Re: [rtcweb] Possible to lose initial messages sent by reliable, out-of-band negotiated data channels
Taylor Brandstetter <deadbeef@google.com> Tue, 19 June 2018 22:51 UTC
Return-Path: <deadbeef@google.com>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 45D00130FA6 for <rtcweb@ietfa.amsl.com>; Tue, 19 Jun 2018 15:51:50 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -17.509
X-Spam-Level:
X-Spam-Status: No, score=-17.509 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, ENV_AND_HDR_SPF_MATCH=-0.5, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, T_DKIMWL_WL_MED=-0.01, URIBL_BLOCKED=0.001, USER_IN_DEF_DKIM_WL=-7.5, USER_IN_DEF_SPF_WL=-7.5] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=google.com
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 m-nUZd8hcBp4 for <rtcweb@ietfa.amsl.com>; Tue, 19 Jun 2018 15:51:45 -0700 (PDT)
Received: from mail-ua0-x242.google.com (mail-ua0-x242.google.com [IPv6:2607:f8b0:400c:c08::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 6B813130FCD for <rtcweb@ietf.org>; Tue, 19 Jun 2018 15:51:44 -0700 (PDT)
Received: by mail-ua0-x242.google.com with SMTP id k14-v6so904942uao.12 for <rtcweb@ietf.org>; Tue, 19 Jun 2018 15:51:44 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=7VLkSgMwwiJQEjlDgJ+ErRoF0btOVLe23mHb22cIOgE=; b=JQ8ieY/gspWMsffXX9fBqiBGxNPlPf3CBpZGPOCIQkCh79545tKDK7Rb7ug4CiSF4O zXWhTz2hM5pmkGrYuTIOsN/ioc8TiV69ndaM/9go3EsZaC0nimgAUFLesb9yIoVyVaGK NEdcbJL/VXUh0R7s8AqpP/yAwmPtcDxJ0w5EmtLSkqW5eX7+G0wj3LTciRBnSAMW/3ha rAZPbs5bvayd5Phw7dwxi3gZUks7CN8kZK6fVu+nyQdtQC+ITPFW/bae2Z7HihZ8zRBh ZEqCxG2HoLMHdfhfFE09iz7dkAfh+BksjbDSZVI7VK/QSlUYNGVtPk3kMwdQWa9PZPk8 vUtw==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=7VLkSgMwwiJQEjlDgJ+ErRoF0btOVLe23mHb22cIOgE=; b=WyVG5DtSRWY49WGuatGsRBOw0/r+sE6wHiJXd3hDQICVr7BX+lvjrKoDSmq8ukxdr+ 5gMjhhT5sPT27K8de93ZDu4fcq+dn0Go4zl3VOwQcAXJersMYViP9H25KySoT8AOELru G2c3d4jrfmtbq/lEobptEtaS34djAqqDslG0/djVoCBn1EQMoIVHDWhsyx6mtcdB7I3v 3r2NZA190oM3xYrarVdD7rdqODmUSutkLzFXFaSDrCyvSxxmX/6w0BbffrFZqBSrpUSc QDtpJG+JOWg0Xz5U1d17rHO7aSok7Nw6WMIQSAKspJ6pxAO+xixSUwlXjm0PsA7wYyEZ X6GQ==
X-Gm-Message-State: APt69E0CraOrpUF6l/M9hKGoHAHNoKYTXHWwySVbGNX9KvdzpH4M4z1L 0m2Fbvf3+S1nT9nkAoa+cjfYnooibSgQpOVA+OIvtQ==
X-Google-Smtp-Source: ADUXVKJhVQWR5FEbDLr4R7rIv4gKdf8jPjv8x5nRGrkfx9HJYlyVe5avpITW9OQxKs0/0e4tguj9b5lTUWm8X+1jiZw=
X-Received: by 2002:ab0:130a:: with SMTP id g10-v6mr10962563uae.175.1529448703149; Tue, 19 Jun 2018 15:51:43 -0700 (PDT)
MIME-Version: 1.0
Received: by 2002:a1f:9302:0:0:0:0:0 with HTTP; Tue, 19 Jun 2018 15:51:42 -0700 (PDT)
In-Reply-To: <4627e628bbaf4263b478e9abdaa2b7fe@ericsson.com>
References: <CAK35n0bLdXMVOeh+R5EHegMT4+7eP0dWZ+-7Y82VJkTC4wk5QQ@mail.gmail.com> <4C57BFED-4A4D-4B9E-931A-173E1FE493DF@iii.ca> <CAK35n0a6Ua3YOJS1DfdsMDWuk4wW4vWdZfiUJDK8XinSQnb9NQ@mail.gmail.com> <5A43B371-5B53-4066-9C8C-AD64684DB357@iii.ca> <CAOJ7v-2j4Et19h++i8u_DS8tTbe52MkpyW_Ng6-MB2dJm8+aoQ@mail.gmail.com> <9a5be20f-52e9-8ac7-f213-384f29a7bd28@gmail.com> <F3074BA2-7BBF-4545-87AA-1529D1385FD4@westhawk.co.uk> <4627e628bbaf4263b478e9abdaa2b7fe@ericsson.com>
From: Taylor Brandstetter <deadbeef@google.com>
Date: Tue, 19 Jun 2018 15:51:42 -0700
Message-ID: <CAK35n0a-Qzb3JiT-57dfmDJDrscLcYKNnDwra9Qt0UPw5rfA3g@mail.gmail.com>
To: Christer Holmberg <christer.holmberg@ericsson.com>
Cc: T H Panton <thp@westhawk.co.uk>, Lennart Grahl <lennart.grahl@gmail.com>, "rtcweb@ietf.org" <rtcweb@ietf.org>
Content-Type: multipart/alternative; boundary="000000000000a7befd056f06869c"
Archived-At: <https://mailarchive.ietf.org/arch/msg/rtcweb/lr7KUrJnhVz7mvIXYLLfyVc8jFk>
