Subject: Re: [PATCH net-next v2] vxlan: fix handling of the inner 8021Q tagged frame

From: Toshiaki Makita <[email-masked]>
Date: Wed, 02 Apr 2014 17:30:55 +0900

(2014/04/01 23:27), Atzm Watanabe wrote:
> Currently the implementation can forward the 8021Q tagged frame,
> but the FDB cannot learn the VID.
> So there is a possibility of forwarding the frame to wrong VTEP,
> when same LLADDR exists on different VLANs.
> 
> This patch supports only single tagged frame, so the outermost
> tag will be used when handling the 8021AD Q-in-Q frame.
> 
> v2: Fix probably unsafe operation on the struct vxlan_key.
>     The outermost tag will be used when handling the 8021AD
>     Q-in-Q frame.  Based on Stephen Hemminger's comments.
> 
> Signed-off-by: Atzm Watanabe <[email-masked]>
...
> @@ -1215,8 +1257,18 @@ static void vxlan_rcv(struct vxlan_sock *vs,
>  #endif
>  	}
>  
> +	ether_addr_copy(key.eth_addr, eth_hdr(skb)->h_source);
> +	switch (ntohs(eth_hdr(skb)->h_proto)) {
> +	case ETH_P_8021Q:
> +	case ETH_P_8021AD:
> +		key.vlan_id = ntohs(vlan_eth_hdr(skb)->h_vlan_TCI) & VLAN_VID_MASK;
> +		break;

It seems that we can't segregate skbs tagged by same vlan id but
different vlan protocols.

> +	default:
> +		key.vlan_id = 0;
> +	}
> +
>  	if ((vxlan->flags & VXLAN_F_LEARN) &&
> -	    vxlan_snoop(skb->dev, &saddr, eth_hdr(skb)->h_source))
> +	    vxlan_snoop(skb->dev, &saddr, &key))
>  		goto drop;
>  
>  	skb_reset_network_header(skb);
...
> @@ -1983,23 +2056,28 @@ static netdev_tx_t vxlan_xmit(struct sk_buff *skb, struct net_device *dev)
>  #endif
>  	}
>  
> -	f = vxlan_find_mac(vxlan, eth->h_dest);
> +	ether_addr_copy(key.eth_addr, eth->h_dest);
> +	key.vlan_id = vlan_tx_tag_present(skb) ? vlan_tx_tag_get_id(skb) : 0;

Can't we assume that skbs always have HW accelarated vlan tags?

Thanks,
Toshiaki Makita