LXR linux/tools/testing/selftests/bpf/progs/skb_pkt

   1// SPDX-License-Identifier: GPL-2.0
   2#define BPF_NO_PRESERVE_ACCESS_INDEX
   3#include <vmlinux.h>
   4#include <bpf/bpf_core_read.h>
   5#include <bpf/bpf_helpers.h>
   6
   7#define INLINE __always_inline
   8
   9#define skb_shorter(skb, len) ((void *)(long)(skb)->data + (len) > (void *)(long)skb->data_end)
  10
  11#define ETH_IPV4_TCP_SIZE (14 + sizeof(struct iphdr) + sizeof(struct tcphdr))
  12
  13static INLINE struct iphdr *get_iphdr(struct __sk_buff *skb)
  14{
  15        struct iphdr *ip = NULL;
  16        struct ethhdr *eth;
  17
  18        if (skb_shorter(skb, ETH_IPV4_TCP_SIZE))
  19                goto out;
  20
  21        eth = (void *)(long)skb->data;
  22        ip = (void *)(eth + 1);
  23
  24out:
  25        return ip;
  26}
  27
  28SEC("tc")
  29int main_prog(struct __sk_buff *skb)
  30{
  31        struct iphdr *ip = NULL;
  32        struct tcphdr *tcp;
  33        __u8 proto = 0;
  34
  35        if (!(ip = get_iphdr(skb)))
  36                goto out;
  37
  38        proto = ip->protocol;
  39
  40        if (proto != IPPROTO_TCP)
  41                goto out;
  42
  43        tcp = (void*)(ip + 1);
  44        if (tcp->dest != 0)
  45                goto out;
  46        if (!tcp)
  47                goto out;
  48
  49        return tcp->urg_ptr;
  50out:
  51        return -1;
  52}
  53char _license[] SEC("license") = "GPL";
  54