com.github.markusbernhardt.proxy.search.wpad.dhcp.DHCPOptions Maven / Gradle / Ivy
package com.github.markusbernhardt.proxy.search.wpad.dhcp;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
/**
* This class represents a linked list of options for a DHCP message. Its
* purpose is to ease option handling such as add, remove or change.
*
* @author Markus Bernhardt, Copyright 2016
* @author Jason Goldschmidt and Simon Frankenberger
* @author Bernd Rosstauscher, Copyright 2009
*/
public class DHCPOptions {
public static final int OPTION_PAD = 0;
public static final int OPTION_NETMASK = 1;
public static final int OPTION_TIME_OFFSET = 2;
public static final int OPTION_ROUTERS = 3;
public static final int OPTION_TIME_SERVERS = 4;
public static final int OPTION_NAME_SERVERS = 5;
public static final int OPTION_DNS_SERVERS = 6;
public static final int OPTION_LOG_SERVERS = 7;
public static final int OPTION_COOKIE_SERVERS = 8;
public static final int OPTION_LPR_SERVERS = 9;
public static final int OPTION_IMPRESS_SERVERS = 10;
public static final int OPTION_RESSOURCE_LOCATION_SERVERS = 11;
public static final int OPTION_HOSTNAME = 12;
public static final int OPTION_BOOT_FILESIZE = 13;
public static final int OPTION_MERIT_DUMPFILE = 14;
public static final int OPTION_DOMAIN_NAME = 15;
public static final int OPTION_SWAP_SERVER = 16;
public static final int OPTION_ROOT_PATH = 17;
public static final int OPTION_EXTENSIONS_PATH = 18;
public static final int OPTION_END = 255;
public static final int OPTION_IP_HOST_FORWARDING_ENABLE = 19;
public static final int OPTION_IP_HOST_NON_LOCAL_SOURCE_ROUTING_ENABLE = 20;
public static final int OPTION_IP_HOST_POLICY_FILTERS = 21;
public static final int OPTION_IP_HOST_MAXIMUM_DATAGRAM_REASSEMBLY_SIZE = 22;
public static final int OPTION_IP_HOST_DEFAULT_TTL = 23;
public static final int OPTION_IP_HOST_MTU_AGEING_TIMEOUT = 24;
public static final int OPTION_IP_HOST_MTU_PLATEAU_TABLE = 25;
public static final int OPTION_IP_INTERFACE_MTU = 26;
public static final int OPTION_IP_INTERFACE_ALL_SUBNETS_LOCAL_ENABLE = 27;
public static final int OPTION_IP_INTERFACE_BROADCAST_ADDRESS = 28;
public static final int OPTION_IP_INTERFACE_PERFORM_MASK_DISCOVERY_ENABLE = 29;
public static final int OPTION_IP_INTERFACE_MASK_SUPPLIER_ENABLE = 30;
public static final int OPTION_IP_INTERFACE_PERFORM_ROUTER_DISCOVERY_ENABLE = 31;
public static final int OPTION_IP_INTERFACE_ROUTER_SOLICITATION_ADDRESS = 32;
public static final int OPTION_IP_INTERFACE_STATIC_ROUTES = 33;
public static final int OPTION_LINK_TRAILER_ENCAPSULATION_ENABLE = 34;
public static final int OPTION_LINK_ARP_CACHE_TIMEOUT = 35;
public static final int OPTION_LINK_ETHERNET_ENCAPSULATION_ENABLE = 36;
public static final int OPTION_TCP_DEFAULT_TTL = 37;
public static final int OPTION_TCP_KEEP_ALIVE_INTERVAL = 38;
public static final int OPTION_TCP_KEEP_ALIVE_GERBAGE_ENABLE = 39;
public static final int OPTION_NIS_DOMAIN = 40;
public static final int OPTION_NIS_SERVERS = 41;
public static final int OPTION_NTP_SERVERS = 42;
public static final int OPTION_SERVICE_VENDOR_SPECIFIC_INFORMATIONS = 43;
public static final int OPTION_SERVICE_NETBOIS_NAME_SERVERS = 44;
public static final int OPTION_SERVICE_NETBOIS_DATAGRAM_DISTRIBUTION_SERVERS = 45;
public static final int OPTION_SERVICE_NETBOIS_NODE_TYPE = 46;
public static final int OPTION_SERVICE_NETBOIS_SCOPE_TYPE = 47;
public static final int OPTION_SERVICE_X_FONT_SERVERS = 48;
public static final int OPTION_SERVICE_X_DISPLAY_MANAGERS = 49;
public static final int OPTION_DHCP_IP_ADRESS_REQUESTED = 50;
public static final int OPTION_DHCP_IP_LEASE_TIME = 51;
public static final int OPTION_DHCP_OVERLOAD = 52;
public static final int OPTION_DHCP_MESSAGE_TYPE = 53;
public static final int OPTION_DHCP_SERVER_IDENTIFIER = 54;
public static final int OPTION_DHCP_PARAMETER_REQUEST_LIST = 55;
public static final int OPTION_DHCP_MESSAGE = 56;
public static final int OPTION_DHCP_MAXIMUM_MESSAGE_SIZE = 57;
