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authorDavide Caratti <dcaratti@redhat.com>2019-10-12 13:55:06 +0200
committerDavid S. Miller <davem@davemloft.net>2019-10-15 17:14:48 -0700
commitdedc5a08da07874c6e0d411e7f39c5c2cf137014 (patch)
treea35485c825295bdc5f793918cb8015aaa222de01
parenta03681dd5d1bf7b0ed3aad3162f7810af4c4e05b (diff)
net: avoid errors when trying to pop MLPS header on non-MPLS packets
the following script: # tc qdisc add dev eth0 clsact # tc filter add dev eth0 egress matchall action mpls pop implicitly makes the kernel drop all packets transmitted by eth0, if they don't have a MPLS header. This behavior is uncommon: other encapsulations (like VLAN) just let the packet pass unmodified. Since the result of MPLS 'pop' operation would be the same regardless of the presence / absence of MPLS header(s) in the original packet, we can let skb_mpls_pop() return 0 when dealing with non-MPLS packets. For the OVS use-case, this is acceptable because __ovs_nla_copy_actions() already ensures that MPLS 'pop' operation only occurs with packets having an MPLS Ethernet type (and there are no other callers in current code, so the semantic change should be ok). v2: better documentation of use-cases for skb_mpls_pop(), thanks to Simon Horman Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC") Reviewed-by: Simon Horman <simon.horman@netronome.com> Acked-by: John Hurley <john.hurley@netronome.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/skbuff.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 8c178703467b..03b6809ebde4 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5536,7 +5536,7 @@ int skb_mpls_pop(struct sk_buff *skb, __be16 next_proto)
int err;
if (unlikely(!eth_p_mpls(skb->protocol)))
- return -EINVAL;
+ return 0;
err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
if (unlikely(err))