# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.

"""
Windows implementation of local network interface enumeration.
"""

from socket import socket, AF_INET6, SOCK_STREAM
from ctypes import (
WinDLL, byref, create_string_buffer, c_int, c_void_p,
POINTER, Structure, cast, string_at)

WS2_32 = WinDLL('ws2_32')

SOCKET = c_int
DWORD = c_int
LPVOID = c_void_p
LPSOCKADDR = c_void_p
LPWSAPROTOCOL_INFO = c_void_p
LPTSTR = c_void_p
LPDWORD = c_void_p
LPWSAOVERLAPPED = c_void_p
LPWSAOVERLAPPED_COMPLETION_ROUTINE = c_void_p

# http://msdn.microsoft.com/en-us/library/ms741621(v=VS.85).aspx
# int WSAIoctl(
# __in SOCKET s,
# __in DWORD dwIoControlCode,
# __in LPVOID lpvInBuffer,
# __in DWORD cbInBuffer,
# __out LPVOID lpvOutBuffer,
# __in DWORD cbOutBuffer,
# __out LPDWORD lpcbBytesReturned,
# __in LPWSAOVERLAPPED lpOverlapped,
# __in LPWSAOVERLAPPED_COMPLETION_ROUTINE lpCompletionRoutine
# );
WSAIoctl = WS2_32.WSAIoctl
WSAIoctl.argtypes = [
SOCKET, DWORD, LPVOID, DWORD, LPVOID, DWORD, LPDWORD,
LPWSAOVERLAPPED, LPWSAOVERLAPPED_COMPLETION_ROUTINE]
WSAIoctl.restype = c_int

# http://msdn.microsoft.com/en-us/library/ms741516(VS.85).aspx
# INT WSAAPI WSAAddressToString(
# __in LPSOCKADDR lpsaAddress,
# __in DWORD dwAddressLength,
# __in_opt LPWSAPROTOCOL_INFO lpProtocolInfo,
# __inout LPTSTR lpszAddressString,
# __inout LPDWORD lpdwAddressStringLength
# );
WSAAddressToString = WS2_32.WSAAddressToStringA
WSAAddressToString.argtypes = [
LPSOCKADDR, DWORD, LPWSAPROTOCOL_INFO, LPTSTR, LPDWORD]
WSAAddressToString.restype = c_int


SIO_ADDRESS_LIST_QUERY = 0x48000016
WSAEFAULT = 10014

class SOCKET_ADDRESS(Structure):
_fields_ = [('lpSockaddr', c_void_p),
('iSockaddrLength', c_int)]



def make_SAL(ln):
class SOCKET_ADDRESS_LIST(Structure):
_fields_ = [('iAddressCount', c_int),
('Address', SOCKET_ADDRESS * ln)]
return SOCKET_ADDRESS_LIST



def win32GetLinkLocalIPv6Addresses():
"""
Return a list of strings in colon-hex format representing all the link local
IPv6 addresses available on the system, as reported by
I{WSAIoctl}/C{SIO_ADDRESS_LIST_QUERY}.
"""
s = socket(AF_INET6, SOCK_STREAM)
size = 4096
retBytes = c_int()
for i in range(2):
buf = create_string_buffer(size)
ret = WSAIoctl(
s.fileno(),
SIO_ADDRESS_LIST_QUERY, 0, 0, buf, size, byref(retBytes), 0, 0)

# WSAIoctl might fail with WSAEFAULT, which means there was not enough
# space in the buffer we gave it. There's no way to check the errno
# until Python 2.6, so we don't even try. :/ Maybe if retBytes is still
# 0 another error happened, though.
if ret and retBytes.value:
size = retBytes.value
else:
break

# If it failed, then we'll just have to give up. Still no way to see why.
if ret:
raise RuntimeError("WSAIoctl failure")

addrList = cast(buf, POINTER(make_SAL(0)))
addrCount = addrList[0].iAddressCount
addrList = cast(buf, POINTER(make_SAL(addrCount)))

addressStringBufLength = 1024
addressStringBuf = create_string_buffer(addressStringBufLength)

retList = []
for i in range(addrList[0].iAddressCount):
retBytes.value = addressStringBufLength
addr = addrList[0].Address[i]
ret = WSAAddressToString(
addr.lpSockaddr, addr.iSockaddrLength, 0, addressStringBuf,
byref(retBytes))
if ret:
raise RuntimeError("WSAAddressToString failure")
retList.append(string_at(addressStringBuf))
return [addr for addr in retList if '%' in addr]