Print kernel stack for packet drop and consume

drop.bt

#!/usr/bin/env bpftrace


//IP_ADDRESS_DST_TO_CONVERT=127.0.0.3
//IP_ADDRESS_SRC_TO_CONVERT=127.0.0.1
//DST_HTON=$(python3 -c "import ipaddress; import socket;print(socket.htonl(int(ipaddress.ip_address('$IP_ADDRESS_DST_TO_CONVERT'))))")
//SRC_HTON=$(python3 -c "import ipaddress; import socket;print(socket.htonl(int(ipaddress.ip_address('$IP_ADDRESS_SRC_TO_CONVERT'))))")
//sudo ./drop.bt $DST_HTON $SRC_HTON
//ping 127.0.0.3
//curl 127.0.0.3

#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/byteorder/generic.h>

BEGIN
{
    printf("Trace kernel packet drops\n");
}

kprobe:kfree_skb
{
    $skb = (struct sk_buff*) arg0;
    $ipheader = ((struct iphdr *) ($skb->head + $skb->network_header));
    $version = ($ipheader->version) ;

	if ($version == 4 && $ipheader->daddr == $1 && $ipheader->saddr == $2) {
        print(kstack);
        printf("[%d] %d\t%s > %s ; %ul\n", $version, $ipheader->protocol, ntop($ipheader->saddr), ntop($ipheader->daddr), $ipheader->saddr);
    }
}

kprobe:consume_skb
{
    $skb = (struct sk_buff*) arg0;
    $ipheader = ((struct iphdr *) ($skb->head + $skb->network_header));
    $version = ($ipheader->version) ;

    if ($version == 4 && $ipheader->daddr == $1 && $ipheader->saddr == $2) {
        print(kstack);
        printf("[%d] %d\t%s > %s ; %ul\n", $version, $ipheader->protocol, ntop($ipheader->saddr), ntop($ipheader->daddr), $ipheader->saddr);
    }
}
END
{
    printf("Tracing of drops done.\n");
}