bareudp: allow redirecting bareudp packets to eth devices

[ Upstream commit 99c8719b79814cab3fd43519591dcc41c978a48c ]

Even though bareudp transports L3 data (typically IP or MPLS), it needs
to reset the mac_header pointer, so that other parts of the stack don't
mistakenly access the outer header after the packet has been
decapsulated.

This allows to push an Ethernet header to bareudp packets and redirect
them to an Ethernet device:

  $ tc filter add dev bareudp0 ingress matchall      \
      action vlan push_eth dst_mac 00:00:5e:00:53:01 \
                           src_mac 00:00:5e:00:53:00 \
      action mirred egress redirect dev eth0

Without this patch, push_eth refuses to add an ethernet header because
the skb appears to already have a MAC header.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 45fa29c85117 ("bareudp: Pull inner IP header in bareudp_udp_encap_recv().")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Guillaume Nault 2021-06-25 15:33:01 +02:00 committed by Ksawlii
parent 4fcf5af75d
commit 854b84d157

View file

@ -139,6 +139,7 @@ static int bareudp_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
skb->dev = bareudp->dev;
oiph = skb_network_header(skb);
skb_reset_network_header(skb);
skb_reset_mac_header(skb);
if (!ipv6_mod_enabled() || family == AF_INET)
err = IP_ECN_decapsulate(oiph, skb);