We can now detected primary addresses added or changed in BSD.

As such, we can wait for a 3RDPARTY to configure the interface, such as PPP.
We can then take the destination addess and automatically give it a default
route or any other DHCP option such as DNS servers.
This addresses #159.

13 files changed, 309 insertions, 117 deletions

diff --git a/configure.c b/configure.c
index d41b03ed..bb1bba50 100644
--- a/configure.c
+++ b/configure.c
@@ -497,9 +497,12 @@ add_subnet_route(struct rt *rt, const struct interface *iface)
 	struct rt *r;
 
 	if (iface->net.s_addr == INADDR_BROADCAST ||
-	    iface->net.s_addr == INADDR_ANY)
+	    iface->net.s_addr == INADDR_ANY ||
+	    (iface->state->options->options &
+	     (DHCPCD_INFORM | DHCPCD_STATIC) &&
+	     iface->state->options->req_addr.s_addr == INADDR_ANY))
 		return rt;
-	
+
 	r = xmalloc(sizeof(*r));
 	r->dest.s_addr = iface->addr.s_addr & iface->net.s_addr;
 	r->net.s_addr = iface->net.s_addr;
@@ -534,8 +537,8 @@ get_routes(const struct interface *iface) {
 	return get_option_routes(iface->state->new);
 }
 
-static void
-build_routes()
+void
+build_routes(void)
 {
 	struct rt *nrs = NULL, *dnr, *or, *rt, *rtn, *rtl, *lrt = NULL;
 	const struct interface *ifp;
@@ -591,7 +594,12 @@ static int
 delete_address(struct interface *iface)
 {
 	int retval;
+	struct if_options *ifo;
 
+	ifo = iface->state->options;
+	if (ifo->options & DHCPCD_INFORM ||
+	    (ifo->options & DHCPCD_STATIC && ifo->req_addr.s_addr == 0))
+		return 0;
 	syslog(LOG_DEBUG, "%s: deleting IP address %s/%d",
 	    iface->name,
 	    inet_ntoa(iface->addr),
@@ -616,10 +624,9 @@ configure(struct interface *iface)
 	sort_interfaces();
 
 	if (dhcp == NULL) {
-		if (iface->addr.s_addr != 0) {
-			build_routes();
+		build_routes();
+		if (iface->addr.s_addr != 0)
 			delete_address(iface);
-		}
 		run_script(iface);
 		return 0;
 	}
diff --git a/configure.h b/configure.h
index d103b6e5..58b78026 100644
--- a/configure.h
+++ b/configure.h
@@ -32,6 +32,7 @@
 
 int send_interface(int, const struct interface *);
 int run_script(const struct interface *);
+void build_routes(void);
 int configure(struct interface *);
 int route_deleted(const struct rt *);
 #endif
diff --git a/dhcp.c b/dhcp.c
index 2689b734..15b21c98 100644
--- a/dhcp.c
+++ b/dhcp.c
@@ -195,8 +195,13 @@ int make_option_mask(uint8_t *mask, const char *opts, int add)
 					if (opt->option == n)
 						match = 1;
 			}
-			if (match) {	
-				if (add == 1)
+			if (match) {
+				if (add == 2 && !(opt->type & IPV4)) {
+					free(o);
+					errno = EINVAL;
+					return -1;
+				}
+				if (add == 1 || add == 2)
 					add_option_mask(mask,
 					    opt->option);
 				else
diff --git a/dhcpcd-run-hooks.8.in b/dhcpcd-run-hooks.8.in
index 6e025ac1..89525697 100644
--- a/dhcpcd-run-hooks.8.in
+++ b/dhcpcd-run-hooks.8.in
@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd January 15, 2009
+.Dd March 19, 2009
 .Dt DHCPCD.SH 8 SMM
 .Os
 .Sh NAME
@@ -91,6 +91,8 @@ dhcpcd failed to contact any DHCP servers but did obtain an IPV4LL address.
 .It Dv STATIC
 dhcpcd has been configured with a static configuration which has not been
 obtained from a DHCP server.
+.It Dv 3RDPARTY
+dhcpcd is monitoring the interface for a 3rd party to give it an IP address.
 .It Dv TIMEOUT
 dhcpcd failed to contact any DHCP servers but was able to use an old lease.
 .It Dv EXPIRE
diff --git a/dhcpcd.8.in b/dhcpcd.8.in
index eae48484..a1edeebb 100644
--- a/dhcpcd.8.in
+++ b/dhcpcd.8.in
@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd March 10, 2009
+.Dd March 19, 2009
 .Dt DHCPCD 8 SMM
 .Os
 .Sh NAME
@@ -461,6 +461,19 @@ When discovering interfaces, the interface name must not match
 which is a space or comma separated list of patterns passed to
 .Xr fnmatch 3 .
 .El
+.Sh 3RDPARTY LINK MANAGEMENT
+Some interfaces require configuration by 3rd parties, such as PPP or VPN.
+When an interface configuration in
+.Nm
+is marked as STATIC or INFORM without an address then
+.Nm
+will monitor the interface until an address is added or removed from it and
+act accordingly.
+For point to point interfaces (like PPP), a default route to it's
+destination is automatically added to the configuration.
+If the point to point interface if configured for INFORM, then
+.Nm
+unicasts INFORM to the destination.
 .Sh NOTES
 .Nm
 requires a Berkley Packet Filter, or BPF device on BSD based systems and a
diff --git a/dhcpcd.c b/dhcpcd.c
index 752ca555..2448f5e2 100644
--- a/dhcpcd.c
+++ b/dhcpcd.c
@@ -33,6 +33,7 @@ const char copyright[] = "Copyright (c) 2006-2009 Roy Marples";
 #include <sys/uio.h>
 
