[e2e] overlay over TCP

[Randall Stewart]

Joe Touch wrote:
> 
> 
> Randall Stewart wrote:
> 
>> Joe Touch wrote:
>>
>>>> Nope.. you DON'T need to rewrite NAT to do SCTP.. its a simple
>>>> set of changes..
>>>
>>>
>>>
>>>
>>> Let's see. You rewrite your NAT to understand a new protocol number, 
>>> where the ports might be, and how to rewrite DATA IN ITS BODY. How do 
>>> you accomplish that without "doing SCTP"?
>>>
>>
>> Would you like me to send you the code? I have it
>> done for FreeBSD.. have not went through extensive testing
>> yet since I ran out of time and still have the f/w side
>> to complete.
>>
>> As to "doing SCTP" NAT's don't do TCP.. they know about
>> it.. where the ports are, what the c-sum is etc.
> 
> 
> And where the data is, which for TCP and DCCP isn't as tricky ;-)

There was no trick to it... one does not have to
know where the data is since the header is
just like TCP, just like UDP, just like DCCP.

And all data (data and control) start after the
header.. no different than TCP.. except for one
minor rinkle.. I don't have to do the bit with
psuedo headers...

I have implemented this .. its not hard it is almost
a ver-batim clone of the TCP code.. except it was
a few lines less :-D



> 
>> Same for UDP and of course the same thing is needed
>> for SCTP. You have to understand a "SYN" or an "INIT"
>> but it is not as complex as you make out.. no more
>> complex than having a NAT do TCP...
> 
> 
> NATs translate data _inside_ the packets too; that's where 'knowing 
> SCTP' is substantially more complex.

FTP, last I checked, does not run over SCTP.. and even
if it did it would not be that tough to find the addresses
etc... no different than knowing the data format of
any other protocol... including TCP..

R


-- 
Randall Stewart
803-345-0369 <or> 815-342-5222(cell)