[thirdparty/dhcp.git] / common / discover.c

/* discover.c

   Find and identify the network interfaces. */

/*
 * Copyright (c) 2004-2008 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1995-2003 by Internet Software Consortium
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 *   Internet Systems Consortium, Inc.
 *   950 Charter Street
 *   Redwood City, CA 94063
 *   <info@isc.org>
 *   http://www.isc.org/
 *
 * This software has been written for Internet Systems Consortium
 * by Ted Lemon in cooperation with Vixie Enterprises and Nominum, Inc.
 * To learn more about Internet Systems Consortium, see
 * ``http://www.isc.org/''.  To learn more about Vixie Enterprises,
 * see ``http://www.vix.com''.   To learn more about Nominum, Inc., see
 * ``http://www.nominum.com''.
 */

#include "dhcpd.h"

#define BSD_COMP		/* needed on Solaris for SIOCGLIFNUM */
#include <sys/ioctl.h>
#include <errno.h>

#ifdef HAVE_NET_IF6_H
# include <net/if6.h>
#endif

struct interface_info *interfaces, *dummy_interfaces, *fallback_interface;
int interfaces_invalidated;
int quiet_interface_discovery;
u_int16_t local_port;
u_int16_t remote_port;
int (*dhcp_interface_setup_hook) (struct interface_info *, struct iaddr *);
int (*dhcp_interface_discovery_hook) (struct interface_info *);
isc_result_t (*dhcp_interface_startup_hook) (struct interface_info *);
int (*dhcp_interface_shutdown_hook) (struct interface_info *);

struct in_addr limited_broadcast;

int local_family = AF_INET;
struct in_addr local_address;

#ifdef DHCPv6
struct in6_addr local_address6;
#endif /* DHCPv6 */

void (*bootp_packet_handler) PROTO ((struct interface_info *,
				     struct dhcp_packet *, unsigned,
				     unsigned int,
				     struct iaddr, struct hardware *));

#ifdef DHCPv6
void (*dhcpv6_packet_handler)(struct interface_info *,
			      const char *, int,
			      int, const struct iaddr *,
			      isc_boolean_t);
#endif /* DHCPv6 */


omapi_object_type_t *dhcp_type_interface;
#if defined (TRACING)
trace_type_t *interface_trace;
trace_type_t *inpacket_trace;
trace_type_t *outpacket_trace;
#endif
struct interface_info **interface_vector;
int interface_count;
int interface_max;

OMAPI_OBJECT_ALLOC (interface, struct interface_info, dhcp_type_interface)

isc_result_t interface_setup ()
{
	isc_result_t status;
	status = omapi_object_type_register (&dhcp_type_interface,
					     "interface",
					     dhcp_interface_set_value,
					     dhcp_interface_get_value,
					     dhcp_interface_destroy,
					     dhcp_interface_signal_handler,
					     dhcp_interface_stuff_values,
					     dhcp_interface_lookup, 
					     dhcp_interface_create,
					     dhcp_interface_remove,
					     0, 0, 0,
					     sizeof (struct interface_info),
					     interface_initialize, RC_MISC);
	if (status != ISC_R_SUCCESS)
		log_fatal ("Can't register interface object type: %s",
			   isc_result_totext (status));

	return status;
}

#if defined (TRACING)
void interface_trace_setup ()
{
	interface_trace = trace_type_register ("interface", (void *)0,
					       trace_interface_input,
					       trace_interface_stop, MDL);
	inpacket_trace = trace_type_register ("inpacket", (void *)0,
					       trace_inpacket_input,
					       trace_inpacket_stop, MDL);
	outpacket_trace = trace_type_register ("outpacket", (void *)0,
					       trace_outpacket_input,
					       trace_outpacket_stop, MDL);
}
#endif

isc_result_t interface_initialize (omapi_object_t *ipo,
				   const char *file, int line)
{
	struct interface_info *ip = (struct interface_info *)ipo;
	ip -> rfdesc = ip -> wfdesc = -1;
	return ISC_R_SUCCESS;
}


/* 
 * Scanning for Interfaces
 * -----------------------
 *
 * To find interfaces, we create an iterator that abstracts out most 
 * of the platform specifics. Use is fairly straightforward:
 *
 * - begin_iface_scan() starts the process.
 * - Use next_iface() until it returns 0.
 * - end_iface_scan() performs any necessary cleanup.
 *
 * We check for errors on each call to next_iface(), which returns a
 * description of the error as a string if any occurs.
 *
 * We currently have code for Solaris and Linux. Other systems need
 * to have code written.
 *
 * NOTE: the long-term goal is to use the interface code from BIND 9.
 */

#if defined(SIOCGLIFCONF) && defined(SIOCGLIFNUM) && defined(SIOCGLIFFLAGS)

/* HP/UX doesn't define struct lifconf, instead they define struct
 * if_laddrconf.  Similarly, 'struct lifreq' and 'struct lifaddrreq'.
 */
#ifdef ISC_PLATFORM_HAVEIF_LADDRCONF
# define lifc_len iflc_len
# define lifc_buf iflc_buf
# define lifc_req iflc_req
# define LIFCONF if_laddrconf
#else
# define ISC_HAVE_LIFC_FAMILY 1
# define ISC_HAVE_LIFC_FLAGS 1
# define LIFCONF lifconf
#endif

#ifdef ISC_PLATFORM_HAVEIF_LADDRREQ
# define lifr_addr iflr_addr
# define lifr_name iflr_name
# define lifr_dstaddr iflr_dstaddr
# define lifr_flags iflr_flags
# define sockaddr_storage sockaddr_ext
# define ss_family sa_family
# define LIFREQ if_laddrreq
#else
# define LIFREQ lifreq
#endif

