/** Block datagrams from given source if a memory to receive all datagrams. */
void block(MembershipKeyImpl key, InetAddress source) throws IOException {
assert key.channel() == this;
assert key.sourceAddress() == null;
synchronized (stateLock) {
if (!key.isValid()) throw new IllegalStateException("key is no longer valid");
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() != key.group().getClass())
throw new IllegalArgumentException("Source address is different type to group");
int n;
if (key instanceof MembershipKeyImpl.Type6) {
MembershipKeyImpl.Type6 key6 = (MembershipKeyImpl.Type6) key;
n = Net.block6(fd, key6.groupAddress(), key6.index(), Net.inet6AsByteArray(source));
} else {
MembershipKeyImpl.Type4 key4 = (MembershipKeyImpl.Type4) key;
n = Net.block4(fd, key4.groupAddress(), key4.interfaceAddress(), Net.inet4AsInt(source));
}
if (n == IOStatus.UNAVAILABLE) {
// ancient kernel
throw new UnsupportedOperationException();
}
}
}
/** 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;
}
}