networking/nameif.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * nameif.c - Naming Interfaces based on MAC address for busybox.
   4  *
   5  * Written 2000 by Andi Kleen.
   6  * Busybox port 2002 by Nick Fedchik <nick@fedchik.org.ua>
   7  *                      Glenn McGrath <bug1@iinet.net.au>
   8  *
   9  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  10  */
  11
  12 #include "busybox.h"
  13 #include <syslog.h>
  14 #include <net/if.h>
  15 #include <netinet/ether.h>
  16
  17
  18 /* Older versions of net/if.h do not appear to define IF_NAMESIZE. */
  19 #ifndef IF_NAMESIZE
  20 #  ifdef IFNAMSIZ
  21 #    define IF_NAMESIZE IFNAMSIZ
  22 #  else
  23 #    define IF_NAMESIZE 16
  24 #  endif
  25 #endif
  26
  27 /* take from linux/sockios.h */
  28 #define SIOCSIFNAME     0x8923  /* set interface name */
  29
  30 /* Octets in one Ethernet addr, from <linux/if_ether.h> */
  31 #define ETH_ALEN        6
  32
  33 #ifndef ifr_newname
  34 #define ifr_newname ifr_ifru.ifru_slave
  35 #endif
  36
  37 typedef struct mactable_s {
  38         struct mactable_s *next;
  39         struct mactable_s *prev;
  40         char *ifname;
  41         struct ether_addr *mac;
  42 } mactable_t;
  43
  44 static unsigned long flags;
  45
  46 static void serror(const char *s, ...) ATTRIBUTE_NORETURN;
  47
  48 static void serror(const char *s, ...)
  49 {
  50         va_list ap;
  51
  52         va_start(ap, s);
  53
  54         if (flags & 1) {
  55                 openlog(bb_applet_name, 0, LOG_LOCAL0);
  56                 vsyslog(LOG_ERR, s, ap);
  57                 closelog();
  58         } else {
  59                 bb_verror_msg(s, ap);
  60                 putc('\n', stderr);
  61         }
  62         va_end(ap);
  63
  64         exit(EXIT_FAILURE);
  65 }
  66
  67 /* Check ascii str_macaddr, convert and copy to *mac */
  68 static struct ether_addr *cc_macaddr(const char *str_macaddr)
  69 {
  70         struct ether_addr *lmac, *mac;
  71
  72         lmac = ether_aton(str_macaddr);
  73         if (lmac == NULL)
  74                 serror("cannot parse MAC %s", str_macaddr);
  75         mac = xmalloc(ETH_ALEN);
  76         memcpy(mac, lmac, ETH_ALEN);
  77
  78         return mac;
  79 }
  80
  81 int nameif_main(int argc, char **argv)
  82 {
  83         mactable_t *clist = NULL;
  84         FILE *ifh;
  85         const char *fname = "/etc/mactab";
  86         char *line;
  87         int ctl_sk;
  88         int if_index = 1;
  89         mactable_t *ch;
  90
  91         flags = bb_getopt_ulflags(argc, argv, "sc:", &fname);
  92
  93         if ((argc - optind) & 1)
  94                 bb_show_usage();
  95
  96         if (optind < argc) {
  97                 char **a = argv + optind;
  98
  99                 while (*a) {
 100
 101                         if (strlen(*a) > IF_NAMESIZE)
 102                                 serror("interface name `%s' too long", *a);
 103                         ch = xzalloc(sizeof(mactable_t));
 104                         ch->ifname = xstrdup(*a++);
 105                         ch->mac = cc_macaddr(*a++);
 106                         if (clist)
 107                                 clist->prev = ch;
 108                         ch->next = clist;
 109                         clist = ch;
 110                 }
 111         } else {
 112                 ifh = xfopen(fname, "r");
 113
 114                 while ((line = bb_get_line_from_file(ifh)) != NULL) {
 115                         char *line_ptr;
 116                         size_t name_length;
 117
 118                         line_ptr = line + strspn(line, " \t");
 119                         if ((line_ptr[0] == '#') || (line_ptr[0] == '\n')) {
 120                                 free(line);
 121                                 continue;
 122                         }
 123                         name_length = strcspn(line_ptr, " \t");
 124                         ch = xzalloc(sizeof(mactable_t));
 125                         ch->ifname = xstrndup(line_ptr, name_length);
 126                         if (name_length > IF_NAMESIZE)
 127                                 serror("interface name `%s' too long", ch->ifname);
 128                         line_ptr += name_length;
 129                         line_ptr += strspn(line_ptr, " \t");
 130                         name_length = strspn(line_ptr, "0123456789ABCDEFabcdef:");
 131                         line_ptr[name_length] = '\0';
 132                         ch->mac = cc_macaddr(line_ptr);
 133                         if (clist)
 134                                 clist->prev = ch;
 135                         ch->next = clist;
 136                         clist = ch;
 137                         free(line);
 138                 }
 139                 fclose(ifh);
 140         }
 141
 142         if ((ctl_sk = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
 143                 serror("socket: %m");
 144
 145         while (clist) {
 146                 struct ifreq ifr;
 147
 148                 memset(&ifr, 0, sizeof(struct ifreq));
 149                 if_index++;
 150                 ifr.ifr_ifindex = if_index;
 151
 152                 /* Get ifname by index or die */
 153                 if (ioctl(ctl_sk, SIOCGIFNAME, &ifr))
 154                         break;
 155
 156                 /* Has this device hwaddr? */
 157                 if (ioctl(ctl_sk, SIOCGIFHWADDR, &ifr))
 158                         continue;
 159
 160                 /* Search for mac like in ifr.ifr_hwaddr.sa_data */
 161                 for (ch = clist; ch; ch = ch->next)
 162                         if (!memcmp(ch->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN))
 163                                 break;
 164
 165                 /* Nothing found for current ifr.ifr_hwaddr.sa_data */
 166                 if (ch == NULL)
 167                         continue;
 168
 169                 strcpy(ifr.ifr_newname, ch->ifname);
 170                 if (ioctl(ctl_sk, SIOCSIFNAME, &ifr) < 0)
 171                         serror("cannot change ifname %s to %s: %m",
 172                                    ifr.ifr_name, ch->ifname);
 173
 174                 /* Remove list entry of renamed interface */
 175                 if (ch->prev != NULL) {
 176                         (ch->prev)->next = ch->next;
 177                 } else {
 178                         clist = ch->next;
 179                 }
 180                 if (ch->next != NULL)
 181                         (ch->next)->prev = ch->prev;
 182                 if (ENABLE_FEATURE_CLEAN_UP) {
 183                         free(ch->ifname);
 184                         free(ch->mac);
 185                         free(ch);
 186                 }
 187         }
 188
 189         return 0;
 190 }