Re: [RFC PATCH] net/core: fix skb handling on netif serves for both bridge and vlan

[Jiri Pirko <jpirko@redhat.com>]

Thu, Mar 03, 2011 at 11:55:13AM CET, dfeng@redhat.com wrote:
>Consider network topology as follows:
>
>eth0  eth1
> |_____|
>    |
>  bond0 --- br0
>    |
>  vlan0 --- br1
>
>bond0 serves for both br0 and vlan0, if a vlan tagged packet was sent
>to br1 through bond0, bridge handling code is seeing the packet on bond0
>and handing it off to my "legacy" bridge before vlan_tx_tag_present
>and vlan_hwaccel_do_receive even haven't a chance to look at it.
>
>Moving the vlan_tx_tag_present before bridge/macvlan handling code could
>cure this.

Wouldn't this break "eth0 - br0 - br0.5"?

>
>Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
>Cc: "David S. Miller" <davem@davemloft.net>
>Cc: Eric Dumazet <eric.dumazet@gmail.com>
>Cc: Tom Herbert <therbert@google.com>
>---
> net/core/dev.c |   20 ++++++++++----------
> 1 files changed, 10 insertions(+), 10 deletions(-)
>
>diff --git a/net/core/dev.c b/net/core/dev.c
>index 8ae6631..d2d12c2 100644
>--- a/net/core/dev.c
>+++ b/net/core/dev.c
>@@ -3079,27 +3079,27 @@ static int __netif_receive_skb(struct sk_buff *skb)
> ncls:
> #endif
> 
>-	/* Handle special case of bridge or macvlan */
>-	rx_handler = rcu_dereference(skb->dev->rx_handler);
>-	if (rx_handler) {
>+	if (vlan_tx_tag_present(skb)) {
> 		if (pt_prev) {
> 			ret = deliver_skb(skb, pt_prev, orig_dev);
> 			pt_prev = NULL;
> 		}
>-		skb = rx_handler(skb);
>-		if (!skb)
>+		if (vlan_hwaccel_do_receive(&skb)) {
>+			ret = __netif_receive_skb(skb);
>+			goto out;
>+		} else if (unlikely(!skb))
> 			goto out;
> 	}
> 
>-	if (vlan_tx_tag_present(skb)) {
>+	/* Handle special case of bridge or macvlan */
>+	rx_handler = rcu_dereference(skb->dev->rx_handler);
>+	if (rx_handler) {
> 		if (pt_prev) {
> 			ret = deliver_skb(skb, pt_prev, orig_dev);
> 			pt_prev = NULL;
> 		}
>-		if (vlan_hwaccel_do_receive(&skb)) {
>-			ret = __netif_receive_skb(skb);
>-			goto out;
>-		} else if (unlikely(!skb))
>+		skb = rx_handler(skb);
>+		if (!skb)
> 			goto out;
> 	}
> 
>-- 
>1.7.1
>
>--
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