ntpdate.c

网络时间协议NTP 源码 版本v4.2.0b 该源码用于linux平台下

	 */
	for(nbsock = 0; (nbsock < MAX_AF) && res ; res = res->ai_next) {
	/* create a datagram (UDP) socket */
	   fd[nbsock] = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
	   if (fd[nbsock] == SOCKET_ERROR) {
#ifndef SYS_WINNT
		if (errno == EPROTONOSUPPORT || errno == EAFNOSUPPORT ||
		    errno == EPFNOSUPPORT)
#else
		int err = WSAGetLastError();
		if (err == WSAEPROTONOSUPPORT || err == WSAEAFNOSUPPORT ||
		    err == WSAEPFNOSUPPORT)
#endif
			continue;
		netsyslog(LOG_ERR, "socket() failed: %m");
		exit(1);
		/*NOTREACHED*/
	   }
	   /* set socket to reuse address */
	   if (setsockopt(fd[nbsock], SOL_SOCKET, SO_REUSEADDR, (void*) &optval, sizeof(optval)) < 0) {
		   netsyslog(LOG_ERR, "setsockopt() SO_REUSEADDR failed: %m");
		   exit(1);
		   /*NOTREACHED*/
	   }
#ifdef IPV6_V6ONLY
	   /* Restricts AF_INET6 socket to IPv6 communications (see RFC 2553bis-03) */
	   if (res->ai_family == AF_INET6)
		if (setsockopt(fd[nbsock], IPPROTO_IPV6, IPV6_V6ONLY, (void*) &optval, sizeof(optval)) < 0) {
			   netsyslog(LOG_ERR, "setsockopt() IPV6_V6ONLY failed: %m");
			   exit(1);
			   /*NOTREACHED*/
		}
#endif

	   /* Remember the socket family in fd_family structure */
	   fd_family[nbsock] = res->ai_family;

	/*
	 * bind the socket to the NTP port
	 */
	if (!debug && !simple_query && !unpriv_port) {
		if (bind(fd[nbsock], res->ai_addr, SOCKLEN(res->ai_addr)) < 0) {
#ifndef SYS_WINNT
			if (errno == EADDRINUSE)
#else
				if (WSAGetLastError() == WSAEADDRINUSE)
#endif /* SYS_WINNT */
				netsyslog(LOG_ERR,
					"the NTP socket is in use, exiting");
				else
				netsyslog(LOG_ERR, "bind() fails: %m");
			exit(1);
		}
	}

#ifdef HAVE_POLL_H
	    fdmask[nbsock].fd = fd[nbsock];
	    fdmask[nbsock].events = POLLIN;
#else
	    FD_SET(fd[nbsock], &fdmask);
	    if (maxfd < fd[nbsock]+1) {
		maxfd = fd[nbsock]+1;
	    }
#endif

	/*
	 * set non-blocking,
	 */
#ifndef SYS_WINNT
# ifdef SYS_VXWORKS
  {
	int on = TRUE;

	if (ioctl(fd[nbsock],FIONBIO, &on) == ERROR) {
	  netsyslog(LOG_ERR, "ioctl(FIONBIO) fails: %m");
	  exit(1);
	}
  }
# else /* not SYS_VXWORKS */
#  if defined(O_NONBLOCK)
	   if (fcntl(fd[nbsock], F_SETFL, O_NONBLOCK) < 0) {
		netsyslog(LOG_ERR, "fcntl(FNDELAY|FASYNC) fails: %m");
		exit(1);
		/*NOTREACHED*/
	}
#  else /* not O_NONBLOCK */
#	if defined(FNDELAY)
	   if (fcntl(fd[nbsock], F_SETFL, FNDELAY) < 0) {
		netsyslog(LOG_ERR, "fcntl(FNDELAY|FASYNC) fails: %m");
		exit(1);
		/*NOTREACHED*/
	}
#	else /* FNDELAY */
#	 include "Bletch: Need non blocking I/O"
#	endif /* FNDELAY */
#  endif /* not O_NONBLOCK */
# endif /* SYS_VXWORKS */
#else /* SYS_WINNT */
	if (ioctlsocket(fd[nbsock], FIONBIO, (u_long *) &on) == SOCKET_ERROR) {
		netsyslog(LOG_ERR, "ioctlsocket(FIONBIO) fails: %m");
		exit(1);
	}
#endif /* SYS_WINNT */
	nbsock++;
    }
    freeaddrinfo(ressave);
}

