lib/defaults.h

   1 /*
   2  * FRR switchable defaults.
   3  * Copyright (C) 2017-2019  David Lamparter for NetDEF, Inc.
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #ifndef _FRR_DEFAULTS_H
  19 #define _FRR_DEFAULTS_H
  20
  21 #include <stdbool.h>
  22
  23 #include "compiler.h"
  24
  25 #ifdef __cplusplus
  26 extern "C" {
  27 #endif
  28
  29 /* frr_default wraps information about a default that has different
  30  * values depending on FRR version or default-set
  31  *
  32  * frr_default_entry describes one match rule and the resulting value;
  33  * entries are evaluated in order and the first matching is used.
  34  *
  35  * If both match_version and match_profile are specified, they must both
  36  * match.  A NULL value matches everything.
  37  */
  38 struct frr_default_entry {
  39         /* syntax: "(<|<=|==|>=|>) [whitespace] version", e.g.
  40          *   ">= 6.1-dev" "<6.0"
  41          */
  42         const char *match_version;
  43         /* exact profile string to compare against */
  44         const char *match_profile;
  45
  46         /* value to use */
  47         bool val_bool;
  48         const char *val_str;
  49         long val_long;
  50         unsigned long val_ulong;
  51         float val_float;
  52 };
  53
  54 /* one struct frr_default exists for each malleable default value */
  55 struct frr_default {
  56         struct frr_default *next;
  57
  58         /* for UI/debug use */
  59         const char *name;
  60
  61         /* the following two sets of variables differ because the written
  62          * config always targets the *current* FRR version
  63          *
  64          * e.g. if you load a config that has "frr version 5.0" on 6.0
  65          *   *dflt_long => set to the default value in 5.0
  66          *   *save_long => set to the default value in 6.0
  67          * config save will write "frr version 6.0" with 6.0 defaults
  68          */
  69
  70         /* variable holding the default value for reading/use */
  71         bool *dflt_bool;
  72         const char **dflt_str;
  73         long *dflt_long;
  74         unsigned long *dflt_ulong;
  75         float *dflt_float;
  76
  77         /* variable to use when comparing for config save */
  78         bool *save_bool;
  79         const char **save_str;
  80         long *save_long;
  81         unsigned long *save_ulong;
  82         float *save_float;
  83
  84         struct frr_default_entry entries[];
  85 };
  86
  87 #define _FRR_CFG_DEFAULT(type, typname, varname, ...) \
  88         static type DFLT_##varname;                                            \
  89         static type SAVE_##varname;                                            \
  90         static struct frr_default _dflt_##varname = {                          \
  91                 .name = #varname,                                              \
  92                 .dflt_##typname = &DFLT_##varname,                             \
  93                 .save_##typname = &SAVE_##varname,                             \
  94                 .entries = { __VA_ARGS__ },                                    \
  95         };                                                                     \
  96         static void _dfltinit_##varname(void)                                  \
  97                 __attribute__((_CONSTRUCTOR(1000)));                           \
  98         static void _dfltinit_##varname(void)                                  \
  99         {                                                                      \
 100                 frr_default_add(&_dflt_##varname);                             \
 101         }                                                                      \
 102         MACRO_REQUIRE_SEMICOLON() /* end */
 103
 104 /* use:
 105  *   FRR_CFG_DEFAULT_LONG(SHARP_BLUNTNESS,
 106  *      { .val_long = 2, .match_version = ">= 10.0" },
 107  *      { .val_long = 1, .match_profile = "datacenter" },
 108  *      { .val_long = 0 },
 109  *   )
 110  *
 111  * This will create DFLT_SHARP_BLUNTNESS and SAVE_SHARP_BLUNTNESS variables.
 112  *
 113  * Note: preprocessor defines cannot be used as variable names because they
 114  * will be expanded and blow up with a compile error.  Use an enum or add an
 115  * extra _ at the beginning (e.g. _SHARP_BLUNTNESS => DFLT__SHARP_BLUNTNESS)
 116  */
 117 #define FRR_CFG_DEFAULT_BOOL(varname, ...) \
 118         _FRR_CFG_DEFAULT(bool, bool, varname, ## __VA_ARGS__)
 119 #define FRR_CFG_DEFAULT_LONG(varname, ...) \
 120         _FRR_CFG_DEFAULT(long, long, varname, ## __VA_ARGS__)
 121 #define FRR_CFG_DEFAULT_ULONG(varname, ...) \
 122         _FRR_CFG_DEFAULT(unsigned long, ulong, varname, ## __VA_ARGS__)
 123 #define FRR_CFG_DEFAULT_FLOAT(varname, ...) \
 124         _FRR_CFG_DEFAULT(float, float, varname, ## __VA_ARGS__)
 125 #define FRR_CFG_DEFAULT_STR(varname, ...) \
 126         _FRR_CFG_DEFAULT(const char *, str, varname, ## __VA_ARGS__)
 127
 128
 129 /* daemons don't need to call any of these, libfrr handles that */
 130 extern void frr_default_add(struct frr_default *dflt);
 131 extern void frr_defaults_version_set(const char *version);
 132 extern void frr_defaults_profile_set(const char *profile);
 133 extern const char *frr_defaults_version(void);
 134 extern const char *frr_defaults_profile(void);
 135 extern void frr_defaults_apply(void);
 136
 137 extern const char *frr_defaults_profiles[];
 138 extern bool frr_defaults_profile_valid(const char *profile);
 139
 140 /* like strcmp(), but with version ordering */
 141 extern int frr_version_cmp(const char *aa, const char *bb);
 142
 143 #ifdef __cplusplus
 144 }
 145 #endif
 146
 147 #endif /* _FRR_DEFAULTS_H */