Ilya Leoshkevich <iii@xxxxxxxxxxxxx> [Fri, 2019-07-19 02:07 -0700]:
> "sendmsg6: rewrite IP & port (C)" fails on s390, because the code in
> sendmsg_v6_prog() assumes that (ctx->user_ip6[0] & 0xFFFF) refers to
> leading IPv6 address digits, which is not the case on big-endian
> machines.
>
> Since checking bitwise operations doesn't seem to be the point of the
> test, replace two short comparisons with a single int comparison.
>
> Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
Acked-by: Andrey Ignatov <rdna@xxxxxx>
IIRC I did it this way to test 16bit loads from C program, but such
loads are already tested by asm prog in test_sock_addr.c.
Thanks for the fix!
> ---
> tools/testing/selftests/bpf/progs/sendmsg6_prog.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/progs/sendmsg6_prog.c b/tools/testing/selftests/bpf/progs/sendmsg6_prog.c
> index 5aeaa284fc47..a68062820410 100644
> --- a/tools/testing/selftests/bpf/progs/sendmsg6_prog.c
> +++ b/tools/testing/selftests/bpf/progs/sendmsg6_prog.c
> @@ -41,8 +41,7 @@ int sendmsg_v6_prog(struct bpf_sock_addr *ctx)
> }
>
> /* Rewrite destination. */
> - if ((ctx->user_ip6[0] & 0xFFFF) == bpf_htons(0xFACE) &&
> - ctx->user_ip6[0] >> 16 == bpf_htons(0xB00C)) {
> + if (ctx->user_ip6[0] == bpf_htonl(0xFACEB00C)) {
> ctx->user_ip6[0] = bpf_htonl(DST_REWRITE_IP6_0);
> ctx->user_ip6[1] = bpf_htonl(DST_REWRITE_IP6_1);
> ctx->user_ip6[2] = bpf_htonl(DST_REWRITE_IP6_2);
> --
> 2.21.0
>
--
Andrey Ignatov
