static int tcp_metrics_nl_cmd_add(struct sk_buff *skb, struct genl_info *info)
{
    struct inetpeer_addr addr;
    struct net *net = genl_info_net(info);
    struct tcp_metrics_block *tm;
    unsigned int hash;
    int nla_rem;

    struct nlattr *nla;

    printk("ADDING TCP METRIC !\n");

    // Get the address
    if (parse_nl_addr(info, &addr, &hash, 1) < 0) {
        printk("Error getting address hash.\n");
        return 0;
    }

    // Calculate the entry hash
    printk("calculating hash\n");
    hash = hash_32(hash, net->ipv4.tcp_metrics_hash_log);

    rcu_read_lock();
    spin_lock_bh(&tcp_metrics_lock);
    tm = __tcp_get_metrics(&addr, net, hash);

    if (tm == NULL) {
        printk("Entry doesn't exist create a new one\n");
        printk("Got the lock\n");
        tm = kmalloc(sizeof(*tm), GFP_ATOMIC);
        tm->tcpm_addr = addr;

        // Set the default values
        printk("setting default values\n");
        tm->tcpm_vals[TCP_METRIC_RTT] = 0;
        tm->tcpm_vals[TCP_METRIC_RTTVAR] = 0;
        tm->tcpm_vals[TCP_METRIC_SSTHRESH] = 0;
        tm->tcpm_vals[TCP_METRIC_CWND] = 0;
        tm->tcpm_vals[TCP_METRIC_REORDERING] = 0;
        tm->tcpm_ts = 0;
        tm->tcpm_ts_stamp = 0;
        tm->tcpm_fastopen.mss = 0;
        tm->tcpm_fastopen.syn_loss = 0;
        tm->tcpm_fastopen.cookie.len = 0;

        // Add the entry to the hashtable
        printk("adding entry to hashtable\n");
        tm->tcpm_next = net->ipv4.tcp_metrics_hash[hash].chain;
        printk("assigning pointer\n");
        rcu_assign_pointer(net->ipv4.tcp_metrics_hash[hash].chain, tm);
    } else {
        printk("Updating existing entry\n");
    }

    printk("updating jiffies\n");
    tm->tcpm_stamp = jiffies;

    // Read the metrics from the incoming packet
    printk("reading attributes\n");
    nla_for_each_nested(nla, info->attrs[TCP_METRICS_ATTR_VALS], nla_rem) {
        printk("metric %d = %d\n", nla_type(nla), nla_get_u32(nla));
        tm->tcpm_vals[nla_type(nla) - 1] = nla_get_u32(nla);
    }

    printk("unlock\n");
    spin_unlock_bh(&tcp_metrics_lock);

    return 0;
}