#include <linux/bpf.h>
 
#include <linux/if_ether.h>
 
#include <linux/in.h>
 
#include <linux/ip.h>
 
#include <linux/if_packet.h>
 
#include <bpf/bpf_helpers.h>
 
#include <linux/if_vlan.h>
 
#include <linux/types.h>
 
#include <linux/tcp.h>
 
#include <linux/udp.h>
 
#include <bpf/bpf_helpers.h>
 
#include <bpf/bpf_endian.h>
 
 
 
static __always_inline int get_dport(void *trans_data, void *data_end, int protocol)
 
{
 
    struct tcphdr *th;
 
    struct udphdr *uh;
 
 
    switch (protocol) {
 
        case IPPROTO_TCP:
 
            th = (struct tcphdr *)trans_data;
 
            if ((void*)(th + 1) > data_end)
 
                return -1;
 
            return th->dest;
 
        case IPPROTO_UDP:
 
            uh = (struct udphdr *)trans_data;
 
            if ((void *)(uh + 1) > data_end)
 
                return -1;
 
            return uh->dest;
 
        default:
 
            return 0;
 
    }
 
 
}
 
 
SEC("mysection")
 
int myprogram(struct xdp_md *ctx) {
 
  void *data = (void *)(long)ctx->data;
 
  void *data_end = (void *)(long)ctx->data_end;
 
  char fmt[] = "source = %d \n";
 
  struct iphdr *ip;
 
  int dport;
 
  int hdport;
 
  struct ethhdr *eth = data;
 
  struct iphdr *iph = data + sizeof(struct ethhdr);
 
 
    if ((void *)(iph + 1) > data_end) {
 
        return XDP_DROP;
 
    }
 
 
  dport = get_dport(iph + 1, data_end,iph->protocol);
 
 
  if (dport == -1 || dport == bpf_htons(8000)) {
 
        bpf_trace_printk(fmt,sizeof(fmt),bpf_ntohs(dport));
 
      return XDP_DROP;
 
  }
 
 
  return XDP_PASS;
 
}
 
char _license [] SEC ("license") = "GPL";