import socket
import struct

PROXY_TYPE_SOCKS4 = 1
PROXY_TYPE_SOCKS5 = 2
PROXY_TYPE_HTTP = 3

_defaultproxy = None
_orgsocket = socket.socket

class ProxyError(Exception):
	def __init__(self, value):
		self.value = value
	def __str__(self):
		return repr(self.value)

class GeneralProxyError(ProxyError):
	def __init__(self, value):
		self.value = value
	def __str__(self):
		return repr(self.value)

class Socks5AuthError(ProxyError):
	def __init__(self, value):
		self.value = value
	def __str__(self):
		return repr(self.value)

class Socks5Error(ProxyError):
	def __init__(self, value):
		self.value = value
	def __str__(self):
		return repr(self.value)

class Socks4Error(ProxyError):
	def __init__(self, value):
		self.value = value
	def __str__(self):
		return repr(self.value)

class HTTPError(ProxyError):
	def __init__(self, value):
		self.value = value
	def __str__(self):
		return repr(self.value)

_generalerrors = ("success",
		   "invalid data",
		   "not connected",
		   "not available",
		   "bad proxy type",
		   "bad input")

_socks5errors = ("succeeded",
		  "general SOCKS server failure",
		  "connection not allowed by ruleset",
		  "Network unreachable",
		  "Host unreachable",
		  "Connection refused",
		  "TTL expired",
		  "Command not supported",
		  "Address type not supported",
		  "Unknown error")

_socks5autherrors = ("succeeded",
		      "authentication is required",
		      "all offered authentication methods were rejected",
		      "unknown username or invalid password",
		      "unknown error")

_socks4errors = ("request granted",
		  "request rejected or failed",
		  "request rejected because SOCKS server cannot connect to identd on the client",
		  "request rejected because the client program and identd report different user-ids",
		  "unknown error")

def setdefaultproxy(proxytype=None,addr=None,port=None,rdns=True,username=None,password=None):
	"""setdefaultproxy(proxytype, addr[, port[, rdns[, username[, password]]]])
	Sets a default proxy which all further socksocket objects will use,
	unless explicitly changed.
	"""
	global _defaultproxy
	_defaultproxy = (proxytype,addr,port,rdns,username,password)

class socksocket(socket.socket):
	"""socksocket([family[, type[, proto]]]) -> socket object

	Open a SOCKS enabled socket. The parameters are the same as
	those of the standard socket init. In order for SOCKS to work,
	you must specify family=AF_INET, type=SOCK_STREAM and proto=0.
	"""

	def __init__(self, family=socket.AF_INET, type=socket.SOCK_STREAM, proto=0, _sock=None):
		_orgsocket.__init__(self,family,type,proto,_sock)
		if _defaultproxy != None:
			self.__proxy = _defaultproxy
		else:
			self.__proxy = (None, None, None, None, None, None)
		self.__proxysockname = None
		self.__proxypeername = None

	def __recvall(self, bytes):
		"""__recvall(bytes) -> data
		Receive EXACTLY the number of bytes requested from the socket.
		Blocks until the required number of bytes have been received.
		"""
		data = ""
		while len(data) < bytes:
			data = data + self.recv(bytes-len(data))
		return data

	def setproxy(self,proxytype=None,addr=None,port=None,rdns=True,username=None,password=None):
		"""setproxy(proxytype, addr[, port[, rdns[, username[, password]]]])
		Sets the proxy to be used.
		proxytype -	The type of the proxy to be used. Three types
				are supported: PROXY_TYPE_SOCKS4 (including socks4a),
				PROXY_TYPE_SOCKS5 and PROXY_TYPE_HTTP
		addr -		The address of the server (IP or DNS).
		port -		The port of the server. Defaults to 1080 for SOCKS
				servers and 8080 for HTTP proxy servers.
		rdns -		Should DNS queries be preformed on the remote side
				(rather than the local side). The default is True.
				Note: This has no effect with SOCKS4 servers.
		username -	Username to authenticate with to the server.
				The default is no authentication.
		password -	Password to authenticate with to the server.
				Only relevant when username is also provided.
		"""
		self.__proxy = (proxytype,addr,port,rdns,username,password)

