source: MondoRescue/branches/stable/mindi-busybox/networking/libiproute/ll_map.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * ll_map.c
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 *
 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *
 */

#include <net/if.h> /* struct ifreq and co. */

#include "libbb.h"
#include "libnetlink.h"
#include "ll_map.h"

struct idxmap {
    struct idxmap *next;
    int            index;
    int            type;
    int            alen;
    unsigned       flags;
    unsigned char  addr[8];
    char           name[16];
};

static struct idxmap *idxmap[16];

static struct idxmap *find_by_index(int idx)
{
    struct idxmap *im;

    for (im = idxmap[idx & 0xF]; im; im = im->next)
        if (im->index == idx)
            return im;
    return NULL;
}

int ll_remember_index(struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
{
    int h;
    struct ifinfomsg *ifi = NLMSG_DATA(n);
    struct idxmap *im, **imp;
    struct rtattr *tb[IFLA_MAX+1];

    if (n->nlmsg_type != RTM_NEWLINK)
        return 0;

    if (n->nlmsg_len < NLMSG_LENGTH(sizeof(ifi)))
        return -1;

    memset(tb, 0, sizeof(tb));
    parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), IFLA_PAYLOAD(n));
    if (tb[IFLA_IFNAME] == NULL)
        return 0;

    h = ifi->ifi_index & 0xF;

    for (imp = &idxmap[h]; (im = *imp) != NULL; imp = &im->next)
        if (im->index == ifi->ifi_index)
            goto found;

    im = xmalloc(sizeof(*im));
    im->next = *imp;
    im->index = ifi->ifi_index;
    *imp = im;
 found:
    im->type = ifi->ifi_type;
    im->flags = ifi->ifi_flags;
    if (tb[IFLA_ADDRESS]) {
        int alen;
        im->alen = alen = RTA_PAYLOAD(tb[IFLA_ADDRESS]);
        if (alen > sizeof(im->addr))
            alen = sizeof(im->addr);
        memcpy(im->addr, RTA_DATA(tb[IFLA_ADDRESS]), alen);
    } else {
        im->alen = 0;
        memset(im->addr, 0, sizeof(im->addr));
    }
    strcpy(im->name, RTA_DATA(tb[IFLA_IFNAME]));
    return 0;
}

const char *ll_idx_n2a(int idx, char *buf)
{
    struct idxmap *im;

    if (idx == 0)
        return "*";
    im = find_by_index(idx);
    if (im)
        return im->name;
    snprintf(buf, 16, "if%d", idx);
    return buf;
}


const char *ll_index_to_name(int idx)
{
    static char nbuf[16];

    return ll_idx_n2a(idx, nbuf);
}

#ifdef UNUSED
int ll_index_to_type(int idx)
{
    struct idxmap *im;

    if (idx == 0)
        return -1;
    im = find_by_index(idx);
    if (im)
        return im->type;
    return -1;
}
#endif

unsigned ll_index_to_flags(int idx)
{
    struct idxmap *im;

    if (idx == 0)
        return 0;
    im = find_by_index(idx);
    if (im)
        return im->flags;
    return 0;
}

int xll_name_to_index(const char *const name)
{
    int ret = 0;
    int sock_fd;

/* caching is not warranted - no users which repeatedly call it */
#ifdef UNUSED
    static char ncache[16];
    static int icache;

    struct idxmap *im;
    int i;

    if (name == NULL)
        goto out;
    if (icache && strcmp(name, ncache) == 0) {
        ret = icache;
        goto out;
    }
    for (i = 0; i < 16; i++) {
        for (im = idxmap[i]; im; im = im->next) {
            if (strcmp(im->name, name) == 0) {
                icache = im->index;
                strcpy(ncache, name);
                ret = im->index;
                goto out;
            }
        }
    }
    /* We have not found the interface in our cache, but the kernel
     * may still know about it. One reason is that we may be using
     * module on-demand loading, which means that the kernel will
     * load the module and make the interface exist only when
     * we explicitely request it (check for dev_load() in net/core/dev.c).
     * I can think of other similar scenario, but they are less common...
     * Jean II */
#endif

    sock_fd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sock_fd) {
        struct ifreq ifr;
        int tmp;

        strncpy(ifr.ifr_name, name, IFNAMSIZ);
        ifr.ifr_ifindex = -1;
        tmp = ioctl(sock_fd, SIOCGIFINDEX, &ifr);
        close(sock_fd);
        if (tmp >= 0)
            /* In theory, we should redump the interface list
             * to update our cache, this is left as an exercise
             * to the reader... Jean II */
            ret = ifr.ifr_ifindex;
    }
/* out:*/
    if (ret <= 0)
        bb_error_msg_and_die("cannot find device \"%s\"", name);
    return ret;
}

int ll_init_map(struct rtnl_handle *rth)
{
    xrtnl_wilddump_request(rth, AF_UNSPEC, RTM_GETLINK);
    xrtnl_dump_filter(rth, ll_remember_index, &idxmap);
    return 0;
}