[PATCH] 6lowpan: consider checksum bytes in fragmentation threshold

[PATCH] 6lowpan: consider checksum bytes in fragmentation threshold

[Alan Ott]

Change the threshold for framentation of a lowpan packet from
using the MTU size to now use the MTU size minus the checksum length,
which is added by the hardware. For IEEE 802.15.4, this effectively
changes it from 127 bytes to 125 bytes.

Signed-off-by: Alan Ott <alan@signal11.us>
---
 net/ieee802154/6lowpan.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ieee802154/6lowpan.c b/net/ieee802154/6lowpan.c
index 6d42c17..f651da6 100644
--- a/net/ieee802154/6lowpan.c
+++ b/net/ieee802154/6lowpan.c
@@ -1047,7 +1047,8 @@ static netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev)
 		goto error;
 	}
 
-	if (skb->len <= IEEE802154_MTU) {
+	/* Send directly if less than the MTU minus the 2 checksum bytes. */
+	if (skb->len <= IEEE802154_MTU - IEEE802154_MFR_SIZE) {
 		err = dev_queue_xmit(skb);
 		goto out;
 	}
-- 
1.7.11.2

Re: [PATCH] 6lowpan: consider checksum bytes in fragmentation threshold

[Alan Ott]

On 11/29/2012 08:55 PM, Alan Ott wrote:
> Change the threshold for framentation of a lowpan packet from
> using the MTU size to now use the MTU size minus the checksum length,
> which is added by the hardware. For IEEE 802.15.4, this effectively
> changes it from 127 bytes to 125 bytes.
>

Sorry, this was put in the wrong thread. One day I'll get one of these
first-try. :(

[PATCH 1/2] mac802154: fix memory leaks

[Alan Ott]

kfree_skb() was not getting called in the case of some failures.
This was pointed out by Eric Dumazet.

Signed-off-by: Alan Ott <alan@signal11.us>
---
 net/mac802154/tx.c   | 5 ++++-
 net/mac802154/wpan.c | 4 +++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
index 1a4df39..db63914 100644
--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c
@@ -85,6 +85,7 @@ netdev_tx_t mac802154_tx(struct mac802154_priv *priv, struct sk_buff *skb,
 
 	if (!(priv->phy->channels_supported[page] & (1 << chan))) {
 		WARN_ON(1);
+		kfree_skb(skb);
 		return NETDEV_TX_OK;
 	}
 
@@ -103,8 +104,10 @@ netdev_tx_t mac802154_tx(struct mac802154_priv *priv, struct sk_buff *skb,
 	}
 
 	work = kzalloc(sizeof(struct xmit_work), GFP_ATOMIC);
-	if (!work)
+	if (!work) {
+		kfree_skb(skb);
 		return NETDEV_TX_BUSY;
+	}
 
 	INIT_WORK(&work->work, mac802154_xmit_worker);
 	work->skb = skb;
diff --git a/net/mac802154/wpan.c b/net/mac802154/wpan.c
index f30f6d4..1191039 100644
--- a/net/mac802154/wpan.c
+++ b/net/mac802154/wpan.c
@@ -327,8 +327,10 @@ mac802154_wpan_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	if (chan == MAC802154_CHAN_NONE ||
 	    page >= WPAN_NUM_PAGES ||
-	    chan >= WPAN_NUM_CHANNELS)
+	    chan >= WPAN_NUM_CHANNELS) {
+		kfree_skb(skb);
 		return NETDEV_TX_OK;
+	}
 
 	skb->skb_iif = dev->ifindex;
 	dev->stats.tx_packets++;
-- 
1.7.11.2

[PATCH 2/2] mac802154: use kfree_skb() instead of dev_kfree_skb()

[Alan Ott]

kfree_skb() indicates failure, which is where this is being used.

Signed-off-by: Alan Ott <alan@signal11.us>
---
 net/mac802154/tx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac802154/tx.c b/net/mac802154/tx.c
index db63914..4e09d07 100644
--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c
@@ -99,7 +99,7 @@ netdev_tx_t mac802154_tx(struct mac802154_priv *priv, struct sk_buff *skb,
 	}
 
 	if (skb_cow_head(skb, priv->hw.extra_tx_headroom)) {
-		dev_kfree_skb(skb);
+		kfree_skb(skb);
 		return NETDEV_TX_OK;
 	}
 
-- 
1.7.11.2

Re: [PATCH] 6lowpan: consider checksum bytes in fragmentation threshold

[David Miller]

From: Alan Ott <alan@signal11.us>
Date: Thu, 29 Nov 2012 20:55:44 -0500

> Change the threshold for framentation of a lowpan packet from
> using the MTU size to now use the MTU size minus the checksum length,
> which is added by the hardware. For IEEE 802.15.4, this effectively
> changes it from 127 bytes to 125 bytes.
> 
> Signed-off-by: Alan Ott <alan@signal11.us>

Applied.

Re: [PATCH 1/2] mac802154: fix memory leaks

[David Miller]

From: Alan Ott <alan@signal11.us>
Date: Thu, 29 Nov 2012 23:25:10 -0500

> kfree_skb() was not getting called in the case of some failures.
> This was pointed out by Eric Dumazet.
> 
> Signed-off-by: Alan Ott <alan@signal11.us>

Applied.

Re: [PATCH 2/2] mac802154: use kfree_skb() instead of dev_kfree_skb()

[David Miller]

From: Alan Ott <alan@signal11.us>
Date: Thu, 29 Nov 2012 23:25:11 -0500

> kfree_skb() indicates failure, which is where this is being used.
> 
> Signed-off-by: Alan Ott <alan@signal11.us>

Applied.