/src/frr/lib/defaults.h

Source
// SPDX-License-Identifier: ISC
/*
 * FRR switchable defaults.
 * Copyright (C) 2017-2019  David Lamparter for NetDEF, Inc.
 */

#ifndef _FRR_DEFAULTS_H
#define _FRR_DEFAULTS_H

#include <stdbool.h>

#include "compiler.h"

#ifdef __cplusplus
extern "C" {
#endif

/* frr_default wraps information about a default that has different
 * values depending on FRR version or default-set
 *
 * frr_default_entry describes one match rule and the resulting value;
 * entries are evaluated in order and the first matching is used.
 *
 * If both match_version and match_profile are specified, they must both
 * match.  A NULL value matches everything.
 */
struct frr_default_entry {
  /* syntax: "(<|<=|==|>=|>) [whitespace] version", e.g.
   *   ">= 6.1-dev" "<6.0"
   */
  const char *match_version;
  /* exact profile string to compare against */
  const char *match_profile;

  /* value to use */
  bool val_bool;
  const char *val_str;
  long val_long;
  unsigned long val_ulong;
  float val_float;
};

/* one struct frr_default exists for each malleable default value */
struct frr_default {
  struct frr_default *next;

  /* for UI/debug use */
  const char *name;

  /* the following two sets of variables differ because the written
   * config always targets the *current* FRR version
   *
   * e.g. if you load a config that has "frr version 5.0" on 6.0
   *   *dflt_long => set to the default value in 5.0
   *   *save_long => set to the default value in 6.0
   * config save will write "frr version 6.0" with 6.0 defaults
   */

  /* variable holding the default value for reading/use */
  bool *dflt_bool;
  const char **dflt_str;
  long *dflt_long;
  unsigned long *dflt_ulong;
  float *dflt_float;

  /* variable to use when comparing for config save */
  bool *save_bool;
  const char **save_str;
  long *save_long;
  unsigned long *save_ulong;
  float *save_float;

  struct frr_default_entry entries[];
};

#define _FRR_CFG_DEFAULT(type, typname, varname, ...) \
  static type DFLT_##varname;                                            \
  static type SAVE_##varname;                                            \
  static struct frr_default _dflt_##varname = {                          \
    .name = #varname,                                              \
    .dflt_##typname = &DFLT_##varname,                             \
    .save_##typname = &SAVE_##varname,                             \
    .entries = { __VA_ARGS__ },                                    \
  };                                                                     \
  static void _dfltinit_##varname(void)                                  \
    __attribute__((_CONSTRUCTOR(1000)));                           \
  static void _dfltinit_##varname(void)                                  \
  {                                                                      \
    frr_default_add(&_dflt_##varname);                             \
  }                                                                      \
  MACRO_REQUIRE_SEMICOLON() /* end */

/* use:
 *   FRR_CFG_DEFAULT_LONG(SHARP_BLUNTNESS,
 *  { .val_long = 2, .match_version = ">= 10.0" },
 *  { .val_long = 1, .match_profile = "datacenter" },
 *  { .val_long = 0 },
 *   )
 *
 * This will create DFLT_SHARP_BLUNTNESS and SAVE_SHARP_BLUNTNESS variables.
 *
 * Note: preprocessor defines cannot be used as variable names because they
 * will be expanded and blow up with a compile error.  Use an enum or add an
 * extra _ at the beginning (e.g. _SHARP_BLUNTNESS => DFLT__SHARP_BLUNTNESS)
 */
#define FRR_CFG_DEFAULT_BOOL(varname, ...) \
  _FRR_CFG_DEFAULT(bool, bool, varname, ## __VA_ARGS__)
#define FRR_CFG_DEFAULT_LONG(varname, ...) \
  _FRR_CFG_DEFAULT(long, long, varname, ## __VA_ARGS__)
#define FRR_CFG_DEFAULT_ULONG(varname, ...) \
  _FRR_CFG_DEFAULT(unsigned long, ulong, varname, ## __VA_ARGS__)
#define FRR_CFG_DEFAULT_FLOAT(varname, ...) \
  _FRR_CFG_DEFAULT(float, float, varname, ## __VA_ARGS__)
#define FRR_CFG_DEFAULT_STR(varname, ...) \
  _FRR_CFG_DEFAULT(const char *, str, varname, ## __VA_ARGS__)


/* daemons don't need to call any of these, libfrr handles that */
extern void frr_default_add(struct frr_default *dflt);
extern void frr_defaults_version_set(const char *version);
extern void frr_defaults_profile_set(const char *profile);
extern const char *frr_defaults_version(void);
extern const char *frr_defaults_profile(void);
extern void frr_defaults_apply(void);

extern const char *frr_defaults_profiles[];
extern bool frr_defaults_profile_valid(const char *profile);

/* like strcmp(), but with version ordering */
extern int frr_version_cmp(const char *aa, const char *bb);

#ifdef __cplusplus
}
#endif

#endif /* _FRR_DEFAULTS_H */

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Created: 2025-11-11 06:17