/* 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(const struct sockaddr_nl *who UNUSED_PARAM,
                struct nlmsghdr *n,
                void *arg UNUSED_PARAM)
{
        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 > (int)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 >= 0) {
                struct ifreq ifr;
                int tmp;

                strncpy_IFNAMSIZ(ifr.ifr_name, name);
                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;
}