 #include <arpa/inet.h>
+#include <net/route.h>
 
 #include <ctype.h>
 #include <errno.h>
@@ -663,7 +664,11 @@ configure_interface(struct interface *iface, int argc, char **argv)
 	free_options(ifs->options);
 	ifo = ifs->options = read_config(cffile, iface->name, iface->ssid);
 	add_options(ifo, argc, argv);
-
+	if (iface->flags & IFF_NOARP)
+		ifo->options &= ~(DHCPCD_ARP | DHCPCD_IPV4LL);
+	if (ifo->options & DHCPCD_LINK && carrier_status(iface->name) == -1)
+		ifo->options &= ~DHCPCD_LINK;
+	
 	if (ifo->metric != -1)
 		iface->metric = ifo->metric;
 
@@ -821,17 +826,44 @@ dhcp_message_new(struct in_addr *addr, struct in_addr *mask)
 		*p++ = DHO_SUBNETMASK;
 		*p++ = sizeof(mask->s_addr);
 		memcpy(p, &mask->s_addr, sizeof(mask->s_addr));
+		p+= sizeof(mask->s_addr);
 	}
 	*p++ = DHO_END;
 	return dhcp;
 }
 
+static int
+handle_3rdparty(struct interface *iface)
+{
+	struct if_options *ifo;
+	struct in_addr addr, net, dst;
+	
+	ifo = iface->state->options;
+	if (ifo->req_addr.s_addr != INADDR_ANY)
+		return 0;
+
+	if (get_address(iface->name, &addr, &net, &dst) == 1)
+		handle_ifa(RTM_NEWADDR, iface->name, &addr, &net, &dst);
+	else {
+		syslog(LOG_INFO,
+			"%s: waiting for 3rd party to configure IP address",
+			iface->name);
+		iface->state->reason = "3RDPARTY";
+		run_script(iface);
+	}
+	return 1;
+}
+
 static void
 start_static(struct interface *iface)
 {
-	struct if_options *ifo = iface->state->options;
+	struct if_options *ifo;
 
-	iface->state->offer = dhcp_message_new(&ifo->req_addr, &ifo->req_mask);
+	if (handle_3rdparty(iface))
+		return;
+	ifo = iface->state->options;
+	iface->state->offer =
+	    dhcp_message_new(&ifo->req_addr, &ifo->req_mask);
 	delete_timeout(NULL, iface);
 	bind_interface(iface);
 }
@@ -839,11 +871,12 @@ start_static(struct interface *iface)
 static void
 start_inform(struct interface *iface)
 {
-	struct if_options *ifo = iface->state->options;
+	if (handle_3rdparty(iface))
+		return;
 
