/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* 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 of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received 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.jnode.net.ipv4.layer;
import java.net.NoRouteToHostException;
import org.jnode.driver.ApiNotFoundException;
import org.jnode.driver.Device;
import org.jnode.driver.net.NetDeviceAPI;
import org.jnode.driver.net.NetworkException;
import org.jnode.net.HardwareAddress;
import org.jnode.net.NoSuchProtocolException;
import org.jnode.net.SocketBuffer;
import org.jnode.net.arp.ARPNetworkLayer;
import org.jnode.net.ethernet.EthernetConstants;
import org.jnode.net.ipv4.IPv4Address;
import org.jnode.net.ipv4.IPv4Constants;
import org.jnode.net.ipv4.IPv4Header;
import org.jnode.net.ipv4.IPv4ProtocolAddressInfo;
import org.jnode.net.ipv4.IPv4Route;
import org.jnode.net.ipv4.IPv4RoutingTable;
import org.jnode.net.util.NetUtils;
import org.jnode.util.TimeoutException;
/**
* @author epr
*/
public class IPv4Sender implements IPv4Constants, EthernetConstants {
/** The routing table */
private final IPv4RoutingTable rt;
/** The ARP service */
private ARPNetworkLayer arp;
/** Timeout for arp requests */
private long arpTimeout = 5000;
/** Last identification number */
private int lastId = 1;
/** My statistics */
private final IPv4Statistics stat;
/**
* Create a new instance
*
* @param ipNetworkLayer
*/
public IPv4Sender(IPv4NetworkLayer ipNetworkLayer) {
this.rt = ipNetworkLayer.getRoutingTable();
this.stat = (IPv4Statistics) ipNetworkLayer.getStatistics();
}
/**
* Transmit an IP packet. The given buffer must contain all packet data AND
* the header(s) of any IP sub-protocols, before this method is called.
*
* The following fields of the IP header must be set: tos, ttl, protocol,
* dstAddress. <p/> All other header fields are set, unless they have been
* set before. <p/> The following fields are always set (also when set
* before): version, hdrlength, identification, fragmentOffset, checksum
* <p/> If the device attribute of the skbuf has been set, the packet will
* be send to this device, otherwise a suitable route will be searched for
* in the routing table.
*
* @param hdr
* @param skbuf
* @throws NoRouteToHostException No suitable route for this packet was
* found
* @throws NetworkException The packet could not be transmitted.
*/
public void transmit(IPv4Header hdr, SocketBuffer skbuf)
throws NoRouteToHostException, NetworkException {
// Set the network layer header
skbuf.setNetworkLayerHeader(hdr);
// The destination address must have been set, check it
if (hdr.getDestination() == null) {
throw new NetworkException("The destination address must have been set");
}
stat.opackets.inc();
// The device we will use to transmit the packet
final Device dev;
final NetDeviceAPI api;
// The hardware address we will be sending to
final HardwareAddress hwDstAddr;
// Has the destination device been given?
if (skbuf.getDevice() == null) {
// The device has not been send, figure out the route ourselves.
// First lets try to find a route
final IPv4Route route;
route = findRoute(hdr, skbuf);
route.incUseCount();
// Get the device
dev = route.getDevice();
api = route.getDeviceAPI();
// Get my source address if not already set
if (hdr.getSource() == null) {
hdr.setSource(getSourceAddress(route, hdr, skbuf));
}
// Get the hardware address for this device
hwDstAddr = findDstHWAddress(route, hdr, skbuf);
} else {
// The device has been given, use it
dev = skbuf.getDevice();
try {
api = dev.getAPI(NetDeviceAPI.class);
} catch (ApiNotFoundException ex) {
throw new NetworkException("Device is not a network device", ex);
}
// The source address must have been set, check it
if (hdr.getSource() == null) {
throw new NetworkException("The source address must have been set");
}
// Find the HW destination address
hwDstAddr = findDstHWAddress(hdr.getDestination(), dev, hdr, skbuf);
}
// Set the datalength (if not set)
if (hdr.getDataLength() == 0) {
hdr.setDataLength(skbuf.getSize());
}
// Set the identification number, if not set before
if (hdr.getIdentification() == 0) {
hdr.setIdentification(getNextID());
}
// Should we fragment?
final int mtu = api.getMTU();
if (hdr.getTotalLength() <= mtu) {
// We can send the complete packet
hdr.setMoreFragments(false);
hdr.setFragmentOffset(0);
sendPacket(api, hwDstAddr, hdr, skbuf);
} else if (hdr.isDontFragment()) {
// This packet cannot be send of this device
throw new NetworkException("Packet is too large, mtu=" + mtu);
} else {
// Fragment the packet and send the fragments
fragmentPacket(api, hwDstAddr, hdr, skbuf, mtu);
}
}
/**
* Search for a route for the given buffer
*
* @param skbuf
* @return
* @throws NoRouteToHostException
*/
private IPv4Route findRoute(IPv4Header hdr, SocketBuffer skbuf) throws NoRouteToHostException {
final IPv4Address destination = hdr.getDestination();
return rt.search(destination);
}
/**
* Gets the source address to use for a given route.
