From 6671b2240c54585d4afb5286a29f1569fe5e40a8 Mon Sep 17 00:00:00 2001 From: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> Date: Tue, 18 Feb 2014 21:20:09 +0900 Subject: [PATCH] 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> --- drivers/net/tun.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 8fe9cb7d0f72..26f8635b027d 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -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); -- GitLab