From nobody Tue Aug 29 01:23:33 2023 X-Original-To: freebsd-net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4RZV7L3Wkkz4s9KV for ; Tue, 29 Aug 2023 01:23:42 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4RZV7K6vJqz3JWR; Tue, 29 Aug 2023 01:23:41 +0000 (UTC) (envelope-from kostikbel@gmail.com) Authentication-Results: mx1.freebsd.org; none Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.17.1/8.17.1) with ESMTPS id 37T1NXcY084215 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Tue, 29 Aug 2023 04:23:36 +0300 (EEST) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua 37T1NXcY084215 Received: (from kostik@localhost) by tom.home (8.17.1/8.17.1/Submit) id 37T1NXlC084214; Tue, 29 Aug 2023 04:23:33 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Tue, 29 Aug 2023 04:23:33 +0300 From: Konstantin Belousov To: Zhenlei Huang Cc: freebsd-net Subject: Re: About IFNET_PCP_NONE Message-ID: References: <20ECDA33-2638-4CFB-8740-5E8BF1F8072B@FreeBSD.org> List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20ECDA33-2638-4CFB-8740-5E8BF1F8072B@FreeBSD.org> X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM, NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=4.0.0 X-Spam-Checker-Version: SpamAssassin 4.0.0 (2022-12-14) on tom.home X-Spamd-Bar: ---- X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:6939, ipnet:2001:470::/32, country:US] X-Rspamd-Queue-Id: 4RZV7K6vJqz3JWR On Mon, Aug 28, 2023 at 10:25:01PM +0800, Zhenlei Huang wrote: > > > > On Aug 28, 2023, at 3:54 PM, Konstantin Belousov wrote: > > > > On Mon, Aug 28, 2023 at 09:51:38AM +0800, Zhenlei Huang wrote: > >> Hi Konstantin, > >> > >> > >> I was just about going to open a PR for https://reviews.freebsd.org/D39536 and > >> realized I might made wrong assumption. > >> > >> I thought IFNET_PCP_NONE is something like IEEE8021Q_PCP_BE but I second why not > >> use IEEE8021Q_PCP_BE but a new const IFNET_PCP_NONE. > > I meant > > ``` > int > ether_output_frame(struct ifnet *ifp, struct mbuf *m) > { > uint8_t pcp; > > pcp = ifp->if_pcp; > if (pcp != 0 /* IEEE8021Q_PCP_BE */ && ifp->if_type != IFT_L2VLAN && > !ether_set_pcp(&m, ifp, pcp)) > return (0); > > ... This is wrong. PCP_BE is just one of the priorities, that should allowed to be specified in the 802.1q pseudo-vlan header. > > } > ``` > > >> > >> So despite its naming IFNET_PCP_NONE, is it actually a flag to let specific interface > >> completely bypass (disable) PCP processing? > >> > >> The const IFNET_PCP_NONE is defined in sys/net/if.h with > >> ``` > >> #define IFNET_PCP_NONE 0xff /* PCP disabled */ > >> ``` > > I fail to understand your question. > > > > IFNET_PCP_NONE is a value that means that no 802.1q prio is inserted into > > the packet. Otherwise, non-vlan traffic is tagged with the priority. > > Think about the following case: > > 1. Set interface's PCP to IFNET_PCP_NONE, application / firewall provide per-flow PCP, should > the traffic be tagged with the priority ? Yes, it should, but only for packets from the specified flows. > > > > > > IEEE8021Q_PCP_BE is a name of one of the priorities, it seems from my > > code reading. > > > Best regards, > Zhenlei >