# Re: \[PATCH net-next\] neigh: increase queue\_len\_bytes to match wmem\_default

- From: David Miller \<davem@davemloft.net\>
- Date: 2017-08-29 23:11:06 
- List: netdev
- Page: https://ratatoskr.run/netdev/2017/08/11064670
- Thread: https://ratatoskr.run/netdev/2017/08/11063890/t.md

```text
From: Eric Dumazet <redacted>
Date: Tue, 29 Aug 2017 15:16:01 -0700

> From: Eric Dumazet <redacted>
> 
> Florian reported UDP xmit drops that could be root caused to the
> too small neigh limit.
> 
> Current limit is 64 KB, meaning that even a single UDP socket would hit
> it, since its default sk_sndbuf comes from net.core.wmem_default
> (~212992 bytes on 64bit arches).
> 
> Once ARP/ND resolution is in progress, we should allow a little more
> packets to be queued, at least for one producer.
> 
> Once neigh arp_queue is filled, a rogue socket should hit its sk_sndbuf
> limit and either block in sendmsg() or return -EAGAIN.
> 
> Signed-off-by: Eric Dumazet <redacted>
> Reported-by: Florian Fainelli <f.fainelli@gmail.com>

Applied, thanks for following up on this.
```