Files
Iliyan Angelov c67067a2a4 Mail
2025-09-14 23:24:25 +03:00

439 lines
16 KiB
Python

import sys
import dns._features
# pylint: disable=W0612,W0613,C0301
if sys.platform == "win32":
import ctypes
import ctypes.wintypes as wintypes
import winreg # pylint: disable=import-error
from enum import IntEnum
import dns.name
# Keep pylint quiet on non-windows.
try:
_ = WindowsError # pylint: disable=used-before-assignment
except NameError:
WindowsError = Exception
class ConfigMethod(IntEnum):
Registry = 1
WMI = 2
Win32 = 3
class DnsInfo:
def __init__(self):
self.domain = None
self.nameservers = []
self.search = []
_config_method = ConfigMethod.Registry
if dns._features.have("wmi"):
import threading
import pythoncom # pylint: disable=import-error
import wmi # pylint: disable=import-error
# Prefer WMI by default if wmi is installed.
_config_method = ConfigMethod.WMI
class _WMIGetter(threading.Thread):
# pylint: disable=possibly-used-before-assignment
def __init__(self):
super().__init__()
self.info = DnsInfo()
def run(self):
pythoncom.CoInitialize()
try:
system = wmi.WMI()
for interface in system.Win32_NetworkAdapterConfiguration():
if interface.IPEnabled and interface.DNSServerSearchOrder:
self.info.nameservers = list(interface.DNSServerSearchOrder)
if interface.DNSDomain:
self.info.domain = _config_domain(interface.DNSDomain)
if interface.DNSDomainSuffixSearchOrder:
self.info.search = [
_config_domain(x)
for x in interface.DNSDomainSuffixSearchOrder
]
break
finally:
pythoncom.CoUninitialize()
def get(self):
# We always run in a separate thread to avoid any issues with
# the COM threading model.
self.start()
self.join()
return self.info
else:
class _WMIGetter: # type: ignore
pass
def _config_domain(domain):
# Sometimes DHCP servers add a '.' prefix to the default domain, and
# Windows just stores such values in the registry (see #687).
# Check for this and fix it.
if domain.startswith("."):
domain = domain[1:]
return dns.name.from_text(domain)
class _RegistryGetter:
def __init__(self):
self.info = DnsInfo()
def _split(self, text):
# The windows registry has used both " " and "," as a delimiter, and while
# it is currently using "," in Windows 10 and later, updates can seemingly
# leave a space in too, e.g. "a, b". So we just convert all commas to
# spaces, and use split() in its default configuration, which splits on
# all whitespace and ignores empty strings.
return text.replace(",", " ").split()
def _config_nameservers(self, nameservers):
for ns in self._split(nameservers):
if ns not in self.info.nameservers:
self.info.nameservers.append(ns)
def _config_search(self, search):
for s in self._split(search):
s = _config_domain(s)
if s not in self.info.search:
self.info.search.append(s)
def _config_fromkey(self, key, always_try_domain):
try:
servers, _ = winreg.QueryValueEx(key, "NameServer")
except WindowsError:
servers = None
if servers:
self._config_nameservers(servers)
if servers or always_try_domain:
try:
dom, _ = winreg.QueryValueEx(key, "Domain")
if dom:
self.info.domain = _config_domain(dom)
except WindowsError:
pass
else:
try:
servers, _ = winreg.QueryValueEx(key, "DhcpNameServer")
except WindowsError:
servers = None
if servers:
self._config_nameservers(servers)
try:
dom, _ = winreg.QueryValueEx(key, "DhcpDomain")
if dom:
self.info.domain = _config_domain(dom)
except WindowsError:
pass
try:
search, _ = winreg.QueryValueEx(key, "SearchList")
except WindowsError:
search = None
if search is None:
try:
search, _ = winreg.QueryValueEx(key, "DhcpSearchList")
except WindowsError:
search = None
if search:
self._config_search(search)
def _is_nic_enabled(self, lm, guid):
