mirror of
https://gitlab.isc.org/isc-projects/bind9
synced 2025-10-19 14:27:15 +00:00
c9cb8ae9eb
This patch is strictly the result of: $ black $(git ls-files '*.py') There have been no manual changes.
272 lines
7.9 KiB
Python
272 lines
7.9 KiB
Python
# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
|
|
#
|
|
# SPDX-License-Identifier: MPL-2.0
|
|
#
|
|
# This Source Code Form is subject to the terms of the Mozilla Public
|
|
# License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
# file, you can obtain one at https://mozilla.org/MPL/2.0/.
|
|
#
|
|
# See the COPYRIGHT file distributed with this work for additional
|
|
# information regarding copyright ownership.
|
|
|
|
from __future__ import print_function
|
|
import os
|
|
import sys
|
|
import signal
|
|
import socket
|
|
import select
|
|
import struct
|
|
from datetime import datetime, timedelta
|
|
import time
|
|
import functools
|
|
|
|
import dns, dns.message, dns.query, dns.flags
|
|
from dns.rdatatype import *
|
|
from dns.rdataclass import *
|
|
from dns.rcode import *
|
|
from dns.name import *
|
|
|
|
# Log query to file
|
|
def logquery(type, qname):
|
|
with open("qlog", "a") as f:
|
|
f.write("%s %s\n", type, qname)
|
|
|
|
|
|
# Create a UDP listener
|
|
def udp_listen(ip, port, is_ipv6=False):
|
|
try:
|
|
udp = socket.socket(
|
|
socket.AF_INET6 if is_ipv6 else socket.AF_INET, socket.SOCK_DGRAM
|
|
)
|
|
try:
|
|
udp.bind((ip, port))
|
|
except:
|
|
udp.close()
|
|
udp = None
|
|
except:
|
|
udp = None
|
|
|
|
if udp is None and not is_ipv6:
|
|
raise socket.error("Can not create an IPv4 UDP listener")
|
|
|
|
return udp
|
|
|
|
|
|
# Create a TCP listener
|
|
def tcp_listen(ip, port, is_ipv6=False):
|
|
try:
|
|
tcp = socket.socket(
|
|
socket.AF_INET6 if is_ipv6 else socket.AF_INET, socket.SOCK_STREAM
|
|
)
|
|
try:
|
|
tcp.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
|
|
tcp.bind((ip, port))
|
|
tcp.listen(100)
|
|
except:
|
|
tcp.close()
|
|
tcp = None
|
|
except:
|
|
tcp = None
|
|
|
|
if tcp is None and not is_ipv6:
|
|
raise socket.error("Can not create an IPv4 TCP listener")
|
|
|
|
return tcp
|
|
|
|
|
|
############################################################################
|
|
# Control channel - send "1" or "0" to enable or disable the "silent" mode.
|
|
############################################################################
|
|
silent = False
|
|
|
|
|
|
def ctrl_channel(msg):
|
|
global silent
|
|
|
|
msg = msg.splitlines().pop(0)
|
|
print("Received control message: %s" % msg)
|
|
|
|
if len(msg) != 1:
|
|
return
|
|
|
|
if silent:
|
|
if msg == b"0":
|
|
silent = False
|
|
print("Silent mode was disabled")
|
|
else:
|
|
if msg == b"1":
|
|
silent = True
|
|
print("Silent mode was enabled")
|
|
|
|
|
|
############################################################################
|
|
# Respond to a DNS query.
|
|
############################################################################
|
|
def create_response(msg):
|
|
m = dns.message.from_wire(msg)
|
|
qname = m.question[0].name.to_text()
|
|
rrtype = m.question[0].rdtype
|
|
typename = dns.rdatatype.to_text(rrtype)
|
|
|
|
with open("query.log", "a") as f:
|
|
f.write("%s %s\n" % (typename, qname))
|
|
print("%s %s" % (typename, qname), end=" ")
|
|
|
|
r = dns.message.make_response(m)
|
|
r.set_rcode(NOERROR)
|
|
if rrtype == A:
|
|
tld = qname.split(".")[-2] + "."
|
|
ns = "local." + tld
|
|
r.answer.append(dns.rrset.from_text(qname, 300, IN, A, "10.53.0.11"))
|
|
r.answer.append(dns.rrset.from_text(tld, 300, IN, NS, "local." + tld))
|
|
r.additional.append(dns.rrset.from_text(ns, 300, IN, A, "10.53.0.11"))
|
|
elif rrtype == NS:
|
|
r.answer.append(dns.rrset.from_text(qname, 300, IN, NS, "."))
|
|
elif rrtype == SOA:
|
|
r.answer.append(dns.rrset.from_text(qname, 300, IN, SOA, ". . 0 0 0 0 0"))
|
|
else:
|
|
r.authority.append(dns.rrset.from_text(qname, 300, IN, SOA, ". . 0 0 0 0 0"))
|
|
r.flags |= dns.flags.AA
|
|
return r
|
|
|
|
|
|
def sigterm(signum, frame):
|
|
print("Shutting down now...")
