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 /* Check ascii str_macaddr, convert and copy to *mac */
  45 static struct ether_addr *cc_macaddr(const char *str_macaddr)
  46 {
  47         struct ether_addr *lmac, *mac;
  48
  49         lmac = ether_aton(str_macaddr);
  50         if (lmac == NULL)
  51                 bb_error_msg_and_die("cannot parse MAC %s", str_macaddr);
  52         mac = xmalloc(ETH_ALEN);
  53         memcpy(mac, lmac, ETH_ALEN);
  54
  55         return mac;
  56 }
  57
  58 int nameif_main(int argc, char **argv)
  59 {
  60         mactable_t *clist = NULL;
  61         FILE *ifh;
  62         const char *fname = "/etc/mactab";
  63         char *line;
  64         int ctl_sk;
  65         int if_index = 1;
  66         mactable_t *ch;
  67
  68         if (1 & getopt32(argc, argv, "sc:", &fname)) {
  69                 openlog(applet_name, 0, LOG_LOCAL0);
  70                 logmode = LOGMODE_SYSLOG;
  71         }
  72
  73         if ((argc - optind) & 1)
  74                 bb_show_usage();
  75
  76         if (optind < argc) {
  77                 char **a = argv + optind;
  78
  79                 while (*a) {
  80                         if (strlen(*a) > IF_NAMESIZE)
  81                                 bb_error_msg_and_die("interface name `%s' "
  82                                             "too long", *a);
  83                         ch = xzalloc(sizeof(mactable_t));
  84                         ch->ifname = xstrdup(*a++);
  85                         ch->mac = cc_macaddr(*a++);
  86                         if (clist)
  87                                 clist->prev = ch;
  88                         ch->next = clist;
  89                         clist = ch;
  90                 }
  91         } else {
  92                 ifh = xfopen(fname, "r");
  93
  94                 while ((line = xmalloc_fgets(ifh)) != NULL) {
  95                         char *line_ptr;
  96                         size_t name_length;
  97
  98                         line_ptr = line + strspn(line, " \t");
  99                         if ((line_ptr[0] == '#') || (line_ptr[0] == '\n')) {
 100                                 free(line);
 101                                 continue;
 102                         }
 103                         name_length = strcspn(line_ptr, " \t");
 104                         ch = xzalloc(sizeof(mactable_t));
 105                         ch->ifname = xstrndup(line_ptr, name_length);
 106                         if (name_length > IF_NAMESIZE)
 107                                 bb_error_msg_and_die("interface name `%s' "
 108                                                 "too long", ch->ifname);
 109                         line_ptr += name_length;
 110                         line_ptr += strspn(line_ptr, " \t");
 111                         name_length = strspn(line_ptr, "0123456789ABCDEFabcdef:");
 112                         line_ptr[name_length] = '\0';
 113                         ch->mac = cc_macaddr(line_ptr);
 114                         if (clist)
 115                                 clist->prev = ch;
 116                         ch->next = clist;
 117                         clist = ch;
 118                         free(line);
 119                 }
 120                 fclose(ifh);
 121         }
 122
 123         ctl_sk = xsocket(PF_INET, SOCK_DGRAM, 0);
 124
 125         while (clist) {
 126                 struct ifreq ifr;
 127
 128                 memset(&ifr, 0, sizeof(struct ifreq));
 129                 if_index++;
 130                 ifr.ifr_ifindex = if_index;
 131
 132                 /* Get ifname by index or die */
 133                 if (ioctl(ctl_sk, SIOCGIFNAME, &ifr))
 134                         break;
 135
 136                 /* Has this device hwaddr? */
 137                 if (ioctl(ctl_sk, SIOCGIFHWADDR, &ifr))
 138                         continue;
 139
 140                 /* Search for mac like in ifr.ifr_hwaddr.sa_data */
 141                 for (ch = clist; ch; ch = ch->next)
 142                         if (!memcmp(ch->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN))
 143                                 break;
 144
 145                 /* Nothing found for current ifr.ifr_hwaddr.sa_data */
 146                 if (ch == NULL)
 147                         continue;
 148
 149                 strcpy(ifr.ifr_newname, ch->ifname);
 150                 if (ioctl(ctl_sk, SIOCSIFNAME, &ifr) < 0)
 151                         bb_perror_msg_and_die("cannot change ifname %s to %s",
 152                                    ifr.ifr_name, ch->ifname);
 153
 154                 /* Remove list entry of renamed interface */
 155                 if (ch->prev != NULL) {
 156                         (ch->prev)->next = ch->next;
 157                 } else {
 158                         clist = ch->next;
 159                 }
 160                 if (ch->next != NULL)
 161                         (ch->next)->prev = ch->prev;
 162                 if (ENABLE_FEATURE_CLEAN_UP) {
 163                         free(ch->ifname);
 164                         free(ch->mac);
 165                         free(ch);
 166                 }
 167         }
 168
 169         return 0;
 170 }