networking/nameif.c

   1 /*
   2  * nameif.c - Naming Interfaces based on MAC address for busybox.
   3  *
   4  * Writen 2000 by Andi Kleen.
   5  * Busybox port 2002 by Nick Fedchik <nick@fedchik.org.ua>
   6  *                      Glenn McGrath <bug1@optushome.com.au>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  21  * 02111-1307 USA
  22  *
  23  */
  24
  25
  26 #include <sys/syslog.h>
  27 #include <sys/socket.h>
  28 #include <sys/ioctl.h>
  29 #include <errno.h>
  30 #include <getopt.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <net/if.h>
  34 #include <netinet/ether.h>
  35 #include <linux/sockios.h>
  36
  37 #include "busybox.h"
  38
  39 /* Octets in one ethernet addr, from <linux/if_ether.h>  */
  40 #define ETH_ALEN        6
  41
  42 #ifndef ifr_newname
  43 #define ifr_newname ifr_ifru.ifru_slave
  44 #endif
  45
  46 typedef struct mactable_s {
  47         struct mactable_s *next;
  48         struct mactable_s *prev;
  49         char *ifname;
  50         struct ether_addr *mac;
  51 } mactable_t;
  52
  53 static void serror(const char use_syslog, const char *s, ...)
  54 {
  55         va_list ap;
  56
  57         va_start(ap, s);
  58
  59         if (use_syslog) {
  60                 openlog("nameif", 0, LOG_LOCAL0);
  61                 syslog(LOG_ERR, s, ap);
  62                 closelog();
  63         } else {
  64                 vfprintf(stderr, s, ap);
  65                 putc('\n', stderr);
  66         }
  67
  68         va_end(ap);
  69
  70         exit(EXIT_FAILURE);
  71 }
  72
  73 /* Check ascii str_macaddr, convert and copy to *mac */
  74 struct ether_addr *cc_macaddr(char *str_macaddr, unsigned char use_syslog)
  75 {
  76         struct ether_addr *lmac, *mac;
  77
  78         lmac = ether_aton(str_macaddr);
  79         if (lmac == NULL)
  80                 serror(use_syslog, "cannot parse MAC %s", str_macaddr);
  81         mac = xcalloc(1, ETH_ALEN);
  82         memcpy(mac, lmac, ETH_ALEN);
  83
  84         return mac;
  85 }
  86
  87 int nameif_main(int argc, char **argv)
  88 {
  89         mactable_t *clist = NULL;
  90         FILE *ifh;
  91         char *fname = "/etc/mactab";
  92         char *line;
  93         unsigned char use_syslog = 0;
  94         int ctl_sk = -1;
  95         int opt;
  96         int if_index = 1;
  97         mactable_t *ch = NULL;
  98
  99         static struct option opts[] = {
 100                 {"syslog", 0, NULL, 's'},
 101                 {"configfile", 1, NULL, 'c'},
 102                 {NULL},
 103         };
 104
 105         while ((opt = getopt_long(argc, argv, "c:s", opts, NULL)) != -1) {
 106                 switch (opt) {
 107                 case 'c':
 108                         fname = optarg;
 109                         break;
 110                 case 's':
 111                         use_syslog = 1;
 112                         break;
 113                 default:
 114                         show_usage();
 115                 }
 116         }
 117
 118         if ((argc - optind) & 1)
 119                 show_usage();
 120
 121         if (optind < argc) {
 122                 while (optind < argc) {
 123
 124                         if (strlen(argv[optind]) > IF_NAMESIZE)
 125                                 serror(use_syslog, "interface name `%s' too long",
 126                                            argv[optind]);
 127                         optind++;
 128
 129                         ch = xcalloc(1, sizeof(mactable_t));
 130                         ch->next = NULL;
 131                         ch->prev = NULL;
 132                         ch->ifname = strdup(argv[optind - 1]);
 133                         ch->mac = cc_macaddr(argv[optind], use_syslog);
 134                         optind++;
 135                         if (clist)
 136                                 clist->prev = ch->next;
 137                         ch->next = clist;
 138                         ch->prev = clist;
 139                         clist = ch;
 140                 }
 141         } else {
 142                 ifh = xfopen(fname, "r");
 143
 144                 while ((line = get_line_from_file(ifh)) != NULL) {
 145                         char *line_ptr;
 146                         unsigned short name_length;
 147
 148                         line_ptr = line + strspn(line, " \t");
 149                         if ((line_ptr[0] == '#') || (line_ptr[0] == '\n'))
 150                                 continue;
 151                         name_length = strcspn(line_ptr, " \t");
 152                         if (name_length > IF_NAMESIZE)
 153                                 serror(use_syslog, "interface name `%s' too long",
 154                                            argv[optind]);
 155                         ch = xcalloc(1, sizeof(mactable_t));
 156                         ch->next = NULL;
 157                         ch->prev = NULL;
 158                         ch->ifname = strndup(line_ptr, name_length);
 159                         line_ptr += name_length;
 160                         line_ptr += strspn(line_ptr, " \t");
 161                         name_length = strspn(line_ptr, "0123456789ABCDEFabcdef:");
 162                         line_ptr[name_length] = '\0';
 163                         ch->mac = cc_macaddr(line_ptr, use_syslog);
 164                         if (clist)
 165                                 clist->prev = ch;
 166                         ch->next = clist;
 167                         clist = ch;
 168                         free(line);
 169                 }
 170                 fclose(ifh);
 171         }
 172
 173         if ((ctl_sk = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
 174                 serror(use_syslog, "socket: %s", strerror(errno));
 175
 176         while (clist) {
 177                 struct ifreq ifr;
 178
 179                 bzero(&ifr, sizeof(struct ifreq));
 180                 if_index++;
 181                 ifr.ifr_ifindex = if_index;
 182
 183                 /* Get ifname by index or die */
 184                 if (ioctl(ctl_sk, SIOCGIFNAME, &ifr))
 185                         break;
 186
 187                 /* Has this device hwaddr? */
 188                 if (ioctl(ctl_sk, SIOCGIFHWADDR, &ifr))
 189                         continue;
 190
 191                 /* Search for mac like in ifr.ifr_hwaddr.sa_data */
 192                 for (ch = clist; ch; ch = ch->next)
 193                         if (!memcmp(ch->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN))
 194                                 break;
 195
 196                 /* Nothing found for current ifr.ifr_hwaddr.sa_data */
 197                 if (ch == NULL)
 198                         continue;
 199
 200                 strcpy(ifr.ifr_newname, ch->ifname);
 201                 if (ioctl(ctl_sk, SIOCSIFNAME, &ifr) < 0)
 202                         serror(use_syslog, "cannot change ifname %s to %s: %s",
 203                                    ifr.ifr_name, ch->ifname, strerror(errno));
 204
 205                 /* Remove list entry of renamed interface */
 206                 if (ch->prev != NULL) {
 207                         (ch->prev)->next = ch->next;
 208                 } else {
 209                         clist = ch->next;
 210                 }
 211                 if (ch->next != NULL)
 212                         (ch->next)->prev = ch->prev;
 213                 free(ch);
 214         }
 215
 216         while (clist) {
 217                 ch = clist;
 218                 clist = clist->next;
 219                 free(ch);
 220         }
 221
 222         return 0;
 223 }