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 #ifdef _DEFAULT_NET_NAMING_SCHEME_TEST
  10 /* The primary purpose of this check is to verify that _DEFAULT_NET_NAMING_SCHEME_TEST
  11  * is a valid identifier. If an invalid name is given during configuration, this will
  12  * fail with a name error. */
  13 assert_cc(_DEFAULT_NET_NAMING_SCHEME_TEST >= 0);
  14 #endif
  15
  16 static const NamingScheme naming_schemes[] = {
  17         { "v238", NAMING_V238 },
  18         { "v239", NAMING_V239 },
  19         { "v240", NAMING_V240 },
  20         { "v241", NAMING_V241 },
  21         { "v243", NAMING_V243 },
  22         { "v245", NAMING_V245 },
  23         { "v247", NAMING_V247 },
  24         { "v249", NAMING_V249 },
  25         { "v250", NAMING_V250 },
  26         { "v251", NAMING_V251 },
  27         { "v252", NAMING_V252 },
  28         { "v253", NAMING_V253 },
  29         { "v254", NAMING_V254 },
  30         { "v255", NAMING_V255 },
  31         /* … add more schemes here, as the logic to name devices is updated … */
  32
  33         EXTRA_NET_NAMING_MAP
  34 };
  35
  36 const NamingScheme* naming_scheme_from_name(const char *name) {
  37         /* "latest" may either be defined explicitly by the extra map, in which case we will find it in
  38          * the table like any other name. After iterating through the table, we check for "latest" again,
  39          * which means that if not mapped explicitly, it maps to the last defined entry, whatever that is. */
  40
  41         for (size_t i = 0; i < ELEMENTSOF(naming_schemes); i++)
  42                 if (streq(naming_schemes[i].name, name))
  43                         return naming_schemes + i;
  44
  45         if (streq(name, "latest"))
  46                 return naming_schemes + ELEMENTSOF(naming_schemes) - 1;
  47
  48         return NULL;
  49 }
  50
  51 const NamingScheme* naming_scheme(void) {
  52         static const NamingScheme *cache = NULL;
  53         _cleanup_free_ char *buffer = NULL;
  54         const char *e, *k;
  55
  56         if (cache)
  57                 return cache;
  58
  59         /* Acquire setting from the kernel command line */
  60         (void) proc_cmdline_get_key("net.naming-scheme", 0, &buffer);
  61
  62         /* Also acquire it from an env var */
  63         e = getenv("NET_NAMING_SCHEME");
  64         if (e) {
  65                 if (*e == ':') {
  66                         /* If prefixed with ':' the kernel cmdline takes precedence */
  67                         k = buffer ?: e + 1;
  68                 } else
  69                         k = e; /* Otherwise the env var takes precedence */
  70         } else
  71                 k = buffer;
  72
  73         if (k) {
  74                 cache = naming_scheme_from_name(k);
  75                 if (cache) {
  76                         log_info("Using interface naming scheme '%s'.", cache->name);
  77                         return cache;
  78                 }
  79
  80                 log_warning("Unknown interface naming scheme '%s' requested, ignoring.", k);
  81         }
  82
  83         cache = naming_scheme_from_name(DEFAULT_NET_NAMING_SCHEME);
  84         assert(cache);
  85         log_info("Using default interface naming scheme '%s'.", cache->name);
  86
  87         return cache;
  88 }
  89
  90 static const char* const name_policy_table[_NAMEPOLICY_MAX] = {
  91         [NAMEPOLICY_KERNEL] = "kernel",
  92         [NAMEPOLICY_KEEP] = "keep",
  93         [NAMEPOLICY_DATABASE] = "database",
  94         [NAMEPOLICY_ONBOARD] = "onboard",
  95         [NAMEPOLICY_SLOT] = "slot",
  96         [NAMEPOLICY_PATH] = "path",
  97         [NAMEPOLICY_MAC] = "mac",
  98 };
  99
 100 DEFINE_STRING_TABLE_LOOKUP(name_policy, NamePolicy);
 101
 102 static const char* const alternative_names_policy_table[_NAMEPOLICY_MAX] = {
 103         [NAMEPOLICY_DATABASE] = "database",
 104         [NAMEPOLICY_ONBOARD] = "onboard",
 105         [NAMEPOLICY_SLOT] = "slot",
 106         [NAMEPOLICY_PATH] = "path",
 107         [NAMEPOLICY_MAC] = "mac",
 108 };
 109
 110 DEFINE_STRING_TABLE_LOOKUP(alternative_names_policy, NamePolicy);