On Thu, Feb 14, 2019 at 10:33 AM Eric Leblond <eric@xxxxxxxxx> wrote:
>
> Hello,
>
> On Wed, 2019-02-13 at 20:46 +0100, Eric Leblond wrote:
> > Hello,
> >
> > I've got a simple socket filter program that seems to interrupt when
> > calling the load_word construct. I'm seeing the first message but
> > never
> > the second one.
> >
> > The code is the following
> >
> > int SEC("filter") hashfilter(struct __sk_buff *skb) {
> > __u32 nhoff = BPF_LL_OFF + ETH_HLEN;
>
> So it seems the problem was coming from this line. Removing BPF_LL_OFF
> fixes the problem for kernel starting 4.18.
Maybe removing BPF_LL_OFF should work for all kernels?
>
> Is this a known issue ?
>
> Is there something that would allow a BPF file to work independently of
> the kernel version ?
>
> > __u32 ip = 0;
> > __u32 *value = NULL;
> > #if 1
> > char fmtrei[] = "word load\n";
> > bpf_trace_printk(fmtrei, sizeof(fmtrei));
> > #endif
> > ip = load_word(skb, nhoff + offsetof(struct iphdr, saddr));
> > #if 1
> > char fmti[] = "work done\n";
> > bpf_trace_printk(fmti, sizeof(fmti));
> > #endif
>
> > In 4.18 and above this is not working but older kernel were ok.
> >
> > Any suggestion will be appreciated.
> >
> > Best regards,
>
> BR,
> --
> Eric Leblond <eric@xxxxxxxxx>
>
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