SRB2/tools/SRB2Updater/ServerQuerier.cs

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C#
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2014-03-15 16:59:03 +00:00
using System;
using System.Collections.Generic;
using System.Text;
using System.Net;
using System.Net.Sockets;
using System.IO;
namespace SRB2Updater
{
class ServerQuerier
{
private UdpClient udpclient;
private IPEndPoint ipepMS;
private const int MS_HOLEPUNCH_SIZE = 0;
private const int PT_ASKINFO_SIZE = 16;
private const byte PT_ASKINFO = 12;
private const byte PT_SERVERINFO = 13;
private const int MAXSERVERNAME = 32;
private const int MAX_WADPATH = 128;
/// <summary>
/// Constructs a ServerQuerier object.
/// </summary>
public ServerQuerier()
{
udpclient = new UdpClient(0, AddressFamily.InterNetwork);
// Fix for WSAECONNRESET. Only affects Win2k and up. If I send a
// packet to a host which replies with an ICMP Port Unreachable,
// subsequent socket operations go doo-lally. So, we enable the
// older behaviour of ignoring these ICMP messages, since we don't
// care about them anyway.
if (Environment.OSVersion.Platform == PlatformID.Win32NT &&
Environment.OSVersion.Version.Major >= 5)
{
const uint IOC_IN = 0x80000000;
const uint IOC_VENDOR = 0x18000000;
const uint SIO_UDP_CONNRESET = IOC_IN | IOC_VENDOR | 12;
udpclient.Client.IOControl(unchecked((int)SIO_UDP_CONNRESET), new byte[] { Convert.ToByte(false) }, null);
}
}
public void StartListening(ServerInfoReceiveHandler sirh)
{
// Start listening.
udpclient.BeginReceive(new AsyncCallback(ServerInfoReceiveHandler.Receive), sirh);
}
/// <summary>
/// Sets the master server address. Necessary before querying via the MS.
/// </summary>
/// <param name="strAddress">IP address of hostname of MS.</param>
/// <param name="unPort">Port of MS.</param>
public void SetMasterServer(string strAddress, ushort unPort)
{
IPAddress address = Dns.GetHostEntry(strAddress).AddressList[0];
ipepMS = new IPEndPoint(address, unPort);
}
public void Query(string strAddress, ushort unPort)
{
// Build the packet.
byte[] byPacket = new byte[PT_ASKINFO_SIZE];
BinaryWriter bw = new BinaryWriter(new MemoryStream(byPacket));
bw.Seek(4, SeekOrigin.Begin); // Skip the checksum.
bw.Write((byte)0); // ack
bw.Write((byte)0); // ackreturn
bw.Write((byte)PT_ASKINFO); // Packet type.
bw.Write((byte)0); // Reserved.
bw.Write((byte)0); // Version. This is actually unnecessary -- the client will reply anyway. -MattW_CFI
bw.Write((byte)0); // Reserved.
bw.Write((byte)0); // Reserved.
bw.Write((byte)0); // Reserved.
// Time for ping calculation.
bw.Write(unchecked((uint)(DateTime.Now.Ticks / 10000)));
// Calculate the checksum.
bw.Seek(0, SeekOrigin.Begin);
bw.Write(SRB2Checksum(byPacket));
// Send the packet.
udpclient.Send(byPacket, byPacket.Length, strAddress, unPort);
}
/// <summary>
/// Calculates the checksum of an SRB2 packet.
/// </summary>
/// <param name="byPacket">Packet.</param>
/// <returns>Checksum.</returns>
private static uint SRB2Checksum(byte[] byPacket)
{
uint c = 0x1234567;
int i;
for (i = 4; i < byPacket.Length; i++)
unchecked
{
c += (uint)byPacket[i] * (uint)(i - 3);
}
return c;
}
private static string ReadFixedLengthStr(BinaryReader br, int iLen)
{
String str = Encoding.ASCII.GetString(br.ReadBytes(iLen));
int iPos = str.IndexOf("\0");
if (iPos >= 0)
str = str.Remove(iPos);
return str;
}
public abstract class ServerInfoReceiveHandler
{
UdpClient udpclient;
IPEndPoint ipepRemote;
/// <summary>
/// Called after a server info packet is received.
/// </summary>
/// <param name="srb2si">Server info.</param>
public abstract void ProcessServerInfo(SRB2ServerInfo srb2si);
public abstract void HandleException(Exception e);
public ServerInfoReceiveHandler(ServerQuerier sq)
{
ipepRemote = new IPEndPoint(IPAddress.Any, 0);
udpclient = sq.udpclient;
}
public static void Receive(IAsyncResult ar)
{
ServerInfoReceiveHandler sirh = (ServerInfoReceiveHandler)ar.AsyncState;
byte[] byPacket = sirh.udpclient.EndReceive(ar, ref sirh.ipepRemote);
// Analyse the packet.
BinaryReader br = new BinaryReader(new MemoryStream(byPacket));
// Get the checksum.
uint uiChecksum = br.ReadUInt32();
// Skip ack and ackreturn and get packet type.
br.ReadBytes(2);
byte byPacketType = br.ReadByte();
// Only interested in valid PT_SERVERINFO packets.
if (byPacketType == PT_SERVERINFO && uiChecksum == SRB2Checksum(byPacket))
{
bool bMalformed = true;
// Skip padding.
br.ReadByte();
// Remember where we are.
long iPacketStart = br.BaseStream.Position;
// Try to interpret the packet in each recognised format.
foreach (ServerInfoVer siv in Enum.GetValues(typeof(ServerInfoVer)))
{
SRB2ServerInfo srb2si;
byte byNumWads = 0;
srb2si.siv = siv;
br.BaseStream.Position = iPacketStart;
// Get address from socket.
srb2si.strAddress = sirh.ipepRemote.Address.ToString();
srb2si.unPort = unchecked((ushort)sirh.ipepRemote.Port);
// Get version.
byte byVersion = br.ReadByte();
if (siv == ServerInfoVer.SIV_PREME)
{
br.ReadBytes(3);
uint uiSubVersion = br.ReadUInt32();
// Format version.
