net.c - chromiumos/third_party/dhcpcd - Git at Google

 /*
  * dhcpcd - DHCP client daemon
  * Copyright (c) 2006-2013 Roy Marples <roy@marples.name>
  * All rights reserved

  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */

 #include <sys/param.h>
 #include <sys/types.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>

 #include <net/if.h>
 #include <net/if_arp.h>
 #include <netinet/in.h>
 #ifdef __FreeBSD__ /* Needed so that including netinet6/in6_var.h works */
 #  include <net/if_var.h>
 #endif
 #ifdef AF_LINK
 #  include <net/if_dl.h>
 #  include <net/if_types.h>
 #  include <netinet/in_var.h>
 #endif
 #ifdef AF_PACKET
 #  include <netpacket/packet.h>
 #endif
 #ifdef SIOCGIFMEDIA
 #  include <net/if_media.h>
 #endif

 #include <net/route.h>
 #ifdef __linux__
 #  include <asm/types.h> /* for systems with broken headers */
 #  include <linux/rtnetlink.h>
 #endif

 #include <ctype.h>
 #include <errno.h>
 #include <ifaddrs.h>
 #include <fnmatch.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <syslog.h>
 #include <unistd.h>

 #include "config.h"
 #include "common.h"
 #include "dhcp.h"
 #include "dhcp6.h"
 #include "if-options.h"
 #include "ipv6rs.h"
 #include "net.h"

 int socket_afnet = -1;

 static char hwaddr_buffer[(HWADDR_LEN * 3) + 1 + 1024];

 char *
 hwaddr_ntoa(const unsigned char *hwaddr, size_t hwlen)
 {
 	char *p = hwaddr_buffer;
 	size_t i;

 	for (i = 0; i < hwlen; i++) {
 		if (i > 0)
 			*p ++= ':';
 		p += snprintf(p, 3, "%.2x", hwaddr[i]);
 	}

 	*p ++= '\0';

 	return hwaddr_buffer;
 }

 size_t
 hwaddr_aton(unsigned char *buffer, const char *addr)
 {
 	char c[3];
 	const char *p = addr;
 	unsigned char *bp = buffer;
 	size_t len = 0;

 	c[2] = '\0';
 	while (*p) {
 		c[0] = *p++;
 		c[1] = *p++;
 		/* Ensure that digits are hex */
 		if (isxdigit((unsigned char)c[0]) == 0 ||
 		    isxdigit((unsigned char)c[1]) == 0)
 		{
 			errno = EINVAL;
 			return 0;
 		}
 		/* We should have at least two entries 00:01 */
 		if (len == 0 && *p == '\0') {
 			errno = EINVAL;
 			return 0;
 		}
 		/* Ensure that next data is EOL or a seperator with data */
 		if (!(*p == '\0' || (*p == ':' && *(p + 1) != '\0'))) {
 			errno = EINVAL;
 			return 0;
 		}
 		if (*p)
 			p++;
 		if (bp)
 			*bp++ = (unsigned char)strtol(c, NULL, 16);
 		len++;
 	}
 	return len;
 }

 void
 free_interface(struct interface *ifp)
 {

 	if (ifp == NULL)
 		return;
 	dhcp_free(ifp);
 	ipv6_free(ifp);
 	dhcp6_free(ifp);
 	ipv6rs_free(ifp);
 	free_options(ifp->options);
 	free(ifp);
 }

 int
 carrier_status(struct interface *iface)
 {
 	int ret;
 	struct ifreq ifr;
 #ifdef SIOCGIFMEDIA
 	struct ifmediareq ifmr;
 #endif
 #ifdef __linux__
 	char *p;
 #endif

 	memset(&ifr, 0, sizeof(ifr));
 	strlcpy(ifr.ifr_name, iface->name, sizeof(ifr.ifr_name));
 #ifdef __linux__
 	/* We can only test the real interface up */
 	if ((p = strchr(ifr.ifr_name, ':')))
 		*p = '\0';
 #endif

 	if (ioctl(socket_afnet, SIOCGIFFLAGS, &ifr) == -1)
 		return -1;
 	iface->flags = ifr.ifr_flags;

