On 6/23/20 11:38 AM, Ido Schimmel wrote: >> >> My questions are: >> 1. is fib_lookup supposed to work with multicast daddr? If so, has >> multicast routing been working for the wrong reason?
yes; it is a quirk with Linux routing. see the code after fib_lookup in ip_route_output_key_hash_rcu. perf can show you the call chain that gets to that lookup if you want the details. >> 2. Why does the addition of a unicast default route affect multicast >> routing behaviour? > > I believe this was discussed in the past. See: > https://lore.kernel.org/netdev/20200115191920.GA1490933@splinter/#t >
