tls_client_hello: Python parsing library

KS implementation details

License: MIT

References

This page hosts a formal specification of tls_client_hello using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Usage

Runtime library

All parsing code for Python generated by Kaitai Struct depends on the Python runtime library. You have to install it before you can parse data.

The Python runtime library can be installed from PyPI:

python3 -m pip install kaitaistruct

Code

Parse a local file and get structure in memory:

data = TlsClientHello.from_file("path/to/local/file.bin")

Or parse structure from a bytes:

from kaitaistruct import KaitaiStream, BytesIO

raw = b"\x00\x01\x02..."
data = TlsClientHello(KaitaiStream(BytesIO(raw)))

After that, one can get various attributes from the structure by invoking getter methods like:

data.version # => get version

Python source code to parse tls_client_hello

tls_client_hello.py

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild
# type: ignore

import kaitaistruct
from kaitaistruct import KaitaiStruct, KaitaiStream, BytesIO


if getattr(kaitaistruct, 'API_VERSION', (0, 9)) < (0, 11):
    raise Exception("Incompatible Kaitai Struct Python API: 0.11 or later is required, but you have %s" % (kaitaistruct.__version__))

class TlsClientHello(KaitaiStruct):
    def __init__(self, _io, _parent=None, _root=None):
        super(TlsClientHello, self).__init__(_io)
        self._parent = _parent
        self._root = _root or self
        self._read()

    def _read(self):
        self.version = TlsClientHello.Version(self._io, self, self._root)
        self.random = TlsClientHello.Random(self._io, self, self._root)
        self.session_id = TlsClientHello.SessionId(self._io, self, self._root)
        self.cipher_suites = TlsClientHello.CipherSuites(self._io, self, self._root)
        self.compression_methods = TlsClientHello.CompressionMethods(self._io, self, self._root)
        if self._io.is_eof() == False:
            pass
            self.extensions = TlsClientHello.Extensions(self._io, self, self._root)



    def _fetch_instances(self):
        pass
        self.version._fetch_instances()
        self.random._fetch_instances()
        self.session_id._fetch_instances()
        self.cipher_suites._fetch_instances()
        self.compression_methods._fetch_instances()
        if self._io.is_eof() == False:
            pass
            self.extensions._fetch_instances()


    class Alpn(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.Alpn, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.ext_len = self._io.read_u2be()
            self.alpn_protocols = []
            i = 0
            while not self._io.is_eof():
                self.alpn_protocols.append(TlsClientHello.Protocol(self._io, self, self._root))
                i += 1



        def _fetch_instances(self):
            pass
            for i in range(len(self.alpn_protocols)):
                pass
                self.alpn_protocols[i]._fetch_instances()



    class CipherSuites(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.CipherSuites, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.len = self._io.read_u2be()
            self.cipher_suites = []
            for i in range(self.len // 2):
                self.cipher_suites.append(self._io.read_u2be())



        def _fetch_instances(self):
            pass
            for i in range(len(self.cipher_suites)):
                pass



    class CompressionMethods(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.CompressionMethods, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.len = self._io.read_u1()
            self.compression_methods = self._io.read_bytes(self.len)


        def _fetch_instances(self):
            pass


    class Extension(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.Extension, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.type = self._io.read_u2be()
            self.len = self._io.read_u2be()
            _on = self.type
            if _on == 0:
                pass
                self._raw_body = self._io.read_bytes(self.len)
                _io__raw_body = KaitaiStream(BytesIO(self._raw_body))
                self.body = TlsClientHello.Sni(_io__raw_body, self, self._root)
            elif _on == 16:
                pass
                self._raw_body = self._io.read_bytes(self.len)
                _io__raw_body = KaitaiStream(BytesIO(self._raw_body))
                self.body = TlsClientHello.Alpn(_io__raw_body, self, self._root)
            else:
                pass
                self.body = self._io.read_bytes(self.len)


        def _fetch_instances(self):
            pass
            _on = self.type
            if _on == 0:
                pass
                self.body._fetch_instances()
            elif _on == 16:
                pass
                self.body._fetch_instances()
            else:
                pass


    class Extensions(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.Extensions, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.len = self._io.read_u2be()
            self.extensions = []
            i = 0
            while not self._io.is_eof():
                self.extensions.append(TlsClientHello.Extension(self._io, self, self._root))
                i += 1



        def _fetch_instances(self):
            pass
            for i in range(len(self.extensions)):
                pass
                self.extensions[i]._fetch_instances()



    class Protocol(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.Protocol, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.strlen = self._io.read_u1()
            self.name = self._io.read_bytes(self.strlen)


        def _fetch_instances(self):
            pass


    class Random(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.Random, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.gmt_unix_time = self._io.read_u4be()
            self.random = self._io.read_bytes(28)


        def _fetch_instances(self):
            pass


    class ServerName(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.ServerName, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.name_type = self._io.read_u1()
            self.length = self._io.read_u2be()
            self.host_name = self._io.read_bytes(self.length)


        def _fetch_instances(self):
            pass


    class SessionId(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.SessionId, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.len = self._io.read_u1()
            self.sid = self._io.read_bytes(self.len)


        def _fetch_instances(self):
            pass


    class Sni(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.Sni, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.list_length = self._io.read_u2be()
            self.server_names = []
            i = 0
            while not self._io.is_eof():
                self.server_names.append(TlsClientHello.ServerName(self._io, self, self._root))
                i += 1



        def _fetch_instances(self):
            pass
            for i in range(len(self.server_names)):
                pass
                self.server_names[i]._fetch_instances()



    class Version(KaitaiStruct):
        def __init__(self, _io, _parent=None, _root=None):
            super(TlsClientHello.Version, self).__init__(_io)
            self._parent = _parent
            self._root = _root
            self._read()

        def _read(self):
            self.major = self._io.read_u1()
            self.minor = self._io.read_u1()


        def _fetch_instances(self):
            pass