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Re: max IP packet size = 9216 B. Why?
- From: Jürgen Lambrecht <J dot Lambrecht at televic dot com>
- To: lawshere at gmail dot com, "osdeve.mirror.rtos.ecos-discuss" <osdeve_mirror_rtos_ecos-discuss at googlegroups dot com>
- Cc: ecos-discuss at ecos dot sourceware dot org, jurgen dot lambrecht at scarlet dot be
- Date: Tue, 20 Jun 2017 12:29:01 +0200
- Subject: Re: max IP packet size = 9216 B. Why?
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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
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Televic Transport Systems
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