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

		       sizeof(struct in6_addr));
		((struct sockaddr_in6 *)&itf->sin)->sin6_port = port;

#ifdef ISC_PLATFORM_HAVESCOPEID
		((struct sockaddr_in6 *)&itf->sin)->sin6_scope_id = isc_netaddr_getzone(&isc_if->address);
		itf->scopeid = isc_netaddr_getzone(&isc_if->address);
#endif
		itf->mask.ss_family = itf->sin.ss_family;
		memcpy(&(((struct sockaddr_in6 *)&itf->mask)->sin6_addr),
		       &(isc_if->netmask.type.in6),
		       sizeof(struct in6_addr));
		((struct sockaddr_in6 *)&itf->mask)->sin6_port = port;

		if (((isc_if->flags & INTERFACE_F_LOOPBACK) != 0) && (loopback6_interface == NULL))
		{
			loopback6_interface = itf;
		}
		/* Copy the scopeid and the interface index */
		itf->ifindex = isc_if->ifindex;
	}
#endif /* INCLUDE_IPV6_SUPPORT */

		/* Process the rest of the flags */

	if((isc_if->flags & INTERFACE_F_UP) != 0)
		itf->flags |= INT_UP;
	if((isc_if->flags & INTERFACE_F_LOOPBACK) != 0)
		itf->flags |= INT_LOOPBACK;
	if((isc_if->flags & INTERFACE_F_POINTTOPOINT) != 0)
		itf->flags |= INT_PPP;
	if((isc_if->flags & INTERFACE_F_MULTICAST) != 0)
		itf->flags |= INT_MULTICAST;

}
/*
 * create_sockets - create a socket for each interface plus a default
 *			socket for when we don't know where to send
 */
static int
create_sockets(
	u_short port
	)
{
	struct sockaddr_storage resmask;
	int i;
	isc_mem_t *mctx = NULL;
	isc_interfaceiter_t *iter = NULL;
	isc_boolean_t scan_ipv4 = ISC_FALSE;
	isc_boolean_t scan_ipv6 = ISC_FALSE;
	isc_result_t result;
	int idx = 0;

#ifndef HAVE_IO_COMPLETION_PORT
	/*
	 * I/O Completion Ports don't care about the select and FD_SET
	 */
	maxactivefd = 0;
	FD_ZERO(&activefds);
#endif

#ifdef DEBUG
	if (debug)
	    printf("create_sockets(%d)\n", ntohs( (u_short) port));
#endif

#ifdef INCLUDE_IPV6_SUPPORT
	if (isc_net_probeipv6() == ISC_R_SUCCESS)
		scan_ipv6 = ISC_TRUE;
#if defined(DEBUG)
	else
		if(debug)
			netsyslog(LOG_ERR, "no IPv6 interfaces found");
#endif
#endif

	if (isc_net_probeipv4() == ISC_R_SUCCESS)
		scan_ipv4 = ISC_TRUE;
#ifdef DEBUG
	else
		if(debug)
			netsyslog(LOG_ERR, "no IPv4 interfaces found");
#endif
	/*
	 * Create wildcard addresses
	 * This ensures that no other application
	 * can be receiving ntp packets 
	 */

	nwilds = create_wildcards(port);
	idx = nwilds;

	result = isc_interfaceiter_create(mctx, &iter);
	if (result != ISC_R_SUCCESS)
		return (result);

	for (result = isc_interfaceiter_first(iter);
	     result == ISC_R_SUCCESS;
	     result = isc_interfaceiter_next(iter))
	{
		isc_interface_t isc_if;
		unsigned int family; 

		result = isc_interfaceiter_current(iter, &isc_if);
		if (result != ISC_R_SUCCESS)
			break;

		/* See if we have a valid family to use */
		family = isc_if.address.family;
		if (family != AF_INET && family != AF_INET6)
			continue;
		if (scan_ipv4 == ISC_FALSE && family == AF_INET)
			continue;
		if (scan_ipv6 == ISC_FALSE && family == AF_INET6)
			continue;

