ntp_io.c

网络时间协议NTP 源码 版本v4.2.0b 该源码用于linux平台下

			stoa(addr));
		exit(1);
		/*NOTREACHED*/
	}
#elif defined(FNDELAY)
	if (fcntl(fd, F_SETFL, FNDELAY) < 0)
	{
		netsyslog(LOG_ERR, "fcntl(FNDELAY) fails on address %s: %m",
			stoa(addr));
		exit(1);
		/*NOTREACHED*/
	}
#elif defined(O_NDELAY) /* generally the same as FNDELAY */
	if (fcntl(fd, F_SETFL, O_NDELAY) < 0)
	{
		netsyslog(LOG_ERR, "fcntl(O_NDELAY) fails on address %s: %m",
			stoa(addr));
		exit(1);
		/*NOTREACHED*/
	}
#elif defined(FIONBIO)
# if defined(SYS_WINNT)
		if (ioctlsocket(fd,FIONBIO,(u_long *) &on) == SOCKET_ERROR)
# else
		if (ioctl(fd,FIONBIO,&on) < 0)
# endif
	{
		netsyslog(LOG_ERR, "ioctl(FIONBIO) fails on address %s: %m",
			stoa(addr));
		exit(1);
		/*NOTREACHED*/
	}
#elif defined(FIOSNBIO)
	if (ioctl(fd,FIOSNBIO,&on) < 0)
	{
		netsyslog(LOG_ERR, "ioctl(FIOSNBIO) fails on address %s: %m",
			stoa(addr));
		exit(1);
		/*NOTREACHED*/
	}
#else
# include "Bletch: Need non-blocking I/O!"
#endif

#ifdef HAVE_SIGNALED_IO
	init_socket_sig(fd);
#endif /* not HAVE_SIGNALED_IO */

	/*
	 *	Turn off the SO_REUSEADDR socket option.  It apparently
	 *	causes heartburn on systems with multicast IP installed.
	 *	On normal systems it only gets looked at when the address
	 *	is being bound anyway..
	 */
	if (turn_off_reuse)
	    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
			   (char *)&off, sizeof(off)))
	    {
		    netsyslog(LOG_ERR, "setsockopt SO_REUSEADDR off fails on address %s: %m",
			    stoa(addr));
	    }

#if !defined(SYS_WINNT) && !defined(VMS)
# ifdef DEBUG
	if (debug > 1)
	    printf("flags for fd %d: 0%o\n", fd,
		   fcntl(fd, F_GETFL, 0));
# endif
#endif /* SYS_WINNT || VMS */


#if defined (HAVE_IO_COMPLETION_PORT)
/*
 * Add the socket to the completion port
 */
	io_completion_port_add_socket(fd, interf);
#endif
	return fd;
}


/*
 * close_socket - close a socket and remove from the activefd list
 */
static void
close_socket(
	     SOCKET fd
	)
{
	SOCKET i, newmax;

	if (fd < 0)
		return;

	(void) closesocket(fd);

	/*
	 * I/O Completion Ports don't care about select and fd_set
	 */
#ifndef HAVE_IO_COMPLETION_PORT
	FD_CLR( (u_int) fd, &activefds);

	if (fd == maxactivefd) {
		newmax = 0;
		for (i = 0; i < maxactivefd; i++)
			if (FD_ISSET(i, &activefds))
				newmax = i;
		maxactivefd = newmax;
	}
#endif
	delete_socket_from_list(fd);

}


/*
 * close_file - close a file and remove from the activefd list
 * added 1/31/1997 Greg Schueman for Windows NT portability
 */
#ifdef REFCLOCK
static void
close_file(
	SOCKET fd
	)
{
	int i, newmax;

	if (fd < 0)
		return;

	(void) close(fd);

