rayyee · January 4, 2022 01:28 · Sep 26, 2021 · Aug 20, 2014 · Aug 20, 2014 · Aug 20, 2014
diff --git a/ddnsserver.py b/ddnsserver.py
@@ -1,5 +1,7 @@
 #!/usr/bin/env python
-# coding=utf-8
+"""
+LICENSE http://www.apache.org/licenses/LICENSE-2.0
+"""
 
 import argparse
 import datetime

diff --git a/ddnsserver.py b/ddnsserver.py
@@ -124,16 +124,20 @@ def send_data(self, data):
 
 def main():
     parser = argparse.ArgumentParser(description='Start a DNS implemented in Python.')
+    parser = argparse.ArgumentParser(description='Start a DNS implemented in Python. Usually DNSs use UDP on port 53.')
     parser.add_argument('--port', default=5053, type=int, help='The port to listen on.')
+    parser.add_argument('--tcp', action='store_true', help='Listen to TCP connections.')
+    parser.add_argument('--udp', action='store_true', help='Listen to UDP datagrams.')
 
     args = parser.parse_args()
+    if not (args.udp or args.tcp): parser.error("Please select at least one of --udp or --tcp.")
 
     print("Starting nameserver...")
 
-    servers = [
-        socketserver.ThreadingUDPServer(('', args.port), UDPRequestHandler),
-        socketserver.ThreadingTCPServer(('', args.port), TCPRequestHandler),
-    ]
+    servers = []
+    if args.udp: servers.append(socketserver.ThreadingUDPServer(('', args.port), UDPRequestHandler))
+    if args.tcp: servers.append(socketserver.ThreadingTCPServer(('', args.port), TCPRequestHandler))
+
     for s in servers:
         thread = threading.Thread(target=s.serve_forever)  # that thread will start one more thread for each request
         thread.daemon = True  # exit the server thread when the main thread terminates

diff --git a/ddnsserver.py b/ddnsserver.py
@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 # coding=utf-8
 
+import argparse
 import datetime
 import sys
 import time
@@ -23,7 +24,6 @@ def __getattr__(self, item):
 D = DomainName('example.com.')
 IP = '127.0.0.1'
 TTL = 60 * 5
-PORT = 5053
 
 soa_record = SOA(
     mname=D.ns1,  # primary name server
@@ -122,12 +122,17 @@ def send_data(self, data):
         return self.request[1].sendto(data, self.client_address)
 
 
-if __name__ == '__main__':
+def main():
+    parser = argparse.ArgumentParser(description='Start a DNS implemented in Python.')
+    parser.add_argument('--port', default=5053, type=int, help='The port to listen on.')
+
+    args = parser.parse_args()
+
     print("Starting nameserver...")
 
     servers = [
-        socketserver.ThreadingUDPServer(('', PORT), UDPRequestHandler),
-        socketserver.ThreadingTCPServer(('', PORT), TCPRequestHandler),
+        socketserver.ThreadingUDPServer(('', args.port), UDPRequestHandler),
+        socketserver.ThreadingTCPServer(('', args.port), TCPRequestHandler),
     ]
     for s in servers:
         thread = threading.Thread(target=s.serve_forever)  # that thread will start one more thread for each request
@@ -146,3 +151,7 @@ def send_data(self, data):
     finally:
         for s in servers:
             s.shutdown()
+
+if __name__ == '__main__':
+    main()
+
diff --git a/ddnsserver.py b/ddnsserver.py
@@ -8,7 +8,11 @@
 import traceback
 import socketserver
 import struct
-from dnslib import *
+try:
+    from dnslib import *
+except ImportError:
+    print("Missing dependency dnslib: <https://pypi.python.org/pypi/dnslib>. Please install it with `pip`.")
+    sys.exit(2)
 
 
 class DomainName(str):

diff --git a/ddnsserver.py b/ddnsserver.py
@@ -61,12 +61,12 @@ def dns_response(data):
                 for rdata in rrs:
                     rqt = rdata.__class__.__name__
                     if qt in ['*', rqt]:
-                        reply.add_answer(RR(rname=qname, rtype=QTYPE[rqt], rclass=1, ttl=TTL, rdata=rdata))
+                        reply.add_answer(RR(rname=qname, rtype=getattr(QTYPE, rqt), rclass=1, ttl=TTL, rdata=rdata))
 
         for rdata in ns_records:
-            reply.add_ns(RR(rname=D, rtype=QTYPE.NS, rclass=1, ttl=TTL, rdata=rdata))
+            reply.add_ar(RR(rname=D, rtype=QTYPE.NS, rclass=1, ttl=TTL, rdata=rdata))
 
