[ovs-dev] [PATCH v3 3/6] ovn: Add a new OVN field icmp4.frag_mtu

Ben Pfaff blp at ovn.org
Thu Apr 18 21:55:58 UTC 2019


On Tue, Apr 16, 2019 at 01:23:56PM +0530, nusiddiq at redhat.com wrote:
> From: Numan Siddique <nusiddiq at redhat.com>
> 
> In order to support OVN specific fields (which are not yet
> supported in OpenvSwitch to set or modify values) a generic
> OVN field support is added in this patch. These OVN fields
> gets translated to controller actions.
> 
> This patch adds only one field for now - icmp4.frag_mtu.
> It should be fairly straightforward to add similar fields in the
> near future.

Thanks for the patch!

I don't see documentation for the new field icmp4.frag_mtu.  I guess
that it should go in ovn/ovn-sb.xml near the other documentation for
fields.

This calculation in pinctrl_handle_icmp() looks suspect to me.  Does it
function properly if the packet is larger than about 576 bytes and the
subtraction wraps around?

+            /* Calculate available room to include the original IP + data. */
+            nh = dp_packet_l3(&packet);
+            uint16_t room = 576 - (sizeof *eh + ntohs(nh->ip_tot_len));
+            if (in_ip_len > room) {
+                in_ip_len = room;
+            }

Thanks,

Ben.


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