Real-Time Updating Dumb AP Associated Stations!

[woodhead]

Were you aware that WDS clients (wifi extender) get the hostnames (and ip-addresses) with no extra configuration?

[Trigger31337]

@fow0ryl

All dhcp leases are displayed on the Dumb AP in the overview, including those that actually have nothing to do with the Dumb AP.

Weird.
As of 23.05, I'm seeing all and only the clients associated with the WAP... not "all DHCP leases" as you describe.
I also see non-static leases appear with only their IP address (no hostname)

FWIW, I was running it with synched /etc/ethers across all APs and main router, but have since emptied out all the ethers files in the APs and it still works fine.

[fow0ryl]

Maybe something has changed in 23.nn
Until now only 22.nn firmware here ...

[_FailSafe]

FWIW, I’ve gone with the DHCP hotplug based approach as well, but it can be very “chatty” at times. So in order to not re-send duplicate data for every DHCP hotplug event, I accounted for it with a script I posted here:

Associated stations - making hostnames visible across multiple APs

FWIW, here's the approach I have taken. Feel free to ignore it or take bits from it that you like. Some background... In order to reduce writes to /etc/ethers on each AP, I symlink /etc/ethers (on each AP) to a location, /tmp/etc/ethers: root@AP-Office:~# ls -la /etc/ethers lrwxrwxrwx 1 root root 15 Apr 22 15:40 /etc/ethers -> /tmp/etc/ethers I add the following to my /etc/rc.local file on each AP: if [ ! -f /tmp/etc/ethers ]; then touch /tmp/etc/ethers; fi ln -sf /tmp/etc…

@eR2022

chmod +x /etc/hotplug.d/dhcp/<scriptfilename>

To make the script file executable.

Hotplug scripts are sourced and therefore do not need to be executable. This step is not needed, nor recommended.

[mans]

@eR2022

Create script in /etc/hotplug.d/dhcp and chmod +x the file

Should I do this in the main router or dumbAP?

Additionally will this method show Active DHCP Leases which is present in the main router, in the dumbAP?

I just tried everything in the main router and it doesn't work with the latest OpenWrt. Still a "?" shown on the dumbAP.

[_FailSafe]

@eR2022

Create script in /etc/hotplug.d/dhcp and chmod +x the file

@_FailSafe

Hotplug scripts are sourced and therefore do not need to be executable. This step is not needed, nor recommended.

The hotplug.d script goes in your main router. But note the point about hotplug.d scripts should not be executable, as I mentioned previously.

@mans

Additionally will this method show Active DHCP Leases which is present in the main router, in the dumbAP?

No, not in the sense that I believe you're asking. When you view the Network-->Wireless section, Associated Stations will show hostnames for the associated clients. That is the intent of this script.

[Cthulhu88]

This seems like an often sought feature, but all these high-level scripting approaches leave much to be desired (hacky, high overhead, not atomic, etc).

Associated stations - making hostnames visible across multiple APs

To be honest, I don't like any of the solutions for this problem. I was thinking, maybe a simple server/client pair written in C. Main router monitors new clients entering and leaving the network (server mode). Dumb AP establishes an unicast (avoid generating extra multicast noise) connection with the main router server (client mode). Main router sends all current info to dumb AP. Main router keeps updating the dumb AP with new info until the connection is closed.

Just an idea. You can create a socket through socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL)) and capture ethernet frames, which you can then map MAC addresses to IP addresses and relay pairs to connected dumb APs.

Server: server -i interface -a address -p port
Client: client -a address -p port -s script.sh

Is this something people would be willing to compile for them their own devices?

[Cthulhu88]

As suspected, I can catch those ARP frames in the dumb AP directly.

root@router2:/mnt/root# gcc -std=c89 -O2 -Wall -Wextra -Wpedantic -idirafter /mnt/usr/include -o warpmon warpmon.c
root@router2:/mnt/root# ./warpmon
[ARP] MAC: XX:XX:XX:XX:XX:XX, IP: 192.168.0.168
[ARP] MAC: XX:XX:XX:XX:XX:XX, IP: 192.168.0.1
[ARP] MAC: XX:XX:XX:XX:XX:XX, IP: 192.168.0.118
[ARP] MAC: XX:XX:XX:XX:XX:XX, IP: 192.168.0.1
[ARP] MAC: XX:XX:XX:XX:XX:XX, IP: 192.168.0.226
[ARP] MAC: XX:XX:XX:XX:XX:XX, IP: 192.168.0.143

In this example, it's only catching ether frames in the phy0-ap0 interface. Currently, I've only implemented the capture (single interface), still need to implement CLI options and implement adding those entries to the local ARP table.