net: Add GSO support for UDP tunnels with checksum
Added a new netif feature for GSO_UDP_TUNNEL_CSUM. This indicates
that a device is capable of computing the UDP checksum in the
encapsulating header of a UDP tunnel.
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index a84f676..8d8c33d 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2528,7 +2528,11 @@
int tnl_hlen = skb_inner_mac_header(skb) - skb_transport_header(skb);
__be16 protocol = skb->protocol;
netdev_features_t enc_features;
- int outer_hlen;
+ int udp_offset, outer_hlen;
+ unsigned int oldlen;
+ bool need_csum;
+
+ oldlen = (u16)~skb->len;
if (unlikely(!pskb_may_pull(skb, tnl_hlen)))
goto out;
@@ -2540,6 +2544,10 @@
skb->mac_len = skb_inner_network_offset(skb);
skb->protocol = htons(ETH_P_TEB);
+ need_csum = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM);
+ if (need_csum)
+ skb->encap_hdr_csum = 1;
+
/* segment inner packet. */
enc_features = skb->dev->hw_enc_features & netif_skb_features(skb);
segs = skb_mac_gso_segment(skb, enc_features);
@@ -2550,10 +2558,11 @@
}
outer_hlen = skb_tnl_header_len(skb);
+ udp_offset = outer_hlen - tnl_hlen;
skb = segs;
do {
struct udphdr *uh;
- int udp_offset = outer_hlen - tnl_hlen;
+ int len;
skb_reset_inner_headers(skb);
skb->encapsulation = 1;
@@ -2564,31 +2573,20 @@
skb_reset_mac_header(skb);
skb_set_network_header(skb, mac_len);
skb_set_transport_header(skb, udp_offset);
+ len = skb->len - udp_offset;
uh = udp_hdr(skb);
- uh->len = htons(skb->len - udp_offset);
+ uh->len = htons(len);
- /* csum segment if tunnel sets skb with csum. */
- if (protocol == htons(ETH_P_IP) && unlikely(uh->check)) {
- struct iphdr *iph = ip_hdr(skb);
+ if (need_csum) {
+ __be32 delta = htonl(oldlen + len);
- uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
- skb->len - udp_offset,
- IPPROTO_UDP, 0);
- uh->check = csum_fold(skb_checksum(skb, udp_offset,
- skb->len - udp_offset, 0));
+ uh->check = ~csum_fold((__force __wsum)
+ ((__force u32)uh->check +
+ (__force u32)delta));
+ uh->check = gso_make_checksum(skb, ~uh->check);
+
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
-
- } else if (protocol == htons(ETH_P_IPV6)) {
- struct ipv6hdr *ipv6h = ipv6_hdr(skb);
- u32 len = skb->len - udp_offset;
-
- uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
- len, IPPROTO_UDP, 0);
- uh->check = csum_fold(skb_checksum(skb, udp_offset, len, 0));
- if (uh->check == 0)
- uh->check = CSUM_MANGLED_0;
- skb->ip_summed = CHECKSUM_NONE;
}
skb->protocol = protocol;