discover.c

DHCP服务器源码

				*sep = '\0';
			while (*name == ' ')
				name++;

			/* See if we've seen an interface that matches
			   this one. */
			for (tmp = interfaces; tmp; tmp = tmp -> next)
				if (!strcmp (tmp -> name, name))
					break;

			/* If we found one, nothing more to do.. */
			if (tmp)
				continue;

			/* Otherwise, allocate one. */
			tmp = (struct interface_info *)0;
			status = interface_allocate (&tmp, MDL);
			if (status != ISC_R_SUCCESS)
				log_fatal ("Can't allocate interface %s: %s",
					   name, isc_result_totext (status));
			tmp -> flags = ir;
			strncpy (tmp -> name, name, IFNAMSIZ);
			if (interfaces) {
				interface_reference (&tmp -> next,
						     interfaces, MDL);
				interface_dereference (&interfaces, MDL);
			}
			interface_reference (&interfaces, tmp, MDL);
			interface_dereference (&tmp, MDL);
			tmp = interfaces;

			if (dhcp_interface_discovery_hook)
				(*dhcp_interface_discovery_hook) (tmp);

		}
		fclose (proc_dev);
	}
#endif

	/* Now cycle through all the interfaces we found, looking for
	   hardware addresses. */
#if defined (HAVE_SIOCGIFHWADDR) && !defined (HAVE_AF_LINK)
	for (tmp = interfaces; tmp; tmp = tmp -> next) {
		struct ifreq ifr;
		struct sockaddr sa;
		int b, sk;
		
		if (!tmp -> ifp) {
			/* Make up an ifreq structure. */
			tif = (struct ifreq *)dmalloc (sizeof (struct ifreq),
						       MDL);
			if (!tif)
				log_fatal ("no space to remember ifp.");
			memset (tif, 0, sizeof (struct ifreq));
			strcpy (tif -> ifr_name, tmp -> name);
			tmp -> ifp = tif;
		}

		/* Read the hardware address from this interface. */
		ifr = *tmp -> ifp;
		if (ioctl (sock, SIOCGIFHWADDR, &ifr) < 0)
			continue;
		
		sa = *(struct sockaddr *)&ifr.ifr_hwaddr;
		
		switch (sa.sa_family) {
#ifdef HAVE_ARPHRD_TUNNEL
		      case ARPHRD_TUNNEL:
			/* ignore tunnel interfaces. */
#endif
#ifdef HAVE_ARPHRD_ROSE
		      case ARPHRD_ROSE:
#endif
#ifdef HAVE_ARPHRD_LOOPBACK
		      case ARPHRD_LOOPBACK:
			/* ignore loopback interface */
			break;
#endif

		      case ARPHRD_ETHER:
			tmp -> hw_address.hlen = 7;
			tmp -> hw_address.hbuf [0] = ARPHRD_ETHER;
			memcpy (&tmp -> hw_address.hbuf [1], sa.sa_data, 6);
			break;

#ifndef HAVE_ARPHRD_IEEE802
# define ARPHRD_IEEE802 HTYPE_IEEE802
#endif
#if defined (HAVE_ARPHRD_IEEE802_TR)
		      case ARPHRD_IEEE802_TR:
#endif
		      case ARPHRD_IEEE802:
			tmp -> hw_address.hlen = 7;
			tmp -> hw_address.hbuf [0] = ARPHRD_IEEE802;
			memcpy (&tmp -> hw_address.hbuf [1], sa.sa_data, 6);
			break;

#ifndef HAVE_ARPHRD_FDDI
# define ARPHRD_FDDI HTYPE_FDDI
#endif
		      case ARPHRD_FDDI:
			tmp -> hw_address.hlen = 17;
			tmp -> hw_address.hbuf [0] = HTYPE_FDDI; /* XXX */
			memcpy (&tmp -> hw_address.hbuf [1], sa.sa_data, 16);
			break;

#ifdef HAVE_ARPHRD_METRICOM
		      case ARPHRD_METRICOM:
			tmp -> hw_address.hlen = 7;
			tmp -> hw_address.hbuf [0] = ARPHRD_METRICOM;
			memcpy (&tmp -> hw_address.hbuf [0], sa.sa_data, 6);
			break;
#endif

#ifdef HAVE_ARPHRD_AX25
		      case ARPHRD_AX25:
			tmp -> hw_address.hlen = 7;
			tmp -> hw_address.hbuf [0] = ARPHRD_AX25;
			memcpy (&tmp -> hw_address.hbuf [1], sa.sa_data, 6);
			break;
#endif

