Re: SCTP API draft (was Re: New "IP Version 6 AddressingArchitecture" draft)

[La Monte Henry Piggy Yarroll]

Hideaki YOSHIFUJI (=?iso-2022-jp?B?GyRCNUhGIzFRTEAbKEI=?=) writes:
>In article <[EMAIL PROTECTED]> (at Thu, 27 Jul 2000 16:28:48 
>-0500), "La Monte Henry Piggy Yarroll" <[EMAIL PROTECTED]> says:
>
>> >> the v6 application could do this more simply by binding to the v4
>> >> address (be it wildcard or not) in addition to any others.
>> >
>> >We cannot do this with Linux.
>> 
>> I have not gotten into the v6 portions of the networking code, but
>> what is the constraint?
>
>Ipv6 tcp layer and ipv4 tcp layer are shared.
>You cannot bind a ipv4 socket to a port already bound to ipv6 socket.
>You cannot bind a ipv6 socket to a port already bound to ipv4 socket.
>
>If you want to provide a service to ipv6 and ipv4 client through single 
>local port, you must create an ipv6 scoket and bind to that port;
>ipv4 clients are serviced by ipv6 scoket through ipv4-mapped addresses.
>
>We may be able to  provide a new socket option that disables ipv4-mapped 
>feature, but I wonder application might abuse; create ipv6 socket, set 
>that sockopt and create ipv4 socket... then Linux cannot provide a service 
>to ipv4 clinets. please note this...

This is actually the sematics which I advocate.  I assume I can still
bind separately to single addresses?

Our proposal for the SCTP is to allow you to bind to arbitrary subsets
of addresses.  The semantics of such an operation for SCTP are
slightly different for SCTP--each association on the transmission
endpoint will use ALL the addresses in the binding.  TCP semantics
call for connections coming in on ANY of the bound addresses.
-- 
Put no trust in extortion,              La Monte Henry Piggy Yarroll
set no vain hope in plunder;            NIC Handle LY
if riches increase,
do not set your heart upon them.
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