Thanks for the response. > It sounds like you are running at userlevel, and that you are using METHOD > PCAP (which is the default in recent versions)? Do let us know if you > discover more. You could also try METHOD LINUX, although this is slower than > pcap I believe.
Yes I am at userlevel and was using METHOD PCAP. I just tried using METHOD LINUX and the problem persists. Summary: The problem is still not resolved by either the linux kernel or libpcap, and although it's not directly a click problem, it does impact packets generated by click. Details: -In Linux 3.0 and later RX packets had their vlan headers stripped and added to the skb meta data (skb->vlan_tci). This created a bug where libpcap was unable to perform any kernel based filtering based on vlans. -In Linux 3.8 a new BPF ancillary function will be introduced to give BPF access to the skb->vlan_tci -A RFC's patch on the libpcap mailing list gives libpcap the ability to generate kernel packet filters that use skb->vlan_tci -TX packets (**which is the category injected click packets fall into**) do not have skb->vlan_tci set, which is the current sticking point. The current issue is the libpcap developers feel that TX packets should have the same properties as RX packet. They feel that libpcap should be able to generate a single filter that looks at skb->vlan_tci. The linux kernel developers disagree and suggest that libpcap generate filter code that checks skb->vlan_tci, and if that is not set falls back to the old method of probing the headers. I do not think I'm knowledgeable enough of either code base to comment on which side is right. Although I will say I'm a bit confused about why TX skb->vlan_tci isn't set. And that's where the issue stands. Neither side is commenting on the issue further, and no patches have been submitted. As far as I can tell I'm the only one who has a vested interest in fixing this. =) As a temporary workaround I discovered if I Tee all packets and send them to a fake TUN interface (ToHost) and attach libpcap to that interface, all packets have skb->vlan_tci set and the RFC's libpcap patch works. So I've been using that as a stop-gap. _______________________________________________ click mailing list [email protected] https://amsterdam.lcs.mit.edu/mailman/listinfo/click
