Resolve Bundle Manager Input/Output label ambiguity

[ardour.git] / libs / midi++2 / ipmidi_port.cc

diff --git a/libs/midi++2/ipmidi_port.cc b/libs/midi++2/ipmidi_port.cc
index be271f40251f78b1bf1ae7787c4bdef03b0b9fd3..fd5cb9a2395e727a457dda57104038439ea0429b 100644 (file)
--- a/libs/midi++2/ipmidi_port.cc
+++ b/libs/midi++2/ipmidi_port.cc
@@ -231,27 +231,43 @@ IPMIDIPort::open_sockets (int base_port, const string& ifname)
        addrout.sin_addr.s_addr = ::inet_addr("225.0.0.37");
        addrout.sin_port = htons (base_port);
 
-       int loop;
-       socklen_t size;
-       if (::getsockopt (sockin, IPPROTO_IP, IP_MULTICAST_LOOP, &loop, &size)) {
-               ::perror ("getsockopt(IP_MULTICAST_LOOP)");
-       } else {
-               cout << "********* 1. multicast loopback: " << loop << " size was " << size << endl;
-       }
-
        // Turn off loopback...
-       loop = 0;
-       if (::setsockopt(sockout, IPPROTO_IP, IP_MULTICAST_LOOP, (char *) &loop, sizeof (loop)) < 0) {
+       int loop = 0;
+
+#ifdef PLATFORM_WINDOWS
+
+       /* https://msdn.microsoft.com/en-us/library/windows/desktop/ms739161%28v=vs.85%29.aspx
+        *
+        * ------------------------------------------------------------------------------
+        * Note The Winsock version of the IP_MULTICAST_LOOP option is
+        * semantically different than the UNIX version of the
+        * IP_MULTICAST_LOOP option:
+        *
+        * In Winsock, the IP_MULTICAST_LOOP option applies only to the receive path.
+        * In the UNIX version, the IP_MULTICAST_LOOP option applies to the send path.
+        *
+        * For example, applications ON and OFF (which are easier to track than
+        * X and Y) join the same group on the same interface; application ON
+        * sets the IP_MULTICAST_LOOP option on, application OFF sets the
+        * IP_MULTICAST_LOOP option off. If ON and OFF are Winsock
+        * applications, OFF can send to ON, but ON cannot sent to OFF. In
+        * contrast, if ON and OFF are UNIX applications, ON can send to OFF,
+        * but OFF cannot send to ON.
+        * ------------------------------------------------------------------------------
+        *
+        * Alles klar? Gut! 
+        */
+
+       const int target_sock = sockin;
+#else
+       const int target_sock = sockout;
+#endif
+
+       if (::setsockopt (target_sock, IPPROTO_IP, IP_MULTICAST_LOOP, (char *) &loop, sizeof (loop)) < 0) {
                ::perror("setsockopt(IP_MULTICAST_LOOP)");
                return false;
        }
 
-       if (::getsockopt (sockin, IPPROTO_IP, IP_MULTICAST_LOOP, &loop, &size)) {
-               ::perror ("getsockopt(IP_MULTICAST_LOOP)");
-       } else {
-               cout << "********* 2. multicast loopback: " << loop << " size was " << size << endl;
-       }
-
 #ifndef PLATFORM_WINDOWS
 
        if (fcntl (sockin, F_SETFL, O_NONBLOCK)) {
@@ -315,10 +331,6 @@ IPMIDIPort::parse (framecnt_t timestamp)
        socklen_t slen = sizeof(sender);
        int r = ::recvfrom (sockin, (char *) buf, sizeof(buf), 0, (struct sockaddr *) &sender, &slen);
 
-       if (r != 18) {
-               cout << "IPMIDI: received from socket: " << r << endl;
-       }
-
        if (r >= 0) {
 
                _parser->set_timestamp (timestamp);