import hashlib import os.path import ID2TLib.libpcapreader as pr import ID2TLib.Utility as Util class PcapFile(object): def __init__(self, pcap_file_path: str): """ Creates a new PcapFile associated to the PCAP file at pcap_file_path. :param pcap_file_path: The path to the PCAP file """ self.pcap_file_path = pcap_file_path def merge_attack(self, attack_pcap_path: str): """ Merges the loaded PCAP with the PCAP at attack_pcap_path. :param attack_pcap_path: The path to the PCAP file to merge with the PCAP at pcap_file_path :return: The file path of the resulting PCAP file """ pcap = pr.pcap_processor(self.pcap_file_path, "False", Util.RESOURCE_DIR) file_out_path = pcap.merge_pcaps(attack_pcap_path) return file_out_path def get_file_hash(self): """ Returns the hash for the loaded PCAP file. The hash is calculated based on: - the file size in bytes - the first 224*40000 bytes of the file :return: The hash for the PCAP file as string. """ # Blocksize in bytes const_blocksize = 224 # Number of blocks to read at beginning of file const_max_blocks_read = 40000 # Initialize required variables hasher = hashlib.sha224() blocks_read = 0 # Hash calculation with open(self.pcap_file_path, 'rb') as afile: # Add filename -> makes trouble when renaming the PCAP # hasher.update(afile.name.encode('utf-8')) # Add file's last modification date -> makes trouble when copying the PCAP # hasher.update(str(time.ctime(os.path.getmtime(self.pcap_file_path))).encode('utf-8')) # Add file size hasher.update(str(os.path.getsize(self.pcap_file_path)).encode('utf-8')) # Add max. first 40000 * 224 bytes = 8,5 MB of file buf = afile.read(const_blocksize) blocks_read += 1 while len(buf) > 0 and blocks_read < const_max_blocks_read: hasher.update(buf) buf = afile.read(const_blocksize) blocks_read += 1 return hasher.hexdigest() def get_db_path(self, root_directory: str = os.path.join(Util.CACHE_DIR, 'db')): """ Creates a path based on a hashed directory structure. Derives a hash code by the file's hash and derives thereof the database path. Code and idea based on: http://michaelandrews.typepad.com/the_technical_times/2009/10/creating-a-hashed-directory-structure.html :param root_directory: The root directory of the hashed directory structure (optional) :return: The full path to the database file """ def hashcode(string_in: str): """ Creates a hashcode of a string, based on Java's hashcode implementation. Code based on: http://garage.pimentech.net/libcommonPython_src_python_libcommon_javastringhashcode/ :param string_in: The string the hashcode should be calculated from :return: The hashcode as string """ h = 0 for c in string_in: h = (31 * h + ord(c)) & 0xFFFFFFFF return ((h + 0x80000000) & 0xFFFFFFFF) - 0x80000000 file_hash = self.get_file_hash() hashcode = hashcode(file_hash) mask = 255 dir_first_level = hashcode & mask dir_second_level = (hashcode >> 8) & mask return os.path.join(root_directory, str(dir_first_level), str(dir_second_level), file_hash[0:12] + ".sqlite3")