confd: add netlink condition to dhcp-client, <net/IFNAME/running>

This patch ensures that the DHCP client is not started until the
interface is up and running (link).  If the interface goes down,
or loses link, the client is stopped and everything learned from
the server (address, routes, DNS/NTP servers, etc.) is remvoed.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/confd/src/infix-dhcp.c

@@ -244,12 +244,12 @@ static void add(const char *ifname, struct lyd_node *cfg)
 
 	fprintf(fp, "# Generated by Infix confd\n");
 	fprintf(fp, "metric=%s\n", metric);
-	fprintf(fp, "service <!> name:dhcp :%s \\\n"
+	fprintf(fp, "service <!> name:dhcp :%s <net/%s/running> \\\n"
 		"	[2345] udhcpc -f -p /run/dhcp-%s.pid -t 10 -T 3 -A 10 %s -S -R \\\n"
 		"		-o %s \\\n"
 		"		-i %s %s %s %s \\\n"
 		"		-- DHCP client @%s\n",
-		ifname, ifname, do_arp,
+		ifname, ifname, ifname, do_arp,
 		options,
 		ifname, args ?: "", ipcache ?: "", vendor, ifname);
 	fclose(fp);