[PATCH AUTOSEL 4.19 08/68] selftests/bpf: fix sendmsg6_prog on s390

[Sasha Levin]

From: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>

[ Upstream commit c8eee4135a456bc031d67cadc454e76880d1afd8 ]

"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>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 tools/testing/selftests/bpf/sendmsg6_prog.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/sendmsg6_prog.c b/tools/testing/selftests/bpf/sendmsg6_prog.c
index 5aeaa284fc474..a680628204108 100644
--- a/tools/testing/selftests/bpf/sendmsg6_prog.c
+++ b/tools/testing/selftests/bpf/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);
-- 
2.20.1