add socks module

netlib/socks.py

@@ -0,0 +1,142 @@
+import socket
+import struct
+from array import array
+from .tcp import Address
+
+
+class SocksError(Exception):
+    def __init__(self, code, message):
+        super(SocksError, self).__init__(message)
+        self.code = code
+
+class VERSION:
+    SOCKS4 = 0x04
+    SOCKS5 = 0x05
+
+
+class CMD:
+    CONNECT = 0x01
+    BIND = 0x02
+    UDP_ASSOCIATE = 0x03
+
+
+class ATYP:
+    IPV4_ADDRESS = 0x01
+    DOMAINNAME = 0x03
+    IPV6_ADDRESS = 0x04
+
+class REP:
+    SUCCEEDED = 0x00
+    GENERAL_SOCKS_SERVER_FAILURE = 0x01
+    CONNECTION_NOT_ALLOWED_BY_RULESET = 0x02
+    NETWORK_UNREACHABLE = 0x03
+    HOST_UNREACHABLE = 0x04
+    CONNECTION_REFUSED = 0x05
+    TTL_EXPIRED = 0x06
+    COMMAND_NOT_SUPPORTED = 0x07
+    ADDRESS_TYPE_NOT_SUPPORTED = 0x08
+
+class METHOD:
+    NO_AUTHENTICATION_REQUIRED = 0x00
+    GSSAPI = 0x01
+    USERNAME_PASSWORD = 0x02
+    NO_ACCEPTABLE_METHODS = 0xFF
+
+
+class ClientGreeting(object):
+    __slots__ = ("ver", "methods")
+
+    def __init__(self, ver, methods):
+        self.ver = ver
+        self.methods = methods
+
+    @classmethod
+    def from_file(cls, f):
+        ver, nmethods = struct.unpack_from("!BB", f)
+        methods = array("B")
+        methods.fromfile(f, nmethods)
+        return cls(ver, methods)
+
+    def to_file(self, f):
+        struct.pack_into("!BB", f, 0, self.ver, len(self.methods))
+        self.methods.tofile(f)
+
+
+class ServerGreeting(object):
+    __slots__ = ("ver", "method")
+
+    def __init__(self, ver, method):
+        self.ver = ver
+        self.method = method
+
+    @classmethod
+    def from_file(cls, f):
+        ver, method = struct.unpack_from("!BB", f)
+        return cls(ver, method)
+
+    def to_file(self, f):
+        struct.pack_into("!BB", f, 0, self.ver, self.method)
+
+
+class Request(object):
+    __slots__ = ("ver", "cmd", "atyp", "dst")
+
+    def __init__(self, ver, cmd, atyp, dst):
+        self.ver = ver
+        self.cmd = cmd
+        self.atyp = atyp
+        self.dst = dst
+
+    @classmethod
+    def from_file(cls, f):
+        ver, cmd, rsv, atyp = struct.unpack_from("!BBBB", f)
+        if rsv != 0x00:
+            raise SocksError(REP.GENERAL_SOCKS_SERVER_FAILURE,
+                             "Socks Request: Invalid reserved byte: %s" % rsv)
+
+        if atyp == ATYP.IPV4_ADDRESS:
+            host = socket.inet_ntoa(f.read(4))  # We use tnoa here as ntop is not commonly available on Windows.
+            use_ipv6 = False
+        elif atyp == ATYP.IPV6_ADDRESS:
+            host = socket.inet_ntop(socket.AF_INET6, f.read(16))
+            use_ipv6 = True
+        elif atyp == ATYP.DOMAINNAME:
+            length = struct.unpack_from("!B", f)
+            host = f.read(length)
+            use_ipv6 = False
+        else:
+            raise SocksError(REP.ADDRESS_TYPE_NOT_SUPPORTED,
+                             "Socks Request: Unknown ATYP: %s" % atyp)
+
+        port = struct.unpack_from("!H", f)
+        dst = Address(host, port, use_ipv6=use_ipv6)
+        return Request(ver, cmd, atyp, dst)
+
+    def to_file(self, f):
+        raise NotImplementedError()
+
+class Reply(object):
+    __slots__ = ("ver", "rep", "atyp", "bnd")
+
+    def __init__(self, ver, rep, atyp, bnd):
+        self.ver = ver
+        self.rep = rep
+        self.atyp = atyp
+        self.bnd = bnd
+
+    @classmethod
+    def from_file(cls, f):
+        raise NotImplementedError()
+
+    def to_file(self, f):
+        struct.pack_into("!BBBB", f, 0, self.ver, self.rep, 0x00, self.atyp)
+        if self.atyp == ATYP.IPV4_ADDRESS:
+            f.write(socket.inet_aton(self.bnd.host))
+        elif self.atyp == ATYP.IPV6_ADDRESS:
+            f.write(socket.inet_pton(socket.AF_INET6, self.bnd.host))
+        elif self.atyp == ATYP.DOMAINNAME:
+            struct.pack_into("!B", f, 0, len(self.bnd.host))
+            f.write(self.bnd.host)
+        else:
+            raise SocksError(REP.ADDRESS_TYPE_NOT_SUPPORTED, "Unknown ATYP: %s" % self.atyp)
+        struct.pack_into("!H", f, 0, self.bnd.port)