Re: [PATCH net v2 0/3] Tunneling fixes

This series fixes a problem that was reported where encapsulated packets
do not have their encapsulation offload markers stripped off when being
decapsulated. This causes a significant performance drop if the packets
are later retransmitted.

Fixing this revealed two other bugs which are also addressed as prerequisites:
 * GRO can aggregate packets for multiple layers of encapsulation which the
   stack cannot properly handle.
 * IPIP packets which are combined by GRO are not marked properly with their
   GSO type.

Note that this is based off the net-next tree as the current target for
bug fixes.

I need to backport this series to the 4.4 kernel to fix a performance issue we're seeing. The series
applies but commit a09a4c8dd1ec (tunnels: Remove encapsulation offloads on decap) breaks compilation
when CONFIG_IPV6_SIT is enabled. This is because the patch uses iptunnel_pull_header() whose usage
changed with commit 7f290c94352e (iptunnel: scrub packet in iptunnel_pull_header) which is not in 4.4.

7f290c94352e seems to be a cleanup patch which also requires c9e78efb6f66 (vxlan: move vxlan device
lookup before iptunnel_pull_header) and potentially others. Rather than pulling in a slew of cleanup
patches, I was wondering if the following from commit a09a4c8dd1ec can be rewritten without using
the 'new' iptunnel_pull_header() function:

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index f45b8ffc2840..83384308d032 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c

@@ -681,14 +681,16 @@ static int ipip6_rcv(struct sk_buff *skb)
                skb->mac_header = skb->network_header;
                skb_reset_network_header(skb);
                IPCB(skb)->flags = 0;
-               skb->protocol = htons(ETH_P_IPV6);
+               skb->dev = tunnel->dev;

                if (packet_is_spoofed(skb, iph, tunnel)) {
                        tunnel->dev->stats.rx_errors++;
                        goto out;
                }

-               __skb_tunnel_rx(skb, tunnel->dev, tunnel->net);
+               if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
+                   !net_eq(tunnel->net, dev_net(tunnel->dev))))
+                       goto out;

Thanks
...Juerg

v2: No code changes, just additional information in commit messages and
    a new cover letter.

Jesse Gross (3):
  ipip: Properly mark ipip GRO packets as encapsulated.
  tunnels: Don't apply GRO to multiple layers of encapsulation.
  tunnels: Remove encapsulation offloads on decap.

 include/linux/netdevice.h |  4 ++--
 include/net/ip_tunnels.h  | 16 ++++++++++++++++
 net/core/dev.c            |  2 +-
 net/ipv4/af_inet.c        | 24 ++++++++++++++++++++++--
 net/ipv4/fou.c            | 13 +++++++++++--
 net/ipv4/gre_offload.c    |  5 +++++
 net/ipv4/ip_tunnel_core.c |  3 ++-
 net/ipv4/udp_offload.c    |  6 +++---
 net/ipv6/ip6_offload.c    | 15 ++++++++++++++-
 net/ipv6/sit.c            |  6 ++++--
 10 files changed, 80 insertions(+), 14 deletions(-)