lib/frrscript.h

   1 /* Scripting foo
   2  * Copyright (C) 2020  NVIDIA Corporation
   3  * Quentin Young
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the Free
   7  * Software Foundation; either version 2 of the License, or (at your option)
   8  * any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; see the file COPYING; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  18  */
  19 #ifndef __FRRSCRIPT_H__
  20 #define __FRRSCRIPT_H__
  21
  22 #include <zebra.h>
  23
  24 #ifdef HAVE_SCRIPTING
  25
  26 #include <lua.h>
  27 #include "frrlua.h"
  28 #include "../bgpd/bgp_script.h"
  29
  30 #ifdef __cplusplus
  31 extern "C" {
  32 #endif
  33
  34 typedef void (*encoder_func)(lua_State *, const void *);
  35 typedef void *(*decoder_func)(lua_State *, int);
  36
  37 struct frrscript_codec {
  38         const char *typename;
  39         encoder_func encoder;
  40         decoder_func decoder;
  41 };
  42
  43 struct frrscript {
  44         /* Script name */
  45         char *name;
  46
  47         /* Lua state */
  48         struct lua_State *L;
  49 };
  50
  51 struct frrscript_env {
  52         /* Value type */
  53         const char *typename;
  54
  55         /* Binding name */
  56         const char *name;
  57
  58         /* Value */
  59         const void *val;
  60 };
  61
  62 /*
  63  * Create new FRR script.
  64  */
  65 struct frrscript *frrscript_load(const char *name,
  66                                  int (*load_cb)(struct frrscript *));
  67
  68 /*
  69  * Destroy FRR script.
  70  */
  71 void frrscript_unload(struct frrscript *fs);
  72
  73 /*
  74  * Register a Lua codec for a type.
  75  *
  76  * tname
  77  *    Name of type; e.g., "peer", "ospf_interface", etc. Chosen at will.
  78  *
  79  * codec(s)
  80  *    Function pointer to codec struct. Encoder function should push a Lua
  81  *    table representing the passed argument - which will have the C type
  82  *    associated with the chosen 'tname' to the provided stack. The decoder
  83  *    function should pop a value from the top of the stack and return a heap
  84  *    chunk containing that value. Allocations should be made with MTYPE_TMP.
  85  *
  86  *    If using the plural function variant, pass a NULL-terminated array.
  87  *
  88  */
  89 void frrscript_register_type_codec(struct frrscript_codec *codec);
  90 void frrscript_register_type_codecs(struct frrscript_codec *codecs);
  91
  92 /*
  93  * Initialize scripting subsystem. Call this before anything else.
  94  *
  95  * scriptdir
  96  *    Directory in which to look for scripts
  97  */
  98 void frrscript_init(const char *scriptdir);
  99
 100 #define ENCODE_ARGS(name, value)                                               \
 101         do {                                                                   \
 102                 ENCODE_ARGS_WITH_STATE(L, value);                              \
 103                 lua_setglobal(L, name);                                        \
 104         } while (0)
 105
 106 #define DECODE_ARGS(name, value)                                               \
 107         do {                                                                   \
 108                 lua_getglobal(L, name);                                        \
 109                 DECODE_ARGS_WITH_STATE(L, value);                              \
 110         } while (0)
 111
 112 /*
 113  * Maps the type of value to its encoder/decoder.
 114  * Add new mappings here.
 115  *
 116  * L
 117  *    Lua state
 118  * scriptdir
 119  *    Directory in which to look for scripts
 120  */
 121 #define ENCODE_ARGS_WITH_STATE(L, value)                                       \
 122         _Generic((value), \
 123 long long * : lua_pushintegerp,                                 \
 124 struct prefix * : lua_pushprefix,                               \
 125 struct interface * : lua_pushinterface,                         \
 126 struct in_addr * : lua_pushinaddr,                              \
 127 struct in6_addr * : lua_pushin6addr,                            \
 128 union sockunion * : lua_pushsockunion,                          \
 129 time_t * : lua_pushtimet,                                       \
 130 char * : lua_pushstring_wrapper,                                \
 131 struct attr * : lua_pushattr,                                   \
 132 struct peer * : lua_pushpeer,                                   \
 133 const struct prefix * : lua_pushprefix                          \
 134 )(L, value)
 135
 136 #define DECODE_ARGS_WITH_STATE(L, value)                                       \
 137         _Generic((value), \
 138 long long * : lua_decode_integerp,                              \
 139 struct prefix * : lua_decode_prefix,                            \
 140 struct interface * : lua_decode_interface,                      \
 141 struct in_addr * : lua_decode_inaddr,                           \
 142 struct in6_addr * : lua_decode_in6addr,                         \
 143 union sockunion * : lua_decode_sockunion,                       \
 144 time_t * : lua_decode_timet,                                    \
 145 char * : lua_decode_stringp,                                    \
 146 struct attr * : lua_decode_attr,                                \
 147 struct peer * : lua_decode_noop,                                \
 148 const struct prefix * : lua_decode_noop                         \
 149 )(L, -1, value)
 150
 151 /*
 152  * Call script.
 153  *
 154  * fs
 155  *    The script to call; this is obtained from frrscript_load().
 156  *
 157  * Returns:
 158  *    0 if the script ran successfully, nonzero otherwise.
 159  */
 160 int _frrscript_call(struct frrscript *fs);
 161
 162 /*
 163  * Wrapper for call script. Maps values passed in to their encoder
 164  * and decoder types.
 165  *
 166  * fs
 167  *    The script to call; this is obtained from frrscript_load().
 168  *
 169  * Returns:
 170  *    0 if the script ran successfully, nonzero otherwise.
 171  */
 172 #define frrscript_call(fs, ...)                                                \
 173         ({                                                                     \
 174                 lua_State *L = fs->L;                                          \
 175                 MAP_LISTS(ENCODE_ARGS, ##__VA_ARGS__);                         \
 176                 int ret = _frrscript_call(fs);                                 \
 177                 if (ret == 0) {                                                \
 178                         MAP_LISTS(DECODE_ARGS, ##__VA_ARGS__);                 \
 179                 }                                                              \
 180                 ret;                                                           \
 181         })
 182
 183 /*
 184  * Get result from finished script.
 185  *
 186  * fs
 187  *    The script. This script must have been run already.
 188  *
 189  * result
 190  *    The result to extract from the script.
 191  *    This reuses the frrscript_env type, but only the typename and name fields
 192  *    need to be set. The value is returned directly.
 193  *
 194  * Returns:
 195  *    The script result of the specified name and type, or NULL.
 196  */
 197 void *frrscript_get_result(struct frrscript *fs,
 198                            const struct frrscript_env *result);
 199
 200 #ifdef __cplusplus
 201 }
 202 #endif /* __cplusplus */
 203
 204 #endif /* HAVE_SCRIPTING */
 205
 206 #endif /* __FRRSCRIPT_H__ */