On Fri, Aug 19, 2016 at 10:09:01AM -0700, David Ahern wrote: > As reported by Lennert the MPLS GSO code is failing to properly segment > large packets. There are a couple of problems: > > 1. the inner protocol is not set so the gso segment functions for inner > protocol layers are not getting run, and > > 2 MPLS labels for packets that use the "native" (non-OVS) MPLS code > are not properly accounted for in mpls_gso_segment. > > The MPLS GSO code was added for OVS. It is re-using skb_mac_gso_segment > to call the gso segment functions for the higher layer protocols. That > means skb_mac_gso_segment is called twice -- once with the network > protocol set to MPLS and again with the network protocol set to the > inner protocol. > > This patch sets the inner skb protocol addressing item 1 above and sets > the network_header and inner_network_header to mark where the MPLS labels > start and end. The MPLS code in OVS is also updated to set the two > network markers. > > From there the MPLS GSO code uses the difference between the network > header and the inner network header to know the size of the MPLS header > that was pushed. It then pulls the MPLS header, resets the mac_len and > protocol for the inner protocol and then calls skb_mac_gso_segment > to segment the skb. > > Afterward the inner protocol segmentation is done the skb protocol > is set to mpls for each segment and the network and mac headers > restored. > > Reported-by: Lennert Buytenhek <buyt...@wantstofly.org> > Signed-off-by: David Ahern <d...@cumulusnetworks.com> > --- > net/mpls/mpls_gso.c | 38 +++++++++++++++++++++++++++----------- > net/mpls/mpls_iptunnel.c | 4 ++++ > net/openvswitch/actions.c | 6 ++++++ > 3 files changed, 37 insertions(+), 11 deletions(-) > > diff --git a/net/mpls/mpls_gso.c b/net/mpls/mpls_gso.c > index 2055e57ed1c3..2aa4beaa0e4f 100644
... > diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c > index 1ecbd7715f6d..6d78f162a88b 100644 > --- a/net/openvswitch/actions.c > +++ b/net/openvswitch/actions.c > @@ -167,6 +167,12 @@ static int push_mpls(struct sk_buff *skb, struct > sw_flow_key *key, > skb->mac_len); > skb_reset_mac_header(skb); > > + /* for GSO: set MPLS as network header and encapsulated protocol > + * header as inner network header > + */ > + skb_set_network_header(skb, skb->mac_len); > + skb_set_inner_network_header(skb, skb->mac_len + MPLS_HLEN); > + > new_mpls_lse = (__be32 *)skb_mpls_header(skb); > *new_mpls_lse = mpls->mpls_lse; Is the above calculation correct if push_mpls() is called multiple times?
