nameif.c

   1 /*
   2  * Name Interfaces based on MAC address.
   3  * Writen 2000 by Andi Kleen.
   4  * Subject to the Gnu Public License, version 2.
   5  * TODO: make it support token ring etc.
   6  * $Id: nameif.c,v 1.4 2003/09/11 03:46:49 ak Exp $
   7  */
   8 #ifndef _GNU_SOURCE
   9 #define _GNU_SOURCE
  10 #endif
  11 #include <stdio.h>
  12 #include <getopt.h>
  13 #include <sys/syslog.h>
  14 #include <errno.h>
  15 #include <stdlib.h>
  16 #include <ctype.h>
  17 #include <string.h>
  18 #include <stdarg.h>
  19 #include <sys/socket.h>
  20 #include <sys/ioctl.h>
  21 #include <net/if.h>
  22 #include <linux/sockios.h>
  23 #include <errno.h>
  24 #include "intl.h"
  25
  26 const char default_conf[] = "/etc/mactab";
  27 const char *fname = default_conf;
  28 int use_syslog;
  29 int ctl_sk = -1;
  30
  31 void err(char *msg)
  32 {
  33         if (use_syslog) {
  34                 syslog(LOG_ERR,"%s: %m", msg);
  35         } else {
  36                 perror(msg);
  37         }
  38         exit(1);
  39 }
  40
  41 void complain(char *fmt, ...)
  42 {
  43         va_list ap;
  44         va_start(ap,fmt);
  45         if (use_syslog) {
  46                 vsyslog(LOG_ERR,fmt,ap);
  47         } else {
  48                 vfprintf(stderr,fmt,ap);
  49                 fputc('\n',stderr);
  50         }
  51         va_end(ap);
  52         exit(1);
  53 }
  54
  55 void warning(char *fmt, ...)
  56 {
  57         va_list ap;
  58         va_start(ap,fmt);
  59         if (use_syslog) {
  60                 vsyslog(LOG_ERR,fmt,ap);
  61         } else {
  62                 vfprintf(stderr,fmt,ap);
  63                 fputc('\n',stderr);
  64         }
  65         va_end(ap);
  66 }
  67
  68 int parsemac(char *str, unsigned char *mac)
  69 {
  70         char *s;
  71         while ((s = strsep(&str, ":")) != NULL) {
  72                 unsigned byte;
  73                 if (sscanf(s,"%x", &byte)!=1 || byte > 0xff)
  74                         return -1;
  75                 *mac++ = byte;
  76         }
  77         return 0;
  78 }
  79
  80 void *xmalloc(unsigned sz)
  81 {
  82         void *p = calloc(sz,1);
  83         if (!p) errno=ENOMEM, err("xmalloc");
  84         return p;
  85 }
  86
  87 void opensock(void)
  88 {
  89         if (ctl_sk < 0)
  90                 ctl_sk = socket(PF_INET,SOCK_DGRAM,0);
  91 }
  92
  93 #ifndef ifr_newname
  94 #define ifr_newname ifr_ifru.ifru_slave
  95 #endif
  96
  97 int  setname(char *oldname, char *newname)
  98 {
  99         struct ifreq ifr;
 100         opensock();
 101         memset(&ifr,0,sizeof(struct ifreq));
 102         strcpy(ifr.ifr_name, oldname);
 103         strcpy(ifr.ifr_newname, newname);
 104         return ioctl(ctl_sk, SIOCSIFNAME, &ifr);
 105 }
 106
 107 int getmac(char *name, unsigned char *mac)
 108 {
 109         int r;
 110         struct ifreq ifr;
 111         opensock();
 112         memset(&ifr,0,sizeof(struct ifreq));
 113         strcpy(ifr.ifr_name, name);
 114         r = ioctl(ctl_sk, SIOCGIFHWADDR, &ifr);
 115         memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
 116         return r;
 117 }
 118
 119 struct change {
 120         struct change *next;
 121         int found;
 122         char ifname[IFNAMSIZ+1];
 123         unsigned char mac[6];
 124 };
 125 struct change *clist;
 126
 127 struct change *lookupmac(unsigned char *mac)
 128 {
 129         struct change *ch;
 130         for (ch = clist;ch;ch = ch->next)
 131                 if (!memcmp(ch->mac, mac, 6))
 132                         return ch;
 133         return NULL;
 134 }
 135
 136 int addchange(char *p, struct change *ch, char *pos)
 137 {
 138         if (strchr(ch->ifname, ':'))
 139                 warning(_("alias device %s at %s probably has no mac"),
 140                         ch->ifname, pos);
 141         if (parsemac(p,ch->mac) < 0)
 142                 complain(_("cannot parse MAC `%s' at %s"), p, pos);
 143         ch->next = clist;
 144         clist = ch;
 145         return 0;
 146 }
 147
 148 void readconf(void)
 149 {
 150         char *line;
 151         size_t linel;
 152         int linenum;
 153         FILE *ifh;
 154         char *p;
 155         int n;
 156
 157         ifh = fopen(fname, "r");
 158         if (!ifh)
 159                 complain(_("opening configuration file %s: %s"),fname,strerror(errno));
 160
 161         line = NULL;
 162         linel = 0;
 163         linenum = 1;
 164         while (getdelim(&line, &linel, '\n', ifh) > 0) {
