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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 B32DCC3A59E for ; Tue, 3 Sep 2019 03:13:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 73AC1217F5 for ; Tue, 3 Sep 2019 03:13:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="UeuFaehL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725955AbfICDNo (ORCPT ); Mon, 2 Sep 2019 23:13:44 -0400 Received: from mail-qk1-f171.google.com ([209.85.222.171]:42816 "EHLO mail-qk1-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725823AbfICDNo (ORCPT ); Mon, 2 Sep 2019 23:13:44 -0400 Received: by mail-qk1-f171.google.com with SMTP id f13so14272802qkm.9 for ; Mon, 02 Sep 2019 20:13:44 -0700 (PDT) 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=vCOtJHCH9cTZCv822fAyW+OPmayoCJ+PCQuotJNQybE=; b=UeuFaehLJlmabYDqViRekCg0Xf+0whuZSTGDfab8u4xlsuc/C3MNm1HOhb5hjdx1/T nNj018jCwzYpSPujmrjTGhwbWL+ih+eFWcP7+MQN54+yOc6FPDvOtHoPI3vbpgJgyt4N ToM4FRJUzT3HOF3k59oelxqCmiINd8myP6VKg4Y7pWgmYqn0vfZpH0UYt+1LjVXffdiE +hFjhhW3owfB+zeLzFm3B52KOSNLf27j9s5KvLGlkl6TQOEM0mMDDA2d4S+Cqnm5Nd/4 lXhaBxXYucKiviODnzb6Wi6z/uD+O7M9gxAS1oidRxZgP/smfka3l52bkxD0qHKNLH3g 7pHw== 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=vCOtJHCH9cTZCv822fAyW+OPmayoCJ+PCQuotJNQybE=; b=brcA7Uu5VRq4dvDqZgCOxrJm1gxI1MWA6nKlnMco7pGaPqThMzP2wNcfcvx4L+Urf1 uoW2r85jvERifajh5yaNMnqY+79UiCsZGr3bCgKXvqE3MRimgkZAbterOh5LWkljgumI yVqTK7HJ5mR1tCj7kw4yOYB9SQcNFd95cDC+BVIki7QjJ1Xv0jWeO+7UBNFdzkXLffAJ lEdr4PiQ4XZD6kF6+RpXto0kjm3p2dXM+OMPsCgo7hNkRAYz5Ti0R9RTFvoZvlNeeYT7 TE8fjfMub0fd17wL7n13dgWeHyXbLMIXlzx4LSHZsL5EHyRRlfQddMSJhEKe7cWASopp q9EA== X-Gm-Message-State: APjAAAU7qdqivls91tGAlsG6eFH8cQxTMGQ61ljhiArpMxnQOplKMPFB FfscTrODZ8RJqRQWQ7LCoEr8vE20 X-Google-Smtp-Source: APXvYqzu5FiNqR2RxE68+7+K9k/xH6tU4k8KNMrKlVJn4tD2O9KvYUHADpUenjgm0HJVpI0bm/vlhQ== X-Received: by 2002:a05:620a:685:: with SMTP id f5mr31168986qkh.238.1567480423270; Mon, 02 Sep 2019 20:13:43 -0700 (PDT) Received: from Davids-MacBook-Pro.local ([2601:282:800:fd80:6da7:da64:698e:698d]) by smtp.googlemail.com with ESMTPSA id k21sm7644455qki.50.2019.09.02.20.13.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Sep 2019 20:13:42 -0700 (PDT) Subject: Re: how to search for the best route from userspace in netlink? To: Dave Taht , Linux Kernel Network Developers References: From: David Ahern Message-ID: <3e8fd488-1bd1-3213-6329-6baf8935a446@gmail.com> Date: Mon, 2 Sep 2019 21:13:40 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 9/2/19 4:07 PM, Dave Taht wrote: > Windows has the "RtmGetMostSpecificDestination" call: > https://docs.microsoft.com/en-us/windows/win32/rras/search-for-the-best-route > > In particular, I wanted to search for the best route, AND pick up the > PMTU from that (if it existed) > for older UDP applications like dnssec[1] and newer ones like QUIC[2]. RTM_GETROUTE with data for the route lookup. See iproute2 code as an example.