Re: kern/57155: OpenVPN (tap and tun) doesn't run as expected on 10.0_BETA

[BERTRAND Joël <joel.bertrand%systella.fr@localhost>]

BERTRAND Joël a écrit :
> The following reply was made to PR kern/57155; it has been noted by GNATS.
> 
> From: =?UTF-8?Q?BERTRAND_Jo=c3=abl?= <joel.bertrand%systella.fr@localhost>
> To: gnats-bugs%netbsd.org@localhost, kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
>         netbsd-bugs%netbsd.org@localhost
> Cc: 
> Subject: Re: kern/57155: OpenVPN (tap and tun) doesn't run as expected on
>  10.0_BETA
> Date: Fri, 6 Jan 2023 11:08:10 +0100
> 
>  Ryota Ozaki a écrit :
>  >  Thanks!
>  
>  	You're welcome.
>  
>  >  The fix has been requested to pull up to the netbsd-10 branch. It will
>  >  be merged soon.
>  >  
>  >  BTW the investigation of the issue of tun would take a little time as
>  >  I'm not successful
>  >  in reproducing the issue.
>  
>  	Strange. In my configuration, tun and tap trigger the same issue...

	I have a simple configuration that triggers this issue with tun interface.

Server : NetBSD 10.0 BETA
openvpn --dev tun1 --ifconfig 10.4.0.1 10.4.0.2 --verb 1

Client (KVM guest that runs on a Linux workstation)
openvpn --remote 192.168.10.128 -dev tun1 --ifconfig 10.4.0.2 10.4.0.1
--verb 1 --float

netbsd-test1# ping 10.4.0.1
PING 10.4.0.1 (10.4.0.1): 56 data bytes
^C
----10.4.0.1 PING Statistics----
167 packets transmitted, 0 packets received, 100.0% packet loss

	On both sides, tun1 are up:

tun1: flags=0x8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
        status: active
        inet6 fe80::a8c4:9abe:2575:9256%tun1/64 ->  flags 0 scopeid 0x3
        inet 10.4.0.2/32 -> 10.4.0.1 flags 0

tun1: flags=0x8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
        status: active
        inet6 fe80::b696:91ff:fe92:776e%tun1/64 ->  flags 0 scopeid 0xb
        inet 10.4.0.1/32 -> 10.4.0.2 flags 0

	tcpdump doesn't show packet over tun1 interfaces and ping from server
returns:
legendre# ping 10.4.0.2
PING 10.4.0.2 (10.4.0.2): 56 data bytes
ping: sendto: Network is unreachable
ping: sendto: Network is unreachable
ping: sendto: Network is unreachable
ping: sendto: Network is unreachable

	Route shows a direct route between server and client:

Internet:
Destination        Gateway            Flags    Refs      Use    Mtu
Interface
default            192.168.15.20      UGS         -        -      -  wm2
10.4.0.1           tun1               UHl         -        -      -  lo0
10.4.0.2           10.4.0.1           UH          -        -      -  tun1

	Why is 10.4.0.2 unreachable ?

	When I did this tests, my VM paniced:

netbsd-test1# tcpdump -i tun1
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on tun1, link-type NULL (BSD loopback), capture size 262144 bytes
09:37:36.390979 IP3
[ 45267.1600841] panic: /: bad dir ino 710294 at offset 0: null entry

[ 45267.1862048] cpu0: Begin traceback...
[ 45267.2093217] vpanic() at netbsd:vpanic+0x183
[ 45267.2093217] panic() at netbsd:panic+0x3c
[ 45267.2211092] ufs_lookup() at netbsd:ufs_lookup+0x483
[ 45267.2559776] VOP_LOOKUP() at netbsd:VOP_LOOKUP+0x44
[ 45267.2700992] lookup_once() at netbsd:lookup_once+0x1a6
[ 45267.3000843] namei_tryemulroot() at netbsd:namei_tryemulroot+0xb00
[ 45267.3261770] namei() at netbsd:namei+0x29
[ 45267.3301437] do_sys_statat() at netbsd:do_sys_statat+0x1db
[ 45267.3301437] sys___lstat50() at netbsd:sys___lstat50+0x25
[ 45267.3301437] syscall() at netbsd:syscall+0x196
[ 45267.3414466] --- syscall (number 441) ---
[ 45267.3414466] netbsd:syscall+0x196:
[ 45267.3414466] cpu0: End traceback...

[ 45267.3972324] dumping to dev 168,2 (offset=1983, size=260872):
[ 45267.3972324] dump 351 350 349 348 347 346 345 344 343 342 341 340
339 338 337 336 335 334 333 332 331 330 329 328 327 326 325 324

	I will try to obtain more information about this panic. This VM has
slow disks as disks images are located on a NAS exported by NFSv3/TCP.

	Best regards,

	JKB