/*
 * sendpkt - send a packet to the specified destination
 */
static void
sendpkt(
	struct sockaddr_storage *dest,
	struct pkt *pkt,
	int len
	)
{
	int i;
	int cc;
	SOCKET sock = INVALID_SOCKET;

#ifdef SYS_WINNT
	DWORD err;
#endif /* SYS_WINNT */

	/* Find a local family compatible socket to send ntp packet to ntp server */
	for(i = 0; (i < MAX_AF); i++) {
		if(dest->ss_family == fd_family[i]) {
			sock = fd[i];
		break;
		}
	}

	if ( sock == INVALID_SOCKET ) {
		netsyslog(LOG_ERR, "cannot find family compatible socket to send ntp packet");
		exit(1);
		/*NOTREACHED*/
	}

	cc = sendto(sock, (char *)pkt, len, 0, (struct sockaddr *)dest,
			SOCKLEN(dest));

	if (cc == SOCKET_ERROR) {
#ifndef SYS_WINNT
		if (errno != EWOULDBLOCK && errno != ENOBUFS)
#else
		err = WSAGetLastError();
		if (err != WSAEWOULDBLOCK && err != WSAENOBUFS)
#endif /* SYS_WINNT */
			netsyslog(LOG_ERR, "sendto(%s): %m", stohost(dest));
	}
}


/*
 * input_handler - receive packets asynchronously
 */
void
input_handler(void)
{
	register int n;
	register struct recvbuf *rb;
	struct timeval tvzero;
	int fromlen;
	l_fp ts;
	SOCKET i;
#ifdef HAVE_POLL_H
	struct pollfd fds[MAX_AF];
#else
	fd_set fds;
#endif
	int fdc = 0;

	/*
	 * Do a poll to see if we have data
	 */
	for (;;) {
		tvzero.tv_sec = tvzero.tv_usec = 0;
#ifdef HAVE_POLL_H
		memcpy(fds, fdmask, sizeof(fdmask));
		n = poll(fds, (unsigned int)nbsock, tvzero.tv_sec * 1000);

		/*
		 * Determine which socket received data
		 */

		for(i=0; i < nbsock; i++) {
			if(fds[i].revents & POLLIN) {
				fdc = fd[i];
				break;
			}
		}

#else
		fds = fdmask;
		n = select(maxfd, &fds, (fd_set *)0, (fd_set *)0, &tvzero);

		/*
		 * Determine which socket received data
		 */

		for(i=0; i < maxfd; i++) {
			if(FD_ISSET(fd[i], &fds)) {
				 fdc = fd[i];
				 break;
			}
		}

#endif

		/*
		 * If nothing to do, just return.  If an error occurred,
		 * complain and return.  If we've got some, freeze a
		 * timestamp.
		 */
		if (n == 0)
			return;
		else if (n == -1) {
			if (errno != EINTR)
				netsyslog(LOG_ERR,
#ifdef HAVE_POLL_H
					"poll() error: %m"
#else
					"select() error: %m"
#endif
					);
			return;
		}
		get_systime(&ts);

		/*
		 * Get a buffer and read the frame.  If we
		 * haven't got a buffer, or this is received
		 * on the wild card socket, just dump the packet.
		 */
		if (initializing || free_recvbuffs() == 0) {
			char buf[100];


#ifndef SYS_WINNT
			(void) read(fdc, buf, sizeof buf);
#else
			/* NT's _read does not operate on nonblocking sockets
			 * either recvfrom or ReadFile() has to be used here.
			 * ReadFile is used in [ntpd]ntp_intres() and ntpdc,
			 * just to be different use recvfrom() here
			 */
			recvfrom(fdc, buf, sizeof(buf), 0, (struct sockaddr *)0, NULL);
#endif /* SYS_WINNT */
			continue;
		}

		rb = get_free_recv_buffer();

		fromlen = sizeof(struct sockaddr_storage);
		rb->recv_length = recvfrom(fdc, (char *)&rb->recv_pkt,
		   sizeof(rb->recv_pkt), 0,
		   (struct sockaddr *)&rb->recv_srcadr, &fromlen);
		if (rb->recv_length == -1) {
			freerecvbuf(rb);
			continue;
		}

		/*
		 * Got one.  Mark how and when it got here,
		 * put it on the full list.
		 */
		rb->recv_time = ts;
		add_full_recv_buffer(rb);
	}
}


