ESP32 network discovery through LAN IP scanning and Ethernet ARP monitoring

[Andreas]

@MKO

works sometimes too, but very … verry … slowly.

Sorry to hear that. arpmon.py for Scapy feels reasonably snappy for me, so you might want to try that route. I am looking at this as we can integrate it into our tooling more seamlessly than having to parse output of any other command line tool.

[MKO]

@Andreas

Sorry to hear that. arpmon.py for Scapy feels reasonably snappy for me, so you might want to try that route. I am looking at this as we can integrate it into our tooling more seamlessly than having to parse output of any other command line tool.

sorry for the misunderstanding.
I mean, my ping in a loop on all ip. With this command:
for /l %i in (1,1,255) DO @ping 192.168.178.%i -n 1 | find “Bytes=”

Arp works fast on Windows command
arp -a | find “80-7d-3a”

Arp on Python i have not checked.

[Andreas]

@MKO

sorry for the misunderstanding.

All good, no misunderstanding at all. Following regular ICMP ping requests will always be a magnitude slower, especially when doing that sequentially from userspace.

@MKO

Arp works fast on Windows command

arp -a | find “80-7d-3a”

Right, that’s why I would favor it over actually scanning the network. The Python thing is just that: Watching the network for ARP events. If we could get the basic version work on Windows, I would gain more confidence in going down that route.

I also like this as it will read ARP discovery packages directly from the network probably without touching the operation system’s ARP table at all which sometimes confuses me.

[poesel]

Maybe I’m not understanding the problem but wouldn’t mDNS not solve the issue?

loboris/MicroPython_ESP32_psRAM_LoBo

[Andreas]

@poesel

Wouldn’t mDNS solve the issue?

Sure. We are tracking this over there.

ESP32 network discovery through mDNS with MicroPython

Coming from Investigating ESP32 WiFi connectivity behavior, we are investigating and discussing mDNS support for Pycom MicroPython here.

… just still following both variants to be able to tell them apart.

[poesel]

:) just found the other thread AFTER posting here

[MKO]

i tried in WSL2, looks not so good.

Unfortunately I do not have enough time now, but I’ll see if I can fix it.
Under Windows directly, I seem to have a damaged installation of python. I will try it there again.

[Andreas]

@MKO

I seem to have a damaged installation of python. I will try it there again.

Shit happens. Sorry for that.

@MKO

Unfortunately I do not have enough time now, but I’ll see if I can fix it.

No worries, please take your time and thanks already.

[Andreas]

Some hints for the next iteration.

That probably would happen if you use VM or Windows Subsystem for Linux. Try standard installation, that solved the same problem for me.

Correct: you can’t open a L2-raw socket directly in Python on Windows, therefore Scapy uses [Win]pcap providers to bypass this rule.

SCAPY send packet error OSError: [Errno 97] Address family not supported by protocol

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So yes: Trying to do this on WSL2 will probably not work as the foundation is based on Npcap which will be installed natively on Windows.

– Download and Installation — Scapy 2.5.0 documentation
– Npcap: Windows Packet Capture Library & Driver

[MKO]

I went for Python on Windows with Anaconda. So the easy way, without PATH problems to the libraries.

Michael Yin:
Some articles online trying to teach people to install python, modify PATH env, I must say this method is very complex and it might fail on another windows version, so try to use anaconda, which would save you a lot of time.

It works!

(base) C:\Users\Büro1>python arpmon.py | find "80:7d:3a"
80:7d:3a:c3:39:1c 0.0.0.0
80:7d:3a:c3:39:1c 0.0.0.0
80:7d:3a:c3:39:1c 0.0.0.0
80:7d:3a:c3:39:1c 192.168.178.160
80:7d:3a:c3:39:1c 192.168.178.160
80:7d:3a:c3:39:1c 192.168.178.160
80:7d:3a:c3:39:1c 192.168.178.160
80:7d:3a:c3:39:1c 192.168.178.160

There is still an error message or info in scapy:

[Andreas]

@MKO

Python on Windows with Anaconda. The easy way.

@MKO

It works!

Excellent, thanks. Don’t worry about the info output of the scapy program, we will just use it as a library.

---

So, essentially you have to install Anaconda, Npcap and Scapy ^[1] natively on Windows to get things going – right?

---

1. by invoking like conda install scapy? ↩︎

[MKO]

@Andreas

So, essentially you have to install Anaconda, Npcap and Scapy [1] natively on Windows to get things going – right?

1. by invoking like conda install scapy ? ︎

yes, just install anaconda and then scapy with :

conda install -c conda-forge scapy

I did not need to install Npcap additionally.

But i will test, on an another computer again, from the beginning, at first without Anaconda.
My windows and not phyton are on this System damage, I don´t come to the path settings. Probably it was damaged during the update to win 10.

[Andreas]

Outcome

We have been able to make some way into an implementation and described the outcome within
Terkin Agent and Wartungsmodus für den Terkin-Datenlogger.

Synopsis

Displays successful device discovery and maintenance mode enablement.

$ sudo python3 -m tools.terkin maintain

2019-07-10 19:49:21,698 [tools/terkin.py] INFO   : IP networks found: ['192.168.178.0/24']
2019-07-10 19:49:21,698 [tools/terkin.py] INFO   : Sending an ARP ping to discover already connected devices on network 192.168.178.0/24
2019-07-10 19:49:21,698 [tools/terkin.py] INFO   : Waiting for any devices having MAC address prefixes of ['30:ae:a4', '80:7d:3a'] to appear on your local network
2019-07-10 19:49:25,172 [tools/terkin.py] INFO   : Found device at {'mac': '80:7d:3a:c2:de:44', 'ip': '192.168.178.166'}
2019-07-10 19:49:25,172 [tools/terkin.py] INFO   : Connecting to device mode server at 192.168.178.166:666
2019-07-10 19:49:25,172 [tools/terkin.py] INFO   : Pulling 192.168.178.166 into maintenance mode