fix networking library to allow multicast

core/src/utils/net.cpp

@@ -86,14 +86,14 @@ namespace net {
         addr.sin_port = htons(port);
     }
 
-    std::string Address::getIPStr() {
+    std::string Address::getIPStr() const {
         char buf[128];
         IP_t ip = getIP();
         sprintf(buf, "%d.%d.%d.%d", (ip >> 24) & 0xFF, (ip >> 16) & 0xFF, (ip >> 8) & 0xFF, ip & 0xFF);
         return buf;
     }
 
-    IP_t Address::getIP() {
+    IP_t Address::getIP() const {
         return htonl(addr.sin_addr.s_addr);
     }
 
@@ -101,7 +101,7 @@ namespace net {
         addr.sin_addr.s_addr = htonl(ip);
     }
 
-    int Address::getPort() {
+    int Address::getPort() const {
         return htons(addr.sin_port);
     }
 
@@ -109,6 +109,11 @@ namespace net {
         addr.sin_port = htons(port);
     }
 
+    bool Address::isMulticast() const {
+        IP_t ip = getIP();
+        return (ip >> 28) == 0b1110;
+    }
+
     // === Socket functions ===
 
     Socket::Socket(SockHandle_t sock, const Address* raddr) {
@@ -160,8 +165,8 @@ namespace net {
 
                 // Set timeout
                 timeval tv;
-                tv.tv_sec = 0;
-                tv.tv_usec = timeout * 1000;
+                tv.tv_sec = timeout / 1000;
+                tv.tv_usec = (timeout - tv.tv_sec*1000) * 1000;
 
                 // Wait for data
                 int err = select(sock+1, &set, NULL, &set, (timeout > 0) ? &tv : NULL);
@@ -225,8 +230,8 @@ namespace net {
 
         // Define timeout
         timeval tv;
-        tv.tv_sec = 0;
-        tv.tv_usec = timeout * 1000;
+        tv.tv_sec = timeout / 1000;
+        tv.tv_usec = (timeout - tv.tv_sec*1000) * 1000;
 
         // Wait for data or error
         if (timeout != NONBLOCKING) {
@@ -382,6 +387,18 @@ namespace net {
         // Create socket
         SockHandle_t s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
 
+        // If the remote address is multicast, allow multicast connections
+#ifdef _WIN32
+        const char enable = raddr.isMulticast();
+#else
+        int enable = raddr.isMulticast();
+#endif
+        if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int)) < 0) {
+            closeSocket(s);
+            throw std::runtime_error("Could not configure socket");
+            return NULL;
+        }
+
         // Bind socket to local port
         if (bind(s, (sockaddr*)&laddr.addr, sizeof(sockaddr_in))) {
             closeSocket(s);

core/src/utils/net.h

@@ -67,13 +67,13 @@ namespace net {
          * Get the IP address.
          * @return IP address in standard string format.
          */
-        std::string getIPStr();
+        std::string getIPStr() const;
 
         /**
          * Get the IP address.
          * @return IP address in host byte order.
          */
-        IP_t getIP();
+        IP_t getIP() const;
 
         /**
          * Set the IP address.
@@ -85,7 +85,7 @@ namespace net {
          * Get the TCP/UDP port.
          * @return TCP/UDP port number.
          */
-        int getPort();
+        int getPort() const;
 
         /**
          * Set the TCP/UDP port.
@@ -93,6 +93,12 @@ namespace net {
          */
         void setPort(int port);
 
+        /**
+         * Check if the address is multicast.
+         * @return True if multicast, false if not.
+        */
+        bool isMulticast() const;
+
         struct sockaddr_in addr;
     };
 
@@ -246,7 +252,7 @@ namespace net {
 
     /**
      * Create UDP socket.
-     * @param raddr Remote address.
+     * @param raddr Remote address. Set to a multicast address to allow multicast.
      * @param laddr Local address to bind the socket to.
      * @return Socket instance on success, Throws runtime_error otherwise.
      */
@@ -254,7 +260,7 @@ namespace net {
 
     /**
      * Create UDP socket.
-     * @param rhost Remote hostname or IP address.
+     * @param rhost Remote hostname or IP address. Set to a multicast address to allow multicast.
      * @param rport Remote port.
      * @param laddr Local address to bind the socket to.
      * @return Socket instance on success, Throws runtime_error otherwise.
@@ -263,7 +269,7 @@ namespace net {
 
     /**
      * Create UDP socket.
-     * @param raddr Remote address.
+     * @param raddr Remote address. Set to a multicast address to allow multicast.
      * @param lhost Local hostname or IP used to bind the socket (optional, "0.0.0.0" for Any).
      * @param lpost Local port used to bind the socket to (optional, 0 to allocate automatically).
      * @return Socket instance on success, Throws runtime_error otherwise.
@@ -272,7 +278,7 @@ namespace net {
 
     /**
      * Create UDP socket.
-     * @param rhost Remote hostname or IP address.
+     * @param rhost Remote hostname or IP address. Set to a multicast address to allow multicast.
      * @param rport Remote port.
      * @param lhost Local hostname or IP used to bind the socket (optional, "0.0.0.0" for Any).
      * @param lpost Local port used to bind the socket to (optional, 0 to allocate automatically).