On 3/8/22 7:16 PM, Xiao, Jiguang wrote:

Hi David

To confirm whether my test method is correct, could you please briefly describe your test procedure? 

no formal test. Code analysis (ip6_pkt_discard{,_out} -> ip6_pkt_drop)
shows the counters that should be incrementing and then looking at the
counters on a local server.

FIB Lookup failures should generate a dst with one of these handlers:

static void ip6_rt_init_dst_reject(struct rt6_info *rt, u8 fib6_type)
{
        rt->dst.error = ip6_rt_type_to_error(fib6_type);

        switch (fib6_type) {
        case RTN_BLACKHOLE:
                rt->dst.output = dst_discard_out;
                rt->dst.input = dst_discard;
                break;
        case RTN_PROHIBIT:
                rt->dst.output = ip6_pkt_prohibit_out;
                rt->dst.input = ip6_pkt_prohibit;
                break;
        case RTN_THROW:
        case RTN_UNREACHABLE:
        default:
                rt->dst.output = ip6_pkt_discard_out;
                rt->dst.input = ip6_pkt_discard;
                break;
        }
}

They all drop the packet with a given counter bumped.