using System;
using System.IO;
using System.Collections.Generic;
using System.Text;
using System.Net;
namespace LumiSoft.Net.STUN.Message
{
/// <summary>
/// Implements STUN message. Defined in RFC 3489.
/// </summary>
public class STUN_Message
{
#region enum AttributeType
/// <summary>
/// Specifies STUN attribute type.
/// </summary>
private enum AttributeType
{
MappedAddress = 0x0001,
ResponseAddress = 0x0002,
ChangeRequest = 0x0003,
SourceAddress = 0x0004,
ChangedAddress = 0x0005,
Username = 0x0006,
Password = 0x0007,
MessageIntegrity = 0x0008,
ErrorCode = 0x0009,
UnknownAttribute = 0x000A,
ReflectedFrom = 0x000B,
XorMappedAddress = 0x8020,
XorOnly = 0x0021,
ServerName = 0x8022,
}
#endregion
#region enum IPFamily
/// <summary>
/// Specifies IP address family.
/// </summary>
private enum IPFamily
{
IPv4 = 0x01,
IPv6 = 0x02,
}
#endregion
private STUN_MessageType m_Type = STUN_MessageType.BindingRequest;
private Guid m_pTransactionID = Guid.Empty;
private IPEndPoint m_pMappedAddress = null;
private IPEndPoint m_pResponseAddress = null;
private STUN_t_ChangeRequest m_pChangeRequest = null;
private IPEndPoint m_pSourceAddress = null;
private IPEndPoint m_pChangedAddress = null;
private string m_UserName = null;
private string m_Password = null;
private STUN_t_ErrorCode m_pErrorCode = null;
private IPEndPoint m_pReflectedFrom = null;
private string m_ServerName = null;
/// <summary>
/// Default constructor.
/// </summary>
public STUN_Message()
{
m_pTransactionID = Guid.NewGuid();
}
#region method Parse
/// <summary>
/// Parses STUN message from raw data packet.
/// </summary>
/// <param name="data">Raw STUN message.</param>
public void Parse(byte[] data)
{
/* RFC 3489 11.1.
All STUN messages consist of a 20 byte header:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| STUN Message Type | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Transaction ID
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The message length is the count, in bytes, of the size of the
message, not including the 20 byte header.
*/
if(data.Length < 20){
throw new ArgumentException("Invalid STUN message value !");
}
int offset = 0;
//--- message header --------------------------------------------------
// STUN Message Type
int messageType = (data[offset++] << 8 | data[offset++]);
if(messageType == (int)STUN_MessageType.BindingErrorResponse){
m_Type = STUN_MessageType.BindingErrorResponse;
}
else if(messageType == (int)STUN_MessageType.BindingRequest){
m_Type = STUN_MessageType.BindingRequest;
}
else if(messageType == (int)STUN_MessageType.BindingResponse){
m_Type = STUN_MessageType.BindingResponse;
}
else if(messageType == (int)STUN_MessageType.SharedSecretErrorResponse){
m_Type = STUN_MessageType.SharedSecretErrorResponse;
}
else if(messageType == (int)STUN_MessageType.SharedSecretRequest){
m_Type = STUN_MessageType.SharedSecretRequest;
}
else if(messageType == (int)STUN_MessageType.SharedSecretResponse){
m_Type = STUN_MessageType.SharedSecretResponse;
}
else{
throw new ArgumentException("Invalid STUN message type value !");
}
// Message Length
int messageLength = (data[offset++] << 8 | data[offset++]);
// Transaction ID
byte[] guid = new byte[16];
Array.Copy(data,offset,guid,0,16);
m_pTransactionID = new Guid(guid);
offset += 16;
//--- Message attributes ---------------------------------------------
while((offset - 20) < messageLength){
ParseAttribute(data,ref offset);
}
}
#endregion
#region method ToByteData
/// <summary>
/// Converts this to raw STUN packet.
/// </summary>
/// <returns>Returns raw STUN packet.</returns>
public byte[] ToByteData()
{
/* RFC 3489 11.1.
All STUN messages consist of a 20 byte header:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| STUN Message Type | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Transaction ID
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The message length is the count, in bytes, of the size of the
message, not including the 20 byte header.
