Date: Fri, 18 May 2001 14:15:13 +0400 (MSD) From: "Roman V. Palagin" <romanp@unshadow.net> To: Archie Cobbs <archie@dellroad.org> Cc: <freebsd-hackers@freebsd.org> Subject: Re: How to transfer data from netgraph node to user program? Message-ID: <Pine.SOL.4.33.0105181351210.6629-100000@abyss.unshadow.net> In-Reply-To: <200105172004.f4HK4Jm76648@arch20m.dellroad.org>
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On May 17, at 1:04pm -0700, Archie Cobbs wrote:
> > The question is: how I can initiate smth. like asynchronous reply (so I
> > can get data via NgRecvMsg later in my prgram)? Or I'm going wrong way and
> > should use another scheme for data transfer? Data size ranges from 10Kb to
> > 500Kb.
>
> Whenever you're ready to send the reply, just create one and send it.
It doesn't work. This is fragment of my code:
user-level program:
....
token = NgSendMsg(..., NGM_XXX_SHOW, ...);
/* XXX not reached until ng_xxx_msg() returns */
for(;;) {
...
error = NgRecvMsg(...)
...
}
netgraph node:
/*
* Process control messages
*/
int
ng_xxx_msg()
{
....
case NGM_XXX_SHOW:
error = ng_xxx_show_data()
goto out;
....
out:
....
return (error);
}
/*
* send collected data
*/
int
ng_xxx_show_data()
{
for(;;) {
get_next_data_item();
if (no_more_data)
break;
NG_MKRESPONSE()
error = ng_send_msg()
}
return (error);
}
When size of collected data about 10Kb, all works fine. But when I need to
send 400Kb in reply - oops, ng_xxx_show_data() returns ENOBUFS (I think
because ng_socket receive queue is full, nobody reads from socket). So, I
don't understand how I can transfer large amount of data :-\ Any ideas?
- Roman
---
Any opinions in this posting are my own and not those of my present
or previous employers.
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