		/* 
		 * Check to see if we are going to use the interface
		 * If we don't use it we mark it to drop any packet
		 * received but we still must create the socket and
		 * bind to it. This prevents other apps binding to it
		 * and potentially causing problems with more than one
		 * process fiddling with the clock
		 */
		if (address_okay(&isc_if) == ISC_TRUE) {
			inter_list[idx].ignore_packets = ISC_FALSE;
		}
		else {
			inter_list[idx].ignore_packets = ISC_TRUE;
		}
		convert_isc_if(&isc_if, &inter_list[idx], port);
		inter_list[idx].fd = INVALID_SOCKET;
		inter_list[idx].bfd = INVALID_SOCKET;
		inter_list[idx].num_mcast = 0;
		inter_list[idx].received = 0;
		inter_list[idx].sent = 0;
		inter_list[idx].notsent = 0;
		idx++;
	}
	isc_interfaceiter_destroy(&iter);

	ninterfaces = idx;
	/*
	 * Create the sockets
	 */
	for (i = 0; i < ninterfaces; i++) {
		inter_list[i].fd = open_socket(&inter_list[i].sin,
		    inter_list[i].flags, 0, &inter_list[i], i);
		if (inter_list[i].fd != INVALID_SOCKET)
			msyslog(LOG_INFO, "Listening on interface %s, %s#%d %s",
				inter_list[i].name,
				stoa((&inter_list[i].sin)),
				NTP_PORT,
				(inter_list[i].ignore_packets == ISC_FALSE) ?
				"Enabled": "Disabled");
	/*
	 * Calculate the address hash for each interface address.
	 */
		inter_list[i].addr_refid = addr2refid(&inter_list[i].sin);
	}

	/*
	 * Now that we have opened all the sockets, turn off the reuse
	 * flag for security.
	 */
	set_reuseaddr(0);

	/*
	 * Blacklist all bound interface addresses
	 * Wildcard interfaces, if any, are ignored.
	 */

	for (i = nwilds; i < ninterfaces; i++) {
		SET_HOSTMASK(&resmask, inter_list[i].sin.ss_family);
		hack_restrict(RESTRICT_FLAGS, &inter_list[i].sin, &resmask,
		    RESM_NTPONLY|RESM_INTERFACE, RES_IGNORE);
	}


#ifdef DEBUG
	if (debug > 1) {
		printf("create_sockets: Total interfaces = %d\n", ninterfaces);
		for (i = 0; i < ninterfaces; i++) {
			print_interface(i);
		}
	}
#endif
	return ninterfaces;
}


/*
 * set_reuseaddr() - set/clear REUSEADDR on all sockets
 *			NB possible hole - should we be doing this on broadcast
 *			fd's also?
 */
static void
set_reuseaddr(int flag) {
	int i;

	for (i=0; i < ninterfaces; i++) {
		/*
		 * if inter_list[ n ].fd  is -1, we might have a adapter
		 * configured but not present
		 */
		if (inter_list[i].fd != INVALID_SOCKET) {
			if (setsockopt(inter_list[i].fd, SOL_SOCKET,
					SO_REUSEADDR, (char *)&flag,
					sizeof(flag))) {
				netsyslog(LOG_ERR, "set_reuseaddr: setsockopt(SO_REUSEADDR, %s) failed: %m", flag ? "on" : "off");
			}
		}
	}
}

/*
 * This is just a wrapper around an internal function so we can
 * make other changes as necessary later on
 */
void
enable_broadcast(struct interface *iface, struct sockaddr_storage *baddr)
{
#ifdef SO_BROADCAST
	socket_broadcast_enable(iface, iface->fd, baddr);
#endif
}

#ifdef OPEN_BCAST_SOCKET 
/*
 * Enable a broadcast address to a given socket
 * The socket is in the inter_list all we need to do is enable
 * broadcasting. It is not this function's job to select the socket
 */
static isc_boolean_t
socket_broadcast_enable(struct interface *iface, SOCKET fd, struct sockaddr_storage *maddr)
{
#ifdef SO_BROADCAST
	int on = 1;

	if (maddr->ss_family == AF_INET)
	{
		/* if this interface can support broadcast, set SO_BROADCAST */
		if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST,
			       (char *)&on, sizeof(on)))
		{
			netsyslog(LOG_ERR, "setsockopt(SO_BROADCAST) enable failure on address %s: %m",
				stoa(maddr));
		}
#ifdef DEBUG
		else if (debug > 1) {
			printf("Broadcast enabled on socket %d for address %s\n",
				fd, stoa(maddr));
		}
#endif
	}
	iface->flags |= INT_BCASTOPEN;
	modify_addr_in_list(maddr, iface->flags);
	return ISC_TRUE;
#else
	return ISC_FALSE;
#endif /* SO_BROADCAST */
}

/*
 * Remove a broadcast address from a given socket
 * The socket is in the inter_list all we need to do is disable
 * broadcasting. It is not this function's job to select the socket
 */
static isc_boolean_t
socket_broadcast_disable(struct interface *iface, int ind, struct sockaddr_storage *maddr)
{
#ifdef SO_BROADCAST
	int off = 0;

	if (maddr->ss_family == AF_INET)
	{
		if (setsockopt(iface->fd, SOL_SOCKET, SO_BROADCAST,
			       (char *)&off, sizeof(off)))
		{
			netsyslog(LOG_ERR, "setsockopt(SO_BROADCAST) disable failure on address %s: %m",
				stoa(maddr));
		}
	}
	iface->flags &= ~INT_BCASTOPEN;
	modify_addr_in_list(maddr, iface->flags);
	return ISC_TRUE;
#else
	return ISC_FALSE;
#endif /* SO_BROADCAST */
}

