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authorShigeru Yoshida <syoshida@redhat.com>2022-08-20 06:25:16 +0300
committerSimon Wunderlich <sw@simonwunderlich.de>2022-08-20 15:17:45 +0300
commitb1cb8a71f1eaec4eb77051590f7f561f25b15e32 (patch)
tree9e1187fbd099df957e94ce567ba5ab9f27b9fc16 /net/batman-adv
parent568035b01cfb107af8d2e4bd2fb9aea22cf5b868 (diff)
downloadlinux-b1cb8a71f1eaec4eb77051590f7f561f25b15e32.tar.xz
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>
Diffstat (limited to 'net/batman-adv')
-rw-r--r--net/batman-adv/hard-interface.c4
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;