// MattW_CFI: I hope you don't mind this exception, Oogaland, but 0.01.6 looks odd >_>
if (byVersion == 1 && uiSubVersion == 6)
srb2si.strVersion = "X.01.6";
else
srb2si.strVersion = byVersion.ToString();
//srb2si.strVersion = String.Format("{0}.{1:00}.{2}", byVersion / 100, byVersion % 100, uiSubVersion);
}
else
{
byte bySubVersion = br.ReadByte();
// Format version.
//srb2si.strVersion = String.Format("{0}.{1:00}.{2}", byVersion / 100, byVersion % 100, bySubVersion);
srb2si.strVersion = byVersion.ToString();
}
srb2si.byPlayers = br.ReadByte();
srb2si.byMaxplayers = br.ReadByte();
srb2si.byGametype = br.ReadByte();
srb2si.bModified = (br.ReadByte() != 0);
if (siv == ServerInfoVer.SIV_ME)
byNumWads = br.ReadByte();
srb2si.sbyAdminplayer = br.ReadSByte();
if (siv == ServerInfoVer.SIV_PREME)
br.ReadBytes(3);
// Calculate ping.
srb2si.uiTime = unchecked((uint)((long)(DateTime.Now.Ticks / 10000 - br.ReadUInt32()) % ((long)UInt32.MaxValue + 1)));
if (siv == ServerInfoVer.SIV_PREME)
br.ReadUInt32();
// Get and tidy map name.
if (siv == ServerInfoVer.SIV_PREME)
{
srb2si.strMapName = ReadFixedLengthStr(br, 8);
srb2si.strName = ReadFixedLengthStr(br, MAXSERVERNAME);
}
else
{
srb2si.strName = ReadFixedLengthStr(br, MAXSERVERNAME);
srb2si.strMapName = ReadFixedLengthStr(br, 8);
}
if (siv == ServerInfoVer.SIV_PREME)
byNumWads = br.ReadByte();
// Create new list of strings of initial size equal to number of wads.
srb2si.listFiles = new List<AddedWad>(byNumWads);
// Get the files info.
byte[] byFiles = br.ReadBytes(siv == ServerInfoVer.SIV_PREME ? 4096 : 936);
BinaryReader brFiles = new BinaryReader(new MemoryStream(byFiles));
// Extract the filenames.
try
{
for (int i = 0; i < byNumWads; i++)
{
bool bFullString = false;
AddedWad aw = new AddedWad();
if (siv == ServerInfoVer.SIV_PREME)
{
aw.bImportant = brFiles.ReadByte() != 0;
aw.downloadtype = (DownloadTypes)brFiles.ReadByte();
}
else
{
byte byFileStatus = brFiles.ReadByte();
aw.bImportant = (byFileStatus & 0xF) != 0;
aw.downloadtype = (DownloadTypes)(byFileStatus >> 4);
}
aw.uiSize = brFiles.ReadUInt32();
// Work out how long the string is.
int iStringPos = (int)brFiles.BaseStream.Position;
while (iStringPos < byFiles.Length && byFiles[iStringPos] != 0) iStringPos++;
// Make sure it's not longer than the max name length.
if (iStringPos - (int)brFiles.BaseStream.Position > MAX_WADPATH)
{
bFullString = true;
iStringPos = MAX_WADPATH + (int)brFiles.BaseStream.Position;
}
// Get the info and add it, if possible.
if (iStringPos > (int)brFiles.BaseStream.Position)
{
aw.strFilename = Encoding.ASCII.GetString(brFiles.ReadBytes(iStringPos - (int)brFiles.BaseStream.Position));
srb2si.listFiles.Add(aw);
}
// Skip nul.
if (!bFullString) brFiles.ReadByte();
// Skip the md5sum.
brFiles.ReadBytes(16);
}
// Okay, done! Do something useful with the server info.
sirh.ProcessServerInfo(srb2si);
// If we got this far without an exception, leave the foreach loop.
bMalformed = false;
break;
}
catch (EndOfStreamException)
{
// Packet doesn't match supposed type, so we swallow the exception
// and try remaining types.
}
catch (Exception e)
{
sirh.HandleException(e);
break;
}
}
if (bMalformed)
sirh.HandleException(new Exception("Received invalid PT_SERVERINFO packet from " + sirh.ipepRemote.Address + ":" + sirh.ipepRemote.Port + "."));
}
// Resume listening.
sirh.ipepRemote = new IPEndPoint(IPAddress.Any, 0);
sirh.udpclient.BeginReceive(new AsyncCallback(Receive), sirh);
}
}
public enum DownloadTypes
{
DT_TOOBIG = 0,
DT_OK = 1,
DT_DISABLED = 2
}
public struct AddedWad
{
public string strFilename;
public bool bImportant;
public uint uiSize;
public DownloadTypes downloadtype;
}
public enum ServerInfoVer
{
SIV_PREME,
SIV_ME
};
public struct SRB2ServerInfo
{
public string strAddress;
public ushort unPort;
public ServerInfoVer siv;
public string strVersion;
public byte byPlayers;
public byte byMaxplayers;
public byte byGametype;
public bool bModified;
public sbyte sbyAdminplayer;
public uint uiTime;
public string strMapName;
public string strName;
public List<AddedWad> listFiles;
}
}
}