373 lines
14 KiB
C#
373 lines
14 KiB
C#
// ----------------------------------------------------------------------------
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//
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// ----------------------------------------------------------------------------
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///
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// Microsoft Research, Cambridge
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//
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// #define DEBUG_IP
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using NetStack.Common;
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using System;
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using System.Collections;
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using System.Diagnostics;
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using System.Net.IP;
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using Drivers.Net;
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using NetStack.NetDrivers;
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using NetStack.Protocols;
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using Microsoft.Singularity;
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namespace NetStack.Runtime
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{
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///
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// This module implements the IP protocol
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// NOTICE: FOR NOW WE DO NOT HANDLE FRAGMENTATION!!!!!!!!!!!!!!
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//
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public class IPModule : IProtocol
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{
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// the version
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protected int version;
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// the icmp protocol handle (for sending control messages)
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protected IProtocol icmp;
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protected ArpModule arp;
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// IP specific stack configuration data
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HostConfiguration hostConfig;
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private const string moduleName = "IP";
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[ Conditional("DEBUG_IP") ]
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private static void DebugPrint(string format, params object [] args)
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{
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DebugStub.Print("IPModule: {0}",
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__arglist(string.Format(format, args))
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);
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}
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// INetModule interfaces
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// ------------------------
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string INetModule.ModuleName { get { return moduleName; } }
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ushort INetModule.ModuleVersion { get { return 0x01; } } // 0.1
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// called by the runtime when
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// the protocol should be started
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public bool StartModule()
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{
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// get a ref to the icmp protocol
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icmp = Core.Instance().GetProtocolByName("ICMP");
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if (icmp == null) {
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return false;
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}
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// get a ref to the arp protocol
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arp = Core.Instance().GetProtocolByName("ARP") as ArpModule;
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if (arp == null) {
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return false;
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}
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return true;
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}
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public bool StopModule()
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{
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return true;
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}
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public bool DestroyModule()
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{
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return true;
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}
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// IProtocol interfaces
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// ------------------------
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public bool Initialize(ProtocolParams parameters)
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{
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Debug.Assert(parameters == null ||
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parameters["name"] == moduleName);
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hostConfig = new HostConfiguration();
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version = ProtocolParams.LookupInt32(parameters, "version", 4);
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bool fragment = ProtocolParams.LookupBoolean(parameters,
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"fragment",
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false);
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// save the routing protocol name, if exists
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if (version != 4 || fragment == true) {
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DebugPrint("Support only exists for V4 w/o fragments.\n");
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return false;
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}
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Core core = Core.Instance();
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core.RegisterProtocol(this);
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if (!core.packetTypes.RegisterTypeHandler(PacketTypes.IP, this)) {
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core.DeregisterProtocol(this);
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return false;
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}
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return true;
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}
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public ushort GetProtocolID()
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{
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return EthernetFormat.PROTOCOL_IP;
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}
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public Session CreateSession()
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{
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return null;
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}
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// handle incoming IP packets
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public NetStatus OnProtocolReceive(NetPacket! pkt)
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{
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IPFormat.IPHeader! ipHeader;
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if (IPFormat.ReadIPHeader(pkt, out ipHeader) == false) {
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DebugPrint("bad header\n");
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return NetStatus.Code.PROTOCOL_OK;
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}
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pkt.OverlapContext = ipHeader;
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Debug.Assert(IPFormat.IsMoreFragSet(ipHeader) == false);
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// check packet checksum
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if (IPFormat.IsCheckSumOK(ipHeader) == false) {
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DebugPrint("checksum error, dropping!\n");
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return NetStatus.Code.PROTOCOL_DROP_CHKSUM;
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}
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// check if the packet is for us...
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// TBC: for now we ignore broadcasts
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// (directed + limited bcast addresses)
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Core core = Core.Instance();
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// if its not ours but we are a gateway, we should route it.
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if (hostConfig.IsLocalAddress(ipHeader.Destination) == false &&
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ipHeader.Destination != IPv4.Broadcast)
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{
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if (hostConfig.IsRouter) {
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// Not supported for the time being.