-        reply.add_ns(RR(rname=D, rtype=QTYPE.SOA, rclass=1, ttl=TTL, rdata=soa_record))
+        reply.add_auth(RR(rname=D, rtype=QTYPE.SOA, rclass=1, ttl=TTL, rdata=soa_record))
 
     print("---- Reply:\n", reply)
 

diff --git a/ddnsserver.py b/ddnsserver.py
@@ -16,7 +16,7 @@ def __getattr__(self, item):
         return DomainName(item + '.' + self)
 
 
-D = DomainName('example.com')
+D = DomainName('example.com.')
 IP = '127.0.0.1'
 TTL = 60 * 5
 PORT = 5053

diff --git a/ddnsserver.py b/ddnsserver.py
@@ -7,6 +7,7 @@
 import threading
 import traceback
 import socketserver
+import struct
 from dnslib import *
 
 
@@ -86,7 +87,7 @@ def handle(self):
                                                self.client_address[1]))
         try:
             data = self.get_data()
-            print(len(data), data.encode('hex'))  # repr(data).replace('\\x', '')[1:-1]
+            print(len(data), data)  # repr(data).replace('\\x', '')[1:-1]
             self.send_data(dns_response(data))
         except Exception:
             traceback.print_exc(file=sys.stderr)
@@ -96,15 +97,15 @@ class TCPRequestHandler(BaseRequestHandler):
 
     def get_data(self):
         data = self.request.recv(8192).strip()
-        sz = int(data[:2].encode('hex'), 16)
+        sz = struct.unpack('>H', data[:2])[0]
         if sz < len(data) - 2:
             raise Exception("Wrong size of TCP packet")
         elif sz > len(data) - 2:
             raise Exception("Too big TCP packet")
         return data[2:]
 
     def send_data(self, data):
-        sz = hex(len(data))[2:].zfill(4).decode('hex')
+        sz = struct.pack('>H', len(data))
         return self.request.sendall(sz + data)
 
 

diff --git a/ddnsserver.py b/ddnsserver.py
@@ -6,7 +6,7 @@
 import time
 import threading
 import traceback
-import SocketServer
+import socketserver
 from dnslib import *
 
 
@@ -44,7 +44,7 @@ def __getattr__(self, item):
 def dns_response(data):
     request = DNSRecord.parse(data)
 
-    print request
+    print(request)
 
     reply = DNSRecord(DNSHeader(id=request.header.id, qr=1, aa=1, ra=1), q=request.q)
 
@@ -55,7 +55,7 @@ def dns_response(data):
 
     if qn == D or qn.endswith('.' + D):
 
-        for name, rrs in records.iteritems():
+        for name, rrs in records.items():
             if name == qn:
                 for rdata in rrs:
                     rqt = rdata.__class__.__name__
@@ -67,12 +67,12 @@ def dns_response(data):
 
         reply.add_ns(RR(rname=D, rtype=QTYPE.SOA, rclass=1, ttl=TTL, rdata=soa_record))
 
-    print "---- Reply:\n", reply
+    print("---- Reply:\n", reply)
 
     return reply.pack()
 
 
-class BaseRequestHandler(SocketServer.BaseRequestHandler):
+class BaseRequestHandler(socketserver.BaseRequestHandler):
 
     def get_data(self):
         raise NotImplementedError
@@ -82,11 +82,11 @@ def send_data(self, data):
 
     def handle(self):
         now = datetime.datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')
-        print "\n\n%s request %s (%s %s):" % (self.__class__.__name__[:3], now, self.client_address[0],
-                                               self.client_address[1])
+        print("\n\n%s request %s (%s %s):" % (self.__class__.__name__[:3], now, self.client_address[0],
+                                               self.client_address[1]))
         try:
             data = self.get_data()
-            print len(data), data.encode('hex')  # repr(data).replace('\\x', '')[1:-1]
+            print(len(data), data.encode('hex'))  # repr(data).replace('\\x', '')[1:-1]
             self.send_data(dns_response(data))
         except Exception:
             traceback.print_exc(file=sys.stderr)
@@ -118,17 +118,17 @@ def send_data(self, data):
 
 
 if __name__ == '__main__':
-    print "Starting nameserver..."
+    print("Starting nameserver...")
 
     servers = [
-        SocketServer.ThreadingUDPServer(('', PORT), UDPRequestHandler),
-        SocketServer.ThreadingTCPServer(('', PORT), TCPRequestHandler),
+        socketserver.ThreadingUDPServer(('', PORT), UDPRequestHandler),
+        socketserver.ThreadingTCPServer(('', PORT), TCPRequestHandler),
     ]
     for s in servers:
         thread = threading.Thread(target=s.serve_forever)  # that thread will start one more thread for each request
         thread.daemon = True  # exit the server thread when the main thread terminates
         thread.start()
-        print "%s server loop running in thread: %s" % (s.RequestHandlerClass.__name__[:3], thread.name)
+        print("%s server loop running in thread: %s" % (s.RequestHandlerClass.__name__[:3], thread.name))
 
     try:
         while 1:

diff --git a/...r (UDP and TCP) in Python using dnslib.py → ddnsserver.py b/...r (UDP and TCP) in Python using dnslib.py → ddnsserver.py
@@ -1,4 +1,6 @@
+#!/usr/bin/env python
 # coding=utf-8
+
 import datetime
 import sys
 import time

diff --git a/Python simple DNS server with dnslib.py → ...r (UDP and TCP) in Python using dnslib.py b/Python simple DNS server with dnslib.py → ...r (UDP and TCP) in Python using dnslib.py
diff --git a/Python simple DNS server with dnslib.py b/Python simple DNS server with dnslib.py
@@ -65,8 +65,7 @@ def dns_response(data):
 
         reply.add_ns(RR(rname=D, rtype=QTYPE.SOA, rclass=1, ttl=TTL, rdata=soa_record))
 
-    print "---- Reply"
-    print reply
+    print "---- Reply:\n", reply
 
     return reply.pack()
 
@@ -81,7 +80,7 @@ def send_data(self, data):
 
     def handle(self):
         now = datetime.datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')
-        print "---- %s request %s (%s %s):" % (self.__class__.__name__[:3], now, self.client_address[0],
+        print "\n\n%s request %s (%s %s):" % (self.__class__.__name__[:3], now, self.client_address[0],
                                                self.client_address[1])
         try:
             data = self.get_data()

diff --git a/Python simple DNS server with dnslib.py b/Python simple DNS server with dnslib.py
@@ -94,10 +94,17 @@ def handle(self):
 class TCPRequestHandler(BaseRequestHandler):
 
     def get_data(self):
-        return self.request.recv(8192).strip()[2:]
+        data = self.request.recv(8192).strip()
+        sz = int(data[:2].encode('hex'), 16)
+        if sz < len(data) - 2:
+            raise Exception("Wrong size of TCP packet")
+        elif sz > len(data) - 2:
+            raise Exception("Too big TCP packet")
+        return data[2:]
 
     def send_data(self, data):
-        return self.request.sendall(data)
+        sz = hex(len(data))[2:].zfill(4).decode('hex')
+        return self.request.sendall(sz + data)
 
 
 class UDPRequestHandler(BaseRequestHandler):
@@ -125,6 +132,9 @@ def send_data(self, data):
     try:
         while 1:
             time.sleep(1)
+            sys.stderr.flush()
+            sys.stdout.flush()
+
     except KeyboardInterrupt:
         pass
     finally:

diff --git a/Python simple DNS server with dnslib.py b/Python simple DNS server with dnslib.py
@@ -1,6 +1,7 @@
 # coding=utf-8
 import datetime
 import sys
+import time
 import threading
 import traceback
 import SocketServer
@@ -123,7 +124,7 @@ def send_data(self, data):
 
     try:
         while 1:
-            pass
+            time.sleep(1)
     except KeyboardInterrupt:
         pass
     finally:

diff --git a/Python simple DNS server with dnslib.py b/Python simple DNS server with dnslib.py
@@ -1,5 +1,9 @@
 # coding=utf-8
-import socket
+import datetime
+import sys
+import threading
+import traceback
+import SocketServer
 from dnslib import *
 
 
@@ -11,6 +15,7 @@ def __getattr__(self, item):
 D = DomainName('example.com')
 IP = '127.0.0.1'
 TTL = 60 * 5
+PORT = 5053
 
 soa_record = SOA(
     mname=D.ns1,  # primary name server
@@ -31,7 +36,6 @@ def __getattr__(self, item):
     D.mail: [A(IP)],
     D.andrei: [CNAME(D)],
 }
-# TODO: DNSKEY, RRSIG
 
 
 def dns_response(data):
@@ -66,25 +70,62 @@ def dns_response(data):
     return reply.pack()
 
 
+class BaseRequestHandler(SocketServer.BaseRequestHandler):
+
+    def get_data(self):
+        raise NotImplementedError
+
+    def send_data(self, data):
+        raise NotImplementedError
+
+    def handle(self):
+        now = datetime.datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')
+        print "---- %s request %s (%s %s):" % (self.__class__.__name__[:3], now, self.client_address[0],
+                                               self.client_address[1])
+        try:
+            data = self.get_data()
+            print len(data), data.encode('hex')  # repr(data).replace('\\x', '')[1:-1]
+            self.send_data(dns_response(data))
+        except Exception:
+            traceback.print_exc(file=sys.stderr)
+
+
+class TCPRequestHandler(BaseRequestHandler):
+
+    def get_data(self):
+        return self.request.recv(8192).strip()[2:]
+
+    def send_data(self, data):
+        return self.request.sendall(data)
+
+
+class UDPRequestHandler(BaseRequestHandler):
+
+    def get_data(self):
+        return self.request[0].strip()
+
+    def send_data(self, data):
+        return self.request[1].sendto(data, self.client_address)
+
+
 if __name__ == '__main__':
     print "Starting nameserver..."
 
-    udps = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-    udps.bind(('', 5053))
+    servers = [
+        SocketServer.ThreadingUDPServer(('', PORT), UDPRequestHandler),
+        SocketServer.ThreadingTCPServer(('', PORT), TCPRequestHandler),
+    ]
+    for s in servers:
+        thread = threading.Thread(target=s.serve_forever)  # that thread will start one more thread for each request
+        thread.daemon = True  # exit the server thread when the main thread terminates
+        thread.start()
+        print "%s server loop running in thread: %s" % (s.RequestHandlerClass.__name__[:3], thread.name)
 
     try:
         while 1:
-            print "\nWaiting for query...\n"
-            data, addr = udps.recvfrom(8192)
-
-            try:
-                print "---- Request (%s %s):" % tuple(addr)
-                udps.sendto(dns_response(data), addr)
-
-            except:
-                import sys
-                import traceback
-                traceback.print_exc(file=sys.stderr)
-
+            pass
     except KeyboardInterrupt:
-        udps.close()
+        pass
+    finally:
+        for s in servers:
+            s.shutdown()
diff --git a/Python simple DNS server with dnslib.py b/Python simple DNS server with dnslib.py
@@ -82,8 +82,9 @@ def dns_response(data):
                 udps.sendto(dns_response(data), addr)
 
             except:
+                import sys
                 import traceback
-                traceback.print_exc()
+                traceback.print_exc(file=sys.stderr)
 
     except KeyboardInterrupt:
         udps.close()
diff --git a/Python simple DNS server with dnslib.py b/Python simple DNS server with dnslib.py
@@ -0,0 +1,89 @@
+# coding=utf-8
+import socket
+from dnslib import *
+
+
+class DomainName(str):
+    def __getattr__(self, item):
+        return DomainName(item + '.' + self)
+
+
+D = DomainName('example.com')
+IP = '127.0.0.1'
+TTL = 60 * 5
+
+soa_record = SOA(
+    mname=D.ns1,  # primary name server
+    rname=D.andrei,  # email of the domain administrator
+    times=(
+        201307231,  # serial number
+        60 * 60 * 1,  # refresh
+        60 * 60 * 3,  # retry
+        60 * 60 * 24,  # expire
+        60 * 60 * 1,  # minimum
+    )
+)
+ns_records = [NS(D.ns1), NS(D.ns2)]
+records = {
+    D: [A(IP), AAAA((0,) * 16), MX(D.mail), soa_record] + ns_records,
+    D.ns1: [A(IP)],  # MX and NS records must never point to a CNAME alias (RFC 2181 section 10.3)
+    D.ns2: [A(IP)],
+    D.mail: [A(IP)],
+    D.andrei: [CNAME(D)],
+}
+# TODO: DNSKEY, RRSIG
+
+
+def dns_response(data):
+    request = DNSRecord.parse(data)
+
+    print request
+
+    reply = DNSRecord(DNSHeader(id=request.header.id, qr=1, aa=1, ra=1), q=request.q)
+
+    qname = request.q.qname
+    qn = str(qname)
+    qtype = request.q.qtype
+    qt = QTYPE[qtype]
+
+    if qn == D or qn.endswith('.' + D):
+
+        for name, rrs in records.iteritems():
+            if name == qn:
+                for rdata in rrs:
+                    rqt = rdata.__class__.__name__
+                    if qt in ['*', rqt]:
+                        reply.add_answer(RR(rname=qname, rtype=QTYPE[rqt], rclass=1, ttl=TTL, rdata=rdata))
+
+        for rdata in ns_records:
+            reply.add_ns(RR(rname=D, rtype=QTYPE.NS, rclass=1, ttl=TTL, rdata=rdata))
+
+        reply.add_ns(RR(rname=D, rtype=QTYPE.SOA, rclass=1, ttl=TTL, rdata=soa_record))
+
+    print "---- Reply"
+    print reply
+
+    return reply.pack()
+
+
+if __name__ == '__main__':
+    print "Starting nameserver..."
+
+    udps = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    udps.bind(('', 5053))
+
+    try:
+        while 1:
+            print "\nWaiting for query...\n"
+            data, addr = udps.recvfrom(8192)
+
+            try:
+                print "---- Request (%s %s):" % tuple(addr)
+                udps.sendto(dns_response(data), addr)
+
+            except:
+                import traceback
+                traceback.print_exc()
+
+    except KeyboardInterrupt:
+        udps.close()