*
* @param route
* @param hdr
* @param skbuf
* @return
*/
private IPv4Address getSourceAddress(IPv4Route route, IPv4Header hdr, SocketBuffer skbuf)
throws NetworkException {
final Object addrInfo = route.getDeviceAPI().getProtocolAddressInfo(ETH_P_IP);
if (addrInfo == null) {
throw new NetworkException("Source IP address not configured for device " +
route.getDevice().getId());
}
if (!(addrInfo instanceof IPv4ProtocolAddressInfo)) {
throw new NetworkException("Source IP address not valid class for device " +
route.getDevice().getId());
}
return (IPv4Address) ((IPv4ProtocolAddressInfo) addrInfo).getDefaultAddress();
}
/**
* Find the hardware address for the destination address of the given route.
*
* @param route
* @return
*/
private HardwareAddress findDstHWAddress(IPv4Route route, IPv4Header hdr, SocketBuffer skbuf)
throws NetworkException {
final ARPNetworkLayer arp = getARP();
final IPv4Address dstAddr;
if (hdr.getDestination().isBroadcast()) {
return null;
} else if (route.isGateway()) {
dstAddr = route.getGateway();
} else {
dstAddr = hdr.getDestination();
}
try {
return arp.getHardwareAddress(dstAddr, hdr.getSource(), route.getDevice(), arpTimeout);
} catch (TimeoutException ex) {
throw new NetworkException("Cannot find hardware address of " + dstAddr, ex);
}
}
/**
* Find the hardware address for the destination address of the given route.
*
* @param destination
* @param device
* @param hdr
* @param skbuf
* @return HardwareAddress
*/
private HardwareAddress findDstHWAddress(IPv4Address destination, Device device,
IPv4Header hdr, SocketBuffer skbuf) throws NetworkException {
final ARPNetworkLayer arp = getARP();
if (destination.isBroadcast()) {
return null;
} else {
try {
return arp.getHardwareAddress(destination, hdr.getSource(), device, arpTimeout);
} catch (TimeoutException ex) {
throw new NetworkException("Cannot find hardware address of " + destination, ex);
}
}
}
/**
* Insert the IP header into the buffer and send it to the device.
*
* @param api
* @param hdr
* @param skbuf
* @throws NetworkException
*/
private void sendPacket(NetDeviceAPI api, HardwareAddress dstHwAddr, IPv4Header hdr,
SocketBuffer skbuf) throws NetworkException {
skbuf.setProtocolID(ETH_P_IP);
hdr.prefixTo(skbuf);
api.transmit(skbuf, dstHwAddr);
}
/**
* Fragment the packet and send the to the device
*
* @param api
* @param hdr
* @param skbuf
* @throws NetworkException
*/
private void fragmentPacket(NetDeviceAPI api, HardwareAddress dstHwAddr, IPv4Header hdr,
SocketBuffer skbuf, int mtu) throws NetworkException {
if ((hdr.getLength() + IP_MIN_FRAG_SIZE) > mtu) {
throw new NetworkException("MTU is too small for IP, mtu=" + mtu);
}
// The complete packet
final byte[] packet = skbuf.toByteArray();
int length = packet.length;
int offset = 0;
// Size of a single fragment
final int maxFragSize = (mtu - hdr.getLength()) & ~IP_MIN_FRAG_SIZE;
// Now create the fragmented packets and send them
while (length > 0) {
final int fragLen = Math.min(maxFragSize, length);
final SocketBuffer fBuf = new SocketBuffer(packet, offset, fragLen);
hdr.setFragmentOffset(offset);
hdr.setMoreFragments((length - fragLen) > 0);
hdr.setDataLength(fragLen);
sendPacket(api, dstHwAddr, hdr, fBuf);
offset += fragLen;
length -= fragLen;
}
}
/**
* Gets the ARP service
* @return
*/
private ARPNetworkLayer getARP() throws NetworkException {
if (arp == null) {
try {
arp = (ARPNetworkLayer) NetUtils.getNLM().getNetworkLayer(
EthernetConstants.ETH_P_ARP);
} catch (NoSuchProtocolException ex) {
throw new NetworkException("Cannot find ARP layer", ex);
}
}
return arp;
}
/**
* Gets a unique identification number
* @return
*/
private synchronized int getNextID() {
lastId++;
if (lastId > 0xFFFF) {
lastId = 0;
}
return lastId;
}
}