[Networktest-sctp] SCTP test suite setup: connecting 2 ttyS0's over TCP/IP

[Daniel B. <bor...@io...>]

Hi together,

I'm trying to setup two remotely connected machines (different places
on the Internet) with the description mentioned in [1]. The
installation of the software described there is no problem, since
everything seems to work *so far*, but I cannot get the two ttyS0's
connected together.

Since the two machines do obviously not have a direct serial link, I
need to get them connected over TCP/IP, also in order to test
different Linux kernels easily/quickly.

I tried to get this link set up via socat [2], but didn't succeed.
After following [1], I did

NUT machine:

  socat tcp-l:54321,reuseaddr,fork
file:/dev/ttyS0,nonblock,raw,echo=0,waitlock=/var/run/tty

TN machine:

  while true; do socat pty,link=/tmp/vmodem0,raw,echo=0,waitslave
tcp:<NUT-host>:54321; done

And then on TN: cu -l /tmp/vmodem0 resp. I also tried opening it with
minicom - no success. I also removed 'waitslave', because I saw via
strace that with active 'waitslave', the client doesn't even try to
connect to the remote server. I also tried replacing ttyS0 with tty0,
removing ',raw,echo=0', etc, nothing helped.

Did you have similar experiences and could you solve this via socat?
Or, did you do this conformance test locally on your laptop via VMs?

Locally, I gave it a try with Qemu/KVM, but couldn't solve it there either:

  mkfifo /tmp/serialbridge

NUT guest:

  qemu-system-x86_64 -hda debian_squeeze_amd64_standard-NUT.qcow2 -net
nic -net user -m 2048 -enable-kvm -cpu host -machine type=pc,accel=kvm
-serial pipe:/tmp/serialbridge

TN guest:

  qemu-system-x86_64 -hda debian_squeeze_amd64_standard-TN.qcow2 -net
nic -net user -m 2048 -enable-kvm -cpu host -machine type=pc,accel=kvm
-serial pipe:/tmp/serialbridge

... where I am not sure if the 'serial' configuration is the right one
(probably not). When I try to connect them, one machine does a CPU
soft-lockup in the kernel within the serial device's IRQ handler, and
thus becomes unusable. (My host machine is a Fedora 17, with i) Qemu
tried from the Fedora repository, and ii) build from scratch from the
Qemu Git repository.)

On all machines I also tried with console=ttyS0 on the kernel command
line, no success either.

If you have some pointers, I'd be very glad.

Daniel

[1] http://networktest.sourceforge.net/usage.html
[2] http://www.dest-unreach.org/socat/doc/socat-ttyovertcp.txt