private DatagramChannel connectClient() throws IOException {
final DatagramChannel client =
address.isMulticastAddress()
? DatagramChannel.open(address.getAddress().length == 4 ? INET : INET6)
: DatagramChannel.open();
final InetSocketAddress hostAddress = new InetSocketAddress(port);
client.configureBlocking(false);
if (address.isMulticastAddress()) {
client.setOption(SO_REUSEADDR, true);
client.bind(hostAddress);
if (networkInterface != null) {
// This is probably not needed, because client socket doesn't send datagrams,
// but since EVERYBODY on the internet configures this for any channels, and
// I don't see any harm this config could make, I leave it here
client.setOption(IP_MULTICAST_IF, networkInterface);
client.join(address, networkInterface);
} else {
client.join(address, NetworkInterface.getByInetAddress(hostAddress.getAddress()));
}
if (LOG.isDebugEnabled()) LOG.debug("Connecting via multicast, group=" + address);
} else {
client.bind(hostAddress);
}
if (LOG.isDebugEnabled()) LOG.debug("Listening on port " + port);
closeables.add(client);
return client;
}
@Override
@SuppressWarnings("unchecked")
public <T> T getOption(SocketOption<T> name) 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; always return 0 on IPv6
if (family == StandardProtocolFamily.INET) {
return (T) Net.getSocketOption(fd, family, name);
} else {
return (T) Integer.valueOf(0);
}
}
if (name == StandardSocketOptions.IP_MULTICAST_TTL
|| name == StandardSocketOptions.IP_MULTICAST_LOOP) {
return (T) Net.getSocketOption(fd, family, name);
}
if (name == StandardSocketOptions.IP_MULTICAST_IF) {
if (family == StandardProtocolFamily.INET) {
int address = Net.getInterface4(fd);
if (address == 0) return null; // default interface
InetAddress ia = Net.inet4FromInt(address);
NetworkInterface ni = NetworkInterface.getByInetAddress(ia);
if (ni == null) throw new IOException("Unable to map address to interface");
return (T) ni;
} else {
int index = Net.getInterface6(fd);
if (index == 0) return null; // default interface
NetworkInterface ni = NetworkInterface.getByIndex(index);
if (ni == null) throw new IOException("Unable to map index to interface");
return (T) ni;
}
}
// no special handling
return (T) Net.getSocketOption(fd, Net.UNSPEC, name);
}
}
@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;
}
}
/** Joins channel's socket to the given group/interface and optional source address. */
private MembershipKey innerJoin(InetAddress group, NetworkInterface interf, InetAddress source)
throws IOException {
if (!group.isMulticastAddress())
throw new IllegalArgumentException("Group not a multicast address");
// check multicast address is compatible with this socket
if (group instanceof Inet4Address) {
if (family == StandardProtocolFamily.INET6 && !Net.canIPv6SocketJoinIPv4Group())
throw new IllegalArgumentException("IPv6 socket cannot join IPv4 multicast group");
} else if (group instanceof Inet6Address) {
if (family != StandardProtocolFamily.INET6)
throw new IllegalArgumentException("Only IPv6 sockets can join IPv6 multicast group");
} else {
throw new IllegalArgumentException("Address type not supported");
}
// check source address
if (source != null) {
if (source.isAnyLocalAddress())
throw new IllegalArgumentException("Source address is a wildcard address");
if (source.isMulticastAddress())
throw new IllegalArgumentException("Source address is multicast address");
if (source.getClass() != group.getClass())
throw new IllegalArgumentException("Source address is different type to group");
}
SecurityManager sm = System.getSecurityManager();
if (sm != null) sm.checkMulticast(group);
synchronized (stateLock) {
if (!isOpen()) throw new ClosedChannelException();
// check the registry to see if we are already a member of the group
if (registry == null) {
registry = new MembershipRegistry();
} else {
// return existing membership key
MembershipKey key = registry.checkMembership(group, interf, source);
if (key != null) return key;
}
MembershipKeyImpl key;
if ((family == StandardProtocolFamily.INET6)
&& ((group instanceof Inet6Address) || Net.canJoin6WithIPv4Group())) {
int index = interf.getIndex();
if (index == -1) throw new IOException("Network interface cannot be identified");
// need multicast and source address as byte arrays
byte[] groupAddress = Net.inet6AsByteArray(group);
byte[] sourceAddress = (source == null) ? null : Net.inet6AsByteArray(source);
// join the group
int n = Net.join6(fd, groupAddress, index, sourceAddress);
if (n == IOStatus.UNAVAILABLE) throw new UnsupportedOperationException();
key =
new MembershipKeyImpl.Type6(
this, group, interf, source, groupAddress, index, sourceAddress);
} 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 groupAddress = Net.inet4AsInt(group);
int targetAddress = Net.inet4AsInt(target);
int sourceAddress = (source == null) ? 0 : Net.inet4AsInt(source);
// join the group
int n = Net.join4(fd, groupAddress, targetAddress, sourceAddress);
if (n == IOStatus.UNAVAILABLE) throw new UnsupportedOperationException();
key =
new MembershipKeyImpl.Type4(
this, group, interf, source, groupAddress, targetAddress, sourceAddress);
}
registry.add(key);
return key;
}
}