comp.os.linux.development.system Google Group

Re: passing file descriptor between processes

n...@vulcan.lan (Nate Eldredge) — Fri, 10 Oct 2008 22:22:01 UT

Aha. Most functions, if they succeed, do not touch errno at all. So
probably it had been set to ENOENT by some function earlier in the
program which failed, and not changed after that.

Re: passing file descriptor between processes

peter_c_...@hotmail.com — Fri, 10 Oct 2008 20:58:48 UT

Thanks, Gil. I'm sorry I hadn't had a chance to reply earlier. I got
it working. fstat showed the fields matching between the two
processes. There was an error in the code that tested error
conditions. Instead of testing for == -1, it tested for != -1. The
return code was 0 so it went into the error handler and printed out

Re: send packet to Linux networking stack

tauno.voi...@invalidiki.fi (Tauno Voipio) — Fri, 10 Oct 2008 19:33:43 UT

The tun and tap drivers could help, as they
are interfaces from network stack link and
packet layers to and from character devices.

Re: send packet to Linux networking stack

postmas...@localhost.localdomain (Bob Hauck) — Fri, 10 Oct 2008 15:56:33 UT

On Fri, 10 Oct 2008 15:18:56 +0200, Rainer Weikusat
Yes, thank you, I get it now. I totally misunderstood the question due
to the fact that I am a complete and utter incompetent and moron. Thank
you for clearing that up.
In addition, I'm a putz and shouldn't be allowed on Usenet without a
minder. My cat is smarter than me, and probably smells better too. If

Re: send packet to Linux networking stack

postmas...@localhost.localdomain (Bob Hauck) — Fri, 10 Oct 2008 15:55:22 UT

On Fri, 10 Oct 2008 14:56:57 +0200 (CEST), Gil Hamilton
It wouldn't. I obviously misunderstood the question. I think it would
have been sufficient to point that out as opposed to supposing I need to
read Wikipedia to understand what a network stack is.

Re: send packet to Linux networking stack

rweiku...@mssgmbh.com (Rainer Weikusat) — Fri, 10 Oct 2008 13:18:56 UT

[...]
The OP wrote that he "used netif_rx call to send those
packet but I am not able to check wehter it reaches to Linux
networking stack."
netif_rx is used by the rx routine of a driver to pass received frames
'upstack' for further processing by 'the networking stack'. There is
exactly no base for your assumption that he intended to send a frame

Re: send packet to Linux networking stack

gil_hamil...@hotmail.com (Gil Hamilton) — Fri, 10 Oct 2008 13:15:15 UT

pkama...@gmail.com wrote in news:08b0cd6f-a285-4af8-bb87-3 871d6767f84
@v30g2000hsa.googlegroups.com:
netif_rx is the traditional way to insert sk_buffs into the stack. So yes
that should work and can be called either directly from an interrupt
handler or from a deferred bottom half routine (such as a tasklet).

FREE SOFTWARE

acadi...@gmail.com (ACADIA) — Fri, 10 Oct 2008 13:00:22 UT

[link]

FREE SOFTWARE

acadi...@gmail.com (ACADIA) — Fri, 10 Oct 2008 13:00:15 UT

[link]

Re: send packet to Linux networking stack

gil_hamil...@hotmail.com (Gil Hamilton) — Fri, 10 Oct 2008 12:56:57 UT

Bob Hauck <postmas...@localhost.localdom ain> wrote in
trying
of
guess.
I'm sorry you didn't like my answer. I wasn't trying to be a jerk.
When you throw misleading info out onto usenet, you should not be
surprised when someone offers to correct it. The OP said:
How would calling dev_queue_xmit as you suggested be helpful in

Re: send packet to Linux networking stack

pkama...@gmail.com — Fri, 10 Oct 2008 05:08:21 UT

On Oct 10, 6:38 am, Bob Hauck <postmas...@localhost.localdom ain>
wrote:
Thanks for all your comments !!!
Yes. I would like to send the packet to the Linux IP stack.
I thought netif_rx api send the skb buffer to the network interface
scheduler and forward to the Linnux IP stack.
As Hamiltion clearly mentioned dev_queue_xmit(skb) api sends out of

Re: send packet to Linux networking stack

postmas...@localhost.localdomain (Bob Hauck) — Fri, 10 Oct 2008 01:38:39 UT

On Thu, 9 Oct 2008 22:40:53 +0200 (CEST), Gil Hamilton
Thanks ever so much for clearing things up for me!

I wasn't clear on what the OP meant. What kind of packet was he trying
to send? He talks of the "networking queue". What does he mean by
that? Does he mean the IP stack, or the send queue of the ethernet

Re: send packet to Linux networking stack

gil_hamil...@hotmail.com (Gil Hamilton) — Thu, 09 Oct 2008 20:40:53 UT

Bob Hauck <postmas...@localhost.localdom ain> wrote in
[snip]
You are confused (or at least your terminology is :-). By doing this,
you were *not* sending a packet "to the networking stack". Instead you
were placing it in queue to be transmitted outbound via your device and
in fact you were actually *bypassing* the stack by doing so.

Re: the difference of kernel config option among different kernel version?

cbf...@mail.usask.ca (Chris Friesen) — Thu, 09 Oct 2008 19:57:03 UT

You need to look at the help text for the kernel config options in the
Kconfig files.
Chris

Re: send packet to Linux networking stack

cbf...@mail.usask.ca (Chris Friesen) — Thu, 09 Oct 2008 19:56:08 UT

netif_rx() is the appropriate API. If your driver is coded properly,
you should be able to use tcpdump() from userspace to listen in on all
packets received on your interface.
Chris