#endif /* OPEN_BCAST_SOCKET */
/*
 * Check to see if the address is a multicast address
 */
static isc_boolean_t
addr_ismulticast(struct sockaddr_storage *maddr)
{
	switch (maddr->ss_family)
	{
	case AF_INET :
		if (!IN_CLASSD(ntohl(((struct sockaddr_in*)maddr)->sin_addr.s_addr))) {
#ifdef DEBUG
			if (debug > 1)
				printf("multicast address %s not class D\n",
				stoa(maddr));
#endif
			return (ISC_FALSE);
		}
		else
		{
			return (ISC_TRUE);
		}
	case AF_INET6 :

#ifdef INCLUDE_IPV6_MULTICAST_SUPPORT
		if (!IN6_IS_ADDR_MULTICAST(&((struct sockaddr_in6*)maddr)->sin6_addr)) {
#ifdef DEBUG
			if (debug > 1)
				printf("address %s not IPv6 multicast address\n",
				stoa(maddr));
#endif
			return (ISC_FALSE);
		}
		else
		{
			return (ISC_TRUE);
		}

/*
 * If we don't have IPV6 support any IPV6 address is not multicast
 */
#else
		return (ISC_FALSE);
#endif
	/*
	 * Never valid
	 */
	default:
		return (ISC_FALSE);
	}
}
/*
 * Multicast servers need to set the appropriate Multicast interface
 * socket option in order for it to know which interface to use for
 * send the multicast packet.
 */
void
enable_multicast_if(struct interface *iface, struct sockaddr_storage *maddr)
{
#ifdef MCAST
	switch (maddr->ss_family)
	{
	case AF_INET:
		if (setsockopt(iface->fd, IPPROTO_IP, IP_MULTICAST_IF,
		   (char *)&(((struct sockaddr_in*)&iface->sin)->sin_addr.s_addr),
		    sizeof(struct sockaddr_in*)) == -1) {
			netsyslog(LOG_ERR,
			"setsockopt IP_MULTICAST_IF failure: %m on socket %d, addr %s for multicast address %s",
			iface->fd, stoa(&iface->sin), stoa(maddr));
			return;
		}
#ifdef DEBUG
		if (debug > 0) {
			printf(
			"Added IPv4 multicast interface on socket %d, addr %s for multicast address %s\n",
			iface->fd, stoa(&iface->sin),
			stoa(maddr));
		}
#endif
		break;
	case AF_INET6:
#ifdef INCLUDE_IPV6_MULTICAST_SUPPORT
		if (setsockopt(iface->fd, IPPROTO_IPV6, IPV6_MULTICAST_IF,
		    &iface->scopeid, sizeof(iface->scopeid)) == -1) {
			netsyslog(LOG_ERR,
			"setsockopt IPV6_MULTICAST_IF failure: %m on socket %d, addr %s, scope %d for multicast address %s",
			iface->fd, stoa(&iface->sin), iface->scopeid,
			stoa(maddr));
			return;
		}
#ifdef DEBUG
		if (debug > 0) {
			printf(
			"Added IPv6 multicast interface on socket %d, addr %s, scope %d for multicast address %s\n",
			iface->fd,  stoa(&iface->sin), iface->scopeid,
			stoa(maddr));
		}
#endif
		break;
#else
		return;
#endif	/* INCLUDE_IPV6_MULTICAST_SUPPORT */
	}
	return;
#endif
}
/*
 * NOTE: Not all platforms support multicast
 */
#ifdef MCAST
/*
 * Add a multicast address to a given socket
 * The socket is in the inter_list all we need to do is enable
 * multicasting. It is not this function's job to select the socket
 */
static isc_boolean_t
socket_multicast_enable(struct interface *iface, int ind, int lscope, struct sockaddr_storage *maddr)
{
#ifdef INCLUDE_IPV6_MULTICAST_SUPPORT
	struct ipv6_mreq mreq6;
	struct in6_addr iaddr6;
#endif /* INCLUDE_IPV6_MULTICAST_SUPPORT */
	struct ip_mreq mreq;