 165                 struct change *ch = xmalloc(sizeof(struct change));
 166                 char pos[20];
 167
 168                 sprintf(pos, _("line %d"), linenum);
 169
 170                 if ((p = strchr(line,'#')) != NULL)
 171                         *p = '\0';
 172                 p = line;
 173                 while (isspace(*p))
 174                         ++p;
 175                 if (*p == '\0')
 176                         continue;
 177                 n = strcspn(p, " \t");
 178                 if (n > IFNAMSIZ-1)
 179                         complain(_("interface name too long at line %d"), line);
 180                 memcpy(ch->ifname, p, n);
 181                 ch->ifname[n] = 0;
 182                 p += n;
 183                 p += strspn(p, " \t");
 184                 n = strspn(p, "0123456789ABCDEFabcdef:");
 185                 p[n] = 0;
 186                 addchange(p, ch, pos);
 187                 linenum++;
 188         }
 189         fclose(ifh);
 190 }
 191
 192 struct option lopt[] = {
 193         {"syslog", 0, NULL, 's' },
 194         {"config-file", 1, NULL, 'c' },
 195         {"help", 0, NULL, '?' },
 196         {NULL},
 197 };
 198
 199 void usage(void)
 200 {
 201         fprintf(stderr, _("usage: nameif [-c configurationfile] [-s] {ifname macaddress}\n"));
 202         exit(1);
 203 }
 204
 205 int main(int ac, char **av)
 206 {
 207         FILE *ifh;
 208         char *p;
 209         int n;
 210         int linenum;
 211         char *line = NULL;
 212         size_t linel = 0;
 213
 214         for (;;) {
 215                 int c = getopt_long(ac,av,"c:s",lopt,NULL);
 216                 if (c == -1) break;
 217                 switch (c) {
 218                 default:
 219                 case '?':
 220                         usage();
 221                 case 'c':
 222                         fname = optarg;
 223                         break;
 224                 case 's':
 225                         use_syslog = 1;
 226                         break;
 227                 }
 228         }
 229
 230         if (use_syslog)
 231                 openlog("nameif",0,LOG_LOCAL0);
 232
 233         while (optind < ac) {
 234                 struct change *ch = xmalloc(sizeof(struct change));
 235                 char pos[30];
 236
 237                 if ((ac-optind) & 1)
 238                         usage();
 239                 if (strlen(av[optind])+1>IFNAMSIZ)
 240                         complain(_("interface name `%s' too long"), av[optind]);
 241                 strcpy(ch->ifname, av[optind]);
 242                 optind++;
 243                 sprintf(pos,_("argument %d"),optind);
 244                 addchange(av[optind], ch, pos);
 245                 optind++;
 246         }
 247
 248         if (!clist || fname != default_conf)
 249                 readconf();
 250
 251         ifh = fopen("/proc/net/dev", "r");
 252         if (!ifh)  complain(_("open of /proc/net/dev: %s"), strerror(errno));
 253
 254
 255         linenum = 0;
 256         while (getdelim(&line, &linel, '\n', ifh) > 0) {
 257                 struct change *ch;
 258                 unsigned char mac[6];
 259
 260                 if (linenum++ < 2)
 261                         continue;
 262
 263                 p = line;
 264                 while (isspace(*p))
 265                         ++p;
 266                 n = strcspn(p, ": \t");
 267                 p[n] = 0;
 268
 269                 if (n > IFNAMSIZ-1)
 270                         complain(_("interface name `%s' too long"), p);
 271
 272                 if (getmac(p, mac) < 0)
 273                         continue;
 274
 275                 ch = lookupmac(mac);
 276                 if (!ch)
 277                         continue;
 278
 279                 ch->found = 1;
 280                 if (strcmp(p, ch->ifname)) {
 281                         if (setname(p, ch->ifname) < 0)
 282                                 complain(_("cannot change name of %s to %s: %s"),
 283                                                 p, ch->ifname, strerror(errno));
 284                 }
 285         }
 286         fclose(ifh);
 287
 288         while (clist) {
 289                 struct change *ch = clist;
 290                 clist = clist->next;
 291                 if (!ch->found)
 292                         warning(_("interface '%s' not found"), ch->ifname);
 293                 free(ch);
 294         }
 295
 296         if (use_syslog)
 297                 closelog();
 298         return 0;
 299 }
 300