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From:   gregkh@linuxfoundation.org
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hangbin Liu <liuhangbin@gmail.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        William Tu <u9012063@gmail.com>
Subject: [PATCH 5.4 017/168] selftests/bpf: No need to drop the packet when there is no geneve opt
Date:   Mon, 15 Mar 2021 14:54:09 +0100
Message-Id: <20210315135550.908514716@linuxfoundation.org>
In-Reply-To: <20210315135550.333963635@linuxfoundation.org>
References: <20210315135550.333963635@linuxfoundation.org>
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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Hangbin Liu <liuhangbin@gmail.com>

commit 557c223b643a35effec9654958d8edc62fd2603a upstream.

In bpf geneve tunnel test we set geneve option on tx side. On rx side we
only call bpf_skb_get_tunnel_opt(). Since commit 9c2e14b48119 ("ip_tunnels:
Set tunnel option flag when tunnel metadata is present") geneve_rx() will
not add TUNNEL_GENEVE_OPT flag if there is no geneve option, which cause
bpf_skb_get_tunnel_opt() return ENOENT and _geneve_get_tunnel() in
test_tunnel_kern.c drop the packet.

As it should be valid that bpf_skb_get_tunnel_opt() return error when
there is not tunnel option, there is no need to drop the packet and
break all geneve rx traffic. Just set opt_class to 0 in this test and
keep returning TC_ACT_OK.

Fixes: 933a741e3b82 ("selftests/bpf: bpf tunnel test.")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: William Tu <u9012063@gmail.com>
Link: https://lore.kernel.org/bpf/20210224081403.1425474-1-liuhangbin@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 tools/testing/selftests/bpf/progs/test_tunnel_kern.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
+++ b/tools/testing/selftests/bpf/progs/test_tunnel_kern.c
@@ -446,10 +446,8 @@ int _geneve_get_tunnel(struct __sk_buff
 	}
 
 	ret = bpf_skb_get_tunnel_opt(skb, &gopt, sizeof(gopt));
-	if (ret < 0) {
-		ERROR(ret);
-		return TC_ACT_SHOT;
-	}
+	if (ret < 0)
+		gopt.opt_class = 0;
 
 	bpf_trace_printk(fmt, sizeof(fmt),
 			key.tunnel_id, key.remote_ipv4, gopt.opt_class);