X-Git-Url: https://www.tinc-vpn.org/git/browse?a=blobdiff_plain;ds=sidebyside;f=src%2Ftincctl.c;h=1c96524dc71fe1da4da645b71459206b2c248333;hb=37cca72e6c973b77b5d11dcf721ae050edc23586;hp=a49654847f158d74c0cbafce1e9307a45c768122;hpb=d1e01bc880a6970050e55f19bafe8eaf1f0b9be2;p=tinc

diff --git a/src/tincctl.c b/src/tincctl.c
index a4965484..1c96524d 100644
--- a/src/tincctl.c
+++ b/src/tincctl.c
@@ -1657,6 +1657,66 @@ bool check_id(const char *name) {
 	return true;
 }
 
+static bool try_bind(int port) {
+	struct addrinfo *ai = NULL;
+	struct addrinfo hint = {
+		.ai_flags = AI_PASSIVE,
+		.ai_family = AF_UNSPEC,
+		.ai_socktype = SOCK_STREAM,
+		.ai_protocol = IPPROTO_TCP,
+	};
+
+	char portstr[16];
+	snprintf(portstr, sizeof portstr, "%d", port);
+
+	if(getaddrinfo(NULL, portstr, &hint, &ai) || !ai)
+		return false;
+
+	while(ai) {
+		int fd = socket(ai->ai_family, SOCK_STREAM, IPPROTO_TCP);
+		if(!fd)
+			return false;
+		int result = bind(fd, ai->ai_addr, ai->ai_addrlen);
+		closesocket(fd);
+		if(result)
+			return false;
+		ai = ai->ai_next;
+	}
+
+	return true;
+}
+
+int check_port(char *name) {
+	if(try_bind(655))
+		return 655;
+
+	fprintf(stderr, "Warning: could not bind to port 655. ");
+
+	srand(time(NULL));
+
+	for(int i = 0; i < 100; i++) {
+		int port = 0x1000 + (rand() & 0x7fff);
+		if(try_bind(port)) {
+			char *filename;
+			xasprintf(&filename, "%s" SLASH "hosts" SLASH "%s", confbase, name);
+			FILE *f = fopen(filename, "a");
+			free(filename);
+			if(!f) {
+				fprintf(stderr, "Please change tinc's Port manually.\n");
+				return 0;
+			}
+
+			fprintf(f, "Port = %d\n", port);
+			fclose(f);
+			fprintf(stderr, "Tinc will instead listen on port %d.\n", port);
+			return port;
+		}
+	}
+
+	fprintf(stderr, "Please change tinc's Port manually.\n");
+	return 0;
+}
+
 static int cmd_init(int argc, char *argv[]) {
 	if(!access(tinc_conf, F_OK)) {
 		fprintf(stderr, "Configuration file %s already exists!\n", tinc_conf);
@@ -1725,6 +1785,8 @@ static int cmd_init(int argc, char *argv[]) {
 	if(!rsa_keygen(2048, false) || !ecdsa_keygen(false))
 		return 1;
 
+	check_port(name);
+
 #ifndef HAVE_MINGW
 	char *filename;
 	xasprintf(&filename, "%s" SLASH "tinc-up", confbase);