	def __negotiatesocks5(self,destaddr,destport):
		"""__negotiatesocks5(self,destaddr,destport)
		Negotiates a connection through a SOCKS5 server.
		"""
		# First we'll send the authentication packages we support.
		if (self.__proxy[4]!=None) and (self.__proxy[5]!=None):
			# The username/password details were supplied to the
			# setproxy method so we support the USERNAME/PASSWORD
			# authentication (in addition to the standard none).
			self.sendall("\x05\x02\x00\x02")
		else:
			# No username/password were entered, therefore we
			# only support connections with no authentication.
			self.sendall("\x05\x01\x00")
		# We'll receive the server's response to determine which
		# method was selected
		chosenauth = self.__recvall(2)
		if chosenauth[0] != "\x05":
			self.close()
			raise GeneralProxyError((1,_generalerrors[1]))
		# Check the chosen authentication method
		if chosenauth[1] == "\x00":
			# No authentication is required
			pass
		elif chosenauth[1] == "\x02":
			# Okay, we need to perform a basic username/password
			# authentication.
			self.sendall("\x01" + chr(len(self.__proxy[4])) + self.__proxy[4] + chr(len(self.proxy[5])) + self.__proxy[5])
			authstat = self.__recvall(2)
			if authstat[0] != "\x01":
				# Bad response
				self.close()
				raise GeneralProxyError((1,_generalerrors[1]))
			if authstat[1] != "\x00":
				# Authentication failed
				self.close()
				raise Socks5AuthError,((3,_socks5autherrors[3]))
			# Authentication succeeded
		else:
			# Reaching here is always bad
			self.close()
			if chosenauth[1] == "\xFF":
				raise Socks5AuthError((2,_socks5autherrors[2]))
			else:
				raise GeneralProxyError((1,_generalerrors[1]))
		# Now we can request the actual connection
		req = "\x05\x01\x00"
		# If the given destination address is an IP address, we'll
		# use the IPv4 address request even if remote resolving was specified.
		try:
			ipaddr = socket.inet_aton(destaddr)
			req = req + "\x01" + ipaddr
		except socket.error:
			# Well it's not an IP number,  so it's probably a DNS name.
			if self.__proxy[3]==True:
				# Resolve remotely
				ipaddr = None
				req = req + "\x03" + chr(len(destaddr)) + destaddr
			else:
				# Resolve locally
				ipaddr = socket.inet_aton(socket.gethostbyname(destaddr))
				req = req + "\x01" + ipaddr
		req = req + struct.pack(">H",destport)
		self.sendall(req)
		# Get the response
		resp = self.__recvall(4)
		if resp[0] != "\x05":
			self.close()
			raise GeneralProxyError((1,_generalerrors[1]))
		elif resp[1] != "\x00":
			# Connection failed
			self.close()
			if ord(resp[1])<=8:
				raise Socks5Error(ord(resp[1]),_generalerrors[ord(resp[1])])
			else:
				raise Socks5Error(9,_generalerrors[9])
		# Get the bound address/port
		elif resp[3] == "\x01":
			boundaddr = self.__recvall(4)
		elif resp[3] == "\x03":
			resp = resp + self.recv(1)
			boundaddr = self.__recvall(resp[4])
		else:
			self.close()
			raise GeneralProxyError((1,_generalerrors[1]))
		boundport = struct.unpack(">H",self.__recvall(2))[0]
		self.__proxysockname = (boundaddr,boundport)
		if ipaddr != None:
			self.__proxypeername = (socket.inet_ntoa(ipaddr),destport)
		else:
			self.__proxypeername = (destaddr,destport)

	def getproxysockname(self):
		"""getsockname() -> address info
		Returns the bound IP address and port number at the proxy.
		"""
		return self.__proxysockname

	def getproxypeername(self):
		"""getproxypeername() -> address info
		Returns the IP and port number of the proxy.
		"""
		return _orgsocket.getpeername(self)

	def getpeername(self):
		"""getpeername() -> address info
		Returns the IP address and port number of the destination
		machine (note: getproxypeername returns the proxy)
		"""
		return self.__proxypeername

