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 "libbb.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 int nameif_main(int argc, char **argv)
  60 {
  61         mactable_t *clist = NULL;
  62         FILE *ifh;
  63         const char *fname = "/etc/mactab";
  64         char *line;
  65         int ctl_sk;
  66         int if_index = 1;
  67         mactable_t *ch;
  68
  69         if (1 & getopt32(argv, "sc:", &fname)) {
  70                 openlog(applet_name, 0, LOG_LOCAL0);
  71                 logmode = LOGMODE_SYSLOG;
  72         }
  73
  74         if ((argc - optind) & 1)
  75                 bb_show_usage();
  76
  77         if (optind < argc) {
  78                 char **a = argv + optind;
  79
  80                 while (*a) {
  81                         if (strlen(*a) > IF_NAMESIZE)
  82                                 bb_error_msg_and_die("interface name '%s' "
  83                                             "too long", *a);
  84                         ch = xzalloc(sizeof(mactable_t));
  85                         ch->ifname = xstrdup(*a++);
  86                         ch->mac = cc_macaddr(*a++);
  87                         if (clist)
  88                                 clist->prev = ch;
  89                         ch->next = clist;
  90                         clist = ch;
  91                 }
  92         } else {
  93                 ifh = xfopen(fname, "r");
  94
  95                 while ((line = xmalloc_fgets(ifh)) != NULL) {
  96                         char *line_ptr;
  97                         size_t name_length;
  98
  99                         line_ptr = line + strspn(line, " \t");
 100                         if ((line_ptr[0] == '#') || (line_ptr[0] == '\n')) {
 101                                 free(line);
 102                                 continue;
 103                         }
 104                         name_length = strcspn(line_ptr, " \t");
 105                         ch = xzalloc(sizeof(mactable_t));
 106                         ch->ifname = xstrndup(line_ptr, name_length);
 107                         if (name_length > IF_NAMESIZE)
 108                                 bb_error_msg_and_die("interface name '%s' "
 109                                                 "too long", ch->ifname);
 110                         line_ptr += name_length;
 111                         line_ptr += strspn(line_ptr, " \t");
 112                         name_length = strspn(line_ptr, "0123456789ABCDEFabcdef:");
 113                         line_ptr[name_length] = '\0';
 114                         ch->mac = cc_macaddr(line_ptr);
 115                         if (clist)
 116                                 clist->prev = ch;
 117                         ch->next = clist;
 118                         clist = ch;
 119                         free(line);
 120                 }
 121                 fclose(ifh);
 122         }
 123
 124         ctl_sk = xsocket(PF_INET, SOCK_DGRAM, 0);
 125
 126         while (clist) {
 127                 struct ifreq ifr;
 128
 129                 memset(&ifr, 0, sizeof(struct ifreq));
 130                 if_index++;
 131                 ifr.ifr_ifindex = if_index;
 132
 133                 /* Get ifname by index or die */
 134                 if (ioctl(ctl_sk, SIOCGIFNAME, &ifr))
 135                         break;
 136
 137                 /* Has this device hwaddr? */
 138                 if (ioctl(ctl_sk, SIOCGIFHWADDR, &ifr))
 139                         continue;
 140
 141                 /* Search for mac like in ifr.ifr_hwaddr.sa_data */
 142                 for (ch = clist; ch; ch = ch->next)
 143                         if (!memcmp(ch->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN))
 144                                 break;
 145
 146                 /* Nothing found for current ifr.ifr_hwaddr.sa_data */
 147                 if (ch == NULL)
 148                         continue;
 149
 150                 strcpy(ifr.ifr_newname, ch->ifname);
 151                 ioctl_or_perror_and_die(ctl_sk, SIOCSIFNAME, &ifr,
 152                                         "cannot change ifname %s to %s",
 153                                         ifr.ifr_name, ch->ifname);
 154
 155                 /* Remove list entry of renamed interface */
 156                 if (ch->prev != NULL) {
 157                         (ch->prev)->next = ch->next;
 158                 } else {
 159                         clist = ch->next;
 160                 }
 161                 if (ch->next != NULL)
 162                         (ch->next)->prev = ch->prev;
 163                 if (ENABLE_FEATURE_CLEAN_UP) {
 164                         free(ch->ifname);
 165                         free(ch->mac);
 166                         free(ch);
 167                 }
 168         }
 169
 170         return 0;
 171 }