-	ifo->options |= DHCPCD_STATIC;
+	iface->state->options->options |= DHCPCD_STATIC;
 	start_static(iface);
-	ifo->options &= ~DHCPCD_STATIC;
+	iface->state->options->options &= ~DHCPCD_STATIC;
 
 	iface->state->state = DHS_INFORM;
 	iface->state->xid = arc4random();
@@ -909,6 +942,7 @@ start_interface(void *arg)
 	struct timeval now;
 	uint32_t l;
 
+	handle_carrier(iface->name);
 	if (iface->carrier == LINK_DOWN) {
 		syslog(LOG_INFO, "%s: waiting for carrier", iface->name);
 		return;
@@ -930,9 +964,14 @@ start_interface(void *arg)
 		start_inform(iface);
 		return;
 	}
+	if (iface->hwlen == 0 && ifo->clientid[0] == '\0') {
+		syslog(LOG_WARNING, "%s: needs a clientid to configure",
+			iface->name);
+		return;
+	}
 	if (ifo->req_addr.s_addr) {
-		iface->state->offer = dhcp_message_new(&ifo->req_addr,
-		    &ifo->req_mask);
+		iface->state->offer =
+		    dhcp_message_new(&ifo->req_addr, &ifo->req_mask);
 		if (ifo->options & DHCPCD_REQUEST)
 			ifo->req_addr.s_addr = 0;
 		else {
@@ -1019,13 +1058,23 @@ init_state(struct interface *iface, int argc, char **argv)
 		iface->carrier = LINK_UNKNOWN;
 }
 
-static void
-handle_new_interface(const char *ifname)
+void
+handle_interface(int action, const char *ifname)
 {
 	struct interface *ifs, *ifp, *ifn, *ifl = NULL;
 	const char * const argv[] = { "dhcpcd", ifname };
 	int i;
 
+	if (action == -1) {
+		ifp = find_interface(ifname);
+		if (ifp != NULL)
+			stop_interface(ifp);
+		return;
+	} else if (action == 0) {
+		handle_carrier(ifname);
+		return;
+	}
+
 	/* If running off an interface list, check it's in it. */
 	if (ifc) {
 		for (i = 0; i < ifc; i++)
@@ -1055,24 +1104,91 @@ handle_new_interface(const char *ifname)
 	}
 }
 
-static void
-handle_remove_interface(const char *ifname)
+static int
+dhcp_message_add_addr(struct dhcp_message *dhcp, char c, struct in_addr *addr)
 {
-	struct interface *iface;
+	uint8_t *p;
+	size_t len;
 
-	iface = find_interface(ifname);
-	if (iface != NULL)
-		stop_interface(iface);
+	p = dhcp->options;
+	while (*p != DHO_END) {
+		p++;
+		p += *p + 1;
+	}
+
+	len = p - (uint8_t *)dhcp;
+	if (len + 6 > sizeof(*dhcp)) {
+		errno = ENOMEM;
+		return -1;
+	}
+
+	*p++ = c;
+	*p++ = sizeof(addr->s_addr);
+	memcpy(p, &addr->s_addr, sizeof(addr->s_addr));
+	p += sizeof(addr->s_addr);
+	*p = DHO_END;
+	return 0;
+}
+
+void
+handle_ifa(int type, const char *ifname,
+    struct in_addr *addr, struct in_addr *net, struct in_addr *dst)
+{
+	struct interface *ifp;
+	struct if_options *ifo;
+	int i;
+
+	if (addr->s_addr == INADDR_ANY)
+		return;
+	for (ifp = ifaces; ifp; ifp = ifp->next)
+		if (strcmp(ifp->name, ifname) == 0)
+			break;
+	if (ifp == NULL)
+		return;
+	ifo = ifp->state->options;
+	if ((ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC)) == 0 ||
+	    ifo->req_addr.s_addr != INADDR_ANY)
+		return;
+	
+	switch (type) {
+	case RTM_DELADDR:
+		if (ifp->state->new &&
+		    ifp->state->new->yiaddr == addr->s_addr)
+			drop_config(ifp, "EXPIRE");
+		break;
+	case RTM_NEWADDR:
+		if (ifo->options & DHCPCD_INFORM) {
+			ifp->state->state = DHS_INFORM;
+			ifp->state->xid = arc4random();
+			ifp->addr = *addr;
+			ifp->net = *net;
+			ifp->state->lease.server = *dst;
+			open_sockets(ifp);
+			send_inform(ifp);
+		} else {
+			free(ifp->state->old);
+			ifp->state->old = ifp->state->new;
+			ifp->state->new = dhcp_message_new(addr, net);
+			if (dst) {
+				for (i = 1; i < 255; i++)
+					if (has_option_mask(ifo->dstmask, i))
+						dhcp_message_add_addr(
+							ifp->state->new,
+							i, dst);
+			}
+			ifp->state->reason = "STATIC";
+			build_routes();
+			run_script(ifp);
+		}
+		break;
+	}
 }
 
