Re: inetutils 1.5 / ftpd problem: 426 Data connection: No buffer space available.

[Charles Wilson <cygwin at cwilson dot fastmail dot fm>]

Corinna Vinschen wrote:
> This code only exists in 1.7.  The only way to get ENOBUFS in 1.5.x is
> when Winsock emits it.  I see two possible reasons.  One is a
> third-party firewall software which interacts badly with ftpd on the
> machine with the ENOBUFS problem, the other is ftpd itself.  Does ftpd
> from 1.5 try to write the 215 Megs in one single write call, by any
> chance?

Why, yes, yes it does. But only if #HAVE_MMAP; otherwise it's a little 
more sane and uses BUFSIZ from stdio.h; 1024.

>  We had this discussion lately and I added a stop-gap measure
> into 1.7 so that no write to the net writes more than 64K in one go.
> The problem is that Winsock unintelligibly tries to create a temporary
> internal buffer the size of the write buffer, regardless of its size.
> Naturally that can fail, and if it does, you get the error code
> WSAENOBUFS.  The only way around that for 1.5 is to split network writes
> to smaller chunks.  Doing that is much faster on Windows, too, btw.

Yeah, I'll code that up for 1.5-4.  Should I stick with BUFSIZ == 1024, 
or when MMAP use something a little bigger, say 32k?

--
Chuck

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