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}
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// DebugPrint("Dropping wrong destination\n");
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return NetStatus.Code.RT_DROP_WRONG_DEST;
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}
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// we should handle it..
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IProtocol prot = core.GetProtocolFromID(ipHeader.protocol);
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if (prot == null) {
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DebugPrint("Packet drop no handler for protocol id = {0}\n",
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(ushort)ipHeader.protocol);
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return NetStatus.Code.RT_DROP_NO_HANDLER;
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}
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else {
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DebugPrint("Got packet of type {0}\n", ipHeader.protocol);
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}
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// clip the packet for the next protocol header + data
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pkt.Clip(ipHeader.totalLength - IPFormat.Size - 1);
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return prot.OnProtocolReceive(pkt);
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}
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// this method sends an IP packet. It uses the IP header
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// target address to find route and sets the packet's Mux.
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// it also sets the target and source mac addresses
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public NetStatus OnProtocolSend(NetPacket! packet)
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{
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Multiplexer mux = (Multiplexer)packet.Mux;
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if (mux != null) {
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byte[]! data = (byte[]!) packet.GetRawData();
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// Source has already resolved outbound mux. Check
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// briefly that they've put values in for ethernet headers
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// (yes, only ethernet is supported here folks)
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int dstOkay = ((int)data[0] | (int)data[1] | (int)data[2] |
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(int)data[3] | (int)data[4] | (int)data[5]);
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int srcOkay = ((int)data[6] | (int)data[7] | (int)data[8] |
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(int)data[9] | (int)data[10]| (int)data[11]);
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if (dstOkay != 0 && srcOkay != 0) {
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mux.SendBuffered(packet);
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DebugPrint("Packet sent (had mux)\n");
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return NetStatus.Code.PROTOCOL_OK;
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}
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// Invalid destination or source address. Ignore request
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// to send via specific mux.
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}
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// since we may retransmit this packet, we should
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// reset the buffer to the IP boundaries!
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packet.Clip(EthernetFormat.Size,
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packet.Length - EthernetFormat.Size - 1);
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IPFormat.IPHeader! ipHeader;
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if (IPFormat.ReadIPHeader(packet, out ipHeader) == false) {
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DebugPrint("Packet dropped error)\n");
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DebugStub.Break();
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return NetStatus.Code.PROTOCOL_DROP_ERROR;
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}
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Debug.Assert(ipHeader.Destination != IPv4.Zero);
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RouteEntry e = HostConfiguration.RoutingTable.Lookup(ipHeader.Destination);
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if (e == null) {
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DebugPrint("Packet dropped no route)\n");
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return NetStatus.Code.RT_DROP_NO_ROUTE;
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}
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// DebugPrint("{0} -> {1}\n", ipHeader.Destination, e);
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// DebugPrint("Packet source {0}\n", ipHeader.Source);
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IPv4 ifaddr = e.InterfaceAddress;
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IPv4 nexthop;
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if (e.Gateway == e.InterfaceAddress) {
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nexthop = ipHeader.Destination;
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}
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else {
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nexthop = e.Gateway;
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}
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// DebugPrint("Selected destination {0}\n", nexthop);
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IAdapter adapter = hostConfig.Bindings.GetAdapter(ifaddr);
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assert adapter != null;
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Multiplexer targetMux = Core.Instance().GetMuxForAdapter(adapter);
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assert targetMux != null;
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packet.Mux = targetMux;
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EthernetAddress localMac = adapter.HardwareAddress;
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EthernetAddress remoteMac;
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IAdapter targetAdapter = hostConfig.Bindings.GetAdapter(nexthop);
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if (targetAdapter != null) {
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remoteMac = targetAdapter.HardwareAddress;
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}
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else {
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if (arp.Lookup(nexthop, out remoteMac) == false) {
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DebugPrint("No ARP Entry for: {0}\n", nexthop);
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arp.ArpRequest(ipHeader.Source, nexthop, targetMux,
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new ArpRequestCallback(ArpResponse),
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packet, TimeSpan.FromSeconds(3));
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BlockAssociatedSession(packet);
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return NetStatus.Code.RT_RETRY_PENDING_ARP;
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}
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}
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return SendResolved(packet, targetMux, localMac, remoteMac);
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}
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private NetStatus SendResolved(NetPacket! packet,
