Drivers: net: hyperv: Address UDP checksum issues

[pandora-kernel.git] / drivers / net / hyperv / netvsc_drv.c

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 6f39baa..31e55fb 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -398,7 +398,30 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
                csum_info->transmit.tcp_checksum = 1;
                csum_info->transmit.tcp_header_offset = hdr_offset;
        } else if (net_trans_info & INFO_UDP) {
-               csum_info->transmit.udp_checksum = 1;
+               /* UDP checksum offload is not supported on ws2008r2.
+                * Furthermore, on ws2012 and ws2012r2, there are some
+                * issues with udp checksum offload from Linux guests.
+                * (these are host issues).
+                * For now compute the checksum here.
+                */
+               struct udphdr *uh;
+               u16 udp_len;
+
+               ret = skb_cow_head(skb, 0);
+               if (ret)
+                       goto drop;
+
+               uh = udp_hdr(skb);
+               udp_len = ntohs(uh->len);
+               uh->check = 0;
+               uh->check = csum_tcpudp_magic(ip_hdr(skb)->saddr,
+                                             ip_hdr(skb)->daddr,
+                                             udp_len, IPPROTO_UDP,
+                                             csum_partial(uh, udp_len, 0));
+               if (uh->check == 0)
+                       uh->check = CSUM_MANGLED_0;
+
+               csum_info->transmit.udp_checksum = 0;
        }
        goto do_send;
 
@@ -438,6 +461,7 @@ do_send:
 
        ret = netvsc_send(net_device_ctx->device_ctx, packet);
 
+drop:
        if (ret == 0) {
                net->stats.tx_bytes += skb->len;
                net->stats.tx_packets++;