netdev - Re: VLAN packets silently dropped in promiscuous mode

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Date:	Thu, 30 Sep 2010 14:16:44 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Patrick McHardy <kaber@...sh.net>
Cc:	Roger Luethi <rl@...lgate.ch>, David Miller <davem@...emloft.net>,
	Jesse Gross <jesse@...ira.com>, netdev@...r.kernel.org
Subject: Re: VLAN packets silently dropped in promiscuous mode

Le jeudi 30 septembre 2010 à 12:50 +0200, Patrick McHardy a écrit :

> This should be fine as long as the packets are properly marked
> with PACKET_OTHERHOST.

Ah thanks Patrick for the tip !

I tested following patch on tg3 and it is doing the right thing this
time.


[PATCH] vlan: dont drop packets from unknown vlans in promiscuous mode

Roger Luethi noticed packets for unknown VLANs getting silently dropped
even in promiscuous mode.

Check for promiscuous mode in __vlan_hwaccel_rx() and vlan_gro_common()
before drops.

As suggested by Patrick, mark such packets to have skb->pkt_type set to
PACKET_OTHERHOST to make sure they are dropped by IP stack.

Reported-by: Roger Luethi <rl@...lgate.ch>
Signed-off-by: Eric Dumazet <eric.dumazet@...il.com>
CC: Patrick McHardy <kaber@...sh.net>
---
 net/8021q/vlan_core.c |   14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/net/8021q/vlan_core.c b/net/8021q/vlan_core.c
index 01ddb04..0eb96f7 100644
--- a/net/8021q/vlan_core.c
+++ b/net/8021q/vlan_core.c
@@ -24,8 +24,11 @@ int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp,
 
 	if (vlan_dev)
 		skb->dev = vlan_dev;
-	else if (vlan_id)
-		goto drop;
+	else if (vlan_id) {
+		if (!(skb->dev->flags & IFF_PROMISC))
+			goto drop;
+		skb->pkt_type = PACKET_OTHERHOST;
+	}
 
 	return (polling ? netif_receive_skb(skb) : netif_rx(skb));
 
@@ -102,8 +105,11 @@ vlan_gro_common(struct napi_struct *napi, struct vlan_group *grp,
 
 	if (vlan_dev)
 		skb->dev = vlan_dev;
-	else if (vlan_id)
-		goto drop;
+	else if (vlan_id) {
+		if (!(skb->dev->flags & IFF_PROMISC))
+			goto drop;
+		skb->pkt_type = PACKET_OTHERHOST;
+	}
 
 	for (p = napi->gro_list; p; p = p->next) {
 		NAPI_GRO_CB(p)->same_flow =


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