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
   8  * Extended matching support 2008 by Nico Erfurth <masta@perlgolf.de>
   9  *
  10  * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
  11  */
  12
  13 #include "libbb.h"
  14 #include <syslog.h>
  15 #include <net/if.h>
  16 #include <netinet/ether.h>
  17 #include <linux/sockios.h>
  18
  19 #ifndef IFNAMSIZ
  20 #define IFNAMSIZ 16
  21 #endif
  22
  23 /* Taken from linux/sockios.h */
  24 #define SIOCSIFNAME     0x8923  /* set interface name */
  25
  26 /* Octets in one Ethernet addr, from <linux/if_ether.h> */
  27 #define ETH_ALEN        6
  28
  29 #ifndef ifr_newname
  30 #define ifr_newname ifr_ifru.ifru_slave
  31 #endif
  32
  33 typedef struct ethtable_s {
  34         struct ethtable_s *next;
  35         struct ethtable_s *prev;
  36         char *ifname;
  37         struct ether_addr *mac;
  38 #if ENABLE_FEATURE_NAMEIF_EXTENDED
  39         char *bus_info;
  40         char *driver;
  41 #endif
  42 } ethtable_t;
  43
  44 #if ENABLE_FEATURE_NAMEIF_EXTENDED
  45 /* Cut'n'paste from ethtool.h */
  46 #define ETHTOOL_BUSINFO_LEN 32
  47 /* these strings are set to whatever the driver author decides... */
  48 struct ethtool_drvinfo {
  49         uint32_t cmd;
  50         char  driver[32]; /* driver short name, "tulip", "eepro100" */
  51         char  version[32];  /* driver version string */
  52         char  fw_version[32]; /* firmware version string, if applicable */
  53         char  bus_info[ETHTOOL_BUSINFO_LEN];  /* Bus info for this IF. */
  54         /* For PCI devices, use pci_dev->slot_name. */
  55         char  reserved1[32];
  56         char  reserved2[16];
  57         uint32_t n_stats;  /* number of u64's from ETHTOOL_GSTATS */
  58         uint32_t testinfo_len;
  59         uint32_t eedump_len; /* Size of data from ETHTOOL_GEEPROM (bytes) */
  60         uint32_t regdump_len;  /* Size of data from ETHTOOL_GREGS (bytes) */
  61 };
  62 #define ETHTOOL_GDRVINFO  0x00000003 /* Get driver info. */
  63 #endif
  64
  65
  66 static void nameif_parse_selector(ethtable_t *ch, char *selector)
  67 {
  68         struct ether_addr *lmac;
  69 #if ENABLE_FEATURE_NAMEIF_EXTENDED
  70         int found_selector = 0;
  71
  72         while (*selector) {
  73                 char *next;
  74 #endif
  75                 selector = skip_whitespace(selector);
  76 #if ENABLE_FEATURE_NAMEIF_EXTENDED
  77                 if (*selector == '\0')
  78                         break;
  79                 /* Search for the end .... */
  80                 next = skip_non_whitespace(selector);
  81                 if (*next)
  82                         *next++ = '\0';
  83                 /* Check for selectors, mac= is assumed */
  84                 if (strncmp(selector, "bus=", 4) == 0) {
  85                         ch->bus_info = xstrdup(selector + 4);
  86                         found_selector++;
  87                 } else if (strncmp(selector, "driver=", 7) == 0) {
  88                         ch->driver = xstrdup(selector + 7);
  89                         found_selector++;
  90                 } else {
  91 #endif
  92                         lmac = xmalloc(ETH_ALEN);
  93                         ch->mac = ether_aton_r(selector + (strncmp(selector, "mac=", 4) ? 0 : 4), lmac);
  94                         if (ch->mac == NULL)
  95                                 bb_error_msg_and_die("cannot parse %s", selector);
  96 #if  ENABLE_FEATURE_NAMEIF_EXTENDED
  97                         found_selector++;
  98                 };
  99                 selector = next;
 100         }
 101         if (found_selector == 0)
 102                 bb_error_msg_and_die("no selectors found for %s", ch->ifname);
 103 #endif
 104 }
 105
 106 static void prepend_new_eth_table(ethtable_t **clist, char *ifname, char *selector)
 107 {
 108         ethtable_t *ch;
 109         if (strlen(ifname) >= IFNAMSIZ)
 110                 bb_error_msg_and_die("interface name '%s' too long", ifname);
 111         ch = xzalloc(sizeof(*ch));
 112         ch->ifname = xstrdup(ifname);
 113         nameif_parse_selector(ch, selector);
 114         ch->next = *clist;
 115         if (*clist)
 116                 (*clist)->prev = ch;
 117         *clist = ch;
 118 }
 119
 120 #if ENABLE_FEATURE_CLEAN_UP
 121 static void delete_eth_table(ethtable_t *ch)
 122 {
 123         free(ch->ifname);
 124 #if ENABLE_FEATURE_NAMEIF_EXTENDED
 125         free(ch->bus_info);
 126         free(ch->driver);
 127 #endif
 128         free(ch->mac);
