public static unsafe SocketError GetMulticastOption(SafeCloseSocket handle, SocketOptionName optionName, out MulticastOption optionValue)
{
int optLevel, optName;
GetPlatformOptionInfo(SocketOptionLevel.IP, optionName, out optLevel, out optName);
var mreqn = new Interop.libc.ip_mreqn();
var optLen = (uint)sizeof(Interop.libc.ip_mreqn);
int err = Interop.libc.getsockopt(handle.FileDescriptor, optLevel, optName, &mreqn, &optLen);
if (err == -1)
{
optionValue = default(MulticastOption);
return GetLastSocketError();
}
var multicastAddress = new IPAddress((long)mreqn.imr_multiaddr.s_addr);
var multicastInterface = new IPAddress((long)mreqn.imr_address.s_addr);
optionValue = new MulticastOption(multicastAddress, multicastInterface);
return SocketError.Success;
}
public static unsafe SocketError SetMulticastOption(SafeCloseSocket handle, SocketOptionName optionName, MulticastOption optionValue)
{
int optLevel, optName;
GetPlatformOptionInfo(SocketOptionLevel.IP, optionName, out optLevel, out optName);
var mreqn = new Interop.libc.ip_mreqn {
imr_multiaddr = new Interop.libc.in_addr {
s_addr = unchecked((uint)optionValue.Group.GetAddress())
}
};
if (optionValue.LocalAddress != null)
{
mreqn.imr_address.s_addr = unchecked((uint)optionValue.LocalAddress.GetAddress());
}
else
{
// TODO: what is the endianness of ipv6mr_ifindex?
mreqn.imr_ifindex = optionValue.InterfaceIndex;
}
int err = Interop.libc.setsockopt(handle.FileDescriptor, optLevel, optName, &mreqn, (uint)sizeof(Interop.libc.ip_mreqn));
return err == -1 ? GetLastSocketError() : SocketError.Success;
}