#ifndef IF_NAMESIZE
# if defined(LIFNAMSIZ)
#  define IF_NAMESIZE	LIFNAMSIZ
# elseif defined(IFNAMSIZ)
#  define IF_NAMESIZE	IFNAMSIZ
# else
#  define IF_NAMESIZE	16
# endif
#endif
#elif !defined(__linux) && !defined(HAVE_IFADDRS_H)
# define SIOCGLIFCONF SIOCGIFCONF
# define SIOCGLIFFLAGS SIOCGIFFLAGS
# define LIFREQ ifreq
# define LIFCONF ifconf
# define lifr_name ifr_name
# define lifr_addr ifr_addr
# define lifr_flags ifr_flags
# define lifc_len ifc_len
# define lifc_buf ifc_buf
# define lifc_req ifc_req
#ifdef _AIX
# define ss_family __ss_family
#endif
#endif

#if defined(SIOCGLIFCONF) && defined(SIOCGLIFFLAGS)
/* 
 * Solaris support
 * ---------------
 *
 * The SIOCGLIFCONF ioctl() are the extension that you need to use
 * on Solaris to get information about IPv6 addresses.
 *
 * Solaris' extended interface is documented in the if_tcp man page.
 */

/* 
 * Structure holding state about the scan.
 */
struct iface_conf_list {
	int sock;		/* file descriptor used to get information */
	int num;		/* total number of interfaces */
	struct LIFCONF conf;	/* structure used to get information */
	int next;		/* next interface to retrieve when iterating */
};

/* 
 * Structure used to return information about a specific interface.
 */
struct iface_info {
	char name[IF_NAMESIZE+1];	/* name of the interface, e.g. "bge0" */
	struct sockaddr_storage addr;	/* address information */
	isc_uint64_t flags;		/* interface flags, e.g. IFF_LOOPBACK */
};

/* 
 * Start a scan of interfaces.
 *
 * The iface_conf_list structure maintains state for this process.
 */
int 
begin_iface_scan(struct iface_conf_list *ifaces) {
#ifdef ISC_PLATFORM_HAVELIFNUM
	struct lifnum lifnum;
#else
	int lifnum;
#endif

	ifaces->sock = socket(local_family, SOCK_DGRAM, IPPROTO_UDP);
	if (ifaces->sock < 0) {
		log_error("Error creating socket to list interfaces; %m");
		return 0;
	}

	memset(&lifnum, 0, sizeof(lifnum));
#ifdef ISC_PLATFORM_HAVELIFNUM
	lifnum.lifn_family = AF_UNSPEC;
#endif
#ifdef SIOCGLIFNUM
	if (ioctl(ifaces->sock, SIOCGLIFNUM, &lifnum) < 0) {
		log_error("Error finding total number of interfaces; %m");
		close(ifaces->sock);
		ifaces->sock = -1;
		return 0;
	}

#ifdef ISC_PLATFORM_HAVELIFNUM
	ifaces->num = lifnum.lifn_count;
#else
	ifaces->num = lifnum;
#endif
#else
	ifaces->num = 64;
#endif /* SIOCGLIFNUM */

	memset(&ifaces->conf, 0, sizeof(ifaces->conf));
#ifdef ISC_HAVE_LIFC_FAMILY
	ifaces->conf.lifc_family = AF_UNSPEC;
#endif
	ifaces->conf.lifc_len = ifaces->num * sizeof(struct LIFREQ);
	ifaces->conf.lifc_buf = dmalloc(ifaces->conf.lifc_len, MDL);
	if (ifaces->conf.lifc_buf == NULL) {
		log_fatal("Out of memory getting interface list.");
	}

	if (ioctl(ifaces->sock, SIOCGLIFCONF, &ifaces->conf) < 0) {
		log_error("Error getting interfaces configuration list; %m");
		dfree(ifaces->conf.lifc_buf, MDL);
		close(ifaces->sock);
		ifaces->sock = -1;
		return 0;
	}

	ifaces->next = 0;

	return 1;
}

/*
 * Retrieve the next interface.
 *
 * Returns information in the info structure. 
 * Sets err to 1 if there is an error, otherwise 0.
 */
int
next_iface(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
	struct LIFREQ *p;
	struct LIFREQ tmp;
#if defined(sun) || defined(__linux)
	/* Pointer used to remove interface aliases. */
	char *s;
#endif

	do {
		if (ifaces->next >= ifaces->num) {
			*err = 0;
			return 0;
		}

		p = ifaces->conf.lifc_req;
		p += ifaces->next;

		if (strlen(p->lifr_name) >= sizeof(info->name)) {
			*err = 1;
			log_error("Interface name '%s' too long", p->lifr_name);
			return 0;
		}
		strcpy(info->name, p->lifr_name);
		memset(&info->addr, 0, sizeof(info->addr));
		memcpy(&info->addr, &p->lifr_addr, sizeof(p->lifr_addr));

#if defined(sun) || defined(__linux)
		/* interface aliases look like "eth0:1" or "wlan1:3" */
		s = strchr(info->name, ':');
		if (s != NULL) {
			*s = '\0';
		}
#endif /* defined(sun) || defined(__linux) */

	} while (strncmp(info->name, "dummy", 5) == 0);
	
	memset(&tmp, 0, sizeof(tmp));
	strcpy(tmp.lifr_name, info->name);
	if (ioctl(ifaces->sock, SIOCGLIFFLAGS, &tmp) < 0) {
		log_error("Error getting interface flags for '%s'; %m", 
			  p->lifr_name);
		*err = 1;
		return 0;
	}
	info->flags = tmp.lifr_flags;

	ifaces->next++;
	*err = 0;
	return 1;
}

/*
 * End scan of interfaces.
 */
void
end_iface_scan(struct iface_conf_list *ifaces) {
	dfree(ifaces->conf.lifc_buf, MDL);
	close(ifaces->sock);
	ifaces->sock = -1;
}

#elif __linux /* !HAVE_SIOCGLIFCONF */
/* 
 * Linux support
 * -------------
 *
 * In Linux, we use the /proc pseudo-filesystem to get information
 * about interfaces, along with selected ioctl() calls.
 *
 * Linux low level access is documented in the netdevice man page.
 */

/* 
 * Structure holding state about the scan.
 */
struct iface_conf_list {
	int sock;	/* file descriptor used to get information */
	FILE *fp;	/* input from /proc/net/dev */
#ifdef DHCPv6
	FILE *fp6;	/* input from /proc/net/if_inet6 */
#endif
};

