The system hangs up when batman-adv soft-interface is created on
hard-interface with small MTU. For example, the following commands
create batman-adv soft-interface on dummy interface with zero MTU:
# ip link add name dummy0 type dummy
# ip link set mtu 0 dev dummy0
# ip link set up dev dummy0
# ip link add name bat0 type batadv
# ip link set dev dummy0 master bat0
These commands cause the system hang up with the following messages:
[ 90.578925][ T6689] batman_adv: bat0: Adding interface: dummy0
[ 90.580884][ T6689] batman_adv: bat0: The MTU of interface dummy0 is too small (0) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem.
[ 90.586264][ T6689] batman_adv: bat0: Interface activated: dummy0
[ 90.590061][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320)
[ 90.595517][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320)
[ 90.598499][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320)
This patch fixes this issue by returning error when enabling
hard-interface with small MTU size.
Signed-off-by: Shigeru Yoshida <[email protected]>
---
net/batman-adv/hard-interface.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index b8f8da7ee3de..dce5557800e9 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -700,6 +700,9 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
int max_header_len = batadv_max_header_len();
int ret;
+ if (hard_iface->net_dev->mtu < ETH_MIN_MTU + max_header_len)
+ return -EINVAL;
+
if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
goto out;
--
2.37.2
ping?
On Sat, 20 Aug 2022 12:25:16 +0900, Shigeru Yoshida wrote:
> The system hangs up when batman-adv soft-interface is created on
> hard-interface with small MTU. For example, the following commands
> create batman-adv soft-interface on dummy interface with zero MTU:
>
> # ip link add name dummy0 type dummy
> # ip link set mtu 0 dev dummy0
> # ip link set up dev dummy0
> # ip link add name bat0 type batadv
> # ip link set dev dummy0 master bat0
>
> These commands cause the system hang up with the following messages:
>
> [ 90.578925][ T6689] batman_adv: bat0: Adding interface: dummy0
> [ 90.580884][ T6689] batman_adv: bat0: The MTU of interface dummy0 is too small (0) to handle the transport of batman-adv packets. Packets going over this interface will be fragmented on layer2 which could impact the performance. Setting the MTU to 1560 would solve the problem.
> [ 90.586264][ T6689] batman_adv: bat0: Interface activated: dummy0
> [ 90.590061][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320)
> [ 90.595517][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320)
> [ 90.598499][ T6689] batman_adv: bat0: Forced to purge local tt entries to fit new maximum fragment MTU (-320)
>
> This patch fixes this issue by returning error when enabling
> hard-interface with small MTU size.
>
> Signed-off-by: Shigeru Yoshida <[email protected]>
> ---
> net/batman-adv/hard-interface.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
> index b8f8da7ee3de..dce5557800e9 100644
> --- a/net/batman-adv/hard-interface.c
> +++ b/net/batman-adv/hard-interface.c
> @@ -700,6 +700,9 @@ int batadv_hardif_enable_interface(struct batadv_hard_iface *hard_iface,
> int max_header_len = batadv_max_header_len();
> int ret;
>
> + if (hard_iface->net_dev->mtu < ETH_MIN_MTU + max_header_len)
> + return -EINVAL;
> +
> if (hard_iface->if_status != BATADV_IF_NOT_IN_USE)
> goto out;
>
> --
> 2.37.2
>
On Wednesday, 7 September 2022 18:00:37 CEST Shigeru Yoshida wrote:
> ping?
This was applied a while ago:
https://git.open-mesh.org/linux-merge.git/commit/b1cb8a71f1eaec4eb77051590f7f561f25b15e32
Kind regards,
Sven
Hi Sven,
On Wed, 07 Sep 2022 18:04:09 +0200,Wed, 07 Sep 2022 18:04:09 +0200, Sven Eckelmann wrote:
> On Wednesday, 7 September 2022 18:00:37 CEST Shigeru Yoshida wrote:
>> ping?
>
> This was applied a while ago:
>
> https://git.open-mesh.org/linux-merge.git/commit/b1cb8a71f1eaec4eb77051590f7f561f25b15e32
Sorry, I didn't notice that. Thank you so much!!
Thanks,
Shigeru
>
> Kind regards,
> Sven