(socket utility) move ix::getFreePort to ixwebsocket library

ixwebsocket/IXGetFreePort.cpp

@@ -0,0 +1,97 @@
+/*
+ *  IXGetFreePort.cpp
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2019 Machine Zone. All rights reserved.
+ */
+
+// Using inet_addr will trigger an error on uwp without this
+// FIXME: use a different api
+#ifdef _WIN32
+#ifndef _WINSOCK_DEPRECATED_NO_WARNINGS
+#define _WINSOCK_DEPRECATED_NO_WARNINGS
+#endif
+#endif
+
+#include "IXGetFreePort.h"
+
+#include <ixwebsocket/IXNetSystem.h>
+#include <ixwebsocket/IXSocket.h>
+#include <random>
+#include <string>
+
+namespace ix
+{
+    int getAnyFreePortRandom()
+    {
+        std::random_device rd;
+        std::uniform_int_distribution<int> dist(1024 + 1, 65535);
+
+        return dist(rd);
+    }
+
+    int getAnyFreePort()
+    {
+        int sockfd;
+        if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+        {
+            return getAnyFreePortRandom();
+        }
+
+        int enable = 1;
+        if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, (char*) &enable, sizeof(enable)) < 0)
+        {
+            return getAnyFreePortRandom();
+        }
+
+        // Bind to port 0. This is the standard way to get a free port.
+        struct sockaddr_in server; // server address information
+        server.sin_family = AF_INET;
+        server.sin_port = htons(0);
+        server.sin_addr.s_addr = inet_addr("127.0.0.1");
+
+        if (bind(sockfd, (struct sockaddr*) &server, sizeof(server)) < 0)
+        {
+            Socket::closeSocket(sockfd);
+            return getAnyFreePortRandom();
+        }
+
+        struct sockaddr_in sa; // server address information
+        socklen_t len = sizeof(sa);
+        if (getsockname(sockfd, (struct sockaddr*) &sa, &len) < 0)
+        {
+            Socket::closeSocket(sockfd);
+            return getAnyFreePortRandom();
+        }
+
+        int port = ntohs(sa.sin_port);
+        Socket::closeSocket(sockfd);
+
+        return port;
+    }
+
+    int getFreePort()
+    {
+        while (true)
+        {
+#if defined(__has_feature)
+#if __has_feature(address_sanitizer)
+            int port = getAnyFreePortRandom();
+#else
+            int port = getAnyFreePort();
+#endif
+#else
+            int port = getAnyFreePort();
+#endif
+            //
+            // Only port above 1024 can be used by non root users, but for some
+            // reason I got port 7 returned with macOS when binding on port 0...
+            //
+            if (port > 1024)
+            {
+                return port;
+            }
+        }
+
+        return -1;
+    }
+} // namespace ix

ixwebsocket/IXGetFreePort.h

@@ -0,0 +1,12 @@
+/*
+ *  IXGetFreePort.h
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2019 Machine Zone. All rights reserved.
+ */
+
+#pragma once
+
+namespace ix
+{
+    int getFreePort();
+} // namespace ix

ixwebsocket/IXWebSocketVersion.h

@@ -6,4 +6,4 @@
 
 #pragma once
 
-#define IX_WEBSOCKET_VERSION "10.0.0"
+#define IX_WEBSOCKET_VERSION "10.0.1"