From 8f2db4afddf109e59c7ec0cdb7ad79db75d698e5 Mon Sep 17 00:00:00 2001
From: Guus Sliepen <guus@tinc-vpn.org>
Date: Fri, 26 Jul 2013 14:17:15 +0200
Subject: [PATCH] Choose a different Port when 655 isn't available when doing
"tinc init".
If port 655 cannot be bound to when using the init command, tinc will try to
find a random port number that can be bound to, and will add the appropriate
Port variable to its host config file. A warning will be printed as well.
---
src/tincctl.c | 58 +++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 58 insertions(+)
diff --git a/src/tincctl.c b/src/tincctl.c
index a496548..16fa4b1 100644
--- a/src/tincctl.c
+++ b/src/tincctl.c
@@ -1657,6 +1657,35 @@ 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;
+}
+
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 +1754,35 @@ static int cmd_init(int argc, char *argv[]) {
if(!rsa_keygen(2048, false) || !ecdsa_keygen(false))
return 1;
+
+ if(!try_bind(655)) {
+ srand(time(NULL));
+ int port = 0;
+ for(int i = 0; i < 100; i++) {
+ port = 0x1000 + (rand() & 0x7fff);
+ if(try_bind(port))
+ break;
+ port = 0;
+ }
+ if(port) {
+ char *filename;
+ xasprintf(&filename, "%s" SLASH "hosts" SLASH "%s", confbase, name);
+ FILE *f = fopen(filename, "a");
+ free(filename);
+ if(!f) {
+ port = 0;
+ } else {
+ fprintf(f, "Port = %d\n", port);
+ fclose(f);
+ }
+ }
+
+ if(!port)
+ fprintf(stderr, "Warning: could not bind to port 655. Please change tinc's Port manually.\n");
+ else
+ fprintf(stderr, "Warning: could not bind to port 655. Tinc will instead listen on port %d.\n", port);
+ }
+
#ifndef HAVE_MINGW
char *filename;
xasprintf(&filename, "%s" SLASH "tinc-up", confbase);
--
2.25.1