public override void Decode(ByteBuffer buf)
{
int len = base.DecodeLength(buf);
// since the linkAddr of the relay message is the interface
// on which the relay itself received the message to be forwarded
// we can assume that address is logically a server port
IPEndPoint relayMsgLocalAddr =
new IPEndPoint(relayMessage.GetLinkAddress(),
DhcpConstants.V6_SERVER_PORT);
// the peerAddr of the relay message is the source address of
// the message which it received and is forwarding, thus the
// peerAddress is either another relay or the client itself,
// so we don't really know what port to logically set for the
// inner message's remote port
IPEndPoint relayMsgRemoteAddr =
new IPEndPoint(relayMessage.GetPeerAddress(), 0);
// create a new buffer that will hold just this RelayOption
byte[] b = buf.getBytes(len);
ByteBuffer _buf = ByteBuffer.allocate(len);
_buf.put(b);
// use the wrapped buffer which represents the contents of the message
// contained within this relay option, but not any more, i.e. not beyond
// what _this_ relay option reports its length to be
dhcpMessage = DhcpV6Message.Decode(_buf, relayMsgLocalAddr.Address, relayMsgRemoteAddr);
}
private static DhcpV6RelayMessage HandleRelayForward(DhcpV6RelayMessage relayMessage)
{
IPAddress linkAddr = relayMessage.GetLinkAddress();
_log.Info(("Handling relay forward on link address: " + linkAddr.ToString()));
DhcpV6RelayOption relayOption = relayMessage.GetRelayOption();
if ((relayOption != null))
{
DhcpV6Message relayOptionMessage = relayOption.GetDhcpMessage();
while ((relayOptionMessage != null))
{
// check what kind of message is in the option
if ((relayOptionMessage is DhcpV6RelayMessage))
{
// encapsulated message is another relay message
DhcpV6RelayMessage anotherRelayMessage = ((DhcpV6RelayMessage)(relayOptionMessage));
// flip this inner relay_forward into a relay_reply,
// because we reuse the relay message "stack" for the reply
anotherRelayMessage.SetMessageType(DhcpConstants.V6MESSAGE_TYPE_RELAY_REPL);
// reset the client link reference
linkAddr = anotherRelayMessage.GetLinkAddress();
// reset the current relay option reference to the
// encapsulated relay message's relay option
relayOption = anotherRelayMessage.GetRelayOption();
// reset the relayOptionMessage reference to recurse
relayOptionMessage = relayOption.GetDhcpMessage();
}
else
{
// we've peeled off all the layers of the relay message(s),
// so now go handle the client request
_log.Info(("Handling client request on remote client link address: " + linkAddr.ToString()));
DhcpV6Message replyMessage = DhcpV6MessageHandler.HandleClientRequest(linkAddr, relayOptionMessage, null);
if ((replyMessage != null))
{
// replace the original client request message inside
// the relayed message with the generated Reply message
relayOption.SetDhcpMessage(replyMessage);
// flip the outer-most relay_foward into a relay_reply
relayMessage.SetMessageType(DhcpConstants.V6MESSAGE_TYPE_RELAY_REPL);
// return the relay message we started with,
// with each relay "layer" flipped from a relay_forward
// to a relay_reply, and the lowest level relayOption
// will contain our Reply for the client request
return(relayMessage);
}
relayOptionMessage = null;
// done with relayed messages
}
}
}
else
{
_log.Error("Relay message does not contain a relay option");
}
// if we get here, no reply was generated
return(null);
}