*/
// We allocate 512 for header, that should be more than enough.
byte[] msg = new byte[512];
int offset = 0;
//--- message header -------------------------------------
// STUN Message Type (2 bytes)
msg[offset++] = (byte)((int)this.Type >> 8);
msg[offset++] = (byte)((int)this.Type & 0xFF);
// Message Length (2 bytes) will be assigned at last.
msg[offset++] = 0;
msg[offset++] = 0;
// Transaction ID (16 bytes)
Array.Copy(m_pTransactionID.ToByteArray(),0,msg,offset,16);
offset += 16;
//--- Message attributes ------------------------------------
/* RFC 3489 11.2.
After the header are 0 or more attributes. Each attribute is TLV
encoded, with a 16 bit type, 16 bit length, and variable value:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
if(this.MappedAddress != null){
StoreEndPoint(AttributeType.MappedAddress,this.MappedAddress,msg,ref offset);
}
else if(this.ResponseAddress != null){
StoreEndPoint(AttributeType.ResponseAddress,this.ResponseAddress,msg,ref offset);
}
else if(this.ChangeRequest != null){
/*
The CHANGE-REQUEST attribute is used by the client to request that
the server use a different address and/or port when sending the
response. The attribute is 32 bits long, although only two bits (A
and B) are used:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 A B 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The meaning of the flags is:
A: This is the "change IP" flag. If true, it requests the server
to send the Binding Response with a different IP address than the
one the Binding Request was received on.
B: This is the "change port" flag. If true, it requests the
server to send the Binding Response with a different port than the
one the Binding Request was received on.
*/
// Attribute header
msg[offset++] = (int)AttributeType.ChangeRequest >> 8;
msg[offset++] = (int)AttributeType.ChangeRequest & 0xFF;
msg[offset++] = 0;
msg[offset++] = 4;
msg[offset++] = 0;
msg[offset++] = 0;
msg[offset++] = 0;
msg[offset++] = (byte)(Convert.ToInt32(this.ChangeRequest.ChangeIP) << 2 | Convert.ToInt32(this.ChangeRequest.ChangePort) << 1);
}
else if(this.SourceAddress != null){
StoreEndPoint(AttributeType.SourceAddress,this.SourceAddress,msg,ref offset);
}
else if(this.ChangedAddress != null){
StoreEndPoint(AttributeType.ChangedAddress,this.ChangedAddress,msg,ref offset);
}
else if(this.UserName != null){
byte[] userBytes = Encoding.ASCII.GetBytes(this.UserName);
// Attribute header
msg[offset++] = (int)AttributeType.Username >> 8;
msg[offset++] = (int)AttributeType.Username & 0xFF;
msg[offset++] = (byte)(userBytes.Length >> 8);
msg[offset++] = (byte)(userBytes.Length & 0xFF);
Array.Copy(userBytes,0,msg,offset,userBytes.Length);
offset += userBytes.Length;
}
else if(this.Password != null){
byte[] userBytes = Encoding.ASCII.GetBytes(this.UserName);
// Attribute header
msg[offset++] = (int)AttributeType.Password >> 8;
msg[offset++] = (int)AttributeType.Password & 0xFF;
msg[offset++] = (byte)(userBytes.Length >> 8);
msg[offset++] = (byte)(userBytes.Length & 0xFF);
Array.Copy(userBytes,0,msg,offset,userBytes.Length);
offset += userBytes.Length;
}
else if(this.ErrorCode != null){
/* 3489 11.2.9.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0 |Class| Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reason Phrase (variable) ..
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
byte[] reasonBytes = Encoding.ASCII.GetBytes(this.ErrorCode.ReasonText);
// Header
msg[offset++] = 0;
msg[offset++] = (int)AttributeType.ErrorCode;
msg[offset++] = 0;
msg[offset++] = (byte)(4 + reasonBytes.Length);
// Empty
msg[offset++] = 0;
msg[offset++] = 0;
// Class
msg[offset++] = (byte)Math.Floor((double)(this.ErrorCode.Code / 100));
// Number
msg[offset++] = (byte)(this.ErrorCode.Code & 0xFF);
// ReasonPhrase
Array.Copy(reasonBytes,msg,reasonBytes.Length);
offset += reasonBytes.Length;
}
else if(this.ReflectedFrom != null){
StoreEndPoint(AttributeType.ReflectedFrom,this.ReflectedFrom,msg,ref offset);
}
// Update Message Length. NOTE: 20 bytes header not included.
msg[2] = (byte)((offset - 20) >> 8);
msg[3] = (byte)((offset - 20) & 0xFF);
// Make reatval with actual size.
byte[] retVal = new byte[offset];
Array.Copy(msg,retVal,retVal.Length);
return retVal;
}
#endregion
#region method ParseAttribute
/// <summary>
/// Parses attribute from data.