 	ret = LINK_UNKNOWN;
 #ifdef SIOCGIFMEDIA
 	memset(&ifmr, 0, sizeof(ifmr));
 	strlcpy(ifmr.ifm_name, iface->name, sizeof(ifmr.ifm_name));
 	if (ioctl(socket_afnet, SIOCGIFMEDIA, &ifmr) != -1 &&
 	    ifmr.ifm_status & IFM_AVALID)
 		ret = (ifmr.ifm_status & IFM_ACTIVE) ? LINK_UP : LINK_DOWN;
 #endif
 	if (ret == LINK_UNKNOWN)
 		ret = (ifr.ifr_flags & IFF_RUNNING) ? LINK_UP : LINK_DOWN;
 	return ret;
 }

 int
 up_interface(struct interface *iface)
 {
 	struct ifreq ifr;
 	int retval = -1;
 #ifdef __linux__
 	char *p;
 #endif

 	memset(&ifr, 0, sizeof(ifr));
 	strlcpy(ifr.ifr_name, iface->name, sizeof(ifr.ifr_name));
 #ifdef __linux__
 	/* We can only bring the real interface up */
 	if ((p = strchr(ifr.ifr_name, ':')))
 		*p = '\0';
 #endif
 	if (ioctl(socket_afnet, SIOCGIFFLAGS, &ifr) == 0) {
 		if ((ifr.ifr_flags & IFF_UP))
 			retval = 0;
 		else {
 			ifr.ifr_flags |= IFF_UP;
 			if (ioctl(socket_afnet, SIOCSIFFLAGS, &ifr) == 0)
 				retval = 0;
 		}
 		iface->flags = ifr.ifr_flags;
 	}
 	return retval;
 }

 struct if_head *
 discover_interfaces(int argc, char * const *argv)
 {
 	struct ifaddrs *ifaddrs, *ifa;
 	char *p;
 	int i, sdl_type;
 	struct if_head *ifs;
 	struct interface *ifp;
 #ifdef __linux__
 	char ifn[IF_NAMESIZE];
 #endif
 #ifdef INET6
 	const struct sockaddr_in6 *sin6;
 	int ifa_flags;
 #endif
 #ifdef AF_LINK
 	const struct sockaddr_dl *sdl;
 #ifdef IFLR_ACTIVE
 	struct if_laddrreq iflr;
 	int socket_aflink;

 	socket_aflink = socket(AF_LINK, SOCK_DGRAM, 0);
 	if (socket_aflink == -1)
 		return NULL;
 	memset(&iflr, 0, sizeof(iflr));
 #endif
 #elif AF_PACKET
 	const struct sockaddr_ll *sll;
 #endif

 	if (getifaddrs(&ifaddrs) == -1)
 		return NULL;

 	ifs = malloc(sizeof(*ifs));
 	if (ifs == NULL)
 		return NULL;
 	TAILQ_INIT(ifs);

 	for (ifa = ifaddrs; ifa; ifa = ifa->ifa_next) {
 		if (ifa->ifa_addr != NULL) {
 #ifdef AF_LINK
 			if (ifa->ifa_addr->sa_family != AF_LINK)
 				continue;
 #elif AF_PACKET
 			if (ifa->ifa_addr->sa_family != AF_PACKET)
 				continue;
 #endif
 		}

 		/* It's possible for an interface to have >1 AF_LINK.
 		 * For our purposes, we use the first one. */
 		TAILQ_FOREACH(ifp, ifs, next) {
 			if (strcmp(ifp->name, ifa->ifa_name) == 0)
 				break;
 		}
 		if (ifp)
 			continue;
 		if (argc > 0) {
 			for (i = 0; i < argc; i++) {
 #ifdef __linux__
 				/* Check the real interface name */
 				strlcpy(ifn, argv[i], sizeof(ifn));
 				p = strchr(ifn, ':');
 				if (p)
 					*p = '\0';
 				if (strcmp(ifn, ifa->ifa_name) == 0)
 					break;
 #else
 				if (strcmp(argv[i], ifa->ifa_name) == 0)
 					break;
 #endif
 			}
 			if (i == argc)
 				continue;
 			p = argv[i];
 		} else {
 			p = ifa->ifa_name;
 			/* -1 means we're discovering against a specific
 			 * interface, but we still need the below rules
 			 * to apply. */
 			if (argc == -1 && strcmp(argv[0], ifa->ifa_name) != 0)
 				continue;
 		}
 		for (i = 0; i < ifdc; i++)
 			if (!fnmatch(ifdv[i], p, 0))
 				break;
 		if (i < ifdc)
 			continue;
 		for (i = 0; i < ifac; i++)
 			if (!fnmatch(ifav[i], p, 0))
 				break;
 		if (ifac && i == ifac)
 			continue;

 		ifp = calloc(1, sizeof(*ifp));
 		if (ifp == NULL)
 			return NULL;
 		strlcpy(ifp->name, p, sizeof(ifp->name));
 		ifp->flags = ifa->ifa_flags;

