[PATCH v9 net-next 3/7] openvswitch: add support to push and pop mpls for layer3 packets

[Simon Horman]

Allow push and pop mpls actions to act on layer 3 packets by teaching
them not to access non-existent L2 headers of such packets.

Signed-off-by: Simon Horman <simon.hor...@netronome.com>
---
v9
* New Patch
---
 net/openvswitch/actions.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 879185fe183f..fe885a89f501 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -160,8 +160,10 @@ static int push_mpls(struct sk_buff *skb, struct 
sw_flow_key *key,
 
        skb_postpush_rcsum(skb, new_mpls_lse, MPLS_HLEN);
 
-       hdr = eth_hdr(skb);
-       hdr->h_proto = mpls->mpls_ethertype;
+       if (skb->mac_len) {
+               hdr = eth_hdr(skb);
+               hdr->h_proto = mpls->mpls_ethertype;
+       }
 
        if (!skb->inner_protocol)
                skb_set_inner_protocol(skb, skb->protocol);
@@ -174,7 +176,6 @@ static int push_mpls(struct sk_buff *skb, struct 
sw_flow_key *key,
 static int pop_mpls(struct sk_buff *skb, struct sw_flow_key *key,
                    const __be16 ethertype)
 {
-       struct ethhdr *hdr;
        int err;
 
        err = skb_ensure_writable(skb, skb->mac_len + MPLS_HLEN);
@@ -189,11 +190,16 @@ static int pop_mpls(struct sk_buff *skb, struct 
sw_flow_key *key,
        __skb_pull(skb, MPLS_HLEN);
        skb_reset_mac_header(skb);
 
-       /* skb_mpls_header() is used to locate the ethertype
-        * field correctly in the presence of VLAN tags.
-        */
-       hdr = (struct ethhdr *)(skb_mpls_header(skb) - ETH_HLEN);
-       hdr->h_proto = ethertype;
+       if (skb->mac_len) {
+               /* skb_mpls_header() is used to locate the ethertype
+                * field correctly in the presence of VLAN tags.
+                */
+               struct ethhdr *hdr;
+
+               hdr = (struct ethhdr *)(skb_mpls_header(skb) - ETH_HLEN);
+               BUG_ON((unsigned char *)hdr < skb_mac_header(skb));
+               hdr->h_proto = ethertype;
+       }
        if (eth_p_mpls(skb->protocol))
                skb->protocol = ethertype;
 
-- 
2.7.0.rc3.207.g0ac5344