Re: [lwip-users] netbuf_data() netconnwrite() problem

[address@hidden]

Of course if the incoming netbuf/pbuf says it only holds 10 bytes there 
is no point in changing its length: it doesn't have more. I suggest 
tracing what's on the wire using wireshark/ethereal and comparing that 
with what you receive. Breakpoints in the ethernet driver also help a lot.

Simon


Francois Bouchard wrote:
> Ok, but the incoming netbuf says it's 10 bytes.  I tried your suggestion to
> change length from 10B to 20B  (as u8_t  to u16_t) but it does not help; I
> dont receive the good data.
>
>  if(netbuf_data(inbuf, (void*)&buf, &buflen) == ERR_OK)
>      {
>          netconn_write(conn, buf, buflen, NETCONN_NOCOPY);
>      }
>
> This code works for a string ie. it sends exactly the same thing.  But for
> ushorts I can't manage them.  Maybe I'll stick to strings ... and change the
> client test program.
>
> Thanks
>
> Francois
>
> ----- Original Message -----
> From: <address@hidden>
> To: "Mailing list for lwIP users" <address@hidden>
> Sent: Monday, February 16, 2009 12:22 PM
> Subject: Re: [lwip-users] netbuf_data() netconnwrite() problem
>
>
>   
> > Francois Bouchard wrote:
> >     
> > > Ok, I think that the cast is the good thing to do (I got exemple that
> > > does that).
> > >
> > > But that does'nt fix my problem.  The client application sends 10
> > > unsigned short, then the server is supposed to send back the 10 u16_t
> > > var, but it retransmits half of the data.  The length of the pBuf is
> > > 10; but is it 10 octets?  If so that is why I get half of my data back.
> > >
> > > Hope it's not confusing
> > >       
> > It is, a little. But with the pbuf length you are right: both p->len and
> > p->tot_len are byte counters. When sending 10 ushorts, you have to set
> > the size of data to send to the correct amount.
> >
> > E.g. when sending an array: tcp_write(.., (void*)ushort_array,
> > 10*sizeof(ushort), ...)
> >
> > or when executing 10 individual writes: tcp_write(.., (void*)an_ushort,
> > sizeof(ushort), ...)
> >
> > Simon
> >
> >
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> > http://lists.nongnu.org/mailman/listinfo/lwip-users
> >
> >     
>
>
>
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