cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

skb_pkt_end.c (989B)

      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";