[Xen-devel] [PATCH 1/2] xen: netfront: refactor code for checking validity of incoming skbs

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

Makes future additional validation clearer.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
---
 drivers/net/xen-netfront.c |   24 +++++++++++++++++-------
 1 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 546de57..4dc347b 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -809,6 +809,18 @@ out:
        return err;
 }
 
+static int validate_incoming_skb(struct sk_buff *skb)
+{
+       /*
+        * If the SKB is partial then we must be able to setup the
+        * checksum fields in the skb.
+        */
+       if (skb->ip_summed == CHECKSUM_PARTIAL && skb_checksum_setup(skb))
+               return 0;
+
+       return 1;
+}
+
 static int handle_incoming_queue(struct net_device *dev,
                                 struct sk_buff_head *rxq)
 {
@@ -829,13 +841,11 @@ static int handle_incoming_queue(struct net_device *dev,
                /* Ethernet work: Delayed to here as it peeks the header. */
                skb->protocol = eth_type_trans(skb, dev);
 
-               if (skb->ip_summed == CHECKSUM_PARTIAL) {
-                       if (skb_checksum_setup(skb)) {
-                               kfree_skb(skb);
-                               packets_dropped++;
-                               dev->stats.rx_errors++;
-                               continue;
-                       }
+               if (!validate_incoming_skb(skb)) {
+                       kfree_skb(skb);
+                       packets_dropped++;
+                       dev->stats.rx_errors++;
+                       continue;
                }
 
                dev->stats.rx_packets++;
-- 
1.5.6.5


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