From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: Re: [PATCH net-next v3 4/5] net/tc: introduce TC_ACT_REINJECT. Date: Wed, 25 Jul 2018 14:57:38 +0200 Message-ID: <20180725125738.GH2164@nanopsycho> References: <3c20787be0fd5d64728ffed46ae0a7dff10d7e05.1532437050.git.pabeni@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, Jamal Hadi Salim , Cong Wang , Daniel Borkmann , Marcelo Ricardo Leitner , Eyal Birger , "David S. Miller" To: Paolo Abeni Return-path: Received: from mail-wr1-f67.google.com ([209.85.221.67]:37764 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728927AbeGYOLl (ORCPT ); Wed, 25 Jul 2018 10:11:41 -0400 Received: by mail-wr1-f67.google.com with SMTP id q10-v6so7328219wrd.4 for ; Wed, 25 Jul 2018 06:00:05 -0700 (PDT) Content-Disposition: inline In-Reply-To: <3c20787be0fd5d64728ffed46ae0a7dff10d7e05.1532437050.git.pabeni@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: Tue, Jul 24, 2018 at 10:06:42PM CEST, pabeni@redhat.com wrote: >This is similar TC_ACT_REDIRECT, but with a slightly different >semantic: >- on ingress the mirred skbs are passed to the target device >network stack without any additional check not scrubbing. >- the rcu-protected stats provided via the tcf_result struct > are updated on error conditions. > >This new tcfa_action value is not exposed to the user-space >and can be used only internally by clsact. > >v1 -> v2: do not touch TC_ACT_REDIRECT code path, introduce > a new action type instead > >v2 -> v3: > - rename the new action value TC_ACT_REINJECT, update the > helper accordingly > - take care of uncloned reinjected packets in XDP generic > hook > >Signed-off-by: Paolo Abeni >--- > include/net/pkt_cls.h | 3 +++ > include/net/sch_generic.h | 19 +++++++++++++++++++ > net/core/dev.c | 6 +++++- > 3 files changed, 27 insertions(+), 1 deletion(-) > >diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h >index 2081e4219f81..36ccfe2a303a 100644 >--- a/include/net/pkt_cls.h >+++ b/include/net/pkt_cls.h >@@ -7,6 +7,9 @@ > #include > #include > >+/* TC action not accessible from user space */ >+#define TC_ACT_REINJECT (TC_ACT_VALUE_MAX + 1) >+ > /* Basic packet classifier frontend definitions. */ > > struct tcf_walker { >diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h >index 056dc1083aa3..95e81a70f549 100644 >--- a/include/net/sch_generic.h >+++ b/include/net/sch_generic.h >@@ -235,6 +235,12 @@ struct tcf_result { > u32 classid; > }; > const struct tcf_proto *goto_tp; >+ >+ /* used by the TC_ACT_REINJECT action */ >+ struct { >+ bool ingress; >+ struct gnet_stats_queue *qstats; >+ }; > }; > }; > >@@ -1091,4 +1097,17 @@ void mini_qdisc_pair_swap(struct mini_Qdisc_pair *miniqp, > void mini_qdisc_pair_init(struct mini_Qdisc_pair *miniqp, struct Qdisc *qdisc, > struct mini_Qdisc __rcu **p_miniq); > >+static inline void skb_tc_reinject(struct sk_buff *skb, struct tcf_result *res) >+{ >+ struct gnet_stats_queue *stats = res->qstats; >+ int ret; >+ >+ if (res->ingress) >+ ret = netif_receive_skb(skb); >+ else >+ ret = dev_queue_xmit(skb); Hmm. "reinject" by the name tells me that the packet should be injected again. By "inject", I understand beginning of the rx path. However, this does xmit as well :/ It is a bit misleading. Maybe "reinsert" would sound better? >+ if (ret && stats) >+ qstats_overlimit_inc(res->qstats); >+} >+ > #endif >diff --git a/net/core/dev.c b/net/core/dev.c >index 14a748ee8cc9..826ec74fe1d9 100644 >--- a/net/core/dev.c >+++ b/net/core/dev.c >@@ -4252,7 +4252,7 @@ static u32 netif_receive_generic_xdp(struct sk_buff *skb, > /* Reinjected packets coming from act_mirred or similar should > * not get XDP generic processing. > */ >- if (skb_cloned(skb)) >+ if (skb_cloned(skb) || skb->tc_redirected) > return XDP_PASS; > > /* XDP packets must be linear and must have sufficient headroom >@@ -4602,6 +4602,10 @@ sch_handle_ingress(struct sk_buff *skb, struct packet_type **pt_prev, int *ret, > __skb_push(skb, skb->mac_len); > skb_do_redirect(skb); > return NULL; >+ case TC_ACT_REINJECT: >+ /* this does not scrub the packet, and updates stats on error */ >+ skb_tc_reinject(skb, &cl_res); >+ return NULL; > default: > break; > } >-- >2.17.1 >