Re: Bug with FIONREAD for TCP?

[Richard Gooch]

David S. Miller writes:
>    Date: 	Mon, 10 Apr 2000 00:15:20 -0600
>    From: Richard Gooch <[e-mail]>
> 
>      Hi, all. For at least a month or two I've noticed that FIONREAD
>    yields 1 byte on a freshly closed TCP connection, rather than 0.
> 
>    The server creates a socket, binds to a port and listens and
>    accepts the first connection. It does a select(2) on the FD, and
>    upon an input event, calls ioctl(2) with FIONREAD. This yields 1
>    byte readable. Any attempt to read that byte fails, as it's not
>    really there.
> 
> It's the sequence byte taken up by the initial SYN.  It's probably
> wrong.

Mmm...

> I don't know if other systems report it this way too, do you have a
> way to check this out?

I've been using this technique for nearly 10 years, and FIONREAD has
always yielded 0 bytes readable on close for ConvexOS, SunOS 4.x,
Solaris 2.x, IRIX 5.x and 6.x, AIX 3.x, HP-UX ?.?, UNICOS ?.?, Ultrix,
DEC OSF/1 (aka Digital Unix aka Tru64 Unix aka tomorrow's new name).
Even Linux worked this way, until sometime in the last 4 months, while
I was away (2.3.x series of course).

If you mean: do I have a test programme, then yes. I'll post that if
you want.

				Regards,

					Richard....
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