 		/* Bring the interface up if not already */
 		if (!(ifp->flags & IFF_UP)
 #ifdef SIOCGIFMEDIA
 		    && carrier_status(ifp) != -1
 #endif
 		   )
 		{
 			if (up_interface(ifp) == 0)
 				options |= DHCPCD_WAITUP;
 			else
 				syslog(LOG_ERR, "%s: up_interface: %m",
 				    ifp->name);
 		}

 		sdl_type = 0;
 		/* Don't allow loopback unless explicit */
 		if (ifp->flags & IFF_LOOPBACK) {
 			if (argc == 0 && ifac == 0) {
 				free_interface(ifp);
 				continue;
 			}
 		} else if (ifa->ifa_addr != NULL) {
 #ifdef AF_LINK
 			sdl = (const struct sockaddr_dl *)(void *)ifa->ifa_addr;

 #ifdef IFLR_ACTIVE
 			/* We need to check for active address */
 			strlcpy(iflr.iflr_name, ifp->name,
 			    sizeof(iflr.iflr_name));
 			memcpy(&iflr.addr, ifa->ifa_addr,
 			    MIN(ifa->ifa_addr->sa_len, sizeof(iflr.addr)));
 			iflr.flags = IFLR_PREFIX;
 			iflr.prefixlen = sdl->sdl_alen * NBBY;
 			if (ioctl(socket_aflink, SIOCGLIFADDR, &iflr) == -1 ||
 			    !(iflr.flags & IFLR_ACTIVE))
 			{
 				free_interface(ifp);
 				continue;
 			}
 #endif

 			ifp->index = sdl->sdl_index;
 			sdl_type = sdl->sdl_type;
 			switch(sdl->sdl_type) {
 			case IFT_BRIDGE: /* FALLTHROUGH */
 			case IFT_L2VLAN: /* FALLTHOUGH */
 			case IFT_L3IPVLAN: /* FALLTHROUGH */
 			case IFT_ETHER:
 				ifp->family = ARPHRD_ETHER;
 				break;
 			case IFT_IEEE1394:
 				ifp->family = ARPHRD_IEEE1394;
 				break;
 #ifdef IFT_INFINIBAND
 			case IFT_INFINIBAND:
 				ifp->family = ARPHRD_INFINIBAND;
 				break;
 #endif
 			}
 			ifp->hwlen = sdl->sdl_alen;
 #ifndef CLLADDR
 #  define CLLADDR(s) ((const char *)((s)->sdl_data + (s)->sdl_nlen))
 #endif
 			memcpy(ifp->hwaddr, CLLADDR(sdl), ifp->hwlen);
 #elif AF_PACKET
 			sll = (const struct sockaddr_ll *)(void *)ifa->ifa_addr;
 			ifp->index = sll->sll_ifindex;
 			ifp->family = sdl_type = sll->sll_hatype;
 			ifp->hwlen = sll->sll_halen;
 			if (ifp->hwlen != 0)
 				memcpy(ifp->hwaddr, sll->sll_addr, ifp->hwlen);
 #endif
 		}
 #ifdef __linux__
 		/* PPP addresses on Linux don't have hardware addresses */
 		else
 			ifp->index = if_nametoindex(ifp->name);
 #endif

 		/* We only work on ethernet by default */
 		if (!(ifp->flags & IFF_POINTOPOINT) &&
 		    ifp->family != ARPHRD_ETHER)
 		{
 			if (argc == 0 && ifac == 0) {
 				free_interface(ifp);
 				continue;
 			}
 			switch (ifp->family) {
 			case ARPHRD_IEEE1394: /* FALLTHROUGH */
 			case ARPHRD_INFINIBAND:
 				/* We don't warn for supported families */
 				break;
 			default:
 				syslog(LOG_WARNING,
 				    "%s: unsupported interface type %.2x"
 				    ", falling back to ethernet",
 				    ifp->name, sdl_type);
 				ifp->family = ARPHRD_ETHER;
 				break;
 			}
 		}

