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/* Scripting foo
* Copyright (C) 2020 NVIDIA Corporation
* Quentin Young
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; see the file COPYING; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __FRRSCRIPT_H__
#define __FRRSCRIPT_H__
#include <zebra.h>
#ifdef HAVE_SCRIPTING
#include <lua.h>
#include "frrlua.h"
#include "../bgpd/bgp_script.h"
#ifdef __cplusplus
extern "C" {
#endif
typedef void (*encoder_func)(lua_State *, const void *);
typedef void *(*decoder_func)(lua_State *, int);
struct frrscript_codec {
const char *typename;
encoder_func encoder;
decoder_func decoder;
};
struct lua_function_state {
const char *name;
lua_State *L;
};
struct frrscript {
/* Script name */
char *name;
/* Hash of Lua function name to Lua function state */
struct hash *lua_function_hash;
};
/*
* Hash related functions for lua_function_hash
*/
void *lua_function_alloc(void *arg);
unsigned int lua_function_hash_key(const void *data);
bool lua_function_hash_cmp(const void *d1, const void *d2);
struct frrscript_env {
/* Value type */
const char *typename;
/* Binding name */
const char *name;
/* Value */
const void *val;
};
/*
* Create new FRR script.
*/
struct frrscript *frrscript_new(const char *name);
/*
* Load a function into frrscript, run callback if any
*/
int frrscript_load(struct frrscript *fs, const char *function_name,
int (*load_cb)(struct frrscript *));
/*
* Destroy FRR script.
*/
void frrscript_unload(struct frrscript *fs);
/*
* Register a Lua codec for a type.
*
* tname
* Name of type; e.g., "peer", "ospf_interface", etc. Chosen at will.
*
* codec(s)
* Function pointer to codec struct. Encoder function should push a Lua
* table representing the passed argument - which will have the C type
* associated with the chosen 'tname' to the provided stack. The decoder
* function should pop a value from the top of the stack and return a heap
* chunk containing that value. Allocations should be made with MTYPE_TMP.
*
* If using the plural function variant, pass a NULL-terminated array.
*
*/
void frrscript_register_type_codec(struct frrscript_codec *codec);
void frrscript_register_type_codecs(struct frrscript_codec *codecs);
/*
* Initialize scripting subsystem. Call this before anything else.
*
* scriptdir
* Directory in which to look for scripts
*/
void frrscript_init(const char *scriptdir);
#define ENCODE_ARGS(name, value) ENCODE_ARGS_WITH_STATE(lfs->L, value)
#define DECODE_ARGS(name, value) \
do { \
lua_getfield(lfs->L, 1, name); \
if (lua_isnil(lfs->L, 2)) { \
lua_pop(lfs->L, 1); \
} else { \
DECODE_ARGS_WITH_STATE(lfs->L, value); \
} \
assert(lua_gettop(lfs->L) == 1); \
} while (0)
/*
* Maps the type of value to its encoder/decoder.
* Add new mappings here.
*
* L
* Lua state
* scriptdir
* Directory in which to look for scripts
*/
#define ENCODE_ARGS_WITH_STATE(L, value) \
_Generic((value), \
long long * : lua_pushintegerp, \
struct prefix * : lua_pushprefix, \
struct interface * : lua_pushinterface, \
struct in_addr * : lua_pushinaddr, \
struct in6_addr * : lua_pushin6addr, \
union sockunion * : lua_pushsockunion, \
time_t * : lua_pushtimet, \
char * : lua_pushstring_wrapper, \
struct attr * : lua_pushattr, \
struct peer * : lua_pushpeer, \
const struct prefix * : lua_pushprefix \
)(L, value)
#define DECODE_ARGS_WITH_STATE(L, value) \
_Generic((value), \
long long * : lua_decode_integerp, \
struct prefix * : lua_decode_prefix, \
struct interface * : lua_decode_interface, \
struct in_addr * : lua_decode_inaddr, \
struct in6_addr * : lua_decode_in6addr, \
union sockunion * : lua_decode_sockunion, \
time_t * : lua_decode_timet, \
char * : lua_decode_stringp, \
struct attr * : lua_decode_attr, \
struct peer * : lua_decode_noop, \
const struct prefix * : lua_decode_noop \
)(L, -1, value)
/*
* Call script.
*
* fs
* The script to call; this is obtained from frrscript_load().
*
* Returns:
* 0 if the script ran successfully, nonzero otherwise.
*/
int _frrscript_call_lua(struct lua_function_state *lfs, int nargs);
/*
* Wrapper for call script. Maps values passed in to their encoder
* and decoder types.
*
* fs
* The script to call; this is obtained from frrscript_load().
*
* Returns:
* 0 if the script ran successfully, nonzero otherwise.
*/
#define frrscript_call(fs, f, ...) \
({ \
struct lua_function_state lookup = {.name = f}; \
struct lua_function_state *lfs; \
lfs = hash_lookup(fs->lua_function_hash, &lookup); \
lfs == NULL ? ({ \
zlog_err( \
"frrscript: '%s.lua': '%s': tried to call this function but it was not loaded", \
fs->name, f); \
1; \
}) \
: ({ \
MAP_LISTS(ENCODE_ARGS, ##__VA_ARGS__); \
_frrscript_call_lua(lfs, PP_NARG(__VA_ARGS__)); \
}) != 0 \
? ({ \
zlog_err( \
"frrscript: '%s.lua': '%s': this function called but returned non-zero exit code. No variables modified.", \
fs->name, f); \
1; \
}) \
: ({ \
MAP_LISTS(DECODE_ARGS, ##__VA_ARGS__); \
0; \
}); \
})
/*
* Get result from finished script.
*
* fs
* The script. This script must have been run already.
*
* result
* The result to extract from the script.
* This reuses the frrscript_env type, but only the typename and name fields
* need to be set. The value is returned directly.
*
* Returns:
* The script result of the specified name and type, or NULL.
*/
void *frrscript_get_result(struct frrscript *fs, const char *function_name,
const char *name,
void *(*lua_to)(lua_State *L, int idx));
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* HAVE_SCRIPTING */
#endif /* __FRRSCRIPT_H__ */
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