/// </summary>
/// <param name="data">SIP message data.</param>
/// <param name="offset">Offset in data.</param>
private void ParseAttribute(byte[] data,ref int offset)
{
/* RFC 3489 11.2.
Each attribute is TLV encoded, with a 16 bit type, 16 bit length, and variable value:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value ....
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
// Type
AttributeType type = (AttributeType)(data[offset++] << 8 | data[offset++]);
// Length
int length = (data[offset++] << 8 | data[offset++]);
// MAPPED-ADDRESS
if(type == AttributeType.MappedAddress){
m_pMappedAddress = ParseEndPoint(data,ref offset);
}
// RESPONSE-ADDRESS
else if(type == AttributeType.ResponseAddress){
m_pResponseAddress = ParseEndPoint(data,ref offset);
}
// CHANGE-REQUEST
else if(type == AttributeType.ChangeRequest){
/*
The CHANGE-REQUEST attribute is used by the client to request that
the server use a different address and/or port when sending the
response. The attribute is 32 bits long, although only two bits (A
and B) are used:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 A B 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The meaning of the flags is:
A: This is the "change IP" flag. If true, it requests the server
to send the Binding Response with a different IP address than the
one the Binding Request was received on.
B: This is the "change port" flag. If true, it requests the
server to send the Binding Response with a different port than the
one the Binding Request was received on.
*/
// Skip 3 bytes
offset += 3;
m_pChangeRequest = new STUN_t_ChangeRequest((data[offset] & 4) != 0,(data[offset] & 2) != 0);
offset++;
}
// SOURCE-ADDRESS
else if(type == AttributeType.SourceAddress){
m_pSourceAddress = ParseEndPoint(data,ref offset);
}
// CHANGED-ADDRESS
else if(type == AttributeType.ChangedAddress){
m_pChangedAddress = ParseEndPoint(data,ref offset);
}
// USERNAME
else if(type == AttributeType.Username){
m_UserName = Encoding.Default.GetString(data,offset,length);
offset += length;
}
// PASSWORD
else if(type == AttributeType.Password){
m_Password = Encoding.Default.GetString(data,offset,length);
offset += length;
}
// MESSAGE-INTEGRITY
else if(type == AttributeType.MessageIntegrity){
offset += length;
}
// ERROR-CODE
else if(type == AttributeType.ErrorCode){
/* 3489 11.2.9.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0 |Class| Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reason Phrase (variable) ..
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
int errorCode = (data[offset + 2] & 0x7) * 100 + (data[offset + 3] & 0xFF);
m_pErrorCode = new STUN_t_ErrorCode(errorCode,Encoding.Default.GetString(data,offset + 4,length - 4));
offset += length;
}
// UNKNOWN-ATTRIBUTES
else if(type == AttributeType.UnknownAttribute){
offset += length;
}
// REFLECTED-FROM
else if(type == AttributeType.ReflectedFrom){
m_pReflectedFrom = ParseEndPoint(data,ref offset);
}
// XorMappedAddress
// XorOnly
// ServerName
else if(type == AttributeType.ServerName){
m_ServerName = Encoding.Default.GetString(data,offset,length);
offset += length;
}
// Unknown
else{
offset += length;
}
}
#endregion
#region method ParseEndPoint
/// <summary>
/// Pasrses IP endpoint attribute.
/// </summary>
/// <param name="data">STUN message data.</param>
/// <param name="offset">Offset in data.</param>
/// <returns>Returns parsed IP end point.</returns>
private IPEndPoint ParseEndPoint(byte[] data,ref int offset)
{
/*
It consists of an eight bit address family, and a sixteen bit
port, followed by a fixed length value representing the IP address.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x x x x x x x x| Family | Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
// Skip family
offset++;
offset++;
// Port
int port = (data[offset++] << 8 | data[offset++]);
// Address
byte[] ip = new byte[4];
ip[0] = data[offset++];
ip[1] = data[offset++];
ip[2] = data[offset++];
ip[3] = data[offset++];
return new IPEndPoint(new IPAddress(ip),port);
}
#endregion
#region method StoreEndPoint
/// <summary>
/// Stores ip end point attribute to buffer.
