@Override
public <T> DatagramChannel setOption(SocketOption<T> name, T value) throws IOException {
if (name == null) throw new NullPointerException();
if (!supportedOptions().contains(name))
throw new UnsupportedOperationException("'" + name + "' not supported");
synchronized (stateLock) {
ensureOpen();
if (name == StandardSocketOptions.IP_TOS) {
// IPv4 only; no-op for IPv6
if (family == StandardProtocolFamily.INET) {
Net.setSocketOption(fd, family, name, value);
}
return this;
}
if (name == StandardSocketOptions.IP_MULTICAST_TTL
|| name == StandardSocketOptions.IP_MULTICAST_LOOP) {
// options are protocol dependent
Net.setSocketOption(fd, family, name, value);
return this;
}
if (name == StandardSocketOptions.IP_MULTICAST_IF) {
if (value == null)
throw new IllegalArgumentException("Cannot set IP_MULTICAST_IF to 'null'");
NetworkInterface interf = (NetworkInterface) value;
if (family == StandardProtocolFamily.INET6) {
int index = interf.getIndex();
if (index == -1) throw new IOException("Network interface cannot be identified");
Net.setInterface6(fd, index);
} else {
// need IPv4 address to identify interface
Inet4Address target = Net.anyInet4Address(interf);
if (target == null) throw new IOException("Network interface not configured for IPv4");
int targetAddress = Net.inet4AsInt(target);
Net.setInterface4(fd, targetAddress);
}
return this;
}
// remaining options don't need any special handling
Net.setSocketOption(fd, Net.UNSPEC, name, value);
return this;
}
}