/* 
 * Structure used to return information about a specific interface.
 */
struct iface_info {
	char name[IFNAMSIZ];		/* name of the interface, e.g. "eth0" */
	struct sockaddr_storage addr;	/* address information */
	isc_uint64_t flags;		/* interface flags, e.g. IFF_LOOPBACK */
};

/* 
 * Start a scan of interfaces.
 *
 * The iface_conf_list structure maintains state for this process.
 */
int 
begin_iface_scan(struct iface_conf_list *ifaces) {
	char buf[256];
	int len;
	int i;

	ifaces->fp = fopen("/proc/net/dev", "r");
	if (ifaces->fp == NULL) {
		log_error("Error opening '/proc/net/dev' to list interfaces");
		return 0;
	}

	/*
	 * The first 2 lines are header information, so read and ignore them.
	 */
	for (i=0; i<2; i++) {
		if (fgets(buf, sizeof(buf), ifaces->fp) == NULL) {
			log_error("Error reading headers from '/proc/net/dev'");
			fclose(ifaces->fp);
			ifaces->fp = NULL;
			return 0;
		}
		len = strlen(buf);
		if ((len <= 0) || (buf[len-1] != '\n')) { 
			log_error("Bad header line in '/proc/net/dev'");
			fclose(ifaces->fp);
			ifaces->fp = NULL;
			return 0;
		}
	}

	ifaces->sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (ifaces->sock < 0) {
		log_error("Error creating socket to list interfaces; %m");
		fclose(ifaces->fp);
		ifaces->fp = NULL;
		return 0;
	}

#ifdef DHCPv6
	ifaces->fp6 = fopen("/proc/net/if_inet6", "r");
	if (ifaces->fp6 == NULL) {
		log_error("Error opening '/proc/net/if_inet6' to "
			  "list IPv6 interfaces; %m");
		close(ifaces->sock);
		ifaces->sock = -1;
		fclose(ifaces->fp);
		ifaces->fp = NULL;
		return 0;
	}
#endif

	return 1;
}

/*
 * Read our IPv4 interfaces from /proc/net/dev.
 *
 * The file looks something like this:
 *
 * Inter-|   Receive ...
 *  face |bytes    packets errs drop fifo frame ...
 *     lo: 1580562    4207    0    0    0     0 ...
 *   eth0:       0       0    0    0    0     0 ...
 *   eth1:1801552440   37895    0   14    0     ...
 *
 * We only care about the interface name, which is at the start of 
 * each line.
 *
 * We use an ioctl() to get the address and flags for each interface.
 */
static int
next_iface4(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
	char buf[256];
	int len;
	char *p;
	char *name;
	struct ifreq tmp;

	/*
	 * Loop exits when we find an interface that has an address, or 
	 * when we run out of interfaces.
	 */
	for (;;) {
		do {
			/*
	 		 *  Read the next line in the file.
	 		 */
			if (fgets(buf, sizeof(buf), ifaces->fp) == NULL) {
				if (ferror(ifaces->fp)) {
					*err = 1;
					log_error("Error reading interface "
					  	"information");
				} else {
					*err = 0;
				}
				return 0;
			}

			/*
	 		 * Make sure the line is a nice, 
			 * newline-terminated line.
	 		 */
			len = strlen(buf);
			if ((len <= 0) || (buf[len-1] != '\n')) { 
				log_error("Bad line reading interface "
					  "information");
				*err = 1;
				return 0;
			}

			/*
	 		 * Figure out our name.
	 		 */
			p = strrchr(buf, ':');
			if (p == NULL) {
				log_error("Bad line reading interface "
					  "information (no colon)");
				*err = 1;
				return 0;
			}
			*p = '\0';
			name = buf;
			while (isspace(*name)) {
				name++;
			}

			/* 
		 	 * Copy our name into our interface structure.
		 	 */
			len = p - name;
			if (len >= sizeof(info->name)) {
				*err = 1;
				log_error("Interface name '%s' too long", name);
				return 0;
			}
			strcpy(info->name, name);

#ifdef ALIAS_NAMED_PERMUTED
			/* interface aliases look like "eth0:1" or "wlan1:3" */
			s = strchr(info->name, ':');
			if (s != NULL) {
				*s = '\0';
			}
#endif

#ifdef SKIP_DUMMY_INTERFACES
		} while (strncmp(info->name, "dummy", 5) == 0);
#else
		} while (0);
#endif

		memset(&tmp, 0, sizeof(tmp));
		strcpy(tmp.ifr_name, name);
		if (ioctl(ifaces->sock, SIOCGIFADDR, &tmp) < 0) {
			if (errno == EADDRNOTAVAIL) {
				continue;
			}
			log_error("Error getting interface address "
				  "for '%s'; %m", name);
			*err = 1;
			return 0;
		}
		memcpy(&info->addr, &tmp.ifr_addr, sizeof(tmp.ifr_addr));

		memset(&tmp, 0, sizeof(tmp));
		strcpy(tmp.ifr_name, name);
		if (ioctl(ifaces->sock, SIOCGIFFLAGS, &tmp) < 0) {
			log_error("Error getting interface flags for '%s'; %m", 
			  	name);
			*err = 1;
			return 0;
		}
		info->flags = tmp.ifr_flags;

		*err = 0;
		return 1;
	}
}

#ifdef DHCPv6
/*
 * Read our IPv6 interfaces from /proc/net/if_inet6.
 *
 * The file looks something like this:
 *
 * fe80000000000000025056fffec00008 05 40 20 80   vmnet8
 * 00000000000000000000000000000001 01 80 10 80       lo
 * fe80000000000000025056fffec00001 06 40 20 80   vmnet1
 * 200108881936000202166ffffe497d9b 03 40 00 00     eth1
 * fe8000000000000002166ffffe497d9b 03 40 20 80     eth1
 *
 * We get IPv6 address from the start, the interface name from the end, 
 * and ioctl() to get flags.
 */
static int
next_iface6(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
	char buf[256];
	int len;
	char *p;
	char *name;
	int i;
	struct sockaddr_in6 addr;
	struct ifreq tmp;

	do {
		/*
		 *  Read the next line in the file.
		 */
		if (fgets(buf, sizeof(buf), ifaces->fp6) == NULL) {
			if (ferror(ifaces->fp6)) {
				*err = 1;
				log_error("Error reading IPv6 "
					  "interface information");
			} else {
				*err = 0;
			}
			return 0;
		}