 /* ARGSUSED */
 static void
 handle_link(_unused void *arg)
 {
-	if (manage_link(linkfd,
-		handle_carrier,
-		handle_new_interface,
-		handle_remove_interface) == -1)
+	if (manage_link(linkfd))
 		syslog(LOG_ERR, "manage_link: %m");
 }
 
diff --git a/dhcpcd.conf.5.in b/dhcpcd.conf.5.in
index e21e568e..988d74e9 100644
--- a/dhcpcd.conf.5.in
+++ b/dhcpcd.conf.5.in
@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd March 10, 2009
+.Dd March 19, 2009
 .Dt DHCPCD.CONF 5 SMM
 .Os
 .Sh NAME
@@ -143,9 +143,15 @@ It can be a variable to be used in
 .Xr dhcpcd-run-hooks 8
 or the numerical value.
 You can specify more options seperated by commas, spaces or more option lines.
-.Ic quiet
+.It Ic destination Ar option
+If
+.Nm
+detects an address added to a point to point interface (PPP, TUN, etc) then
+it will set the listed DHCP options to the destination address of the
+interface.
+.It Ic quiet
 Supress any dhcpcd output to the console, except for errors.
-.Ic reboot Ar seconds
+.It Ic reboot Ar seconds
 Allow
 .Ar reboot
 seconds before moving to the discover phase if we have an old lease to use.
@@ -192,6 +198,13 @@ Here is an example which configures a static address, routes and dns.
 .D1 static ip_address=192.168.0.10/24
 .D1 static routers=192.168.0.1
 .D1 static domain_name_servers=192.168.0.1
+.Pp
+Here is an example for PPP which gives the destination a default route.
+It uses the special destination keyword to insert the destination address
+into the value.
+.D1 interface ppp0
+.D1 static ip_address=
+.D1 destination routers
 .It Ic timeout Ar seconds
 The default timeout for waiting for a DHCP response is 30 seconds which may
 be too long or too short and can be changed here.
diff --git a/dhcpcd.h b/dhcpcd.h
index d8a5fabd..927f019f 100644
--- a/dhcpcd.h
+++ b/dhcpcd.h
@@ -82,6 +82,7 @@ struct interface {
 	char name[IF_NAMESIZE];
 	struct if_state *state;
 
+	int flags;
 	sa_family_t family;
 	unsigned char hwaddr[HWADDR_LEN];
 	size_t hwlen;
@@ -118,6 +119,9 @@ extern struct interface *ifaces;
 
 struct interface *find_interface(const char *);
 int handle_args(struct fd_list *, int, char **);
+void handle_interface(int, const char *);
+void handle_ifa(int, const char *,
+    struct in_addr *, struct in_addr *, struct in_addr *);
 void handle_exit_timeout(void *);
 void start_interface(void *);
 void start_discover(void *);
diff --git a/if-bsd.c b/if-bsd.c
index 8d5529ca..0db8b304 100644
--- a/if-bsd.c
+++ b/if-bsd.c
@@ -60,17 +60,16 @@
 #include "if-options.h"
 #include "net.h"
 
-#define ROUNDUP(a)							\
+#define ROUNDUP(a)							      \
 	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
+#define ADVANCE(x, n) (x += ROUNDUP((n)->sa_len))
 
