Simplify get_interfaces function, make it return NULL if we didn't find

the interface and abort dhcrelay with a more friendly message when we
don't have an address configured in the interface.

ok jca@

4 files changed, 31 insertions, 27 deletions

diff --git a/usr.sbin/dhcrelay/bpf.c b/usr.sbin/dhcrelay/bpf.c
index 9a498c98f23..d211b6f78cf 100644
--- a/usr.sbin/dhcrelay/bpf.c
+++ b/usr.sbin/dhcrelay/bpf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bpf.c,v 1.11 2016/05/28 07:00:18 natano Exp $ */
+/*	$OpenBSD: bpf.c,v 1.12 2016/12/08 09:29:50 rzalamena Exp $ */
 
 /* BPF socket interface code, originally contributed by Archie Cobbs. */
 
@@ -75,7 +75,7 @@ if_register_bpf(struct interface_info *info)
 		error("Can't open bpf device: %m");
 
 	/* Set the BPF device to point at this interface. */
-	if (ioctl(sock, BIOCSETIF, info->ifp) == -1)
+	if (ioctl(sock, BIOCSETIF, &info->ifr) == -1)
 		error("Can't attach interface %s to bpf device: %m",
 		    info->name);
 
diff --git a/usr.sbin/dhcrelay/dhcpd.h b/usr.sbin/dhcrelay/dhcpd.h
index c3a4648a6ff..6c922a40988 100644
--- a/usr.sbin/dhcrelay/dhcpd.h
+++ b/usr.sbin/dhcrelay/dhcpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhcpd.h,v 1.15 2016/12/07 13:19:18 rzalamena Exp $	*/
+/*	$OpenBSD: dhcpd.h,v 1.16 2016/12/08 09:29:50 rzalamena Exp $	*/
 
 /*
  * Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
@@ -76,7 +76,7 @@ struct interface_info {
 	size_t			 rbuf_max;
 	size_t			 rbuf_offset;
 	size_t			 rbuf_len;
-	struct ifreq		*ifp;
+	struct ifreq		 ifr;
 	int			 noifmedia;
 	int			 errors;
 	int			 dead;
diff --git a/usr.sbin/dhcrelay/dhcrelay.c b/usr.sbin/dhcrelay/dhcrelay.c
index d27d3e4a551..dfb31846947 100644
--- a/usr.sbin/dhcrelay/dhcrelay.c
+++ b/usr.sbin/dhcrelay/dhcrelay.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhcrelay.c,v 1.47 2016/12/07 20:03:22 patrick Exp $ */
+/*	$OpenBSD: dhcrelay.c,v 1.48 2016/12/08 09:29:50 rzalamena Exp $ */
 
 /*
  * Copyright (c) 2004 Henning Brauer <henning@cvs.openbsd.org>
@@ -115,6 +115,8 @@ main(int argc, char *argv[])
 				usage();
 
 			interfaces = get_interface(optarg, got_one);
+			if (interfaces == NULL)
+				error("interface '%s' not found", optarg);
 			break;
 		case 'o':
 			/* add the relay agent information option */
@@ -165,6 +167,9 @@ main(int argc, char *argv[])
 
 	if (interfaces == NULL)
 		error("no interface given");
+	if (interfaces->primary_address.s_addr == 0)
+		error("interface '%s' does not have an address",
+		    interfaces->name);
 
 	/* Default DHCP/BOOTP ports. */
 	server_port = htons(SERVER_PORT);
diff --git a/usr.sbin/dhcrelay/dispatch.c b/usr.sbin/dhcrelay/dispatch.c
index 90197304d5d..649a7e29200 100644
--- a/usr.sbin/dhcrelay/dispatch.c
+++ b/usr.sbin/dhcrelay/dispatch.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dispatch.c,v 1.12 2016/12/07 13:19:18 rzalamena Exp $	*/
+/*	$OpenBSD: dispatch.c,v 1.13 2016/12/08 09:29:50 rzalamena Exp $	*/
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -79,15 +79,15 @@ get_interface(const char *ifname, void (*handler)(struct protocol *))
 {
 	struct interface_info		*iface;
 	struct ifaddrs			*ifap, *ifa;
-	struct ifreq			*tif;
-	struct sockaddr_in		 foo;
+	struct sockaddr_in		*sin;
+	int				 found = 0;
 
 	if ((iface = calloc(1, sizeof(*iface))) == NULL)
 		error("failed to allocate memory");
 
 	if (strlcpy(iface->name, ifname, sizeof(iface->name)) >=
 	    sizeof(iface->name))
-		error("interface name too long");
+		error("interface name '%s' too long", ifname);
 
 	if (getifaddrs(&ifap) != 0)
 		error("getifaddrs failed");
@@ -101,6 +101,8 @@ get_interface(const char *ifname, void (*handler)(struct protocol *))
 		if (strcmp(ifname, ifa->ifa_name))
 			continue;
 
+		found = 1;
+
 		/*
 		 * If we have the capability, extract link information
 		 * and record it in a linked list.
@@ -120,31 +122,28 @@ get_interface(const char *ifname, void (*handler)(struct protocol *))
 			memcpy(iface->hw_address.haddr,
 			    LLADDR(foo), foo->sdl_alen);
 		} else if (ifa->ifa_addr->sa_family == AF_INET) {
-			struct iaddr addr;
+			/* We already have the primary address. */
+			if (iface->primary_address.s_addr != 0)
+				continue;
 
-			memcpy(&foo, ifa->ifa_addr, sizeof(foo));
-			if (foo.sin_addr.s_addr == htonl(INADDR_LOOPBACK))
+			sin = (struct sockaddr_in *)ifa->ifa_addr;
+			if (sin->sin_addr.s_addr == htonl(INADDR_LOOPBACK))
 				continue;
-			if (!iface->ifp) {
-				int len = IFNAMSIZ + ifa->ifa_addr->sa_len;
-
-				if ((tif = malloc(len)) == NULL)
-					error("no space to remember ifp");
-				strlcpy(tif->ifr_name, ifa->ifa_name, IFNAMSIZ);
-				memcpy(&tif->ifr_addr, ifa->ifa_addr,
-				    ifa->ifa_addr->sa_len);
-				iface->ifp = tif;
-				iface->primary_address = foo.sin_addr;
-			}
-			addr.len = 4;
-			memcpy(addr.iabuf, &foo.sin_addr.s_addr, addr.len);
+
+			iface->primary_address = sin->sin_addr;
 		}
 	}
 
 	freeifaddrs(ifap);
 
-	if (!iface->ifp)
-		error("%s: not found", iface->name);
+	if (!found) {
+		free(iface);
+		return (NULL);
+	}
+
+	if (strlcpy(iface->ifr.ifr_name, ifname,
+	    sizeof(iface->ifr.ifr_name)) >= sizeof(iface->ifr.ifr_name))
+		error("interface name '%s' too long", ifname);
 
 	/* Register the interface... */
 	if_register_receive(iface);