#ifdef HAVE_ARPHRD_NETROM
		      case ARPHRD_NETROM:
			tmp -> hw_address.hlen = 7;
			tmp -> hw_address.hbuf [0] = ARPHRD_NETROM;
			memcpy (&tmp -> hw_address.hbuf [1], sa.sa_data, 6);
			break;
#endif

		      default:
			log_error ("%s: unknown hardware address type %d",
				   ifr.ifr_name, sa.sa_family);
			break;
		}
	}
#endif /* defined (HAVE_SIOCGIFHWADDR) && !defined (HAVE_AF_LINK) */

	/* If we're just trying to get a list of interfaces that we might
	   be able to configure, we can quit now. */
	if (state == DISCOVER_UNCONFIGURED) {
		close (sock);
		return;
	}

	/* Weed out the interfaces that did not have IP addresses. */
	tmp = last = next = (struct interface_info *)0;
	if (interfaces)
		interface_reference (&tmp, interfaces, MDL);
	while (tmp) {
		if (next)
			interface_dereference (&next, MDL);
		if (tmp -> next)
			interface_reference (&next, tmp -> next, MDL);
		/* skip interfaces that are running already */
		if (tmp -> flags & INTERFACE_RUNNING) {
			interface_dereference(&tmp, MDL);
			if(next)
				interface_reference(&tmp, next, MDL);
			continue;
		}
		if ((tmp -> flags & INTERFACE_AUTOMATIC) &&
		    state == DISCOVER_REQUESTED)
			tmp -> flags &= ~(INTERFACE_AUTOMATIC |
					  INTERFACE_REQUESTED);
		if (!tmp -> ifp || !(tmp -> flags & INTERFACE_REQUESTED)) {
			if ((tmp -> flags & INTERFACE_REQUESTED) != ir)
				log_fatal ("%s: not found", tmp -> name);
			if (!last) {
				if (interfaces)
					interface_dereference (&interfaces,
							       MDL);
				if (next)
				interface_reference (&interfaces, next, MDL);
			} else {
				interface_dereference (&last -> next, MDL);
				if (next)
					interface_reference (&last -> next,
							     next, MDL);
			}
			if (tmp -> next)
				interface_dereference (&tmp -> next, MDL);

			/* Remember the interface in case we need to know
			   about it later. */
			if (dummy_interfaces) {
				interface_reference (&tmp -> next,
						     dummy_interfaces, MDL);
				interface_dereference (&dummy_interfaces, MDL);
			}
			interface_reference (&dummy_interfaces, tmp, MDL);
			interface_dereference (&tmp, MDL);
			if (next)
				interface_reference (&tmp, next, MDL);
			continue;
		}
		last = tmp;

		memcpy (&foo, &tmp -> ifp -> ifr_addr,
			sizeof tmp -> ifp -> ifr_addr);

		/* We must have a subnet declaration for each interface. */
		if (!tmp -> shared_network && (state == DISCOVER_SERVER)) {
			log_error ("%s", "");
			log_error ("No subnet declaration for %s (%s).",
				   tmp -> name, inet_ntoa (foo.sin_addr));
			if (supports_multiple_interfaces (tmp)) {
				log_error ("** Ignoring requests on %s.  %s",
					   tmp -> name, "If this is not what");
				log_error ("   you want, please write %s",
					   "a subnet declaration");
				log_error ("   in your dhcpd.conf file %s",
					   "for the network segment");
				log_error ("   to %s %s %s",
					   "which interface",
					   tmp -> name, "is attached. **");
				log_error ("%s", "");
				goto next;
			} else {
				log_error ("You must write a subnet %s",
					   " declaration for this");
				log_error ("subnet.   You cannot prevent %s",
					   "the DHCP server");
				log_error ("from listening on this subnet %s",
					   "because your");
				log_fatal ("operating system does not %s.",
					   "support this capability");
			}
		}

		/* Find subnets that don't have valid interface
		   addresses... */
		for (subnet = (tmp -> shared_network
			       ? tmp -> shared_network -> subnets
			       : (struct subnet *)0);
		     subnet; subnet = subnet -> next_sibling) {
			if (!subnet -> interface_address.len) {
				/* Set the interface address for this subnet
				   to the first address we found. */
				subnet -> interface_address.len = 4;
				memcpy (subnet -> interface_address.iabuf,
					&foo.sin_addr.s_addr, 4);
			}
		}