Subject: Re: [rtcweb] Possible to lose initial messages sent by reliable, out-of-band negotiated data channels
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.26
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/rtcweb/>
List-Post: <mailto:rtcweb@ietf.org>
List-Help: <mailto:rtcweb-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 19 Jun 2018 22:51:51 -0000
It looks like we have 2 votes for "silently drop", 1 for "blow up" and 1 for "behave nicely"... Since this behavior is already undefined, "silently drop" would certainly be the easiest; we can just add a note to the W3C spec: https://github.com/w3c/webrtc-pc/pull/1903 On Sat, Jun 16, 2018 at 8:40 AM, Christer Holmberg < christer.holmberg@ericsson.com> wrote: > +1 > > Regards, > > Christer > > -----Original Message----- > From: rtcweb [mailto:rtcweb-bounces@ietf.org] On Behalf Of T H Panton > Sent: 15 June 2018 18:53 > To: Lennart Grahl <lennart.grahl@gmail.com> > Cc: rtcweb@ietf.org > Subject: Re: [rtcweb] Possible to lose initial messages sent by reliable, > out-of-band negotiated data channels > > > With my very old SNMP hat on, I say 1) you silently drop it. > > I'd also say that this indicates that the {negotiated:true, id:0} thing is > a misfeature. > > T. > > > > On 15 Jun 2018, at 17:44, Lennart Grahl <lennart.grahl@gmail.com> wrote: > > > > I would be fine with either Taylor's option 4) or Justin's option 2) > > by raising an explicit error containing a stream ID. In the WebRTC > > spec, we could then resolve this by adding an `error` event to the > > `RTCSctpTransport` interface where the event would contain the stream > > ID a message has been received on. > > > > Cheers > > Lennart > > > > On 15.06.2018 18:28, Justin Uberti wrote: > >> The key question is: what should the browser do if it gets a data > >> channel message on a channel that it doesn't know about? > >> > >> I believe the only realistic options are: > >> 1) eat it (silent failure) > >> 2) explode (noisy but imprecise failure) > >> > >> > >> On Fri, Jun 15, 2018 at 9:18 AM Cullen Jennings <fluffy@iii.ca> wrote: > >> > >>> > >>> Can the browser take care of it from what it knows about setting up > >>> the channel? > >>> > >>> On Jun 13, 2018, at 4:48 PM, Taylor Brandstetter > >>> <deadbeef@google.com> > >>> wrote: > >>> > >>> It sounds like you and Christer are suggesting the same thing: > >>> "don't allow messages to be sent until you're sure the other peer > >>> has a channel to receive them". Except that there's no way for the > >>> WebRTC stack to know that, since these channels are not signaled in > SDP or any in-band message. > >>> > >>> On Wed, Jun 13, 2018 at 1:32 PM, Cullen Jennings <fluffy@iii.ca> > wrote: > >>> > >>>> > >>>> > >>>> On May 31, 2018, at 12:24 PM, Taylor Brandstetter < > >>>> deadbeef=40google.com@dmarc.ietf.org> wrote: > >>>> > >>>> One might expect that a "reliable" data channel is guaranteed to > >>>> be, well, reliable. But in current implementations, the first > >>>> messages may be lost if the application is negotiating the channels > >>>> out-of-band, and creates the receiving channel too late. > >>>> > >>>> Here's a fiddle that demonstrates this (happens with Chrome and > Firefox): > >>>> https://jsfiddle.net/o2m8tp20/ > >>>> > >>>> Normally this isn't an issue, because a typical application would > >>>> create the out-of-band negotiated channels before the first > >>>> offer/answer is complete, and thus before the SCTP association is > >>>> established. Meaning that by the time a data channel