Re: [lwip-users] udp

[David Haas]

Hi Nic,

Are you using UDP with sockets? I would not be planning on changing the 
way the raw API works in any way. However, please see my previous 
message. I really think this is a bug. The data buffer sent with 
sendto() has to hang around until it gets released from the ARP queue. 
There is no way to know when this happens. If you are personally using 
UDP with sockets, how are you handling this in your code?

David.


NGB wrote:

> Please no
>
> UDP is supposed to be low latency, we don't want to waste CPU time copying 
> stuff into buffers.
>
> Thanks
>
> Nic
>
> Quoting David Haas <address@hidden>:
>
>  
>
> > Hi all,
> >
> > I am using UDP for the first time with lwip and I am running into a few 
> > issues.
> >
> > Numero Uno: The sockets interface for TCP copies data when you call 
> > send() into the socket and the application can safely dispose of the 
> > buffer afterwards. However for UDP, the sockets interface passes the 
> > data through without copying it. I do believe that UDP should not 
> > default to this kind of operation. After all, how do you know when you 
> > can free the application buffer? Especially if your packet winds up on 
> > the ARP queue.
> >
> > Would anyone have any objection if I "fix" this for the sockets 
> > interface to copy the data into a UDP socket when sendto() is called?
> >
> > David.
> >
> >
> >
> >
> > _______________________________________________
> > lwip-users mailing list
> > address@hidden
> > http://mail.nongnu.org/mailman/listinfo/lwip-users
> >
> >    
>
>
>
>
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