From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 17D0D1E1DA for ; Thu, 10 Aug 2023 18:13:37 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A3EAE4B for ; Thu, 10 Aug 2023 11:13:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1691691215; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=wmwHdpGZcRqvJCDowHZXOL69K5rNTDMs6Jp6nmrPZyc=; b=XKa2YkQntrzlBoVol6GehkpOixo0QEjFJPyYPWnywLriq8sDsOyRX3Ru+faAkT4VoXiMI/ u3yCTM64islOp8/wzg9FHocCmzJcvBBrqD7rqavnDeg7TM0sOWkHwMTihXbeJOF2AB0IeH FtX0BZtzkiBVUB9tW/iuTsIr+57Bz94= Received: from mimecast-mx02.redhat.com (66.187.233.73 [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-172-5ANWishAPSODNZKhlJXsow-1; Thu, 10 Aug 2023 14:13:31 -0400 X-MC-Unique: 5ANWishAPSODNZKhlJXsow-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 96D7B2834766; Thu, 10 Aug 2023 18:13:30 +0000 (UTC) Received: from RHTPC1VM0NT (unknown [10.22.34.42]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5282B492B0F; Thu, 10 Aug 2023 18:13:30 +0000 (UTC) From: Aaron Conole To: Adrian Moreno Cc: netdev@vger.kernel.org, i.maximets@ovn.org, eric@garver.life, dev@openvswitch.org Subject: Re: [net-next v4 1/7] net: openvswitch: add last-action drop reason References: <20230809153833.2363265-1-amorenoz@redhat.com> <20230809153833.2363265-2-amorenoz@redhat.com> Date: Thu, 10 Aug 2023 14:13:29 -0400 In-Reply-To: <20230809153833.2363265-2-amorenoz@redhat.com> (Adrian Moreno's message of "Wed, 9 Aug 2023 17:38:21 +0200") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Adrian Moreno writes: > Create a new drop reason subsystem for openvswitch and add the first > drop reason to represent last-action drops. > > Last-action drops happen when a flow has an empty action list or there > is no action that consumes the packet (output, userspace, recirc, etc). > It is the most common way in which OVS drops packets. > > Implementation-wise, most of these skb-consuming actions already call > "consume_skb" internally and return directly from within the > do_execute_actions() loop so with minimal changes we can assume that > any skb that exits the loop normally is a packet drop. > > Signed-off-by: Adrian Moreno > --- Overall, looks good. I did a build with this and got some warnings. I think they can be resolved in the same way the mac80211 drops are resolved by using (__force u32) to pass the reason argument. > include/net/dropreason.h | 6 ++++++ > net/openvswitch/actions.c | 12 ++++++++++-- > net/openvswitch/datapath.c | 16 ++++++++++++++++ > net/openvswitch/drop.h | 24 ++++++++++++++++++++++++ > 4 files changed, 56 insertions(+), 2 deletions(-) > create mode 100644 net/openvswitch/drop.h > > diff --git a/include/net/dropreason.h b/include/net/dropreason.h > index 685fb37df8e8..56cb7be92244 100644 > --- a/include/net/dropreason.h > +++ b/include/net/dropreason.h > @@ -23,6 +23,12 @@ enum skb_drop_reason_subsys { > */ > SKB_DROP_REASON_SUBSYS_MAC80211_MONITOR, > > + /** > + * @SKB_DROP_REASON_SUBSYS_OPENVSWITCH: openvswitch drop reasons, > + * see net/openvswitch/drop.h > + */ > + SKB_DROP_REASON_SUBSYS_OPENVSWITCH, > + > /** @SKB_DROP_REASON_SUBSYS_NUM: number of subsystems defined */ > SKB_DROP_REASON_SUBSYS_NUM > }; > diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c > index cab1e02b63e0..1234e95a9ce8 100644 > --- a/net/openvswitch/actions.c > +++ b/net/openvswitch/actions.c > @@ -27,6 +27,7 @@ > #include > > #include "datapath.h" > +#include "drop.h" > #include "flow.h" > #include "conntrack.h" > #include "vport.h" > @@ -1036,7 +1037,7 @@ static int sample(struct datapath *dp, struct sk_buff *skb, > if ((arg->probability != U32_MAX) && > (!arg->probability || get_random_u32() > arg->probability)) { > if (last) > - consume_skb(skb); > + kfree_skb_reason(skb, OVS_DROP_LAST_ACTION); > return 0; > } > > @@ -1297,6 +1298,9 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, > if (trace_ovs_do_execute_action_enabled()) > trace_ovs_do_execute_action(dp, skb, key, a, rem); > > + /* Actions that rightfully have to consume the skb should do it > + * and return directly. > + */ > switch (nla_type(a)) { > case OVS_ACTION_ATTR_OUTPUT: { > int port = nla_get_u32(a); > @@ -1332,6 +1336,10 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, > output_userspace(dp, skb, key, a, attr, > len, OVS_CB(skb)->cutlen); > OVS_CB(skb)->cutlen = 0; > + if (nla_is_last(a, rem)) { > + consume_skb(skb); > + return 0; > + } > break; > > case OVS_ACTION_ATTR_HASH: > @@ -1485,7 +1493,7 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb, > } > } > > - consume_skb(skb); > + kfree_skb_reason(skb, OVS_DROP_LAST_ACTION); > return 0; > } > > diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c > index a6d2a0b1aa21..d33cb739883f 100644 > --- a/net/openvswitch/datapath.c > +++ b/net/openvswitch/datapath.c > @@ -41,6 +41,7 @@ > #include > > #include "datapath.h" > +#include "drop.h" > #include "flow.h" > #include "flow_table.h" > #include "flow_netlink.h" > @@ -2702,6 +2703,17 @@ static struct pernet_operations ovs_net_ops = { > .size = sizeof(struct ovs_net), > }; > > +static const char * const ovs_drop_reasons[] = { > +#define S(x) (#x), > + OVS_DROP_REASONS(S) > +#undef S > +}; > + > +static struct drop_reason_list drop_reason_list_ovs = { > + .reasons = ovs_drop_reasons, > + .n_reasons = ARRAY_SIZE(ovs_drop_reasons), > +}; > + > static int __init dp_init(void) > { > int err; > @@ -2743,6 +2755,9 @@ static int __init dp_init(void) > if (err < 0) > goto error_unreg_netdev; > > + drop_reasons_register_subsys(SKB_DROP_REASON_SUBSYS_OPENVSWITCH, > + &drop_reason_list_ovs); > + > return 0; > > error_unreg_netdev: > @@ -2769,6 +2784,7 @@ static void dp_cleanup(void) > ovs_netdev_exit(); > unregister_netdevice_notifier(&ovs_dp_device_notifier); > unregister_pernet_device(&ovs_net_ops); > + drop_reasons_unregister_subsys(SKB_DROP_REASON_SUBSYS_OPENVSWITCH); > rcu_barrier(); > ovs_vport_exit(); > ovs_flow_exit(); > diff --git a/net/openvswitch/drop.h b/net/openvswitch/drop.h > new file mode 100644 > index 000000000000..ffdb8ab045bd > --- /dev/null > +++ b/net/openvswitch/drop.h > @@ -0,0 +1,24 @@ > +/* SPDX-License-Identifier: GPL-2.0-only */ > +/* > + * OpenvSwitch drop reason list. > + */ > + > +#ifndef OPENVSWITCH_DROP_H > +#define OPENVSWITCH_DROP_H > +#include > + > +#define OVS_DROP_REASONS(R) \ > + R(OVS_DROP_LAST_ACTION) \ > + /* deliberate comment for trailing \ */ > + > +enum ovs_drop_reason { > + __OVS_DROP_REASON = SKB_DROP_REASON_SUBSYS_OPENVSWITCH << > + SKB_DROP_REASON_SUBSYS_SHIFT, > +#define ENUM(x) x, > + OVS_DROP_REASONS(ENUM) > +#undef ENUM > + > + OVS_DROP_MAX, > +}; > + > +#endif /* OPENVSWITCH_DROP_H */