 		/* Handle any platform init for the interface */
 		if (if_init(ifp) == -1) {
 			syslog(LOG_ERR, "%s: if_init: %m", p);
 			free_interface(ifp);
 			continue;
 		}

 		/* Ensure that the MTU is big enough for DHCP */
 		if (get_mtu(ifp->name) < MTU_MIN &&
 		    set_mtu(ifp->name, MTU_MIN) == -1)
 		{
 			syslog(LOG_ERR, "%s: set_mtu: %m", p);
 			free_interface(ifp);
 			continue;
 		}

 		/* We reserve the 100 range for virtual interfaces, if and when
 		 * we can work them out. */
 		ifp->metric = 200 + ifp->index;
 		if (getifssid(ifp->name, ifp->ssid) != -1) {
 			ifp->wireless = 1;
 			ifp->metric += 100;
 		}

 		TAILQ_INSERT_TAIL(ifs, ifp, next);
 	}

 #ifdef INET6
 	for (ifa = ifaddrs; ifa; ifa = ifa->ifa_next) {
 		if (ifa->ifa_addr != NULL &&
 		    ifa->ifa_addr->sa_family == AF_INET6)
 		{
 			sin6 = (const struct sockaddr_in6 *)
 			    (void *)ifa->ifa_addr;
 			ifa_flags = in6_addr_flags(ifa->ifa_name,
 			    &sin6->sin6_addr);
 			if (ifa_flags != -1)
 				ipv6_handleifa(RTM_NEWADDR, ifs,
 				    ifa->ifa_name,
 				    &sin6->sin6_addr, ifa_flags);
 		}
 	}
 #endif

 	freeifaddrs(ifaddrs);

 #ifdef IFLR_ACTIVE
 	close(socket_aflink);
 #endif

 	return ifs;
 }

 int
 do_mtu(const char *ifname, short int mtu)
 {
 	struct ifreq ifr;
 	int r;

 	memset(&ifr, 0, sizeof(ifr));
 	strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 	ifr.ifr_mtu = mtu;
 	r = ioctl(socket_afnet, mtu ? SIOCSIFMTU : SIOCGIFMTU, &ifr);
 	if (r == -1)
 		return -1;
 	return ifr.ifr_mtu;
 }
	/*
	* dhcpcd - DHCP client daemon
	* Copyright (c) 2006-2013 Roy Marples <roy@marples.name>
	* All rights reserved

	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	*/

	#include <sys/param.h>
	#include <sys/types.h>
	#include <sys/ioctl.h>
	#include <sys/socket.h>

	#include <net/if.h>
	#include <net/if_arp.h>
	#include <netinet/in.h>
	#ifdef __FreeBSD__ /* Needed so that including netinet6/in6_var.h works */
	# include <net/if_var.h>
	#endif
	#ifdef AF_LINK
	# include <net/if_dl.h>
	# include <net/if_types.h>
	# include <netinet/in_var.h>
	#endif
	#ifdef AF_PACKET
	# include <netpacket/packet.h>
	#endif
	#ifdef SIOCGIFMEDIA
	# include <net/if_media.h>
	#endif

	#include <net/route.h>
	#ifdef __linux__
	# include <asm/types.h> /* for systems with broken headers */
	# include <linux/rtnetlink.h>
	#endif

	#include <ctype.h>
	#include <errno.h>
	#include <ifaddrs.h>
	#include <fnmatch.h>
	#include <stddef.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <syslog.h>
	#include <unistd.h>

	#include "config.h"
	#include "common.h"
	#include "dhcp.h"
	#include "dhcp6.h"
	#include "if-options.h"
	#include "ipv6rs.h"
	#include "net.h"

	int socket_afnet = -1;

	static char hwaddr_buffer[(HWADDR_LEN * 3) + 1 + 1024];

	char *
	hwaddr_ntoa(const unsigned char *hwaddr, size_t hwlen)
	{
	char *p = hwaddr_buffer;
	size_t i;

	for (i = 0; i < hwlen; i++) {
	if (i > 0)
	*p ++= ':';
	p += snprintf(p, 3, "%.2x", hwaddr[i]);
	}