-/* Darwin doesn't define this for some very odd reason */
-#ifndef SA_SIZE
-# define SA_SIZE(sa)							\
-	(  (!(sa) || ((struct sockaddr *)(sa))->sa_len == 0) ?		\
-	    sizeof(long)		:				\
-	    1 + ( (((struct sockaddr *)(sa))->sa_len - 1) |		\
-		(sizeof(long) - 1) ) )
-#endif
+/* FIXME: Why do we need to check for sa_family 255 */
+#define COPYOUT(sin, sa)						      \
+	sin.s_addr = ((sa) != NULL && ((sa)->sa_family == AF_INET ||	      \
+		(sa)->sa_family == 255))				      \
+	    ?								      \
+	    (((struct sockaddr_in *)sa)->sin_addr).s_addr : 0
 
 static int a_fd = -1;
 static int r_fd = -1;
@@ -139,11 +138,11 @@ if_address(const struct interface *iface, const struct in_addr *address,
 	memset(&ifa, 0, sizeof(ifa));
 	strlcpy(ifa.ifra_name, iface->name, sizeof(ifa.ifra_name));
 
-#define ADDADDR(_var, _addr) {						\
-		_s.sa = &_var;						\
-		_s.sin->sin_family = AF_INET;				\
-		_s.sin->sin_len = sizeof(*_s.sin);			\
-		memcpy(&_s.sin->sin_addr, _addr, sizeof(_s.sin->sin_addr)); \
+#define ADDADDR(_var, _addr) {						      \
+		_s.sa = &_var;						      \
+		_s.sin->sin_family = AF_INET;				      \
+		_s.sin->sin_len = sizeof(*_s.sin);			      \
+		memcpy(&_s.sin->sin_addr, _addr, sizeof(_s.sin->sin_addr));   \
 	}
 
 	ADDADDR(ifa.ifra_addr, address);
@@ -184,17 +183,17 @@ if_route(const struct interface *iface, const struct in_addr *dest,
 	size_t l;
 	int retval = 0;
 
-#define ADDSU(_su) {							\
-		l = SA_SIZE(&(_su.sa));					\
-		memcpy(bp, &(_su), l);					\
-		bp += l;						\
-	} 
-#define ADDADDR(_addr) {						\
-		memset (&su, 0, sizeof(su));				\
-		su.sin.sin_family = AF_INET;				\
-		su.sin.sin_len = sizeof(su.sin);			\
-		memcpy (&su.sin.sin_addr, _addr, sizeof(su.sin.sin_addr)); \
-		ADDSU(su);						\
+#define ADDSU(_su) {							      \
+		l = ROUNDUP(_su.sa.sa_len);				      \
+		memcpy(bp, &(_su), l);					      \
+		bp += l;						      \
+	}
+#define ADDADDR(_a) {							      \
+		memset (&su, 0, sizeof(su));				      \
+		su.sin.sin_family = AF_INET;				      \
+		su.sin.sin_len = sizeof(su.sin);			      \
+		memcpy (&su.sin.sin_addr, _a, sizeof(su.sin.sin_addr));	      \
+		ADDSU(su);						      \
 	}
 
 	memset(&rtm, 0, sizeof(rtm));
@@ -272,22 +271,38 @@ open_link_socket(void)
 	return fd;
 }
 
+static void
+get_addrs(int type, char *cp, struct sockaddr **sa)
+{
+	int i;
+
+	for (i = 0; i < RTAX_MAX; i++) {
+		if (type & (1 << i)) {
+			sa[i] = (struct sockaddr *)cp;
+#ifdef DEBUG
+			printf ("got %d %d %s\n", i, sa[i]->sa_family,
+			    inet_ntoa(((struct sockaddr_in *)sa[i])->
+				sin_addr));
+#endif
+			ADVANCE(cp, sa[i]);
+		} else
+			sa[i] = NULL;
+	}
+}
+
 #define BUFFER_LEN	2048
 int
-manage_link(int fd,
-    void (*if_carrier)(const char *),
-    void (*if_add)(const char *),
-    void (*if_remove)(const char *))
+manage_link(int fd)
 {
-	char buffer[2048], *p, *e;
+	char buffer[2048], *p, *e, *cp;
 	char ifname[IF_NAMESIZE];
 	ssize_t bytes;
 	struct rt_msghdr *rtm;
-	struct if_announcemsghdr *ifa;
+	struct if_announcemsghdr *ifan;
 	struct if_msghdr *ifm;
+	struct ifa_msghdr *ifam;
 	struct rt rt;
-	struct sockaddr *sa;
-	struct sockaddr_in *sin;
+	struct sockaddr *sa, *rti_info[RTAX_MAX];
 