#ifndef HAVE_IO_COMPLETION_PORT
	/*
	 * I/O Completion Ports don't care about select and fd_set
	 */
	FD_CLR( (u_int) fd, &activefds);

	if (fd == maxactivefd) {
		newmax = 0;
		for (i = 0; i < maxactivefd; i++)
			if (FD_ISSET(i, &activefds))
				newmax = i;
		maxactivefd = newmax;
	}
#endif
	delete_socket_from_list(fd);
}
#endif


/* XXX ELIMINATE sendpkt similar in ntpq.c, ntpdc.c, ntp_io.c, ntptrace.c */
/*
 * sendpkt - send a packet to the specified destination. Maintain a
 * send error cache so that only the first consecutive error for a
 * destination is logged.
 */
void
sendpkt(
	struct sockaddr_storage *dest,
	struct interface *inter,
	int ttl,
	struct pkt *pkt,
	int len
	)
{
	int cc, slot;
#ifdef SYS_WINNT
	DWORD err;
#endif /* SYS_WINNT */

	/*
	 * Send error caches. Empty slots have port == 0
	 * Set ERRORCACHESIZE to 0 to disable
	 */
	struct cache {
		u_short port;
		struct	in_addr addr;
	};

#ifdef INCLUDE_IPV6_SUPPORT
	struct cache6 {
		u_short port;
		struct in6_addr addr;
	};
#endif /* INCLUDE_IPV6_SUPPORT */

#ifndef ERRORCACHESIZE
#define ERRORCACHESIZE 8
#endif
#if ERRORCACHESIZE > 0
	static struct cache badaddrs[ERRORCACHESIZE];
#ifdef INCLUDE_IPV6_SUPPORT
	static struct cache6 badaddrs6[ERRORCACHESIZE];
#endif /* INCLUDE_IPV6_SUPPORT */
#else
#define badaddrs ((struct cache *)0)		/* Only used in empty loops! */
#ifdef INCLUDE_IPV6_SUPPORT
#define badaddrs6 ((struct cache6 *)0)		/* Only used in empty loops! */
#endif /* INCLUDE_IPV6_SUPPORT */
#endif
#ifdef DEBUG
	if (debug > 1)
	    printf("%ssendpkt(fd=%d dst=%s, src=%s, ttl=%d, len=%d)\n",
		   (ttl > 0) ? "\tMCAST\t*****" : "",
		   inter->fd, stoa(dest),
		   stoa(&inter->sin), ttl, len);
#endif

#ifdef MCAST

	switch (inter->sin.ss_family) {

	case AF_INET :

		/*
		* for the moment we use the bcast option to set multicast ttl
		*/
		if (ttl > 0 && ttl != inter->last_ttl) {

			/*
			* set the multicast ttl for outgoing packets
			*/
			u_char mttl = (u_char) ttl;
			if (setsockopt(inter->fd, IPPROTO_IP, IP_MULTICAST_TTL,
				(const void *) &mttl, sizeof(mttl)) != 0) {
				netsyslog(LOG_ERR, "setsockopt IP_MULTICAST_TTL fails on address %s: %m",
					stoa(&inter->sin));
			}
			else
   				inter->last_ttl = ttl;
		}
		break;

#ifdef INCLUDE_IPV6_SUPPORT
	case AF_INET6 :

	 	/*
		 * for the moment we use the bcast option to set
		 * multicast max hops
		 */
        	if (ttl > 0 && ttl != inter->last_ttl) {

                	/*
                 	* set the multicast ttl for outgoing packets
                 	*/
			u_int ittl = (u_int) ttl;
                	if (setsockopt(inter->fd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS,
                    	(const void *) &ittl, sizeof(ittl)) == -1)
	                        netsyslog(LOG_ERR, "setsockopt IP_MULTICAST_TTL fails on address %s: %m",
					stoa(&inter->sin));
                	else
	                        inter->last_ttl = ttl;
	        }
	        break;
#endif /* INCLUDE_IPV6_SUPPORT */

	default :
		exit(1);

