Listen on loopback only with the -l option

patch by Mike Frysinger

--- a/mbmon.c
+++ b/mbmon.c
@@ -41,4 +41,5 @@
 static const char *MyName = "mbmon";
 int port = 0;
+uint32_t listen_addr = INADDR_ANY;
 
 int usage(void)
@@ -61,4 +62,5 @@
 "  -c count: repeat <count> times and exit\n"
 "  -P port: run in daemon mode, using given port for clients\n"
+"  -l: listen on local interface only\n"
 "  -T|F [1-7]: print Temperature|Fanspeed according to following styles\n"
 "	style1: data1\\n\n"
@@ -318,5 +320,5 @@
 	while ((ch = getopt(argc,argv,"VSIAfdDYe:p:s:c:T:F:tunNirh")) != -1) {
 #else
-	while ((ch = getopt(argc,argv,"VSIAfdDYe:p:c:T:F:tunNirhP:")) != -1) {
+	while ((ch = getopt(argc,argv,"VSIAfdDYe:p:c:T:F:tunNirhlP:")) != -1) {
 #endif
 	  switch(ch) {
@@ -371,4 +373,7 @@
 		probe_request = optarg;
 		break;
+	  case 'l':
+		listen_addr = INADDR_LOOPBACK;
+		break;
 	  case 'P':
 		port = atoi (optarg);
@@ -458,5 +463,5 @@
 		server.sin_family = AF_INET;
 		server.sin_port = htons (port);
-		server.sin_addr.s_addr = INADDR_ANY;
+		server.sin_addr.s_addr = htonl(listen_addr);
 		if (bind (fd, (struct sockaddr *) &server, sizeof (server)) < 0) {
 			perror("bind");