 	for (;;) {
 		bytes = read(fd, buffer, BUFFER_LEN);
@@ -303,13 +318,13 @@ manage_link(int fd,
 			rtm = (struct rt_msghdr *)(void *)p;
 			switch(rtm->rtm_type) {
 			case RTM_IFANNOUNCE:
-				ifa = (struct if_announcemsghdr *)(void *)p;
-				switch(ifa->ifan_what) {
+				ifan = (struct if_announcemsghdr *)(void *)p;
+				switch(ifan->ifan_what) {
 				case IFAN_ARRIVAL:
-					if_add(ifa->ifan_name);
+					handle_interface(1, ifan->ifan_name);
 					break;
 				case IFAN_DEPARTURE:
-					if_remove(ifa->ifan_name);
+					handle_interface(-1, ifan->ifan_name);
 					break;
 				}
 				break;
@@ -317,7 +332,7 @@ manage_link(int fd,
 				ifm = (struct if_msghdr *)(void *)p;
 				memset(ifname, 0, sizeof(ifname));
 				if (if_indextoname(ifm->ifm_index, ifname))
-					if_carrier(ifname);
+					handle_interface(0, ifname);
 				break;
 			case RTM_DELETE:
 				if (!(rtm->rtm_addrs & RTA_DST) ||
@@ -326,26 +341,30 @@ manage_link(int fd,
 					break;
 				if (rtm->rtm_pid == getpid())
 					break;
-				sa = (struct sockaddr *)(rtm + 1);
+				cp = (char *)(void *)(rtm + 1);
+				sa = (struct sockaddr *)(void *)cp;
 				if (sa->sa_family != AF_INET)
 					break;
-				rt.next = NULL;
+				get_addrs(rtm->rtm_addrs, cp, rti_info);
 				rt.iface = NULL;
-				sin = (struct sockaddr_in *)(void *)sa;
-				memcpy(&rt.dest.s_addr, &sin->sin_addr.s_addr,
-				    sizeof(rt.dest.s_addr));
-				sa = (struct sockaddr *)
-				    (ROUNDUP(sa->sa_len) + (char *)sa);
-				sin = (struct sockaddr_in *)(void *)sa;
-				memcpy(&rt.gate.s_addr, &sin->sin_addr.s_addr,
-				    sizeof(rt.gate.s_addr));
-				sa = (struct sockaddr *)
-				    (ROUNDUP(sa->sa_len) + (char *)sa);
-				sin = (struct sockaddr_in *)(void *)sa;
-				memcpy(&rt.net.s_addr, &sin->sin_addr.s_addr,
-				    sizeof(rt.net.s_addr));
+				rt.next = NULL;
+				COPYOUT(rt.dest, rti_info[RTAX_DST]);
+				COPYOUT(rt.net, rti_info[RTAX_NETMASK]);
+				COPYOUT(rt.gate, rti_info[RTAX_GATEWAY]);
 				route_deleted(&rt);
 				break;
+			case RTM_DELADDR:
+			case RTM_NEWADDR:
+				ifam = (struct ifa_msghdr *)(void *)p;
+				cp = (char *)(void *)(ifam + 1);
+				get_addrs(ifam->ifam_addrs, cp, rti_info);
+				COPYOUT(rt.dest, rti_info[RTAX_IFA]);
+				COPYOUT(rt.net, rti_info[RTAX_NETMASK]);
+				COPYOUT(rt.gate, rti_info[RTAX_BRD]);
+				if (if_indextoname(ifam->ifam_index, ifname))
+					handle_ifa(rtm->rtm_type, ifname,
+					    &rt.dest, &rt.net, &rt.gate);
+				break;
 			}
 		}
 	}
@@ -391,15 +410,12 @@ discover_link(struct interface **ifs, int argc, char * const *argv,
 		ifp->hwlen = sdl->sdl_alen;
 		memcpy(ifp->hwaddr, LLADDR(sdl), sdl->sdl_alen);
 		break;
-	default:
-		/* Don't needlessly spam console on startup */
-		if (!(options & DHCPCD_MASTER &&
-			!(options & DHCPCD_DAEMONISED) &&
-			options & DHCPCD_QUIET))
-			syslog(LOG_ERR, "%s: unsupported interface type",
-			    ifr->ifr_name);
-		free(ifp);
-		ifp = NULL;
+	case IFT_LOOP:
+		/* We don't allow loopback unless requested */
+		if (argc == 0 && ifac == 0) {
+			free(ifp);
+			ifp = NULL;
+		}
 		break;
 	}
 	if (ifl)
@@ -413,6 +429,7 @@ discover_interfaces(int argc, char * const *argv)
 {
 	struct interface *ifs = NULL;
 
