1986, 1993
! 6: * The Regents of the University of California. All rights reserved.
! 7: *
! 8: * Redistribution and use in source and binary forms, with or without
! 9: * modification, are permitted provided that the following conditions
! 10: * are met:
! 11: * 1. Redistributions of source code must retain the above copyright
! 12: * notice, this list of conditions and the following disclaimer.
! 13: * 2. Redistributions in binary form must reproduce the above copyright
! 14: * notice, this list of conditions and the following disclaimer in the
! 15: * documentation and/or other materials provided with the distribution.
! 16: * 3. Neither the name of the University nor the names of its contributors
! 17: * may be used to endorse or promote products derived from this software
! 18: * without specific prior written permission.
! 19: *
! 20: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
! 21: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! 22: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! 23: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
! 24: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
! 25: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
! 26: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
! 27: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
! 28: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
! 29: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
! 30: * SUCH DAMAGE.
! 31: *
! 32: * @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93
! 33: */
! 34:
! 35: #ifndef _NETINET_TCP_TIMER_H_
! 36: #define _NETINET_TCP_TIMER_H_
! 37:
! 38: /*
! 39: * Definitions of the TCP timers. These timers are counted
! 40: * down PR_SLOWHZ times a second.
! 41: */
! 42: #define TCPT_NTIMERS 4
! 43:
! 44: #define TCPT_REXMT 0 /* retransmit */
! 45: #define TCPT_PERSIST 1 /* retransmit persistance */
! 46: #define TCPT_KEEP 2 /* keep alive */
! 47: #define TCPT_2MSL 3 /* 2*msl quiet time timer */
! 48:
! 49: /*
! 50: * The TCPT_REXMT timer is used to force retransmissions.
! 51: * The TCP has the TCPT_REXMT timer set whenever segments
! 52: * have been sent for which ACKs are expected but not yet
! 53: * received. If an ACK is received which advances tp->snd_una,
! 54: * then the retransmit timer is cleared (if there are no more
! 55: * outstanding segments) or reset to the base value (if there
! 56: * are more ACKs expected). Whenever the retransmit timer goes off,
! 57: * we retransmit one unacknowledged segment, and do a backoff
! 58: * on the retransmit timer.
! 59: *
! 60: * The TCPT_PERSIST timer is used to keep window size information
! 61: * flowing even if the window goes shut. If all previous transmissions
! 62: * have been acknowledged (so that there are no retransmissions in progress),
! 63: * and the window is too small to bother sending anything, then we start
! 64: * the TCPT_PERSIST timer. When it expires, if the window is nonzero,
! 65: * we go to transmit state. Otherwise, at intervals send a single byte
! 66: * into the peer's window to force him to update our window information.
! 67: * We do this at most as often as TCPT_PERSMIN time intervals,
! 68: * but no more frequently than the current estimate of round-trip
! 69: * packet time. The TCPT_PERSIST timer is cleared whenever we receive
! 70: * a window update from the peer.
! 71: *
! 72: * The TCPT_KEEP timer is used to keep connections alive. If an
! 73: * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time,
! 74: * but not yet established, then we drop the connection. Once the connection
! 75: * is established, if the connection is idle for TCPTV_KEEP_IDLE time
! 76: * (and keepalives have been enabled on the socket), we begin to probe
! 77: * the connection. We force the peer to send us a segment by sending:
! 78: * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
! 79: * This segment is (deliberately) outside the window, and should elicit
! 80: * an ack segment in response from the peer. If, despite the TCPT_KEEP
! 81: * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
! 82: * amount of time probing, then we drop the connection.
! 83: */
! 84:
! 85: /*
! 86: * Time constants.
! 87: */
! 88: #define TCPTV_MSL ( 30*PR_SLOWHZ) /* max seg lifetime (hah!) */
! 89: #define TCPTV_SRTTBASE 0 /* base roundtrip time;
! 90: if 0, no idea yet */
! 91: #define TCPTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */
! 92:
! 93: #define TCPTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistance */
! 94: #define TCPTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */
! 95:
! 96: #define TCPTV_KEEP_INIT ( 75*PR_SLOWHZ) /* initial connect keep alive */
! 97: #define TCPTV_KEEP_IDLE (120*60*PR_SLOWHZ) /* dflt time before probing */
! 98: #define TCPTV_KEEPINTVL ( 75*PR_SLOWHZ) /* default probe interval */
! 99: #define TCPTV_KEEPCNT 8 /* max probes before drop */
! 100:
! 101: #define TCPTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */
! 102: #define TCPTV_REXMTMAX ( 64*PR_SLOWHZ) /* max allowable REXMT value */
! 103:
! 104: #define TCP_LINGERTIME 120 /* linger at most 2 minutes */
! 105:
! 106: #define TCP_MAXRXTSHIFT 12 /* maximum retransmits */
! 107:
! 108: #define TCP_DELACK_TICKS (hz / PR_FASTHZ) /* time to delay ACK */
! 109:
! 110: #ifdef TCPTIMERS
! 111: const char *tcptimers[] =
! 112: { "REXMT", "PERSIST", "KEEP", "2MSL" };
! 113: #endif /* TCPTIMERS */
! 114:
! 115: /*
! 116: * Init, arm, disarm, and test TCP timers.
! 117: */
! 118: #define TCP_TIMER_INIT(tp, timer) \
! 119: timeout_set(&(tp)->t_timer[(timer)], tcp_timer_funcs[(timer)], tp)
! 120:
! 121: #define TCP_TIMER_ARM(tp, timer, nticks) \
! 122: timeout_add(&(tp)->t_timer[(timer)], (nticks) * (hz / PR_SLOWHZ))
! 123:
! 124: #define TCP_TIMER_DISARM(tp, timer) \
! 125: timeout_del(&(tp)->t_timer[(timer)])
! 126:
! 127: #define TCP_TIMER_ISARMED(tp, timer) \
! 128: timeout_pending(&(tp)->t_timer[(timer)])
! 129:
! 130: /*
! 131: * Force a time value to be in a certain range.
! 132: */
! 133: #define TCPT_RANGESET(tv, value, tvmin, tvmax) { \
! 134: (tv) = (value); \
! 135: if ((tv) < (tvmin)) \
! 136: (tv) = (tvmin); \
! 137: else if ((tv) > (tvmax)) \
! 138: (tv) = (tvmax); \
! 139: }
! 140:
! 141: #ifdef _KERNEL
! 142: typedef void (*tcp_timer_func_t)(void *);
! 143:
! 144: extern const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS];
! 145:
! 146: extern int tcptv_keep_init;
! 147: extern int tcp_keepidle; /* time before keepalive probes begin */
! 148: extern int tcp_keepintvl; /* time between keepalive probes */
! 149: extern int tcp_maxidle; /* time to drop after starting probes */
! 150: extern int tcp_ttl; /* time to live for TCP segs */
! 151: extern int tcp_backoff[];
! 152:
! 153: void tcp_timer_init(void);
! 154: #endif /* _KERNEL */
! 155: #endif /* _NETINET_TCP_TIMER_H_ */
CVSweb
![[BACK]](/icons/back.gif){kind=icon}
Return to tcp_timer.h CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / sys / netinet