source: MondoRescue/branches/stable/mindi-busybox/networking/nameif.c@ 1247

/*
 * nameif.c - Naming Interfaces based on MAC address for busybox.
 *
 * Written 2000 by Andi Kleen.
 * Busybox port 2002 by Nick Fedchik <nick@fedchik.org.ua>
 *          Glenn McGrath <bug1@iinet.net.au>
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

#include "busybox.h"

#include <sys/syslog.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <netinet/ether.h>


/* Older versions of net/if.h do not appear to define IF_NAMESIZE. */
#ifndef IF_NAMESIZE
#  ifdef IFNAMSIZ
#    define IF_NAMESIZE IFNAMSIZ
#  else
#    define IF_NAMESIZE 16
#  endif
#endif

/* take from linux/sockios.h */
#define SIOCSIFNAME 0x8923  /* set interface name */

/* Octets in one Ethernet addr, from <linux/if_ether.h> */
#define ETH_ALEN    6

#ifndef ifr_newname
#define ifr_newname ifr_ifru.ifru_slave
#endif

typedef struct mactable_s {
    struct mactable_s *next;
    struct mactable_s *prev;
    char *ifname;
    struct ether_addr *mac;
} mactable_t;

static unsigned long flags;

static void serror(const char *s, ...) ATTRIBUTE_NORETURN;

static void serror(const char *s, ...)
{
    va_list ap;

    va_start(ap, s);

    if (flags & 1) {
        openlog(bb_applet_name, 0, LOG_LOCAL0);
        vsyslog(LOG_ERR, s, ap);
        closelog();
    } else {
        bb_verror_msg(s, ap);
        putc('\n', stderr);
    }
    va_end(ap);

    exit(EXIT_FAILURE);
}

/* Check ascii str_macaddr, convert and copy to *mac */
static struct ether_addr *cc_macaddr(const char *str_macaddr)
{
    struct ether_addr *lmac, *mac;

    lmac = ether_aton(str_macaddr);
    if (lmac == NULL)
        serror("cannot parse MAC %s", str_macaddr);
    mac = xmalloc(ETH_ALEN);
    memcpy(mac, lmac, ETH_ALEN);

    return mac;
}

int nameif_main(int argc, char **argv)
{
    mactable_t *clist = NULL;
    FILE *ifh;
    const char *fname = "/etc/mactab";
    char *line;
    int ctl_sk;
    int if_index = 1;
    mactable_t *ch;

    flags = bb_getopt_ulflags(argc, argv, "sc:", &fname);

    if ((argc - optind) & 1)
        bb_show_usage();

    if (optind < argc) {
        char **a = argv + optind;

        while (*a) {

            if (strlen(*a) > IF_NAMESIZE)
                serror("interface name `%s' too long", *a);
            ch = xzalloc(sizeof(mactable_t));
            ch->ifname = bb_xstrdup(*a++);
            ch->mac = cc_macaddr(*a++);
            if (clist)
                clist->prev = ch;
            ch->next = clist;
            clist = ch;
        }
    } else {
        ifh = bb_xfopen(fname, "r");

        while ((line = bb_get_line_from_file(ifh)) != NULL) {
            char *line_ptr;
            size_t name_length;

            line_ptr = line + strspn(line, " \t");
            if ((line_ptr[0] == '#') || (line_ptr[0] == '\n')) {
                free(line);
                continue;
            }
            name_length = strcspn(line_ptr, " \t");
            ch = xzalloc(sizeof(mactable_t));
            ch->ifname = bb_xstrndup(line_ptr, name_length);
            if (name_length > IF_NAMESIZE)
                serror("interface name `%s' too long", ch->ifname);
            line_ptr += name_length;
            line_ptr += strspn(line_ptr, " \t");
            name_length = strspn(line_ptr, "0123456789ABCDEFabcdef:");
            line_ptr[name_length] = '\0';
            ch->mac = cc_macaddr(line_ptr);
            if (clist)
                clist->prev = ch;
            ch->next = clist;
            clist = ch;
            free(line);
        }
        fclose(ifh);
    }

    if ((ctl_sk = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
        serror("socket: %m");

    while (clist) {
        struct ifreq ifr;

        memset(&ifr, 0, sizeof(struct ifreq));
        if_index++;
        ifr.ifr_ifindex = if_index;

        /* Get ifname by index or die */
        if (ioctl(ctl_sk, SIOCGIFNAME, &ifr))
            break;

        /* Has this device hwaddr? */
        if (ioctl(ctl_sk, SIOCGIFHWADDR, &ifr))
            continue;

        /* Search for mac like in ifr.ifr_hwaddr.sa_data */
        for (ch = clist; ch; ch = ch->next)
            if (!memcmp(ch->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN))
                break;

        /* Nothing found for current ifr.ifr_hwaddr.sa_data */
        if (ch == NULL)
            continue;

        strcpy(ifr.ifr_newname, ch->ifname);
        if (ioctl(ctl_sk, SIOCSIFNAME, &ifr) < 0)
            serror("cannot change ifname %s to %s: %m",
                   ifr.ifr_name, ch->ifname);

        /* Remove list entry of renamed interface */
        if (ch->prev != NULL) {
            (ch->prev)->next = ch->next;
        } else {
            clist = ch->next;
        }
        if (ch->next != NULL)
            (ch->next)->prev = ch->prev;
        if (ENABLE_FEATURE_CLEAN_UP) {
            free(ch->ifname);
            free(ch->mac);
            free(ch);
        }
    }

    return 0;
}