net: Add GRO support for UDP encapsulating protocols

Add GRO handlers for protocols that do UDP encapsulation, with the intent of
being able to coalesce packets which encapsulate packets belonging to
the same TCP session.

For GRO purposes, the destination UDP port takes the role of the ether type
field in the ethernet header or the next protocol in the IP header.

The UDP GRO handler will only attempt to coalesce packets whose destination
port is registered to have gro handler.

Use a mark on the skb GRO CB data to disallow (flush) running the udp gro receive
code twice on a packet. This solves the problem of udp encapsulated packets whose
inner VM packet is udp and happen to carry a port which has registered offloads.

Signed-off-by: Shlomo Pongratz <shlomop@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 83ce2aee65e6..c31022980e18 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1675,7 +1675,10 @@ struct napi_gro_cb {
         unsigned long age;
 
         /* Used in ipv6_gro_receive() */
-        int     proto;
+        u16     proto;
+
+        /* Used in udp_gro_receive */
+        u16     udp_mark;
 
         /* used to support CHECKSUM_COMPLETE for tunneling protocols */
         __wsum  csum;
@@ -1714,6 +1717,11 @@ struct packet_offload {
         struct list_head         list;
 };
 
+struct udp_offload {
+        __be16                   port;
+        struct offload_callbacks callbacks;
+};
+
 /* often modified stats are per cpu, other are shared (netdev->stats) */
 struct pcpu_sw_netstats {
         u64     rx_packets;