networking/nameif.c

   1 /*
   2  * nameif.c - Naming Interfaces based on MAC address for busybox.
   3  *
   4  * Written 2000 by Andi Kleen.
   5  * Busybox port 2002 by Nick Fedchik <nick@fedchik.org.ua>
   6  *                      Glenn McGrath <bug1@iinet.net.au>
   7  *
   8  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
   9  */
  10
  11 #include <sys/syslog.h>
  12 #include <sys/socket.h>
  13 #include <sys/ioctl.h>
  14 #include <errno.h>
  15 #include <stdlib.h>
  16 #include <string.h>
  17 #include <unistd.h>
  18 #include <net/if.h>
  19 #include <netinet/ether.h>
  20
  21 #include "busybox.h"
  22
  23 /* Older versions of net/if.h do not appear to define IF_NAMESIZE. */
  24 #ifndef IF_NAMESIZE
  25 #  ifdef IFNAMSIZ
  26 #    define IF_NAMESIZE IFNAMSIZ
  27 #  else
  28 #    define IF_NAMESIZE 16
  29 #  endif
  30 #endif
  31
  32 /* take from linux/sockios.h */
  33 #define SIOCSIFNAME     0x8923  /* set interface name */
  34
  35 /* Octets in one Ethernet addr, from <linux/if_ether.h> */
  36 #define ETH_ALEN        6
  37
  38 #ifndef ifr_newname
  39 #define ifr_newname ifr_ifru.ifru_slave
  40 #endif
  41
  42 typedef struct mactable_s {
  43         struct mactable_s *next;
  44         struct mactable_s *prev;
  45         char *ifname;
  46         struct ether_addr *mac;
  47 } mactable_t;
  48
  49 static unsigned long flags;
  50
  51 static void serror(const char *s, ...) ATTRIBUTE_NORETURN;
  52
  53 static void serror(const char *s, ...)
  54 {
  55         va_list ap;
  56
  57         va_start(ap, s);
  58
  59         if (flags & 1) {
  60                 openlog(bb_applet_name, 0, LOG_LOCAL0);
  61                 vsyslog(LOG_ERR, s, ap);
  62                 closelog();
  63         } else {
  64                 bb_verror_msg(s, ap);
  65                 putc('\n', stderr);
  66         }
  67         va_end(ap);
  68
  69         exit(EXIT_FAILURE);
  70 }
  71
  72 /* Check ascii str_macaddr, convert and copy to *mac */
  73 static struct ether_addr *cc_macaddr(const char *str_macaddr)
  74 {
  75         struct ether_addr *lmac, *mac;
  76
  77         lmac = ether_aton(str_macaddr);
  78         if (lmac == NULL)
  79                 serror("cannot parse MAC %s", str_macaddr);
  80         mac = xmalloc(ETH_ALEN);
  81         memcpy(mac, lmac, ETH_ALEN);
  82
  83         return mac;
  84 }
  85
  86 int nameif_main(int argc, char **argv)
  87 {
  88         mactable_t *clist = NULL;
  89         FILE *ifh;
  90         const char *fname = "/etc/mactab";
  91         char *line;
  92         int ctl_sk;
  93         int if_index = 1;
  94         mactable_t *ch;
  95
  96         flags = bb_getopt_ulflags(argc, argv, "sc:", &fname);
  97
  98         if ((argc - optind) & 1)
  99                 bb_show_usage();
 100
 101         if (optind < argc) {
 102                 char **a = argv + optind;
 103
 104                 while (*a) {
 105
 106                         if (strlen(*a) > IF_NAMESIZE)
 107                                 serror("interface name `%s' too long", *a);
 108                         ch = xzalloc(sizeof(mactable_t));
 109                         ch->ifname = bb_xstrdup(*a++);
 110                         ch->mac = cc_macaddr(*a++);
 111                         if (clist)
 112                                 clist->prev = ch;
 113                         ch->next = clist;
 114                         clist = ch;
 115                 }
 116         } else {
 117                 ifh = bb_xfopen(fname, "r");
 118
 119                 while ((line = bb_get_line_from_file(ifh)) != NULL) {
 120                         char *line_ptr;
 121                         size_t name_length;
 122
 123                         line_ptr = line + strspn(line, " \t");
 124                         if ((line_ptr[0] == '#') || (line_ptr[0] == '\n')) {
 125                                 free(line);
 126                                 continue;
 127                         }
 128                         name_length = strcspn(line_ptr, " \t");
 129                         ch = xzalloc(sizeof(mactable_t));
 130                         ch->ifname = bb_xstrndup(line_ptr, name_length);
 131                         if (name_length > IF_NAMESIZE)
 132                                 serror("interface name `%s' too long", ch->ifname);
 133                         line_ptr += name_length;
 134                         line_ptr += strspn(line_ptr, " \t");
 135                         name_length = strspn(line_ptr, "0123456789ABCDEFabcdef:");
 136                         line_ptr[name_length] = '\0';
 137                         ch->mac = cc_macaddr(line_ptr);
 138                         if (clist)
 139                                 clist->prev = ch;
 140                         ch->next = clist;
 141                         clist = ch;
 142                         free(line);
 143                 }
 144                 fclose(ifh);
 145         }
 146
 147         if ((ctl_sk = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
 148                 serror("socket: %m");
 149
 150         while (clist) {
 151                 struct ifreq ifr;
 152
 153                 memset(&ifr, 0, sizeof(struct ifreq));
 154                 if_index++;
 155                 ifr.ifr_ifindex = if_index;
 156
 157                 /* Get ifname by index or die */
 158                 if (ioctl(ctl_sk, SIOCGIFNAME, &ifr))
 159                         break;
 160
 161                 /* Has this device hwaddr? */
 162                 if (ioctl(ctl_sk, SIOCGIFHWADDR, &ifr))
 163                         continue;
 164
 165                 /* Search for mac like in ifr.ifr_hwaddr.sa_data */
 166                 for (ch = clist; ch; ch = ch->next)
 167                         if (!memcmp(ch->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN))
 168                                 break;
 169
 170                 /* Nothing found for current ifr.ifr_hwaddr.sa_data */
 171                 if (ch == NULL)
 172                         continue;
 173
 174                 strcpy(ifr.ifr_newname, ch->ifname);
 175                 if (ioctl(ctl_sk, SIOCSIFNAME, &ifr) < 0)
 176                         serror("cannot change ifname %s to %s: %m",
 177                                    ifr.ifr_name, ch->ifname);
 178
 179                 /* Remove list entry of renamed interface */
 180                 if (ch->prev != NULL) {
 181                         (ch->prev)->next = ch->next;
 182                 } else {
 183                         clist = ch->next;
 184                 }
 185                 if (ch->next != NULL)
 186                         (ch->next)->prev = ch->prev;
 187                 if (ENABLE_FEATURE_CLEAN_UP) {
 188                         free(ch->ifname);
 189                         free(ch->mac);
 190                         free(ch);
 191                 }
 192         }
 193
 194         return 0;
 195 }