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| author |   Shigeru Yoshida <syoshida@redhat.com> | 2022-08-20 12:25:16 +0900 |
|---|---|---|
| committer |   Simon Wunderlich <sw@simonwunderlich.de> | 2022-08-20 14:17:45 +0200 |
| commit | b1cb8a71f1eaec4eb77051590f7f561f25b15e32 (patch) | |
| tree | 9e1187fbd099df957e94ce567ba5ab9f27b9fc16 | |
| parent | Linux 6.0-rc1 (diff) | |
| download | linux-dev-b1cb8a71f1eaec4eb77051590f7f561f25b15e32.tar.xz linux-dev-b1cb8a71f1eaec4eb77051590f7f561f25b15e32.zip | |
batman-adv: Fix hang up with small MTU hard-interface
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.
Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
| -rw-r--r-- | net/batman-adv/hard-interface.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index b8f8da7ee3de..41c1ad33d009 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -10,6 +10,7 @@ #include <linux/atomic.h> #include <linux/byteorder/generic.h> #include <linux/container_of.h> +#include <linux/errno.h> #include <linux/gfp.h> #include <linux/if.h> #include <linux/if_arp.h> @@ -700,6 +701,9 @@ 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; |