utils.py 文件源码

def __init__(self, filename, fdesc, magic):
        self.filename = filename
        self.f = fdesc
        # A list of (linktype, snaplen); will be populated by IDBs.
        self.interfaces = []
        self.blocktypes = {
            1: self.read_block_idb,
            6: self.read_block_epb,
        }
        if magic != "\x0a\x0d\x0d\x0a": # PcapNg:
            raise Scapy_Exception(
                "Not a pcapng capture file (bad magic: %r)" % magic
            )
        # see https://github.com/pcapng/pcapng
        blocklen, magic = self.f.read(4), self.f.read(4)
        if magic == "\x1a\x2b\x3c\x4d":
            self.endian = ">"
        elif magic == "\x4d\x3c\x2b\x1a":
            self.endian = "<"
        else:
            raise Scapy_Exception("Not a pcapng capture file (bad magic)")
        self.f.seek(0)