Commit e52fed71 authored by Stephen Hemminger's avatar Stephen Hemminger Committed by David S. Miller

netvsc: fix incorrect receive checksum offloading

The Hyper-V netvsc driver was looking at the incorrect status bits
in the checksum info. It was setting the receive checksum unnecessary
flag based on the IP header checksum being correct. The checksum
flag is skb is about TCP and UDP checksum status. Because of this
bug, any packet received with bad TCP checksum would be passed
up the stack and to the application causing data corruption.
The problem is reproducible via netcat and netem.

This had a side effect of not doing receive checksum offload
on IPv6. The driver was also also always doing checksum offload
independent of the checksum setting done via ethtool.
Signed-off-by: default avatarStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 10df8e61
...@@ -607,15 +607,18 @@ static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net, ...@@ -607,15 +607,18 @@ static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net,
packet->total_data_buflen); packet->total_data_buflen);
skb->protocol = eth_type_trans(skb, net); skb->protocol = eth_type_trans(skb, net);
if (csum_info) {
/* We only look at the IP checksum here. /* skb is already created with CHECKSUM_NONE */
* Should we be dropping the packet if checksum skb_checksum_none_assert(skb);
* failed? How do we deal with other checksums - TCP/UDP?
/*
* In Linux, the IP checksum is always checked.
* Do L4 checksum offload if enabled and present.
*/ */
if (csum_info->receive.ip_checksum_succeeded) if (csum_info && (net->features & NETIF_F_RXCSUM)) {
if (csum_info->receive.tcp_checksum_succeeded ||
csum_info->receive.udp_checksum_succeeded)
skb->ip_summed = CHECKSUM_UNNECESSARY; skb->ip_summed = CHECKSUM_UNNECESSARY;
else
skb->ip_summed = CHECKSUM_NONE;
} }
if (vlan_tci & VLAN_TAG_PRESENT) if (vlan_tci & VLAN_TAG_PRESENT)
......
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