	*p ++= '\0';

	return hwaddr_buffer;
	}

	size_t
	hwaddr_aton(unsigned char buffer, const char addr)
	{
	char c[3];
	const char *p = addr;
	unsigned char *bp = buffer;
	size_t len = 0;

	c[2] = '\0';
	while (*p) {
	c[0] = *p++;
	c[1] = *p++;
	/* Ensure that digits are hex */
	if (isxdigit((unsigned char)c[0]) == 0 \|\|
	isxdigit((unsigned char)c[1]) == 0)
	{
	errno = EINVAL;
	return 0;
	}
	/* We should have at least two entries 00:01 */
	if (len == 0 && *p == '\0') {
	errno = EINVAL;
	return 0;
	}
	/* Ensure that next data is EOL or a seperator with data */
	if (!(p == '\0' \|\| (p == ':' && *(p + 1) != '\0'))) {
	errno = EINVAL;
	return 0;
	}
	if (*p)
	p++;
	if (bp)
	*bp++ = (unsigned char)strtol(c, NULL, 16);
	len++;
	}
	return len;
	}

	void
	free_interface(struct interface *ifp)
	{

	if (ifp == NULL)
	return;
	dhcp_free(ifp);
	ipv6_free(ifp);
	dhcp6_free(ifp);
	ipv6rs_free(ifp);
	free_options(ifp->options);
	free(ifp);
	}

	int
	carrier_status(struct interface *iface)
	{
	int ret;
	struct ifreq ifr;
	#ifdef SIOCGIFMEDIA
	struct ifmediareq ifmr;
	#endif
	#ifdef __linux__
	char *p;
	#endif

	memset(&ifr, 0, sizeof(ifr));
	strlcpy(ifr.ifr_name, iface->name, sizeof(ifr.ifr_name));
	#ifdef __linux__
	/* We can only test the real interface up */
	if ((p = strchr(ifr.ifr_name, ':')))
	*p = '\0';
	#endif

	if (ioctl(socket_afnet, SIOCGIFFLAGS, &ifr) == -1)
	return -1;
	iface->flags = ifr.ifr_flags;

	ret = LINK_UNKNOWN;
	#ifdef SIOCGIFMEDIA
	memset(&ifmr, 0, sizeof(ifmr));
	strlcpy(ifmr.ifm_name, iface->name, sizeof(ifmr.ifm_name));
	if (ioctl(socket_afnet, SIOCGIFMEDIA, &ifmr) != -1 &&
	ifmr.ifm_status & IFM_AVALID)
	ret = (ifmr.ifm_status & IFM_ACTIVE) ? LINK_UP : LINK_DOWN;
	#endif
	if (ret == LINK_UNKNOWN)
	ret = (ifr.ifr_flags & IFF_RUNNING) ? LINK_UP : LINK_DOWN;
	return ret;
	}

	int
	up_interface(struct interface *iface)
	{
	struct ifreq ifr;
	int retval = -1;
	#ifdef __linux__
	char *p;
	#endif

	memset(&ifr, 0, sizeof(ifr));
	strlcpy(ifr.ifr_name, iface->name, sizeof(ifr.ifr_name));
	#ifdef __linux__
	/* We can only bring the real interface up */
	if ((p = strchr(ifr.ifr_name, ':')))
	*p = '\0';
	#endif
	if (ioctl(socket_afnet, SIOCGIFFLAGS, &ifr) == 0) {
	if ((ifr.ifr_flags & IFF_UP))
	retval = 0;
	else {
	ifr.ifr_flags \|= IFF_UP;
	if (ioctl(socket_afnet, SIOCSIFFLAGS, &ifr) == 0)
	retval = 0;
	}
	iface->flags = ifr.ifr_flags;
	}
	return retval;
	}

	struct if_head *
	discover_interfaces(int argc, char * const *argv)
	{
	struct ifaddrs ifaddrs, ifa;
	char *p;
	int i, sdl_type;
	struct if_head *ifs;
	struct interface *ifp;
	#ifdef __linux__
	char ifn[IF_NAMESIZE];
	#endif
	#ifdef INET6
	const struct sockaddr_in6 *sin6;
	int ifa_flags;
	#endif
	#ifdef AF_LINK
	const struct sockaddr_dl *sdl;
	#ifdef IFLR_ACTIVE
	struct if_laddrreq iflr;
	int socket_aflink;