		/* Flag the index as not having been set, so that the
		   interface registerer can set it or not as it chooses. */
		tmp -> index = -1;

		/* Register the interface... */
		if_register_receive (tmp);
		if_register_send (tmp);

		interface_stash (tmp);
		wifcount++;
#if defined (HAVE_SETFD)
		if (fcntl (tmp -> rfdesc, F_SETFD, 1) < 0)
			log_error ("Can't set close-on-exec on %s: %m",
				   tmp -> name);
		if (tmp -> rfdesc != tmp -> wfdesc) {
			if (fcntl (tmp -> wfdesc, F_SETFD, 1) < 0)
				log_error ("Can't set close-on-exec on %s: %m",
					   tmp -> name);
		}
#endif
	      next:
		interface_dereference (&tmp, MDL);
		if (next)
			interface_reference (&tmp, next, MDL);
	}

	/* Now register all the remaining interfaces as protocols. */
	for (tmp = interfaces; tmp; tmp = tmp -> next) {
		/* not if it's been registered before */
		if (tmp -> flags & INTERFACE_RUNNING)
			continue;
		if (tmp -> rfdesc == -1)
			continue;
		status = omapi_register_io_object ((omapi_object_t *)tmp,
						   if_readsocket, 0,
						   got_one, 0, 0);
		if (status != ISC_R_SUCCESS)
			log_fatal ("Can't register I/O handle for %s: %s",
				   tmp -> name, isc_result_totext (status));
	}

	close (sock);

	if (state == DISCOVER_SERVER && wifcount == 0) {
		log_info ("%s", "");
		log_fatal ("Not configured to listen on any interfaces!");
	}

	if (!setup_fallback) {
		setup_fallback = 1;
		maybe_setup_fallback ();
	}

#if defined (HAVE_SETFD)
	if (fallback_interface) {
	    if (fcntl (fallback_interface -> rfdesc, F_SETFD, 1) < 0)
		log_error ("Can't set close-on-exec on fallback: %m");
	    if (fallback_interface -> rfdesc != fallback_interface -> wfdesc) {
		if (fcntl (fallback_interface -> wfdesc, F_SETFD, 1) < 0)
		    log_error ("Can't set close-on-exec on fallback: %m");
	    }
	}
#endif
}

int if_readsocket (h)
	omapi_object_t *h;
{
	struct interface_info *ip;

	if (h -> type != dhcp_type_interface)
		return -1;
	ip = (struct interface_info *)h;
	return ip -> rfdesc;
}

int setup_fallback (struct interface_info **fp, const char *file, int line)
{
	isc_result_t status;

	status = interface_allocate (&fallback_interface, file, line);
	if (status != ISC_R_SUCCESS)
		log_fatal ("Error allocating fallback interface: %s",
			   isc_result_totext (status));
	strcpy (fallback_interface -> name, "fallback");
	if (dhcp_interface_setup_hook)
		(*dhcp_interface_setup_hook) (fallback_interface,
					      (struct iaddr *)0);
	status = interface_reference (fp, fallback_interface, file, line);

	fallback_interface -> index = -1;
	interface_stash (fallback_interface);
	return status == ISC_R_SUCCESS;
}

void reinitialize_interfaces ()
{
	struct interface_info *ip;

	for (ip = interfaces; ip; ip = ip -> next) {
		if_reinitialize_receive (ip);
		if_reinitialize_send (ip);
	}

	if (fallback_interface)
		if_reinitialize_send (fallback_interface);

	interfaces_invalidated = 1;
}

isc_result_t got_one (h)
	omapi_object_t *h;
{
	struct sockaddr_in from;
	struct hardware hfrom;
	struct iaddr ifrom;
	int result;
	union {
		unsigned char packbuf [4095]; /* Packet input buffer.
					 	 Must be as large as largest
						 possible MTU. */
		struct dhcp_packet packet;
	} u;
	struct interface_info *ip;

	if (h -> type != dhcp_type_interface)
		return ISC_R_INVALIDARG;
	ip = (struct interface_info *)h;

      again:
	if ((result =
	     receive_packet (ip, u.packbuf, sizeof u, &from, &hfrom)) < 0) {
		log_error ("receive_packet failed on %s: %m", ip -> name);
		return ISC_R_UNEXPECTED;
	}