		/*
		 * Make sure the line is a nice, newline-terminated line.
		 */
		len = strlen(buf);
		if ((len <= 0) || (buf[len-1] != '\n')) { 
			log_error("Bad line reading IPv6 "
				  "interface information");
			*err = 1;
			return 0;
		}

		/*
 		 * Figure out our name.
 		 */
		buf[--len] = '\0';
		p = strrchr(buf, ' ');
		if (p == NULL) {
			log_error("Bad line reading IPv6 interface "
			          "information (no space)");
			*err = 1;
			return 0;
		}
		name = p+1;

		/* 
 		 * Copy our name into our interface structure.
 		 */
		len = strlen(name);
		if (len >= sizeof(info->name)) {
			*err = 1;
			log_error("IPv6 interface name '%s' too long", name);
			return 0;
		}
		strcpy(info->name, name);

#ifdef SKIP_DUMMY_INTERFACES
	} while (strncmp(info->name, "dummy", 5) == 0);
#else
	} while (0);
#endif

	/*
	 * Double-check we start with the IPv6 address.
	 */
	for (i=0; i<32; i++) {
		if (!isxdigit(buf[i]) || isupper(buf[i])) {
			*err = 1;
			log_error("Bad line reading IPv6 interface address "
				  "for '%s'", name);
			return 0;
		}
	}

	/* 
	 * Load our socket structure.
	 */
	memset(&addr, 0, sizeof(addr));
	addr.sin6_family = AF_INET6;
	for (i=0; i<16; i++) {
		unsigned char byte;
                static const char hex[] = "0123456789abcdef";
                byte = ((index(hex, buf[i * 2]) - hex) << 4) |
			(index(hex, buf[i * 2 + 1]) - hex);
		addr.sin6_addr.s6_addr[i] = byte;
	}
	memcpy(&info->addr, &addr, sizeof(addr));

	/*
	 * Get our flags.
	 */
	memset(&tmp, 0, sizeof(tmp));
	strcpy(tmp.ifr_name, name);
	if (ioctl(ifaces->sock, SIOCGIFFLAGS, &tmp) < 0) {
		log_error("Error getting interface flags for '%s'; %m", name);
		*err = 1;
		return 0;
	}
	info->flags = tmp.ifr_flags;

	*err = 0;
	return 1;
}
#endif /* DHCPv6 */

/*
 * Retrieve the next interface.
 *
 * Returns information in the info structure. 
 * Sets err to 1 if there is an error, otherwise 0.
 */
int
next_iface(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
	if (next_iface4(info, err, ifaces)) {
		return 1;
	}
#ifdef DHCPv6
	if (!(*err)) {
		return next_iface6(info, err, ifaces);
	}
#endif
	return 0;
}

/*
 * End scan of interfaces.
 */
void
end_iface_scan(struct iface_conf_list *ifaces) {
	fclose(ifaces->fp);
	ifaces->fp = NULL;
	close(ifaces->sock);
	ifaces->sock = -1;
#ifdef DHCPv6
	fclose(ifaces->fp6);
	ifaces->fp6 = NULL;
#endif
}
#else

/* 
 * BSD support
 * -----------
 *
 * FreeBSD, NetBSD, OpenBSD, and OS X all have the getifaddrs() 
 * function.
 *
 * The getifaddrs() man page describes the use.
 */

#include <ifaddrs.h>

/* 
 * Structure holding state about the scan.
 */
struct iface_conf_list {
	struct ifaddrs *head;	/* beginning of the list */
	struct ifaddrs *next;	/* current position in the list */
};

/* 
 * Structure used to return information about a specific interface.
 */
struct iface_info {
	char name[IFNAMSIZ];		/* name of the interface, e.g. "bge0" */
	struct sockaddr_storage addr;	/* address information */
	isc_uint64_t flags;		/* interface flags, e.g. IFF_LOOPBACK */
};

/* 
 * Start a scan of interfaces.
 *
 * The iface_conf_list structure maintains state for this process.
 */
int 
begin_iface_scan(struct iface_conf_list *ifaces) {
	if (getifaddrs(&ifaces->head) != 0) {
		log_error("Error getting interfaces; %m");
		return 0;
	}
	ifaces->next = ifaces->head;
	return 1;
}

/*
 * Retrieve the next interface.
 *
 * Returns information in the info structure. 
 * Sets err to 1 if there is an error, otherwise 0.
 */
int
next_iface(struct iface_info *info, int *err, struct iface_conf_list *ifaces) {
	if (ifaces->next == NULL) {
		*err = 0;
		return 0;
	}
	if (strlen(ifaces->next->ifa_name) >= sizeof(info->name)) {
		log_error("Interface name '%s' too long", 
			  ifaces->next->ifa_name);
		*err = 1;
		return 0;
	}
	strcpy(info->name, ifaces->next->ifa_name);
	memcpy(&info->addr, ifaces->next->ifa_addr, 
	       ifaces->next->ifa_addr->sa_len);
	info->flags = ifaces->next->ifa_flags;
	ifaces->next = ifaces->next->ifa_next;
	*err = 0;
	return 1;
}

/*
 * End scan of interfaces.
 */
void
end_iface_scan(struct iface_conf_list *ifaces) {
	freeifaddrs(ifaces->head);
	ifaces->head = NULL;
	ifaces->next = NULL;
}
#endif 

