Re: [pve-devel] [PATCH pve-common 0/1] network: tap_plug: fix mtu bugs

["DERUMIER, Alexandre" <Alexandre.DERUMIER@groupe-cyllene.com>]

Any comment about this patch ?

Forum user have tested it, and it's correctly fixing his mtu problem.

Le vendredi 18 février 2022 à 17:25 +0100, Alexandre Derumier a écrit :
> a forum user have reported strange bug with ovs + mtu9000 when 
> switching between 2 ovs bridge with different mtu. (1500 vs 9000)
> https://antiphishing.cetsi.fr/proxy/v3?i=cWdzUmRSM0ZiRHpoUDkxTSw3-
> 90dQgKDkqmWWemZ6js&r=WXNQOUY5VXRSNUlTdlVTThI4PzxOoz24vDyX_lRDxWFQYQjk
> Hq27xgjw3hQLoamBbuCSKIqia8FUio_zgv2Z4g&f=R0pWUVNEaUFuMTBCTlptbqOdxRIa
> EmX54Uku9_K8PFys74qKNMDYadHFvaTbTNhXBQ48X7FG7vbeJb39p0LVEQ&u=https%3A
> //forum.proxmox.com/threads/ovs-problem-with-mtu-9000-on-vms-
> assigned-to-vmbr0.105172/&k=8YLU
> 
> I have found 2 bugs:
> 
> 1) ovsint port mtu need to be set with ""ovs-vsctl set mtu-request"
> 
> (ip link set mtu 9000 don't seem to do nothing on ovs-int port, maybe
> this have change with last ovs version.)
> 
> 
> fresh start of a vm 100 + firewall on ovs with mtu 9000:
> 
> 153: tap100i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 9000
> qdisc pfifo_fast master fwbr100i0 state UNKNOWN group default qlen
> 1000
>     link/ether 62:42:32:cc:a2:24 brd ff:ff:ff:ff:ff:ff
> 154: fwbr100i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
> noqueue state UP group default qlen 1000
>     link/ether 46:f6:b7:95:23:86 brd ff:ff:ff:ff:ff:ff
> 155: fwln100o0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
> noqueue master fwbr100i0 state UNKNOWN group default qlen 1000
> 
> 
> 2) when switching between 2 bridges or ovs with differents mtu, mtu
> are not updated on existing interfaces (veth,tap, fwbr, fwnl)
> 
> 
> vm start : vmbr0 mtu=1500 + firewall
> -----------------------------
> 200: tap100i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500
> qdisc pfifo_fast master fwbr100i0 state UNKNOWN group default qlen
> 1000
>     link/ether 62:42:32:cc:a2:24 brd ff:ff:ff:ff:ff:ff
> 206: fwbr100i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
> noqueue state UP group default qlen 1000
>     link/ether 46:f6:b7:95:23:86 brd ff:ff:ff:ff:ff:ff
> 207: fwpr100p0@fwln100i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500
> qdisc noqueue master vmbr0 state UP group default qlen 1000
>     link/ether 0a:2e:f5:f4:22:e3 brd ff:ff:ff:ff:ff:ff
> 208: fwln100i0@fwpr100p0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500
> qdisc noqueue master fwbr100i0 state UP group default qlen 1000
>     link/ether 96:0e:94:11:c1:45 brd ff:ff:ff:ff:ff:ff
> 
> 
> switch to vmbr1 mtu=9000 + firewall
> --------------------------------------
> 
> 200: tap100i0: <BROADCAST,MULTICAST,PROMISC,UP,LOWER_UP> mtu 1500
> qdisc pfifo_fast master fwbr100i0 state UNKNOWN group default qlen
> 1000
>     link/ether 62:42:32:cc:a2:24 brd ff:ff:ff:ff:ff:ff
> 209: fwbr100i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc
> noqueue state UP group default qlen 1000
>     link/ether 46:f6:b7:95:23:86 brd ff:ff:ff:ff:ff:ff
> 210: fwpr100p0@fwln100i0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000
> qdisc noqueue master vmbr3 state UP group default qlen 1000
>     link/ether 0a:2e:f5:f4:22:e3 brd ff:ff:ff:ff:ff:ff
> 211: fwln100i0@fwpr100p0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000
> qdisc noqueue master fwbr100i0 state UP group default qlen 1000
>     link/ether 96:0e:94:11:c1:45 brd ff:ff:ff:ff:ff:ff
> 
> 
> 
> 
> Alexandre Derumier (1):
>   network: tap_plug: fix mtu
> 
>  src/PVE/Network.pm | 30 ++++++++++++++++++++----------
>  1 file changed, 20 insertions(+), 10 deletions(-)
>