2 * plugin.h: plugin handling
4 * Copyright (c) 2011 Cisco and/or its affiliates.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
18 #ifndef __included_plugin_h__
19 #define __included_plugin_h__
21 #include <vlib/vlib.h>
22 #include <vlib/unix/unix.h>
23 #include <sys/types.h>
30 * Almost anything which can be made to work in a vlib unix
31 * application will also work in a vlib plugin.
33 * The elf-section magic which registers static objects
34 * works so long as plugins are preset when the vlib unix process
35 * starts. But wait: there's more...
37 * If an application calls vlib_load_new_plugins() -- possibly after
38 * changing vlib_plugin_main.plugin_path / vlib_plugin_main.plugin_name_filter,
39 * -- new plugins will be loaded. That, in turn, allows considerable
40 * flexibility in terms of adding feature code or fixing bugs without
41 * requiring the data-plane process to restart.
43 * When the plugin mechanism loads a plugin, it uses dlsym to locate
44 * and call the plugin's function vlib_plugin_register() if it exists.
45 * A plugin which expects to be loaded after the vlib application
46 * starts uses this callback to modify the application. If vlib_plugin_register
47 * returns non-zero, the plugin mechanism dlclose()'s the plugin.
49 * Applications control the plugin search path and name filter by
50 * declaring the variables vlib_plugin_path and vlib_plugin_name_filter.
51 * libvlib_unix.la supplies weak references for these symbols which
52 * effectively disable the scheme. In order for the elf-section magic to
53 * work, static plugins must be loaded at the earliest possible moment.
55 * An application can change these parameters at any time and call
56 * vlib_load_new_plugins().
63 struct stat file_info;
68 /* loaded plugin info */
69 plugin_info_t *plugin_info;
70 uword *plugin_by_name_hash;
72 /* path and name filter */
74 u8 *plugin_name_filter;
76 /* handoff structure get callback */
77 void *handoff_structure_get_cb;
80 vlib_main_t *vlib_main;
83 plugin_main_t vlib_plugin_main;
85 int vlib_plugin_early_init (vlib_main_t *vm);
86 int vlib_load_new_plugins (plugin_main_t *pm, int from_early_init);
88 #endif /* __included_plugin_h__ */