Add interface deduplication in interface init function

This was triggering a bug where the TCP server fails to start.

src/if.c

@@ -282,7 +282,7 @@ if_init_all(char *ifs_name[MAX_INTERFACES], int ifs_n,
 			interface * new_ifs, int *new_ifs_n)
 {
 	struct rtnl_handle rth;
-	int ret = 0, i, n;
+	int ret = 0, i, j, n, dedup;
 
 	if (rtnl_open(&rth, 0) < 0) {
 		error("Cannot open the rtnetlink socket to talk to the kernel's "
@@ -300,7 +300,16 @@ if_init_all(char *ifs_name[MAX_INTERFACES], int ifs_n,
 		*new_ifs_n = ret;
 	} else {
 		for (i = 0, n = 0; i < ifs_n; i++) {
-
+			dedup = 0;
+			for(j=0; j < n; j++) {
+				if(strcmp(ifs_name[i], new_ifs[j].dev_name) == 0) {
+					dedup = 1;
+					break;
+				}
+			}
+			if(dedup) {
+				continue;
+			}
 			new_ifs[n].dev_idx = ll_name_to_index(ifs_name[n]);
 			if (!new_ifs[n].dev_idx) {
 				error("Cannot initialize the %s interface. "