Re: kern/57049: large TCP transfers NetBSD-Xen-Guest -> NetBSD-Xen-DOM0 abort with EHOSTDOWN

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, Oct 07, 2022 at 11:55:00AM +0000, kardel%netbsd.org@localhost wrote:
> >Description:
> 	When copying large files (e.g. 20GB) via scp from a Xen guest to a Xen DOM0 the transfers often fail with EHOSTDOWN.
> 	The errorcode comes from sys/net/nd.c:nd_resolve() (nd.c:384)
> 	The error can be replicated with a simple ttcp test - see below:
> 	Also, during the transfer, following routing messages can be observed on the guest:
> got message of size 152 on Fri Oct  7 11:41:36 2022
> RTM_MISS: Lookup failed on this address: len 152, pid 0, seq 0, errno 0, flags: 0x40<DONE>
> locks: 0 inits: 0
> sockaddrs: 0x3<DST,GATEWAY>
>  10.0.2.16 link#1
> got message of size 152 on Fri Oct  7 11:41:39 2022
> RTM_MISS: Lookup failed on this address: len 152, pid 0, seq 0, errno 0, flags: 0x40<DONE>
> locks: 0 inits: 0
> sockaddrs: 0x3<DST,GATEWAY>
>  10.0.2.16 link#1
> got message of size 152 on Fri Oct  7 11:41:39 2022
> RTM_ADD: Add Route: len 152, pid 0, seq 0, errno 0, flags: 0x2445<UP,HOST,DONE,LLINFO,CLONED>
> locks: 0 inits: 0
> sockaddrs: 0x3<DST,GATEWAY>
>  10.0.2.16 aa:bb:cc:dd:ee:ff
> 
> >How-To-Repeat:
> 	on DOM0:
> 	Zugspitze# ttcp -s -r
> 	ttcp-r: buflen=8192, nbuf=2048, align=16384/0, port=5001  tcp
> 	ttcp-r: socket
> 
> 	on guest:
> 	Guest# ttcp -s -t -n 1000000 zugspitze
> 	ttcp-t: socket
> 	ttcp-t: connect
> 	ttcp-t: IO: Host is down
> 	errno=64

I can't reproduce this (-HEAD dom0, 9.3 domU):
proto:/home/bouyer>./ttcp -s -t -n 1000000 borneo
ttcp-t: buflen=8192, nbuf=1000000, align=16384/0, port=5001  tcp  -> borneo
ttcp-t: socket
ttcp-t: connect
ttcp-t: 8192000000 bytes in 162.54 real seconds = 49218.69 KB/sec +++
ttcp-t: 1000000 I/O calls, msec/call = 0.17, calls/sec = 6152.34
ttcp-t: 3.0user 80.2sys 2:42real 51% 0i+0d 778maxrss 0+2pf 297382+270931csw

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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