Find a way to determine if kotnetcli is connected to the KotNet network. If this is True, login. It this is False: exit gracefully

[jovanbulck]

When netlogin.kuleuven.be server is not responding, it means the user is not on a KotNet network and therefore kotnetcli should exit gracefully with an exit code and information message (if not --quiet) to inform the user

[GijsTimmers]

Done. https://github.com/GijsTimmers/kotnetcli/commit/1b92df571e4b36dc1b47b09af8fc353077c310d2

[GijsTimmers]

Although netlogin.kuleuven.be can't be reached from home via a web browser, it does respond to ping requests. So we need another technique to figure out if the user is on KotNet or not. This may also explain the problems you were having running kotnetcli on-campus.

Some alternatives:

• Check whether the IP is in the KotNet range (10.x.x.x), so definitely not the best solution
• Check whether mechanize is able to load a valid HTML file from netlogin.kuleuven.be
• Check whether we can ping netlogin.kuleuven.be.
  • If we cannot, that means that there's a network problem. Exit.
  • If we can, that means that we are connected to a network. Check if we can ping a conventional website (I suggest toledo.kuleuven.be).
  • If we can, that means that we are already online. We don't know whether we are online on the KotNet network or a home network, so just exit. (this would remove the option to log in anyway)
  • If we cannot, that means that we are on the KotNet network, but we are not yet logged in. Proceed normally.

[jovanbulck]

I found something interesting you should test: https://admin.kuleuven.be/icts/english/kotnet/diagnosis

Note the bold note at the bottom ;-)

[GijsTimmers]

Very interesting, we should check if this works both at home and at kot.

At home:

The server does respond to ping -s 1472 -c 100 134.58.126.3

[GijsTimmers]

KotNet's broadcast addres is 10.92.39.255. Maybe we can use that to determine if we're on the KU Leuven network.

[GijsTimmers]

https://github.com/GijsTimmers/kotnetcli/commit/d3759145e09e272b0da83f10d5c168bad8223564

[jovanbulck]

I can't test now in dev branch since dev still crashes on communicator factory pattern:

Traceback (most recent call last): File "./kotnetcli.py", line 317, in aanstuurderObvArgumenten(argumentenParser()) File "./kotnetcli.py", line 247, in aanstuurderObvArgumenten fab = LoginCommunicatorFabriek() NameError: global name 'LoginCommunicatorFabriek' is not defined

I could create a patch from your commit and apply it to master locally to see if it works, but looking at the code I wonder whether it will because gateway is defined as xx.xx.xx.xx

Then again, ideally we would find a better way as the standard gatway address is that of the NAT router inside kot I think. So it wont be the same on all kots and may clash likely with another home default gateway...

[GijsTimmers]

Hi, could you run this code snippet? (First install netifaces using pip)

import netifaces
print netifaces.gateways()["default"][netifaces.AF_INET][0]

What IP does it return? We need to check this on different kots.

[GijsTimmers]

@Wouter92 could you do the same?

[jovanbulck]

I'm pretty sure it's a bad strategy since one has control over once own default gateway on network setup (so even if most of kotnets setups have the same default gateway its still ugly.) I'll think about something better...

I'll try this evening on kot. If helpful, this is the default gateway in the library (non-kotnet):

10.43.127.254

[jovanbulck]

It's probably easy: instead of pinging netlogin.kuleuven.be we should see if we can open a https connection

nmap -p 443 netlogin.kuleuven.be or so will probably do the job...

[GijsTimmers]

I'm pretty sure it's a bad strategy since one has control over once own default gateway on network setup

I'm not so sure about that, actually. IIRC, KotNet manages the DHCP and thus hands out the IP's . The routers on-kot merely act as a switch.

It's probably easy: instead of pinging netlogin.kuleuven.be we should see if we can open a https connection

Good idea.

[jovanbulck]

I'm not so sure about that, actually. IIRC, KotNet manages the DHCP and thus hands out the IP's . The routers on-kot merely act as a switch.

Yep indeed, I'm not sure neither. I think however the default gateway is the first router in line to send requests to; it can subsequently forward if needed. I"m back in doubt however. You could very well be right...

Anyway: here's the result

10.92.32.1

and the nmap trick above seems to work on kot and not in library :-) So maybe this is the way to go (there will surely be some python support to try set up a TCP connection on port 433 which is https)

[Wanimatrix]

This is my result:

10.92.80.1

[GijsTimmers]

Thank you both for testing this. It seems like Kotnet hands out 10.92.xx.x IP's. Regardless, I think that Jo's solution is better.

From my home:

[gijs@xiphos ~]$ nmap -p 443 netlogin.kuleuven.be

Starting Nmap 6.46 ( http://nmap.org ) at 2015-01-24 13:45 CET
Note: Host seems down. If it is really up, but blocking our ping probes, try -Pn
Nmap done: 1 IP address (0 hosts up) scanned in 3.09 seconds

So, we'll execute a HTTPS request to ensure that we're on the kotnet network.

[jovanbulck]

Try the following code in a python interpreter. It works fine here :-)

import socket

def test():
    print "================ KOTNET CONNECTION TEST ================"
    ## try to open a TCP connection on port 443 with a timeout of 1.5 second
    try:
        sock = socket.create_connection(("netlogin.kuleuven.be", 443), 1.5)
        sock.close()
        print "I could successfully connect to netlogin.kuleuven.be"
    except:
        print "Connection attempt to netlogin.kuleuven.be timed out. Are you on the kotnet network?"

test()

[GijsTimmers]

In [1]: import socket

In [2]: def test():
    print "================ KOTNET CONNECTION TEST ================"
    try:
        sock = socket.create_connection(("netlogin.kuleuven.be", 443), 1.5)
        sock.close()
        print "I could successfully connect to netlogin.kuleuven.be"
    except:
        print "Connection attempt to netlogin.kuleuven.be timed out. Are you on the kotnet network?"

In [3]: test()
================ KOTNET CONNECTION TEST ================
Connection attempt to netlogin.kuleuven.be timed out. Are you on the kotnet network?

Nice code, I really like the lightweight socket import.

[jovanbulck]

ok,

I implemented this in the dev branch, as linked above. I moved the functionality from tools/pinger to browser as it fits more cohesively I think. Moreover this allows us to override the behavior in the DummyBrowser :-)

Should work nicely. If not we reopen this issue