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HTB/8021q: That was my fault

Regarding the problem with shaping vlan-tagged traffic on linux bridge — it was my fault :-)

I asked community@lists.altlinux.org, and Sergey Vlasov answered me with some info and hint — thanks a lot!-)

As Sergey told, «a packet is being passed to bridge module before 8021q can process it». That’s why the classifier decides that a packet does not match a filter rule — because filter contains «protocol ip» condition, however a packet contains «protocol 802.1q» actually. It look like it’s enough to use «protocol 802.1q» in filter condition — after that ip addresses (offsets from IP packet’s start) will be counted correctly.

This offers a possibility to build «aggregating shapers» on linux bridges, which will be able to shaper clients” traffic regardless of «traffic direction» (regardless of a particular vlan membership). And it will be very easy to migrate from an «usual» shaper on linux bridge — we will have to replace «protocol ip» with «protocol 802.1q» in a filter template (or we can add one more filter — if it is really necessary).

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2 коментарі to “HTB/8021q: That was my fault”

  1. ilj says:

    So, is this working or not? I personally failed to “capture” 802.1q tagged traffic using this type of filter. After googling around I started to come to realization that it might work but not for everyone (I don’t know the reasons).

    Could you please elaborate on the idea described in this post?

    • dor says:

      Yes! It works.

      Now my shaper has a lot of lines like this:

      /sbin/tc filter add dev clients0 protocol 802.1q parent 1:0 prio 100 u32 ht 133:54 match ip dst XX.YY.133.84 flowid 1:2e2

      It shapes tagged traffic on “untagged” (physical) interfaces (“clients0” is a renamed physical ethX — can’t remember which one).

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