resolve domains directly against dyn nameserver (instead of system resolver)

[dyn-nsupdate.git] / client-scripts / dyn-ns-client

diff --git a/client-scripts/dyn-ns-client b/client-scripts/dyn-ns-client
index af263b76aca5111812a19a38ffbcc4f6b9714c23..124498a8d6940133bf3ab043fa1308502af3a7b8 100755 (executable)
--- a/client-scripts/dyn-ns-client
+++ b/client-scripts/dyn-ns-client
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3

 # Copyright (c) 2014, Ralf Jung <post@ralfj.de>
 # All rights reserved.
 # 
 # Copyright (c) 2014, Ralf Jung <post@ralfj.de>
 # All rights reserved.
 # 


@@ -23,7 +23,18 @@
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #==============================================================================
 
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #==============================================================================
 

-import urllib.request, socket, sys, argparse, os, configparser, itertools
+import urllib.request, socket, sys, argparse, os, configparser, itertools, subprocess, re, ssl
+import dns, dns.resolver
+
+VERBOSE_CHANGE = 1
+VERBOSE_FULL   = 2
+
+def sslContext(config):
+    if config['DEFAULT'].get('ssl_check_cert', 'yes').lower() in ('0', 'false', 'no'):
+        context = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
+        return context
+    else:
+        return None

 
 def readConfig(fname, defSection = 'DEFAULT'):
     config = configparser.ConfigParser()
 
 def readConfig(fname, defSection = 'DEFAULT'):
     config = configparser.ConfigParser()


@@ -39,66 +50,90 @@ def getConfigDir():
     except ImportError:
         return os.path.expanduser("~/.config/dyn-nsupdate")
 
     except ImportError:
         return os.path.expanduser("~/.config/dyn-nsupdate")
 

-def urlopen(url):
-    return urllib.request.urlopen(url).read().decode('utf-8').strip()
+def urlopen(url, config):
+    if sys.version_info >= (3, 4, 3):
+        return urllib.request.urlopen(url, context=sslContext(config)).read().decode('utf-8').strip('\n')
+    else:
+        return urllib.request.urlopen(url).read().decode('utf-8').strip('\n')

 
 

-def getMyIP(family, config, methods = {}, verbose = False):
+def getMyIP(family, config, methods = {}, verbose = 0):

     '''Returns our current IP address (<family> can be "IPv4" or "IPv6"), detected as given by the configuration.
        Additional detection methods can be supplied via <methods>.'''
     method = config[family]['method']
     if method == 'none':
         return None
     '''Returns our current IP address (<family> can be "IPv4" or "IPv6"), detected as given by the configuration.
        Additional detection methods can be supplied via <methods>.'''
     method = config[family]['method']
     if method == 'none':
         return None

+    elif method == 'remove':
+        return ""

     elif method == 'web':
         server = config[family].get('server', config['DEFAULT']['server'])
     elif method == 'web':
         server = config[family].get('server', config['DEFAULT']['server'])

-        ip = urlopen('https://'+server+'/checkip')
-        if verbose:
+        url = 'https://'+server+'/checkip'
+        try:
+            ip = urlopen(url, config)
+        except urllib.error.URLError:
+            raise Exception("Error fetching {}, make sure the URL is correct and the internet connection actually works.".format(url))
+        if verbose >= VERBOSE_FULL:

             print("Server",server,"says my",family,"is",ip)
         return ip
             print("Server",server,"says my",family,"is",ip)
         return ip

-    elif method in 'methods':
+    elif method in methods:

         return methods[method]()
     else:
         raise Exception("Unsupported "+family+" detection method: "+method)
 
         return methods[method]()
     else:
         raise Exception("Unsupported "+family+" detection method: "+method)
 

-def getMyIPv4(config, verbose = False):
+def getMyIPv4(config, verbose = 0):

     '''Returns our current IPv4 address, detected as given by the configuration'''
     return getMyIP("IPv4", config, verbose=verbose)
 
     '''Returns our current IPv4 address, detected as given by the configuration'''
     return getMyIP("IPv4", config, verbose=verbose)
 

-def getMyIPv6(config, verbose = False):
+def getMyIPv6(config, verbose = 0):

     '''Returns our current IPv6 address, detected as given by the configuration'''
     '''Returns our current IPv6 address, detected as given by the configuration'''

-    return getMyIP("IPv6", config, verbose=verbose)
+    def local():
+        device = config["IPv6"].get("device")
+        out = subprocess.check_output(["ip", "addr", "show"] + ([] if device is None else ["dev", device]))
+        for line in out.decode('utf-8').split('\n'):
+            m = re.search('inet6 ([a-fA-F0-9:]+)/64 ([a-zA-Z0-9 ]*)', line)
+            if m is not None:
+                ip = m.group(1)
+                flags = m.group(2).split()
+                if not 'temporary' in flags and not 'deprecated' in flags and not "link" in flags:
+                    if verbose >= VERBOSE_FULL:
+                        print("Local IPv6 detected to be",ip)
+                    return ip
+        raise Exception("Unable to detect correct local IPv6 address")
+    return getMyIP("IPv6", config, methods={'local': local}, verbose=verbose)
+
+def getResolver(server):
+    '''Return a resovler with the given server (defined by DNS name)'''
+    addr = socket.getaddrinfo(server, None, family=socket.AF_INET)
+    addr = addr[0][4][0]
+    res = dns.resolver.Resolver()
+    res.nameservers = [addr]
+    return res

 
 

-def getCurIP(domain, family):
-    '''Return the current IP of the given <domain>. <family> can be socket.AF_INET or socket.AF_INET6.'''
+def getCurIP(domain, rtype, res):
+    '''Return the current IP of the given <domain>. <rtype> can be A or AAAA.'''

