[PATCH RFC] xfrm: Don't queue retransmitted packets if the original is still on the host

[Steffen Klassert <steffen.klassert@secunet.com>]

It does not make sense to queue retransmitted packets if the
original packet is still in some queue of this host. So add
a check to xdst_queue_output() and drop the packet if the
original packet is not yet sent.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/xfrm/xfrm_policy.c |    7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index ed38d5d..e09edfc 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1832,6 +1832,13 @@ static int xdst_queue_output(struct sk_buff *skb)
 	struct dst_entry *dst = skb_dst(skb);
 	struct xfrm_dst *xdst = (struct xfrm_dst *) dst;
 	struct xfrm_policy_queue *pq = &xdst->pols[0]->polq;
+	const struct sk_buff *fclone = skb + 1;
+
+	if (unlikely(skb->fclone == SKB_FCLONE_ORIG &&
+		     fclone->fclone == SKB_FCLONE_CLONE)) {
+		kfree_skb(skb);
+		return 0;
+	}
 
 	if (pq->hold_queue.qlen > XFRM_MAX_QUEUE_LEN) {
 		kfree_skb(skb);
-- 
1.7.9.5