gue: TX support for using remote checksum offload option
Add if_tunnel flag TUNNEL_ENCAP_FLAG_REMCSUM to configure
remote checksum offload on an IP tunnel. Add logic in gue_build_header
to insert remote checksum offload option.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fou.c b/net/ipv4/fou.c
index a3b8c5b..fb0db99 100644
--- a/net/ipv4/fou.c
+++ b/net/ipv4/fou.c
@@ -562,11 +562,19 @@
bool csum = !!(e->flags & TUNNEL_ENCAP_FLAG_CSUM);
int type = csum ? SKB_GSO_UDP_TUNNEL_CSUM : SKB_GSO_UDP_TUNNEL;
struct guehdr *guehdr;
- size_t optlen = 0;
+ size_t hdrlen, optlen = 0;
__be16 sport;
void *data;
bool need_priv = false;
+ if ((e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) &&
+ skb->ip_summed == CHECKSUM_PARTIAL) {
+ csum = false;
+ optlen += GUE_PLEN_REMCSUM;
+ type |= SKB_GSO_TUNNEL_REMCSUM;
+ need_priv = true;
+ }
+
optlen += need_priv ? GUE_LEN_PRIV : 0;
skb = iptunnel_handle_offloads(skb, csum, type);
@@ -578,7 +586,9 @@
sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
skb, 0, 0, false);
- skb_push(skb, sizeof(struct guehdr) + optlen);
+ hdrlen = sizeof(struct guehdr) + optlen;
+
+ skb_push(skb, hdrlen);
guehdr = (struct guehdr *)skb->data;
@@ -597,7 +607,26 @@
*flags = 0;
data += GUE_LEN_PRIV;
- /* Add private flags */
+ if (type & SKB_GSO_TUNNEL_REMCSUM) {
+ u16 csum_start = skb_checksum_start_offset(skb);
+ __be16 *pd = data;
+
+ if (csum_start < hdrlen)
+ return -EINVAL;
+
+ csum_start -= hdrlen;
+ pd[0] = htons(csum_start);
+ pd[1] = htons(csum_start + skb->csum_offset);
+
+ if (!skb_is_gso(skb)) {
+ skb->ip_summed = CHECKSUM_NONE;
+ skb->encapsulation = 0;
+ }
+
+ *flags |= GUE_PFLAG_REMCSUM;
+ data += GUE_PLEN_REMCSUM;
+ }
+
}
fou_build_udp(skb, e, fl4, protocol, sport);