	socket_aflink = socket(AF_LINK, SOCK_DGRAM, 0);
	if (socket_aflink == -1)
	return NULL;
	memset(&iflr, 0, sizeof(iflr));
	#endif
	#elif AF_PACKET
	const struct sockaddr_ll *sll;
	#endif

	if (getifaddrs(&ifaddrs) == -1)
	return NULL;

	ifs = malloc(sizeof(*ifs));
	if (ifs == NULL)
	return NULL;
	TAILQ_INIT(ifs);

	for (ifa = ifaddrs; ifa; ifa = ifa->ifa_next) {
	if (ifa->ifa_addr != NULL) {
	#ifdef AF_LINK
	if (ifa->ifa_addr->sa_family != AF_LINK)
	continue;
	#elif AF_PACKET
	if (ifa->ifa_addr->sa_family != AF_PACKET)
	continue;
	#endif
	}

	/* It's possible for an interface to have >1 AF_LINK.
	* For our purposes, we use the first one. */
	TAILQ_FOREACH(ifp, ifs, next) {
	if (strcmp(ifp->name, ifa->ifa_name) == 0)
	break;
	}
	if (ifp)
	continue;
	if (argc > 0) {
	for (i = 0; i < argc; i++) {
	#ifdef __linux__
	/* Check the real interface name */
	strlcpy(ifn, argv[i], sizeof(ifn));
	p = strchr(ifn, ':');
	if (p)
	*p = '\0';
	if (strcmp(ifn, ifa->ifa_name) == 0)
	break;
	#else
	if (strcmp(argv[i], ifa->ifa_name) == 0)
	break;
	#endif
	}
	if (i == argc)
	continue;
	p = argv[i];
	} else {
	p = ifa->ifa_name;
	/* -1 means we're discovering against a specific
	* interface, but we still need the below rules
	* to apply. */
	if (argc == -1 && strcmp(argv[0], ifa->ifa_name) != 0)
	continue;
	}
	for (i = 0; i < ifdc; i++)
	if (!fnmatch(ifdv[i], p, 0))
	break;
	if (i < ifdc)
	continue;
	for (i = 0; i < ifac; i++)
	if (!fnmatch(ifav[i], p, 0))
	break;
	if (ifac && i == ifac)
	continue;

	ifp = calloc(1, sizeof(*ifp));
	if (ifp == NULL)
	return NULL;
	strlcpy(ifp->name, p, sizeof(ifp->name));
	ifp->flags = ifa->ifa_flags;

	/* Bring the interface up if not already */
	if (!(ifp->flags & IFF_UP)
	#ifdef SIOCGIFMEDIA
	&& carrier_status(ifp) != -1
	#endif
	)
	{
	if (up_interface(ifp) == 0)
	options \|= DHCPCD_WAITUP;
	else
	syslog(LOG_ERR, "%s: up_interface: %m",
	ifp->name);
	}

	sdl_type = 0;
	/* Don't allow loopback unless explicit */
	if (ifp->flags & IFF_LOOPBACK) {
	if (argc == 0 && ifac == 0) {
	free_interface(ifp);
	continue;
	}
	} else if (ifa->ifa_addr != NULL) {
	#ifdef AF_LINK
	sdl = (const struct sockaddr_dl )(void )ifa->ifa_addr;

	#ifdef IFLR_ACTIVE
	/* We need to check for active address */
	strlcpy(iflr.iflr_name, ifp->name,
	sizeof(iflr.iflr_name));
	memcpy(&iflr.addr, ifa->ifa_addr,
	MIN(ifa->ifa_addr->sa_len, sizeof(iflr.addr)));
	iflr.flags = IFLR_PREFIX;
	iflr.prefixlen = sdl->sdl_alen * NBBY;
	if (ioctl(socket_aflink, SIOCGLIFADDR, &iflr) == -1 \|\|
	!(iflr.flags & IFLR_ACTIVE))
	{
	free_interface(ifp);
	continue;
	}
	#endif

