Re: [PATCH net v3] net: vrf: Fix ping failed when vrf mtu is set to 0

[David Ahern <dsa@cumulusnetworks.com>]

On 4/7/19 7:04 PM, linmiaohe wrote:
> From: Miaohe Lin <linmiaohe@huawei.com>
> 
> When the mtu of a vrf device is set to 0, it would cause ping
> failed. So I think we should limit vrf mtu in a reasonable range
> to solve this problem. I set dev->min_mtu to IPV6_MIN_MTU, so it
> will works for both ipv4 and ipv6. And if dev->max_mtu still be 0
> can be confusing, so I set dev->max_mtu to ETH_MAX_MTU.
> 
> Here is the reproduce step:
> 
> 1.Config vrf interface and set mtu to 0:
> 3: enp4s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel
> master vrf1 state UP mode DEFAULT group default qlen 1000
>     link/ether 52:54:00:9e:dd:c1 brd ff:ff:ff:ff:ff:ff
> 
> 2.Ping peer:
> 3: enp4s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel
> master vrf1 state UP group default qlen 1000
>     link/ether 52:54:00:9e:dd:c1 brd ff:ff:ff:ff:ff:ff
>     inet 10.0.0.1/16 scope global enp4s0
>        valid_lft forever preferred_lft forever
> connect: Network is unreachable
> 
> 3.Set mtu to default value, ping works:
> PING 10.0.0.2 (10.0.0.2) 56(84) bytes of data.
> 64 bytes from 10.0.0.2: icmp_seq=1 ttl=64 time=1.88 ms
> 
> Fixes: ad49bc6361ca2 ("net: vrf: remove MTU limits for vrf device")
> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
> ---

Reviewed-by: David Ahern <dsahern@gmail.com>