work in progress ctypes back-port of windows socket sharing from Python 3.3 to Python 2.7; eventual use case is cross-process socket pool; maybe even fancier things as well

sockshare.py

import ctypes
import struct
import socket

WIN32 = True

if WIN32:
    def pass_sock():
        pass

    def sock2share(sock, pid):
        share = ctypes.create_string_buffer(256)
        #being cautious on size
        err = dup_sock(sock.fileno(), pid, share)
        if err:
            err = get_err()
            raise Exception("WSADuplicateSocketA error: "+str(err))
        return share

    def share2sock(share, family=None, type=None, proto=None):
        x = FROM_PROTOCOL_INFO
        sockid = wsa_sock(x, x, x, share, 0, 1)  # 1=WSA_FLAG_OVERLAPPED
        if family is None:
            family = INT.unpack_from(share, WSAPROTOCOL_INFO_FAMILY)[0]
        if type is None:
            type = INT.unpack_from(share, WSAPROTOCOL_INFO_TYPE)[0]
        if proto is None:
            proto = INT.unpack_from(share, WSAPROTOCOL_INFO_PROTO)
        #everything but this last line works...
        #how to convert windows socket id to python socket object?
        return socket.socket(family, type, proto, sockid)

    dup_sock = ctypes.windll.Ws2_32.WSADuplicateSocketA
    get_err = ctypes.windll.Ws2_32.WSAGetLastError
    wsa_sock = ctypes.windll.Ws2_32.WSASocketA

    FROM_PROTOCOL_INFO = -1  # defined in winsock2.h
    #offsets of some fields inside WSAPROTOCOL_INFO struct
    WSAPROTOCOL_INFO_FAMILY = 73
    WSAPROTOCOL_INFO_TYPE = 85
    WSAPROTOCOL_INFO_PROTO = 89

    INT = struct.Struct('>L')

    def test():
        import os

        s = socket.socket()
        s.connect(('google.com', 80))
        s2 = share2sock(sock2share(s, os.getpid()))
        return s2

else:
    #IOU unix method as well
    pass