#if !defined SYS_WINNT && !defined SYS_CYGWIN32
/*
 * adj_systime - do a big long slew of the system time
 */
static int
l_adj_systime(
	l_fp *ts
	)
{
	struct timeval adjtv, oadjtv;
	int isneg = 0;
	l_fp offset;
#ifndef STEP_SLEW
	l_fp overshoot;
#endif

	/*
	 * Take the absolute value of the offset
	 */
	offset = *ts;
	if (L_ISNEG(&offset)) {
		isneg = 1;
		L_NEG(&offset);
	}

#ifndef STEP_SLEW
	/*
	 * Calculate the overshoot.  XXX N.B. This code *knows*
	 * ADJ_OVERSHOOT is 1/2.
	 */
	overshoot = offset;
	L_RSHIFTU(&overshoot);
	if (overshoot.l_ui != 0 || (overshoot.l_uf > ADJ_MAXOVERSHOOT)) {
		overshoot.l_ui = 0;
		overshoot.l_uf = ADJ_MAXOVERSHOOT;
	}
	L_ADD(&offset, &overshoot);
#endif
	TSTOTV(&offset, &adjtv);

	if (isneg) {
		adjtv.tv_sec = -adjtv.tv_sec;
		adjtv.tv_usec = -adjtv.tv_usec;
	}

	if (adjtv.tv_usec != 0 && !debug) {
		if (adjtime(&adjtv, &oadjtv) < 0) {
			msyslog(LOG_ERR, "Can't adjust the time of day: %m");
			return 0;
		}
	}
	return 1;
}
#endif /* SYS_WINNT */


/*
 * This fuction is not the same as lib/systime step_systime!!!
 */
static int
l_step_systime(
	l_fp *ts
	)
{
	double dtemp;

#ifdef SLEWALWAYS
#ifdef STEP_SLEW
	l_fp ftmp;
	int isneg;
	int n;

	if (debug) return 1;
	/*
	 * Take the absolute value of the offset
	 */
	ftmp = *ts;
	if (L_ISNEG(&ftmp)) {
		L_NEG(&ftmp);
		isneg = 1;
	} else
		isneg = 0;

	if (ftmp.l_ui >= 3) {		/* Step it and slew - we might win */
		LFPTOD(ts, dtemp);
		n = step_systime(dtemp);
		if (!n)
			return n;
		if (isneg)
			ts->l_ui = ~0;
		else
			ts->l_ui = ~0;
	}
	/*
	 * Just add adjustment into the current offset.  The update
	 * routine will take care of bringing the system clock into
	 * line.
	 */
#endif
	if (debug)
		return 1;
#ifdef FORCE_NTPDATE_STEP
	LFPTOD(ts, dtemp);
	return step_systime(dtemp);
#else
	l_adj_systime(ts);
	return 1;
#endif
#else /* SLEWALWAYS */
	if (debug)
		return 1;
	LFPTOD(ts, dtemp);
	return step_systime(dtemp);
#endif	/* SLEWALWAYS */
}


/* XXX ELIMINATE printserver similar in ntptrace.c, ntpdate.c */
/*
 * printserver - print detail information for a server
 */
static void
printserver(
	register struct server *pp,
	FILE *fp
	)
{
	register int i;
	char junk[5];
	char *str;

	if (!debug) {
		(void) fprintf(fp, "server %s, stratum %d, offset %s, delay %s\n",
				   stoa(&pp->srcadr), pp->stratum,
				   lfptoa(&pp->offset, 6), fptoa((s_fp)pp->delay, 5));
		return;
	}

	(void) fprintf(fp, "server %s, port %d\n",
			   stoa(&pp->srcadr), ntohs(((struct sockaddr_in*)&(pp->srcadr))->sin_port));

	(void) fprintf(fp, "stratum %d, precision %d, leap %c%c, trust %03o\n",
			   pp->stratum, pp->precision,
			   pp->leap & 0x2 ? '1' : '0',
			   pp->leap & 0x1 ? '1' : '0',
			   pp->trust);

	if (pp->stratum == 1) {
		junk[4] = 0;
		memmove(junk, (char *)&pp->refid, 4);
		str = junk;
	} else {
		str = stoa(&pp->srcadr);
	}
	(void) fprintf(fp,
			   "refid [%s], delay %s, dispersion %s\n",
			   str, fptoa((s_fp)pp->delay, 5),
			   ufptoa(pp->dispersion, 5));

