[REBOL] Re: UDP Multicast to TCP
From: compkarori:gma:il at: 19-Nov-2009 16:08
open/binary ?
On Fri, Nov 20, 2009 at 6:42 AM, Leon Meyer <lmeyer-bltech.co.za> wrote:
> =A0Hi
>
> Although the TCPtoMulticast and MulticastToUDP applications are working, we
> have picked up an small problem.
>
> The Payload size of the UDP output packets after the conversion does not
> seem to be exactly the same as the incoming TCP Payload size (always a
> couple of bytes extra). The larger the incoming TCP payload size, the more
> bytes seem to be added to the output UDP payload. We have confirmed this
> using Windump (windows version of tcpdump).
>
> For example, =A0a 16 bytes TCP payload becomes a 17 bytes UDP payload
> A 771 bytes payload becomes a 778 UDP payload. Does anyone have any idea
> what could be causing the additional bytes in the UDP payload? Here is the
> TCPtoUDP script:
>
> REBOL[Title: "Port 4550"]
>
> listen: open/no-wait tcp://:4550
> waitports: [listen]
>
> odata: open udp://239.2.0.80:6550 =A0 =A0 =A0; udp broadcast port
> set-modes odata [multicast-ttl: 10]
> set-modes odata [multicast-interface: 192.168.20.23]
>
> =A0 =A0forever [
> =A0 =A0 =A0 =A0port: wait waitports
> =A0 =A0 =A0 =A0either same? port listen [
> =A0 =A0 =A0 =A0 =A0 =A0active-port: first listen
> =A0 =A0 =A0 =A0 =A0 =A0append waitports active-port
> =A0 =A0 =A0 =A0] [
> =A0 =A0 =A0 =A0 =A0 =A0incoming-from-remote: copy port
> =A0 =A0 =A0 =A0 =A0 =A0either incoming-from-remote [
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 insert odata incoming-from-remote
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 ;print incoming-from-remote
> =A0 =A0 =A0 =A0 =A0 =A0] [
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0remove find waitports port
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0close port
> =A0 =A0 =A0 =A0 =A0 =A0]
> =A0 =A0 =A0 =A0]
> =A0 =A0]
>
> Thank you
> Leon
>
> PS - I have removed the "read requests" from my email now- sorry if it
> caused any problems yesterday.
>
> -----Original Message-----
> From: rebol-bounce-rebol.com [mailto:rebol-bounce-rebol.com] On Behalf Of
> Gabriele Santilli
> Sent: Wednesday, November 18, 2009 12:50 PM
> To: rebolist-rebol.com
> Subject: [REBOL] Re: UDP Multicast to TCP
>
> On Wed, Nov 18, 2009 at 11:42 AM, Petr Krenzelok <petr.krenzelok-seznam.cz>
> wrote:
>
>> I hope I am not wrong here, but you should know, that in R2, you
>> basically can work in two modes - blocking (synchronous), and non
>> blocking. When you open your port without /no-wait refinement, then
>> 'copy action on port blocks. It is your case, as you issue "copy
>> multicast", where multicast is opened in blocking mode. In this mode,
>> copy waits for other side to close the connection. That might be the
>> reason why your code "halts". Try simple example:
>
> Mmm, Petr, actually, he's only copying on the UDP port after a wait, so I
> don't think this would be a problem. Besides, it seems to me that /no-wait
> does not work on UDP listen ports...
>
>> Console1:
>> ---------
>> server: open tcp://:9005
>
> Your assumption that UDP behaves just like TCP is so very wrong. ;)
>
> Regards,
> =A0 =A0Gabriele.
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--
Graham Chiu
http://www.synapsedirect.com
Synapse - the use from anywhere EMR.
