Re: Is the linux networking code broken?

Re: Is the linux networking code broken?

[Alex Riesen]

On Fri, May 31, 2002 at 02:47:21AM -0500, Ed Carp wrote:
> On Fri, 31 May 2002, Alex Riesen wrote:
> 
> > Neither of them. How do you think the things are working here? 8-)
> > rsync, wget, apache, a whole lot other programs transfer megabytes.
> 
> Most of them use short writes.  Here's the source I'm using...

Most of them are the biggest possible writes.

~/compile/ercftp ./sender localhost ../nfs-kaboom.c
Using 2048 byte packets
Connecting to localhost
Resolved, opening TCP socket
Doing connect
Connected, waiting for OK...
Waiting for OK...
Sending ../nfs-kaboom.c
... a while
Waiting for ack...
caught signal 14!


~/compile/ercftp ./receiver 
Getting TCP socket
Doing bind
Doing listen
Accepting connection
Writing 23987 to ../nfs-kaboom.c
... another while

caught signal 14! flen=23987, inlen=0, pos=0, packets=12, packet.seqno=0


Neither of the programs finished because of awful lot of bugs within,
but the output clearly shows the facts.
Surely, no problems with networking observed.

What kernel do you use? Also, you may want check your system libraries
(libc, libresolv*).

-alex

Is the linux networking code broken?

[Ed Carp]

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Or have I been smoking too much crack? ;)

I've tried this code on several different linux machines, running 2.0.36 -
2.4.7 kernels, and it always acts the same.  Doing a write() of more than
1024 bytes on a TCP socket always disables all network connectivity on the
sending machine.  (A reboot fixes things, naturally).  I've tried the same
code on FreeBSD 4.5 machines with no problems.  Is this a limitation in
the kernel networking code, in the IP fragmentation layer, or what?  I'm
scratching my head here...thanks in advance for any replies.  Off-list, if
you would be so kind...
- -- 
Ed Carp, N7EKG          http://www.pobox.com/~erc               214/986-5870
Director, Software Development
Escapade Server-Side Scripting Engine Development Team
Pensacola - Dallas - London - Dresden
http://www.squishedmosquito.com


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