is "open", > >>>> it's guaranteed that the other peer has a corresponding channel. > >>>> > >>>> But if for whatever reason, an application creates a data channel > >>>> *after* the SCTP association is established, then it will instantly > >>>> be "open" as soon as it's created. If a message is sent at this > >>>> point, and it's received by the other peer before it's created its > >>>> corresponding data channel, then the message will just be discarded. > >>>> > >>>> So, how should we deal with this? Some possibilities: > >>>> > >>>> 1. Say "this is expected behavior" and document it better, breaking > >>>> the reliability promise. > >>>> 2. Run the closing procedure if a message is received on a stream > >>>> before a data channel is ready to receive it. > >>>> 3. Don't even allow an out-of-band negotiated channel to be created > >>>> after the SCTP association is established. > >>>> 4. Buffer these messages for up to X seconds (or up to X bytes), to > >>>> be delivered to the data channel once it's created. Run the closing > >>>> procedure if X is exceeded. > >>>> > >>>> I'd vote for #2. Adding additional buffering logic seems like > >>>> overkill if this isn't a use case we really intended to support. > >>>> > >>>> > >>>> I lean toward something that just did not allow the out-of-band > >>>> channel negotiation be used until it was set up. > >>>> > >>>> But whatever we do, not option 1 > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>>> > >>> > >>> _______________________________________________ > >>> rtcweb mailing list > >>> rtcweb@ietf.org > >>> https://www.ietf.org/mailman/listinfo/rtcweb > >>> > >> > >> > >> > >> _______________________________________________ > >> rtcweb mailing list > >> rtcweb@ietf.org > >> https://www.ietf.org/mailman/listinfo/rtcweb > >> > > > > > > _______________________________________________ > > rtcweb mailing list > > rtcweb@ietf.org > > https://www.ietf.org/mailman/listinfo/rtcweb > > _______________________________________________ > rtcweb mailing list > rtcweb@ietf.org > https://www.ietf.org/mailman/listinfo/rtcweb > > _______________________________________________ > rtcweb mailing list > rtcweb@ietf.org > https://www.ietf.org/mailman/listinfo/rtcweb >
- Re: [rtcweb] Possible to lose initial messages se… Justin Uberti
- Re: [rtcweb] Possible to lose initial messages se… Taylor Brandstetter
- Re: [rtcweb] Possible to lose initial messages se… Christer Holmberg
- Re: [rtcweb] Possible to lose initial messages se… Justin Uberti
- Re: [rtcweb] Possible to lose initial messages se… T H Panton
- [rtcweb] Possible to lose initial messages sent b… Lennart Grahl
- Re: [rtcweb] Possible to lose initial messages se… Justin Uberti
- Re: [rtcweb] Possible to lose initial messages se… Cullen Jennings
- Re: [rtcweb] Possible to lose initial messages se… Christer Holmberg
- Re: [rtcweb] Possible to lose initial messages se… Taylor Brandstetter
- Re: [rtcweb] Possible to lose initial messages se… Christer Holmberg
- Re: [rtcweb] Possible to lose initial messages se… Taylor Brandstetter
- Re: [rtcweb] Possible to lose initial messages se… Cullen Jennings
- [rtcweb] Possible to lose initial messages sent b… Taylor Brandstetter
- Re: [rtcweb] Possible to lose initial messages se… Christer Holmberg
- Re: [rtcweb] Possible to lose initial messages se… Taylor Brandstetter
- Re: [rtcweb] Possible to lose initial messages se… Lennart Grahl
- Re: [rtcweb] Possible to lose initial messages se… Justin Uberti
- Re: [rtcweb] Possible to lose initial messages se… Christer Holmberg