/* XXX: perhaps create drealloc() rather than do it manually */
void
add_ipv4_addr_to_interface(struct interface_info *iface, 
			   const struct in_addr *addr) {
	/*
	 * We don't expect a lot of addresses per IPv4 interface, so
	 * we use 4, as our "chunk size" for collecting addresses.
	 */
	if (iface->addresses == NULL) {
		iface->addresses = dmalloc(4 * sizeof(struct in_addr), MDL);
		if (iface->addresses == NULL) {
			log_fatal("Out of memory saving IPv4 address "
			          "on interface.");
		}
		iface->address_count = 0;
		iface->address_max = 4;
	} else if (iface->address_count >= iface->address_max) {
		struct in_addr *tmp;
		int new_max;

		new_max = iface->address_max + 4;
		tmp = dmalloc(new_max * sizeof(struct in_addr), MDL);
		if (tmp == NULL) {
			log_fatal("Out of memory saving IPv4 address "
			          "on interface.");
		}
		memcpy(tmp, 
		       iface->addresses, 
		       iface->address_max * sizeof(struct in_addr));
		dfree(iface->addresses, MDL);
		iface->addresses = tmp;
		iface->address_max = new_max;
	}
	iface->addresses[iface->address_count++] = *addr;
}

#ifdef DHCPv6
/* XXX: perhaps create drealloc() rather than do it manually */
void
add_ipv6_addr_to_interface(struct interface_info *iface, 
			   const struct in6_addr *addr) {
	/*
	 * Each IPv6 interface will have at least two IPv6 addresses,
	 * and likely quite a few more. So we use 8, as our "chunk size" for
	 * collecting addresses.
	 */
	if (iface->v6addresses == NULL) {
		iface->v6addresses = dmalloc(8 * sizeof(struct in6_addr), MDL);
		if (iface->v6addresses == NULL) {
			log_fatal("Out of memory saving IPv6 address "
				  "on interface.");
		}
		iface->v6address_count = 0;
		iface->v6address_max = 8;
	} else if (iface->v6address_count >= iface->v6address_max) {
		struct in6_addr *tmp;
		int new_max;

		new_max = iface->v6address_max + 8;
		tmp = dmalloc(new_max * sizeof(struct in6_addr), MDL);
		if (tmp == NULL) {
			log_fatal("Out of memory saving IPv6 address "
				  "on interface.");
		}
		memcpy(tmp, 
		       iface->v6addresses, 
		       iface->v6address_max * sizeof(struct in6_addr));
		dfree(iface->v6addresses, MDL);
		iface->v6addresses = tmp;
		iface->v6address_max = new_max;
	}
	iface->v6addresses[iface->v6address_count++] = *addr;
}
#endif /* DHCPv6 */

/* Use the SIOCGIFCONF ioctl to get a list of all the attached interfaces.
   For each interface that's of type INET and not the loopback interface,
   register that interface with the network I/O software, figure out what
   subnet it's on, and add it to the list of interfaces. */

void 
discover_interfaces(int state) {
	struct iface_conf_list ifaces;
	struct iface_info info;
	int err;

	struct interface_info *tmp;
	struct interface_info *last, *next;

#ifdef DHCPv6
        char abuf[sizeof("ffff:ffff:ffff:ffff:ffff:ffff:255.255.255.255")];
#endif /* DHCPv6 */


	struct subnet *subnet;
	int ir;
	isc_result_t status;
	int wifcount = 0;

	static int setup_fallback = 0;

	if (!begin_iface_scan(&ifaces)) {
		log_fatal("Can't get list of interfaces.");
	}

	/* If we already have a list of interfaces, and we're running as
	   a DHCP server, the interfaces were requested. */
	if (interfaces && (state == DISCOVER_SERVER ||
			   state == DISCOVER_RELAY ||
			   state == DISCOVER_REQUESTED))
		ir = 0;
	else if (state == DISCOVER_UNCONFIGURED)
		ir = INTERFACE_REQUESTED | INTERFACE_AUTOMATIC;
	else
		ir = INTERFACE_REQUESTED;

	/* Cycle through the list of interfaces looking for IP addresses. */
	while (next_iface(&info, &err, &ifaces)) {

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

		/* Skip non broadcast interfaces (plus loopback and
		   point-to-point in case an OS incorrectly marks them
		   as broadcast). Also skip down interfaces unless we're
		   trying to get a list of configurable interfaces. */
		if (((!(info.flags & IFF_BROADCAST) ||
		      info.flags & IFF_LOOPBACK ||
		      info.flags & IFF_POINTOPOINT) && !tmp) ||
		    (!(info.flags & IFF_UP) &&
		     state != DISCOVER_UNCONFIGURED))
			continue;
		
		/* If there isn't already an interface by this name,
		   allocate one. */
		if (tmp == NULL) {
			status = interface_allocate(&tmp, MDL);
			if (status != ISC_R_SUCCESS) {
				log_fatal("Error allocating interface %s: %s",
					  info.name, isc_result_totext(status));
			}
			strcpy(tmp->name, info.name);
			interface_snorf(tmp, ir);
			interface_dereference(&tmp, MDL);
			tmp = interfaces; /* XXX */
		}

		if (dhcp_interface_discovery_hook) {
			(*dhcp_interface_discovery_hook)(tmp);
		}

		if ((info.addr.ss_family == AF_INET) && 
		    (local_family == AF_INET)) {
			struct sockaddr_in *a = (struct sockaddr_in*)&info.addr;
			struct iaddr addr;

			/* We don't want the loopback interface. */
			if (a->sin_addr.s_addr == htonl(INADDR_LOOPBACK) &&
			    ((tmp->flags & INTERFACE_AUTOMATIC) &&
			     state == DISCOVER_SERVER))
				continue;

			/* If the only address we have is 0.0.0.0, we
			   shouldn't consider the interface configured. */
			if (a->sin_addr.s_addr != htonl(INADDR_ANY))
				tmp->configured = 1;

			add_ipv4_addr_to_interface(tmp, &a->sin_addr);

			/* invoke the setup hook */
			addr.len = 4;
			memcpy(addr.iabuf, &a->sin_addr.s_addr, addr.len);
			if (dhcp_interface_setup_hook) {
				(*dhcp_interface_setup_hook)(tmp, &addr);
			}
		}
#ifdef DHCPv6
		else if ((info.addr.ss_family == AF_INET6) && 
			 (local_family == AF_INET6)) {
			struct sockaddr_in6 *a = 
					(struct sockaddr_in6*)&info.addr;
			struct iaddr addr;

