[ovs-dev] [PATCH] datapath: Don't drop packets with partial vlan tags.
Jesse Gross
jesse at nicira.com
Tue Nov 15 01:22:58 UTC 2011
On Mon, Nov 14, 2011 at 5:22 PM, Ben Pfaff <blp at nicira.com> wrote:
> In the future it is likely that our vlan support will expand to
> include multiply tagged packets. When this happens, we would
> ideally like for it to be consistent with our current tagging.
>
> Currently, if we receive a packet with a partial VLAN tag we will
> automatically drop it in the kernel, which is unique among the
> protocols we support. The only other reason to drop a packet is
> a memory allocation error. For a doubly tagged packet, we will
> parse the first tag and indicate that another tag was present but
> do not drop if the second tag is incorrect as we do not parse it.
>
> This changes the behavior of the vlan parser to match other protocols
> and also deeper tags by indicating the presence of a broken tag with
> the 802.1Q EtherType but no vlan information. This shifts the policy
> decision to userspace on whether to drop broken tags and allows us to
> uniformly add new levels of tag parsing.
>
> Although additional levels of control are provided to userspace, this
> maintains the current behavior of dropping packets with a broken
> tag when using the NORMAL action because that is the correct behavior
> for an 802.1Q-aware switch. The userspace flow parser actually
> already had the new behavior so this corrects an inconsistency.
>
> Reported-by: Jesse Gross <jesse at nicira.com>
> Signed-off-by: Ben Pfaff <blp at nicira.com>
Thanks:
Acked-by: Jesse Gross <jesse at nicira.com>
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