[erlang-questions] : sctp_peer_addr_params

Raimo Niskanen <>
Thu Jan 22 11:58:16 CET 2009


On Thu, Jan 22, 2009 at 08:53:51AM +0100, Raimo Niskanen wrote:
> On Wed, Jan 21, 2009 at 07:52:56AM +0100, Mikael Lixenstrand wrote:
> > I'm trying to change the sack delay in gen_sctp
> > 
> >  {ok,Socket} = gen_sctp:open([{ip, ServerIPAddress}, {port, ServerPort}]
> >   ++ [{sctp_peer_addr_params, #sctp_paddrparams{ assoc_id = 0, address =
> > {ServerIPAddress ,ServerPort} ,sackdelay = 400}},
> >   {mode, binary},
> >   {active, false},
> >   {sctp_events,#sctp_event_subscribe{address_event = false,
> > shutdown_event=false}}]),
> > 
> > I tried several approaches but with the same result:
> > 
> > Error in process <0.7100.1> on node '' with exit value:
> > {badarg,[{gen_sctp,open,[[{ip,{10,70,160,17}},{port,3868},{sctp_peer_addr_params,{sctp_paddrparams,0,{{10,70,160,17},3868},200,5,600,400,[]}},{mode,binary},{active,false},{sctp_events,{sctp_event_subscribe,undefined,undefined,false,undefined,undefined...
> > 
> > I'm running R12B-0 on rhel 5.2
> > 
> 
> Congratulations, you have found a bug!
> 
> You have dived down to the untested parts of the SCTP code.
> It is still something we have left to do to write thorough
> test cases for gen_sctp. Unfortunately there are a _lot_
> of options and functionality to test so it is a big task.
> 
> Nevertheless..
> 
> The decoding in the inet driver for #sctp_paddrparams{address={IP,P}}
> is wrong; it does not expect the address family byte that it gets
> and detects a parameter length mismatch.
> 
> I had a small patch yesterday, but I could not set default
> sctp_peer_addr_params for future associations, so I started
> to read the spec, and indeed it should be possible.
> 
> So yesterdays 2 character patch of inet_drv.c now is a patch
> for erts/configure.in, inet_drv.c and prim_inet.erl. I will
> do some more testing and post a patch hopefully during the day.

Here is the patch. Unfortunately it is a minimal path for the
current development branch so it will not be applied cleanly
to R12B-5 or any other released source. But applying it manually
should be no problem for the initiated user.

erts/configure.in: Spelling error `ssh_data' -> `ssf_data'
	To do this manually to its autoconf result erts/configure
	change all occurences of `ssh_data' to `ssf_data' while
	preserving case. I have searched and there are
	no false occurences.

erts/emulator/drivers/common/inet_drv.c:
	Two changes of inet_set_address -> inet_set_faddress.
	A few changes of HAVE_SCTP_* -> HAVE_STRUCT_SCTP_*.
	Use the patch to find the places.

erts/preloaded/src/prim_inet.erl:
	This file has moved in our development branch;
	I think it was in lib/kernerl/src in R12B-5.

With these patches it appears to work. Note that it is the
peers address and port you use in the option! To set it
on future associations you must not specify the peer
address or association id. This is now possible thanks
to the prim_inet.erl patch. Without that patch you
could use address={{0,0,0,0},0} and assoc_id=0.
See http://tools.ietf.org/html/draft-ietf-tsvwg-sctpsocket-13#section-7
just before section 7.1, and 
http://tools.ietf.org/html/draft-ietf-tsvwg-sctpsocket-13#section-7.1.13

In one erlang shell:

Erlang R13A (erts-5.7) [64-bit] [smp:4] [async-threads:0] [kernel-poll:false]

Eshell V5.7  (abort with ^G)
1> gen_sctp:open([{ip,loopback}]).
{ok,#Port<0.444>}
2> {ok,S} = v(-1).
{ok,#Port<0.444>}
3> gen_sctp:listen(S, true).
ok
4> inet:port(S).
{ok,32850}

And then the action in another erlang shell:

Erlang R13A (erts-5.7) [64-bit] [smp:4] [async-threads:0] [kernel-poll:false]

Eshell V5.7  (abort with ^G)
1> rr(inet).
[connect_opts,hostent,listen_opts,sctp_adaptation_event,
 sctp_assoc_change,sctp_assoc_value,sctp_assocparams,
 sctp_event_subscribe,sctp_initmsg,sctp_opts,
 sctp_paddr_change,sctp_paddrinfo,sctp_paddrparams,
 sctp_pdapi_event,sctp_prim,sctp_remote_error,sctp_rtoinfo,
 sctp_send_failed,sctp_setadaptation,sctp_setpeerprim,
 sctp_shutdown_event,sctp_sndrcvinfo,sctp_status,udp_opts]
2> {ok,S} = gen_sctp:open([{sctp_peer_addr_params, #sctp_paddrparams{sackdelay=400,flags=[sackdelay_enable]}}]).
{ok,#Port<0.456>}
3> gen_sctp:connect(S, localhost, 32850, []).
{ok,#sctp_assoc_change{state = comm_up,error = 0,
                       outbound_streams = 10,inbound_streams = 10,
                       assoc_id = 1}}
4> inet:setopts(S, [{sctp_peer_addr_params, #sctp_paddrparams{sackdelay=500,flags=[sackdelay_enable],assoc_id=1,address={loopback,32850}}}]).
ok
5> inet:getopts(S, [sctp_peer_addr_params]).
{ok,[{sctp_peer_addr_params,
         #sctp_paddrparams{
             assoc_id = 0,
             address = {{0,0,0,0},0},
             hbinterval = 30000,pathmaxrxt = 5,pathmtu = 0,
             sackdelay = 400,
             flags = [hb_enable,pmtud_enable,sackdelay_enable]}}]}
6> inet:getopts(S, [{sctp_peer_addr_params, #sctp_paddrparams{assoc_id=1,address={loopback,32850}}}]).
{ok,[{sctp_peer_addr_params,
         #sctp_paddrparams{
             assoc_id = 1,
             address = {{127,0,0,1},32850},
             hbinterval = 30000,pathmaxrxt = 5,pathmtu = 16436,
             sackdelay = 500,
             flags = [hb_enable,pmtud_enable,sackdelay_enable]}}]}


> 
> > Thanks
> 
> > _______________________________________________
> > erlang-questions mailing list
> > 
> > http://www.erlang.org/mailman/listinfo/erlang-questions
> 
> -- 
> 
> / Raimo Niskanen, Erlang/OTP, Ericsson AB
> _______________________________________________
> erlang-questions mailing list
> 
> http://www.erlang.org/mailman/listinfo/erlang-questions

-- 

/ Raimo Niskanen, Erlang/OTP, Ericsson AB
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