[ovs-discuss] first ip fragment packet doesn't match the L4 field

[Ben Pfaff]

On Sun, Nov 08, 2015 at 11:54:43PM +0800, Huanle Han wrote:
> Hi,
> When I look into the function 'rule_dpif_lookup_from_table', I find it set
> 0 to tp_src and tp_dst for the ip fragment flow, before looking up the rule
> in table.
> It make sense for the later fragments because they have no L4 information.
> But why do it for the first fragment ?

OpenFlow requires it.  See Figure 3 in the OpenFlow 1.0.0 specification.