From: Jiri Benc <jb...@redhat.com>
Date: Thu, 11 Feb 2016 11:41:24 +0100
> On Wed, 10 Feb 2016 16:47:21 +0100, Paolo Abeni wrote:
>> --- a/drivers/net/geneve.c
>> +++ b/drivers/net/geneve.c
>> @@ -1441,7 +1441,8 @@ struct net_device *geneve_dev_create_fb(struct net
>> *net, const char *name,
>> return dev;
>>
>> err = geneve_configure(net, dev, &geneve_remote_unspec,
>> - 0, 0, 0, htons(dst_port), true, 0);
>> + 0, 0, 0, htons(dst_port), true,
>> + GENEVE_F_UDP_ZERO_CSUM6_RX);
>> if (err) {
>> free_netdev(dev);
>> return ERR_PTR(err);
>> diff --git a/net/openvswitch/vport-vxlan.c b/net/openvswitch/vport-vxlan.c
>> index 1605691..d933cb8 100644
>> --- a/net/openvswitch/vport-vxlan.c
>> +++ b/net/openvswitch/vport-vxlan.c
>> @@ -90,7 +90,7 @@ static struct vport *vxlan_tnl_create(const struct
>> vport_parms *parms)
>> int err;
>> struct vxlan_config conf = {
>> .no_share = true,
>> - .flags = VXLAN_F_COLLECT_METADATA,
>> + .flags = VXLAN_F_COLLECT_METADATA | VXLAN_F_UDP_ZERO_CSUM6_RX,
>
> I'm afraid this looks wrong, we should not default to zero UDP checksum
> over IPv6. See RFC 2460, section 8.1:
>
> o Unlike IPv4, when UDP packets are originated by an IPv6 node,
> the UDP checksum is not optional. That is, whenever
> originating a UDP packet, an IPv6 node must compute a UDP
> checksum over the packet and the pseudo-header, and, if that
> computation yields a result of zero, it must be changed to hex
> FFFF for placement in the UDP header. IPv6 receivers must
> discard UDP packets containing a zero checksum, and should log
> the error.
>
> One may argue that with tunneling, the situation is different but
> that's the reason why we have the IPv6 checksum flag and why it has
> opposite meaning to the IPv4 one. We shouldn't default to non-RFC
> behavior by default.
>
> What is the problem with the current code? Is the UDP checksum not
> calculated correctly?
Furthermore, we should be setting the checksum by default for ipv4 too.
It's faster.
