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=-7.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 46DD8C46475 for ; Thu, 25 Oct 2018 04:53:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E83032064C for ; Thu, 25 Oct 2018 04:52:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=arista.com header.i=@arista.com header.b="LG6/trAv" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E83032064C Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=arista.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727206AbeJYNX5 (ORCPT ); Thu, 25 Oct 2018 09:23:57 -0400 Received: from mail-ed1-f67.google.com ([209.85.208.67]:45167 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726527AbeJYNX5 (ORCPT ); Thu, 25 Oct 2018 09:23:57 -0400 Received: by mail-ed1-f67.google.com with SMTP id t10-v6so7139752eds.12 for ; Wed, 24 Oct 2018 21:52:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=googlenew; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=dgURxOrOIM6UEDItFy3ornyJhobgxSte/+4zp7Hb9vE=; b=LG6/trAvtBtz+0rR1/WKCo21uImO9PGEQeJJAx3t6OcdnO/WhsCz2EKhusHg19Ubao gEqeUWnjz7pHDUPwDoT+BOaJD4cSScpvxdHYwIBD7s8F4vU8Py57jS/O9bblFirKqgze TUEPMI+k4bc+aurvm00OjWMCzn3WC/WsTyWtcHib0qMhKGmcSPDUVe2DICpLpZRWB8HL eGiGDVTniDivWybpYjue33p1OiWB9INopy9fBuEfQhUgHdHvf2VozAOtIqK7S85g2KDv otRY/itcYeq7ObAykyBB1I7GGPAI+GpZ05ycBf0dDTXvCwBUjkPSSita47GjVEL6iyhw fQ5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=dgURxOrOIM6UEDItFy3ornyJhobgxSte/+4zp7Hb9vE=; b=NcL5YTqnNGwRYaj+6//fdhnhDliPi5u3SyudUSAPUdqEYzrKSbPLHn1cAuhDvXib+d ppXmmQ0u6wAFrMziLOdgUpIX0sW3aKK3SxqaA+iiFnbkZIbfB+VUqFLh3a4Hh3azcsM8 fbr5ACwK+Sare/hfgaiCxwPeu2JzvSSdiGNYx73ddkg+bOlgFAT/AQM0R0P42U9iu3Rx G55cF+nc60qzoeg9ifhD/AmL2jPijmJx6bg6GlvK1Pvppm8qCwnBxumtG2rWGKJUi3C6 o6zV+6JdbmcI4BeZZcx+Sm437BhmfJ6SjXQ8ymXtCILv0eTP5W5AXslM86zRNdFKleMw bMCw== X-Gm-Message-State: AGRZ1gLWD+F4z0vsosBUafIGLrc1QOnt0JP8hDgFGbfzGifJzA4/Rtsd Su5PYsboCfXnRBuo+as0IBrgdw== X-Google-Smtp-Source: AJdET5fLlf4ZLW+MwE/kUPu5aXMVWmXbaphSpv96Up12r1PzdFUV34oCZOCSQxv5CM6IOIf6dzfGIA== X-Received: by 2002:a50:96d1:: with SMTP id z17-v6mr316373eda.268.1540443175175; Wed, 24 Oct 2018 21:52:55 -0700 (PDT) Received: from [10.83.36.153] ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id v16-v6sm2390271edm.49.2018.10.24.21.52.53 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 Oct 2018 21:52:54 -0700 (PDT) Subject: Re: [PATCH] netfilter: conntrack: fix calculation of next bucket number in early_drop To: Vasily Khoruzhick , Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , "David S. Miller" , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org References: <20181025034853.23573-1-vasilykh@arista.com> From: Dmitry Safonov Message-ID: Date: Thu, 25 Oct 2018 05:52:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181025034853.23573-1-vasilykh@arista.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/25/18 4:48 AM, Vasily Khoruzhick wrote: > If there's no entry to drop in bucket that corresponds to the hash, > early_drop() should look for it in other buckets. But since it increments > hash instead of bucket number, it actually looks in the same bucket 8 > times: hsize is 16k by default (14 bits) and hash is 32-bit value, so > reciprocal_scale(hash, hsize) returns the same value for hash..hash+7 in > most cases. > > Fix it by increasing bucket number instead of hash and rename _hash > to bucket to avoid future confusion. > > Fixes: 3e86638e9a0b ("netfilter: conntrack: consider ct netns in early_drop logic") > Cc: # v4.7+ > Signed-off-by: Vasily Khoruzhick Nice work! Reviewed-by: Dmitry Safonov > --- > net/netfilter/nf_conntrack_core.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c > index ca1168d67fac..a04af246b184 100644 > --- a/net/netfilter/nf_conntrack_core.c > +++ b/net/netfilter/nf_conntrack_core.c > @@ -1073,19 +1073,22 @@ static unsigned int early_drop_list(struct net *net, > return drops; > } > > -static noinline int early_drop(struct net *net, unsigned int _hash) > +static noinline int early_drop(struct net *net, unsigned int hash) > { > unsigned int i; > > for (i = 0; i < NF_CT_EVICTION_RANGE; i++) { > struct hlist_nulls_head *ct_hash; > - unsigned int hash, hsize, drops; > + unsigned int bucket, hsize, drops; > > rcu_read_lock(); > nf_conntrack_get_ht(&ct_hash, &hsize); > - hash = reciprocal_scale(_hash++, hsize); > + if (!i) > + bucket = reciprocal_scale(hash, hsize); > + else > + bucket = (bucket + 1) % hsize; > > - drops = early_drop_list(net, &ct_hash[hash]); > + drops = early_drop_list(net, &ct_hash[bucket]); > rcu_read_unlock(); > > if (drops) { > -- Dima