     try:
     try:

-        addr = socket.getaddrinfo(domain, None, family=family)
-        return addr[0][4][0]
-    except socket.gaierror: # domain not found
+        return res.query(domain, rtype)[0].address
+    except dns.exception.DNSException: # domain not found

         return ""
 
         return ""
 

-def getCurIPv4(domain):
-    '''Returns the current IPv4 address of the given domain'''
-    return getCurIP(domain, socket.AF_INET)
-
-def getCurIPv6(domain):
-    '''Returns the current IPv6 address of the given domain'''
-    return getCurIP(domain, socket.AF_INET6)
-
-def updateDomain(server, domain, ipv4, ipv6, password, verbose):
+def updateDomain(server, domain, ipv4, ipv6, password, config, verbose):

     '''Update the given domain, using the server, password. ipv4 or ipv6 can be None to not update that record, or strings with the respective addresses.
        Updates ae only performed if necessary.
        Returns True on success, False on failure.'''
     assert ipv4 is not None or ipv6 is not None
     
     # check what the domain is currently mapped to
     '''Update the given domain, using the server, password. ipv4 or ipv6 can be None to not update that record, or strings with the respective addresses.
        Updates ae only performed if necessary.
        Returns True on success, False on failure.'''
     assert ipv4 is not None or ipv6 is not None
     
     # check what the domain is currently mapped to

-    curIPv4 = getCurIPv4(domain)
-    curIPv6 = getCurIPv6(domain)
-    if verbose:
-        print("Current status of domain {0} is: IPv4 address '{1}', IPv6 address '{2}'".format(domain, curIPv4, curIPv6))
+    res = getResolver(server)
+    if verbose >= VERBOSE_FULL:
+        print("Resolving names using {}".format(res.nameservers))
+    curIPv4 = getCurIP(domain, 'A', res)
+    curIPv6 = getCurIP(domain, 'AAAA', res)
+    if verbose >= VERBOSE_FULL:
+        print("Current status of domain {} is: IPv4 address '{}', IPv6 address '{}'".format(domain, curIPv4, curIPv6))

     
     # check if there's something to do
     needUpdate = (ipv4 is not None and curIPv4 != ipv4) or (ipv6 is not None and curIPv6 != ipv6)
     if not needUpdate:
     
     # check if there's something to do
     needUpdate = (ipv4 is not None and curIPv4 != ipv4) or (ipv6 is not None and curIPv6 != ipv6)
     if not needUpdate:

-        if verbose:
+        if verbose >= VERBOSE_FULL:

             print("Everything already up-to-date, nothing to do")
         return True
 
             print("Everything already up-to-date, nothing to do")
         return True
 


@@ -111,18 +146,33 @@ def updateDomain(server, domain, ipv4, ipv6, password, verbose):
     if ipv6 is not None:
         url += '&ipv6='+urllib.parse.quote(ipv6)
         expected += " "+ipv6
     if ipv6 is not None:
         url += '&ipv6='+urllib.parse.quote(ipv6)
         expected += " "+ipv6

-    result = urlopen(url)
+    if verbose >= VERBOSE_FULL:
+        print("Request:",url)
+    result = urlopen(url, config)

     
     # did everything go as planned?
     if result == expected:
     
     # did everything go as planned?
     if result == expected:

-        if verbose:
-            print("Successfully updated domain",domain,"on",server)
+        if verbose >= VERBOSE_CHANGE:
+            msg = "Successfully updated domain {} on {}:".format(domain, server)
+            if ipv4 is not None:
+                if curIPv4 == ipv4:
+                    msg += " IPv4={} (unchanged)".format(curIPv4)
+                else:
+                    msg += " IPv4={} -> {}".format(curIPv4, ipv4)
+            if ipv4 is not None and ipv6 is not None:
+                msg += ","
+            if ipv6 is not None:
+                if curIPv6 == ipv6:
+                    msg += " IPv6={} (unchanged)".format(curIPv6)
+                else:
+                    msg += " IPv6={} -> {}".format(curIPv6, ipv6)
+            print(msg)

         # all went all right
         return True
     else:
         # Something went wrong
         print("Unexpected answer from server",server,"while updating",domain)
         # all went all right
         return True
     else:
         # Something went wrong
         print("Unexpected answer from server",server,"while updating",domain)

-        print(result)
+        print("Got '{}', expected '{}'".format(result, expected))

         return False
 
 if __name__ == "__main__":
         return False
 
 if __name__ == "__main__":


@@ -132,7 +182,7 @@ if __name__ == "__main__":
                         dest="config", default=os.path.join(getConfigDir(), "dyn-ns-client.conf"),
                         help="The configuration file")
     parser.add_argument("-v", "--verbose",
                         dest="config", default=os.path.join(getConfigDir(), "dyn-ns-client.conf"),
                         help="The configuration file")
     parser.add_argument("-v", "--verbose",

-                        action="store_true", dest="verbose",
+                        action="count", dest="verbose", default=0,

                         help="Be more verbose")
     args = parser.parse_args()
     
                         help="Be more verbose")
     args = parser.parse_args()
     


@@ -151,6 +201,6 @@ if __name__ == "__main__":
     if not domains:
         raise Exception("No domain given to update!")
     for domain in domains:
     if not domains:
         raise Exception("No domain given to update!")
     for domain in domains:

-        if not updateDomain(config['DEFAULT']['server'], domain, myIPv4, myIPv6, config['DEFAULT']['password'], verbose=args.verbose):
+        if not updateDomain(config['DEFAULT']['server'], domain, myIPv4, myIPv6, config['DEFAULT']['password'], config, verbose=args.verbose):

             exitcode = 1
     sys.exit(exitcode)
             exitcode = 1
     sys.exit(exitcode)