/usr/lib/python3/dist-packages/maxminddb/reader.py is in python3-maxminddb 1.3.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 | """
maxminddb.reader
~~~~~~~~~~~~~~~~
This module contains the pure Python database reader and related classes.
"""
from __future__ import unicode_literals
try:
import mmap
except ImportError:
# pylint: disable=invalid-name
mmap = None
import struct
from maxminddb.compat import byte_from_int, compat_ip_address
from maxminddb.const import MODE_AUTO, MODE_MMAP, MODE_FILE, MODE_MEMORY
from maxminddb.decoder import Decoder
from maxminddb.errors import InvalidDatabaseError
from maxminddb.file import FileBuffer
class Reader(object):
"""
Instances of this class provide a reader for the MaxMind DB format. IP
addresses can be looked up using the ``get`` method.
"""
_DATA_SECTION_SEPARATOR_SIZE = 16
_METADATA_START_MARKER = b"\xAB\xCD\xEFMaxMind.com"
_ipv4_start = None
def __init__(self, database, mode=MODE_AUTO):
"""Reader for the MaxMind DB file format
Arguments:
database -- A path to a valid MaxMind DB file such as a GeoIP2
database file.
mode -- mode to open the database with. Valid mode are:
* MODE_MMAP - read from memory map.
* MODE_FILE - read database as standard file.
* MODE_MEMORY - load database into memory.
* MODE_AUTO - tries MODE_MMAP and then MODE_FILE. Default.
"""
# pylint: disable=redefined-variable-type
if (mode == MODE_AUTO and mmap) or mode == MODE_MMAP:
with open(database, 'rb') as db_file:
self._buffer = mmap.mmap(
db_file.fileno(), 0, access=mmap.ACCESS_READ)
self._buffer_size = self._buffer.size()
elif mode in (MODE_AUTO, MODE_FILE):
self._buffer = FileBuffer(database)
self._buffer_size = self._buffer.size()
elif mode == MODE_MEMORY:
with open(database, 'rb') as db_file:
self._buffer = db_file.read()
self._buffer_size = len(self._buffer)
else:
raise ValueError(
'Unsupported open mode ({0}). Only MODE_AUTO, '
' MODE_FILE, and MODE_MEMORY are support by the pure Python '
'Reader'.format(mode))
metadata_start = self._buffer.rfind(
self._METADATA_START_MARKER, max(0,
self._buffer_size - 128 * 1024))
if metadata_start == -1:
self.close()
raise InvalidDatabaseError('Error opening database file ({0}). '
'Is this a valid MaxMind DB file?'
''.format(database))
metadata_start += len(self._METADATA_START_MARKER)
metadata_decoder = Decoder(self._buffer, metadata_start)
(metadata, _) = metadata_decoder.decode(metadata_start)
self._metadata = Metadata(**metadata) # pylint: disable=bad-option-value
self._decoder = Decoder(self._buffer, self._metadata.search_tree_size +
self._DATA_SECTION_SEPARATOR_SIZE)
self.closed = False
def metadata(self):
"""Return the metadata associated with the MaxMind DB file"""
return self._metadata
def get(self, ip_address):
"""Return the record for the ip_address in the MaxMind DB
Arguments:
ip_address -- an IP address in the standard string notation
"""
address = compat_ip_address(ip_address)
if address.version == 6 and self._metadata.ip_version == 4:
raise ValueError(
'Error looking up {0}. You attempted to look up '
'an IPv6 address in an IPv4-only database.'.format(ip_address))
pointer = self._find_address_in_tree(address)
return self._resolve_data_pointer(pointer) if pointer else None
def _find_address_in_tree(self, ip_address):
packed = bytearray(ip_address.packed)
bit_count = len(packed) * 8
node = self._start_node(bit_count)
for i in range(bit_count):
if node >= self._metadata.node_count:
break
bit = 1 & (packed[i >> 3] >> 7 - (i % 8))
node = self._read_node(node, bit)
if node == self._metadata.node_count:
# Record is empty
return 0
elif node > self._metadata.node_count:
return node
raise InvalidDatabaseError('Invalid node in search tree')
def _start_node(self, length):
if self._metadata.ip_version != 6 or length == 128:
return 0
# We are looking up an IPv4 address in an IPv6 tree. Skip over the
# first 96 nodes.
if self._ipv4_start:
return self._ipv4_start
node = 0
for _ in range(96):
if node >= self._metadata.node_count:
break
node = self._read_node(node, 0)
self._ipv4_start = node
return node
def _read_node(self, node_number, index):
base_offset = node_number * self._metadata.node_byte_size
record_size = self._metadata.record_size
if record_size == 24:
offset = base_offset + index * 3
node_bytes = b'\x00' + self._buffer[offset:offset + 3]
elif record_size == 28:
(middle, ) = struct.unpack(
b'!B', self._buffer[base_offset + 3:base_offset + 4])
if index:
middle &= 0x0F
else:
middle = (0xF0 & middle) >> 4
offset = base_offset + index * 4
node_bytes = byte_from_int(middle) + self._buffer[offset:offset +
3]
elif record_size == 32:
offset = base_offset + index * 4
node_bytes = self._buffer[offset:offset + 4]
else:
raise InvalidDatabaseError('Unknown record size: {0}'.format(
record_size))
return struct.unpack(b'!I', node_bytes)[0]
def _resolve_data_pointer(self, pointer):
resolved = pointer - self._metadata.node_count + \
self._metadata.search_tree_size
if resolved > self._buffer_size:
raise InvalidDatabaseError(
"The MaxMind DB file's search tree is corrupt")
(data, _) = self._decoder.decode(resolved)
return data
def close(self):
"""Closes the MaxMind DB file and returns the resources to the system"""
# pylint: disable=unidiomatic-typecheck
if type(self._buffer) not in (str, bytes):
self._buffer.close()
self.closed = True
def __exit__(self, *args):
self.close()
def __enter__(self):
if self.closed:
raise ValueError('Attempt to reopen a closed MaxMind DB')
return self
class Metadata(object):
"""Metadata for the MaxMind DB reader"""
# pylint: disable=too-many-instance-attributes
def __init__(self, **kwargs):
"""Creates new Metadata object. kwargs are key/value pairs from spec"""
# Although I could just update __dict__, that is less obvious and it
# doesn't work well with static analysis tools and some IDEs
self.node_count = kwargs['node_count']
self.record_size = kwargs['record_size']
self.ip_version = kwargs['ip_version']
self.database_type = kwargs['database_type']
self.languages = kwargs['languages']
self.binary_format_major_version = kwargs[
'binary_format_major_version']
self.binary_format_minor_version = kwargs[
'binary_format_minor_version']
self.build_epoch = kwargs['build_epoch']
self.description = kwargs['description']
@property
def node_byte_size(self):
"""The size of a node in bytes"""
return self.record_size // 4
@property
def search_tree_size(self):
"""The size of the search tree"""
return self.node_count * self.node_byte_size
def __repr__(self):
args = ', '.join('%s=%r' % x for x in self.__dict__.items())
return '{module}.{class_name}({data})'.format(
module=self.__module__,
class_name=self.__class__.__name__,
data=args)
|