private boolean sendMessage(
String status, DHCPMessage outMessage, DHCPSocket socket, int xid, int type) {
outMessage.setOp((byte) 1);
outMessage.setHtype((byte) 1);
outMessage.setHlen((byte) 6);
outMessage.setHops((byte) 0);
outMessage.setXid(xid);
outMessage.setSecs((short) 0);
if (type == 1 || type == 3) {
outMessage.setFlags((short) -32768);
} else {
outMessage.setFlags((short) 0);
}
byte initAddr[] = new byte[4];
for (int i = 0; i < 4; i++) initAddr[i] = 0;
outMessage.setCiaddr(initAddr);
outMessage.setYiaddr(initAddr);
outMessage.setSiaddr(initAddr);
outMessage.setGiaddr(initAddr);
byte mtype[] = new byte[1];
mtype[0] = (byte) type;
outMessage.setOption(53, mtype);
outMessage.setOption(51, intToBytes(1));
try {
socket.send(outMessage);
} catch (IOException ie) {
status = ie.getMessage();
return false;
}
return true;
}
/**
* Returns a DHCP DISCOVER, INFORM, or REQUEST message that can be sent to the DHCP server. DHCP
* server should respond with a DHCP OFFER, ACK, or NAK message in response..
*
* @param (InetAddress) addr The address to poll
* @param (byte) mType The type of DHCP message to send (DISCOVER, INFORM, or REQUEST)
* @return The message to send to the DHCP server.
*/
private static Message getPollingRequest(InetAddress addr, byte mType) {
int xid = 0;
synchronized (Poller.class) {
xid = ++m_nextXid;
}
DHCPMessage messageOut = new DHCPMessage();
byte[] rawIp = addr.getAddress();
// if targetOffset = true, we don't want to REQUEST the DHCP server's
// own IP, so change it by 1, trying to avoid the subnet address
// and the broadcast address.
if (targetOffset) {
if (rawIp[3] % 2 == 0 && rawIp[3] != 0) {
--rawIp[3];
} else {
++rawIp[3];
}
}
// fill DHCPMessage object
//
messageOut.setOp((byte) 1);
messageOut.setHtype((byte) 1);
messageOut.setHlen((byte) 6);
messageOut.setXid(xid);
messageOut.setSecs((short) 0);
messageOut.setChaddr(s_hwAddress); // set hardware address
if (relayMode) {
messageOut.setHops((byte) 1);
messageOut.setGiaddr(s_myIpAddress); // set relay address for replies
} else {
messageOut.setHops((byte) 0);
messageOut.setFlags(BROADCAST_FLAG);
}
messageOut.setOption(MESSAGE_TYPE, new byte[] {mType});
if (mType == DHCPMessage.REQUEST) {
if (reqTargetIp) {
messageOut.setOption(REQUESTED_IP, rawIp);
messageOut.setCiaddr(rawIp);
} else {
messageOut.setOption(REQUESTED_IP, s_requestIpAddress);
messageOut.setCiaddr(s_requestIpAddress);
}
}
if (mType == DHCPMessage.INFORM) {
messageOut.setOption(REQUESTED_IP, s_myIpAddress);
messageOut.setCiaddr(s_myIpAddress);
}
return new Message(addr, messageOut);
}