On Thu, Apr 18, 2024 at 11:33 AM Paolo Abeni <pabeni@xxxxxxxxxx> wrote: > > On Tue, 2024-04-16 at 10:36 +0000, Li, James Zheng wrote: > > On Tuesday, April 16, 2024 6:02 PM Eric Dumazet <edumazet@xxxxxxxxxx> wrote: > > > Hmmm... > > > > > Loopback IPv4 can hold 2^24 different addresses, that is 16384 * 1024 > > > > There is only one Loopback neigh "0.0.0.0 dev lo lladdr 00:00:00:00:00:00 NOARP" > > existing even you have configured 2^24 different addresses on the loopback device. > > Eric, I think James is right, in __ipv4_neigh_lookup_noref(): > > if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) > key = INADDR_ANY; > > return ___neigh_lookup_noref(&arp_tbl, neigh_key_eq32, arp_hashfn, &key, dev); > > So there should be at most one neigh entry over the loopback device. > The patch looks safe to me, am I missing something? This seems fine, thanks. It is unfortunate ip command does not seem to display these neighbours, for some reason. (I am about to send a series of three patches to remove RTNL from "ip neighbour show") Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