	}


#endif /* MCAST */

	for (slot = ERRORCACHESIZE; --slot >= 0; )
		if(dest->ss_family == AF_INET) {
			if (badaddrs[slot].port == ((struct sockaddr_in*)dest)->sin_port &&
				badaddrs[slot].addr.s_addr == ((struct sockaddr_in*)dest)->sin_addr.s_addr)
			break;
		}
#ifdef INCLUDE_IPV6_SUPPORT
		else if (dest->ss_family == AF_INET6) {
			if (badaddrs6[slot].port == ((struct sockaddr_in6*)dest)->sin6_port &&
				badaddrs6[slot].addr.s6_addr == ((struct sockaddr_in6*)dest)->sin6_addr.s6_addr)
			break;
		}
#endif /* INCLUDE_IPV6_SUPPORT */
		else exit(1);  /* address family not supported yet */

#if defined(HAVE_IO_COMPLETION_PORT)
        err = io_completion_port_sendto(inter, pkt, len, dest);
	if (err != ERROR_SUCCESS)
#else
#ifdef SIM
        cc = srvr_rply(&ntp_node,  dest, inter, pkt);
#else /* SIM */
	cc = sendto(inter->fd, (char *)pkt, (unsigned int)len, 0, (struct sockaddr *)dest,
		    SOCKLEN(dest));
#endif /* SIM */
	if (cc == -1)
#endif
	{
		inter->notsent++;
		packets_notsent++;
#if defined(HAVE_IO_COMPLETION_PORT)
		err = WSAGetLastError();
		if (err != WSAEWOULDBLOCK && err != WSAENOBUFS && slot < 0)
#else
		if (errno != EWOULDBLOCK && errno != ENOBUFS && slot < 0)
#endif
		{
			/*
			 * Remember this, if there's an empty slot
			 */
			switch (dest->ss_family) {

			case AF_INET :

				for (slot = ERRORCACHESIZE; --slot >= 0; )
					if (badaddrs[slot].port == 0)
					{
						badaddrs[slot].port = SRCPORT(dest);
						badaddrs[slot].addr = ((struct sockaddr_in*)dest)->sin_addr;
						break;
					}
				break;

#ifdef INCLUDE_IPV6_SUPPORT
			case AF_INET6 :

				for (slot = ERRORCACHESIZE; --slot >= 0; )
        				if (badaddrs6[slot].port == 0)
            				{
                                    		badaddrs6[slot].port = SRCPORT(dest);
                                    		badaddrs6[slot].addr = ((struct sockaddr_in6*)dest)->sin6_addr;
                                    		break;
                            		}
                		break;
#endif /* INCLUDE_IPV6_SUPPORT */

			default :
				exit(1);
			}

			netsyslog(LOG_ERR, "sendto(%s) (fd=%d): %m",
				  stoa(dest), inter->fd);
		}
	}
	else
	{
		inter->sent++;
		packets_sent++;
		/*
		 * He's not bad any more
		 */
		if (slot >= 0)
		{
			netsyslog(LOG_INFO, "Connection re-established to %s", stoa(dest));
			switch (dest->ss_family) {
			case AF_INET :
				badaddrs[slot].port = 0;
				break;
#ifdef INCLUDE_IPV6_SUPPORT
			case AF_INET6 :
				badaddrs6[slot].port = 0;
				break;
#endif /* INCLUDE_IPV6_SUPPORT */
			}
		}
	}
}

#if !defined(HAVE_IO_COMPLETION_PORT)
/*
 * fdbits - generate ascii representation of fd_set (FAU debug support)
 * HFDF format - highest fd first.
 */
static char *
fdbits(
	int count,
	fd_set *set
	)
{
	static char buffer[256];
	char * buf = buffer;

	count = (count < 256) ? count : 255;

	while (count >= 0)
	{
		*buf++ = FD_ISSET(count, set) ? '#' : '-';
		count--;
	}
	*buf = '\0';

