[ECOS] max IP packet size = 9216 B. Why?

[Jürgen Lambrecht]

Hi,

It is a implicit limitation of eCos: to limit the amount of RAM needed, 
the maximum IP packet size is 9kB.
This is hardcoded in the eCos code, so I changed it there.
I don't remember where, but when I find it, I will mail you again.

Kind regards,
Jürgen

On 05/04/2017 02:55 AM, lawshere@gmail.com wrote:
> is there any patch for it,
> no matter how i set SNDBUF, the problem is still,
> it seems the maximum accessable size for one udp packet is the same as 
> MTU.
>
> 在 2007年6月12日星期二 UTC+8下午11:49:30，Jürgen Lambrecht写道：
>
>     Hello,
>
>     I found out that the maximum IP packet size = 9216 B (0x2400).
>     I implemented an echo program, both udp and tcp.
>     My ecos applic can receive more that 9216B, but not send back more
>     than
>     that.
>
>     Has anybody a clue how to solve this?
>     I need to support the maximum IP packet size of 65535 B
>     (IP_MAXPACKET).
>     I don't know if this is a bug in ecos, or a (hidden?) limitation
>     of an
>     embedded OS.
>
>     Thanks,
>     Juergen Lambrecht
>
>     P.S.:
>     I'm busy tracing this back in the source
>     This comes from the socket that is allocated statically in
>     /io/fileio/.../fd.cxx and socket is part of a cyg_file (cyg_file is
>     defined by file in file.h). In cyg_file there is a member f_data,
>     which
>     is the socket.
>     I'm continuing my search in the code at this point....
>
>     -- 
>     Jürgen Lambrecht
>     R&D Engineer
>     Televic Transport Systems
>     http://www.televic.com
>     Televic NV / SA (main office)
>     Leo Bekaertlaan 1
>     B-8870 Izegem
>     Tel: +32 (0)51 303045
>     Fax: +32 (0)51 310670
>
>
>     -- 
>     Before posting, please read the FAQ:
>     http://ecos.sourceware.org/fom/ecos
>     <http://ecos.sourceware.org/fom/ecos>
>     and search the list archive:
>     http://ecos.sourceware.org/ml/ecos-discuss
>     <http://ecos.sourceware.org/ml/ecos-discuss>
>


-- 
Jürgen Lambrecht
R&D Associate
Mobile: +32 499 644 531
Twitter: JGRLambrecht
Tel: +32 (0)51 303045    Fax: +32 (0)51 310670
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Televic Rail NV - Leo Bekaertlaan 1 - 8870 Izegem - Belgium
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