commit 84cde06da20a968020de17b90c05bc5299d5ec3f
Author: Fehér Roland Ádám <feherneoh@gmail.com>
Date:   Mon Jun 1 12:17:46 2026 +0200

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b7d3f3e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+arpscan.json
+nmaplog.txt
diff --git a/arpscan.sh b/arpscan.sh
new file mode 100755
index 0000000..d34b265
--- /dev/null
+++ b/arpscan.sh
@@ -0,0 +1,116 @@
+#!/usr/bin/bash
+
+# check for nmap and jq
+# check for root
+
+starttime="$(date '+%Y-%m-%d %H:%M:%S')"
+
+if [ -f arpscan.json ]
+then
+    #tempjson=$(jq '.ips += {} | .ips = ([ .ips | to_entries[] | select(.value.reserved == true) ] | from_entries)' arpscan.json)
+    tempjson=$(jq '.ips += {} | .ips=(.ips|to_entries|map_values(.value.online=false)|from_entries)' arpscan.json)
+    #tempjson="$(cat arpscan.json)"
+    if [ $? -ne 0 ]
+    then
+        echo "Failed to load network JSON" 1>&2
+        exit 1
+    fi
+else
+    exit 1
+fi
+
+jsonescape() {
+    jq -Rs . < <(printf "%s" "${1}")
+}
+
+foundhost() {
+    tempjson=$(jq "$(jsonescape "${1}") as \$ip|.ips[\$ip].mac=$(jsonescape "${2}")|.ips[\$ip].online=true" <<< "${tempjson}")
+}
+
+doscan() {
+    local nmaplog
+    nmaplog=$(sudo nmap -sn -n 192.168.16.0/24)
+    if [ $? -ne 0 ]
+    then
+        echo "nmap failed" 1>&2
+        return 1
+    fi
+    cat <<< "${nmaplog}" > nmaplog.txt
+
+    local parsestep
+    local ipaddr
+    parsestep=waitheader
+    ipaddr=
+
+    while read -r line
+    do
+        case $parsestep in
+            waitheader)
+                if [[ "${line}" != "Starting Nmap "* ]]
+                then
+                    echo "Nmap start header expected, got ${line}" 1>&2
+                    return 1
+                fi
+                parsestep=hostdata
+                ;;
+            hostdata)
+                if [[ "${line}" == "Nmap done: "* ]]
+                then
+                    parsestep=scandone
+                elif [[ "${line}" =~ ^Nmap\ scan\ report\ for\ (.*)$ ]]
+                then
+                    ipaddr="${BASH_REMATCH[1]}"
+                elif [[ "${line}" =~ ^Host\ is\ up(\ \(.*\))?.$ ]]
+                then
+                    continue
+                elif [[ "${line}" =~ ^MAC\ Address:\ ([A-F0-9:]{17}).*$ ]]
+                then
+                    local macaddr
+                    macaddr="${BASH_REMATCH[1]}"
+                    if [[ "${ipaddr}" == "" ]]
+                    then
+                        echo "Found MAC without IP" 1>&2
+                        return 1
+                    fi
+                    foundhost "${ipaddr}" "${macaddr}"
+                    if [ $? -ne 0 ]
+                    then
+                        echo "Registering host failed" 1>&2
+                        return 1
+                    fi
+                    ipaddr=
+                else
+                    echo "Failed to parse: ${line}" 1>&2
+                    return 1
+                fi
+                ;;
+            scandone)
+                echo "Unexpected data after scan: ${line}" 1>&2
+                return 1
+                ;;
+            *)
+                echo "Invalid parse step: ${parsestep}" 1>&2
+                return 1
+                ;;
+        esac
+    done <<< "$nmaplog"
+    #done < nmaplog.txt
+}
+
+doscan
+if [ $? -ne 0 ]
+then
+    echo "Scan failed" 1>&2
+    exit 1
+fi
+
+## make sure the MAC vendor and device/port fields exist
+tempjson="$(jq '.macvendor+={}|.devices+=[]' <<< "${tempjson}")"
+
+tempjson="$(jq '.ips=(.ips|to_entries|sort_by(.key|split(".")|to_entries|map((.value|tonumber)*pow(256;3-.key))|add)|from_entries)' <<< "${tempjson}")"
+
+fancyjson="$(jq '. as $root|$root.macvendor|to_entries|map({key:.value[],value:.key})|from_entries as $vendors|($root.devices|map(.*(.ports[]|with_entries(.key|="port_"+.))))|map_values(del(.ports))|map({key:.port_mac,value:.})|from_entries as $ports|$root.ips|map_values(.port=$ports[.mac]|.vendor=$vendors[.mac[0:8]])' <<< "${tempjson}")"
+
+jq -r '(["[?]","MAC","Vendor","Model","IP","User","Device","Port"],(to_entries|sort_by(.key|split(".")|to_entries|map((.value|tonumber)*pow(256;3-.key))|add)|.[]|[if .value.online then "[#]" else "[ ]" end,.value.mac,.value.vendor,.value.port.model,.key,.value.port.user,.value.port.desc,.value.port.port_name]))|@tsv' <<< "${fancyjson}" | column -ts $'\t'
+
+cat <<< "${tempjson}" > arpscan.json