udp: Changes to udp_offload to support remote checksum offload
Add a new GSO type, SKB_GSO_TUNNEL_REMCSUM, which indicates remote
checksum offload being done (in this case inner checksum must not
be offloaded to the NIC).
Added logic in __skb_udp_tunnel_segment to handle remote checksum
offload case.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index a774711..0a5a70d 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -41,7 +41,8 @@
unsigned int oldlen;
bool need_csum = !!(skb_shinfo(skb)->gso_type &
SKB_GSO_UDP_TUNNEL_CSUM);
- bool offload_csum = false, dont_encap = need_csum;
+ bool remcsum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TUNNEL_REMCSUM);
+ bool offload_csum = false, dont_encap = (need_csum || remcsum);
oldlen = (u16)~skb->len;
@@ -55,6 +56,7 @@
skb->mac_len = skb_inner_network_offset(skb);
skb->protocol = new_protocol;
skb->encap_hdr_csum = need_csum;
+ skb->remcsum_offload = remcsum;
/* Try to offload checksum if possible */
offload_csum = !!(need_csum &&
@@ -108,11 +110,22 @@
uh->check = ~csum_fold((__force __wsum)
((__force u32)uh->check +
(__force u32)delta));
-
if (offload_csum) {
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
+ } else if (remcsum) {
+ /* Need to calculate checksum from scratch,
+ * inner checksums are never when doing
+ * remote_checksum_offload.
+ */
+
+ skb->csum = skb_checksum(skb, udp_offset,
+ skb->len - udp_offset,
+ 0);
+ uh->check = csum_fold(skb->csum);
+ if (uh->check == 0)
+ uh->check = CSUM_MANGLED_0;
} else {
uh->check = gso_make_checksum(skb, ~uh->check);
@@ -192,6 +205,7 @@
if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY |
SKB_GSO_UDP_TUNNEL |
SKB_GSO_UDP_TUNNEL_CSUM |
+ SKB_GSO_TUNNEL_REMCSUM |
SKB_GSO_IPIP |
SKB_GSO_GRE | SKB_GSO_GRE_CSUM |
SKB_GSO_MPLS) ||