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.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().
60 typedef CLIB_PACKED(struct {
62 const char version[32];
63 const char version_required[32];
64 const char overrides[256];
65 const char *early_init;
66 const char *description;
67 }) vlib_plugin_registration_t;
74 struct stat file_info;
77 /* plugin registration */
78 vlib_plugin_registration_t *reg;
87 u8 skip_version_check;
92 /* loaded plugin info */
93 plugin_info_t *plugin_info;
94 uword *plugin_by_name_hash;
95 uword *plugin_overrides_by_name_hash;
97 /* paths and name filters */
99 u8 *plugin_name_filter;
101 u8 *vat_plugin_name_filter;
102 u8 plugins_default_disable;
104 /* plugin configs and hash by name */
105 plugin_config_t *configs;
106 uword *config_index_by_name;
108 /* Plugin log, avoid filling syslog w/ junk */
109 vlib_log_class_t logger;
112 vlib_main_t *vlib_main;
115 extern plugin_main_t vlib_plugin_main;
117 clib_error_t *vlib_plugin_config (vlib_main_t * vm, unformat_input_t * input);
118 int vlib_plugin_early_init (vlib_main_t * vm);
119 int vlib_load_new_plugins (plugin_main_t * pm, int from_early_init);
120 void *vlib_get_plugin_symbol (char *plugin_name, char *symbol_name);
121 u8 *vlib_get_vat_plugin_path (void);
123 #define VLIB_PLUGIN_REGISTER() \
124 vlib_plugin_registration_t vlib_plugin_registration \
125 __attribute__((__section__(".vlib_plugin_registration")))
127 /* Call a plugin init function: used for init function dependencies. */
128 #define vlib_call_plugin_init_function(vm,p,x) \
130 clib_error_t *(*_f)(vlib_main_t *); \
132 clib_error_t * _error = 0; \
133 _fptr= vlib_get_plugin_symbol \
134 (p, CLIB_STRING_MACRO(_vlib_init_function_##x)); \
137 _error = clib_error_return \
138 (0, "Plugin %s and/or symbol %s not found.", \
139 p, CLIB_STRING_MACRO(_vlib_init_function_##x)); \
143 _f = (void *)(_fptr[0]); \
145 if (_fptr && ! hash_get (vm->init_functions_called, _f)) \
147 hash_set1 (vm->init_functions_called, _f); \
153 #endif /* __included_plugin_h__ */
156 * fd.io coding-style-patch-verification: ON
159 * eval: (c-set-style "gnu")