Dhcp4java dhcpserver routine

Java code
/*
* This file is part of dhcp4java, a dhcp api for the Java language.
* (C) 2006 Stephen Hadinger
*
* This library is free software; you can redistribute it and/or
* Modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* Version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* But without any warranty; without even the implied warranty
* MERCHANTABILITY or fitness for a special PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You shoshould have written ed a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
Package org. dhcp4java. server;
 
Import static org. dhcp4java. DHCPConstants. BOOTREPLY;
Import static org. dhcp4java. DHCPConstants. DHCPACK;
Import static org. dhcp4java. DHCPConstants. DHCPOFFER;
Import static org. dhcp4java. DHCPConstants. DHO_DHCP_LEASE_TIME;
Import static org. dhcp4java. DHCPConstants. DHO_DHCP_SERVER_IDENTIFIER;
Import static org. dhcp4java. DHCPConstants. DHO_ROUTERS;
Import static org. dhcp4java. DHCPConstants. DHO_SUBNET_MASK;
Import static org. dhcp4java. DHCPConstants. HTYPE_ETHER;
 
Import java.net. InetAddress;
Import java.net. UnknownHostException;
Import java. util. HashMap;
Import java. util. Properties;
Import java. util. logging. Level;
Import java. util. logging. Logger;
 
Import org. dhcp4java. DHCPCoreServer;
Import org. dhcp4java. DHCPOption;
Import org. dhcp4java. DHCPPacket;
Import org. dhcp4java. DHCPResponseFactory;
Import org. dhcp4java. DHCPServerInitException;
Import org. dhcp4java. DHCPServlet;
 
/**
* A sample DHCP servlet (under construction ).
*
* @ Author STEPHEN an Hadinger
* @ Version 0.60
*/
Public class DHCPStaticServlet extends DHCPServlet {
 
Private static final Logger logger = Logger
. GetLogger ("org. dhcp4java. examplesserver. dhcpstaticserver ");
 
Private HashMap <String, InetAddress> macIpMap = new HashMap <String, InetAddress> ();
DHCPOption [] commonOptions;
 
/*
* (Non-Javadoc)
*
* @ See org. dhcp4java. DHCPServlet # init (java. util. Properties)
*/
@ Override
Public void init (Properties props ){
// We create a dummy packet to extract "common options"
DHCPPacket temp = new DHCPPacket ();
Try {
// Parse all properties to extract static client definitions
For (Object keyObject: props. keySet ()){
String key = (String) keyObject );
If (key. startsWith ("client .")){
String addrString = (String) props. get (keyObject );
Try {
InetAddress addr = InetAddress. getByName (addrString );
This. macIpMap. put (key. substring ("client.". length ())
. ToLowerCase (), addr );
} Catch (UnknownHostException e ){
Logger. log (Level. SEVERE, "cocould not parse InetAddress"
+ AddrString, e );
}
}
}
 
Temp. setOptionAsInetAddress (DHO_DHCP_SERVER_IDENTIFIER,
"192.168.1.1 ");
Temp. setOptionAsInt (DHO_DHCP_LEASE_TIME, 3600*24*7);/* 1 week */
Temp. setOptionAsInetAddress (DHO_SUBNET_MASK, "255.255.255.0 ");
Temp. setOptionAsInetAddress (DHO_ROUTERS, "192.168.1.1 ");
 
// Store options in a instance array
This. commonOptions = temp. getOptionsArray ();
} Catch (UnknownHostException e ){
Throw new RuntimeException (e );
}
}
 
/**
* @ See org. dhcp4java. DHCPServlet # doDiscover (org. dhcp4java. DHCPPacket)
*/
@ Override
Protected DHCPPacket doDiscover (DHCPPacket request ){
InetAddress clientIp = this. calcAddrFromMac (request );
If (clientIp = null ){
Return null;
}
 
DHCPPacket response = new DHCPPacket ();
Response. setOp (BOOTREPLY );
Response. setHtype (request. getHtype ());
Response. setHlen (request. getHlen ());
Response. setHops (byte) 0 );
Response. setXid (request. getXid ());
Response. setSecs (short) 0 );
Response. setYiaddr (clientIp );
Response. setSiaddr (server. getSockAddress (). getAddress (); // server
// Identifier
Response. setFlags (request. getFlags ());
Response. setGiaddrRaw (request. getGiaddrRaw ());
Response. setChaddr (request. getChaddr ());
 
Response. setDHCPMessageType (DHCPOFFER );
Response. setOptions (this. commonOptions );
 
Response. setAddrPort (DHCPResponseFactory. getdefasocketaddress (
Request, response. getOp ()));
 
Return response;
}
 
/**
* @ See org. dhcp4java. DHCPServlet # doRequest (org. dhcp4java. DHCPPacket)
*/
@ Override
Protected DHCPPacket doRequest (DHCPPacket request ){
InetAddress clientIp = this. calcAddrFromMac (request );
If (clientIp = null ){
Return null;
}
 
DHCPPacket response = new DHCPPacket ();
Response. setOp (BOOTREPLY );
Response. setHtype (request. getHtype ());
Response. setHlen (request. getHlen ());
Response. setHops (byte) 0 );
Response. setXid (request. getXid ());
Response. setSecs (short) 0 );
Response. setCiaddrRaw (request. getCiaddrRaw ());
Response. setYiaddr (clientIp );
Response. setSiaddr (server. getSockAddress (). getAddress (); // server
// Identifier
Response. setFlags (request. getFlags ());
Response. setGiaddrRaw (request. getGiaddrRaw ());
Response. setChaddr (request. getChaddr ());
 
Response. setDHCPMessageType (DHCPACK );
Response. setOptions (this. commonOptions );
 
Response. setAddrPort (DHCPResponseFactory. getdefasocketaddress (
Request, response. getOp ()));
 
Return response;
}
 
/**
* @ See org. dhcp4java. DHCPServlet # doDecline (org. dhcp4java. DHCPPacket)
*/
@ Override
Protected DHCPPacket doDecline (DHCPPacket request ){
Logger. warning ("DHCPDECLINE received:" + request. toString ());
Return null;
}
 
/**
* @ See org. dhcp4java. DHCPServlet # dorelbench (org. dhcp4java. DHCPPacket)
*/
@ Override
Protected DHCPPacket dorel.pdf (DHCPPacket request ){
Logger.info ("DHCPRELEASE received:" + request. toString ());
Return null;
}
 
/**
* Calculate address from packet and @ MAC Address.
*
* <P>
* Also checks if this client is accepted (Vendor, User ...)
*
* @ Param request
* @ Return address for client, or null if ignore
*/
Private InetAddress calcAddrFromMac (DHCPPacket request ){
// Check @ MAC address format
If (request. getHtype ()! = HTYPE_ETHER) & (request. getHlen ()! = 6 )){
Return null;
}
 
// Look for map
InetAddress clientIp = this. macIpMap. get (request. getChaddrAsHex ()
. ToLowerCase ());
If (clientIp = null ){
Return null; // not found
}
 
Return clientIp;
}
 
/**
* Server launcher.
*
* @ Param args
* Command line arguments-ignored
*/
Public static void main (String [] args ){
Try {
DHCPCoreServer server = DHCPCoreServer. initServer (
New DHCPStaticServlet (), null );
Logger. setLevel (Level. ALL );
New Thread (server). start ();
} Catch (DHCPServerInitException e ){
Logger. log (Level. SEVERE, "Server init", e );
}
}
}

Author: "Embedded Java & C"