[PATCH net-next v2 0/2] 6lowpan: fragmentation fixes

This patch series fix the 6LoWPAN fragmentation which are in two cases broken.

The first case is if we have exactly two 6LoWPAN fragments only. This is fixed
by patch "6lowpan_rtnl: fix fragmentation with two fragments".
The second case is a off by one issue if we have payload which hits the fragment
boundary.

Both issues are introduced by commit d4b2816d67d6e07b2f27037f282d8db03a5829d7
("6lowpan: fix fragmentation").

Alexander Aring (2):
  6lowpan_rtnl: fix fragmentation with two fragments
  6lowpan_rtnl: fix off by one while fragmentation

 net/ieee802154/6lowpan_rtnl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
1.9.3

This patch fix the 6LoWPAN fragmentation for the case if we have exactly
two fragments. The problem is that the (skb_unprocessed >= frag_cap)
condition is always false on the second fragment after sending the first
fragment. A fragmentation with only one fragment doesn't make any sense.
The solution is that we use a do while loop here, that ensures we sending
always a minimum of two fragments if we need a fragmentation.

This issue was introduced by commit d4b2816d67d6e07b2f27037f282d8db03a5829d7
("6lowpan: fix fragmentation").

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
---
 net/ieee802154/6lowpan_rtnl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ieee802154/6lowpan_rtnl.c b/net/ieee802154/6lowpan_rtnl.c
index 1ae8a56..9d57026 100644
--- a/net/ieee802154/6lowpan_rtnl.c
+++ b/net/ieee802154/6lowpan_rtnl.c

@@ -312,7 +312,7 @@ lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *dev,
 	frag_hdr[0] |= LOWPAN_DISPATCH_FRAGN;
 	frag_cap = round_down(payload_cap - LOWPAN_FRAGN_HEAD_SIZE, 8);
 
-	while (skb_unprocessed >= frag_cap) {
+	do {
 		dgram_offset += frag_len;
 		skb_offset += frag_len;
 		skb_unprocessed -= frag_len;

@@ -328,7 +328,7 @@ lowpan_xmit_fragmented(struct sk_buff *skb, struct net_device *dev,
 				 __func__, frag_tag, skb_offset);
 			goto err;
 		}
-	}
+	} while (skb_unprocessed >= frag_cap);
 
 	consume_skb(skb);
 	return NET_XMIT_SUCCESS;

-- 
1.9.3

From: Alexander Aring <alex.aring@gmail.com>
Date: Mon,  2 Jun 2014 13:21:56 +0200

This patch series fix the 6LoWPAN fragmentation which are in two cases broken.

The first case is if we have exactly two 6LoWPAN fragments only. This is fixed
by patch "6lowpan_rtnl: fix fragmentation with two fragments".
The second case is a off by one issue if we have payload which hits the fragment
boundary.

Both issues are introduced by commit d4b2816d67d6e07b2f27037f282d8db03a5829d7
("6lowpan: fix fragmentation").

Series applied, thanks Alexander.