15 Sep
2012
15 Sep
'12
12:34 p.m.
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
Signed-off-by: Antonio Quartulli <ordex(a)autistici.org>
---
main.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/main.c b/main.c
index f9bcfa1..4ef39b6 100644
--- a/main.c
+++ b/main.c
@@ -245,6 +245,12 @@ int batadv_batman_skb_recv(struct sk_buff *skb, struct net_device
*dev,
if (unlikely(!pskb_may_pull(skb, 2)))
goto err_free;
+ /* sometimes the mac_len value is not properly computed (e.g. when using
+ * batman-adv on top of a vlan interface), therefore we need to
+ * explicitly recompute it here
+ */
+ skb_reset_mac_len(skb);
+
/* expect a valid ethernet header here. */
if (unlikely(skb->mac_len != ETH_HLEN || !skb_mac_header(skb)))
goto err_free;
--
1.7.12
29 Sep
29 Sep
11:27 a.m.
New subject: [B.A.T.M.A.N.] [PATCH] batman-adv: recompute mac_len at the beginning of the rx path
On Sat, Sep 15, 2012 at 02:34:21 +0200, Antonio Quartulli 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
Signed-off-by: Antonio Quartulli <ordex(a)autistici.org>
Instead of merging this patch I think that the best approach would be to fix the
problem in VLAN code in the kernel.
I'll try to send a patch to netdev.
Cheers,
--
Antonio Quartulli
..each of us alone is worth nothing..
Ernesto "Che" Guevara
1 Oct
1 Oct
8:56 p.m.
New subject: [B.A.T.M.A.N.] [PATCH] batman-adv: recompute mac_len at the beginning of the rx path
Hey Antonio,
although I agree that it is the better way to get the fix in the kernel instead of
batman-adv, it would be good to have a workaround in batman-adv for out-of-tree
versions.
I've just sent a (pretty dirty) suggestion, another idea would be to get patches in
the various distributions (openwrt, debian, gentoo, ...) - which would still leave
the problem open for the next "source" release.
Cheers,
Simon
On Sat, Sep 29, 2012 at 01:27:57PM +0200, Antonio Quartulli wrote:
On Sat, Sep 15, 2012 at 02:34:21 +0200, Antonio
Quartulli 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
Signed-off-by: Antonio Quartulli <ordex(a)autistici.org>
Instead of merging this patch I think that the best approach would be to fix the
problem in VLAN code in the kernel.
I'll try to send a patch to netdev.
Cheers,
--
Antonio Quartulli
..each of us alone is worth nothing..
Ernesto "Che" Guevara
8:53 p.m.
New subject: [B.A.T.M.A.N.] [RFC] batman-adv: dirty hack to recompute mac_len in the rx path
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(a)autistici.org>
Signed-off-by: Simon Wunderlich <siwu(a)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_ */
--
1.7.10
2 Oct
2 Oct
5:16 a.m.
New subject: [B.A.T.M.A.N.] [RFC] batman-adv: dirty hack to recompute mac_len in the rx path
On Tuesday, October 02, 2012 04:53:28 Simon Wunderlich wrote:
+#define skb_share_check(skb, b) \
+ skb_share_check(skb, b); \
+ if (skb) \
+ skb_reset_mac_len(skb)
+
+#endif /* < KERNEL_VERSION(3, 8, 0) */
Has this patch been tested ? Our skb_share_check() call is this:
skb = skb_share_check(skb, GFP_ATOMIC);
Now we replace this function call with 2 function calls and 2 return values ?
Cheers,
Marek
9:37 a.m.
New subject: [B.A.T.M.A.N.] [RFC] batman-adv: dirty hack to recompute mac_len in the rx path
Hello Marek,
On Tue, Oct 02, 2012 at 01:16:40PM +0800, Marek Lindner wrote:
On Tuesday, October 02, 2012 04:53:28 Simon Wunderlich
wrote:
I have not tested in a real machine, but only the first function will
return the skb. The second part is a separate statement. I've checked
it with gcc -E (preprocessor only), these lines in main.c will expand to:
hard_iface = ({ const typeof( ((struct batadv_hard_iface *)0)->batman_adv_ptype )
*__mptr = (ptype); (struct batadv_hard_iface *)( (char *)__mptr -
__builtin_offsetof(struct batadv_hard_iface,batman_adv_ptype) );})
;
skb = skb_share_check(skb, ((( gfp_t)0x20u))); if (skb) skb_reset_mac_len(skb);
if (!skb)
goto err_out;
As you can see, the skb = skb_share_check() statement stays at it is, and
the reset_mac_len() is done afterwards.
Cheers,
Simon
+#define skb_share_check(skb, b) \
+ skb_share_check(skb, b); \
+ if (skb) \
+ skb_reset_mac_len(skb)
+
+#endif /* < KERNEL_VERSION(3, 8, 0) */
Has this patch been tested ? Our skb_share_check() call is this:
skb = skb_share_check(skb, GFP_ATOMIC);
Now we replace this function call with 2 function calls and 2 return values ? 
6 Oct
6 Oct
4:45 p.m.
New subject: [B.A.T.M.A.N.] [RFC] batman-adv: dirty hack to recompute mac_len in the rx path
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(a)autistici.org>
Signed-off-by: Simon Wunderlich <siwu(a)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
14 Oct
14 Oct
12:46 p.m.
New subject: [B.A.T.M.A.N.] [PATCH] batman-adv: dirty hack to recompute mac_len in the rx path
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(a)autistici.org>
Signed-off-by: Simon Wunderlich <siwu(a)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.
This version includes Svens "more sane" version, and also has implements
skb_reset_mac_len() for kernels prior to 3.0.
---
compat.h | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/compat.h b/compat.h
index 14969e0..47223f5 100644
--- a/compat.h
+++ b/compat.h
@@ -137,6 +137,11 @@ void batadv_free_rcu_neigh_node(struct rcu_head *rcu);
void batadv_free_rcu_tt_local_entry(struct rcu_head *rcu);
void batadv_free_rcu_backbone_gw(struct rcu_head *rcu);
+static inline void skb_reset_mac_len(struct sk_buff *skb)
+{
+ skb->mac_len = skb->network_header - skb->mac_header;
+}
+
#endif /* < KERNEL_VERSION(3, 0, 0) */
@@ -159,4 +164,23 @@ 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) \
+ ({ \
+ struct sk_buff *_t_skb; \
+ _t_skb = skb_share_check(skb, b); \
+ if (_t_skb) \
+ skb_reset_mac_len(_t_skb); \
+ _t_skb; \
+ })
+
+#endif /* < KERNEL_VERSION(3, 8, 0) */
+
#endif /* _NET_BATMAN_ADV_COMPAT_H_ */
--
1.7.10
6:53 p.m.
New subject: [B.A.T.M.A.N.] [PATCH] batman-adv: dirty hack to recompute mac_len in the rx path
On Sunday, October 14, 2012 20:46:57 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(a)autistici.org>
Signed-off-by: Simon Wunderlich <siwu(a)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.
This version includes Svens "more sane" version, and also has implements
skb_reset_mac_len() for kernels prior to 3.0.
---
compat.h | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
Applied in revision a6ad857.
Thanks,
Marek
3819
days inactive
3848
days old
b.a.t.m.a.n@lists.open-mesh.org
8 comments
4 participants
participants (4)
-
Antonio Quartulli -
Marek Lindner -
Simon Wunderlich -
Sven Eckelmann