- Set packet server as the default for four or more player games, and also the

default for three player games where the other players are not in the same
  private IP range.




SVN r1364 (trunk)

src/i_net.cpp

@@ -777,10 +777,64 @@ void JoinGame (int i)
 	doomcom.numplayers = doomcom.numnodes;
 }
 
+static int PrivateNetOf(in_addr in)
+{
+	int addr = ntohl(in.s_addr);
+		 if ((addr & 0xFFFF0000) == 0xC0A80000)		// 192.168.0.0
+	{
+		return 0xC0A80000;
+	}
+	else if ((addr & 0xFFF00000) == 0xAC100000)		// 172.16.0.0
+	{
+		return 0xAC100000;
+	}
+	else if ((addr & 0xFF000000) == 0x0A000000)		// 10.0.0.0
+	{
+		return 0x0A000000;
+	}
+	else if ((addr & 0xFF000000) == 0x7F000000)		// 127.0.0.0 (localhost)
+	{
+		return 0x7F000000;
+	}
+	// Not a private IP
+	return 0;
+}
+
+//
+// NodesOnSameNetwork
+//
+// The best I can really do here is check if the others are on the same
+// private network, since that means we (probably) are too.
+//
+
+static bool NodesOnSameNetwork()
+{
+	int net1;
+
+	net1 = PrivateNetOf(sendaddress[1].sin_addr);
+//	Printf("net1 = %08x\n", net1);
+	if (net1 == 0)
+	{
+		return false;
+	}
+	for (int i = 2; i < doomcom.numnodes; ++i)
+	{
+		int net = PrivateNetOf(sendaddress[i].sin_addr);
+//		Printf("Net[%d] = %08x\n", i, net);
+		if (net != net1)
+		{
+			return false;
+		}
+	}
+	return true;
+}
+
 //
 // I_InitNetwork
 //
-void I_InitNetwork (void)
+// Returns true if packet server mode might be a good idea.
+//
+bool I_InitNetwork (void)
 {
 	int i;
 	char *v;
@@ -829,8 +883,14 @@ void I_InitNetwork (void)
 		doomcom.id = DOOMCOM_ID;
 		doomcom.numplayers = doomcom.numnodes = 1;
 		doomcom.consoleplayer = 0;
-		return;
+		return false;
 	}
+	if (doomcom.numnodes < 3)
+	{ // Packet server mode with only two players is effectively the same as
+	  // peer-to-peer but with some slightly larger packets.
+		return false;
+	}
+	return doomcom.numnodes > 3 || !NodesOnSameNetwork();
 }