	def __negotiatesocks4(self,destaddr,destport):
		"""__negotiatesocks4(self,destaddr,destport)
		Negotiates a connection through a SOCKS4 server.
		"""
		# Check if the destination address provided is an IP address
		rmtrslv = False
		try:
			ipaddr = socket.inet_aton(destaddr)
		except socket.error:
			# It's a DNS name. Check where it should be resolved.
			if self.__proxy[3]==True:
				ipaddr = "\x00\x00\x00\x01"
				rmtrslv = True
			else:
				ipaddr = socket.inet_aton(socket.gethostbyname(destaddr))
		# Construct the request packet
		req = "\x04\x01" + struct.pack(">H",destport) + ipaddr
		# The username parameter is considered userid for SOCKS4
		if self.__proxy[4] != None:
			req = req + self.__proxy[4]
		req = req + "\x00"
		# DNS name if remote resolving is required
		# NOTE: This is actually an extension to the SOCKS4 protocol
		# called SOCKS4A and may not be supported in all cases.
		if rmtrslv==True:
			req = req + destaddr + "\x00"
		self.sendall(req)
		# Get the response from the server
		resp = self.__recvall(8)
		if resp[0] != "\x00":
			# Bad data
			self.close()
			raise GeneralProxyError((1,_generalerrors[1]))
		if resp[1] != "\x5A":
			# Server returned an error
			self.close()
			if ord(resp[1]) in (91,92,93):
				self.close()
				raise Socks4Error((ord(resp[1]),_socks4errors[ord(resp[1])-90]))
			else:
				raise Socks4Error((94,_socks4errors[4]))
		# Get the bound address/port
		self.__proxysockname = (socket.inet_ntoa(resp[4:]),struct.unpack(">H",resp[2:4])[0])
		if rmtrslv != None:
			self.__proxypeername = (socket.inet_ntoa(ipaddr),destport)
		else:
			self.__proxypeername = (destaddr,destport)

	def __negotiatehttp(self,destaddr,destport):
		"""__negotiatehttp(self,destaddr,destport)
		Negotiates a connection through an HTTP server.
		"""
		# If we need to resolve locally, we do this now
		if self.__proxy[3] == False:
			addr = socket.gethostbyname(destaddr)
		else:
			addr = destaddr
		self.sendall("CONNECT " + addr + ":" + str(destport) + " HTTP/1.1\r\n" + "Host: " + destaddr + "\r\n\r\n")
		# We read the response until we get the string "\r\n\r\n"
		resp = self.recv(1)
		while resp.find("\r\n\r\n")==-1:
			resp = resp + self.recv(1)
		# We just need the first line to check if the connection
		# was successful
		statusline = resp.splitlines()[0].split(" ",2)
		if statusline[0] not in ("HTTP/1.0","HTTP/1.1"):
			self.close()
			raise GeneralProxyError((1,_generalerrors[1]))
		try:
			statuscode = int(statusline[1])
		except ValueError:
			self.close()
			raise GeneralProxyError((1,_generalerrors[1]))
		if statuscode != 200:
			self.close()
			raise HTTPError((statuscode,statusline[2]))
		self.__proxysockname = ("0.0.0.0",0)
		self.__proxypeername = (addr,destport)

	def connect(self,destpair):
		"""connect(self,despair)
		Connects to the specified destination through a proxy.
		destpar - A tuple of the IP/DNS address and the port number.
		(identical to socket's connect).
		To select the proxy server use setproxy().
		"""
		# Do a minimal input check first
		if (type(destpair) in (list,tuple)==False) or (len(destpair)<2) or (type(destpair[0])!=str) or (type(destpair[1])!=int):
			raise GeneralProxyError((5,_generalerrors[5]))
		if self.__proxy[0] == PROXY_TYPE_SOCKS5:
			if self.__proxy[2] != None:
				portnum = self.__proxy[2]
			else:
				portnum = 1080
			_orgsocket.connect(self,(self.__proxy[1],portnum))
			self.__negotiatesocks5(destpair[0],destpair[1])
		elif self.__proxy[0] == PROXY_TYPE_SOCKS4:
			if self.__proxy[2] != None:
				portnum = self.__proxy[2]
			else:
				portnum = 1080
			_orgsocket.connect(self,(self.__proxy[1],portnum))
			self.__negotiatesocks4(destpair[0],destpair[1])
		elif self.__proxy[0] == PROXY_TYPE_HTTP:
			if self.__proxy[2] != None:
				portnum = self.__proxy[2]
			else:
				portnum = 8080
			_orgsocket.connect(self,(self.__proxy[1],portnum))
			self.__negotiatehttp(destpair[0],destpair[1])
		elif self.__proxy[0] == None:
			_orgsocket.connect(self,(destpair[0],destpair[1]))
		else:
			raise GeneralProxyError((4,_generalerrors[4]))