Code
Imports System.Collections.Generic
Imports System.Net
Imports System.Net.Sockets
Imports System.Runtime.Serialization
Imports System.Text
Namespace Socks5Client
Public Class Socks5Client
Private _socksAddr As String
Private _socksPort As Integer
Private _destAddr As String
Private _destPort As Integer
Private _username As String
Private _password As String
Private _socket As Socket
Private Const SOCKS_VER As Integer = &H5
Private Const AUTH_METH_SUPPORT As Integer = &H2
Private Const USER_PASS_AUTH As Integer = &H2
Private Const NOAUTH As Integer = &H0
Private Const CMD_CONNECT As Integer = &H1
Private Const SOCKS_ADDR_TYPE_IPV4 As Integer = &H1
Private Const SOCKS_ADDR_TYPE_IPV6 As Integer = &H4
Private Const SOCKS_ADDR_TYPE_DOMAIN_NAME As Integer = &H3
Private Const AUTH_METHOD_NOT_SUPPORTED As Integer = &HFF
Private Const SOCKS_CMD_SUCCSESS As Integer = &H0
Private Sub New(socksAddress As String, socksPort As Integer, destAddress As String, destPort As Integer, username As String, password As String)
_socksAddr = socksAddress
_socksPort = socksPort
_destAddr = destAddress
_destPort = destPort
_username = username
_password = password
_socket = New Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp)
End Sub
Public Function Connect() As Socket
_socket.Connect(_socksAddr, _socksPort)
Dim buffer As Byte() = New Byte(3) {}
buffer(0) = SOCKS_VER
buffer(1) = AUTH_METH_SUPPORT
buffer(2) = NOAUTH
buffer(3) = USER_PASS_AUTH
_socket.Send(buffer)
_socket.Receive(buffer, 0, 2, SocketFlags.None)
If buffer(1) = AUTH_METHOD_NOT_SUPPORTED Then
_socket.Close()
Throw New SocksAuthException()
End If
If buffer(1) = USER_PASS_AUTH AndAlso (_username Is Nothing OrElse _password Is Nothing) Then
Throw New ArgumentException("No username or password provided")
End If
If buffer(1) = USER_PASS_AUTH Then
Dim credentials As Byte() = New Byte(_username.Length + _password.Length + 2) {}
credentials(0) = 1
credentials(1) = CByte(_username.Length)
Encoding.ASCII.GetBytes(_username).CopyTo(credentials, 2)
credentials(_username.Length + 2) = CByte(_password.Length)
Encoding.ASCII.GetBytes(_password).CopyTo(credentials, _username.Length + 3)
_socket.Send(credentials, credentials.Length, SocketFlags.None)
buffer = New Byte(1) {}
_socket.Receive(buffer, buffer.Length, SocketFlags.None)
If buffer(1) <> SOCKS_CMD_SUCCSESS Then
Throw New SocksRefuseException("Username or password invalid")
End If
End If
Dim addrType As Byte = GetAddressType()
Dim address As Byte() = GetDestAddressBytes(addrType, _destAddr)
Dim port As Byte() = GetDestPortBytes(_destPort)
buffer = New Byte(4 + port.Length + (address.Length - 1)) {}
buffer(0) = SOCKS_VER
buffer(1) = CMD_CONNECT
buffer(2) = &H0
'reserved
buffer(3) = addrType
address.CopyTo(buffer, 4)
port.CopyTo(buffer, 4 + address.Length)
_socket.Send(buffer)
buffer = New Byte(254) {}
_socket.Receive(buffer, buffer.Length, SocketFlags.None)
If buffer(1) = SOCKS_CMD_SUCCSESS Then
Return _socket
End If
Throw New SocksRefuseException()
End Function
Private Function GetAddressType() As Byte
Dim ipAddr As IPAddress
Dim result As Boolean = IPAddress.TryParse(_destAddr, ipAddr)
If Not result Then
Return SOCKS_ADDR_TYPE_DOMAIN_NAME
End If
Select Case ipAddr.AddressFamily
Case AddressFamily.InterNetwork
Return SOCKS_ADDR_TYPE_IPV4
Case AddressFamily.InterNetworkV6
Return SOCKS_ADDR_TYPE_IPV6
Case Else
Throw New BadDistanationAddrException()
End Select
End Function
Private Function GetDestAddressBytes(addressType As Byte, host As String) As Byte()
Select Case addressType
Case SOCKS_ADDR_TYPE_IPV4, SOCKS_ADDR_TYPE_IPV6
Return IPAddress.Parse(host).GetAddressBytes()
Case SOCKS_ADDR_TYPE_DOMAIN_NAME
Dim bytes As Byte() = New Byte(host.Length) {}
bytes(0) = Convert.ToByte(host.Length)
Encoding.ASCII.GetBytes(host).CopyTo(bytes, 1)
Return bytes
Case Else
Return Nothing
End Select
End Function
Private Function GetDestPortBytes(value As Integer) As Byte()
Dim array As Byte() = New Byte(1) {}
array(0) = Convert.ToByte(value / 256)
array(1) = Convert.ToByte(value Mod 256)
Return array
End Function
Public Shared Function Connect(socksAddress As String, socksPort As Integer, destAddress As String, destPort As Integer, username As String, password As String) As Socket
Dim client As New Socks5Client(socksAddress, socksPort, destAddress, destPort, username, password)
Return client.Connect()
End Function
End Class
<Serializable()> _
Public Class SocksAuthException
Inherits Exception
Public Sub New()
End Sub
Public Sub New(message As String)
MyBase.New(message)
End Sub
Public Sub New(message As String, inner As Exception)
MyBase.New(message, inner)
End Sub
Protected Sub New(info As SerializationInfo, context As StreamingContext)
MyBase.New(info, context)
End Sub
End Class
<Serializable()> _
Public Class BadDistanationAddrException
Inherits Exception
Public Sub New()
End Sub
Public Sub New(message As String)
MyBase.New(message)
End Sub
Public Sub New(message As String, inner As Exception)
MyBase.New(message, inner)
End Sub
Protected Sub New(info As SerializationInfo, context As StreamingContext)
MyBase.New(info, context)
End Sub
End Class
<Serializable()> _
Public Class SocksRefuseException
Inherits Exception
Public Sub New()
End Sub
Public Sub New(message As String)
MyBase.New(message)
End Sub
Public Sub New(message As String, inner As Exception)
MyBase.New(message, inner)
End Sub
Protected Sub New(info As SerializationInfo, context As StreamingContext)
MyBase.New(info, context)
End Sub
End Class
End NamespaceEnjoy
