How much is available for reading on the socket?

How much is available for reading on the socket?

[Łeandro Sales]

Hi,
 using "ioctl (socket, FIONREAD, &readsize)" I can get how much is
available to read from the socket using TCP. Is there a equivalent
option for DCCP? I used this with DCCP and I got:

ioctl failed: invalid argument

Leandro.

Re: How much is available for reading on the socket?

[Tommi Saviranta]

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On Sun, Oct 21, 2007 at 23:00:38 -0300, Łeandro Sales wrote:
> using "ioctl (socket, FIONREAD, &readsize)" I can get how much is
> available to read from the socket using TCP. Is there a equivalent
> option for DCCP?

Looks like dccp_ioctl() happily returns -ENOIOCTLCMD (for now). If you
have IO and memory to waste, you can always recv(..., MSG_PEEK) to work
around this.

Re: How much is available for reading on the socket?

[Gerrit Renker]

| > using "ioctl (socket, FIONREAD, &readsize)" I can get how much is
| > available to read from the socket using TCP. Is there a equivalent
| > option for DCCP?
| 
| Looks like dccp_ioctl() happily returns -ENOIOCTLCMD (for now). If you
| have IO and memory to waste, you can always recv(..., MSG_PEEK) to work
| around this.
| 
Arnaldo wrote a patch which realises SIOCINQ (it is in 2.6.24-rc1/2).

Re: How much is available for reading on the socket?

[Tommi Saviranta]

On Fri, Nov 09, 2007 at 13:51:27 +0000, Gerrit Renker wrote:
> Arnaldo wrote a patch which realises SIOCINQ (it is in 2.6.24-rc1/2).

No, not one of these days again... Yes, I took a brief look at the patch
and its brief follow up. I was going through my inbox, including all the
mails I have postponed to deal with later, and spotted this one,
completely forgetting it's no longer relevant.

Sorry for the spam (like this email would make things any better).

Re: How much is available for reading on the socket?

[Arnaldo Carvalho de Melo]

Em Fri, Nov 09, 2007 at 01:51:27PM +0000, Gerrit Renker escreveu:
> | > using "ioctl (socket, FIONREAD, &readsize)" I can get how much is
> | > available to read from the socket using TCP. Is there a equivalent
> | > option for DCCP?
> | 
> | Looks like dccp_ioctl() happily returns -ENOIOCTLCMD (for now). If you
> | have IO and memory to waste, you can always recv(..., MSG_PEEK) to work
> | around this.
> | 
> Arnaldo wrote a patch which realises SIOCINQ (it is in 2.6.24-rc1/2).

And, on Linux:

include/linux/sockios.h

/* Linux-specific socket ioctls */
#define SIOCINQ         FIONREAD

- Arnaldo

Re: How much is available for reading on the socket?

[Łeandro Sales]

2007/11/9, Arnaldo Carvalho de Melo <acme@redhat.com>:
> Em Fri, Nov 09, 2007 at 01:51:27PM +0000, Gerrit Renker escreveu:
> > | > using "ioctl (socket, FIONREAD, &readsize)" I can get how much is
> > | > available to read from the socket using TCP. Is there a equivalent
> > | > option for DCCP?
> > |
> > | Looks like dccp_ioctl() happily returns -ENOIOCTLCMD (for now). If you
> > | have IO and memory to waste, you can always recv(..., MSG_PEEK) to work
> > | around this.
> > |
> > Arnaldo wrote a patch which realises SIOCINQ (it is in 2.6.24-rc1/2).
>
> And, on Linux:
>
> include/linux/sockios.h
>
> /* Linux-specific socket ioctls */
> #define SIOCINQ         FIONREAD
>
> - Arnaldo
>

And I'm using this on the gstreamer plugin and it is working ok.

Leandro.

Re: How much is available for reading on the socket?

[Gerrit Renker]

| > > Arnaldo wrote a patch which realises SIOCINQ (it is in 2.6.24-rc1/2).
| >
| > And, on Linux:
| >
| > include/linux/sockios.h
| >
| > /* Linux-specific socket ioctls */
| > #define SIOCINQ         FIONREAD
| >
| > - Arnaldo
| >
| 
| And I'm using this on the gstreamer plugin and it is working ok.
| 
So that other people not have to make the same mistake as me and mistake
SIOCINQ and FIONREAD, I have patched an update to
Documentation/networking/dccp.tx (next email).

Have you got the sources available for the DCCP plugin: it would be 
interesting to see how it is used. After the handshake ioctl(FIONREAD)
returns 0 for a while, and same after last read.

If done intelligently, this could solve the End-of-File problem reported 
earlier by Remi Denis-Courmont.

Re: How much is available for reading on the socket?

[Gerrit Renker]

[DCCP]: Update documentation on ioctls

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
---
 Documentation/networking/dccp.txt |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/Documentation/networking/dccp.txt
+++ b/Documentation/networking/dccp.txt
@@ -161,6 +161,12 @@ sync_ratelimit = 125 ms
 	sequence-invalid packets on the same socket (RFC 4340, 7.5.4). The unit
 	of this parameter is milliseconds; a value of 0 disables rate-limiting.
 
+IOCTLS
+===
+FIONREAD
+	Works as in udp(7): returns in the `int' argument pointer the size of
+	the next pending datagram in bytes, or 0 when no datagram is pending.
+
 Notes
 == 

Re: How much is available for reading on the socket?

[Ian McDonald]

On 11/15/07, Gerrit Renker <gerrit@erg.abdn.ac.uk> wrote:
> [DCCP]: Update documentation on ioctls
>
> Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>

Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz>