X-Git-Url: https://git.toastfreeware.priv.at/toast/tdyndns.git/blobdiff_plain/89d757f016b07ca7a40ad45d6568973a2dcda2d5..HEAD:/bin/tdyndns_update

diff --git a/bin/tdyndns_update b/bin/tdyndns_update
index b43286e..8806c8a 100755
--- a/bin/tdyndns_update
+++ b/bin/tdyndns_update
@@ -1,19 +1,15 @@
 #!/usr/bin/python
+import os
 import sys
 import re
 import argparse
-from subprocess import Popen, PIPE
+from subprocess import Popen, PIPE, check_call, CalledProcessError
 import ipaddr
+import dns.zone  # http://www.dnspython.org/
 
 
-class NsupdateError(Exception):
-	def __init__(self, returncode):
-		self.returncode = returncode
-
-
-class BlockipError(Exception):
-	def __init__(self, returncode):
-		self.returncode = returncode
+def sync_dynamic_zones():
+	check_call(['rndc', 'sync'])
 
 
 def ipfamily_by_ip(ip):
@@ -24,49 +20,72 @@ def ipfamily_by_ip(ip):
 	assert False
 
 
+def forward_lookup(fqdn, ip_family):
+	"""Returns the ip address of the fqdn or None if none is found..
+
+	:param fqdn: Fully qualified domain name.
+	:param ip_family: 'A' or 'AAAA'"""
+	filename = '/var/cache/bind/dyn.colgarra.priv.at'
+	zonename = os.path.basename(filename)
+	zone = dns.zone.from_file(filename, zonename, relativize=False)
+	for name, ttl, rdata in zone.iterate_rdatas(ip_family):
+		if str(name)[:-1] == fqdn:  # [:-1] removes trailing dot
+			return ipaddr.IPAddress(rdata.address)
+
+
+def reverse_lookup(ip):
+	"""Returns an iterator of fqdns for the given IP address.
+
+	:param ip: Instance of ipaddr.IPv4Address or ipaddr.IPv6Address"""
+	filename = '/var/cache/bind/dyn.colgarra.priv.at'
+	zonename = os.path.basename(filename)
+	zone = dns.zone.from_file(filename, zonename, relativize=False)
+	for name, ttl, rdata in zone.iterate_rdatas(ipfamily_by_ip(ip)):
+		if ipaddr.IPAddress(rdata.address) == ip:
+			yield str(name)
+
+
 def nsupdate_add(fqdn, ttl, ip):
 	"""
 	:param fqdn: Fully qualified domain name
 	:param ip_family: A or AAAA
-	:raises an NsupdateError in case of errors."""
+	:raises an CalledProcessError in case of errors."""
 	command = "update add {fqdn} {ttl} IN {ip_family} {ip}\n\n".format(fqdn=fqdn, ttl=ttl, ip_family=ipfamily_by_ip(ip), ip=ip)
 	p = Popen(['nsupdate', '-l'], stdin=PIPE)
 	p.communicate(command)
 	if p.returncode != 0:
-		raise NsupdateError(p.returncode)
+		raise CalledProcessError(p.returncode, 'nsupdate -l')
 
 def nsupdate_delete(fqdn, ip_family):
 	"""
 	:param fqdn: Fully qualified domain name
 	:param ip_family: A or AAAA
-	:raises an NsupdateError in case of errors."""
+	:raises an CalledProcessError in case of errors."""
 	command = "update delete {fqdn} {ip_family}\n\n".format(fqdn=fqdn, ip_family=ip_family)
 	p = Popen(['nsupdate', '-l'], stdin=PIPE)
 	p.communicate(command)
 	if p.returncode != 0:
-		raise NsupdateError(p.returncode)
+		raise CalledProcessError(p.returncode, 'nsupdate -l')
 
 
 def blockip_whitelist_add(ip):
 	"""
 	:param ip: ipv4 address
-	:raises a BlockipError in case of errors."""
-	command = "-I blockip -s {ip} -j ACCEPT\n\n".format(ip=ip)
-	p = Popen(['iptables'], stdin=PIPE)
-	p.communicate(command)
-	if p.returncode != 0:
-		raise NsupdateError(p.returncode)
+	"""
+	if ipfamily_by_ip(ip) == 'A':
+		command = ['iptables', '-I', 'blockip', '-s', str(ip), '-j', 'ACCEPT']
+		p = Popen(command, stderr=PIPE)
+		stdout, stderr = p.communicate()
 
 
 def blockip_whitelist_delete(ip):
 	"""
 	:param ip: ipv4 address
-	:raises a BlockipError in case of errors."""
-	command = "-D blockip -s {ip} -j ACCEPT\n\n".format(ip=ip)
-	p = Popen(['iptables'], stdin=PIPE)
-	p.communicate(command)
-	if p.returncode != 0:
-		raise NsupdateError(p.returncode)
+	"""
+	if ipfamily_by_ip(ip) == 'A':
+		command = ['iptables', '-D', 'blockip', '-s', str(ip), '-j', 'ACCEPT']
+		p = Popen(command, stderr=PIPE)
+		stdout, stderr = p.communicate()
 
 
 def main(args):
@@ -76,15 +95,23 @@ def main(args):
 				nsupdate_delete(args.fqdn, 'A')
 				nsupdate_delete(args.fqdn, 'AAAA')
 			else:
+				ipfamily = ipfamily_by_ip(args.ip)
+				sync_dynamic_zones()
+				old_ip = forward_lookup(args.fqdn, ipfamily)
 				nsupdate_delete(args.fqdn, ipfamily_by_ip(args.ip))
-				if ipfamily_by_ip(args.ip) == 'A':
-					blockip_whitelist_delete(args.ip)
+				if old_ip is not None:
+					blockip_whitelist_delete(old_ip)
 		else:
-			nsupdate_delete(args.fqdn, ipfamily_by_ip(args.ip))
+			ipfamily = ipfamily_by_ip(args.ip)
+			sync_dynamic_zones()
+			old_ip = forward_lookup(args.fqdn, ipfamily)
+			nsupdate_delete(args.fqdn, ipfamily)
 			nsupdate_add(args.fqdn, args.ttl, args.ip)
-			if ipfamily_by_ip(args.ip) == 'A':
+			if old_ip != args.ip:
+				if old_ip is not None:
+					blockip_whitelist_delete(old_ip)
 				blockip_whitelist_add(args.ip)
-	except NsupdateError as e:
+	except CalledProcessError as e:
 		sys.exit(e.returncode)