On Tue, Jan 1, 2019 at 11:46 AM Bartek Kois <bartek.k...@gmail.com> wrote: > > Hi > Yes it did work since I remember (like around 2.4.x) and it changed > since I moved from Debian 8 to 9. I would appreciate fixing that in the > future beacuse it is essential for queueing traffic on the routers, but > the question is why these filters don`t work in that case: > > tc filter add dev $LAN_ETH parent 1:0 protocol ip prio 4 u32 match > u32 0x0a000c08 0xffffffff at 20 classid 1:2001 # for 10.0.12.8 ip > address > tc filter add dev $LAN_ETH parent 1:0 protocol ip prio 4 u32 match > u32 0x0a000c09 0xffffffff at 20 classid 1:2002 # for 10.0.12.9 ip > address > tc filter add dev $LAN_ETH parent 1:0 protocol ip prio 4 u32 match > u32 0x0a000c10 0xffffffff at 20 classid 1:2003 # for 10.0.12.10 ip > address > > I`ve changed "at 16" which works without vlan tags to "at 20" to take > vlan tag into account.
Yeah, this confirms my speculation. The problem is essentially a design flaw of u32 filter, the IP header and TCP header offsets are never fixed, for example VLAN tagging and IP options. What's more, it is not easy for user-space to learn the offset for different packets as it requires to parse into each packets. I don't know whether we can fix this either, VLAN call path probably already makes assumptions on the current skb->data position, if we "fix" it for u32, it would probably break other things.
