/// <summary>
/// Parses an array of bytes containing every attributes of a message and
/// add them to managed and unmanaged attributes lists
/// </summary>
/// <param name="attributes">The array of byte which contains every attributes of a message</param>
private void ImportAttributes(byte[] attributes)
{
Int32 offset = 0;
Int32 attributesLength = attributes.Length;
while (offset < attributesLength)
{
// We retrieve length and add it attribute header length (4 bytes)
UInt16 valueLength = BitConverter.ToUInt16(StunUtilities.SubArray(attributes, offset + 2, 2), 0);
UInt16 attributeLength = (UInt16)(StunUtilities.ReverseBytes(valueLength) + 4);
// Adjust original length to a padded 32bit length
if (attributeLength % 4 != 0)
{
attributeLength = (UInt16)(attributeLength + (4 - attributeLength % 4));
}
StunAttribute attr = StunUtilities.SubArray(attributes, offset, attributeLength);
// When doing auto conversion of a byte array, according to STUN RFC 5389
// only the first attribute of a given type must be taken into account
this.SetAttribute(attr, false);
offset += attributeLength;
}
}
/// <summary>
/// Computes a HMAC SHA1 based on this StunMessage attributes
/// </summary>
/// <param name="hmacSha1Key">The key of HMAC SHA1 computation algorithm</param>
/// <returns>The HMAC computed value of this StunMessage</returns>
private byte[] ComputeHMAC(byte[] hmacSha1Key)
{
byte[] hashed;
using (HMACSHA1 hmacSha1 = new HMACSHA1(hmacSha1Key))
{
StunMessage thisCopy = new StunMessage(this.MethodType, this.MethodClass, this.TransactionID);
foreach (var item in this.attributesList)
{
if (item.Key == StunAttributeType.MessageIntegrity)
{
break;
}
thisCopy.SetAttribute(item.Value);
}
if (this.Stun.FingerPrint != null)
{
thisCopy.SetAttribute(this.Stun.FingerPrint);
}
byte[] thisCopyBytes = thisCopy;
// Insert a fake message length for HMAC computation as described in [RFC5489#15.4]
UInt16 dummyLength = StunUtilities.ReverseBytes((UInt16)(thisCopy.MessageLength + 24)); // 20 hmac + 4 header
BitConverter.GetBytes(dummyLength).CopyTo(thisCopyBytes, 2);
hashed = hmacSha1.ComputeHash(thisCopyBytes);
}
return(hashed);
}
/// <summary>
/// Convert a network-byte ordered array of bytes to a StunAttributeType
/// </summary>
/// <param name="bytes">An array of 2 bytes (16bits) representing an attribute type</param>
/// <returns>
/// The StunAttributeType matching the array of bytes
/// Returns StunAttributeType.Unmanaged if the byte array doesn't match any StunAttributeType StunValue's
/// </returns>
public static StunAttributeType BytesToAttributeType(byte[] bytes)
{
UInt16 type = StunUtilities.ReverseBytes(BitConverter.ToUInt16(bytes, 0));
foreach (FieldInfo field in typeof(StunAttributeType).GetFields())
{
Object[] fieldAttributes = field.GetCustomAttributes(typeof(StunValueAttribute), false);
if (fieldAttributes.Length == 1)
{
StunValueAttribute stunValueAttribute = fieldAttributes.GetValue(0) as StunValueAttribute;
if (stunValueAttribute != null &&
stunValueAttribute.Value == type)
{
return((StunAttributeType)Enum.Parse(typeof(StunAttributeType), field.Name));
}
}
}
return(StunAttributeType.Unmanaged);
}
/// <summary>
/// Sample usage of this StunClient
/// </summary>
/// <param name="args">Unused</param>
private static void Main(string[] args)
{
KeyValuePair <IPEndPoint, IPEndPoint> stunKeyValue = StunUtilities.GetMappedAddressFrom(null,
new IPEndPoint(IPAddress.Parse("66.228.45.110"), StunClient.DEFAULT_STUN_PORT),
ProtocolType.Udp);
StunMessage msg = new StunMessage(StunMethodType.Binding, StunMethodClass.Request, StunUtilities.NewTransactionId);
msg.Stun.Realm = new UTF8Attribute(StunAttributeType.Realm, "Hello World !");
msg.Stun.Username = new UTF8Attribute(StunAttributeType.Username, "Bob");
byte[] octets = msg;
StunMessage msgCopy = octets;
// Reuse of an existing local IPEndPoint makes the three requests returning
// the same MappedAddress IPEndPoint if this client is behind a Cone NAT
StunClient cli1 = new StunClient(stunKeyValue.Key,
new IPEndPoint(IPAddress.Parse("66.228.45.110"), StunClient.DEFAULT_STUNS_PORT),