			/* We don't want the loopback interface. */
			if (IN6_IS_ADDR_LOOPBACK(&a->sin6_addr) && 
			    ((tmp->flags & INTERFACE_AUTOMATIC) &&
			     state == DISCOVER_SERVER))
			    continue;

			/* If the only address we have is 0.0.0.0, we
			   shouldn't consider the interface configured. */
			if (IN6_IS_ADDR_UNSPECIFIED(&a->sin6_addr))
				tmp->configured = 1;

			add_ipv6_addr_to_interface(tmp, &a->sin6_addr);

			/* invoke the setup hook */
			addr.len = 16;
			memcpy(addr.iabuf, &a->sin6_addr, addr.len);
			if (dhcp_interface_setup_hook) {
				(*dhcp_interface_setup_hook)(tmp, &addr);
			}
		}
#endif /* DHCPv6 */
	}

	if (err) {
		log_fatal("Error getting interface information.");
	}

	end_iface_scan(&ifaces);


	/* Mock-up an 'ifp' structure which is no longer used in the
	 * new interface-sensing code, but is used in higher layers
	 * (for example to sense fallback interfaces).
	 */
	for (tmp = interfaces ; tmp != NULL ; tmp = tmp->next) {
		if (tmp->ifp == NULL) {
			struct ifreq *tif;

			tif = (struct ifreq *)dmalloc(sizeof(struct ifreq),
						      MDL);
			if (tif == NULL)
				log_fatal("no space for ifp mockup.");
			strcpy(tif->ifr_name, tmp->name);
			tmp->ifp = tif;
		}
	}


	/* 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) {
		return;
	}

	/* Weed out the interfaces that did not have IP addresses. */
	tmp = last = next = NULL;
	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);

#ifdef DHCPv6
		if (!(tmp->flags & INTERFACE_REQUESTED)) {
#else
		if (!tmp -> ifp || !(tmp -> flags & INTERFACE_REQUESTED)) {
#endif /* DHCPv6 */
			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;

		/* We must have a subnet declaration for each interface. */
		if (!tmp->shared_network && (state == DISCOVER_SERVER)) {
			log_error("%s", "");
			if (local_family == AF_INET) {
				log_error("No subnet declaration for %s (%s).",
					  tmp->name, 
					  (tmp->addresses == NULL) ?
					   "no IPv4 addresses" :
					   inet_ntoa(tmp->addresses[0]));
#ifdef DHCPv6
			} else {
				if (tmp->v6addresses != NULL) {
					inet_ntop(AF_INET6, 
						  &tmp->v6addresses[0],
						  abuf,
						  sizeof(abuf));
				} else {
					strcpy(abuf, "no IPv6 addresses");
				}
				log_error("No subnet6 declaration for %s (%s).",
					  tmp->name,
					  abuf);
#endif /* DHCPv6 */
			}
			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",
#ifdef DHCPv6
				           (local_family != AF_INET) ?
					   "a subnet6 declaration" :
#endif
					   "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 %s",
#ifdef DHCPv6
				           (local_family != AF_INET) ?
					   "subnet6 declaration for this" :
#endif
					   "subnet 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) {
			/* Set the interface address for this subnet
			   to the first address we found. */
		     	if (subnet->interface_address.len == 0) {
				if (tmp->address_count > 0) {
					subnet->interface_address.len = 4;
					memcpy(subnet->interface_address.iabuf,
					       &tmp->addresses[0].s_addr, 4);
				} else if (tmp->v6address_count > 0) {
					subnet->interface_address.len = 16;
					memcpy(subnet->interface_address.iabuf,
					       &tmp->v6addresses[0].s6_addr, 
					       16);
				} else {
					/* XXX: should be one */
					log_error("%s missing an interface "
						  "address", tmp->name);
					continue;
				}
			}
		}

		/* 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 (local_family == AF_INET) {
			if_register_receive(tmp);
			if_register_send(tmp);
#ifdef DHCPv6
		} else {
			if ((state == DISCOVER_SERVER) ||
			    (state == DISCOVER_RELAY)) {
				if_register6(tmp, 1);
			} else {
				if_register6(tmp, 0);
			}
#endif /* DHCPv6 */
		}

		interface_stash (tmp);
		wifcount++;
#if defined (F_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;
#ifdef DHCPv6 
		if (local_family == AF_INET6) {
			status = omapi_register_io_object((omapi_object_t *)tmp,
							  if_readsocket, 
							  0, got_one_v6, 0, 0);
		} else {
#else
		{
#endif /* DHCPv6 */
			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));

#if defined(DHCPv6)
		/* Only register the first interface for V6, since they all
		 * use the same socket.  XXX: This has some messy side
		 * effects if we start dynamically adding and removing
		 * interfaces, but we're well beyond that point in terms of
		 * mess.
		 */
		if (local_family == AF_INET6)
			break;
#endif
	}

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

	if ((local_family == AF_INET) && !setup_fallback) {
		setup_fallback = 1;
		maybe_setup_fallback();
	}

#if defined (F_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 /* F_SETFD */
}

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;
	}
	if (result == 0)
		return ISC_R_UNEXPECTED;

	/* If we didn't at least get the fixed portion of the BOOTP
	   packet, drop the packet.  We're allowing packets with no
	   sname or filename, because we're aware of at least one
	   client that sends such packets, but this definitely falls
	   into the category of being forgiving. */
	if (result < DHCP_FIXED_NON_UDP - DHCP_SNAME_LEN - DHCP_FILE_LEN)
		return ISC_R_UNEXPECTED;

	if (bootp_packet_handler) {
		ifrom.len = 4;
		memcpy (ifrom.iabuf, &from.sin_addr, ifrom.len);

		(*bootp_packet_handler) (ip, &u.packet, (unsigned)result,
					 from.sin_port, ifrom, &hfrom);
	}

	/* If there is buffered data, read again.    This is for, e.g.,
	   bpf, which may return two packets at once. */
	if (ip -> rbuf_offset != ip -> rbuf_len)
		goto again;
	return ISC_R_SUCCESS;
}

