diff options
Diffstat (limited to 'trunk/ipaddr.py')
| -rw-r--r-- | trunk/ipaddr.py | 194 |
1 files changed, 80 insertions, 114 deletions
diff --git a/trunk/ipaddr.py b/trunk/ipaddr.py index 30768d9..c9aee63 100644 --- a/trunk/ipaddr.py +++ b/trunk/ipaddr.py @@ -839,8 +839,8 @@ class _BaseNet(_IPAddrBase): """ return (self._version, self.network, self.netmask) - def _ip_int_from_prefix(self, prefixlen=None): - """Turn the prefix length netmask into a int for comparison. + def _ip_int_from_prefix(self, prefixlen): + """Turn the prefix length into a bitwise netmask. Args: prefixlen: An integer, the prefix length. @@ -849,42 +849,90 @@ class _BaseNet(_IPAddrBase): An integer. """ - if not prefixlen and prefixlen != 0: - prefixlen = self._prefixlen return self._ALL_ONES ^ (self._ALL_ONES >> prefixlen) - def _prefix_from_ip_int(self, ip_int, mask=32): - """Return prefix length from the decimal netmask. + def _prefix_from_ip_int(self, ip_int): + """Return prefix length from a bitwise netmask. Args: - ip_int: An integer, the IP address. - mask: The netmask. Defaults to 32. + ip_int: An integer, the netmask in expanded bitwise format. Returns: An integer, the prefix length. + Raises: + NetmaskValueError: If the input is not a valid netmask. + """ - while mask: - if ip_int & 1 == 1: + prefixlen = self._max_prefixlen + while prefixlen: + if ip_int & 1: break ip_int >>= 1 - mask -= 1 + prefixlen -= 1 + + if ip_int == (1 << prefixlen) - 1: + return prefixlen + else: + raise NetmaskValueError('Bit pattern does not match /1*0*/') + + def _prefix_from_prefix_string(self, prefixlen_str): + """Turn a prefix length string into an integer. + + Args: + prefixlen_str: A decimal string containing the prefix length. + + Returns: + The prefix length as an integer. - return mask + Raises: + NetmaskValueError: If the input is malformed or out of range. + + """ + try: + if not _BaseV4._DECIMAL_DIGITS.issuperset(prefixlen_str): + raise ValueError + prefixlen = int(prefixlen_str) + if not (0 <= prefixlen <= self._max_prefixlen): + raise ValueError + except ValueError: + raise NetmaskValueError('%s is not a valid prefix length' % + prefixlen_str) + return prefixlen - def _ip_string_from_prefix(self, prefixlen=None): - """Turn a prefix length into a dotted decimal string. + def _prefix_from_ip_string(self, ip_str): + """Turn a netmask/hostmask string into a prefix length. Args: - prefixlen: An integer, the netmask prefix length. + ip_str: A netmask or hostmask, formatted as an IP address. Returns: - A string, the dotted decimal netmask string. + The prefix length as an integer. + + Raises: + NetmaskValueError: If the input is not a netmask or hostmask. """ - if not prefixlen: - prefixlen = self._prefixlen - return self._string_from_ip_int(self._ip_int_from_prefix(prefixlen)) + # Parse the netmask/hostmask like an IP address. + try: + ip_int = self._ip_int_from_string(ip_str) + except AddressValueError: + raise NetmaskValueError('%s is not a valid netmask' % ip_str) + + # Try matching a netmask (this would be /1*0*/ as a bitwise regexp). + # Note that the two ambiguous cases (all-ones and all-zeroes) are + # treated as netmasks. + try: + return self._prefix_from_ip_int(ip_int) + except NetmaskValueError: + pass + + # Invert the bits, and try matching a /0+1+/ hostmask instead. + ip_int ^= self._ALL_ONES + try: + return self._prefix_from_ip_int(ip_int) + except NetmaskValueError: + raise NetmaskValueError('%s is not a valid netmask' % ip_str) def iter_subnets(self, prefixlen_diff=1, new_prefix=None): """The subnets which join to make the current subnet. @@ -927,7 +975,7 @@ class _BaseNet(_IPAddrBase): raise ValueError('prefix length diff must be > 0') new_prefixlen = self._prefixlen + prefixlen_diff - if not self._is_valid_netmask(str(new_prefixlen)): + if new_prefixlen > self._max_prefixlen: raise ValueError( 'prefix length diff %d is invalid for netblock %s' % ( new_prefixlen, str(self))) @@ -1227,9 +1275,6 @@ class IPv4Network(_BaseV4, _BaseNet): """ - # the valid octets for host and netmasks. only useful for IPv4. - _valid_mask_octets = set((255, 254, 252, 248, 240, 224, 192, 128, 0)) - def __init__(self, address, strict=False): """Instantiate a new IPv4 network object. @@ -1292,31 +1337,18 @@ class IPv4Network(_BaseV4, _BaseNet): self.ip = IPv4Address(self._ip) if len(addr) == 2: - mask = addr[1].split('.') - if len(mask) == 4: - # We have dotted decimal netmask. - if self._is_valid_netmask(addr[1]): - self.netmask = IPv4Address(self._ip_int_from_string( - addr[1])) - elif self._is_hostmask(addr[1]): - self.netmask = IPv4Address( - self._ip_int_from_string(addr[1]) ^ self._ALL_ONES) - else: - raise NetmaskValueError('%s is not a valid netmask' - % addr[1]) - - self._prefixlen = self._prefix_from_ip_int(int(self.netmask)) - else: - # We have a netmask in prefix length form. - if not self._is_valid_netmask(addr[1]): - raise NetmaskValueError(addr[1]) - self._prefixlen = int(addr[1]) - self.netmask = IPv4Address(self._ip_int_from_prefix( - self._prefixlen)) + try: + # Check for a netmask in prefix length form. + self._prefixlen = self._prefix_from_prefix_string(addr[1]) + except NetmaskValueError: + # Check for a netmask or hostmask in dotted-quad form. + # This may raise NetmaskValueError. + self._prefixlen = self._prefix_from_ip_string(addr[1]) else: self._prefixlen = self._max_prefixlen - self.netmask = IPv4Address(self._ip_int_from_prefix( - self._prefixlen)) + + self.netmask = IPv4Address(self._ip_int_from_prefix(self._prefixlen)) + if strict: if self.ip != self.network: raise ValueError('%s has host bits set' % @@ -1324,53 +1356,6 @@ class IPv4Network(_BaseV4, _BaseNet): if self._prefixlen == (self._max_prefixlen - 1): self.iterhosts = self.__iter__ - def _is_hostmask(self, ip_str): - """Test if the IP string is a hostmask (rather than a netmask). - - Args: - ip_str: A string, the potential hostmask. - - Returns: - A boolean, True if the IP string is a hostmask. - - """ - bits = ip_str.split('.') - try: - parts = [int(x) for x in bits if int(x) in self._valid_mask_octets] - except ValueError: - return False - if len(parts) != len(bits): - return False - if parts[0] < parts[-1]: - return True - return False - - def _is_valid_netmask(self, netmask): - """Verify that the netmask is valid. - - Args: - netmask: A string, either a prefix or dotted decimal - netmask. - - Returns: - A boolean, True if the prefix represents a valid IPv4 - netmask. - - """ - mask = netmask.split('.') - if len(mask) == 4: - if [x for x in mask if int(x) not in self._valid_mask_octets]: - return False - if [y for idx, y in enumerate(mask) if idx > 0 and - y > mask[idx - 1]]: - return False - return True - try: - netmask = int(netmask) - except ValueError: - return False - return 0 <= netmask <= self._max_prefixlen - # backwards compatibility IsRFC1918 = lambda self: self.is_private IsMulticast = lambda self: self.is_multicast @@ -1861,10 +1846,8 @@ class IPv6Network(_BaseV6, _BaseNet): self.ip = IPv6Address(self._ip) if len(addr) == 2: - if self._is_valid_netmask(addr[1]): - self._prefixlen = int(addr[1]) - else: - raise NetmaskValueError(addr[1]) + # This may raise NetmaskValueError + self._prefixlen = self._prefix_from_prefix_string(addr[1]) else: self._prefixlen = self._max_prefixlen @@ -1877,23 +1860,6 @@ class IPv6Network(_BaseV6, _BaseNet): if self._prefixlen == (self._max_prefixlen - 1): self.iterhosts = self.__iter__ - def _is_valid_netmask(self, prefixlen): - """Verify that the netmask/prefixlen is valid. - - Args: - prefixlen: A string, the netmask in prefix length format. - - Returns: - A boolean, True if the prefix represents a valid IPv6 - netmask. - - """ - try: - prefixlen = int(prefixlen) - except ValueError: - return False - return 0 <= prefixlen <= self._max_prefixlen - @property def with_netmask(self): return self.with_prefixlen |