proxy.py/proxy/plugin/cloudflare_dns.py

94 lines
2.9 KiB
Python

# -*- coding: utf-8 -*-
"""
proxy.py
~~~~~~~~
⚡⚡⚡ Fast, Lightweight, Pluggable, TLS interception capable proxy server focused on
Network monitoring, controls & Application development, testing, debugging.
:copyright: (c) 2013-present by Abhinav Singh and contributors.
:license: BSD, see LICENSE for more details.
.. spelling::
Cloudflare
cloudflare
dns
"""
import logging
try:
import httpx
except ImportError: # pragma: no cover
pass
from typing import Optional, Tuple
from ..common.flag import flags
from ..http.proxy import HttpProxyBasePlugin
logger = logging.getLogger(__name__)
flags.add_argument(
'--cloudflare-dns-mode',
type=str,
default='security',
help='Default: security. Either "security" (for malware protection) ' +
'or "family" (for malware and adult content protection)',
)
class CloudflareDnsResolverPlugin(HttpProxyBasePlugin):
"""This plugin uses Cloudflare DNS resolver to provide protection
against malware and adult content. Implementation uses :term:`DoH`
specification.
See https://developers.cloudflare.com/1.1.1.1/1.1.1.1-for-families
See https://developers.cloudflare.com/1.1.1.1/encrypted-dns/dns-over-https/make-api-requests/dns-json
.. note::
For this plugin to work, make sure to bypass proxy for 1.1.1.1
.. note::
This plugin requires additional dependency because :term:`DoH`
mandates a HTTP2 complaint client. Install `httpx` dependency
as::
pip install "httpx[http2]"
"""
def resolve_dns(self, host: str, port: int) -> Tuple[Optional[str], Optional[Tuple[str, int]]]:
try:
context = httpx.create_ssl_context(http2=True)
# TODO: Support resolution via Authority (SOA) to add support for
# AAAA (IPv6) query
r = httpx.get(
'https://{0}.cloudflare-dns.com/dns-query?name={1}&type=A'.format(
self.flags.cloudflare_dns_mode, host,
),
headers={'accept': 'application/dns-json'},
verify=context,
timeout=httpx.Timeout(timeout=5.0),
proxies={
'all://': None,
},
)
if r.status_code != 200:
return None, None
response = r.json()
answers = response.get('Answer', [])
if len(answers) == 0:
return None, None
# TODO: Utilize TTL to cache response locally
# instead of making a DNS query repeatedly for the same host.
return answers[0]['data'], None
except Exception as e:
logger.info(
'Unable to resolve DNS-over-HTTPS for host {0} : {1}'.format(
host, str(e),
),
)
return None, None