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/*
* BIRD Internet Routing Daemon -- Filter instructions
*
* (c) 1999 Pavel Machek <pavel@ucw.cz>
* (c) 2018--2019 Maria Matejka <mq@jmq.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*
* Filter interpreter data structures and internal API.
* The filter code goes through several phases:
*
* 1 Parsing
* Flex- and Bison-generated parser decodes the human-readable data into
* a struct f_inst tree. This is an infix tree that was interpreted by
* depth-first search execution in previous versions of the interpreter.
* All instructions have their constructor: f_new_inst(FI_code, ...)
* translates into f_new_inst_FI_code(...) and the types are checked in
* compile time.
*
* 2 Linearize before interpreting
* The infix tree is always interpreted in the same order. Therefore we
* sort the instructions one after another into struct f_line. Results
* and arguments of these instructions are implicitly put on a value
* stack; e.g. the + operation just takes two arguments from the value
* stack and puts the result on there.
*
* 3 Interpret
* The given line is put on a custom execution stack. If needed (FI_CALL,
* FI_SWITCH, FI_AND, FI_OR, FI_CONDITION, ...), another line is put on top
* of the stack; when that line finishes, the execution continues on the
* older lines on the stack where it stopped before.
*
* 4 Same
* On config reload, the filters have to be compared whether channel
* reload is needed or not. The comparison is done by comparing the
* struct f_line's recursively.
*
* The main purpose of this rework was to improve filter performance
* by making the interpreter non-recursive.
*
* The other outcome is concentration of instruction definitions to
* one place -- filter/f-inst.c
*/
#ifndef _BIRD_F_INST_H_
#define _BIRD_F_INST_H_
#include "nest/bird.h"
#include "conf/conf.h"
#include "filter/filter.h"
#include "filter/data.h"
/* Flags for instructions */
enum f_instruction_flags {
FIF_PRINTED = 1, /* FI_PRINT_AND_DIE: message put in buffer */
} PACKED;
/* Include generated filter instruction declarations */
#include "filter/inst-gen.h"
#define f_new_inst(...) MACRO_CONCAT_AFTER(f_new_inst_, MACRO_FIRST(__VA_ARGS__))(__VA_ARGS__)
/* Convert the instruction back to the enum name */
const char *f_instruction_name(enum f_instruction_code fi);
/* Filter structures for execution */
/* Line of instructions to be unconditionally executed one after another */
struct f_line {
uint len; /* Line length */
u8 args; /* Function: Args required */
u8 vars;
struct f_line_item items[0]; /* The items themselves */
};
/* Convert the f_inst infix tree to the f_line structures */
struct f_line *f_linearize_concat(const struct f_inst * const inst[], uint count);
static inline struct f_line *f_linearize(const struct f_inst *root)
{ return f_linearize_concat(&root, 1); }
void f_dump_line(const struct f_line *, uint indent);
struct filter *f_new_where(struct f_inst *);
static inline struct f_dynamic_attr f_new_dynamic_attr(u8 type, u8 bit, enum f_type f_type, uint code) /* Type as core knows it, type as filters know it, and code of dynamic attribute */
{ return (struct f_dynamic_attr) { .type = type, .bit = bit, .f_type = f_type, .ea_code = code }; } /* f_type currently unused; will be handy for static type checking */
static inline struct f_static_attr f_new_static_attr(int f_type, int code, int readonly)
{ return (struct f_static_attr) { .f_type = f_type, .sa_code = code, .readonly = readonly }; }
struct f_inst *f_generate_complex(enum f_instruction_code fi_code, struct f_dynamic_attr da, struct f_inst *argument);
struct f_inst *f_generate_roa_check(struct rtable_config *table, struct f_inst *prefix, struct f_inst *asn);
/* Hook for call bt_assert() function in configuration */
extern void (*bt_assert_hook)(int result, const struct f_line_item *assert);
/* Bird Tests */
struct f_bt_test_suite {
node n; /* Node in config->tests */
const struct f_line *fn; /* Root of function */
const struct f_line *cmp; /* Compare to this function */
const char *fn_name; /* Name of test */
const char *dsc; /* Description */
int result; /* Desired result */
};
#endif
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