#ifdef DHCPv6
isc_result_t
got_one_v6(omapi_object_t *h) {
	struct sockaddr_in6 from;
	struct in6_addr to;
	struct iaddr ifrom;
	int result;
	char buf[65536];	/* maximum size for a UDP packet is 65536 */
	struct interface_info *ip;
	int is_unicast;
	unsigned int if_idx = 0;

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

	result = receive_packet6(ip, (unsigned char *)buf, sizeof(buf),
				 &from, &to, &if_idx);
	if (result < 0) {
		log_error("receive_packet6() failed on %s: %m", ip->name);
		return ISC_R_UNEXPECTED;
	}

	/* 0 is 'any' interface. */
	if (if_idx == 0)
		return ISC_R_NOTFOUND;

	if (dhcpv6_packet_handler != NULL) {
		/*
		 * If a packet is not multicast, we assume it is unicast.
		 */
		if (IN6_IS_ADDR_MULTICAST(&to)) { 
			is_unicast = ISC_FALSE;
		} else {
			is_unicast = ISC_TRUE;
		}

		ifrom.len = 16;
		memcpy(ifrom.iabuf, &from.sin6_addr, ifrom.len);

		/* Seek forward to find the matching source interface. */
		while ((ip != NULL) && (if_nametoindex(ip->name) != if_idx))
			ip = ip->next;

		if (ip == NULL)
			return ISC_R_NOTFOUND;

		(*dhcpv6_packet_handler)(ip, buf, 
					 result, from.sin6_port, 
					 &ifrom, is_unicast);
	}

	return ISC_R_SUCCESS;
}
#endif /* DHCPv6 */

isc_result_t dhcp_interface_set_value  (omapi_object_t *h,
					omapi_object_t *id,
					omapi_data_string_t *name,
					omapi_typed_data_t *value)
{
	struct interface_info *interface;
	isc_result_t status;

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

	if (!omapi_ds_strcmp (name, "name")) {
		if ((value -> type == omapi_datatype_data ||
		     value -> type == omapi_datatype_string) &&
		    value -> u.buffer.len < sizeof interface -> name) {
			memcpy (interface -> name,
				value -> u.buffer.value,
				value -> u.buffer.len);
			interface -> name [value -> u.buffer.len] = 0;
		} else
			return ISC_R_INVALIDARG;
		return ISC_R_SUCCESS;
	}

	/* Try to find some inner object that can take the value. */
	if (h -> inner && h -> inner -> type -> set_value) {
		status = ((*(h -> inner -> type -> set_value))
			  (h -> inner, id, name, value));
		if (status == ISC_R_SUCCESS || status == ISC_R_UNCHANGED)
			return status;
	}
			  
	return ISC_R_NOTFOUND;
}


isc_result_t dhcp_interface_get_value (omapi_object_t *h,
				       omapi_object_t *id,
				       omapi_data_string_t *name,
				       omapi_value_t **value)
{
	return ISC_R_NOTIMPLEMENTED;
}

isc_result_t dhcp_interface_destroy (omapi_object_t *h,
					 const char *file, int line)
{
	struct interface_info *interface;

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

	if (interface -> ifp) {
		dfree (interface -> ifp, file, line);
		interface -> ifp = 0;
	}
	if (interface -> next)
		interface_dereference (&interface -> next, file, line);
	if (interface -> rbuf) {
		dfree (interface -> rbuf, file, line);
		interface -> rbuf = (unsigned char *)0;
	}
	if (interface -> client)
		interface -> client = (struct client_state *)0;

	if (interface -> shared_network)
		omapi_object_dereference ((omapi_object_t **)
					  &interface -> shared_network, MDL);

	return ISC_R_SUCCESS;
}

isc_result_t dhcp_interface_signal_handler (omapi_object_t *h,
					    const char *name, va_list ap)
{
	struct interface_info *ip, *interface;
	isc_result_t status;

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

	/* If it's an update signal, see if the interface is dead right
	   now, or isn't known at all, and if that's the case, revive it. */
	if (!strcmp (name, "update")) {
		for (ip = dummy_interfaces; ip; ip = ip -> next)
			if (ip == interface)
				break;
		if (ip && dhcp_interface_startup_hook)
			return (*dhcp_interface_startup_hook) (ip);

		for (ip = interfaces; ip; ip = ip -> next)
			if (ip == interface)
				break;
		if (!ip && dhcp_interface_startup_hook)
			return (*dhcp_interface_startup_hook) (ip);
	}

	/* Try to find some inner object that can take the value. */
	if (h -> inner && h -> inner -> type -> get_value) {
		status = ((*(h -> inner -> type -> signal_handler))
			  (h -> inner, name, ap));
		if (status == ISC_R_SUCCESS)
			return status;
	}
	return ISC_R_NOTFOUND;
}

isc_result_t dhcp_interface_stuff_values (omapi_object_t *c,
					  omapi_object_t *id,
					  omapi_object_t *h)
{
	struct interface_info *interface;
	isc_result_t status;

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

	/* Write out all the values. */

	status = omapi_connection_put_name (c, "state");
	if (status != ISC_R_SUCCESS)
		return status;
	if ((interface->flags & INTERFACE_REQUESTED) != 0)
	    status = omapi_connection_put_string (c, "up");
	else
	    status = omapi_connection_put_string (c, "down");
	if (status != ISC_R_SUCCESS)
		return status;

	/* Write out the inner object, if any. */
	if (h -> inner && h -> inner -> type -> stuff_values) {
		status = ((*(h -> inner -> type -> stuff_values))
			  (c, id, h -> inner));
		if (status == ISC_R_SUCCESS)
			return status;
	}

	return ISC_R_SUCCESS;
}

isc_result_t dhcp_interface_lookup (omapi_object_t **ip,
				    omapi_object_t *id,
				    omapi_object_t *ref)
{
	omapi_value_t *tv = (omapi_value_t *)0;
	isc_result_t status;
	struct interface_info *interface;

	if (!ref)
		return ISC_R_NOKEYS;

