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| author | Guillaume Nault <gnault@redhat.com> | 2021-06-25 16:33:13 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-06-28 22:44:17 +0300 |
| commit | aab1e898c26c3e4289c62b6d6482948672fab939 (patch) | |
| tree | 85943a4efc11e6f1216ac9662e5cafd089dae608 /net/ipv4/ip_gre.c | |
| parent | 730eed2772e740c30229d03e3d578cc00a5ae304 (diff) | |
| download | linux-aab1e898c26c3e4289c62b6d6482948672fab939.tar.xz | |
gre: let mac_header point to outer header only when necessary
Commit e271c7b4420d ("gre: do not keep the GRE header around in collect
medata mode") did reset the mac_header for the collect_md case. Let's
extend this behaviour to classical gre devices as well.
ipgre_header_parse() seems to be the only case that requires mac_header
to point to the outer header. We can detect this case accurately by
checking ->header_ops. For all other cases, we can reset mac_header.
This allows to push an Ethernet header to ipgre packets and redirect
them to an Ethernet device:
$ tc filter add dev gre0 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
Before this patch, this worked only for collect_md gre devices.
Now this works for regular gre devices as well. Only the special case
of gre devices that use ipgre_header_ops isn't supported.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_gre.c')
| -rw-r--r-- | net/ipv4/ip_gre.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c index a68bf4c6fe9b..12dca0c85f3c 100644 --- a/net/ipv4/ip_gre.c +++ b/net/ipv4/ip_gre.c @@ -107,6 +107,8 @@ module_param(log_ecn_error, bool, 0644); MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN"); static struct rtnl_link_ops ipgre_link_ops __read_mostly; +static const struct header_ops ipgre_header_ops; + static int ipgre_tunnel_init(struct net_device *dev); static void erspan_build_header(struct sk_buff *skb, u32 id, u32 index, @@ -364,7 +366,10 @@ static int __ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi, raw_proto, false) < 0) goto drop; - if (tunnel->dev->type != ARPHRD_NONE) + /* Special case for ipgre_header_parse(), which expects the + * mac_header to point to the outer IP header. + */ + if (tunnel->dev->header_ops == &ipgre_header_ops) skb_pop_mac_header(skb); else skb_reset_mac_header(skb); |