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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT 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 B5D09C04AB6 for ; Fri, 31 May 2019 09:30:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F9A8266CB for ; Fri, 31 May 2019 09:30:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726280AbfEaJaO (ORCPT ); Fri, 31 May 2019 05:30:14 -0400 Received: from orbyte.nwl.cc ([151.80.46.58]:45034 "EHLO orbyte.nwl.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726232AbfEaJaO (ORCPT ); Fri, 31 May 2019 05:30:14 -0400 Received: from n0-1 by orbyte.nwl.cc with local (Exim 4.91) (envelope-from ) id 1hWdrY-00063e-DK; Fri, 31 May 2019 11:30:12 +0200 Date: Fri, 31 May 2019 11:30:12 +0200 From: Phil Sutter To: Pablo Neira Ayuso Cc: netfilter-devel@vger.kernel.org Subject: Re: [PATCH nft,v3 2/7] mnl: mnl_set_rcvbuffer() skips buffer size update if it is too small Message-ID: <20190531093012.GH31548@orbyte.nwl.cc> Mail-Followup-To: Phil Sutter , Pablo Neira Ayuso , netfilter-devel@vger.kernel.org References: <20190530111246.14550-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190530111246.14550-1-pablo@netfilter.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Hi Pablo, On Thu, May 30, 2019 at 01:12:46PM +0200, Pablo Neira Ayuso wrote: > Check for existing buffer size, if this is larger than the newer buffer > size, skip this size update. > > Signed-off-by: Pablo Neira Ayuso > --- > v3: 'len' variable was not properly set. > > src/mnl.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/src/mnl.c b/src/mnl.c > index 288a887df097..2270a084ad29 100644 > --- a/src/mnl.c > +++ b/src/mnl.c > @@ -235,8 +235,15 @@ static void mnl_set_sndbuffer(const struct mnl_socket *nl, > > static int mnl_set_rcvbuffer(const struct mnl_socket *nl, size_t bufsiz) > { > + unsigned int cur_bufsiz; > + socklen_t len = sizeof(cur_bufsiz); > int ret; > > + ret = getsockopt(mnl_socket_get_fd(nl), SOL_SOCKET, SO_RCVBUF, > + &cur_bufsiz, &len); > + if (cur_bufsiz > bufsiz) > + return 0; > + For mnl_set_sndbuffer(), there is simply a global static variable holding the last set value. Can't we use that here as well? I think of something like: + static unsigned int nlsndbufsiz; static int mnl_set_rcvbuffer(const struct mnl_socket *nl, size_t bufsiz) { + socklen_t len = sizeof(nlsndbufsiz); int ret; + if (!nlsndbufsiz) + ret = getsockopt(mnl_socket_get_fd(nl), SOL_SOCKET, SO_RCVBUF, + &nlsndbufsiz, &len); + if (nlsndbufsiz >= bufsiz) + return 0; Cheers, Phil