From: Miaohe Lin <[email protected]>
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 <[email protected]>
---
V2->V3:
- delete VRF specific mtu macros
- set mtu range directly and add a comment
drivers/net/vrf.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 6d1a1abbed27..cd15c32b2e43 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -1275,8 +1275,12 @@ static void vrf_setup(struct net_device *dev)
dev->priv_flags |= IFF_NO_QUEUE;
dev->priv_flags |= IFF_NO_RX_HANDLER;
- dev->min_mtu = 0;
- dev->max_mtu = 0;
+ /* VRF devices do not care about MTU, but if the MTU is set
+ * too low then the ipv4 and ipv6 protocols are disabled
+ * which breaks networking.
+ */
+ dev->min_mtu = IPV6_MIN_MTU;
+ dev->max_mtu = ETH_MAX_MTU;
}
static int vrf_validate(struct nlattr *tb[], struct nlattr *data[],
--
2.19.1
On 4/7/19 7:04 PM, linmiaohe wrote:
> From: Miaohe Lin <[email protected]>
>
> 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 <[email protected]>
> ---
Reviewed-by: David Ahern <[email protected]>
From: David Ahern <[email protected]>
Date: Sun, 7 Apr 2019 20:51:05 -0700
> On 4/7/19 7:04 PM, linmiaohe wrote:
>> From: Miaohe Lin <[email protected]>
>>
>> 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:
...
>> Fixes: ad49bc6361ca2 ("net: vrf: remove MTU limits for vrf device")
>> Signed-off-by: Miaohe Lin <[email protected]>
>> ---
>
> Reviewed-by: David Ahern <[email protected]>
Applied and queued up for -stable, thanks.