public static final int OPTION_DHCP_RENEWAL_TIME = 58;
public static final int OPTION_DHCP_REBIND_TIME = 59;
public static final int OPTION_DHCP_CLASS_IDENTIFIER = 60;
public static final int OPTION_DHCP_CLIENT_IDENTIFIER = 61;
public static final int OPTION_PROXY_AUTODISCOVERY = 252;
/**
* This inner class represent an entry in the Option Table
*/
class DHCPOptionsEntry {
protected byte code;
protected byte length;
protected byte content[];
public DHCPOptionsEntry(byte entryCode, byte entryLength, byte entryContent[]) {
this.code = entryCode;
this.length = entryLength;
this.content = entryContent;
}
@Override
public String toString() {
return "Code: " + this.code + "\nContent: " + new String(this.content);
}
}
private Map optionsTable = null;
public DHCPOptions() {
this.optionsTable = new HashMap<>();
}
/**
* Removes option with specified bytecode
*
* @param entryCode
* The code of option to be removed
*/
public void removeOption(byte entryCode) {
this.optionsTable.remove(new Byte(entryCode));
}
/**
* Returns true if option code is set in list; false otherwise
*
* @param entryCode
* The node's option code
* @return true if option is set, otherwise false
*/
public boolean contains(byte entryCode) {
return this.optionsTable.containsKey(new Byte(entryCode));
}
/**
* Determines if list is empty
*
* @return true if there are no options set, otherwise false
*/
public boolean isEmpty() {
return this.optionsTable.isEmpty();
}
/**
* Fetches value of option by its option code
*
* @param entryCode
* The node's option code
* @return byte array containing the value of option entryCode. null is
* returned if option is not set.
*/
public byte[] getOption(byte entryCode) {
if (this.contains(entryCode)) {
DHCPOptionsEntry ent = this.optionsTable.get(entryCode);
return ent.content;
} else {
return null;
}
}
/**
* Changes an existing option to new value
*
* @param entryCode
* The node's option code
* @param value
* Content of node option
*/
public void setOption(byte entryCode, byte value[]) {
DHCPOptionsEntry opt = new DHCPOptionsEntry(entryCode, (byte) value.length, value);
this.optionsTable.put(new Byte(entryCode), opt);
}
/**
* Returns the option value of a specified option code in a byte array
*
* @param length
* Length of option content
* @param position
* Location in array of option node
* @param options
* The byte array of options
* @return byte array containing the value for the option
*/
private byte[] getArrayOption(int length, int position, byte options[]) {
byte value[] = new byte[length];
for (int i = 0; i < length; i++) {
value[i] = options[position + i];
}
return value;
}
/**
* Converts an options byte array to a linked list
*
* @param optionsArray
* The byte array representation of the options list
*/
public void internalize(byte[] optionsArray) {
/* Assume options valid and correct */
int pos = 4; // ignore vendor magic cookie
byte code, length;
byte value[];
while (optionsArray[pos] != (byte) 255) { // until end option
code = optionsArray[pos++];
length = optionsArray[pos++];
value = getArrayOption(length, pos, optionsArray);
setOption(code, value);
pos += length; // increment position pointer
}
}
/**
* Converts a linked options list to a byte array
*
* @return array representation of optionsTable
*/
// todo provide overflow return
public byte[] externalize() {
byte[] options = new byte[312];
options[0] = (byte) 99; // insert vendor magic cookie
options[1] = (byte) 130;
options[2] = (byte) 83;
options[3] = (byte) 99;
int position = 4;
for (Entry entry : optionsTable.entrySet()) {
options[position++] = entry.getValue().code;
options[position++] = entry.getValue().length;
for (int i = 0; i < entry.getValue().length; ++i) {
options[position++] = entry.getValue().content[i];
}
}
options[position] = (byte) 255; // insert end option
return options;
}
/**
* Prints the options linked list: For testing only.
*/
public void printList() {
System.out.println(this.optionsTable.toString());
}
}