-	do_interface(NULL, discover_link, &ifs, argc, argv, NULL, NULL, 2);
+	do_interface(NULL, discover_link, &ifs, argc, argv,
+			NULL, NULL, NULL, 2);
 	return ifs;
 }
diff --git a/if-options.c b/if-options.c
index c49031df..e7c38d24 100644
--- a/if-options.c
+++ b/if-options.c
@@ -78,6 +78,7 @@ const struct option cf_options[] = {
 	{"clientid",        optional_argument, NULL, 'I'},
 	{"nolink",          no_argument,       NULL, 'K'},
 	{"noipv4ll",        no_argument,       NULL, 'L'},
+	{"destination",     required_argument, NULL, 'N'},
 	{"nooption",        optional_argument, NULL, 'O'},
 	{"require",         required_argument, NULL, 'Q'},
 	{"static",          required_argument, NULL, 'S'},
@@ -543,6 +544,16 @@ parse_option(struct if_options *ifo, int opt, const char *arg)
 	case 'L':
 		ifo->options &= ~DHCPCD_IPV4LL;
 		break;
+	case 'N':
+		if (make_option_mask(ifo->dstmask, arg, 2) != 0) {
+			if (errno == EINVAL)
+				syslog(LOG_ERR, "option `%s' does not take"
+				    " an IPv4 address", arg);
+			else
+				syslog(LOG_ERR, "unknown otpion `%s'", arg);
+			return -1;
+		}
+		break;
 	case 'O':
 		if (make_option_mask(ifo->requestmask, arg, -1) != 0 ||
 		    make_option_mask(ifo->requiremask, arg, -1) != 0 ||
@@ -608,8 +619,8 @@ parse_option(struct if_options *ifo, int opt, const char *arg)
 				rt->next = xmalloc(sizeof(*rt));
 				rt = rt->next;
 			}
-			rt->dest.s_addr = 0;
-			rt->net.s_addr = 0;
+			rt->dest.s_addr = INADDR_ANY;
+			rt->net.s_addr = INADDR_ANY;
 			rt->next = NULL;
 			if (parse_addr(&rt->gate, NULL, p) == -1)
 				return -1;
diff --git a/if-options.h b/if-options.h
index 98c2f951..39c390f3 100644
--- a/if-options.h
+++ b/if-options.h
@@ -77,6 +77,7 @@ struct if_options {
 	uint8_t requestmask[256 / 8];
 	uint8_t requiremask[256 / 8];
 	uint8_t nomask[256 / 8];
+	uint8_t dstmask[256 / 8];
 	uint32_t leasetime;
 	time_t timeout;
 	time_t reboot;
diff --git a/net.c b/net.c
index b9cb280c..bfe1fd35 100644
--- a/net.c
+++ b/net.c
@@ -174,7 +174,7 @@ hwaddr_aton(unsigned char *buffer, const char *addr)
 struct interface *
 init_interface(const char *ifname)
 {
-	int s, arpable;
+	int s;
 	struct ifreq ifr;
 	struct interface *iface = NULL;
 
