python source code of network

import socket
import struct
import ctypes
import binascii
from contextlib import closing

from .platform import WINDOWS
from .string import safeencode, safeunicode
from .convert import hex2dec, dec2hex


# https://github.com/hickeroar/win_inet_pton/blob/master/win_inet_pton.py
if WINDOWS:
    class _sockaddr(ctypes.Structure):
        _fields_ = [("sa_family", ctypes.c_short),
                    ("__pad1", ctypes.c_ushort),
                    ("ipv4_addr", ctypes.c_byte * 4),
                    ("ipv6_addr", ctypes.c_byte * 16),
                    ("__pad2", ctypes.c_ulong)]


    WSAStringToAddressA = ctypes.windll.ws2_32.WSAStringToAddressA
    WSAAddressToStringA = ctypes.windll.ws2_32.WSAAddressToStringA


    def _win_inet_pton(address_family, ip_str):
        ip_str = safeencode(ip_str)
        addr = _sockaddr()
        addr.sa_family = address_family
        addr_size = ctypes.c_int(ctypes.sizeof(addr))

        if WSAStringToAddressA(
                ip_str,
                address_family,
                None,
                ctypes.byref(addr),
                ctypes.byref(addr_size)
        ) != 0:
            raise socket.error(ctypes.FormatError())

        if address_family == socket.AF_INET:
            return ctypes.string_at(addr.ipv4_addr, 4)
        if address_family == socket.AF_INET6:
            return ctypes.string_at(addr.ipv6_addr, 16)

        raise socket.error('unknown address family')


    def _win_inet_ntop(address_family, packed_ip):
        addr = _sockaddr()
        addr.sa_family = address_family
        addr_size = ctypes.c_int(ctypes.sizeof(addr))
        ip_string = ctypes.create_string_buffer(128)
        ip_string_size = ctypes.c_int(ctypes.sizeof(ip_string))

        if address_family == socket.AF_INET:
            if len(packed_ip) != ctypes.sizeof(addr.ipv4_addr):
                raise socket.error('packed IP wrong length for inet_ntoa')
            ctypes.memmove(addr.ipv4_addr, packed_ip, 4)
        elif address_family == socket.AF_INET6:
            if len(packed_ip) != ctypes.sizeof(addr.ipv6_addr):
                raise socket.error('packed IP wrong length for inet_ntoa')
            ctypes.memmove(addr.ipv6_addr, packed_ip, 16)
        else:
            raise socket.error('unknown address family')

        if WSAAddressToStringA(
                ctypes.byref(addr),
                addr_size,
                None,
                ip_string,
                ctypes.byref(ip_string_size)
        ) != 0:
            raise socket.error(ctypes.FormatError())

        return ip_string[:ip_string_size.value - 1]


    socket.inet_pton = _win_inet_pton
    socket.inet_ntop = _win_inet_ntop


# https://github.com/kennethreitz/requests/blob/master/requests/utils.py
def dotted_netmask(mask):
    """
    Converts mask from /xx format to xxx.xxx.xxx.xxx
    Example: if mask is 24 function returns 255.255.255.0
    """
    mask = int(mask)
    bits = 0xffffffff ^ (1 << 32 - mask) - 1
    return socket.inet_ntoa(struct.pack('>I', bits))


# http://en.wikipedia.org/wiki/Private_network
private_ipv4s = [
    ('10.0.0.0', 8),  # 10.0.0.0 - 10.255.255.255
    ('172.16.0.0', 12),  # 172.16.0.0 - 172.31.255.255
    ('192.168.0.0', 16),  # 192.168.0.0 - 192.168.255.255
]


# https://github.com/kennethreitz/requests/blob/master/requests/utils.py
def is_ipv4(ip):
    """
    Returns True if the IPv4 address ia valid, otherwise returns False.
    """
    try:
        socket.inet_aton(ip)
    except socket.error:
        return False
    return True


def is_ipv6(ip):
    """
    Returns True if the IPv6 address ia valid, otherwise returns False.
    """
    try:
        socket.inet_pton(socket.AF_INET6, ip)
    except socket.error:
        return False
    return True


def get_free_port():
    with closing(socket.socket(socket.AF_INET, type=socket.SOCK_STREAM)) as s:
        s.bind(('127.0.0.1', 0))
        _, port = s.getsockname()
    return port


# https://stackoverflow.com/questions/5619685/conversion-from-ip-string-to-integer-and-backward-in-python
# https://stackoverflow.com/questions/11894717/python-convert-ipv6-to-an-integer
def ip2int(ip_str):
    """
    Convert ip to integer. Support IPV4 and IPV6.
    Raise `ValueError` if convert failed.
    """
    try:
        return struct.unpack("!I", socket.inet_aton(ip_str))[0]
    except socket.error:
        pass

    try:
        return hex2dec(binascii.hexlify(socket.inet_pton(socket.AF_INET6, ip_str)))
    except socket.error:
        pass

    raise ValueError('{!r} does not appear to be an IPv4 or IPv6 address'.format(ip_str))


# https://stackoverflow.com/questions/5619685/conversion-from-ip-string-to-integer-and-backward-in-python
def int2ip(ip_int):
    """
    Convert integer to ip. Support IPV4 and IPV6.
    Raise `ValueError` if convert failed.
    """
    try:
        return socket.inet_ntoa(struct.pack("!I", ip_int))
    except (socket.error, struct.error):
        pass

    try:
        ip_str = socket.inet_ntop(socket.AF_INET6, binascii.unhexlify(dec2hex(ip_int)))
        return safeunicode(ip_str, encoding='ascii')
    except (socket.error, struct.error):
        pass

    raise ValueError('{!r} does not appear to be an IPv4 or IPv6 address'.format(ip_int))