353 lines
8.7 KiB
C
353 lines
8.7 KiB
C
/*-
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* Copyright (c) 1985, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)measure.c 8.1 (Berkeley) 6/6/93";
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#endif
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static const char rcsid[] =
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"$Id: measure.c,v 1.4 1997/10/22 06:19:48 charnier Exp $";
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#endif /* not lint */
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#include "globals.h"
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_icmp.h>
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#define MSEC_DAY (SECDAY*1000)
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#define PACKET_IN 1024
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#define MSGS 5 /* timestamps to average */
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#define TRIALS 10 /* max # of timestamps sent */
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extern int sock_raw;
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int measure_delta;
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static n_short seqno = 0;
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/*
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* Measures the differences between machines' clocks using
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* ICMP timestamp messages.
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*/
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int /* status val defined in globals.h */
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measure(maxmsec, wmsec, hname, addr, print)
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u_long maxmsec; /* wait this many msec at most */
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u_long wmsec; /* msec to wait for an answer */
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char *hname;
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struct sockaddr_in *addr;
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int print; /* print complaints on stderr */
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{
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int length;
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int measure_status;
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int rcvcount, trials;
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int cc, count;
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fd_set ready;
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long sendtime, recvtime, histime1, histime2;
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long idelta, odelta, total;
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long min_idelta, min_odelta;
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struct timeval tdone, tcur, ttrans, twait, tout;
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u_char packet[PACKET_IN], opacket[64];
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register struct icmp *icp = (struct icmp *) packet;
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register struct icmp *oicp = (struct icmp *) opacket;
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struct ip *ip = (struct ip *) packet;
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min_idelta = min_odelta = 0x7fffffff;
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measure_status = HOSTDOWN;
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measure_delta = HOSTDOWN;
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errno = 0;
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/* open raw socket used to measure time differences */
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if (sock_raw < 0) {
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sock_raw = socket(AF_INET, SOCK_RAW, IPPROTO_ICMP);
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if (sock_raw < 0) {
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syslog(LOG_ERR, "opening raw socket: %m");
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goto quit;
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}
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}
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/*
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* empty the icmp input queue
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*/
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FD_ZERO(&ready);
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for (;;) {
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tout.tv_sec = tout.tv_usec = 0;
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FD_SET(sock_raw, &ready);
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if (select(sock_raw+1, &ready, 0,0, &tout)) {
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length = sizeof(struct sockaddr_in);
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cc = recvfrom(sock_raw, (char *)packet, PACKET_IN, 0,
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0,&length);
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if (cc < 0)
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goto quit;
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continue;
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}
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break;
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}
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/*
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* Choose the smallest transmission time in each of the two
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* directions. Use these two latter quantities to compute the delta
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* between the two clocks.
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*/
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oicp->icmp_type = ICMP_TSTAMP;
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oicp->icmp_code = 0;
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oicp->icmp_id = getpid();
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oicp->icmp_rtime = 0;
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oicp->icmp_ttime = 0;
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oicp->icmp_seq = seqno;
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FD_ZERO(&ready);
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#ifdef sgi
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sginap(1); /* start at a clock tick */
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#endif /* sgi */
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(void)gettimeofday(&tdone, 0);
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mstotvround(&tout, maxmsec);
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timevaladd(&tdone, &tout); /* when we give up */
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mstotvround(&twait, wmsec);
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rcvcount = 0;
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trials = 0;
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while (rcvcount < MSGS) {
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(void)gettimeofday(&tcur, 0);
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/*
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* keep sending until we have sent the max
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*/
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if (trials < TRIALS) {
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trials++;
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oicp->icmp_otime = htonl((tcur.tv_sec % SECDAY) * 1000
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+ tcur.tv_usec / 1000);
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oicp->icmp_cksum = 0;
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oicp->icmp_cksum = in_cksum((u_short*)oicp,
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sizeof(*oicp));
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count = sendto(sock_raw, opacket, sizeof(*oicp), 0,
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(struct sockaddr*)addr,
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sizeof(struct sockaddr));
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if (count < 0) {
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if (measure_status == HOSTDOWN)
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measure_status = UNREACHABLE;
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goto quit;
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}
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++oicp->icmp_seq;
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ttrans = tcur;
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timevaladd(&ttrans, &twait);
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} else {
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ttrans = tdone;
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}
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while (rcvcount < trials) {
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timevalsub(&tout, &ttrans, &tcur);
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if (tout.tv_sec < 0)
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tout.tv_sec = 0;
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FD_SET(sock_raw, &ready);
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count = select(sock_raw+1, &ready, (fd_set *)0,
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(fd_set *)0, &tout);
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(void)gettimeofday(&tcur, (struct timezone *)0);
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if (count <= 0)
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break;
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length = sizeof(struct sockaddr_in);
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cc = recvfrom(sock_raw, (char *)packet, PACKET_IN, 0,
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0,&length);
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if (cc < 0)
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goto quit;
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/*
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* got something. See if it is ours
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*/
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icp = (struct icmp *)(packet + (ip->ip_hl << 2));
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if (cc < sizeof(*ip)
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|| icp->icmp_type != ICMP_TSTAMPREPLY
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|| icp->icmp_id != oicp->icmp_id
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|| icp->icmp_seq < seqno
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|| icp->icmp_seq >= oicp->icmp_seq)
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continue;
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sendtime = ntohl(icp->icmp_otime);
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recvtime = ((tcur.tv_sec % SECDAY) * 1000 +
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tcur.tv_usec / 1000);
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total = recvtime-sendtime;
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if (total < 0) /* do not hassle midnight */
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continue;
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rcvcount++;
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histime1 = ntohl(icp->icmp_rtime);
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histime2 = ntohl(icp->icmp_ttime);
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/*
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* a host using a time format different from
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* msec. since midnight UT (as per RFC792) should
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* set the high order bit of the 32-bit time
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* value it transmits.
