ipxserver.cpp

/*
 *  Copyright (C) 2002-2009  The DOSBox Team
 *  Copyright (C) 2009-2010  Michał "MasterM" Siejak
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "config.h"
#include "ipxserver.h"
#include <stdlib.h>
#include <string.h>
#include "ipx.h"

IPaddress ipxServerIp;  // IPAddress for server's listening port
UDPsocket ipxServerSocket;  // Listening server socket

packetBuffer connBuffer[SOCKETTABLESIZE];

Bit8u inBuffer[IPXBUFFERSIZE];
IPaddress ipconn[SOCKETTABLESIZE];  // Active TCP/IP connection 
UDPsocket tcpconn[SOCKETTABLESIZE];  // Active TCP/IP connections
SDLNet_SocketSet serverSocketSet;

void UnpackIP(PackedIP ipPack, IPaddress * ipAddr) {
  ipAddr->host = ipPack.host;
  ipAddr->port = ipPack.port;
}

void PackIP(IPaddress ipAddr, PackedIP *ipPack) {
  ipPack->host = ipAddr.host;
  ipPack->port = ipAddr.port;
}

Bit8u packetCRC(Bit8u *buffer, Bit16u bufSize) {
  Bit8u tmpCRC = 0;
  Bit16u i;
  for(i=0;i<bufSize;i++) {
    tmpCRC ^= *buffer;
    buffer++;
  }
  return tmpCRC;
}

static void sendIPXPacket(Bit8u *buffer, Bit16s bufSize) {
  Bit16u srcport, destport;
  Bit32u srchost, desthost;
  Bit16u i;
  Bits result;
  UDPpacket outPacket;
  outPacket.channel = -1;
  outPacket.data = buffer;
  outPacket.len = bufSize;
  outPacket.maxlen = bufSize;
  IPXHeader *tmpHeader;
  tmpHeader = (IPXHeader *)buffer;

  srchost = tmpHeader->src.addr.byIP.host;
  desthost = tmpHeader->dest.addr.byIP.host;

  srcport = tmpHeader->src.addr.byIP.port;
  destport = tmpHeader->dest.addr.byIP.port;

  // update activity timer for sending host   
  for(i=0;i<SOCKETTABLESIZE;i++) {
    if(connBuffer[i].connected && (ipconn[i].host == srchost) && (ipconn[i].port==srcport)) {
      connBuffer[i].lastused = time(NULL);
    }
  }

  if(desthost == 0xffffffff) {
    // Broadcast
    for(i=0;i<SOCKETTABLESIZE;i++) {
      if(connBuffer[i].connected && ((ipconn[i].host != srchost)||(ipconn[i].port!=srcport))) {
	outPacket.address = ipconn[i];
	result = SDLNet_UDP_Send(ipxServerSocket,-1,&outPacket);
	if(result == 0) {
	  LOG_MSG("IPXSERVER: %s", SDLNet_GetError());
	  continue;
	}
      }
    }
  } else {
    // Specific address
    for(i=0;i<SOCKETTABLESIZE;i++) {
      if((connBuffer[i].connected) && (ipconn[i].host == desthost) && (ipconn[i].port == destport)) {
	outPacket.address = ipconn[i];
	result = SDLNet_UDP_Send(ipxServerSocket,-1,&outPacket);
	if(result == 0) {
	  LOG_MSG("IPXSERVER: %s", SDLNet_GetError());
	  continue;
	}
      }
    }
  }
}

bool IPX_isConnectedToServer(Bits tableNum, IPaddress ** ptrAddr) {
  if(tableNum >= SOCKETTABLESIZE) return false;
  *ptrAddr = &ipconn[tableNum];
  return connBuffer[tableNum].connected;
}

static void ackClient(IPaddress clientAddr) {
  IPXHeader regHeader;
  UDPpacket regPacket;
  Bits result;

  SDLNet_Write16(0xffff, regHeader.checkSum);
  SDLNet_Write16(sizeof(regHeader), regHeader.length);
	
  SDLNet_Write32(0, regHeader.dest.network);
  PackIP(clientAddr, &regHeader.dest.addr.byIP);
  SDLNet_Write16(0x2, regHeader.dest.socket);

  SDLNet_Write32(1, regHeader.src.network);
  PackIP(ipxServerIp, &regHeader.src.addr.byIP);
  SDLNet_Write16(0x2, regHeader.src.socket);
  regHeader.transControl = 0;

  regPacket.data = (Uint8 *)&regHeader;
  regPacket.len = sizeof(regHeader);
  regPacket.maxlen = sizeof(regHeader);
  regPacket.address = clientAddr;
  // Send registration string to client.  If client doesn't get this, client will not be registered
  result = SDLNet_UDP_Send(ipxServerSocket,-1,&regPacket);

}

void IPX_ServerLoop() {
  UDPpacket inPacket;
  IPaddress tmpAddr;

  //char regString[] = "IPX Register\0";

  Bit16u i;
  Bit32u host;
  Bits result;

  inPacket.channel = -1;
  inPacket.data = &inBuffer[0];
  inPacket.maxlen = IPXBUFFERSIZE;


  result = SDLNet_UDP_Recv(ipxServerSocket, &inPacket);
  if (result != 0) {
    // Check to see if incoming packet is a registration packet
    // For this, I just spoofed the echo protocol packet designation 0x02
    IPXHeader *tmpHeader;
    tmpHeader = (IPXHeader *)&inBuffer[0];
	
    // Check to see if echo packet
    if(SDLNet_Read16(tmpHeader->dest.socket) == 0x2) {
      // Null destination node means its a server registration packet
      if(tmpHeader->dest.addr.byIP.host == 0x0) {
	UnpackIP(tmpHeader->src.addr.byIP, &tmpAddr);
	for(i=0;i<SOCKETTABLESIZE;i++) {
	  if((!connBuffer[i].connected) || ((time(NULL) - CONNTIMEOUT) > connBuffer[i].lastused)) {
	    // Use prefered host IP rather than the reported source IP
	    // It may be better to use the reported source
	    ipconn[i] = inPacket.address;

	    connBuffer[i].connected = true;
	    connBuffer[i].lastused = time(NULL); 
	    host = ipconn[i].host;
	    LOG_MSG("IPXSERVER: Connect from %d.%d.%d.%d", CONVIP(host));
	    ackClient(inPacket.address);
	    return;
          }
/*	  } else {
	    if((ipconn[i].host == tmpAddr.host) && (ipconn[i].port == tmpAddr.port)) {

	      LOG_MSG("IPXSERVER: Reconnect from %d.%d.%d.%d", CONVIP(tmpAddr.host));
	      // Update anonymous port number if changed
	      ipconn[i].port = inPacket.address.port;
	      ackClient(inPacket.address);
	      return;
	    }
	  }
*/					
	}
        LOG_MSG("IPXSERVER: Connection Table full.");                   
        return; 
      }
    }

    // IPX packet is complete.  Now interpret IPX header and send to respective IP address
    sendIPXPacket((Bit8u *)inPacket.data, inPacket.len);
  }
}

void IPX_StopServer() {
  SDLNet_UDP_Close(ipxServerSocket);
}

bool IPX_StartServer(Bit16u portnum) {
  Bit16u i;

  if(!SDLNet_ResolveHost(&ipxServerIp, NULL, portnum)) {
	
    ipxServerSocket = SDLNet_UDP_Open(portnum);
    if(!ipxServerSocket) return false;

    for(i=0;i<SOCKETTABLESIZE;i++) connBuffer[i].connected = false;
    return true;
  }
  return false;
}