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Multiplexer! targetMux,
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EthernetAddress localMac,
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EthernetAddress remoteMac)
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{
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// set the ethernet data
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// TBC: make the ARPModule setup the packet
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{
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Session session = packet.SessionContext as Session;
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if (session != null) {
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DebugPrint("Sending packet for {0}/{1} ({2}-->{3})\n",
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session.RemoteAddress, session.RemotePort,
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localMac, remoteMac);
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}
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else {
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DebugPrint("Sending packet to {0}\n", remoteMac);
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}
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}
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Debug.Assert(packet.IsOneChunk);
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EthernetFormat.Write((byte[]!)packet.GetRawData(), 0,
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localMac, remoteMac,
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EthernetFormat.PROTOCOL_IP);
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targetMux.SendBuffered(packet);
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return NetStatus.Code.PROTOCOL_OK;
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}
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private void ArpResponse(IPv4 address,
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EthernetAddress answer,
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object cookie)
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{
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NetPacket! packet = (NetPacket!)cookie;
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DebugPrint("Got ARP response for {0} -> {1}", address, answer);
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UnblockAssociatedSession(packet);
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if (answer != EthernetAddress.Zero) {
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Multiplexer mux = (Multiplexer!)packet.Mux;
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SendResolved(packet, mux, mux.Adapter.HardwareAddress, answer);
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Core.Instance().SignalOutboundPackets();
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}
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else {
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DebugPrint("ARP timed out for {0}", address);
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}
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}
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private void BlockAssociatedSession(NetPacket! packet)
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{
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Session! session = (!)(packet.SessionContext as Session);
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session.OutQueuePaused = true;
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DebugPrint("Blocking Session {0}\n", session.Uid);
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}
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private void UnblockAssociatedSession(NetPacket! packet)
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{
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Session! session = (!)(packet.SessionContext as Session);
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session.OutQueuePaused = false;
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DebugPrint("Unblocking session {0}\n", session.Uid);
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Core.Instance().SignalOutboundPackets(); // Kickstart
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}
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public NetStatus SetProtocolSpecific(ushort opcode, byte[]! data)
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{
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return NetStatus.Code.PROTOCOL_OK;
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}
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public NetStatus GetProtocolSpecific(ushort opcode, out byte[] data)
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{
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data = null;
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return NetStatus.Code.PROTOCOL_OK;
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}
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//
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//protected NetStatus ForwardPacket(IPFormat.IPHeader! rcvIPHeader,
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// NetPacket! packet,
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// Multiplexer targetMux)
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//{
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// Debug.Assert(packet != null && packet.IsOneChunk);
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// // TBC: this is just a preliminary imp, should
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// // consider MTUs etc.
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// byte[] data = packet.ToContiguous();
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// int start = EthernetFormat.Size;
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//
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// // decrease the ttl, if it reaches 0 discard and send
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// // ICMP message using on the source mux, otherwise forward!
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// if (--rcvIPHeader.ttl == 0) {
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// // drop it! and use icmp protocol to return error
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// // TBC: icmp.OnProtocolSend(..) // will use packetArg.Mux = source mux
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// return NetStatus.Code.RT_DROP_TTL_EXPIRED;
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// }
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// // at last, forward it already!
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// // modify the header + calc new checksum
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// IPFormat.WriteIPHeader(data, start, rcvIPHeader);
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// DebugPrint("Forwarding IP packet.\n");
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//
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// return OnProtocolSend(packet);
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//}
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//
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public HostConfiguration! HostConfiguration
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{
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get { return hostConfig; }
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}
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// ctor
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public IPModule()
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{
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}
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}
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}
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