	ifp->index = sdl->sdl_index;
	sdl_type = sdl->sdl_type;
	switch(sdl->sdl_type) {
	case IFT_BRIDGE: /* FALLTHROUGH */
	case IFT_L2VLAN: /* FALLTHOUGH */
	case IFT_L3IPVLAN: /* FALLTHROUGH */
	case IFT_ETHER:
	ifp->family = ARPHRD_ETHER;
	break;
	case IFT_IEEE1394:
	ifp->family = ARPHRD_IEEE1394;
	break;
	#ifdef IFT_INFINIBAND
	case IFT_INFINIBAND:
	ifp->family = ARPHRD_INFINIBAND;
	break;
	#endif
	}
	ifp->hwlen = sdl->sdl_alen;
	#ifndef CLLADDR
	# define CLLADDR(s) ((const char *)((s)->sdl_data + (s)->sdl_nlen))
	#endif
	memcpy(ifp->hwaddr, CLLADDR(sdl), ifp->hwlen);
	#elif AF_PACKET
	sll = (const struct sockaddr_ll )(void )ifa->ifa_addr;
	ifp->index = sll->sll_ifindex;
	ifp->family = sdl_type = sll->sll_hatype;
	ifp->hwlen = sll->sll_halen;
	if (ifp->hwlen != 0)
	memcpy(ifp->hwaddr, sll->sll_addr, ifp->hwlen);
	#endif
	}
	#ifdef __linux__
	/* PPP addresses on Linux don't have hardware addresses */
	else
	ifp->index = if_nametoindex(ifp->name);
	#endif

	/* We only work on ethernet by default */
	if (!(ifp->flags & IFF_POINTOPOINT) &&
	ifp->family != ARPHRD_ETHER)
	{
	if (argc == 0 && ifac == 0) {
	free_interface(ifp);
	continue;
	}
	switch (ifp->family) {
	case ARPHRD_IEEE1394: /* FALLTHROUGH */
	case ARPHRD_INFINIBAND:
	/* We don't warn for supported families */
	break;
	default:
	syslog(LOG_WARNING,
	"%s: unsupported interface type %.2x"
	", falling back to ethernet",
	ifp->name, sdl_type);
	ifp->family = ARPHRD_ETHER;
	break;
	}
	}

	/* Handle any platform init for the interface */
	if (if_init(ifp) == -1) {
	syslog(LOG_ERR, "%s: if_init: %m", p);
	free_interface(ifp);
	continue;
	}

	/* Ensure that the MTU is big enough for DHCP */
	if (get_mtu(ifp->name) < MTU_MIN &&
	set_mtu(ifp->name, MTU_MIN) == -1)
	{
	syslog(LOG_ERR, "%s: set_mtu: %m", p);
	free_interface(ifp);
	continue;
	}

	/* We reserve the 100 range for virtual interfaces, if and when
	* we can work them out. */
	ifp->metric = 200 + ifp->index;
	if (getifssid(ifp->name, ifp->ssid) != -1) {
	ifp->wireless = 1;
	ifp->metric += 100;
	}

	TAILQ_INSERT_TAIL(ifs, ifp, next);
	}

	#ifdef INET6
	for (ifa = ifaddrs; ifa; ifa = ifa->ifa_next) {
	if (ifa->ifa_addr != NULL &&
	ifa->ifa_addr->sa_family == AF_INET6)
	{
	sin6 = (const struct sockaddr_in6 *)
	(void *)ifa->ifa_addr;
	ifa_flags = in6_addr_flags(ifa->ifa_name,
	&sin6->sin6_addr);
	if (ifa_flags != -1)
	ipv6_handleifa(RTM_NEWADDR, ifs,
	ifa->ifa_name,
	&sin6->sin6_addr, ifa_flags);
	}
	}
	#endif

	freeifaddrs(ifaddrs);

	#ifdef IFLR_ACTIVE
	close(socket_aflink);
	#endif

	return ifs;
	}

	int
	do_mtu(const char *ifname, short int mtu)
	{
	struct ifreq ifr;
	int r;

	memset(&ifr, 0, sizeof(ifr));
	strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
	ifr.ifr_mtu = mtu;
	r = ioctl(socket_afnet, mtu ? SIOCSIFMTU : SIOCGIFMTU, &ifr);
	if (r == -1)
	return -1;
	return ifr.ifr_mtu;
	}