ipv4controlblock.java

纯java操作系统jnode,安装简单和操作简单的个人使用的Java操作系统

/*
 * $Id: IPv4ControlBlock.java,v 1.2 2003/12/21 08:02:59 epr Exp $
 */
package org.jnode.net.ipv4;

import java.net.BindException;
import java.net.SocketException;

/**
 * @author Ewout Prangsma ([e-mail])
 */
public class IPv4ControlBlock {
	
	/** The list I'm a part of */
	private final IPv4ControlBlockList list;
	
	/** The local address */
	private IPv4Address lAddr;
	
	/** The local port */
	private int lPort;
	
	/** The foreign address */
	private IPv4Address fAddr;
	
	/** The foreign port */
	private int fPort;
	
	/** The protocol to use in creating IPv4 headers */
	private final int protocol;
	
	/** Type of Service to use in creating IPv4 headers */
	private final int tos;
	
	/** Time to Live to use in creating IPv4 headers */
	private final int ttl;
	
	/**
	 * Create a new instance
	 * @param list
	 * @param protocol
	 * @param ttl
	 */
	public IPv4ControlBlock(IPv4ControlBlockList list, int protocol, int ttl) {
		this.list = list;
		this.protocol = protocol;
		this.tos = 0;
		this.ttl = ttl;
		this.lAddr = IPv4Address.ANY;
		this.lPort = 0;
		this.fAddr = IPv4Address.ANY;
		this.fPort = 0;
	}

	/**
	 * @return Returns the foreign address.
	 */
	public final IPv4Address getForeignAddress() {
		return this.fAddr;
	}

	/**
	 * @return Returns the foreign port.
	 */
	public final int getForeignPort() {
		return this.fPort;
	}

	/**
	 * @return Returns the local address.
	 */
	public final IPv4Address getLocalAddress() {
		return this.lAddr;
	}

	/**
	 * @return Returns the local port.
	 */
	public final int getLocalPort() {
		return this.lPort;
	}
	
	/**
	 * Match this control block against the given parameters
	 * @param fAddr
	 * @param fPort
	 * @param lAddr
	 * @param lPort
	 * @param allowWildcards
	 * @return -1 does not match, >= 0 matches, returns number of wildcards
	 */
	final int match(IPv4Address fAddr, int fPort, IPv4Address lAddr, int lPort, boolean allowWildcards) {
		if (this.lPort != lPort) {
			// No match
			return -1;
		}
		
		int wildcard = 0;
		if (!this.lAddr.isAny()) {
			if (lAddr.isAny()) {
				wildcard++;
			} else if (!this.lAddr.equals(lAddr)) {
				// No match
				return -1;
			}
		} else {
			if (!lAddr.isAny()) {
				wildcard++;
			}
		}
		
		if (!this.fAddr.isAny()) {
			if (fAddr.isAny()) {
				wildcard++;
			} else if (!this.fAddr.equals(fAddr) || (this.fPort != fPort)) {
				// No match
				return -1;
			}
		} else {
			if (!fAddr.isAny()) {
				wildcard++;
			}
		}
		
		if (!allowWildcards && (wildcard > 0)) {
			// No wildcard match allowed
			return -1;
		}
		
		return wildcard;
	}
	
	/**
	 * Bind to a specific local address.
	 * @param lAddr
	 * @param lPort
	 */
	final void bind(IPv4Address lAddr, int lPort) 
	throws BindException {
		if ((this.lPort != 0) || !this.lAddr.isAny()) {
			throw new BindException("ControlBlock already bound");
		}
		this.lAddr = lAddr;
		this.lPort = lPort;
	}
	
	/**
	 * Connect to a foreign address.
	 * @param lAddr
	 * @param fAddr
	 * @param fPort
	 */
	public synchronized void connect(IPv4Address lAddr, IPv4Address fAddr, int fPort) {
		if (this.lAddr.isAny()) {
			if (lAddr.isAny()) {
				throw new IllegalArgumentException("Specific local address required");
			}
			this.lAddr = lAddr;
		} else if (!this.lAddr.equals(lAddr)) {
			throw new IllegalArgumentException("Different lAddr " + lAddr);
		}
		this.fAddr = fAddr;
		this.fPort = fPort;
	}

	/**
	 * Create a new control block that has the same local address and port
	 * and is connecto to the given foreign address.
	 * @param lAddr
	 * @param fAddr
	 * @param fPort
	 */
	public IPv4ControlBlock copyAndConnect(IPv4Address lAddr, IPv4Address fAddr, int fPort) 
	throws SocketException {
		final IPv4ControlBlock copy = list.createControlBlock(this);
		copy.bind(lAddr, lPort);
		copy.connect(lAddr, fAddr, fPort);
		list.add(copy);
		return copy;
	}

	/**
	 * Close any connection and remove from the control block list.
	 */
	public synchronized void removeFromList() {
		this.list.remove(this);
	}
	
	/**
	 * Create an IPv4 header for outgoing packets.
	 * This control block must have been connected before calling this method.
	 * The dataLength of the header is set to 0, this must be
	 * changes before prefixing this header to a SocketBuffer.
	 */
	protected IPv4Header createOutgoingIPv4Header() {
		return new IPv4Header(tos, ttl, protocol, fAddr, 0);
	}
	
	/**
	 * @see java.lang.Object#toString()
	 */
	public String toString() {
		return "local " + lAddr + ":" + lPort + ", foreign " + fAddr + ":" + fPort;
	}

}