ipreversedns.py 文件源码

def evaluate(self,
                 hints  # Information used for doing identification
                 ):

        """Given a set of hints, evaluate this identifier and return True if
        an identification is made.

        """

        try:
            ip = hints['requester']
        except KeyError:
            return False

        addr = ipaddr.IPAddress(ip)

        ip_reverse = dns.reversename.from_address(ip)

        # Resolve to a FQDN

        try:
            reverse = str(self.resolver.query(ip_reverse, 'PTR')[0])
        except (dns.resolver.NXDOMAIN,
                dns.exception.Timeout,
                dns.resolver.NoAnswer,
                dns.resolver.NoNameservers):
            return False

        # Resolve the FQDN back to an IP and see if they match.  This
        # prevents someone in control over their reverse resolution
        # from claiming they're someone they're not.

        # TODO: Check against _all_ returned IPs

        record = 'A' if addr.version == 4 else 'AAAA'
        try:
            forwards = self.resolver.query(reverse, record)
        except (dns.resolver.NXDOMAIN,
                dns.exception.Timeout,
                dns.resolver.NoAnswer,
                dns.resolver.NoNameservers):
            return False

        if ip not in [ str(f) for f in forwards ]:
            return False

        # Try to match with and without the dot at the end.

        for reverse_candidate in [ reverse, reverse.rstrip('.') ]:
            if self.matcher.matches(reverse_candidate):
                return True


        # No match, no dice.
        return False



# A short test program