|
|
os.remove("ans.pid")
|
|
running = False
|
|
sys.exit(0)
|
|
|
|
|
|
############################################################################
|
|
# Main
|
|
#
|
|
# Set up responder and control channel, open the pid file, and start
|
|
# the main loop, listening for queries on the query channel or commands
|
|
# on the control channel and acting on them.
|
|
############################################################################
|
|
ip4 = "10.53.0.11"
|
|
ip6 = "fd92:7065:b8e:ffff::11"
|
|
|
|
try:
|
|
port = int(os.environ["PORT"])
|
|
except:
|
|
port = 5300
|
|
|
|
try:
|
|
ctrlport = int(os.environ["EXTRAPORT1"])
|
|
except:
|
|
ctrlport = 5300
|
|
|
|
ctrl4_tcp = tcp_listen(ip4, ctrlport)
|
|
query4_udp = udp_listen(ip4, port)
|
|
query6_udp = udp_listen(ip6, port, is_ipv6=True)
|
|
query4_tcp = tcp_listen(ip4, port)
|
|
query6_tcp = tcp_listen(ip6, port, is_ipv6=True)
|
|
|
|
havev6 = query6_udp is not None and query6_tcp is not None
|
|
|
|
signal.signal(signal.SIGTERM, sigterm)
|
|
|
|
f = open("ans.pid", "w")
|
|
pid = os.getpid()
|
|
print(pid, file=f)
|
|
f.close()
|
|
|
|
running = True
|
|
|
|
print("Listening on %s port %d" % (ip4, ctrlport))
|
|
print("Listening on %s port %d" % (ip4, port))
|
|
if havev6:
|
|
print("Listening on %s port %d" % (ip6, port))
|
|
|
|
print("Ctrl-c to quit")
|
|
|
|
if havev6:
|
|
input = [ctrl4_tcp, query4_udp, query6_udp, query4_tcp, query6_tcp]
|
|
else:
|
|
input = [ctrl4_tcp, query4_udp, query4_tcp]
|
|
|
|
hung_conns = []
|
|
|
|
while running:
|
|
try:
|
|
inputready, outputready, exceptready = select.select(input, [], [])
|
|
except select.error as e:
|
|
break
|
|
except socket.error as e:
|
|
break
|
|
except KeyboardInterrupt:
|
|
break
|
|
|
|
for s in inputready:
|
|
if s == ctrl4_tcp:
|
|
print("Control channel connected")
|
|
conn = None
|
|
try:
|
|
# Handle control channel input
|
|
conn, addr = s.accept()
|
|
msg = conn.recv(1)
|
|
if msg:
|
|
ctrl_channel(msg)
|
|
conn.close()
|
|
except s.timeout:
|
|
pass
|
|
if conn:
|
|
conn.close()
|
|
elif s == query4_tcp or s == query6_tcp:
|
|
print(
|
|
"TCP query received on %s" % (ip4 if s == query4_tcp else ip6), end=" "
|
|
)
|
|
conn = None
|
|
try:
|
|
# Handle incoming queries
|
|
conn, addr = s.accept()
|
|
if not silent:
|
|
# get TCP message length
|
|
msg = conn.recv(2)
|
|
if len(msg) != 2:
|
|
print("NO RESPONSE (can not read the message length)")
|
|
conn.close()
|
|
continue
|
|
length = struct.unpack(">H", msg[:2])[0]
|
|
msg = conn.recv(length)
|
|
if len(msg) != length:
|
|
print("NO RESPONSE (can not read the message)")
|
|
conn.close()
|
|
continue
|
|
rsp = create_response(msg)
|
|
if rsp:
|
|
print(dns.rcode.to_text(rsp.rcode()))
|
|
wire = rsp.to_wire()
|
|
conn.send(struct.pack(">H", len(wire)))
|
|
conn.send(wire)
|
|
else:
|
|
print("NO RESPONSE (can not create a response)")
|
|
else:
|
|
# Do not respond and hang the connection.
|
|
print("NO RESPONSE (silent mode)")
|
|
hung_conns.append(conn)
|
|
continue
|
|
except socket.error as e:
|
|
print("NO RESPONSE (error: %s)" % str(e))
|
|
if conn:
|
|
conn.close()
|
|
elif s == query4_udp or s == query6_udp:
|
|
print(
|
|
"UDP query received on %s" % (ip4 if s == query4_udp else ip6), end=" "
|
|
)
|
|
# Handle incoming queries
|
|
msg = s.recvfrom(65535)
|
|
if not silent:
|
|
rsp = create_response(msg[0])
|
|
if rsp:
|
|
print(dns.rcode.to_text(rsp.rcode()))
|
|
s.sendto(rsp.to_wire(), msg[1])
|
|
else:
|
|
print("NO RESPONSE (can not create a response)")
|
|
else:
|
|
# Do not respond.
|
|
print("NO RESPONSE (silent mode)")
|
|
if not running:
|
|
break
|