From: Petr Machata <petrm@nvidia.com>
To: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Petr Machata <petrm@nvidia.com>, <netdev@vger.kernel.org>,
Jiri Pirko <jiri@nvidia.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Ido Schimmel <idosch@nvidia.com>,
Cong Wang <xiyou.wangcong@gmail.com>
Subject: Re: [PATCH net-next 1/7] net: sched: Add a trap-and-forward action
Date: Fri, 9 Apr 2021 13:03:19 +0200 [thread overview]
Message-ID: <877dlb67pk.fsf@nvidia.com> (raw)
In-Reply-To: <b60df78a-1aba-ba27-6508-4c67b0496020@mojatatu.com>
Jamal Hadi Salim <jhs@mojatatu.com> writes:
> I am concerned about adding new opcodes which only make sense if you
> offload (or make sense only if you are running in s/w).
>
> Those opcodes are intended to be generic abstractions so the dispatcher
> can decide what to do next. Adding things that are specific only
> to scenarios of hardware offload removes that opaqueness.
> I must have missed the discussion on ACT_TRAP because it is the
> same issue there i.e shouldnt be an opcode. For details see:
> https://people.netfilter.org/pablo/netdev0.1/papers/Linux-Traffic-Control-Classifier-Action-Subsystem-Architecture.pdf
Trap has been in since 4.13, so 2017ish. It's done and dusted at this
point.
> IMO:
> It seems to me there are two actions here encapsulated in one.
> The first is to "trap" and the second is to "drop".
>
> This is no different semantically than say "mirror and drop"
> offload being enunciated by "skip_sw".
>
> Does the spectrum not support multiple actions?
> e.g with a policy like:
> match blah action trap action drop skip_sw
Trap drops implicitly. We need a "trap, but don't drop". Expressed in
terms of existing actions it would be "mirred egress redirect dev
$cpu_port". But how to express $cpu_port except again by a HW-specific
magic token I don't know.
next prev parent reply other threads:[~2021-04-09 11:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 13:38 [PATCH net-next 0/7] tc: Introduce a trap-and-forward action Petr Machata
2021-04-08 13:38 ` [PATCH net-next 1/7] net: sched: Add " Petr Machata
2021-04-08 14:05 ` Jamal Hadi Salim
2021-04-08 21:25 ` Jakub Kicinski
2021-04-09 11:13 ` Jamal Hadi Salim
2021-04-09 11:03 ` Petr Machata [this message]
2021-04-09 11:44 ` Jamal Hadi Salim
2021-04-09 13:43 ` Petr Machata
2021-04-11 19:23 ` Jamal Hadi Salim
2021-04-08 13:38 ` [PATCH net-next 2/7] net: sched: Make the action trap_fwd offloadable Petr Machata
2021-04-08 13:38 ` [PATCH net-next 3/7] devlink: Add a new trap for the trap_fwd action Petr Machata
2021-04-08 13:38 ` [PATCH net-next 4/7] mlxsw: Propagate extack to mlxsw_afa_block_commit() Petr Machata
2021-04-08 13:38 ` [PATCH net-next 5/7] mlxsw: Offload trap_fwd Petr Machata
2021-04-08 13:38 ` [PATCH net-next 6/7] selftests: forwarding: Add a test for TC trapping behavior Petr Machata
2021-04-08 13:38 ` [PATCH net-next 7/7] selftests: mlxsw: Add a trap_fwd test to devlink_trap_control Petr Machata
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