From: Bjørn Mork <bj...@mork.no> Date: Tue, 17 Apr 2018 00:00:38 +0200
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 28583aa0c17d..01cf8e3d8edc 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1103,13 +1103,6 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, > struct net_device *dev) > > len = run_ebpf_filter(tun, skb, len); > > - /* Trim extra bytes since we may insert vlan proto & TCI > - * in tun_put_user(). > - */ > - len -= skb_vlan_tag_present(skb) ? sizeof(struct veth) : 0; > - if (len <= 0 || pskb_trim(skb, len)) > - goto drop; > - > if (unlikely(skb_orphan_frags_rx(skb, GFP_ATOMIC))) The VLAN business might be bogus, and needs to be removed. However, the pskb_trim() has to stay in some form. I think this is what Jason is trying to say. The semantics of running a BPF program is that the program returns the desired packet length. We must truncate the packet to the length returned by the BPF program, therefore.
