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=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 745A8C433DB for ; Wed, 17 Feb 2021 17:09:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 43E6564E4D for ; Wed, 17 Feb 2021 17:09:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234370AbhBQRJR (ORCPT ); Wed, 17 Feb 2021 12:09:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54624 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234291AbhBQRJP (ORCPT ); Wed, 17 Feb 2021 12:09:15 -0500 Received: from mail-oi1-x236.google.com (mail-oi1-x236.google.com [IPv6:2607:f8b0:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B9B9C061574 for ; Wed, 17 Feb 2021 09:08:34 -0800 (PST) Received: by mail-oi1-x236.google.com with SMTP id 18so15710023oiz.7 for ; Wed, 17 Feb 2021 09:08:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=rTiZJmJpnBx+QEmTW+5dg14+sfV1C0crqACCRCXWPSI=; b=f5wLd0BcE4qPBF/YVnZltaa3sRBC8j1KIpZkgb0HStWzOFmxO3Pfja83FhEqIZH0f2 3CNUdo9oUsockIQCjnr6dy5E7Wq5PvhuSp9s69rNNjgWN4sNFNcmM9mZtWSVb8XMMqkS v2g2rTThRD9a1ZC8KJU3SOAGMzR5XZsXJNbvj3JSZcLLKnv166HtJtimwAsRBwPTfEt7 11dEJz3+70fmmq6Br8ViXp2+q63qYfgC4g+0BEr5YSRZdbtFh0ESYl+hSkV6f1RDXBpp qD3jeLMU/UGIZRjFzqsRS1BvsXj9HKrxEj9QmSaBjPc3X4eTLhyqEllOj5ZfCILkvK0d obDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=rTiZJmJpnBx+QEmTW+5dg14+sfV1C0crqACCRCXWPSI=; b=ZuTwiZR7wkRjzy+OPe1VpfRv+h0Txof3kRG5SFr8LyWwAs+Bk+EnvFP+C5FhoRoa9k 4H8iodfk/RlP2BiPEnqQtVdWOgfbIiFn/L0I5E+fVlS5ajflQjtz79zvskzu4eOOQ5dZ SVCfdqH35cbuX7LAXVOOXSvYOBGCS/8CaRgPAZyheKgx616SAQmLsoWzhlw5lqI6gS/n sCJzt21ykvUTipBN6nn6njs24JWiIRWhpg1h+QWrQB5XTU45AY97+i8WW5Gr56mztumm pBh9b9B7oswHseWRjHatn2sOukiADjj2RPudhXwcq6mYXFEUub/30rv9vrOWlHQus8Fh 1tkQ== X-Gm-Message-State: AOAM533jYoPobsWms3/uwHbBfSGPLsMu44hAm+7Nq0FaijQgaabzv2qd qoHJMxoN2g95K3hz8hpVCr/K0J5jgFQ= X-Google-Smtp-Source: ABdhPJyH5XQIR0IFKVLEgUyiFZy52luM1oiPYmyAV4g11drv1PglVQ7OR2JmOHE5D190Yu0vPLTpWw== X-Received: by 2002:aca:b1c1:: with SMTP id a184mr6155965oif.117.1613581713543; Wed, 17 Feb 2021 09:08:33 -0800 (PST) Received: from Davids-MacBook-Pro.local ([8.48.134.33]) by smtp.googlemail.com with ESMTPSA id r15sm495852otq.77.2021.02.17.09.08.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Feb 2021 09:08:33 -0800 (PST) Subject: Re: null terminating of IFLA_INFO_KIND/IFLA_IFNAME To: =?UTF-8?B?0JzRg9GA0LDQstGM0LXQsiDQkNC70LXQutGB0LDQvdC00YA=?= , netdev@vger.kernel.org References: From: David Ahern Message-ID: <7ef2a1a7-5aa3-3762-85ae-c8e7b77915b3@gmail.com> Date: Wed, 17 Feb 2021 10:08:32 -0700 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.16; rv:78.0) Gecko/20100101 Thunderbird/78.7.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2/17/21 9:06 AM, Муравьев Александр wrote: > Hi > > A noob question that I haven't found an answer. > > Just wanted to clarify a piece of iproute2 code. > > ip/iplink.c: > >> 1058         addattr_l(&req.n, sizeof(req), IFLA_INFO_KIND, type, >> 1059              strlen(type)); > > also ip/iplink.c: > >> 1115         addattr_l(&req.n, sizeof(req), >> 1116               !check_ifname(name) ? IFLA_IFNAME : IFLA_ALT_IFNAME, >> 1117               name, strlen(name) + 1); > My question is why we skip terminating null character for IFLA_INFO_KIND > (the first case) and don't skip it for IFLA_IFNAME (the second case)? I > mean "strlen(type)" and "strlen(name) + 1". > I think it is just different coders at different points in time. Kernel side both use nla_strscpy which handles the string terminator (or missing terminator).