[PATCH 3.14 103/140] Revert "macvlan : fix checksums error when we are in bridge mode"

From: Greg Kroah-Hartman
Date: Thu May 29 2014 - 01:13:56 EST


3.14-stable review patch. If anyone has any objections, please let me know.

------------------

From: Vlad Yasevich <vyasevic@xxxxxxxxxx>

[ Upstream commit f114890cdf84d753f6b41cd0cc44ba51d16313da ]

This reverts commit 12a2856b604476c27d85a5f9a57ae1661fc46019.
The commit above doesn't appear to be necessary any more as the
checksums appear to be correctly computed/validated.

Additionally the above commit breaks kvm configurations where
one VM is using a device that support checksum offload (virtio) and
the other VM does not.
In this case, packets leaving virtio device will have CHECKSUM_PARTIAL
set. The packets is forwarded to a macvtap that has offload features
turned off. Since we use CHECKSUM_UNNECESSARY, the host does does not
update the checksum and thus a bad checksum is passed up to
the guest.

CC: Daniel Lezcano <daniel.lezcano@xxxxxxx>
CC: Patrick McHardy <kaber@xxxxxxxxx>
CC: Andrian Nord <nightnord@xxxxxxxxx>
CC: Eric Dumazet <eric.dumazet@xxxxxxxxx>
CC: Michael S. Tsirkin <mst@xxxxxxxxxx>
CC: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: Vlad Yasevich <vyasevic@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/macvlan.c | 3 ---
1 file changed, 3 deletions(-)

--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -263,11 +263,9 @@ static int macvlan_queue_xmit(struct sk_
const struct macvlan_dev *vlan = netdev_priv(dev);
const struct macvlan_port *port = vlan->port;
const struct macvlan_dev *dest;
- __u8 ip_summed = skb->ip_summed;

if (vlan->mode == MACVLAN_MODE_BRIDGE) {
const struct ethhdr *eth = (void *)skb->data;
- skb->ip_summed = CHECKSUM_UNNECESSARY;

/* send to other bridge ports directly */
if (is_multicast_ether_addr(eth->h_dest)) {
@@ -285,7 +283,6 @@ static int macvlan_queue_xmit(struct sk_
}

xmit_world:
- skb->ip_summed = ip_summed;
skb->dev = vlan->lowerdev;
return dev_queue_xmit(skb);
}


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