From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: [PATCH 36/53] netfilter: xt_TCPMSS: Refactor the codes to decrease one condition check and more readable Date: Mon, 26 Sep 2016 01:06:46 +0200 Message-ID: <1474844823-2026-37-git-send-email-pablo@netfilter.org> References: <1474844823-2026-1-git-send-email-pablo@netfilter.org> Cc: davem@davemloft.net, netdev@vger.kernel.org To: netfilter-devel@vger.kernel.org Return-path: Received: from mail.us.es ([193.147.175.20]:54750 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1034826AbcIYXH5 (ORCPT ); Sun, 25 Sep 2016 19:07:57 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id EFB5FC109C for ; Mon, 26 Sep 2016 01:07:55 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id DE290DA817 for ; Mon, 26 Sep 2016 01:07:55 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id BC510DA818 for ; Mon, 26 Sep 2016 01:07:53 +0200 (CEST) In-Reply-To: <1474844823-2026-1-git-send-email-pablo@netfilter.org> Sender: netdev-owner@vger.kernel.org List-ID: From: Gao Feng The origin codes perform two condition checks with dst_mtu(skb_dst(skb)) and in_mtu. And the last statement is "min(dst_mtu(skb_dst(skb)), in_mtu) - minlen". It may let reader think about how about the result. Would it be negative. Now assign the result of min(dst_mtu(skb_dst(skb)), in_mtu) to a new variable, then only perform one condition check, and it is more readable. Signed-off-by: Gao Feng Signed-off-by: Pablo Neira Ayuso --- net/netfilter/xt_TCPMSS.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/net/netfilter/xt_TCPMSS.c b/net/netfilter/xt_TCPMSS.c index e118397254af..872db2d0e2a9 100644 --- a/net/netfilter/xt_TCPMSS.c +++ b/net/netfilter/xt_TCPMSS.c @@ -110,18 +110,14 @@ tcpmss_mangle_packet(struct sk_buff *skb, if (info->mss == XT_TCPMSS_CLAMP_PMTU) { struct net *net = par->net; unsigned int in_mtu = tcpmss_reverse_mtu(net, skb, family); + unsigned int min_mtu = min(dst_mtu(skb_dst(skb)), in_mtu); - if (dst_mtu(skb_dst(skb)) <= minlen) { + if (min_mtu <= minlen) { net_err_ratelimited("unknown or invalid path-MTU (%u)\n", - dst_mtu(skb_dst(skb))); + min_mtu); return -1; } - if (in_mtu <= minlen) { - net_err_ratelimited("unknown or invalid path-MTU (%u)\n", - in_mtu); - return -1; - } - newmss = min(dst_mtu(skb_dst(skb)), in_mtu) - minlen; + newmss = min_mtu - minlen; } else newmss = info->mss; -- 2.1.4