path: root/net/ipv4/ip_tunnel_core.c
diff options
authorTom Herbert <therbert@google.com>2014-06-04 17:20:02 -0700
committerDavid S. Miller <davem@davemloft.net>2014-06-04 22:46:38 -0700
commit7e2b10c1e52ca37fb522be49f4be367f9311d0cd (patch)
tree67fd8a9e9b90f732c45f406df145c8a149d24a53 /net/ipv4/ip_tunnel_core.c
parent77157e1973cbdb8d60bdb0ec749d6014bedc5bd5 (diff)
net: Support for multiple checksums with gso
When creating a GSO packet segment we may need to set more than one checksum in the packet (for instance a TCP checksum and UDP checksum for VXLAN encapsulation). To be efficient, we want to do checksum calculation for any part of the packet at most once. This patch adds csum_start offset to skb_gso_cb. This tracks the starting offset for skb->csum which is initially set in skb_segment. When a protocol needs to compute a transport checksum it calls gso_make_checksum which computes the checksum value from the start of transport header to csum_start and then adds in skb->csum to get the full checksum. skb->csum and csum_start are then updated to reflect the checksum of the resultant packet starting from the transport header. This patch also adds a flag to skbuff, encap_hdr_csum, which is set in *gso_segment fucntions to indicate that a tunnel protocol needs checksum calculation Signed-off-by: Tom Herbert <therbert@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/ip_tunnel_core.c')
1 files changed, 8 insertions, 0 deletions
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 847e69cbff7e..f4c987bb7e94 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -135,6 +135,14 @@ struct sk_buff *iptunnel_handle_offloads(struct sk_buff *skb,
return skb;
+ /* If packet is not gso and we are resolving any partial checksum,
+ * clear encapsulation flag. This allows setting CHECKSUM_PARTIAL
+ * on the outer header without confusing devices that implement
+ * NETIF_F_IP_CSUM with encapsulation.
+ */
+ if (csum_help)
+ skb->encapsulation = 0;
if (skb->ip_summed == CHECKSUM_PARTIAL && csum_help) {
err = skb_checksum_help(skb);
if (unlikely(err))

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