	return buffer;
}

/*
 * Routine to read the refclock packets for a specific interface
 * Return the number of bytes read. That way we know if we should
 * read it again or go on to the next one if no bytes returned
 */
static inline int
read_refclock_packet(SOCKET fd, struct refclockio *rp, l_fp ts)
{
	int i;
	int buflen;
	register struct recvbuf *rb;

	if (free_recvbuffs() == 0)
	{
		char buf[RX_BUFF_SIZE];

		buflen = read(fd, buf, sizeof buf);
		packets_dropped++;
		return (buflen);	/* Return what we found */
	}

	rb = get_free_recv_buffer();

	i = (rp->datalen == 0
	    || rp->datalen > sizeof(rb->recv_space))
	    ? sizeof(rb->recv_space) : rp->datalen;
	buflen = read(fd, (char *)&rb->recv_space, (unsigned)i);

	if (buflen < 0)
	{
		if (errno != EINTR && errno != EAGAIN) {
			netsyslog(LOG_ERR, "clock read fd %d: %m", fd);
		}
		freerecvbuf(rb);
		return (0);
	}
	/*
	 * Got one. Mark how and when it got here,
	 * put it on the full list and do bookkeeping.
	 */
	rb->recv_length = buflen;
	rb->recv_srcclock = rp->srcclock;
	rb->dstadr = 0;
	rb->fd = fd;
	rb->recv_time = ts;
	rb->receiver = rp->clock_recv;

	if (rp->io_input)
	{
		/*
		 * have direct input routine for refclocks
		 */
		if (rp->io_input(rb) == 0)
		{
			/*
			 * data was consumed - nothing to pass up
			 * into block input machine
			 */
			freerecvbuf(rb);
			return (buflen);
		}
	}
	
	add_full_recv_buffer(rb);

	rp->recvcount++;
	packets_received++;
	return (buflen);
}

/*
 * Routine to read the network NTP packets for a specific interface
 * Return the number of bytes read. That way we know if we should
 * read it again or go on to the next one if no bytes returned
 */
static inline int
read_network_packet(SOCKET fd, struct interface *itf, l_fp ts)
{
	int fromlen;
	int buflen;
	register struct recvbuf *rb;

	/*
	 * Get a buffer and read the frame.  If we
	 * haven't got a buffer, or this is received
	 * on a disallowed socket, just dump the
	 * packet.
	 */

	if (free_recvbuffs() == 0 || itf->ignore_packets == ISC_TRUE)
	{
		char buf[RX_BUFF_SIZE];
		struct sockaddr_storage from;
		fromlen = sizeof from;
		buflen = recvfrom(fd, buf, sizeof(buf), 0,
				(struct sockaddr*)&from, &fromlen);
#ifdef DEBUG
		if (debug > 3)
			printf("%s on (%lu) fd=%d from %s\n",
			(itf->ignore_packets == ISC_TRUE) ? "ignore" : "drop",
			free_recvbuffs(), fd,
			stoa(&from));
#endif
		if (itf->ignore_packets == ISC_TRUE)
			packets_ignored++;
		else
			packets_dropped++;
		return (buflen);
	}

	rb = get_free_recv_buffer();

	fromlen = sizeof(struct sockaddr_storage);
	rb->recv_length = recvfrom(fd,
			  (char *)&rb->recv_space,
			   sizeof(rb->recv_space), 0,
			   (struct sockaddr *)&rb->recv_srcadr,
			   &fromlen);
	if (rb->recv_length == 0|| (rb->recv_length == -1 && 
	    (errno==EWOULDBLOCK
#ifdef EAGAIN
	   || errno==EAGAIN
#endif
	 ))) {
		freerecvbuf(rb);
		return (rb->recv_length);
	}
	else if (rb->recv_length < 0)
	{
		netsyslog(LOG_ERR, "recvfrom(%s) fd=%d: %m",
		stoa(&rb->recv_srcadr), fd);
#ifdef DEBUG
		if (debug)
			printf("input_handler: fd=%d dropped (bad recvfrom)\n", fd);
#endif
		freerecvbuf(rb);