1 files changed, 27 insertions, 18 deletions

diff --git a/sbin/dhclient/bpf.c b/sbin/dhclient/bpf.c
index 8a669e1..9f8e45f 100644
--- a/sbin/dhclient/bpf.c
+++ b/sbin/dhclient/bpf.c
@@ -90,11 +90,23 @@ if_register_bpf(struct interface_info *info)
 void
 if_register_send(struct interface_info *info)
 {
+	int sock, on = 1;
+
 	/*
 	 * If we're using the bpf API for sending and receiving, we
 	 * don't need to register this interface twice.
 	 */
 	info->wfdesc = info->rfdesc;
+
+	/*
+	 * Use raw socket for unicast send.
+	 */
+	if ((sock = socket(AF_INET, SOCK_RAW, IPPROTO_UDP)) == -1)
+		error("socket(SOCK_RAW): %m");
+	if (setsockopt(sock, IPPROTO_IP, IP_HDRINCL, &on,
+	    sizeof(on)) == -1)
+		error("setsockopt(IP_HDRINCL): %m");
+	info->ufdesc = sock;
 }
 
 /*
@@ -244,35 +256,32 @@ send_packet(struct interface_info *interface, struct dhcp_packet *raw,
 {
 	unsigned char buf[256];
 	struct iovec iov[2];
+	struct msghdr msg;
 	int result, bufp = 0;
-	int sock;
-
-	if (to->sin_addr.s_addr != INADDR_BROADCAST) {
-		note("SENDING DIRECT");
-		/* We know who the server is, send the packet via
-		   normal socket interface */
-
-		if ((sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) >= 0) {
-			result = sendto (sock, (char *)raw, len, 0,
-					 (struct sockaddr *)to, sizeof *to);
-			close(sock);
-			if (result > 0)
-				return result;
-			}
-		}
 
 	/* Assemble the headers... */
-	assemble_hw_header(interface, buf, &bufp, hto);
+	if (to->sin_addr.s_addr == INADDR_BROADCAST)
+		assemble_hw_header(interface, buf, &bufp, hto);
 	assemble_udp_ip_header(buf, &bufp, from.s_addr,
 	    to->sin_addr.s_addr, to->sin_port, (unsigned char *)raw, len);
 
-	/* Fire it off */
 	iov[0].iov_base = (char *)buf;
 	iov[0].iov_len = bufp;
 	iov[1].iov_base = (char *)raw;
 	iov[1].iov_len = len;
 
-	result = writev(interface->wfdesc, iov, 2);
+	/* Fire it off */
+	if (to->sin_addr.s_addr == INADDR_BROADCAST)
+		result = writev(interface->wfdesc, iov, 2);
+	else {
+		memset(&msg, 0, sizeof(msg));
+		msg.msg_name = (struct sockaddr *)to;
+		msg.msg_namelen = sizeof(*to);
+		msg.msg_iov = iov;
+		msg.msg_iovlen = 2;
+		result = sendmsg(interface->ufdesc, &msg, 0);
+	}
+
 	if (result < 0)
 		warning("send_packet: %m");
 	return (result);