* [PATCH net v2] net: vrf: Fix ping failed when vrf mtu is set to 0
@ 2019-04-07 6:46 linmiaohe
2019-04-07 14:30 ` David Ahern
0 siblings, 1 reply; 3+ messages in thread
From: linmiaohe @ 2019-04-07 6:46 UTC (permalink / raw)
To: David Ahern, Shrijeet Mukherjee, davem, netdev, linux-kernel; +Cc: Mingfangsen
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 1280, 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 0xFFFFU.
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>
---
V1->V2:
- fix patch commit message
- adjust to work for ipv6
drivers/net/vrf.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 7c1430ed0244..4d35d37f225a 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -43,6 +43,12 @@
#define FIB_RULE_PREF 1000 /* default preference for FIB rules */
+/* The MTU is really irrelevant for VRF except for odd cases, so limit it
+ * to a reasonable range which both works for IPV4 and IPV6.
+ */
+#define VRF_MIN_MTU 1280 /* same as IPV6_MIN_MTU */
+#define VRF_MAX_MTU 0xFFFFU /* same as IP_MAX_MTU */
+
static unsigned int vrf_net_id;
struct net_vrf {
@@ -1274,8 +1280,8 @@ static void vrf_setup(struct net_device *dev)
/* default to no qdisc; user can add if desired */
dev->priv_flags |= IFF_NO_QUEUE;
- dev->min_mtu = 0;
- dev->max_mtu = 0;
+ dev->min_mtu = VRF_MIN_MTU;
+ dev->max_mtu = VRF_MAX_MTU;
}
static int vrf_validate(struct nlattr *tb[], struct nlattr *data[],
--
2.19.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net v2] net: vrf: Fix ping failed when vrf mtu is set to 0
2019-04-07 6:46 [PATCH net v2] net: vrf: Fix ping failed when vrf mtu is set to 0 linmiaohe
@ 2019-04-07 14:30 ` David Ahern
2019-04-08 1:58 ` linmiaohe
0 siblings, 1 reply; 3+ messages in thread
From: David Ahern @ 2019-04-07 14:30 UTC (permalink / raw)
To: linmiaohe, Shrijeet Mukherjee, davem, netdev, linux-kernel; +Cc: Mingfangsen
On 4/6/19 11:46 PM, linmiaohe wrote:
> diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
> index 7c1430ed0244..4d35d37f225a 100644
> --- a/drivers/net/vrf.c
> +++ b/drivers/net/vrf.c
> @@ -43,6 +43,12 @@
>
> #define FIB_RULE_PREF 1000 /* default preference for FIB rules */
>
> +/* The MTU is really irrelevant for VRF except for odd cases, so limit it
> + * to a reasonable range which both works for IPV4 and IPV6.
> + */
> +#define VRF_MIN_MTU 1280 /* same as IPV6_MIN_MTU */
> +#define VRF_MAX_MTU 0xFFFFU /* same as IP_MAX_MTU */
Since VRF does not care about MTU, there is no reason for VRF specific
macros.
> +
> static unsigned int vrf_net_id;
>
> struct net_vrf {
> @@ -1274,8 +1280,8 @@ static void vrf_setup(struct net_device *dev)
> /* default to no qdisc; user can add if desired */
> dev->priv_flags |= IFF_NO_QUEUE;
>
> - dev->min_mtu = 0;
> - dev->max_mtu = 0;
> + dev->min_mtu = VRF_MIN_MTU;
> + dev->max_mtu = VRF_MAX_MTU;
Set these to IPV6_MIN_MTU and ETH_MAX_MTU and add a comment that 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.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net v2] net: vrf: Fix ping failed when vrf mtu is set to 0
2019-04-07 14:30 ` David Ahern
@ 2019-04-08 1:58 ` linmiaohe
0 siblings, 0 replies; 3+ messages in thread
From: linmiaohe @ 2019-04-08 1:58 UTC (permalink / raw)
To: David Ahern; +Cc: Shrijeet Mukherjee, davem, netdev, linux-kernel, Mingfangsen
On 2019/4/7 22:30, David Ahern wrote:
> On 4/6/19 11:46 PM, linmiaohe wrote:
>> diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
>> index 7c1430ed0244..4d35d37f225a 100644
>> --- a/drivers/net/vrf.c
>> +++ b/drivers/net/vrf.c
>> @@ -43,6 +43,12 @@
>>
>> #define FIB_RULE_PREF 1000 /* default preference for FIB rules */
>>
>> +/* The MTU is really irrelevant for VRF except for odd cases, so limit it
>> + * to a reasonable range which both works for IPV4 and IPV6.
>> + */
>> +#define VRF_MIN_MTU 1280 /* same as IPV6_MIN_MTU */
>> +#define VRF_MAX_MTU 0xFFFFU /* same as IP_MAX_MTU */
>
> Since VRF does not care about MTU, there is no reason for VRF specific
> macros.
>
>> +
>> static unsigned int vrf_net_id;
>>
>> struct net_vrf {
>> @@ -1274,8 +1280,8 @@ static void vrf_setup(struct net_device *dev)
>> /* default to no qdisc; user can add if desired */
>> dev->priv_flags |= IFF_NO_QUEUE;
>>
>> - dev->min_mtu = 0;
>> - dev->max_mtu = 0;
>> + dev->min_mtu = VRF_MIN_MTU;
>> + dev->max_mtu = VRF_MAX_MTU;
>
> Set these to IPV6_MIN_MTU and ETH_MAX_MTU and add a comment that 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.
>
>
Thanks a lot for your advice. I will send v3 latter.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-04-07 6:46 [PATCH net v2] net: vrf: Fix ping failed when vrf mtu is set to 0 linmiaohe
2019-04-07 14:30 ` David Ahern
2019-04-08 1:58 ` linmiaohe
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