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 0fc88e6fc978f3195f4c2d4b6b4e1740c930fd0d..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.
 # 


@@ -21,59 +21,120 @@
 # ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 # ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

-# 
-# The views and conclusions contained in the software and documentation are those
-# of the authors and should not be interpreted as representing official policies, 
-# either expressed or implied, of the FreeBSD Project.
-#==============================================================================
-# configuration variables
-domains = ['test.dyn.example.com'] # list of domains to update
-password = 'some_secure_password'
-haveIPv4 = True
-haveIPv6 = False
-
-serverIPv4 = 'ipv4.ns.example.com' # Only needed if haveIPv4 is True. This server should NOT have an AAAA record!
-serverIPv6 = 'ipv6.ns.example.com' # Only needed if haveIPv6 is True. This server should NOT have an A record!
-server     = 'ns.example.com'
-# END of configuration variables

 #==============================================================================
 
 #==============================================================================
 

-import urllib.request, socket, sys, argparse
+import urllib.request, socket, sys, argparse, os, configparser, itertools, subprocess, re, ssl
+import dns, dns.resolver

 
 

-def urlopen(url):
-    return urllib.request.urlopen(url).read().decode('utf-8').strip()
+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 getMyIP(server):
-    return urlopen('https://'+server+'/checkip')
+def readConfig(fname, defSection = 'DEFAULT'):
+    config = configparser.ConfigParser()
+    with open(fname) as file:
+        stream = itertools.chain(("["+defSection+"]\n",), file)
+        config.read_file(stream)
+    return config

 
 

-def getCurIP(domain, family):
+def getConfigDir():

     try:
     try:

-        addr = socket.getaddrinfo(domain, None, family=family)
-        return addr[0][4][0]
-    except socket.gaierror: # domain not found
+        from xdg import BaseDirectory
+        return os.path.join(BaseDirectory.xdg_config_home, "dyn-nsupdate")
+    except ImportError:
+        return os.path.expanduser("~/.config/dyn-nsupdate")
+
+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 = 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
+    elif method == 'remove':

         return ""
         return ""

+    elif method == 'web':
+        server = config[family].get('server', config['DEFAULT']['server'])
+        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
+    elif method in methods:
+        return methods[method]()
+    else:
+        raise Exception("Unsupported "+family+" detection method: "+method)

 
 

-def getCurIPv4(domain):
-    return getCurIP(domain, socket.AF_INET)
+def getMyIPv4(config, verbose = 0):
+    '''Returns our current IPv4 address, detected as given by the configuration'''
+    return getMyIP("IPv4", config, verbose=verbose)

 
 

-def getCurIPv6(domain):
-    return getCurIP(domain, socket.AF_INET6)
+def getMyIPv6(config, verbose = 0):
+    '''Returns our current IPv6 address, detected as given by the configuration'''
+    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 update_domain(server, domain, ipv4, ipv6, password, verbose):
-    '''Update the given domain, using the server, password. ipv4 or ipv6 can be None to not update that record. Returns True on success, False on failure.'''
+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, rtype, res):
+    '''Return the current IP of the given <domain>. <rtype> can be A or AAAA.'''
+    try:
+        return res.query(domain, rtype)[0].address
+    except dns.exception.DNSException: # domain not found
+        return ""
+
+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
     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:
-            print("Everything alread up-to-date, nothing to do")
+        if verbose >= VERBOSE_FULL:
+            print("Everything already up-to-date, nothing to do")

         return True
 
     # we need to update the IP
         return True
 
     # we need to update the IP


@@ -85,51 +146,61 @@ def update_domain(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)
+        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__":
     # allow overwriting some values on the command-line
     parser = argparse.ArgumentParser(description='Update a domain managed by a dyn-nsupdate server')
         return False
 
 if __name__ == "__main__":
     # allow overwriting some values on the command-line
     parser = argparse.ArgumentParser(description='Update a domain managed by a dyn-nsupdate server')

-    parser.add_argument("-p", "--password",
-                        dest="password", default=password,
-                        help="The password used to update the domains")
+    parser.add_argument("-c", "--config",
+                        dest="config", default=os.path.join(getConfigDir(), "dyn-ns-client.conf"),
+                        help="The configuration file")

     parser.add_argument("-v", "--verbose",
     parser.add_argument("-v", "--verbose",

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

                         help="Be more verbose")
                         help="Be more verbose")

-    parser.add_argument("domains",  metavar='DOMAIN', nargs='*', default=domains,
-                        help="The domains to update")

     args = parser.parse_args()
     args = parser.parse_args()

+    
+    # read config
+    if not os.path.isfile(args.config):
+        raise Exception("The config file does not exist: "+args.config)
+    config = readConfig(args.config)

 
 

-    # get our own IPv4
-    if haveIPv4:
-        myIPv4 = getMyIP(serverIPv4)
-        if args.verbose:
-            print("My IPv4 is",myIPv4)
-    else:
-        myIPv4 = None
-    # and IPv6
-    if haveIPv6:
-        myIPv6 = getMyIP(serverIPv6)
-        if args.verbose:
-            print("My IPv6 is",myIPv6)
-    else:
-        myIPv6 = None
+    # get our own addresses
+    myIPv4 = getMyIPv4(config, args.verbose)
+    myIPv6 = getMyIPv6(config, args.verbose)

 
     # update all the domains
     exitcode = 0
 
     # update all the domains
     exitcode = 0

-    for domain in args.domains:
-        if not update_domain(server, domain, myIPv4, myIPv6, args.password, verbose=args.verbose):
+    domains = map(str.strip, config['DEFAULT']['domains'].split(','))
+    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'], config, verbose=args.verbose):

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