vlib_buffer_length_in_chain (vm, b0), si0[0],
&last_sw_if_index, &n_packets, &n_bytes);
vnet_buffer (b0)->sw_if_index[VLIB_RX] = si0[0];
vlib_buffer_length_in_chain (vm, b0), si0[0],
&last_sw_if_index, &n_packets, &n_bytes);
vnet_buffer (b0)->sw_if_index[VLIB_RX] = si0[0];