* This is a hook to be registered with the client connection pool that should

 * ensure the backend connection is closed as soon as the client connection is

 * closed. As NTLM appears to authenticate TCP connections instead of HTTP

 * requests (which is broken by design), we want to really close the backend

 * connection and not let other clients re-use it. Otherwise the other clients

 * may get authenticated with foreign auth credentials they don't own.

 */

typedef struct {

    const char *proxy_function;

    proxy_conn_rec *backend;

    server_rec *server;

} http_backend_cleanup_t;

static apr_status_t proxy_http_ntlm_disconnect_backend(void *data) {

    http_backend_cleanup_t *d = (http_backend_cleanup_t *)data;

    d->backend->close = 1;

    ap_proxy_release_connection(d->proxy_function, d->backend, d->server);

    return APR_SUCCESS;

};

/*

    const char *auth_hdr;

    int is_ntlm_request = 0;

    http_backend_cleanup_t *cleanup_data;

    /* check whether we need to re-use an already established backend connection */

    backend = (proxy_conn_rec *)ap_get_module_config(c->conn_config, &proxy_http_module);

    if (backend) {

        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,

                     "proxy: re-using already established connection to backend server");

    } else {

        /*

         * check whether we have an NTLM request that requires

         * client connections mapping to exactly one backend connection

         * and no shared usage of backend connections by multiple clients.

         */

        auth_hdr = apr_table_get(r->headers_in, "WWW-Authenticate");

        if (auth_hdr && (!strcasecmp(auth_hdr, "NTLM") ||

                         !strncasecmp(auth_hdr, "NTLM ", 5))) {

            is_ntlm_request = 1;

            /* enforce that this backend connection is not shared with other

             * clients. */

            backend->close = 1;

            /* Register backend connection with client connection. */

            cleanup_data = apr_pcalloc(c->pool, sizeof(cleanup_data));

            cleanup_data->proxy_function = proxy_function;

            cleanup_data->backend = backend;

            cleanup_data->server = r->server;

            apr_pool_cleanup_register(c->pool, cleanup_data,

                                      proxy_http_ntlm_disconnect_backend,

                                      apr_pool_cleanup_null);

            ap_set_module_config(c->conn_config, &proxy_http_module, backend);

        }

    }

        if (is_ntlm_request) {

            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,

                         "proxy: keeping backend connection open until client disconnects");

            return status;

        }