ipip: add GSO/TSO support

Now inet_gso_segment() is stackable, its relatively easy to
implement GSO/TSO support for IPIP

Performance results, when segmentation is done after tunnel
device (as no NIC is yet enabled for TSO IPIP support) :

Before patch :

lpq83:~# ./netperf -H 7.7.9.84 -Cc
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.9.84 () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

 87380  16384  16384    10.00      3357.88   5.09     3.70     2.983   2.167

After patch :

lpq83:~# ./netperf -H 7.7.9.84 -Cc
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.9.84 () port 0 AF_INET
Recv   Send    Send                          Utilization       Service Demand
Socket Socket  Message  Elapsed              Send     Recv     Send    Recv
Size   Size    Size     Time     Throughput  local    remote   local   remote
bytes  bytes   bytes    secs.    10^6bits/s  % S      % S      us/KB   us/KB

 87380  16384  16384    10.00      7710.19   4.52     6.62     1.152   1.687

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 5 deletions

diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index 7f80fb4b82d3..fe3e9f7f1f0b 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -220,17 +220,17 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
         if (unlikely(skb->protocol != htons(ETH_P_IP)))
                 goto tx_error;
 
-        if (likely(!skb->encapsulation)) {
-                skb_reset_inner_headers(skb);
-                skb->encapsulation = 1;
-        }
+        skb = iptunnel_handle_offloads(skb, false, SKB_GSO_IPIP);
+        if (IS_ERR(skb))
+                goto out;
 
         ip_tunnel_xmit(skb, dev, tiph, tiph->protocol);
         return NETDEV_TX_OK;
 
 tx_error:
-        dev->stats.tx_errors++;
         dev_kfree_skb(skb);
+out:
+        dev->stats.tx_errors++;
         return NETDEV_TX_OK;
 }
 
@@ -275,6 +275,7 @@ static const struct net_device_ops ipip_netdev_ops = {
 #define IPIP_FEATURES (NETIF_F_SG |             \
                        NETIF_F_FRAGLIST |       \
                        NETIF_F_HIGHDMA |        \
+                       NETIF_F_GSO_SOFTWARE |   \
                        NETIF_F_HW_CSUM)
 
 static void ipip_tunnel_setup(struct net_device *dev)