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Hej Per!</div>
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So an ssh:setopts(SshConnection, InetOptions) and an ssh:getopts similar to two functions in inet would solve the problem?</div>
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/Hans<br>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>Från:</b> erlang-questions <erlang-questions-bounces@erlang.org> för Per Hedeland <per@hedeland.org><br>
<b>Skickat:</b> den 18 februari 2020 14:08<br>
<b>Till:</b> erlang-questions@erlang.org <erlang-questions@erlang.org><br>
<b>Ämne:</b> Re: Sv: Setting Dscp (tos, QoS) for ssh sockets</font>
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<div class="PlainText">On 2020-02-18 12:58, Hans Nilsson R wrote:<br>
> It is both possible and documented to give the gen_tcp:connect_options() in a call to ssh:connect.<br>
><br>
> See<br>
> <a href="https://protect2.fireeye.com/v1/url?k=6eb80c5a-326c0004-6eb84cc1-8691959ed9b7-0b75d45a9ce427c8&q=1&e=1e4ceab2-3f29-4036-8a8c-cc4774d3d176&u=https%3A%2F%2Ferlang.org%2Fdoc%2Fman%2Fssh.html%23type-client_option">
https://protect2.fireeye.com/v1/url?k=6eb80c5a-326c0004-6eb84cc1-8691959ed9b7-0b75d45a9ce427c8&q=1&e=1e4ceab2-3f29-4036-8a8c-cc4774d3d176&u=https%3A%2F%2Ferlang.org%2Fdoc%2Fman%2Fssh.html%23type-client_option</a><br>
><br>
> where second from last is a link to<br>
> <a href="https://protect2.fireeye.com/v1/url?k=a1d9ada1-fd0da1ff-a1d9ed3a-8691959ed9b7-d0da1a82086ec97e&q=1&e=1e4ceab2-3f29-4036-8a8c-cc4774d3d176&u=https%3A%2F%2Ferlang.org%2Fdoc%2Fman%2Fgen_tcp.html%23type-connect_option">
https://protect2.fireeye.com/v1/url?k=a1d9ada1-fd0da1ff-a1d9ed3a-8691959ed9b7-d0da1a82086ec97e&q=1&e=1e4ceab2-3f29-4036-8a8c-cc4774d3d176&u=https%3A%2F%2Ferlang.org%2Fdoc%2Fman%2Fgen_tcp.html%23type-connect_option</a><br>
<br>
Sorry, don't know how I missed that - too much going back and forth<br>
between the "textual" man pages for ssh and gen_tcp, perhaps... And<br>
indeed gen_tcp:listen_option() is also listed for daemon_option(). So<br>
there is no problem whatsoever with setting DSCP at the start of a<br>
connection.<br>
<br>
Is there also some "clean" way within ssh to address Christofer's and<br>
Dmytro's original question (below), which I managed to obscure - i.e.<br>
setting DSCP for an already established connection? (Which is needed<br>
for an implementation of RFC 8639.)<br>
<br>
--Per<br>
<br>
> Let's try:<br>
><br>
> Eshell V10.6.4 (abort with ^G)<br>
> 1> ssh:start().<br>
> ok<br>
> 2> dbg:start().<br>
> {ok,<0.92.0>}<br>
> 3> dbg:tracer().<br>
> {ok,<0.92.0>}<br>
> 4> dbg:p(all,c).<br>
> {ok,[{matched,nonode@nohost,46}]}<br>
> 5> dbg:tp(gen_tcp,connect,x).<br>
> {ok,[{matched,nonode@nohost,2},{saved,x}]}<br>
> 6><br>
> 6> ssh:connect(loopback, 22, [{nodelay,true}, {tos,14}, {raw,1,2,<<3>>}]).<br>
> (<0.80.0>) call gen_tcp:connect({127,0,0,1},22,[{active,false},{raw,1,2,<<3>>},{tos,14},{nodelay,true}],infinity)<br>
> (<0.80.0>) returned from gen_tcp:connect/4 -> {ok,#Port<0.6>}<br>
> {ok,<0.99.0>}<br>
> 7><br>
><br>
> The gen_tcp options in 6> are really passed down to gen_tcp:connect.<br>
><br>
> /Hans<br>
><br>
> --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------<br>
> *Från:* erlang-questions <erlang-questions-bounces@erlang.org> för Per Hedeland <per@hedeland.org><br>
