Re: [PATCH] neighbour: guarantee the localhost connections be established successfully even the ARP table is full

[Paolo Abeni <pabeni@xxxxxxxxxx>]

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?

Thanks,

Paolo