[lwip-users] RE: [lwip] lwIP or uIP

[Peter Bosmans]

Hi Adam,

> -----Oorspronkelijk bericht-----
> Van: address@hidden [mailto:address@hidden Adam Dunkels
> Verzonden: jeudi 11 octobre 2001 8:55
> Aan: address@hidden
> Onderwerp: Re: [lwip] lwIP or uIP
>
>
> Hi Peter!
>
> On Wednesday 10 October 2001 22:25, you wrote:
> > I'm trying to implement uIP on my little motorola 6809 CPU board (10K
> > usable ram for data and code) connected via serial port at my linux home
> > server. I'm so far that i can do a ping.
>
> Great! How much of the code space is used by uIP?
>

Code : 4003 bytes Data : 609 bytes

> > Making a TCP connecting isn't working yet, because of checksum errors.
> > My 6809 GCC compiler doesn't support 32 bit integers, so i've
> to redo the
> > checksum routines.
> > Where can i find the details about the TCP-checksum calculation (IP
> > checksum works great).
> > It goes wrong when the amount of databytes are odd.
>
> There is a bug in the uIP checksum code when compiled for big
> endian systems.
> The bug is quite easily fixed: the code in uip_arch.c that looks
> like this:
>
>   /* add up any odd byte */
>   if(len == 1) {
>     acc += (u16_t)(*(u8_t *)sdata);
>   }
>
> is changed to:
>
>   /* add up any odd byte */
>   if(len == 1) {
>     acc += htons((u16_t)(*(u8_t *)sdata) << 8);
>   }
>

I've found that bug too, but thanks anyway. It makes me more sure.
Now, i can establish a TCP connection. But with a strange problem (or
interpretation). The application on my 6809-board must only echo back the
data i was sendedn to. So, i receive my sended data (Waw, i was happy).
But then the connection came in CLOSE_WAIT on the linux side.
This was because the 6809 board has send a FIN-flag after it had received
the ACK of the sended data. I'm looking why....


> > Now the worst part. I saw that uIP is to obsolete. lwIP will
<snip>
>
> By the way, that's an interesting project (connecting a home controlling
> system with IP and uIP)! Have you made a homepage for your project?

I haven't any time yet to make my homepage. First of all, i will make a
working prototype of my project (as cheap as possible) and then my homepage.
But this will take a while, because i must do this during my free time. (A
few late hours a week, i'm married with children :-)

>
> /adam
> --
> Adam Dunkels <address@hidden>
> http://www.sics.se/~adam
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>

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