	(void) fprintf(fp, "transmitted %d, in filter %d\n",
			   pp->xmtcnt, pp->filter_nextpt);

	(void) fprintf(fp, "reference time:    %s\n",
			   prettydate(&pp->reftime));
	(void) fprintf(fp, "originate timestamp: %s\n",
			   prettydate(&pp->org));
	(void) fprintf(fp, "transmit timestamp:  %s\n",
			   prettydate(&pp->xmt));

	(void) fprintf(fp, "filter delay: ");
	for (i = 0; i < NTP_SHIFT; i++) {
		(void) fprintf(fp, " %-8.8s", fptoa(pp->filter_delay[i], 5));
		if (i == (NTP_SHIFT>>1)-1)
			(void) fprintf(fp, "\n        ");
	}
	(void) fprintf(fp, "\n");

	(void) fprintf(fp, "filter offset:");
	for (i = 0; i < PEER_SHIFT; i++) {
		(void) fprintf(fp, " %-8.8s", lfptoa(&pp->filter_offset[i], 6));
		if (i == (PEER_SHIFT>>1)-1)
			(void) fprintf(fp, "\n        ");
	}
	(void) fprintf(fp, "\n");

	(void) fprintf(fp, "delay %s, dispersion %s\n",
			   fptoa((s_fp)pp->delay, 5), ufptoa(pp->dispersion, 5));

	(void) fprintf(fp, "offset %s\n\n",
			   lfptoa(&pp->offset, 6));
}

#if !defined(HAVE_VSPRINTF)
int
vsprintf(
	char *str,
	const char *fmt,
	va_list ap
	)
{
	FILE f;
	int len;

	f._flag = _IOWRT+_IOSTRG;
	f._ptr = str;
	f._cnt = 32767;
	len = _doprnt(fmt, ap, &f);
	*f._ptr = 0;
	return (len);
}
#endif

#if 0
/* override function in library since SA_RESTART makes ALL syscalls restart */
#ifdef SA_RESTART
void
signal_no_reset(
	int sig,
	void (*func)()
	)
{
	int n;
	struct sigaction vec;

	vec.sa_handler = func;
	sigemptyset(&vec.sa_mask);
	vec.sa_flags = 0;

	while (1)
	{
		n = sigaction(sig, &vec, NULL);
		if (n == -1 && errno == EINTR)
			continue;
		break;
	}
	if (n == -1)
	{
		perror("sigaction");
		exit(1);
	}
}
#endif
#endif

#ifdef HAVE_NETINFO
static ni_namelist *
getnetinfoservers(void)
{
	ni_status status;
	void *domain;
	ni_id confdir;
	ni_namelist *namelist = (ni_namelist*)malloc(sizeof(ni_namelist));

	/* Find a time server in NetInfo */
	if ((status = ni_open(NULL, ".", &domain)) != NI_OK) return NULL;

	while (status = ni_pathsearch(domain, &confdir, NETINFO_CONFIG_DIR) == NI_NODIR) {
		void *next_domain;
		if (ni_open(domain, "..", &next_domain) != NI_OK) break;
		ni_free(domain);
		domain = next_domain;
	}
	if (status != NI_OK) return NULL;

	NI_INIT(namelist);
	if (ni_lookupprop(domain, &confdir, "server", namelist) != NI_OK) {
		ni_namelist_free(namelist);
		free(namelist);
		return NULL;
	}

	return(namelist);
}
#endif

#ifdef SYS_WINNT
isc_boolean_t ntp_port_inuse(int af, u_short port)
{
	/*
	 * Check if NTP socket is already in use on this system
	 * This is only for Windows Systems, as they tend not to fail on the real bind() below
	 */
	
	SOCKET checksocket;
	struct sockaddr_in checkservice;
	checksocket = socket(af, SOCK_DGRAM, 0);
	if (checksocket == INVALID_SOCKET) {
		return (ISC_TRUE);
	}

	checkservice.sin_family = (short) AF_INET;
	checkservice.sin_addr.s_addr = INADDR_LOOPBACK;
	checkservice.sin_port = htons(port);

	if (bind(checksocket, (struct sockaddr *)&checkservice,
		sizeof(checkservice)) == SOCKET_ERROR) {
		if ( WSAGetLastError() == WSAEADDRINUSE ){
			closesocket(checksocket);
			return (ISC_TRUE);
		}
	}
	closesocket(checksocket);
	return (ISC_FALSE);
}
#endif