# Source code for M2Crypto.SSL.cb

    """SSL callbacks

    Copyright (c) 1999-2003 Ng Pheng Siong. All rights reserved."""

    import sys

    from M2Crypto import X509, m2, types as C
    from typing import List

    __all__ = [
        "unknown_issuer",
        "ssl_verify_callback_stub",
        "ssl_verify_callback",
        "ssl_verify_callback_allow_unknown_ca",
        "ssl_info_callback",
    ]

    def ssl_verify_callback_stub(ssl_ctx_ptr, x509_ptr, errnum, errdepth, ok):
        # Deprecated
        return ok

    unknown_issuer: List[int] = [
        m2.X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT,
        m2.X509_V_ERR_UNABLE_TO_GET_ISSUER_CERT_LOCALLY,
        m2.X509_V_ERR_UNABLE_TO_VERIFY_LEAF_SIGNATURE,
        m2.X509_V_ERR_CERT_UNTRUSTED,
    ]

    def ssl_verify_callback(
        ssl_ctx_ptr: C.SSL_CTX,
        x509_ptr: C.X509,
        errnum: int,
        errdepth: int,
        ok: int,
    ) -> int:
        from M2Crypto.SSL.Context import Context, ctxmap

        ssl_ctx = ctxmap()[id(ssl_ctx_ptr)]
        if errnum in unknown_issuer:
            if ssl_ctx.get_allow_unknown_ca():
                sys.stderr.write(
                    "policy: %s: permitted...\n" % (m2.x509_get_verify_error(errnum))
                )
                sys.stderr.flush()
                ok = 1
        # CRL checking goes here...
        if ok:
            if ssl_ctx.get_verify_depth() >= errdepth:
                ok = 1
            else:
                ok = 0
        return ok

    def ssl_verify_callback_allow_unknown_ca(
        ok: int, store: X509.X509_Store_Context
    ) -> int:
        """
        Callback that allows unknown CA errors.
        This version relies on a corrected SWIG typemap to receive a valid 'store' object.
        """
        store_ptr = store.ctx
        errnum = m2.x509_store_ctx_get_error(store_ptr)

        if errnum in unknown_issuer:
            # It's an error we want to ignore. Clear the error from the
            # context and return 1 to override the failure.
            m2.x509_store_ctx_set_error(store_ptr, m2.X509_V_OK)
            return 1

        # For any other error, respect the original verification status.
        return ok

    # Cribbed from OpenSSL's apps/s_cb.c.

    def ssl_info_callback(where: int, ret: int, ssl_ptr: C.SSL) -> None:
        where_int = where & ~m2.SSL_ST_MASK
        if where_int & m2.SSL_ST_CONNECT:
            state = "SSL connect"
        elif where_int & m2.SSL_ST_ACCEPT:
            state = "SSL accept"
        else:
            state = "SSL state unknown"

        if where & m2.SSL_CB_LOOP:
            sys.stderr.write("LOOP: %s: %s\n" % (state, m2.ssl_get_state_v(ssl_ptr)))
            sys.stderr.flush()
            return

        if where & m2.SSL_CB_EXIT:
            if not ret:
                sys.stderr.write("FAILED: %s: %s\n" % (state, m2.ssl_get_state_v(ssl_ptr)))
                sys.stderr.flush()
            else:
                sys.stderr.write("INFO: %s: %s\n" % (state, m2.ssl_get_state_v(ssl_ptr)))
                sys.stderr.flush()
            return

        if where & m2.SSL_CB_ALERT:
            # Use a new variable for the alert operation string
            alert_op = "read" if (where & m2.SSL_CB_READ) else "write"
            sys.stderr.write(
                "ALERT: %s: %s: %s\n"
                % (
                    alert_op,
                    m2.ssl_get_alert_type_v(ret),
                    m2.ssl_get_alert_desc_v(ret),
                )
            )
            sys.stderr.flush()
            return