OpenWrt-list-client-devices

Lightweight OpenWrt script to show all client devices no matter the connection type (Wired, Wireless, DHCP or Static).

This can be considered a programmatic and better way to LuCi's Status > Routing - IP Neighbors

Example output

IP Address                MAC Address       Vendor (MAC)              Hostname                 Iface          Method     State
-----------------------------------------------------------------------------------------------------------------------------
10.10.123.1               e8:39:35:ed:d6:30 Hewlett Packard           Hp                       Pi (eth4)      DHCP       STALE
10.10.123.4               28:70:4e:32:36:5e Ubiquiti Inc              USW-Flex-Mini            Pi (eth4)      DHCP       DELAY
10.10.2.100               00:13:1c:21:ca:84 LiteTouch, Inc.           *                        Pa (eth1)      DHCP       STALE
10.10.2.4                 b0:6e:bf:bb:5c:61 ASUSTek COMPUTER INC.     PC                       Pa (eth1)      DHCP       REACHABLE
169.254.216.15            b0:6e:bf:bb:5c:61 ASUSTek COMPUTER INC.     PC                       Pa (eth1)      DHCP       STALE
10.10.5.123               a6:0d:e5:cc:21:aa -                         iPad                     - (wlan2)      DHCP       STALE
192.168.0.1               9c:53:22:de:10:43 TP-Link Systems Inc       -                        wan (eth0)     Static/?   REACHABLE
192.168.0.10              00:13:1b:4a:a0:a9 -                         -                        wan (eth0)     Static/?   STALE
192.168.0.238             -                 -                         -                        wan (eth0)     Static/?   FAILED

Note that Vendor might not be displayed properly due the the request limits on https://api.macvendors.com when run for first couple of times...

Install

You need to have basic commands (ip, grep, awk, sed etc...) available. Also bash (if you do not have it already):

opkg update
opkg install bash

Switch to bash

cat << 'THE_END' > /bin/list-clients && chmod +x /bin/list-clients && sed -i -e 's/\t//g' -e '/^[[:space:]]*$/d' -e '/^# /d' /bin/list-clients && grep -qxF '/bin/list-clients' /etc/sysupgrade.conf || echo '/bin/list-clients' >> /etc/sysupgrade.conf
#!/bin/sh

LEASES="/tmp/dhcp.leases"
ETHS="/etc/ethers"
MAC_VENDORS="/etc/mac-vendors.db"

# Mac vendor cahce
MAC_CACHE=$(cat "$MAC_VENDORS" 2>/dev/null)

# Print header
printf "%-28s %-17s %-34s %-25s %-22s %-10s %-10s\n" "IP Addr" "MAC Addr" "Vendor (MAC)" "Hostname" "Iface / SSID (dev)" "Method" "State"
printf %155s | tr \  -
echo

elap=0

ip neigh | sort | while read -r l; do
	ip=$(echo "$l" | awk '{print $1}')
	ifc=$(echo "$l" | sed -n 's/.* dev \([^ ]*\).*/\1/p')
	mac=$(echo "$l" | sed -n 's/.* lladdr \([^ ]*\).*/\1/p')
	state=$(echo "$l" | awk '{print $NF}')

	[ -z "$ip" ] && ip="-"
	[ -z "$ifc" ] && ifc="-"
	[ -z "$state" ] && state="-"

	# Hostname & Method detection
	host=$(awk -v mac="$mac" '$2 == mac {print $4}' "$LEASES" 2>/dev/null)
	meth="Static/?"
	if [ -n "$host" ]; then
		meth="DHCP"
	elif grep -qi "^[[:space:]]*$mac[[:space:]]" "$ETHS" 2>/dev/null; then
		meth="Static"
		[ -z "$host" ] && host=$(awk -v mac="$mac" 'BEGIN{IGNORECASE=1} $1==mac {print $2}' "$ETHS" 2>/dev/null)
	fi
	[ -z "$host" ] && host="-"

	# Mac vend lookup with local cache
	vend="-"
	pref=$(echo "$mac" | tr '[:lower:]' '[:upper:]' | cut -d: -f1-3)

	[ -n "$pref" ] && vend=$(echo "$MAC_CACHE" | grep -i "^$pref=" | head -n1 | cut -d= -f2-)

	if [ -z "$vend" ] && [ "$pref" != "---" ] && [ "$elap" -lt 4 ]; then
		t0=$(date +%s)
		jsn=$(wget -qO- "https://api.maclookup.app/v2/macs/$mac" 2>/dev/null)
		elap=$(($(date +%s) - t0))

		resp=$(printf "%s" "$jsn" | sed -E 's/.*"company": *"([^"]*)".*/\1/')
		[ -z "$resp" ] && [ "$(printf "%s" "$jsn" | sed -E 's/.*"isRand": *([^,}]*).*/\1/')" = "true" ] && resp="*RAND*"

		if [ -n "$resp" ]; then
			vend="$resp"
			echo "$pref=$vend" >> "$MAC_VENDORS"
			MAC_CACHE="${MAC_CACHE}${MAC_CACHE:+
}$pref=$vend"
		fi
	fi
	[ -z "$mac" ] && mac="-"
	[ -z "$vend" ] && vend="-"

	owrtIfc=$(uci show network 2>/dev/null | grep "$ifc" | cut -d. -f2 | cut -d= -f1 | head -n1)
	[ -z "$owrtIfc" ] && owrtIfc=$(iwinfo "$ifc" i 2>/dev/null | sed -n 's/.*ESS..: "\(.*\)".*/\1/p')
	[ -z "$owrtIfc" ] && owrtIfc=$(iw dev "$ifc" info 2>/dev/null | awk -F 'ssid ' '/ssid/ {print $2}')
	[ -z "$owrtIfc" ] && owrtIfc="-"

	printf "%-28s %-17s %-34.34s %-25.25s %-22.22s %-10s %-10s\n" "$ip" "$mac" "$vend" "$host" "$owrtIfc ($ifc)" "$meth" "$state"
done

THE_END

Now you can simply run it as list-clients and add it as a Custom command (System > Custom commands) to LuCi!
Optionally you can add iw or iwinfo to if you want your wireless SSID to be resolved as fallback for Iface.

Note that command might not work properly if not run with root privileges. Also, the list-clients itself does not require bash to run so after you are done with the install script, you can uninstall bash if you want...