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*/
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if ((histime1 & 0x80000000) != 0) {
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measure_status = NONSTDTIME;
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goto quit;
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}
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measure_status = GOOD;
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idelta = recvtime-histime2;
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odelta = histime1-sendtime;
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/* do not be confused by midnight */
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if (idelta < -MSEC_DAY/2) idelta += MSEC_DAY;
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else if (idelta > MSEC_DAY/2) idelta -= MSEC_DAY;
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if (odelta < -MSEC_DAY/2) odelta += MSEC_DAY;
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else if (odelta > MSEC_DAY/2) odelta -= MSEC_DAY;
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/* save the quantization error so that we can get a
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* measurement finer than our system clock.
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*/
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if (total < MIN_ROUND) {
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measure_delta = (odelta - idelta)/2;
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goto quit;
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}
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if (idelta < min_idelta)
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min_idelta = idelta;
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if (odelta < min_odelta)
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min_odelta = odelta;
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measure_delta = (min_odelta - min_idelta)/2;
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}
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if (tcur.tv_sec > tdone.tv_sec
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|| (tcur.tv_sec == tdone.tv_sec
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&& tcur.tv_usec >= tdone.tv_usec))
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break;
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}
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quit:
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seqno += TRIALS; /* allocate our sequence numbers */
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/*
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* If no answer is received for TRIALS consecutive times,
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* the machine is assumed to be down
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*/
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if (measure_status == GOOD) {
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if (trace) {
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fprintf(fd,
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"measured delta %4d, %d trials to %-15s %s\n",
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measure_delta, trials,
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inet_ntoa(addr->sin_addr), hname);
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}
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} else if (print) {
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if (errno != 0)
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warn("measure %s", hname);
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} else {
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if (errno != 0) {
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syslog(LOG_ERR, "measure %s: %m", hname);
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} else {
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syslog(LOG_ERR, "measure: %s did not respond", hname);
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}
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if (trace) {
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fprintf(fd,
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"measure: %s failed after %d trials\n",
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hname, trials);
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(void)fflush(fd);
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}
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}
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return(measure_status);
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}
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/*
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* round a number of milliseconds into a struct timeval
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*/
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void
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mstotvround(res, x)
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struct timeval *res;
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long x;
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{
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#ifndef sgi
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if (x < 0)
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x = -((-x + 3)/5);
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else
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x = (x+3)/5;
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x *= 5;
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#endif /* sgi */
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res->tv_sec = x/1000;
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res->tv_usec = (x-res->tv_sec*1000)*1000;
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if (res->tv_usec < 0) {
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res->tv_usec += 1000000;
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res->tv_sec--;
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}
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}
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void
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timevaladd(tv1, tv2)
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struct timeval *tv1, *tv2;
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{
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tv1->tv_sec += tv2->tv_sec;
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tv1->tv_usec += tv2->tv_usec;
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if (tv1->tv_usec >= 1000000) {
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tv1->tv_sec++;
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tv1->tv_usec -= 1000000;
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}
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if (tv1->tv_usec < 0) {
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tv1->tv_sec--;
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tv1->tv_usec += 1000000;
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}
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}
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void
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timevalsub(res, tv1, tv2)
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struct timeval *res, *tv1, *tv2;
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{
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res->tv_sec = tv1->tv_sec - tv2->tv_sec;
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res->tv_usec = tv1->tv_usec - tv2->tv_usec;
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if (res->tv_usec >= 1000000) {
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res->tv_sec++;
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res->tv_usec -= 1000000;
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}
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if (res->tv_usec < 0) {
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res->tv_sec--;
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res->tv_usec += 1000000;
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}
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}
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