> *Skickat:* den 17 februari 2020 20:44<br>
> *Till:* erlang-questions@erlang.org <erlang-questions@erlang.org><br>
> *Ämne:* Re: Setting Dscp (tos, QoS) for ssh sockets<br>
><br>
> On 2020-02-17 16:03, Per Hedeland wrote:<br>
> > On 2020-02-17 11:22, Dmytro Lytovchenko wrote:<br>
> > > As we discussed with you before, there are two options right now:<br>
> > ><br>
> > > 1. From SSH connection handler, using sys module, request its state (private #data{} record) which contains the socket in its 9th field.<br>
> > > 2. (Christofer's idea) to replace the socket transport module using undocumented option {transport, {_, Module, _}}<br>
> > ><br>
> > > Maybe someone sees other ways to do it?<br>
> ><br>
> > Why would you need to use inet:setopts/2 specifically? Changing DSCP<br>
> > on the fly is probably not meaningful in general, and from what I know<br>
> > about your application, not required there (but maybe I'm wrong about<br>
> > that).<br>
><br>
> I learned off-list that this requirement comes from RFC 8639, where a<br>
> NETCONF client/subscriber can request that the server uses a specific<br>
> DSCP value in the "establish-subscription" RPC (which is sent in an<br>
> already established session a.k.a. SSH channel). Surely OTP ssh should<br>
> support this in a "nice/clean" way...?<br>
><br>
> > IMHO it would be reasonable to allow most/all options that can be<br>
> > given to gen_tcp:connect/3,4 and gen_tcp:listen/2 (which both have<br>
> > 'tos' as option), respectively, also for ssh:connect/2,3,4 and<br>
> > ssh:daemon/2,3 - maybe it is allowed, but if so not documented, as far<br>
> > as I can see.<br>
> ><br>
> > Alternatively you can at least for ssh:connect/2,3 apparently pass an<br>
> > already connected socket from gen_tcp:connect(), where you can pass<br>
> > 'tos' to the latter. It seems the socket that can be passed to<br>
> > ssh:daemon/2,3 should be from gen_tcp:accept() - it would seem more<br>
> > natural to me to pass a "listen socket" from gen_tcp:listen() (which<br>
> > can be passed 'tos'), but I guess you can do the accept-loop outside<br>
> > ssh and use inet:setopts/2 on the socket from gen_tcp:accept() before<br>
> > passing it to ssh:daemon/2,3.<br>
><br>
> For this alternative, the way to go would rather be to pass the 'tos'<br>
> option to gen_tcp:listen(), and have it be "inherited" by the sockets<br>
> returned from gen_tcp:accept() - i.e. no need for inet:setopts/2<br>
> there. But of course neither alternative supports changing the DSCP<br>
> value for an already established connection.<br>
><br>
> --Per<br>
><br>
> > > On Mon, 17 Feb 2020 at 11:12, Christofer Tornkvist (ctornkvi) <ctornkvi@cisco.com <<a href="mailto:ctornkvi@cisco.com">mailto:ctornkvi@cisco.com</a>>> wrote:<br>
> > ><br>
> > > Hi,<br>
> > ><br>
> > > I would like to set the quality of service flag Dscp of the Tos field in the IP packet<br>
> > > of an Ssh socket with the function inet:setopts(Socket, [{tos, Dscp}]).<br>
> > ><br>
> > > It should be possible to set the Dscp per IP packet sent.<br>
> > ><br>
> > > How do I get hold of the Ssh socket down in my Ssh channel module ?<br>
> > ><br>
> > ><br>
> > > Regards<br>
> > > /Christofer<br>
> > ><br>
> > ><br>
> > ><br>
><br>
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