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handingkang-ohmybs/figcode/awdb/reader.py
2024-05-27 10:39:10 +08:00

209 lines
7.0 KiB
Python

from __future__ import unicode_literals
try:
import mmap
except ImportError:
mmap = None
import struct
from awdb.compat import compat_ip_address, string_type
from awdb.const import MODE_AUTO, MODE_MMAP, MODE_FILE, MODE_MEMORY, MODE_FD
from awdb.decoder import Decoder
from awdb.errors import InvalidDatabaseError
from awdb.file import FileBuffer
class Reader(object):
_DATA_SECTION_SEPARATOR_SIZE = 16
_METADATA_START_MARKER = b"\xAB\xCD\xEFipplus360.com"
_ipv4_start = None
def __init__(self, database, mode=MODE_AUTO):
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()
filename = database
elif mode in (MODE_AUTO, MODE_FILE):
self._buffer = FileBuffer(database)
self._buffer_size = self._buffer.size()
filename = database
elif mode == MODE_MEMORY:
with open(database, 'rb') as db_file:
self._buffer = db_file.read()
self._buffer_size = len(self._buffer)
filename = database
elif mode == MODE_FD:
self._buffer = database.read()
self._buffer_size = len(self._buffer)
filename = database.name
else:
raise ValueError(
'Unsupported open mode ({0}). Only MODE_AUTO, MODE_FILE, '
'MODE_MEMORY and MODE_FD are supported 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 AW DB file?'
''.format(filename))
metadata_start += len(self._METADATA_START_MARKER)
metadata_decoder = Decoder(self._buffer, metadata_start)
(metadata, _) = metadata_decoder.decode(metadata_start)
self._metadata = Metadata(**metadata)
self._decoder = Decoder(
self._buffer, self._metadata.search_tree_size +
self._DATA_SECTION_SEPARATOR_SIZE)
self.closed = False
def metadata(self):
return self._metadata
def get(self, ip_address):
(record, _) = self.get_with_prefix_len(ip_address)
return record
def get_with_prefix_len(self, ip_address):
if isinstance(ip_address, string_type):
address = compat_ip_address(ip_address)
else:
address = ip_address
try:
packed_address = bytearray(address.packed)
except AttributeError:
raise TypeError('argument 1 must be a string or ipaddress object')
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, prefix_len) = self._find_address_in_tree(packed_address)
if pointer:
return self._resolve_data_pointer(pointer), prefix_len
return None, prefix_len
def _find_address_in_tree(self, packed):
bit_count = len(packed) * 8
node = self._start_node(bit_count)
node_count = self._metadata.node_count
i = 0
while i < bit_count and node < node_count:
bit = 1 & (packed[i >> 3] >> 7 - (i % 8))
node = self._read_node(node, bit)
i = i + 1
if node == node_count:
return 0, i
if node > node_count:
return node, i
raise InvalidDatabaseError('Invalid node in search tree')
def _start_node(self, length):
if self._metadata.ip_version != 6 or length == 128:
return 0
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:
offset = base_offset + 3 * index
node_bytes = bytearray(self._buffer[offset:offset + 4])
if index:
node_bytes[0] = 0x0F & node_bytes[0]
else:
middle = (0xF0 & node_bytes.pop()) >> 4
node_bytes.insert(0, middle)
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 AW DB file's search tree is corrupt")
(data, _) = self._decoder.decode(resolved)
return data
def close(self):
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 AW DB')
return self
class Metadata(object):
def __init__(self, **kwargs):
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):
return self.record_size // 4
@property
def search_tree_size(self):
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)