Re: [core] [Anima] constrained resources at root for debugging connectivity

Olaf Bergmann <bergmann@tzi.org> Thu, 22 July 2021 09:53 UTC

Return-Path: <bergmann@tzi.org>
X-Original-To: core@ietfa.amsl.com
Delivered-To: core@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 60D4F3A4018; Thu, 22 Jul 2021 02:53:28 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.899
X-Spam-Level:
X-Spam-Status: No, score=-1.899 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id OWerFAeAK0qz; Thu, 22 Jul 2021 02:53:20 -0700 (PDT)
Received: from gabriel-smtp.zfn.uni-bremen.de (gabriel-smtp.zfn.uni-bremen.de [IPv6:2001:638:708:32::15]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id B39CB3A4016; Thu, 22 Jul 2021 02:53:20 -0700 (PDT)
Received: from wangari.tzi.org (p5b36fb81.dip0.t-ipconnect.de [91.54.251.129]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by gabriel-smtp.zfn.uni-bremen.de (Postfix) with ESMTPSA id 4GVnnj0W4qz2xFx; Thu, 22 Jul 2021 11:53:13 +0200 (CEST)
From: Olaf Bergmann <bergmann@tzi.org>
To: Michael Richardson <mcr+ietf@sandelman.ca>
Cc: Esko Dijk <esko.dijk@iotconsultancy.nl>, "anima@ietf.org" <anima@ietf.org>, "core@ietf.org" <core@ietf.org>
References: <AM8P190MB097901225CE72EF7973ADCC4FD139@AM8P190MB0979.EURP190.PROD.OUTLOOK.COM> <AM8P190MB09791181A1D8F74ECDC6F04FFD129@AM8P190MB0979.EURP190.PROD.OUTLOOK.COM> <d2da849f46f57a410d28f47d4ed32f97@bbhmail.nl> <AM8P190MB0979B2CB8DEDB7E9FDCF9C73FDE19@AM8P190MB0979.EURP190.PROD.OUTLOOK.COM> <6b1b6fc38752b6f0598d4289c7cfeb31@bbhmail.nl> <AM8P190MB0979C689144DE6989C5D33E7FDE29@AM8P190MB0979.EURP190.PROD.OUTLOOK.COM> <8c3348a5adb2b2c0d0a4b615cadc75a6@bbhmail.nl> <AM8P190MB0979EC82DA418ECF74440BA9FDE29@AM8P190MB0979.EURP190.PROD.OUTLOOK.COM> <57da5e79b97eeca3967da119a60b0ed6@bbhmail.nl> <AM8P190MB0979EBF594EA31877BFBED5DFDE29@AM8P190MB0979.EURP190.PROD.OUTLOOK.COM> <18975.1626788349@localhost> <AM8P190MB097925B04E575071242002CFFDE39@AM8P190MB0979.EURP190.PROD.OUTLOOK.COM> <25674.1626896178@localhost>
Date: Thu, 22 Jul 2021 11:53:07 +0200
In-Reply-To: <25674.1626896178@localhost> (Michael Richardson's message of "Wed, 21 Jul 2021 15:36:18 -0400")
Message-ID: <87h7gm65fg.fsf@wangari>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)
MIME-Version: 1.0
Content-Type: multipart/signed; boundary="=-=-="; micalg="pgp-sha512"; protocol="application/pgp-signature"
Archived-At: <https://mailarchive.ietf.org/arch/msg/core/ZnNeX0zKV2-5vBcIzHn21fGpxF8>
Subject: Re: [core] [Anima] constrained resources at root for debugging connectivity
X-BeenThere: core@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Constrained RESTful Environments \(CoRE\) Working Group list" <core.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/core>, <mailto:core-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/core/>
List-Post: <mailto:core@ietf.org>
List-Help: <mailto:core-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/core>, <mailto:core-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 22 Jul 2021 09:53:29 -0000

Michael,

On 2021-07-21, Michael Richardson <mcr+ietf@sandelman.ca> wrote:

> Esko Dijk <esko.dijk@iotconsultancy.nl> wrote:
>     > There is already a "CoAP ping" described in RFC 7252 that can be
>     > used. It does not access any resource, just the CoAP server endpoint at
>     > CoAP message layer. As a side effect of this ping your DTLS stack will
>     > set up the connection which is handy.
>
> I recalled that later in the day that CoAP "ping" is not connected to CoAP
> "echo" :-)
> I think that there is also potentially a need for a way to debug possible MTU
> issues.
> Is there a way to use Olaf's "coap-client" to do the ping?

-K does that, see man coap-client (https://libcoap.net/doc/reference/develop/man_coap-client.html):

      -K interval
           Send a ping after interval seconds of inactivity. If
           not specified (or 0), keep-alive is disabled (default).

It would be not difficult to create a dedicated coap-ping, though.

> I don't see an option, and it also doesn't seem to be commonly built
> with DTLS.

It is automatically built with DTLS if you have either GnuTLS, OpenSSL,
Mbed TLS with headers installed (--enable-dtls is default).

Grüße
Olaf