Commit 6671b224 authored Feb 18, 2014 by Fernando Luis Vazquez Cao Committed by David S. Miller Feb 20, 2014

tun: remove bogus hardware vlan acceleration flags from vlan_features



Even though only the outer vlan tag can be HW accelerated in the transmission
path, in the TUN/TAP driver vlan_features mirrors hw_features, which happens
to have the NETIF_F_HW_VLAN_?TAG_TX flags set. Because of this, during packet
tranmisssion through a stacked vlan device dev_hard_start_xmit, (incorrectly)
assuming that the vlan device supports hardware vlan acceleration, does not
add the vlan header to the skb payload and the inner vlan tags are lost
(vlan_tci contains the outer vlan tag when userspace reads the packet from
the tap device).

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 8d0d21f4

drivers/net/tun.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -1686,7 +1686,9 @@ static int tun_set_iff(struct net net, struct file file, struct ifreq *ifr)
		TUN_USER_FEATURES \| NETIF_F_HW_VLAN_CTAG_TX \|
		NETIF_F_HW_VLAN_STAG_TX;
		dev->features = dev->hw_features;
		dev->vlan_features = dev->features;
		dev->vlan_features = dev->features &
		~(NETIF_F_HW_VLAN_CTAG_TX \|
		NETIF_F_HW_VLAN_STAG_TX);

		INIT_LIST_HEAD(&tun->disabled);
		err = tun_attach(tun, file, false);

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