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Make multicast sockets work under windows

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msdn article 737550 states that "the preferred method is to call the
bind function to associate a socket with a local IP address and then
join the multicast group. Although this order of operations is not
mandatory, it is strongly recommended".
Since binding to the multicast address seems to fail, let's try binding
to INADDR_ANY and joint thereafter.
This commit is contained in:
Torsten Dreyer
2011-05-27 21:06:06 +02:00
parent 3a07e2fe21
commit b06e38699a
1 changed files with 16 additions and 0 deletions
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16
simgear/io/raw_socket.cxx
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@@ -260,15 +260,31 @@ int Socket::bind ( const char* host, int port )
int result;
assert ( handle != -1 ) ;
IPAddress addr ( host, port ) ;
#if !defined(WINSOCK)
if( (result = ::bind(handle,(const sockaddr*)&addr,sizeof(IPAddress))) < 0 ) {
SG_LOG(SG_IO, SG_ALERT, "bind(" << host << ":" << port << ") failed. Errno " << errno << " (" << strerror(errno) << ")");
return result;
}
#endif
// 224.0.0.0 - 239.255.255.255 are multicast
// Usage of 239.x.x.x is recommended for local scope
// Reference: http://tools.ietf.org/html/rfc5771
if( ntohl(addr.getIP()) >= 0xe0000000 && ntohl(addr.getIP()) <= 0xefffffff ) {
#if defined(WINSOCK)
struct sockaddr_in a;
a.sin_addr.S_un.S_addr = INADDR_ANY;
a.sin_family = AF_INET;
a.sin_port = htons(port);
if( (result = ::bind(handle,(const sockaddr*)&a,sizeof(a))) < 0 ) {
SG_LOG(SG_IO, SG_ALERT, "bind(any:" << port << ") failed. Errno " << errno << " (" << strerror(errno) << ")");
return result;
}
#endif
struct ip_mreq mreq;
mreq.imr_multiaddr.s_addr = addr.getIP();
mreq.imr_interface.s_addr = htonl(INADDR_ANY);