Engine Code: "DSL" Fix 3.0

[Baker]

Using the base Quake source as an example:

Open net_wins.c:

Step 1: Above "void WINS_GetLocalAddress()", add this:

int WINS_iptype(unsigned long ipaddr) {
	// Baker: 3.99e - workaround for mostly DSL/dialup

	// Return 1 if unresolvable/invalid
	// Return 2 if private network (router, LAN, whatever)
	// Return 3 if internet ip

	// TCP/IP addresses reserved for 'private' networks are:
	//10.0.0.0       to     10.255.255.255
	//172.16.0.0     to     172.31.255.255
	//192.168.0.0    to     192.168.255.255
	//
	//and as of July 2001
	//
	//169.254.0.0    to     169.254.255.255 rfc

	if (((ipaddr >> 24) & 0xff) == 0)
		return 1;  // Invalid ip

	if (((ipaddr >> 24) & 0xff) == 169 && ((ipaddr >> 16) & 0xff) == 254)
		return 1;  // Unresolvable private ip

	if (((ipaddr >> 24) & 0xff) == 10)
		return 2;  // Private ip

	if (((ipaddr >> 24) & 0xff) == 172 && ((ipaddr >> 16) & 0xff) >= 16 && ((ipaddr >> 16) & 0xff) <= 31)
		return 2;  // Private ip

	if (((ipaddr >> 24) & 0xff) == 192 && ((ipaddr >> 16) & 0xff) == 168)
		return 2;  // Private ip

	return 3;

}

Step #2: Find the "void WINS_GetLocalAddress()" procedure and replace the full procedure with the following:

void WINS_GetLocalAddress()
{
	struct hostent	*local = NULL;
	char			buff[MAXHOSTNAMELEN];
	unsigned long	addr;

	if (myAddr != INADDR_ANY)
		return;

	if (pgethostname(buff, MAXHOSTNAMELEN) == SOCKET_ERROR)
		return;

	blocktime = Sys_DoubleTime();
	WSASetBlockingHook(BlockingHook);
	local = pgethostbyname(buff);
	WSAUnhookBlockingHook();
	if (local == NULL)
		return;

	if (COM_CheckParm("-oldnet") || isDedicated) {
		// Baker: screens for unresolvable ips like 169.254.x.x (dsl modem at best, unresponsive device at worst)

		myAddr = *(int *)local->h_addr_list[0];
		addr = ntohl(myAddr);
		sprintf(my_tcpip_address, "%d.%d.%d.%d", (addr >> 24) & 0xff, (addr >> 16) & 0xff, (addr >> 8) & 0xff, addr & 0xff);

		// Baker: is ip address #0 = 169.254.x.x ?
		if (WINS_iptype(addr) == 1) {
			// Unresolvable private IP or invalid ip
			Con_DPrintf ("WINS_GetLocalAddress: ip address #0 (%s) is invalid, checking next ...\n", my_tcpip_address);

			if (local->h_addr_list[1]) {
				// ip address #1 exists, use it.
				myAddr = *(int *)local->h_addr_list[1];
				addr = ntohl(myAddr);
				sprintf(my_tcpip_address, "%d.%d.%d.%d", (addr >> 24) & 0xff, (addr >> 16) & 0xff, (addr >> 8) & 0xff, addr & 0xff);
				Con_DPrintf ("WINS_GetLocalAddress: ip address #1 (%s) found.  Using.\n", my_tcpip_address);
			} else {
				Con_DPrintf("WINS_GetLocalAddress: ip address #1 does not exist\n");
				Con_DPrintf("WINS_GetLocalAddress: Warning continuing with #0\n");
				Con_Printf("Invalid IP (%s): Is internet/network connected?\n", my_tcpip_address);
			}
		}

		return;
	}

	// Baker 3.99e: New: use internet ip over private network ip over unresolvable/invalid ip

	{
		unsigned long	addr0, addr1, addr2;
		int				choice = 0, addrtype0 = 0, addrtype1 = 0, addrtype2 = 0;
		char			tcpip0[NET_NAMELEN];
		char			tcpip1[NET_NAMELEN];
		char			tcpip2[NET_NAMELEN];

		// Baker: get ip addresses

		myAddr = *(int *)local->h_addr_list[0];
		addr0 = ntohl(myAddr);

		addrtype0 = WINS_iptype(addr0);
		sprintf(tcpip0, "%d.%d.%d.%d", (addr0 >> 24) & 0xff, (addr0 >> 16) & 0xff, (addr0 >> 8) & 0xff, addr0 & 0xff);

		if (local->h_addr_list[1]) {

			Con_Printf("\nMultiple IPs found\n%s", Con_Quakebar(36));
			Con_Printf("ip #0: %s %s\n", ((addrtype0 == 3) ? "internet     " : ((addrtype0 == 2) ? "local network" : ((addrtype0 == 1) ? "unresolvable " : "no device    "))), tcpip0);

			myAddr = *(int *)local->h_addr_list[1];
			addr1 = ntohl(myAddr);
			addrtype1 = WINS_iptype(addr1);
			sprintf(tcpip1, "%d.%d.%d.%d", (addr1 >> 24) & 0xff, (addr1 >> 16) & 0xff, (addr1 >> 8) & 0xff, addr1 & 0xff);
			Con_Printf("ip #1: %s %s\n", ((addrtype1 == 3) ? "internet     " : ((addrtype1 == 2) ? "local network" : ((addrtype1 == 1) ? "unresolvable " : "no device    "))), tcpip1);

			if (addrtype1 >= addrtype0)
				choice = 1;

			if (local->h_addr_list[2]) {

				myAddr = *(int *)local->h_addr_list[2];
				addr2 = ntohl(myAddr);
				addrtype2 = WINS_iptype(addr2);
				sprintf(tcpip2, "%d.%d.%d.%d", (addr2 >> 24) & 0xff, (addr2 >> 16) & 0xff, (addr2 >> 8) & 0xff, addr2 & 0xff);
				Con_Printf("ip #2: %s %s\n", ((addrtype2 == 3) ? "internet     " : ((addrtype2 == 2) ? "local network" : ((addrtype2 == 1) ? "unresolvable " : "no device    "))), tcpip2);

				if (addrtype2 >= (choice == 0 ? addrtype0 : addrtype1))
					choice = 2; // else the above stands
			}

			myAddr = *(int *)local->h_addr_list[choice];
			addr = ntohl(myAddr);
			sprintf(my_tcpip_address, "%d.%d.%d.%d", (addr >> 24) & 0xff, (addr >> 16) & 0xff, (addr >> 8) & 0xff, addr & 0xff);
			Con_Printf("%s", Con_Quakebar(36));
			Con_Printf("Using ip %s\n", my_tcpip_address);
			Con_Printf("%s\n", Con_Quakebar(36));
		} else {
			myAddr = *(int *)local->h_addr_list[0];
			addr = ntohl(myAddr);
			sprintf(my_tcpip_address, "%d.%d.%d.%d", (addr >> 24) & 0xff, (addr >> 16) & 0xff, (addr >> 8) & 0xff, addr & 0xff);
		}
	}

}

FAQ about the above:

#1 What is the difference between the previous DSL fix and this?

It was missing an important "else" condition.

#2 What is the "DSL" fix?

There are a number of situations where Quake can't use the internet because it tries to use the wrong IP address. This is particularly a problem for DSL without a router and for DSL when the router isn't doing the PPPOE authentication itself. It can also affect dialup + LAN or even in rare circumstances cable with some network setups.

The result is that with this fix, Quake will figure out which IP address represents the current internet connection.