src/shared/netif-naming-scheme.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "alloc-util.h"
   4 #include "netif-naming-scheme.h"
   5 #include "proc-cmdline.h"
   6 #include "string-util.h"
   7 #include "string-table.h"
   8
   9 static const NamingScheme naming_schemes[] = {
  10         { "v238", NAMING_V238 },
  11         { "v239", NAMING_V239 },
  12         { "v240", NAMING_V240 },
  13         { "v241", NAMING_V241 },
  14         { "v243", NAMING_V243 },
  15         { "v245", NAMING_V245 },
  16         { "v247", NAMING_V247 },
  17         { "v249", NAMING_V249 },
  18         { "v250", NAMING_V250 },
  19         { "v251", NAMING_V251 },
  20         { "v252", NAMING_V252 },
  21         { "v253", NAMING_V253 },
  22         { "v254", NAMING_V254 },
  23         { "v255", NAMING_V255 },
  24         /* … add more schemes here, as the logic to name devices is updated … */
  25
  26         EXTRA_NET_NAMING_MAP
  27 };
  28
  29 const NamingScheme* naming_scheme_from_name(const char *name) {
  30         /* "latest" may either be defined explicitly by the extra map, in which case we will find it in
  31          * the table like any other name. After iterating through the table, we check for "latest" again,
  32          * which means that if not mapped explicitly, it maps to the last defined entry, whatever that is. */
  33
  34         for (size_t i = 0; i < ELEMENTSOF(naming_schemes); i++)
  35                 if (streq(naming_schemes[i].name, name))
  36                         return naming_schemes + i;
  37
  38         if (streq(name, "latest"))
  39                 return naming_schemes + ELEMENTSOF(naming_schemes) - 1;
  40
  41         return NULL;
  42 }
  43
  44 const NamingScheme* naming_scheme(void) {
  45         static const NamingScheme *cache = NULL;
  46         _cleanup_free_ char *buffer = NULL;
  47         const char *e, *k;
  48
  49         if (cache)
  50                 return cache;
  51
  52         /* Acquire setting from the kernel command line */
  53         (void) proc_cmdline_get_key("net.naming-scheme", 0, &buffer);
  54
  55         /* Also acquire it from an env var */
  56         e = getenv("NET_NAMING_SCHEME");
  57         if (e) {
  58                 if (*e == ':') {
  59                         /* If prefixed with ':' the kernel cmdline takes precedence */
  60                         k = buffer ?: e + 1;
  61                 } else
  62                         k = e; /* Otherwise the env var takes precedence */
  63         } else
  64                 k = buffer;
  65
  66         if (k) {
  67                 cache = naming_scheme_from_name(k);
  68                 if (cache) {
  69                         log_info("Using interface naming scheme '%s'.", cache->name);
  70                         return cache;
  71                 }
  72
  73                 log_warning("Unknown interface naming scheme '%s' requested, ignoring.", k);
  74         }
  75
  76         cache = naming_scheme_from_name(DEFAULT_NET_NAMING_SCHEME);
  77         assert(cache);
  78         log_info("Using default interface naming scheme '%s'.", cache->name);
  79
  80         return cache;
  81 }
  82
  83 static const char* const name_policy_table[_NAMEPOLICY_MAX] = {
  84         [NAMEPOLICY_KERNEL]   = "kernel",
  85         [NAMEPOLICY_KEEP]     = "keep",
  86         [NAMEPOLICY_DATABASE] = "database",
  87         [NAMEPOLICY_ONBOARD]  = "onboard",
  88         [NAMEPOLICY_SLOT]     = "slot",
  89         [NAMEPOLICY_PATH]     = "path",
  90         [NAMEPOLICY_MAC]      = "mac",
  91 };
  92
  93 DEFINE_STRING_TABLE_LOOKUP(name_policy, NamePolicy);
  94
  95 static const char* const alternative_names_policy_table[_NAMEPOLICY_MAX] = {
  96         [NAMEPOLICY_DATABASE] = "database",
  97         [NAMEPOLICY_ONBOARD]  = "onboard",
  98         [NAMEPOLICY_SLOT]     = "slot",
  99         [NAMEPOLICY_PATH]     = "path",
 100         [NAMEPOLICY_MAC]      = "mac",
 101 };
 102
 103 DEFINE_STRING_TABLE_LOOKUP(alternative_names_policy, NamePolicy);