4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Haiyang Zhang haiyangz@microsoft.com
[ Upstream commit bf48648d650db1146b75b9bd358502431e86cf4f ]
Incoming packets may have IP header checksum verified by the host. They may not have IP header checksum computed after coalescing. This patch re-compute the checksum when necessary, otherwise the packets may be dropped, because Linux network stack always checks it.
Signed-off-by: Haiyang Zhang haiyangz@microsoft.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/hyperv/netvsc_drv.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-)
--- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -741,6 +741,14 @@ void netvsc_linkstatus_callback(struct h schedule_delayed_work(&ndev_ctx->dwork, 0); }
+static void netvsc_comp_ipcsum(struct sk_buff *skb) +{ + struct iphdr *iph = (struct iphdr *)skb->data; + + iph->check = 0; + iph->check = ip_fast_csum(iph, iph->ihl); +} + static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net, struct napi_struct *napi, const struct ndis_tcp_ip_checksum_info *csum_info, @@ -764,9 +772,17 @@ static struct sk_buff *netvsc_alloc_recv /* skb is already created with CHECKSUM_NONE */ skb_checksum_none_assert(skb);
- /* - * In Linux, the IP checksum is always checked. - * Do L4 checksum offload if enabled and present. + /* Incoming packets may have IP header checksum verified by the host. + * They may not have IP header checksum computed after coalescing. + * We compute it here if the flags are set, because on Linux, the IP + * checksum is always checked. + */ + if (csum_info && csum_info->receive.ip_checksum_value_invalid && + csum_info->receive.ip_checksum_succeeded && + skb->protocol == htons(ETH_P_IP)) + netvsc_comp_ipcsum(skb); + + /* Do L4 checksum offload if enabled and present. */ if (csum_info && (net->features & NETIF_F_RXCSUM)) { if (csum_info->receive.tcp_checksum_succeeded ||