 129         free(ch);
 130 };
 131 #else
 132 void delete_eth_table(ethtable_t *ch);
 133 #endif
 134
 135 int nameif_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 136 int nameif_main(int argc, char **argv)
 137 {
 138         ethtable_t *clist = NULL;
 139         const char *fname = "/etc/mactab";
 140         int ctl_sk;
 141         ethtable_t *ch;
 142         parser_t *parser;
 143         char *token[2];
 144
 145         if (1 & getopt32(argv, "sc:", &fname)) {
 146                 openlog(applet_name, 0, LOG_LOCAL0);
 147                 /* Why not just "="? I assume logging to stderr
 148                  * can't hurt. 2>/dev/null if you don't like it: */
 149                 logmode |= LOGMODE_SYSLOG;
 150         }
 151         argc -= optind;
 152         argv += optind;
 153
 154         if (argc & 1)
 155                 bb_show_usage();
 156
 157         if (argc) {
 158                 while (*argv) {
 159                         char *ifname = xstrdup(*argv++);
 160                         prepend_new_eth_table(&clist, ifname, *argv++);
 161                 }
 162         } else {
 163                 parser = config_open(fname);
 164                 while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL))
 165                         prepend_new_eth_table(&clist, token[0], token[1]);
 166                 config_close(parser);
 167         }
 168
 169         ctl_sk = xsocket(PF_INET, SOCK_DGRAM, 0);
 170         parser = config_open2("/proc/net/dev", xfopen_for_read);
 171
 172         while (clist && config_read(parser, token, 2, 2, "\0: \t", PARSE_NORMAL)) {
 173                 struct ifreq ifr;
 174 #if  ENABLE_FEATURE_NAMEIF_EXTENDED
 175                 struct ethtool_drvinfo drvinfo;
 176 #endif
 177                 if (parser->lineno < 2)
 178                         continue; /* Skip the first two lines */
 179
 180                 /* Find the current interface name and copy it to ifr.ifr_name */
 181                 memset(&ifr, 0, sizeof(struct ifreq));
 182                 strncpy_IFNAMSIZ(ifr.ifr_name, token[0]);
 183
 184 #if ENABLE_FEATURE_NAMEIF_EXTENDED
 185                 /* Check for driver etc. */
 186                 memset(&drvinfo, 0, sizeof(struct ethtool_drvinfo));
 187                 drvinfo.cmd = ETHTOOL_GDRVINFO;
 188                 ifr.ifr_data = (caddr_t) &drvinfo;
 189                 /* Get driver and businfo first, so we have it in drvinfo */
 190                 ioctl(ctl_sk, SIOCETHTOOL, &ifr);
 191 #endif
 192                 ioctl(ctl_sk, SIOCGIFHWADDR, &ifr);
 193
 194                 /* Search the list for a matching device */
 195                 for (ch = clist; ch; ch = ch->next) {
 196 #if ENABLE_FEATURE_NAMEIF_EXTENDED
 197                         if (ch->bus_info && strcmp(ch->bus_info, drvinfo.bus_info) != 0)
 198                                 continue;
 199                         if (ch->driver && strcmp(ch->driver, drvinfo.driver) != 0)
 200                                 continue;
 201 #endif
 202                         if (ch->mac && memcmp(ch->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN) != 0)
 203                                 continue;
 204                         /* if we came here, all selectors have matched */
 205                         break;
 206                 }
 207                 /* Nothing found for current interface */
 208                 if (!ch)
 209                         continue;
 210
 211                 if (strcmp(ifr.ifr_name, ch->ifname) != 0) {
 212                         strcpy(ifr.ifr_newname, ch->ifname);
 213                         ioctl_or_perror_and_die(ctl_sk, SIOCSIFNAME, &ifr,
 214                                         "cannot change ifname %s to %s",
 215                                         ifr.ifr_name, ch->ifname);
 216                 }
 217                 /* Remove list entry of renamed interface */
 218                 if (ch->prev != NULL)
 219                         ch->prev->next = ch->next;
 220                 else
 221                         clist = ch->next;
 222                 if (ch->next != NULL)
 223                         ch->next->prev = ch->prev;
 224                 if (ENABLE_FEATURE_CLEAN_UP)
 225                         delete_eth_table(ch);
 226         }
 227         if (ENABLE_FEATURE_CLEAN_UP) {
 228                 for (ch = clist; ch; ch = ch->next)
 229                         delete_eth_table(ch);
 230                 config_close(parser);
 231         };
 232
 233         return 0;
 234 }