# Look in the Windows Registry to determine whether the network
# interface corresponding to the given guid is enabled.
#
# (Code contributed by Paul Marks, thanks!)
#
try:
# This hard-coded location seems to be consistent, at least
# from Windows 2000 through Vista.
connection_key = winreg.OpenKey(
lm,
r"SYSTEM\CurrentControlSet\Control\Network"
r"\{4D36E972-E325-11CE-BFC1-08002BE10318}"
rf"\{guid}\Connection",
)
try:
# The PnpInstanceID points to a key inside Enum
(pnp_id, ttype) = winreg.QueryValueEx(
connection_key, "PnpInstanceID"
)
if ttype != winreg.REG_SZ:
raise ValueError # pragma: no cover
device_key = winreg.OpenKey(
lm, rf"SYSTEM\CurrentControlSet\Enum\{pnp_id}"
)
try:
# Get ConfigFlags for this device
(flags, ttype) = winreg.QueryValueEx(device_key, "ConfigFlags")
if ttype != winreg.REG_DWORD:
raise ValueError # pragma: no cover
# Based on experimentation, bit 0x1 indicates that the
# device is disabled.
#
# XXXRTH I suspect we really want to & with 0x03 so
# that CONFIGFLAGS_REMOVED devices are also ignored,
# but we're shifting to WMI as ConfigFlags is not
# supposed to be used.
return not flags & 0x1
finally:
device_key.Close()
finally:
connection_key.Close()
except Exception: # pragma: no cover
return False
def get(self):
"""Extract resolver configuration from the Windows registry."""
lm = winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE)
try:
tcp_params = winreg.OpenKey(
lm, r"SYSTEM\CurrentControlSet\Services\Tcpip\Parameters"
)
try:
self._config_fromkey(tcp_params, True)
finally:
tcp_params.Close()
interfaces = winreg.OpenKey(
lm,
r"SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces",
)
try:
i = 0
while True:
try:
guid = winreg.EnumKey(interfaces, i)
i += 1
key = winreg.OpenKey(interfaces, guid)
try:
if not self._is_nic_enabled(lm, guid):
continue
self._config_fromkey(key, False)
finally:
key.Close()
except OSError:
break
finally:
interfaces.Close()
finally:
lm.Close()
return self.info
class _Win32Getter(_RegistryGetter):
def get(self):
"""Get the attributes using the Windows API."""
# Load the IP Helper library
# # https://learn.microsoft.com/en-us/windows/win32/api/iphlpapi/nf-iphlpapi-getadaptersaddresses
IPHLPAPI = ctypes.WinDLL("Iphlpapi.dll")
# Constants
AF_UNSPEC = 0
ERROR_SUCCESS = 0
GAA_FLAG_INCLUDE_PREFIX = 0x00000010
AF_INET = 2
AF_INET6 = 23
IF_TYPE_SOFTWARE_LOOPBACK = 24
# Define necessary structures
class SOCKADDRV4(ctypes.Structure):
_fields_ = [
("sa_family", wintypes.USHORT),
("sa_data", ctypes.c_ubyte * 14),
]
class SOCKADDRV6(ctypes.Structure):
_fields_ = [
("sa_family", wintypes.USHORT),
("sa_data", ctypes.c_ubyte * 26),
]
class SOCKET_ADDRESS(ctypes.Structure):
_fields_ = [
("lpSockaddr", ctypes.POINTER(SOCKADDRV4)),
("iSockaddrLength", wintypes.INT),
]
class IP_ADAPTER_DNS_SERVER_ADDRESS(ctypes.Structure):
pass # Forward declaration
IP_ADAPTER_DNS_SERVER_ADDRESS._fields_ = [
("Length", wintypes.ULONG),
("Reserved", wintypes.DWORD),
("Next", ctypes.POINTER(IP_ADAPTER_DNS_SERVER_ADDRESS)),
("Address", SOCKET_ADDRESS),
]
class IF_LUID(ctypes.Structure):
_fields_ = [("Value", ctypes.c_ulonglong)]
class NET_IF_NETWORK_GUID(ctypes.Structure):
_fields_ = [("Value", ctypes.c_ubyte * 16)]
class IP_ADAPTER_PREFIX_XP(ctypes.Structure):
pass # Left undefined here for simplicity
class IP_ADAPTER_GATEWAY_ADDRESS_LH(ctypes.Structure):
pass # Left undefined here for simplicity
class IP_ADAPTER_DNS_SUFFIX(ctypes.Structure):
_fields_ = [
("String", ctypes.c_wchar * 256),
("Next", ctypes.POINTER(ctypes.c_void_p)),
]
class IP_ADAPTER_UNICAST_ADDRESS_LH(ctypes.Structure):
pass # Left undefined here for simplicity
class IP_ADAPTER_MULTICAST_ADDRESS_XP(ctypes.Structure):
