(Non-standard) HTTP DNS resolver. I used it to hijack some Chinese apps' queries on my home gateway during 2019–2021. May not work today.

httpdns.py

#!/usr/bin/env python3
import asyncio
import logging
from typing import Tuple, List

from aiohttp import web
from aiodnsresolver import Resolver, TYPES, DnsRecordDoesNotExist
from des import DesKey

TENCENT_KEYS = {
        '146': b'K@ahDRdl',
        '338': b']YPNNMwW',
        '3092': b'LkgBm3xj',
}


async def resolve(request: web.Request) -> Tuple[str, List[str], int]:
    host = request.query.get('host') or request.query.get('dn')
    if host is None:
        raise web.HTTPBadRequest(text='missing query')
    if not '.' in host:
        logging.info('not a domain: %s', host)
        raise web.HTTPBadRequest(text='not a domain')
    try:
        ips, ttl = await resolver.query(host)
    except DnsRecordDoesNotExist:
        logging.info('NXDOMAIN: %s', host)
        raise web.HTTPNotFound(text='NXDOMAIN')
    return host, ips, ttl


async def handle_aliyun(request: web.Request) -> web.Response:
    host, ips, ttl = await resolve(request)
    return web.json_response(dict(host=host, ips=ips, ttl=ttl))


async def handle_tencent(request: web.Request) -> web.Response:
    key_id = request.query.get('id')
    ttl_enabled = request.query.get('ttl') == '1'
    if key_id is None:
        _, ips, ttl = await resolve(request)
        cipher = None
    else:
        key = TENCENT_KEYS.get(key_id)
        if key is None:
            logging.info('missing key: %s', key_id)
            raise web.HTTPNotFound(text='Missing keys')
        cipher = DesKey(key)

        host = request.query.get('host') or request.query['dn']
        host = bytes.fromhex(host)
        host = cipher.decrypt(host, padding=True).decode('utf8')
        ips, ttl = await resolver.query(host)

    if ttl_enabled:
        resp = ';'.join(f'{ip},{ttl}' for ip in ips)
    else:
        resp = ';'.join(ips)

    if cipher is not None:
        resp = cipher.encrypt(resp.encode('utf8'), padding=True).hex()
    return web.Response(text=resp)

async def handle_zhihu(request: web.Request) -> web.Response:
    host = request.query['host']
    if ',' not in host:
        host, ips, ttl = await resolve(request)
        resp = dict(host=host, ips=ips, ttl=ttl, origin_ttl=ttl)
    else:
        resp = []
        for host in host.split(','):
            ips, ttl = await resolver.query(host)
            resp.append(dict(host=host, ips=ips, ttl=ttl, origin_ttl=ttl))
    return web.json_response(dict(dns=resp))


class HostChooser:
    def __init__(self):
        self._host_handler = {}

    async def do_route(self, request: web.Request):
        handler = self._host_handler.get(request.host)
        if handler is not None:
            return await handler(request)
        logging.info('Unknown host: %s', request.host)
        raise web.HTTPNotFound()

    def add(self, host: str, handler):
        self._host_handler[host] = handler


class DNSResolver:
    _resolve = None
    _loop = None

    async def query(self, host: str) -> Tuple[List[str], int]:
        if self._resolve is None:
            self._resolve, _ = Resolver()
        if self._loop is None:
            self._loop = asyncio.get_event_loop()
        ips = await self._resolve(host, TYPES.A)
        ttl = int(max(0, min(ip.expires_at for ip in ips) - self._loop.time()))
        ips = [str(ip) for ip in ips]
        return ips, ttl


app = web.Application()
resolver = DNSResolver()
hosts = HostChooser()
app.add_routes([web.get('/{path:.*}', hosts.do_route)])

hosts.add('203.107.1.33', handle_aliyun)
hosts.add('203.107.1.34', handle_aliyun)
hosts.add('203.107.1.65', handle_aliyun)
hosts.add('203.107.1.66', handle_aliyun)
hosts.add('119.29.29.29', handle_tencent)
hosts.add('118.89.204.198', handle_zhihu)


if __name__ == '__main__':
    logging.basicConfig(level=logging.INFO)
    logging.getLogger('aiodnsresolver').setLevel(logging.WARN)
    web.run_app(app, host='127.0.0.80', port=8011)

requirements.txt

aiodnsresolver==0.0.151
aiohttp==3.7.3
async-timeout==3.0.1
attrs==20.3.0
chardet==3.0.4
des==1.0.5
idna==2.10
multidict==5.0.2
typing-extensions==3.7.4.3
yarl==1.6.3