	/* First see if we were sent a handle. */
	status = omapi_get_value_str (ref, id, "handle", &tv);
	if (status == ISC_R_SUCCESS) {
		status = omapi_handle_td_lookup (ip, tv -> value);

		omapi_value_dereference (&tv, MDL);
		if (status != ISC_R_SUCCESS)
			return status;

		/* Don't return the object if the type is wrong. */
		if ((*ip) -> type != dhcp_type_interface) {
			omapi_object_dereference (ip, MDL);
			return ISC_R_INVALIDARG;
		}
	}

	/* Now look for an interface name. */
	status = omapi_get_value_str (ref, id, "name", &tv);
	if (status == ISC_R_SUCCESS) {
		char *s;
		unsigned len;
		for (interface = interfaces; interface;
		     interface = interface -> next) {
		    s = memchr (interface -> name, 0, IFNAMSIZ);
		    if (s)
			    len = s - &interface -> name [0];
		    else
			    len = IFNAMSIZ;
		    if ((tv -> value -> u.buffer.len == len &&
			 !memcmp (interface -> name,
				  (char *)tv -> value -> u.buffer.value,
				  len)))
			    break;
		}
		if (!interface) {
		    for (interface = dummy_interfaces;
			 interface; interface = interface -> next) {
			    s = memchr (interface -> name, 0, IFNAMSIZ);
			    if (s)
				    len = s - &interface -> name [0];
			    else
				    len = IFNAMSIZ;
			    if ((tv -> value -> u.buffer.len == len &&
				 !memcmp (interface -> name,
					  (char *)
					  tv -> value -> u.buffer.value,
					  len)))
				    break;
		    }
		}

		omapi_value_dereference (&tv, MDL);
		if (*ip && *ip != (omapi_object_t *)interface) {
			omapi_object_dereference (ip, MDL);
			return ISC_R_KEYCONFLICT;
		} else if (!interface) {
			if (*ip)
				omapi_object_dereference (ip, MDL);
			return ISC_R_NOTFOUND;
		} else if (!*ip)
			omapi_object_reference (ip,
						(omapi_object_t *)interface,
						MDL);
	}

	/* If we get to here without finding an interface, no valid key was
	   specified. */
	if (!*ip)
		return ISC_R_NOKEYS;
	return ISC_R_SUCCESS;
}

/* actually just go discover the interface */
isc_result_t dhcp_interface_create (omapi_object_t **lp,
				    omapi_object_t *id)
{
 	struct interface_info *hp;
	isc_result_t status;
	
	hp = (struct interface_info *)0;
	status = interface_allocate (&hp, MDL);
 	if (status != ISC_R_SUCCESS)
		return status;
 	hp -> flags = INTERFACE_REQUESTED;
	status = interface_reference ((struct interface_info **)lp, hp, MDL);
	interface_dereference (&hp, MDL);
	return status;
}

isc_result_t dhcp_interface_remove (omapi_object_t *lp,
				    omapi_object_t *id)
{
 	struct interface_info *interface, *ip, *last;

	interface = (struct interface_info *)lp;

	/* remove from interfaces */
	last = 0;
	for (ip = interfaces; ip; ip = ip -> next) {
		if (ip == interface) {
			if (last) {
				interface_dereference (&last -> next, MDL);
				if (ip -> next)
					interface_reference (&last -> next,
							     ip -> next, MDL);
			} else {
				interface_dereference (&interfaces, MDL);
				if (ip -> next)
					interface_reference (&interfaces,
							     ip -> next, MDL);
			}
			if (ip -> next)
				interface_dereference (&ip -> next, MDL);
			break;
		}
		last = ip;
	}
	if (!ip)
		return ISC_R_NOTFOUND;

	/* add the interface to the dummy_interface list */
	if (dummy_interfaces) {
		interface_reference (&interface -> next,
				     dummy_interfaces, MDL);
		interface_dereference (&dummy_interfaces, MDL);
	}
	interface_reference (&dummy_interfaces, interface, MDL);

	/* do a DHCPRELEASE */
	if (dhcp_interface_shutdown_hook)
		(*dhcp_interface_shutdown_hook) (interface);

	/* remove the io object */
	omapi_unregister_io_object ((omapi_object_t *)interface);

	if (local_family == AF_INET) {
		if_deregister_send(interface);
		if_deregister_receive(interface);
#ifdef DHCPv6
	} else {
		if_deregister6(interface);
#endif /* DHCPv6 */
	}

	return ISC_R_SUCCESS;
}

void interface_stash (struct interface_info *tptr)
{
	struct interface_info **vec;
	int delta;

	/* If the registerer didn't assign an index, assign one now. */
	if (tptr -> index == -1) {
		tptr -> index = interface_count++;
		while (tptr -> index < interface_max &&
		       interface_vector [tptr -> index])
			tptr -> index = interface_count++;
	}

	if (interface_max <= tptr -> index) {
		delta = tptr -> index - interface_max + 10;
		vec = dmalloc ((interface_max + delta) *
			       sizeof (struct interface_info *), MDL);
		if (!vec)
			return;
		memset (&vec [interface_max], 0,
			(sizeof (struct interface_info *)) * delta);
		interface_max += delta;
		if (interface_vector) {
		    memcpy (vec, interface_vector,
			    (interface_count *
			     sizeof (struct interface_info *)));
		    dfree (interface_vector, MDL);
		}
		interface_vector = vec;
	}
	interface_reference (&interface_vector [tptr -> index], tptr, MDL);
	if (tptr -> index >= interface_count)
		interface_count = tptr -> index + 1;
#if defined (TRACING)
	trace_interface_register (interface_trace, tptr);
#endif
}

void interface_snorf (struct interface_info *tmp, int ir)
{
	tmp -> circuit_id = (u_int8_t *)tmp -> name;
	tmp -> circuit_id_len = strlen (tmp -> name);
	tmp -> remote_id = 0;
	tmp -> remote_id_len = 0;
	tmp -> flags = ir;
	if (interfaces) {
		interface_reference (&tmp -> next,
				     interfaces, MDL);
		interface_dereference (&interfaces, MDL);
	}
	interface_reference (&interfaces, tmp, MDL);
}