Re: Question on sending data over UDP endpoints
Re: Question on sending data over UDP endpoints
- Subject: Re: Question on sending data over UDP endpoints
- From: Justin Walker <email@hidden>
- Date: Thu, 1 Jul 2004 12:44:08 -0700
On Jun 30, 2004, at 23:29, Igor garnov wrote:
Hi Justin and thanks very much for your early reply.
I understand very well that UDP is NOT reliable. However, I experience
the
following situation with my application:
I send a UDP datagram, and immediately install an OT timer, which will
fire
in 5 seconds.
But before this timer actually fires, I receive an ICMP message of
type 3
(Destination unreachable) and code 0 (Network unreachable error). I
strongly suspect that this message has something to do with the data I
have
sent, because there is really nothing else I do, except send this UDP
packet.
The ICMP message may have enough of a packet in it to determine that it
is one that you sent.
After 5 seconds my timer fires and I call OTCloseProvider on the
endpooint,
after which my application freezes.
Hmmm...here, you need an expert on OT, which I'm not.
Should I call OTRcvUDErr before calling OTCloseProvider?
What should I do with the ICMP message apparently pertaining to this
endpoint, which I have already read? Maybe, I should peek at this ICMP
data
without actually reading it into my buffer? Will this ensure that a
higher-level protocol will receive it and take appropriate action (like
calling my notifier routine with T_UDERR code)?
I can't say anything about the proper sequence of OT calls to make.
However, I think it's safe to say that there is no "higher-level
protocol" code that will take any action unless that code is from your
app, and you wrote it to do so.
I also can't imagine that the read/peek distinction will affect things,
but I have been wrong before :-}.
Sorry I can't offer specific suggestions. It may take waiting for the
dust to settle at WWDC before someone with the background to answer can
find the time.
Regards,
Justin
--
Justin C. Walker, Curmudgeon-At-Large *
Institute for General Semantics | If you're not confused,
| You're not paying attention
*--------------------------------------*-------------------------------*
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