Add tests writing single 4in4 Geneve GSO frames to tun devices with
UDP tunnel offloads enabled.
tun_vnet_udptnl_proto uses a tap device:
- outer_proto_ok: an outer IPv4 header, with or without an 802.1Q tag,
is accepted.
- outer_proto_bad: an outer ethertype that does not match the declared
tunnel type (IPv6 on an IPv4 tunnel, or NSH, with or without a VLAN
tag) is rejected with EINVAL.
tun_vnet_udptnl_proto_l3 uses an IFF_TUN device with a tun_pi header,
so skb->protocol comes from userspace and there is no Ethernet header.
The outer IPv4 header carries options, as virtio_net_hdr_tnl_to_skb()
expects room for an Ethernet header before the outer transport header.
- outer_proto_ok: tun_pi and the frame agree on IPv4, accepted.
- outer_proto_bad: tun_pi claims IPv6, or the IP version of the frame
is not 4 while tun_pi claims IPv4: rejected with EINVAL.
Without the first patch of this series, both outer_proto_bad tests fail
because the kernel accepts the frames.
Signed-off-by: Eric Dumazet <edumazet@kernel.org>
Sashiko has reviewed this patch and found no issues.
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Sashiko AI review · https://sashiko.dev/#/patchset/20261104050131.629967-1-edumazet@kernel.org?part=3