Support modifying the message, such as encryption.

[lhpqaq]

I made modifications to session.py to support obtaining and modifying the mutated version of the message before sending it. To encrypt the fields requiring encryption in the message, you can use the following method:

secret_key = None

def pre_send_callback(target, fuzz_data_logger, session, sock):
    mc = session.mutation_context

    # Method 1:
    # The mutated data packet to be sent
    original_data = session.fuzz_node.render(mc).hex()
    if secret_key:
        modified_data = original_data^secret_key
    session.modified_data = modified_data

    # Method 2:
    if list(mc.mutations.keys())[0] == "field requiring encryption"
        mc.mutations[list(mc.mutations.keys())[0]].value ^= secret_key

def post_test_case_callback(target, fuzz_data_logger, session, sock):
    if not secret_key:
        receive_data = session.last_recv.hex()
        secret_key = get_secret_key(receive_data)

session = Session(target=Target(SocketConnection(host, int(port))),receive_data_after_fuzz=True,,post_test_case_callbacks=[post_test_case_callback],pre_send_callbacks=[pre_send_callback])