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authorAlexander Duyck <aduyck@mirantis.com>2016-04-11 04:45:03 +0300
committerDavid S. Miller <davem@davemloft.net>2016-04-14 23:23:41 +0300
commit802ab55adc39a06940a1b384e9fd0387fc762d7e (patch)
tree96aace3c09e144382c95c4a90cba3ce46eb660c0 /net/ipv4/gre_offload.c
parent1530545ed64b42e87acb43c0c16401bd1ebae6bf (diff)
downloadlinux-802ab55adc39a06940a1b384e9fd0387fc762d7e.tar.xz
GSO: Support partial segmentation offload
This patch adds support for something I am referring to as GSO partial. The basic idea is that we can support a broader range of devices for segmentation if we use fixed outer headers and have the hardware only really deal with segmenting the inner header. The idea behind the naming is due to the fact that everything before csum_start will be fixed headers, and everything after will be the region that is handled by hardware. With the current implementation it allows us to add support for the following GSO types with an inner TSO_MANGLEID or TSO6 offload: NETIF_F_GSO_GRE NETIF_F_GSO_GRE_CSUM NETIF_F_GSO_IPIP NETIF_F_GSO_SIT NETIF_F_UDP_TUNNEL NETIF_F_UDP_TUNNEL_CSUM In the case of hardware that already supports tunneling we may be able to extend this further to support TSO_TCPV4 without TSO_MANGLEID if the hardware can support updating inner IPv4 headers. Signed-off-by: Alexander Duyck <aduyck@mirantis.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/gre_offload.c')
-rw-r--r--net/ipv4/gre_offload.c26
1 files changed, 21 insertions, 5 deletions
diff --git a/net/ipv4/gre_offload.c b/net/ipv4/gre_offload.c
index 6376b0cdf693..20557f211408 100644
--- a/net/ipv4/gre_offload.c
+++ b/net/ipv4/gre_offload.c
@@ -36,7 +36,8 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
SKB_GSO_GRE |
SKB_GSO_GRE_CSUM |
SKB_GSO_IPIP |
- SKB_GSO_SIT)))
+ SKB_GSO_SIT |
+ SKB_GSO_PARTIAL)))
goto out;
if (!skb->encapsulation)
@@ -87,7 +88,7 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
skb = segs;
do {
struct gre_base_hdr *greh;
- __be32 *pcsum;
+ __sum16 *pcsum;
/* Set up inner headers if we are offloading inner checksum */
if (skb->ip_summed == CHECKSUM_PARTIAL) {
@@ -107,10 +108,25 @@ static struct sk_buff *gre_gso_segment(struct sk_buff *skb,
continue;
greh = (struct gre_base_hdr *)skb_transport_header(skb);
- pcsum = (__be32 *)(greh + 1);
+ pcsum = (__sum16 *)(greh + 1);
+
+ if (skb_is_gso(skb)) {
+ unsigned int partial_adj;
+
+ /* Adjust checksum to account for the fact that
+ * the partial checksum is based on actual size
+ * whereas headers should be based on MSS size.
+ */
+ partial_adj = skb->len + skb_headroom(skb) -
+ SKB_GSO_CB(skb)->data_offset -
+ skb_shinfo(skb)->gso_size;
+ *pcsum = ~csum_fold((__force __wsum)htonl(partial_adj));
+ } else {
+ *pcsum = 0;
+ }
- *pcsum = 0;
- *(__sum16 *)pcsum = gso_make_checksum(skb, 0);
+ *(pcsum + 1) = 0;
+ *pcsum = gso_make_checksum(skb, 0);
} while ((skb = skb->next));
out:
return segs;