//process incoming packet
public static bool ProcessIncomingPacket(Bytes packet, IpHeader ipHeader)
{
int offset = EthernetHeader.Size + IpHeader.Size; //14 byte ethernet header + 20 byte IP header
VTable.Assert(offset == 34);
UDPHeader udpHeader = new UDPHeader(packet, offset);
DebugPrint("ProcessIncomingPacket: Received packet from address {0} port {1}\n",
ipHeader.srcAddress.ToString(), udpHeader.srcPort);
UDP udp = GetUDPSession(udpHeader.dstPort);
//now we check to see whether the udp session wants to packet
//XXX review this logic...
//todo: check if udp is bound to local IP that dest IP matches.
//UDP header?
if ((udp != null) &&
((udp.LocalAddress == IPv4.Any) ||
(udp.RemoteAddress == ipHeader.srcAddress && udp.RemotePort == udpHeader.srcPort) ||
(udp.RemotePort == 0)))
{
offset += UDPHeader.Size;
Bytes data = Bitter.SplitOff(ref packet, offset);
//delete packet;
udp.PushPacket(data);
udp.udpWaitEvent.Set();
return(true);
}
DebugPrint("Received packe destined for inactive UDP port {0}" +
" source address {1} source port {2}\n",
udpHeader.dstPort, ipHeader.srcAddress.ToString(), udpHeader.srcPort);
//delete packet;
return(false);
}
// Original note from Yaron:
// ARP logic: see RFC 826 http://www.faqs.org/rfcs/rfc826.html
//
public void ProcessIncomingPacket(Bytes packet, IAdapter adapter)
{
//Get the ARP packet info located after the ethernet header
ArpHeader arpHeader = new ArpHeader(packet, 14);
DebugPrint("ARP: ProcessIncomingPacket\n");
//do some checks to make sure the packet is copacetic
if (arpHeader.htype != 0x1)
{
DebugPrint("ARP: ProcessIncomingPacket got wrong hardware type? 0x{0,8:x}\n",
arpHeader.htype);
//delete packet;
return;
}
if (arpHeader.ptype != 0x0800)
{
DebugPrint("ARP: ProcessIncomingPacket got wrong protocol? 0x{0,8:x}\n",
arpHeader.ptype);
//delete packet;
return;
}
//ethernet address should be 6 bytes
if (arpHeader.hlen != 6)
{
DebugPrint("ARP: ProcessIncomingPacket got wrong hw length? 0x{0,8:x}\n",
arpHeader.hlen);
//delete packet;
return;
}
if (arpHeader.plen != 4)
{
DebugPrint("ARP: ProcessIncomingPacket got wrong protocol address length? 0x{0,8:x}\n",
arpHeader.plen);
//delete packet;
return;
}
DebugPrint("Incoming packet\n");
bool merged = false;
bool updated = false;
ArpEntry target = arpTable.Lookup(arpHeader.senderIPAddr);
if (target != null && target.Dynamic == true)
{
DebugPrint("ARP UPDATE\n");
// we have it already - just update the details...
target.MacAddress = arpHeader.senderEthernetAddr;
target.EntryAge = arpTable.Age;
merged = true;
updated = true;
}
if (merged == false)
{
DebugPrint("ARP ADDITION\n");
arpTable.AddEntry(new ArpEntry(arpHeader.senderIPAddr,
arpHeader.senderEthernetAddr, true));
merged = true;
UpdatePendingRequests(arpHeader.senderIPAddr, arpHeader.senderEthernetAddr);
}
//Is this a local address
bool forSelf = IP.IsLocalAddress(arpHeader.destIPAddr);
if (forSelf == false)
{
//delete packet;
return;
}
// now figure out the opcode
if (arpHeader.op == ARP_REQUEST)
{
DebugPrint("Handling request ({0},{1}) ---> ({2},{3} \npkt dest {4} {5})\n",
arpHeader.senderIPAddr, arpHeader.senderEthernetAddr,
arpHeader.destIPAddr, adapter.HardwareAddress,
arpHeader.destIPAddr, arpHeader.destEthernetAddr
);
int dataLength = EthernetHeader.Size + ArpHeader.Size;
VTable.Assert(packet.Length >= dataLength);
Bytes data = Bitter.SplitOff(ref packet, EthernetHeader.Size);
EthernetHeader.Write(packet,
adapter.HardwareAddress,
arpHeader.senderEthernetAddr,
EthernetHeader.PROTOCOL_ARP);
//use arp header to format reply
ArpHeader.Write(data, adapter.HardwareAddress,
arpHeader.destIPAddr, ArpHeader.ARP_REPLY,
arpHeader.senderEthernetAddr, arpHeader.senderIPAddr);
adapter.PopulateTxRing(packet, data);
}
else
{
// otherwise we are done
DebugPrint(
"Handling reply ({2},{3}) <--- ({0},{1})\n",
arpHeader.senderIPAddr, arpHeader.senderEthernetAddr,
arpHeader.destIPAddr, arpHeader.destEthernetAddr
);
//delete packet;
}
if (merged && !updated)
{
DebugPrint(arpTable.ToString());
}
}