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bareudp: allow redirecting bareudp packets to eth devices

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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>
This commit is contained in:
Guillaume Nault 2021-06-25 15:33:01 +02:00 committed by David S. Miller
parent ff8744b5eb
commit 99c8719b79
1 changed files with 1 additions and 0 deletions
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1
drivers/net/bareudp.c
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@ -133,6 +133,7 @@ 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 (!IS_ENABLED(CONFIG_IPV6) || family == AF_INET)
err = IP_ECN_decapsulate(oiph, skb);