pass # Left undefined here for simplicity
class IP_ADAPTER_ANYCAST_ADDRESS_XP(ctypes.Structure):
pass # Left undefined here for simplicity
class IP_ADAPTER_DNS_SERVER_ADDRESS_XP(ctypes.Structure):
pass # Left undefined here for simplicity
class IP_ADAPTER_ADDRESSES(ctypes.Structure):
pass # Forward declaration
IP_ADAPTER_ADDRESSES._fields_ = [
("Length", wintypes.ULONG),
("IfIndex", wintypes.DWORD),
("Next", ctypes.POINTER(IP_ADAPTER_ADDRESSES)),
("AdapterName", ctypes.c_char_p),
("FirstUnicastAddress", ctypes.POINTER(SOCKET_ADDRESS)),
("FirstAnycastAddress", ctypes.POINTER(SOCKET_ADDRESS)),
("FirstMulticastAddress", ctypes.POINTER(SOCKET_ADDRESS)),
(
"FirstDnsServerAddress",
ctypes.POINTER(IP_ADAPTER_DNS_SERVER_ADDRESS),
),
("DnsSuffix", wintypes.LPWSTR),
("Description", wintypes.LPWSTR),
("FriendlyName", wintypes.LPWSTR),
("PhysicalAddress", ctypes.c_ubyte * 8),
("PhysicalAddressLength", wintypes.ULONG),
("Flags", wintypes.ULONG),
("Mtu", wintypes.ULONG),
("IfType", wintypes.ULONG),
("OperStatus", ctypes.c_uint),
# Remaining fields removed for brevity
]
def format_ipv4(sockaddr_in):
return ".".join(map(str, sockaddr_in.sa_data[2:6]))
def format_ipv6(sockaddr_in6):
# The sa_data is:
#
# USHORT sin6_port;
# ULONG sin6_flowinfo;
# IN6_ADDR sin6_addr;
# ULONG sin6_scope_id;
#
# which is 2 + 4 + 16 + 4 = 26 bytes, and we need the plus 6 below
# to be in the sin6_addr range.
parts = [
sockaddr_in6.sa_data[i + 6] << 8 | sockaddr_in6.sa_data[i + 6 + 1]
for i in range(0, 16, 2)
]
return ":".join(f"{part:04x}" for part in parts)
buffer_size = ctypes.c_ulong(15000)
while True:
buffer = ctypes.create_string_buffer(buffer_size.value)
ret_val = IPHLPAPI.GetAdaptersAddresses(
AF_UNSPEC,
GAA_FLAG_INCLUDE_PREFIX,
None,
buffer,
ctypes.byref(buffer_size),
)
if ret_val == ERROR_SUCCESS:
break
elif ret_val != 0x6F: # ERROR_BUFFER_OVERFLOW
print(f"Error retrieving adapter information: {ret_val}")
return
adapter_addresses = ctypes.cast(
buffer, ctypes.POINTER(IP_ADAPTER_ADDRESSES)
)
current_adapter = adapter_addresses
while current_adapter:
# Skip non-operational adapters.
oper_status = current_adapter.contents.OperStatus
if oper_status != 1:
current_adapter = current_adapter.contents.Next
continue
# Exclude loopback adapters.
if current_adapter.contents.IfType == IF_TYPE_SOFTWARE_LOOPBACK:
current_adapter = current_adapter.contents.Next
continue
# Get the domain from the DnsSuffix attribute.
dns_suffix = current_adapter.contents.DnsSuffix
if dns_suffix:
self.info.domain = dns.name.from_text(dns_suffix)
current_dns_server = current_adapter.contents.FirstDnsServerAddress
while current_dns_server:
sockaddr = current_dns_server.contents.Address.lpSockaddr
sockaddr_family = sockaddr.contents.sa_family
ip = None
if sockaddr_family == AF_INET: # IPv4
ip = format_ipv4(sockaddr.contents)
elif sockaddr_family == AF_INET6: # IPv6
sockaddr = ctypes.cast(sockaddr, ctypes.POINTER(SOCKADDRV6))
ip = format_ipv6(sockaddr.contents)
if ip:
if ip not in self.info.nameservers:
self.info.nameservers.append(ip)
current_dns_server = current_dns_server.contents.Next
current_adapter = current_adapter.contents.Next
# Use the registry getter to get the search info, since it is set at the system level.
registry_getter = _RegistryGetter()
info = registry_getter.get()
self.info.search = info.search
return self.info
def set_config_method(method: ConfigMethod) -> None:
global _config_method
_config_method = method
def get_dns_info() -> DnsInfo:
"""Extract resolver configuration."""
if _config_method == ConfigMethod.Win32:
getter = _Win32Getter()
elif _config_method == ConfigMethod.WMI:
getter = _WMIGetter()
else:
getter = _RegistryGetter()
return getter.get()