vlib_buffer_advance (b0, sizeof (*ip40));
ip_set (&src0, &ip40->src_address, true);
ip_set (&dst0, &ip40->dst_address, true);
vlib_buffer_advance (b0, sizeof (*ip40));
ip_set (&src0, &ip40->src_address, true);
ip_set (&dst0, &ip40->dst_address, true);