ProtocolType.Tcp, null,
(sender, certificate, chain, sslPolicyErrors) => true);
// Sample TLS over TCP working with ejabberd but may not work with the sample server IP given here
cli1.Connect();
StunMessage resp1 = cli1.SendMessage(msgCopy);
cli1.Disconnect();
msgCopy.ClearAttributes();
StunClient cli2 = new StunClient(stunKeyValue.Key,
new IPEndPoint(IPAddress.Parse("132.177.123.13"), StunClient.DEFAULT_STUN_PORT),
ProtocolType.Udp, null, null);
cli2.Connect();
StunMessage resp2 = cli2.SendMessage(msgCopy);
cli2.Disconnect();
}
/// <summary>
/// TODO: Documentation RefreshAllocation
/// </summary>
/// <param name="allocation"></param>
/// <param name="lifeTime"></param>
public void RefreshAllocation(TurnAllocation allocation, UInt32 lifeTime)
{
StunMessage msg = new StunMessage(StunMethodType.Refresh, StunMethodClass.Request, StunUtilities.NewTransactionId);
msg.Stun.Username = new UTF8Attribute(StunAttributeType.Username, allocation.Username);
msg.Stun.Realm = new UTF8Attribute(StunAttributeType.Realm, allocation.Realm);
msg.Stun.Nonce = new UTF8Attribute(StunAttributeType.Nonce, allocation.Nonce);
msg.Turn.LifeTime = new StunAttribute(StunAttributeType.LifeTime, BitConverter.GetBytes(StunUtilities.ReverseBytes(lifeTime)));
msg.AddMessageIntegrity(allocation.Password, true);
this.StunClient.BeginSendMessage(msg, null);
}
/// <summary>
/// TODO: Documentation StunClient_OnReceivedSuccessResponse
/// </summary>
/// <param name="sender"></param>
/// <param name="receivedMsg"></param>
/// <param name="sentMsg"></param>
/// <param name="transactionObject"></param>
private void StunClient_OnReceivedSuccessResponse(object sender, StunMessage receivedMsg, StunMessage sentMsg, object transactionObject)
{
switch (receivedMsg.MethodType)
{
case StunMethodType.Allocate:
TurnAllocation allocation = new TurnAllocation()
{
Username = sentMsg.Stun.Username.ValueString,
Password = transactionObject as String,
Realm = sentMsg.Stun.Realm.ValueString,
Nonce = sentMsg.Stun.Nonce.ValueString,
RelayedMappedAddress = receivedMsg.Turn.XorRelayedAddress,
MappedAddress = receivedMsg.Stun.XorMappedAddress,
StartTime = DateTime.Now,
LifeTime = StunUtilities.ReverseBytes(BitConverter.ToUInt32(receivedMsg.Turn.LifeTime.Value, 0))
};
if (this.Allocations.ContainsKey(receivedMsg.Turn.XorRelayedAddress))
{
this.Allocations[receivedMsg.Turn.XorRelayedAddress] = allocation;
}
else
{
this.Allocations.Add(receivedMsg.Turn.XorRelayedAddress, allocation);
if (this.OnAllocateSucceed != null)
{
this.OnAllocateSucceed(this, allocation, sentMsg, receivedMsg);
}
}
break;
case StunMethodType.CreatePermission:
TurnPermission permission = new TurnPermission()
{
PeerAddress = sentMsg.Turn.XorPeerAddress,
StartTime = DateTime.Now,
LifeTime = 300
};
TurnAllocation permAllocation = transactionObject as TurnAllocation;
if (permAllocation.Permissions.ContainsKey(sentMsg.Turn.XorPeerAddress))
{
permAllocation.Permissions[sentMsg.Turn.XorPeerAddress] = permission;
}
else
{
permAllocation.Permissions.Add(sentMsg.Turn.XorPeerAddress, permission);
if (this.OnCreatePermissionSucceed != null)
{
this.OnCreatePermissionSucceed(this, permAllocation, permission, sentMsg, receivedMsg);
}
}
break;
case StunMethodType.ChannelBind:
TurnChannel channel = new TurnChannel()
{
Channel = sentMsg.Turn.ChannelNumber,
PeerAddress = sentMsg.Turn.XorPeerAddress,
StartTime = DateTime.Now,
LifeTime = 600
};
TurnAllocation channelAllocation = transactionObject as TurnAllocation;
if (channelAllocation.Channels.ContainsKey(sentMsg.Turn.ChannelNumber))
{
channelAllocation.Channels[sentMsg.Turn.ChannelNumber] = channel;
}
else
{
channelAllocation.Channels.Add(sentMsg.Turn.ChannelNumber, channel);
if (this.OnChannelBindSucceed != null)
{
this.OnChannelBindSucceed(this, transactionObject as TurnAllocation, channel, sentMsg, receivedMsg);
}
}
break;
case StunMethodType.ConnectionBind:
if (this.OnConnectionBindSucceed != null)
{
this.OnConnectionBindSucceed(this, transactionObject as Socket, receivedMsg);
}
break;
}
}