/// </summary>
/// <param name="type">Attribute type.</param>
/// <param name="endPoint">IP end point.</param>
/// <param name="message">Buffer where to store.</param>
/// <param name="offset">Offset in buffer.</param>
private void StoreEndPoint(AttributeType type,IPEndPoint endPoint,byte[] message,ref int offset)
{
/*
It consists of an eight bit address family, and a sixteen bit
port, followed by a fixed length value representing the IP address.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x x x x x x x x| Family | Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
// Header
message[offset++] = (byte)((int)type >> 8);
message[offset++] = (byte)((int)type & 0xFF);
message[offset++] = 0;
message[offset++] = 8;
// Unused
message[offset++] = 0;
// Family
message[offset++] = (byte)IPFamily.IPv4;
// Port
message[offset++] = (byte)(endPoint.Port >> 8);
message[offset++] = (byte)(endPoint.Port & 0xFF);
// Address
byte[] ipBytes = endPoint.Address.GetAddressBytes();
message[offset++] = ipBytes[0];
message[offset++] = ipBytes[0];
message[offset++] = ipBytes[0];
message[offset++] = ipBytes[0];
}
#endregion
#region Properties Implementation
/// <summary>
/// Gets STUN message type.
/// </summary>
public STUN_MessageType Type
{
get{ return m_Type; }
set{ m_Type = value; }
}
/// <summary>
/// Gets transaction ID.
/// </summary>
public Guid TransactionID
{
get{ return m_pTransactionID; }
}
/// <summary>
/// Gets or sets IP end point what was actually connected to STUN server. Returns null if not specified.
/// </summary>
public IPEndPoint MappedAddress
{
get{ return m_pMappedAddress; }
set{ m_pMappedAddress = value; }
}
/// <summary>
/// Gets or sets IP end point where to STUN client likes to receive response.
/// Value null means not specified.
/// </summary>
public IPEndPoint ResponseAddress
{
get{ return m_pResponseAddress; }
set{ m_pResponseAddress = value; }
}
/// <summary>
/// Gets or sets how and where STUN server must send response back to STUN client.
/// Value null means not specified.
/// </summary>
public STUN_t_ChangeRequest ChangeRequest
{
get{ return m_pChangeRequest; }
set{ m_pChangeRequest = value; }
}
/// <summary>
/// Gets or sets STUN server IP end point what sent response to STUN client. Value null
/// means not specified.
/// </summary>
public IPEndPoint SourceAddress
{
get{ return m_pSourceAddress; }
set{ m_pSourceAddress = value; }
}
/// <summary>
/// Gets or sets IP end point where STUN server will send response back to STUN client
/// if the "change IP" and "change port" flags had been set in the ChangeRequest.
/// </summary>
public IPEndPoint ChangedAddress
{
get{ return m_pChangedAddress; }
set{ m_pChangedAddress = value; }
}
/// <summary>
/// Gets or sets user name. Value null means not specified.
/// </summary>
public string UserName
{
get{ return m_UserName; }
set{ m_UserName = value; }
}
/// <summary>
/// Gets or sets password. Value null means not specified.
/// </summary>
public string Password
{
get{ return m_Password; }
set{ m_Password = value; }
}
//public MessageIntegrity
/// <summary>
/// Gets or sets error info. Returns null if not specified.
/// </summary>
public STUN_t_ErrorCode ErrorCode
{
get{ return m_pErrorCode; }
set{ m_pErrorCode = value; }
}
/// <summary>
/// Gets or sets IP endpoint from which IP end point STUN server got STUN client request.
/// Value null means not specified.
/// </summary>
public IPEndPoint ReflectedFrom
{
get{ return m_pReflectedFrom; }
set{ m_pReflectedFrom = value; }
}
/// <summary>
/// Gets or sets server name.
/// </summary>
public string ServerName
{
get{ return m_ServerName; }
set{ m_ServerName = value; }
}
#endregion
}
}
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