kaa rpc and IPV6

dear all,

I have been trying to get freevo 1.9.2b2 up and running for some
days ; I uploaded a version in Debian that is reasonably fine
(though there are some bugs... I'll post them later on); but I had
one major showstopper that I wanted to share.

The showstopper was this: when I tried to install freevo 1.9.2b2
(and newer kaa from SVN) in my usual freevo-PC , freevo could not
talk to its recordserver. This was quite weird, since it all worked
fine in my notebook (!!)

After many (many!) hours of trial-and-error, I wrote the two scripts
in attachment. The scripts expose a problem , that AFAICT may be
(according to tracebacks) in _resolve_hostname_with_action
in "kaa/base/sockets.py"

Problem: it seems that SVN kaa rpc , binds to IPV6 but ignores IPV4

Note that it makes a difference if in your /etc/hosts.file you have

::1 ip6-localhost ip6-loopback

or

::1 localhost ip6-localhost ip6-loopback

I will call the first situation [L4] and the second [L6]

FYI [L6] is the situation in the notebook ; [L4] in the freevo-PC

-----------------------------------

In [L4], when you start the server without hostname

# python kaa_rpc_server_test.py &

then this server cannot be reached using default argument,

# python kaa_rpc_client_test.py

Contacting the server on localhost

CONNECTING

Traceback (most recent call last):

File "kaa_rpc_client_test.py", line 12, in <module>

kaa.inprogress(channel).wait()

File "/usr/lib/pymodules/python2.6/kaa/base/async.py", line
720, in wait

return self.result

File "/usr/lib/pymodules/python2.6/kaa/base/async.py", line
353, in result

raise self._exception[1]

kaa.base.async.AsyncException: Exception raised asynchronously;
traceback follows:

File "/usr/lib/pymodules/python2.6/kaa/base/thread.py", line
181, in __call__

result = self._callable()

File "/usr/lib/pymodules/python2.6/kaa/base/callable.py", line
226, in __call__

return cb(*cb_args, **cb_kwargs)

File "/usr/lib/pymodules/python2.6/kaa/base/sockets.py", line
527, in _connect

self._resolve_hostname_with_action(addr, sock.connect, ipv6)

File "/usr/lib/pymodules/python2.6/kaa/base/sockets.py", line
436, in _resolve_hostname_with_action

func(addrinfo)

File "<string>", line 1, in connect

error: [Errno 101] Network is unreachable

but it can be reached using

python kaa_rpc_client_test.py ip6-localhost

-------------------------------------------------------

In [L6], when you start the server without hostname

# python kaa_rpc_server_test.py &

then this server can be reached,

# python kaa_r$ python2.6 kaa_rpc_client_test.py

Contacting the server on localhost

CONNECTING

CONNECTED

ciao

-----------

both in [L4] and [L6], moreover, netstat does not find the server
as a IPV4 , only as IPV6

$ netstat --inet6 -a | grep 19999

tcp6 0 0 [::]:19999
[::]:* LISTEN

$ netstat --inet -a | grep 19999

[NO OUTPUT]

---------

in [L4], trying to force the hostname to be '127.0.0.1' has this
effect

# python kaa_rpc_server_test.py 127.0.0.1 &

Starting a server that listens on 127.0.0.1

Traceback (most recent call last):

File "kaa_rpc_server_test.py", line 15, in <module>

rpc = kaa.rpc.Server((host,19999),'secret')

File "/usr/lib/pymodules/python2.6/kaa/base/rpc.py", line 169,
in __init__

self._socket.listen(address)

File "/usr/lib/pymodules/python2.6/kaa/base/sockets.py", line
511, in listen

self._resolve_hostname_with_action(addr, sock.bind, ipv6)

File "/usr/lib/pymodules/python2.6/kaa/base/sockets.py", line
436, in _resolve_hostname_with_action

func(addrinfo)

File "<string>", line 1, in bind

socket.error: [Errno 22] Invalid argument

---------------------

in [L6] it works but AFAICT the netstat is weird

$ netstat --inet -an | grep 19999

$ netstat --inet6 -an | grep 19999

tcp6 0 0 127.0.0.1:19999
:::* LISTEN

-----------------

also since my local network is IPV4 only, I cannot contact the
rpc_kaa_server on one machine using another machine

a.

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import sys
import kaa
import kaa.rpc

host='localhost'
if len(sys.argv)>1:
	host=sys.argv[1]
print 'Contacting the server on ', host

channel = kaa.rpc.connect((host,19999),'secret', retry=1)
print channel.status
kaa.inprogress(channel).wait()
print channel.status
if channel.status != kaa.rpc.CONNECTED:
	print 'ARGH'
else:
	inprogress = channel.rpc('ping')
	inprogress.wait()
	print inprogress.result

import sys
import kaa
import kaa.rpc

host=''
if len(sys.argv)>1:
	host=sys.argv[1]
print 'Starting a server that listens on ', (host or 'every inbound call')

class R:
	@kaa.rpc.expose('ping')
	def ping(self):
		return 'ciao'

rpc = kaa.rpc.Server((host,19999),'secret')
r=R()
rpc.register(r)
print('kaa.main starting')
kaa.main.run()
print('kaa.main finished')

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