	switch (maddr->ss_family)
	{
	case AF_INET:
		memset((char *)&mreq, 0, sizeof(mreq));
		mreq.imr_multiaddr = (((struct sockaddr_in*)maddr)->sin_addr);
		mreq.imr_interface.s_addr = htonl(INADDR_ANY);
		if (setsockopt(iface->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP,
			(char *)&mreq, sizeof(mreq)) == -1) {
			netsyslog(LOG_ERR,
			"setsockopt IP_ADD_MEMBERSHIP failure: %m on socket %d, addr %s for %x / %x (%s)",
			iface->fd, stoa(&iface->sin),
			mreq.imr_multiaddr.s_addr,
			mreq.imr_interface.s_addr, stoa(maddr));
			return ISC_FALSE;
		}
#ifdef DEBUG
		if (debug > 0) {
			printf(
			"Added IPv4 multicast membership on socket %d, addr %s for %x / %x (%s)\n",
			iface->fd, stoa(&iface->sin),
			mreq.imr_multiaddr.s_addr,
			mreq.imr_interface.s_addr, stoa(maddr));
		}
#endif
		break;
	case AF_INET6:
#ifdef INCLUDE_IPV6_MULTICAST_SUPPORT

		/*
		 * Enable reception of multicast packets
		 * If the address is link-local we can get the interface index
		 * from the scope id. Don't do this for other types of multicast
		 * addresses. For now let the kernel figure it out.
		 */
		memset((char *)&mreq6, 0, sizeof(mreq6));
		iaddr6 = ((struct sockaddr_in6*)maddr)->sin6_addr;
		mreq6.ipv6mr_multiaddr = iaddr6;
		mreq6.ipv6mr_interface = lscope;

		if (setsockopt(iface->fd, IPPROTO_IPV6, IPV6_JOIN_GROUP,
			(char *)&mreq6, sizeof(mreq6)) == -1) {
			netsyslog(LOG_ERR,
			 "setsockopt IPV6_JOIN_GROUP failure: %m on socket %d, addr %s for interface %d(%s)",
			iface->fd, stoa(&iface->sin),
			mreq6.ipv6mr_interface, stoa(maddr));
			return ISC_FALSE;
		}
#ifdef DEBUG
		if (debug > 0) {
			printf(
			 "Added IPv6 multicast group on socket %d, addr %s for interface %d(%s)\n",
			iface->fd, stoa(&iface->sin),
			mreq6.ipv6mr_interface, stoa(maddr));
		}
#endif
		break;
#else
		return ISC_FALSE;
#endif	/* INCLUDE_IPV6_MULTICAST_SUPPORT */
	}
	iface->flags |= INT_MCASTOPEN;
	iface->num_mcast++;
	add_addr_to_list(maddr, ind, iface->flags);
	return ISC_TRUE;
}

/*
 * Remove a multicast address from a given socket
 * The socket is in the inter_list all we need to do is disable
 * multicasting. It is not this function's job to select the socket
 */
static isc_boolean_t
socket_multicast_disable(struct interface *iface, int ind, struct sockaddr_storage *maddr)
{
#ifdef INCLUDE_IPV6_MULTICAST_SUPPORT
	struct ipv6_mreq mreq6;
	struct in6_addr iaddr6;
#endif /* INCLUDE_IPV6_MULTICAST_SUPPORT */
	struct ip_mreq mreq;
	memset((char *)&mreq, 0, sizeof(mreq));

	switch (maddr->ss_family)
	{
	case AF_INET:
		mreq.imr_multiaddr = (((struct sockaddr_in*)&maddr)->sin_addr);
		mreq.imr_interface.s_addr = ((struct sockaddr_in*)&iface->sin)->sin_addr.s_addr;
		if (setsockopt(iface->fd, IPPROTO_IP, IP_DROP_MEMBERSHIP,
			(char *)&mreq, sizeof(mreq)) == -1) {
			netsyslog(LOG_ERR,
			"setsockopt IP_DROP_MEMBERSHIP failure: %m on socket %d, addr %s for %x / %x (%s)",
			iface->fd, stoa(&iface->sin),
			mreq.imr_multiaddr.s_addr,
			mreq.imr_interface.s_addr, stoa(maddr));
			return ISC_FALSE;
		}
		break;
	case AF_INET6:
#ifdef INCLUDE_IPV6_MULTICAST_SUPPORT

		/*
		 * Disable reception of multicast packets
		 * If the address is link-local we can get the interface index
		 * from the scope id. Don't do this for other types of multicast
		 * addresses. For now let the kernel figure it out.
		 */
		iaddr6 = ((struct sockaddr_in6*)&maddr)->sin6_addr;
		mreq6.ipv6mr_multiaddr = iaddr6;
		mreq6.ipv6mr_interface = iface->scopeid;

		if (setsockopt(iface->fd, IPPROTO_IPV6, IPV6_LEAVE_GROUP,
			(char *)&mreq6, sizeof(mreq6)) == -1) {