probe check if syn_queue is full

probe begin {
    printf("time (us)       \tacceptq\tqmax\tlocal addr\tremote_addr\n")
}

function skb_get_remote_v4addr:string(skb:long)
{
    return format_ipaddr(__ip_skb_daddr(__get_skb_iphdr(skb)), 2 /* AF_INET */)
}

function skb_get_remote_port:long(skb:long)
{
    return __tcp_skb_sport(__get_skb_tcphdr(skb))
}

// If sk_ack_backlog is larger than sk_max_ack_backlog, 
// the probe will print them and src_addr, src_port, dst_addr, dst_port
probe kernel.function("tcp_v4_conn_request") {
    if ($sk->sk_ack_backlog > $sk->sk_max_ack_backlog) {
        printf("%d\t%d\t%d\t%s:%d\t%s:%d\n",
            gettimeofday_us(),
            $sk->sk_ack_backlog,
            $sk->sk_max_ack_backlog,
            inet_get_ip_source($sk),
            inet_get_local_port($sk),
            skb_get_remote_v4addr($skb),
            skb_get_remote_port($skb));
    }
}