1 /*- 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 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 * 4. 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. 16 * 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. 28 * 29 * Copyright (c) 1995, Mike Mitchell 30 * 31 * Redistribution and use in source and binary forms, with or without 32 * modification, are permitted provided that the following conditions 33 * are met: 34 * 1. Redistributions of source code must retain the above copyright 35 * notice, this list of conditions and the following disclaimer. 36 * 2. Redistributions in binary form must reproduce the above copyright 37 * notice, this list of conditions and the following disclaimer in the 38 * documentation and/or other materials provided with the distribution. 39 * 3. All advertising materials mentioning features or use of this software 40 * must display the following acknowledgement: 41 * This product includes software developed by the University of 42 * California, Berkeley and its contributors. 43 * 4. Neither the name of the University nor the names of its contributors 44 * may be used to endorse or promote products derived from this software 45 * without specific prior written permission. 46 * 47 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 48 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 49 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 50 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 51 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 52 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 53 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 54 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 55 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 56 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 57 * SUCH DAMAGE. 58 * 59 * @(#)spx_timer.h 60 * 61 * $FreeBSD$ 62 */ 63 64 #ifndef _NETIPX_SPX_TIMER_H_ 65 #define _NETIPX_SPX_TIMER_H_ 66 67 /* 68 * Definitions of the SPX timers. These timers are counted 69 * down PR_SLOWHZ times a second. 70 */ 71 #define SPXT_REXMT 0 /* retransmit */ 72 #define SPXT_PERSIST 1 /* retransmit persistence */ 73 #define SPXT_KEEP 2 /* keep alive */ 74 #define SPXT_2MSL 3 /* 2*msl quiet time timer */ 75 76 /* 77 * The SPXT_REXMT timer is used to force retransmissions. 78 * The SPX has the SPXT_REXMT timer set whenever segments 79 * have been sent for which ACKs are expected but not yet 80 * received. If an ACK is received which advances tp->snd_una, 81 * then the retransmit timer is cleared (if there are no more 82 * outstanding segments) or reset to the base value (if there 83 * are more ACKs expected). Whenever the retransmit timer goes off, 84 * we retransmit one unacknowledged segment, and do a backoff 85 * on the retransmit timer. 86 * 87 * The SPXT_PERSIST timer is used to keep window size information 88 * flowing even if the window goes shut. If all previous transmissions 89 * have been acknowledged (so that there are no retransmissions in progress), 90 * and the window is too small to bother sending anything, then we start 91 * the SPXT_PERSIST timer. When it expires, if the window is nonzero, 92 * we go to transmit state. Otherwise, at intervals send a single byte 93 * into the peer's window to force him to update our window information. 94 * We do this at most as often as SPXT_PERSMIN time intervals, 95 * but no more frequently than the current estimate of round-trip 96 * packet time. The SPXT_PERSIST timer is cleared whenever we receive 97 * a window update from the peer. 98 * 99 * The SPXT_KEEP timer is used to keep connections alive. If an 100 * connection is idle (no segments received) for SPXTV_KEEP amount of time, 101 * but not yet established, then we drop the connection. If the connection 102 * is established, then we force the peer to send us a segment by sending: 103 * <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK> 104 * This segment is (deliberately) outside the window, and should elicit 105 * an ack segment in response from the peer. If, despite the SPXT_KEEP 106 * initiated segments we cannot elicit a response from a peer in SPXT_MAXIDLE 107 * amount of time, then we drop the connection. 108 */ 109 110 #define SPX_TTL 30 /* default time to live for SPX segs */ 111 /* 112 * Time constants. 113 */ 114 #define SPXTV_MSL ( 15*PR_SLOWHZ) /* max seg lifetime */ 115 #define SPXTV_SRTTBASE 0 /* base roundtrip time; 116 if 0, no idea yet */ 117 #define SPXTV_SRTTDFLT ( 3*PR_SLOWHZ) /* assumed RTT if no info */ 118 119 #define SPXTV_PERSMIN ( 5*PR_SLOWHZ) /* retransmit persistence */ 120 #define SPXTV_PERSMAX ( 60*PR_SLOWHZ) /* maximum persist interval */ 121 122 #define SPXTV_KEEP ( 75*PR_SLOWHZ) /* keep alive - 75 secs */ 123 #define SPXTV_MAXIDLE ( 8*SPXTV_KEEP) /* maximum allowable idle 124 time before drop conn */ 125 126 #define SPXTV_MIN ( 1*PR_SLOWHZ) /* minimum allowable value */ 127 #define SPXTV_REXMTMAX ( 64*PR_SLOWHZ) /* max allowable REXMT value */ 128 129 #define SPX_LINGERTIME 120 /* linger at most 2 minutes */ 130 131 #define SPX_MAXRXTSHIFT 12 /* maximum retransmits */ 132 133 #ifdef SPXTIMERS 134 char *spxtimers[] = 135 { "REXMT", "PERSIST", "KEEP", "2MSL" }; 136 #endif 137 138 /* 139 * Force a time value to be in a certain range. 140 */ 141 #define SPXT_RANGESET(tv, value, tvmin, tvmax) { \ 142 (tv) = (value); \ 143 if ((tv) < (tvmin)) \ 144 (tv) = (tvmin); \ 145 else if ((tv) > (tvmax)) \ 146 (tv) = (tvmax); \ 147 } 148 149 #endif /* !_NETIPX_SPX_TIMER_H_ */ 150