From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22213C48BDF for ; Thu, 24 Jun 2021 03:49:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0588C613C7 for ; Thu, 24 Jun 2021 03:49:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229906AbhFXDvW (ORCPT ); Wed, 23 Jun 2021 23:51:22 -0400 Received: from mailgw02.mediatek.com ([210.61.82.184]:39818 "EHLO mailgw02.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S229850AbhFXDvW (ORCPT ); Wed, 23 Jun 2021 23:51:22 -0400 X-UUID: 0e541a2a7cb5412db0d434357bec808b-20210624 X-UUID: 0e541a2a7cb5412db0d434357bec808b-20210624 Received: from mtkcas06.mediatek.inc [(172.21.101.30)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 358019924; Thu, 24 Jun 2021 11:48:58 +0800 Received: from mtkcas10.mediatek.inc (172.21.101.39) by mtkmbs08n2.mediatek.inc (172.21.101.56) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 24 Jun 2021 11:48:56 +0800 Received: from localhost.localdomain (10.15.20.246) by mtkcas10.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 24 Jun 2021 11:48:54 +0800 From: Rocco Yue To: Greg KH CC: "David S . Miller" , Jakub Kicinski , Jonathan Corbet , Hideaki YOSHIFUJI , David Ahern , Matthias Brugger , Felix Fietkau , John Crispin , Sean Wang , Mark Lee , , , , , , , , , , Rocco Yue Subject: Re: [PATCH 1/4] net: if_arp: add ARPHRD_PUREIP type Date: Thu, 24 Jun 2021 11:33:53 +0800 Message-ID: <20210624033353.25636-1-rocco.yue@mediatek.com> X-Mailer: git-send-email 2.18.0 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain X-MTK: N Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, 2021-06-23 at 19:19 +0200, Greg KH wrote: On Wed, Jun 23, 2021 at 07:34:49PM +0800, Rocco Yue wrote: >> This patch add the definition of ARPHRD_PUREIP which can for >> example be used by mobile ccmni device as device type. >> ARPHRD_PUREIP means that this device doesn't need kernel to >> generate ipv6 link-local address in any addr_gen_mode. >> >> Signed-off-by: Rocco Yue >> --- >> include/uapi/linux/if_arp.h | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/include/uapi/linux/if_arp.h b/include/uapi/linux/if_arp.h >> index c3cc5a9e5eaf..4463c9e9e8b4 100644 >> --- a/include/uapi/linux/if_arp.h >> +++ b/include/uapi/linux/if_arp.h >> @@ -61,6 +61,7 @@ >> #define ARPHRD_DDCMP 517 /* Digital's DDCMP protocol */ >> #define ARPHRD_RAWHDLC 518 /* Raw HDLC */ >> #define ARPHRD_RAWIP 519 /* Raw IP */ >> +#define ARPHRD_PUREIP 520 /* Pure IP */ > > In looking at the patches, what differs "PUREIP" from "RAWIP"? It seems Thanks for your review. The difference between RAWIP and PUREIP is that they generate IPv6 link-local address and IPv6 global address in different ways. RAWIP: ~~~~~~ In the ipv6_generate_eui64() function, using RAWIP will always return 0, which will cause the kernel to automatically generate an IPv6 link-local address in EUI64 format and an IPv6 global address in EUI64 format. PUREIP: ~~~~~~~ After this patch set, when using PUREIP, kernel doesn't generate IPv6 link-local address regardless of which IN6_ADDR_GEN_MODE is used. @@ static void addrconf_dev_config(struct net_device *dev) + if (dev->type == ARPHRD_PUREIP) + return; And after recving RA message, kernel iterates over the link-local address that exists for the interface and uses the low 64bits of the link-local address to generate the IPv6 global address. The general process is as follows: ndisc_router_discovery() -> addrconf_prefix_rcv() -> ipv6_generate_eui64() -> ipv6_inherit_eui64() > to be the same to me. If they are different, where is that documented? > > thanks, > > greg k-h I tried to find corresponding documents about other device types, but I am sorry I didn't find it. If it is needed, I am willing to provide. Thanks, Rocco