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 /* frr_default wraps information about a default that has different
  26  * values depending on FRR version or default-set
  27  *
  28  * frr_default_entry describes one match rule and the resulting value;
  29  * entries are evaluated in order and the first matching is used.
  30  *
  31  * If both match_version and match_profile are specified, they must both
  32  * match.  A NULL value matches everything.
  33  */
  34 struct frr_default_entry {
  35         /* syntax: "(<|<=|==|>=|>) [whitespace] version", e.g.
  36          *   ">= 6.1-dev" "<6.0"
  37          */
  38         const char *match_version;
  39         /* exact profile string to compare against */
  40         const char *match_profile;
  41
  42         /* value to use */
  43         bool val_bool;
  44         const char *val_str;
  45         long val_long;
  46         unsigned long val_ulong;
  47         float val_float;
  48 };
  49
  50 /* one struct frr_default exists for each malleable default value */
  51 struct frr_default {
  52         struct frr_default *next;
  53
  54         /* for UI/debug use */
  55         const char *name;
  56
  57         /* the following two sets of variables differ because the written
  58          * config always targets the *current* FRR version
  59          *
  60          * e.g. if you load a config that has "frr version 5.0" on 6.0
  61          *   *dflt_long => set to the default value in 5.0
  62          *   *save_long => set to the default value in 6.0
  63          * config save will write "frr version 6.0" with 6.0 defaults
  64          */
  65
  66         /* variable holding the default value for reading/use */
  67         bool *dflt_bool;
  68         const char **dflt_str;
  69         long *dflt_long;
  70         unsigned long *dflt_ulong;
  71         float *dflt_float;
  72
  73         /* variable to use when comparing for config save */
  74         bool *save_bool;
  75         const char **save_str;
  76         long *save_long;
  77         unsigned long *save_ulong;
  78         float *save_float;
  79
  80         struct frr_default_entry entries[];
  81 };
  82
  83 #define _FRR_CFG_DEFAULT(type, typname, varname, ...) \
  84         static type DFLT_##varname;                                            \
  85         static type SAVE_##varname;                                            \
  86         static struct frr_default _dflt_##varname = {                          \
  87                 .name = #varname,                                              \
  88                 .dflt_##typname = &DFLT_##varname,                             \
  89                 .save_##typname = &SAVE_##varname,                             \
  90                 .entries = { __VA_ARGS__ },                                    \
  91         };                                                                     \
  92         static void _dfltinit_##varname(void)                                  \
  93                 __attribute__((_CONSTRUCTOR(1000)));                           \
  94         static void _dfltinit_##varname(void)                                  \
  95         {                                                                      \
  96                 frr_default_add(&_dflt_##varname);                             \
  97         }
  98
  99 /* use:
 100  *   FRR_CFG_DEFAULT_LONG(SHARP_BLUNTNESS,
 101  *      { .val_long = 2, .match_version = ">= 10.0" },
 102  *      { .val_long = 1, .match_profile = "datacenter" },
 103  *      { .val_long = 0 },
 104  *   )
 105  *
 106  * This will create DFLT_SHARP_BLUNTNESS and SAVE_SHARP_BLUNTNESS variables.
 107  *
 108  * Note: preprocessor defines cannot be used as variable names because they
 109  * will be expanded and blow up with a compile error.  Use an enum or add an
 110  * extra _ at the beginning (e.g. _SHARP_BLUNTNESS => DFLT__SHARP_BLUNTNESS)
 111  */
 112 #define FRR_CFG_DEFAULT_BOOL(varname, ...) \
 113         _FRR_CFG_DEFAULT(bool, bool, varname, ## __VA_ARGS__)
 114 #define FRR_CFG_DEFAULT_LONG(varname, ...) \
 115         _FRR_CFG_DEFAULT(long, long, varname, ## __VA_ARGS__)
 116 #define FRR_CFG_DEFAULT_ULONG(varname, ...) \
 117         _FRR_CFG_DEFAULT(unsigned long, ulong, varname, ## __VA_ARGS__)
 118 #define FRR_CFG_DEFAULT_FLOAT(varname, ...) \
 119         _FRR_CFG_DEFAULT(float, float, varname, ## __VA_ARGS__)
 120 #define FRR_CFG_DEFAULT_STR(varname, ...) \
 121         _FRR_CFG_DEFAULT(const char *, str, varname, ## __VA_ARGS__)
 122
 123
 124 /* daemons don't need to call any of these, libfrr handles that */
 125 extern void frr_default_add(struct frr_default *dflt);
 126 extern void frr_defaults_version_set(const char *version);
 127 extern void frr_defaults_profile_set(const char *profile);
 128 extern const char *frr_defaults_version(void);
 129 extern const char *frr_defaults_profile(void);
 130 extern void frr_defaults_apply(void);
 131
 132 extern const char *frr_defaults_profiles[];
 133 extern bool frr_defaults_profile_valid(const char *profile);
 134
 135 /* like strcmp(), but with version ordering */
 136 extern int frr_version_cmp(const char *aa, const char *bb);
 137
 138 #endif /* _FRR_DEFAULTS_H */