Added zts_set_service_port()

include/libzt.h

@@ -75,6 +75,18 @@
 extern "C" {
 #endif
 
+/**
+ * @brief (optional) Sets the port for the background libzt service. If this function is called
+ * with a port number between 1-65535 it will attempt to bind to that port. If it is called with
+ * a port number of 0 it will attempt to randomly search for an available port. If this function
+ * is never called, the service will try to bind on LIBZT_DEFAULT_PORT which is 9994.
+ *
+ * @usage Should be called at the beginning of your application before `zts_startjoin()`
+ * @param portno Port number
+ * @return 0 if successful; or -1 if failed
+ */
+ZT_SOCKET_API int ZTCALL zts_set_service_port(int portno);
+
 /**
  * @brief Starts libzt
  *

include/libztDefs.h

@@ -33,6 +33,10 @@
 #ifndef LIBZT_DEFINES_H
 #define LIBZT_DEFINES_H
 
+/**
+ * Default port that libzt will use to support all virtual communication
+ */
+#define LIBZT_DEFAULT_PORT 9994
 /**
  * Use ZeroTier Virtual Socket layer to abstract network stack raw API
  */

src/ZT1Service.cpp

@@ -55,6 +55,8 @@ std::string netDir;  // Where network .conf files are to be written
 
 ZeroTier::Mutex _multiplexer_lock;
 
+int servicePort = LIBZT_DEFAULT_PORT;
+
 #if defined(_WIN32)
 WSADATA wsaData;
 #include <Windows.h>
@@ -216,12 +218,12 @@ void *zts_start_service(void *thread_id)
 		DEBUG_ERROR("homeDir is empty, could not construct path");
 		return NULL;
 	}
-
-	// Generate random port for new service instance
-	unsigned int randp = 0;
-	ZeroTier::Utils::getSecureRandom(&randp,sizeof(randp));
-	// TODO: Better port random range selection
-	int servicePort = 9000 + (randp % 1000);
+	if (servicePort <= 0) {
+		DEBUG_INFO("no port specified, will bind to random port. use zts_set_service_port() if you want.");
+	}
+	else {
+		DEBUG_INFO("binding to port=%d", servicePort);
+	}
 	for (;;) {
 		zt1Service = ZeroTier::OneService::newInstance(homeDir.c_str(),servicePort);
 		switch(zt1Service->run()) {
@@ -229,7 +231,6 @@ void *zts_start_service(void *thread_id)
 			case ZeroTier::OneService::ONE_NORMAL_TERMINATION:
 				break;
 			case ZeroTier::OneService::ONE_UNRECOVERABLE_ERROR:
-				DEBUG_ERROR("ZTO service port = %d", servicePort);
 				DEBUG_ERROR("fatal error: %s",zt1Service->fatalErrorMessage().c_str());
 				break;
 			case ZeroTier::OneService::ONE_IDENTITY_COLLISION: {
@@ -292,6 +293,20 @@ int zts_get_address_at_index(
 	return err;
 }
 
+/****************************************************************************/
+/* ZeroTier Service Controls                                                */
+/****************************************************************************/
+
+int zts_set_service_port(int portno)
+{
+	if (portno > -1 && portno < 65535) {
+		// 0 is allowed, see docs
+		servicePort = portno;
+		return 0;
+	}
+	return -1;
+}
+
 int zts_get_address(const uint64_t nwid, struct sockaddr_storage *addr, 
 	const int address_family)
 {
@@ -432,13 +447,16 @@ int zts_start(const char *path, bool blocking = false)
 	if (blocking) { // block to prevent service calls before we're ready
 		ZT_NodeStatus status;
 		status.online = 0;
+		DEBUG_EXTRA("waiting for zerotier service thread to start");
 		while (zts_core_running() == false || zt1Service->getNode() == NULL) {
 			api_sleep(ZTO_WRAPPER_CHECK_INTERVAL);
 		}
+		DEBUG_EXTRA("waiting for node address assignment");
 		while (zt1Service->getNode()->address() <= 0) {
 			api_sleep(ZTO_WRAPPER_CHECK_INTERVAL);
 		}
-		DEBUG_INFO("node=%llx", zts_get_node_id());
+		DEBUG_EXTRA("node=%llx", zts_get_node_id());
+		DEBUG_EXTRA("waiting for node to come online");
 		while (status.online <= 0) {
 			api_sleep(ZTO_WRAPPER_CHECK_INTERVAL);
 			zt1Service->getNode()->status(&status);

test/selftest.cpp

@@ -2963,6 +2963,11 @@ int main(int argc , char *argv[])
 		// set start time here since we need to wait for both libzt instances to be online
 		DEBUG_TEST("app-thread, waiting for libzt to come online...\n");
 		uint64_t nwid = strtoull(nwidstr.c_str(),NULL,16);
+		int portno = LIBZT_DEFAULT_PORT;
+		if (zts_set_service_port(portno) < 0) {
+			DEBUG_TEST("error, invalid zt service port number: %d", portno);
+			exit(0);
+		}
 		zts_startjoin(path.c_str(), nwid);
 		uint64_t nodeId = zts_get_node_id();
 		DEBUG_TEST("I am %llx, %s", nodeId, me.c_str());