/* * 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