debug IP multicast loopback

diff --git a/libs/midi++2/ipmidi_port.cc b/libs/midi++2/ipmidi_port.cc
index 6955bd9f86ab9c8506201039f039c997455a4118..be271f40251f78b1bf1ae7787c4bdef03b0b9fd3 100644 (file)
--- a/libs/midi++2/ipmidi_port.cc
+++ b/libs/midi++2/ipmidi_port.cc
@@ -194,7 +194,7 @@ IPMIDIPort::open_sockets (int base_port, const string& ifname)
 #endif
 
        struct ip_mreq mreq;
-       mreq.imr_multiaddr.s_addr = ::inet_addr("225.0.0.37");
+       mreq.imr_multiaddr.s_addr = ::inet_addr("225.0.0.37"); /* ipMIDI group multicast address */
        mreq.imr_interface.s_addr = if_addr_in.s_addr;
        if(::setsockopt (sockin, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) &mreq, sizeof(mreq)) < 0) {
                ::perror("setsockopt(IP_ADD_MEMBERSHIP)");
@@ -231,13 +231,27 @@ 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...
-       int loop = 0;
+       loop = 0;
        if (::setsockopt(sockout, 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)) {