@@ -187,12 +187,10 @@ init_interface(const char *ifname)
 	strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
 	if (ioctl(s, SIOCGIFFLAGS, &ifr) == -1)
 		goto eexit;
-	if (ifr.ifr_flags & IFF_LOOPBACK || ifr.ifr_flags & IFF_POINTOPOINT)
-		goto eexit;
-	arpable = !(ifr.ifr_flags & IFF_NOARP);
 
 	iface = xzalloc(sizeof(*iface));
 	strlcpy(iface->name, ifname, sizeof(iface->name));
+	iface->flags = ifr.ifr_flags;
 	/* We reserve the 100 range for virtual interfaces, if and when
 	 * we can work them out. */
 	iface->metric = 200 + if_nametoindex(iface->name);
@@ -243,7 +241,6 @@ init_interface(const char *ifname)
 		goto eexit;
 	snprintf(iface->leasefile, sizeof(iface->leasefile),
 	    LEASEFILE, ifname);
-	iface->arpable = arpable;
 	/* 0 is a valid fd, so init to -1 */
 	iface->raw_fd = -1;
 	iface->udp_fd = -1;
@@ -277,7 +274,7 @@ int
 do_interface(const char *ifname,
     void (*do_link)(struct interface **, int, char * const *, struct ifreq *),
     struct interface **ifs, int argc, char * const *argv,
-    struct in_addr *addr, struct in_addr *net, int act)
+    struct in_addr *addr, struct in_addr *net, struct in_addr *dst, int act)
 {
 	int s;
 	struct ifconf ifc;
@@ -348,6 +345,16 @@ do_interface(const char *ifname,
 				continue;
 			netmask = sin->sin_addr.s_addr;
 			if (act == 1) {
+				if (dst) {
+					sin = (struct sockaddr_in *)
+						(void *)&ifr->ifr_dstaddr;
+					if (ioctl(s, SIOCGIFDSTADDR, ifr)
+					    == -1)
+						dst->s_addr = INADDR_ANY;
+					else
+						dst->s_addr =
+						    sin->sin_addr.s_addr;
+				}
 				addr->s_addr = address;
 				net->s_addr = netmask;
 				retval = 1;
@@ -436,12 +443,10 @@ carrier_status(const char *ifname)
 	if (retval == 1) {
 		memset(&ifmr, 0, sizeof(ifmr));
 		strlcpy(ifmr.ifm_name, ifr.ifr_name, sizeof(ifmr.ifm_name));
+		retval = -1;
 		if (ioctl(s, SIOCGIFMEDIA, &ifmr) != -1 &&
 		    ifmr.ifm_status & IFM_AVALID)
-		{
-			if (!(ifmr.ifm_status & IFM_ACTIVE))
-				retval = 0;
-		}
+			retval = (ifmr.ifm_status & IFM_ACTIVE) ? 1 : 0;
 	}
 #endif
 	close(s);
diff --git a/net.h b/net.h
index cbac54b5..f0ff3ad0 100644
--- a/net.h
+++ b/net.h
@@ -106,7 +106,7 @@ int up_interface(const char *);
 int do_interface(const char *,
     void (*)(struct interface **, int, char * const *, struct ifreq *),
     struct interface **, int, char * const *,
-    struct in_addr *, struct in_addr *, int);
+    struct in_addr *, struct in_addr *, struct in_addr *, int);
 int if_address(const struct interface *,
     const struct in_addr *, const struct in_addr *,
     const struct in_addr *, int);
@@ -115,9 +115,9 @@ int if_address(const struct interface *,
 #define del_address(iface, addr, net)					\
 	if_address(iface, addr, net, NULL, -1)
 #define has_address(iface, addr, net)					\
-	do_interface(iface, NULL, NULL, 0, NULL, addr, net, 0)
-#define get_address(iface, addr, net)					\
-	do_interface(iface, NULL, NULL, 0, NULL, addr, net, 1)
+	do_interface(iface, NULL, NULL, 0, NULL, addr, net, NULL, 0)
+#define get_address(iface, addr, net, dst)				\
+	do_interface(iface, NULL, NULL, 0, NULL, addr, net, dst, 1)
 
 int if_route(const struct interface *, const struct in_addr *,
     const struct in_addr *, const struct in_addr *, int, int);
@@ -147,9 +147,6 @@ ssize_t get_raw_packet(struct interface *, int, void *, ssize_t);
 
 int init_socket(void);
 int open_link_socket(void);
-int manage_link(int,
-    void (*)(const char *),
-    void (*)(const char *),
-    void (*)(const char *));
+int manage_link(int);
 int carrier_status(const char *);
 #endif