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// SPDX-License-Identifier: GPL-2.0-or-later
/* Scripting foo
* Copyright (C) 2020 NVIDIA Corporation
* Quentin Young
*/
#ifndef __FRRSCRIPT_H__
#define __FRRSCRIPT_H__
#include <zebra.h>
#ifdef HAVE_SCRIPTING
#include <lua.h>
#include <nexthop.h>
#include <nexthop_group.h>
#include "frrlua.h"
#include "bgpd/bgp_script.h" // for peer and attr encoders/decoders
#ifdef __cplusplus
extern "C" {
#endif
/* Forward declarations */
struct zebra_dplane_ctx;
extern void lua_pushzebra_dplane_ctx(lua_State *L,
const struct zebra_dplane_ctx *ctx);
extern void lua_decode_zebra_dplane_ctx(lua_State *L, int idx,
struct zebra_dplane_ctx *ctx);
/*
* Script name hash
*/
PREDECL_HASH(frrscript_names);
struct frrscript_names_entry {
/* Name of a Lua hook call */
char function_name[MAXPATHLEN];
/* Lua script in which to look for it */
char script_name[MAXPATHLEN];
struct frrscript_names_item item;
};
extern struct frrscript_names_head frrscript_names_hash;
int frrscript_names_hash_cmp(const struct frrscript_names_entry *snhe1,
const struct frrscript_names_entry *snhe2);
uint32_t frrscript_names_hash_key(const struct frrscript_names_entry *snhe);
DECLARE_HASH(frrscript_names, struct frrscript_names_entry, item,
frrscript_names_hash_cmp, frrscript_names_hash_key);
int frrscript_names_add_function_name(const char *function_name);
void frrscript_names_destroy(void);
int frrscript_names_set_script_name(const char *function_name,
const char *script_name);
char *frrscript_names_get_script_name(const char *function_name);
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 struct frrscript for a Lua script.
* This will hold the states for the Lua functions in this script.
*
* scriptname
* Name of the Lua script file, without the .lua
*/
struct frrscript *frrscript_new(const char *scriptname);
/*
* Load a function into frrscript, run callback if any
*/
int frrscript_load(struct frrscript *fs, const char *function_name,
int (*load_cb)(struct frrscript *));
/*
* Delete Lua function states and frrscript
*/
void frrscript_delete(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);
/*
* On shutdown clean up memory associated with the scripting subsystem
*/
void frrscript_fini(void);
/*
* This macro is mapped to every (name, value) in frrscript_call,
* so this in turn maps them onto their encoders
*/
#define ENCODE_ARGS(name, value) ENCODE_ARGS_WITH_STATE(lfs->L, (value))
/*
* This macro is also mapped to every (name, value) in frrscript_call, but
* not every value can be mapped to its decoder - only those that appear
* in the returned table will. To find out if they appear in the returned
* table, first pop the value and check if its nil. Only call the decoder
* if non-nil.
*
* At the end, the only thing left on the stack should be the
* returned table.
*/
#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)
/*
* Noop function. Used below where we need a noop decoder for any type.
*/
void _lua_decode_noop(lua_State *, ...);
/*
* 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), \
int : lua_pushinteger, \
int * : lua_pushintegerp, \
long long : lua_pushinteger, \
long long * : lua_pushlonglongp, \
struct prefix * : lua_pushprefix, \
struct interface * : lua_pushinterface, \
struct in_addr * : lua_pushinaddr, \
struct in6_addr * : lua_pushin6addr, \
union sockunion * : lua_pushsockunion, \
char * : lua_pushstring_wrapper, \
struct attr * : lua_pushattr, \
struct peer * : lua_pushpeer, \
const struct prefix * : lua_pushprefix, \
const struct ipaddr * : lua_pushipaddr, \
const struct ethaddr * : lua_pushethaddr, \
const struct nexthop_group * : lua_pushnexthop_group, \
const struct nexthop * : lua_pushnexthop, \
struct zebra_dplane_ctx * : lua_pushzebra_dplane_ctx \
)((L), (value))
#define DECODE_ARGS_WITH_STATE(L, value) \
_Generic((value), \
int * : lua_decode_integerp, \
long long * : lua_decode_longlongp, \
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, \
char * : lua_decode_stringp, \
struct attr * : lua_decode_attr, \
default : _lua_decode_noop \
)((L), -1, (value))
/*
* Call Lua function state (abstraction for a single Lua function)
*
* lfs
* The Lua function to call; this should have been loaded in by
* frrscript_load(). nargs Number of arguments the function accepts
*
* Returns:
* 0 if the script ran successfully, nonzero otherwise.
*/
int _frrscript_call_lua(struct lua_function_state *lfs, int nargs);
/*
* Wrapper for calling Lua function state.
*
* The Lua function name (f) to run should have already been checked by
* frrscript_load. So this wrapper will:
* 1) Find the Lua function state, which contains the Lua state
* 2) Clear the Lua state (there may be leftovers items from previous call)
* 3) Push the Lua function (f)
* 4) Map frrscript_call arguments onto their encoder and decoders, push those
* 5) Call _frrscript_call_lua (Lua execution takes place)
* 6) Write back to frrscript_call arguments using their decoders
*
* This wrapper can be called multiple times (after one frrscript_load).
*
* fs
* The struct frrscript in which the Lua fuction was loaded into
* f
* Name of the Lua function.
*
* 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; \
}) \
: ({ \
lua_settop(lfs->L, 0); \
lua_getglobal(lfs->L, f); \
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 function
*
* fs
* The script. This script must have been run already.
* function_name
* Name of the Lua function.
* name
* Name of the result.
* This will be used as a string key to retrieve from the table that the
* Lua function returns.
* The name here should *not* appear in frrscript_call.
* lua_to
* Function pointer to a lua_to decoder function.
* This function should allocate and decode a value from the Lua state.
*
* Returns:
* A pointer to the decoded value from the Lua state, or NULL if no such
* value.
*/
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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