On Thu, Feb 14, 2019 at 06:16:12PM +0900, Toshiaki Makita wrote: > On 2019/02/14 4:51, Zahari Doychev wrote: > > The bridge and VLAN code expects that skb->data points to the start of the > > VLAN header instead of the next (network) header. Currently after > > tcf_vlan_act() on ingress filter skb->data points to the next network > > header. In this case the Linux bridge does not forward correctly double > > tagged VLAN packets added using tc vlan action as the outer vlan tag from > > the skb is inserted at the wrong offset after the vlan tag in the payload. > > Making skb->data to point to the VLAN header in tcf_vlan_act() by using > > ETH_HLEN in skb_pull_rcsum() fixes the problem. > > > > The following commands were used for testing: > > > > ip link add name br0 type bridge vlan_filtering 1 > > ip link set dev br0 up > > > > ip link set dev net0 up > > ip link set dev net0 master br0 > > > > ip link set dev net1 up > > ip link set dev net1 master br0 > > > > bridge vlan add dev net0 vid 100 master > > bridge vlan add dev br0 vid 100 self > > bridge vlan add dev net1 vid 100 master > > > > tc qdisc add dev net0 handle ffff: clsact > > tc qdisc add dev net1 handle ffff: clsact > > > > tc filter add dev net0 ingress pref 1 protocol all flower \ > > action vlan push id 10 pipe action vlan push id 100 > > > > tc filter add dev net0 egress pref 1 protocol 802.1q flower \ > > vlan_id 100 vlan_ethtype 802.1q cvlan_id 10 \ > > action vlan pop pipe action vlan pop > > > > Signed-off-by: Zahari Doychev <zahari.doychev@xxxxxxxxx> > > --- > > net/sched/act_vlan.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c > > index 93fdaf707313..308d7d89f925 100644 > > --- a/net/sched/act_vlan.c > > +++ b/net/sched/act_vlan.c > > @@ -86,7 +86,7 @@ static int tcf_vlan_act(struct sk_buff *skb, const struct tc_action *a, > > > > out: > > if (skb_at_tc_ingress(skb)) > > - skb_pull_rcsum(skb, skb->mac_len); > > + skb_pull_rcsum(skb, ETH_HLEN); > > As I said before, it would be safer to remember mac_len and use it later. > > __u16 mac_len = skb->mac_len; > ... > err = skb_vlan_push(...) > ... > if (skb_at_tc_ingress(skb)) > skb_pull_rcsum(skb, mac_len); > sorry, I misunderstood it. I will send an update. Zahari > > -- > Toshiaki Makita >
