X-Git-Url: http://git.meshlink.io/?a=blobdiff_plain;f=src%2Fmeshlink.c;h=c6b14b8f043c1b0bdb4c38b6db8aa687651659b7;hb=e306efba0aa513ae498b84b7f383b05365022092;hp=fbacfd4a4131a813d8f2119a11472303a00f4886;hpb=2224a56ea44bffdafbe29ba7b74d1a0adb0cbd95;p=meshlink

diff --git a/src/meshlink.c b/src/meshlink.c
index fbacfd4a..c6b14b8f 100644
--- a/src/meshlink.c
+++ b/src/meshlink.c
@@ -537,26 +537,52 @@ static bool try_bind(int port) {
 		return false;
 	}
 
-	//while(ai) {
+	bool success = false;
+
 	for(struct addrinfo *aip = ai; aip; aip = aip->ai_next) {
-		int fd = socket(aip->ai_family, SOCK_STREAM, IPPROTO_TCP);
+		/* Try to bind to TCP. */
 
-		if(!fd) {
-			freeaddrinfo(ai);
-			return false;
+		int tcp_fd = socket(aip->ai_family, SOCK_STREAM, IPPROTO_TCP);
+
+		if(tcp_fd == -1) {
+			continue;
 		}
 
-		int result = bind(fd, aip->ai_addr, aip->ai_addrlen);
-		closesocket(fd);
+		int result = bind(tcp_fd, aip->ai_addr, aip->ai_addrlen);
+		closesocket(tcp_fd);
 
 		if(result) {
-			freeaddrinfo(ai);
-			return false;
+			if(errno == EADDRINUSE) {
+				/* If this port is in use for any address family, avoid it. */
+				success = false;
+				break;
+			} else {
+				continue;
+			}
 		}
+
+		/* If TCP worked, then we require that UDP works as well. */
+
+		int udp_fd = socket(aip->ai_family, SOCK_DGRAM, IPPROTO_UDP);
+
+		if(udp_fd == -1) {
+			success = false;
+			break;
+		}
+
+		result = bind(udp_fd, aip->ai_addr, aip->ai_addrlen);
+		closesocket(udp_fd);
+
+		if(result) {
+			success = false;
+			break;
+		}
+
+		success = true;
 	}
 
 	freeaddrinfo(ai);
-	return true;
+	return success;
 }
 
 static int check_port(meshlink_handle_t *mesh) {