netlink issue

//// ----------- caller.c ------------------
/* includes */
int main ()
    struct wireless_stats ofs;
    while (true)
    {
        get_wireless_stats(&ofs);
        /* use retrieved data */

        sleep_seconds(10);
    }
return 0;

//// --------- wireless_stats.c -----------
/* includes */
struct wireless_stats *shared_stats;

void get_wireless_stats(struct wireless_stats *ofs)
{
    struct nl_sock *sk;
    struct nl_msg *msg;
    int family_id;
    int err;

    shared_stats = ofs;
    sk = nl_socket_alloc();
    genl_connect(sk);

    // WARNING, the docs say we must call genl_family_put() later and we don't!
    family_id = genl_ctrl_resolve(sk, "nl80211");

    nl_socket_modify_cb(sk, NL_CB_VALID, NL_CB_CUSTOM,
        stats_handler, NULL);

    // WARNING, we aren't cleaning it later.
    msg = nlmsg_alloc();
    genlmsg_put(msg, 0, 0, family_id, 0, NLM_F_DUMP, NL80211_CMD_GET_STATION, 0;
    NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, if_nametoindex("mesh0"));

    // WARNING, deprecated function. Should use nl_send_auto
    err = nl_send_auto_complete(sk, msg);
    nl_recvmsgs_default(sk);
    /*
    // Question 1 scenario
    nl_socket_free(sk);
    nlsmg_free(msg);
    */
    return 0;

    // Not sure who comes here, but it isn't part of the success workflow, and is required at compilation time.
nla_put_failure:
    nlmsg_free(msg);
    // WARNING, shouldn't I also [close and] free the socket?
    return err;
}

static int stats_handler(struct nl_msg *msg, void *arg)
{
    struct nlattr *tb[NL80211_ATTR_MAX + 1];
    struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
    struct nlattr *sinfo[NL80211_STA_INFO_MAX + 1];

    static struct nla_policy stats_policy[NL80211_STA_INFO_MAX + 1] = {
        [NL80211_STA_INFO_INACTIVE_TIME] = { .type = NLA_U32 },
        /* [ ... ] */
        [NL80211_STA_INFO_CHAIN_SIGNAL_AVG] = { .type = NLA_NESTED },
    };

    nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
          genlmsg_attrlen(gnlh, 0), NULL);

    if (!tb[NL80211_ATTR_STA_INFO]) {
        fprintf(stderr, "sta stats missing!\n");
        return NL_SKIP;
    }
    if (nla_parse_nested(sinfo, NL80211_STA_INFO_MAX,
                 tb[NL80211_ATTR_STA_INFO],
                 stats_policy)) {
        fprintf(stderr, "failed to parse nested attributes!\n");
        return NL_SKIP;
    }

    // Here I save the stats to 'shared_stats'

    if (sinfo[NL80211_STA_INFO_RX_BYTES])
        shared_stats->rx_bytes = nla_get_u32(sinfo[NL80211_STA_INFO_RX_BYTES]);

    /* [ ... ] */

    if (sinfo[NL80211_STA_INFO_PLID])
        shared_stats->mesh_plid = nla_get_u16(sinfo[NL80211_STA_INFO_PLID]);
    }

    // If I try to free 'msg' here, my program explodes at runtime

    return NL_SKIP;
}