On Monday 01 October 2012 22:53:28 Simon Wunderlich wrote:
It is possible that the mac_len is not properly exported because of strange device configuration (this behaviour has been observed when using batman-adv on top of a vlan interface). Therefore it is needed to explicitly recompute it at the very beginning of the rx path.
This is done by appending the recompute function to the skb_share_mac() function, hence the "dirty hack" in the subject. We expect this problem to be fixed in linux 3.8 and above.
Reported-by: Antonio Quartulli ordex@autistici.org Signed-off-by: Simon Wunderlich siwu@hrz.tu-chemnitz.de
this is a rewrite of Antonios patch "batman-adv: recompute mac_len at the beginning of the rx path". It is intended to fix the issue for out-of-kernel releases, without hurting the in-kernel code too much. Obviously, this patch won't go upstream into the kernel.
compat.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/compat.h b/compat.h index 14969e0..dca9685 100644 --- a/compat.h +++ b/compat.h @@ -159,4 +159,19 @@ static inline void eth_hw_addr_random(struct net_device *dev)
#endif /* < KERNEL_VERSION(3, 5, 0) */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3, 8, 0)
+/* hack for not correctly set mac_len. This may happen for some special
- configurations like batman-adv on VLANs.
- This is pretty dirty, but we only use skb_share_check() in main.c right
- before mac_len is checked, and the recomputation shouldn't hurt too
much. + */ +#define skb_share_check(skb, b) \
- skb_share_check(skb, b); \
- if (skb) \
skb_reset_mac_len(skb)+#endif /* < KERNEL_VERSION(3, 8, 0) */
#endif /* _NET_BATMAN_ADV_COMPAT_H_ */
Can we try a more sane solution like
#define skb_share_check(skb, b) \ ({ \ struct sk_buff *_t_skb; \ _t_skb = skb_share_check(skb, b); \ if (_t_skb) \ skb_reset_mac_len(_t_skb); \ _t_skb; \ })
Please test whether this thing really works and compiles. I just wrote it doing something else and never compiled it.
Kind regards, Sven