netdev - [PATCH] net: Validate frames going through the direct

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Date:	Tue, 02 Sep 2014 18:55:48 -0400
From:	Alexander Duyck <alexander.h.duyck@...el.com>
To:	netdev@...r.kernel.org, davem@...emloft.net
Subject: [PATCH] net: Validate frames going through the direct_xmit path

In commit 50cbe9ab5f8d92d2d4a327b56e96559d8f63a1fa "net: Validate xmit SKBs
right when we pull them out of the qdisc" the validation code was moved out
of dev_hard_start_xmit and into dequeue_skb.  However this overlooked the
fact that we do not always enqueue the skb onto a qdisc.

As a result I was seeing issues trying to connect to a vhost_net interface
after this patch was applied.  To resolve the issue I have added a call to
validate_xmit_skb in sched_direct_xmit and this seems to have resolved the
issue by restoring the validation to this xmit path.

Signed-off-by: Alexander Duyck <alexander.h.duyck@...el.com>
---
 net/sched/sch_generic.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index a8bf9f9..203ee65 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -128,8 +128,13 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
 	spin_unlock(root_lock);

 	HARD_TX_LOCK(dev, txq, smp_processor_id());
-	if (!netif_xmit_frozen_or_stopped(txq))
-		skb = dev_hard_start_xmit(skb, dev, txq, &ret);
+	if (!netif_xmit_frozen_or_stopped(txq)) {
+		skb = validate_xmit_skb(skb, dev);
+		if (!skb)
+			ret = NETDEV_TX_OK;
+		else
+			skb = dev_hard_start_xmit(skb, dev, txq, &ret);
+	}

 	HARD_TX_UNLOCK(dev, txq);

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