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Vector Packet Processing
plugin.h
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1 /*
2  * plugin.h: plugin handling
3  *
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:
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
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.
16  */
17 
18 #ifndef __included_plugin_h__
19 #define __included_plugin_h__
20 
21 #include <vlib/vlib.h>
22 #include <vlib/unix/unix.h>
23 #include <sys/types.h>
24 #include <sys/stat.h>
25 #include <unistd.h>
26 
27 /*
28  * vlib plugin scheme
29  *
30  * Almost anything which can be made to work in a vlib unix
31  * application will also work in a vlib plugin.
32  *
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...
36  *
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.
42  *
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.
48  *
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.
54  *
55  * An application can change these parameters at any time and call
56  * vlib_load_new_plugins().
57  */
58 
59 
60 
61 typedef struct
62 {
63  u8 *name;
64  struct stat file_info;
65  void *handle;
67 
68 typedef struct
69 {
70  /* loaded plugin info */
73 
74  /* path and name filter */
77 
78  /* handoff structure get callback */
80 
81  /* usual */
84 
86 
88 int vlib_load_new_plugins (plugin_main_t * pm, int from_early_init);
89 
90 #endif /* __included_plugin_h__ */
91 
92 /*
93  * fd.io coding-style-patch-verification: ON
94  *
95  * Local Variables:
96  * eval: (c-set-style "gnu")
97  * End:
98  */
plugin_main_t vlib_plugin_main
Definition: plugin.c:22
vlib_main_t * vlib_main
Definition: plugin.h:82
int vlib_plugin_early_init(vlib_main_t *vm)
Definition: plugin.c:207
u8 * name
Definition: plugin.h:63
u8 * plugin_path
Definition: plugin.h:75
uword * plugin_by_name_hash
Definition: plugin.h:72
void * handoff_structure_get_cb
Definition: plugin.h:79
int vlib_load_new_plugins(plugin_main_t *pm, int from_early_init)
Definition: plugin.c:125
u64 uword
Definition: types.h:112
plugin_info_t * plugin_info
Definition: plugin.h:71
u8 * plugin_name_filter
Definition: plugin.h:76
unsigned char u8
Definition: types.h:56
void * handle
Definition: plugin.h:65