wifi-scan.zsh

wifi-scan.zsh

wifi-scan() {
  setopt localoptions pipefail errreturn

  local device="$(wifnames | tail -1)"
  local raw

  zparseopts -D -K -E \
    r=raw -raw=raw

  if [[ -z "$device" ]]
  then
    echo_err "Unable to determine wifi device"
    return 1
  fi

  echo_debug "Scanning using $device"
  sudo ip link set dev "$device" up

  local res="$(sudo iw dev "$device" scan)"
  local jres

  local LC_NUMERIC=C

  jres="$(sed -e 's#(on w.*# (on w#g' <<< "$res" | awk '
    BEGIN {
      printf("[\n")
    }
    NF > 0 {
      if ($1 == "BSS") {
        if ($2 ~ /^[a-z0-9:]{17}$/) {
          if (e["MAC"]) {
            printf("{\"mac\":\"%s\",\"ssid\":\"%s\",\"freq\":\"%1.1f\",\"sig\":\"%s\",\"sigpct\":\"%.0d\",\"wpa\":\"%s\",\"wpa2\":\"%s\",\"wep\":\"%s\",\"tkip\":\"%s\",\"ccmp\":\"%s\"},\n",
              e["MAC"], e["SSID"], e["freq"], e["sig"], e["sig%"], e["WPA"], e["WPA2"], e["WEP"], e["TKIP"], e["CCMP"]);
          }
          e["MAC"] = $2;
          e["WPA"] = "n";
          e["WPA2"] = "n";
          e["WEP"] = "n";
          e["TKIP"] = "n";
          e["CCMP"] = "n";
        }
      }
      if ($1 == "SSID:") {
        e["SSID"] = substr($0, index($0,$2));
      }
      if ($1 == "freq:") {
        e["freq"] = $NF / 1000;
      }
      if ($1 == "signal:") {
        e["sig"] = $2 " " $3;
        e["sig%"] = (60 - ((-$2) - 40)) * 100 / 60;
      }
      if ($1 == "WPA:") {
        e["WPA"] = "y";
      }
      if ($1 == "RSN:") {
        e["WPA2"] = "y";
      }
      if ($1 == "WEP:") {
        e["WEP"] = "y";
      }
      if ($4 == "CCMP" || $5 == "CCMP") {
        e["CCMP"] = "y";
      }
      if ($4 == "TKIP" || $5 == "TKIP") {
        e["TKIP"] = "y";
      }
    }
    END {
      printf("{\"mac\":\"%s\",\"ssid\":\"%s\",\"freq\":\"%.1f\",\"sig\":\"%s\",\"sigpct\":\"%.0d\",\"wpa\":\"%s\",\"wpa2\":\"%s\",\"wep\":\"%s\",\"tkip\":\"%s\",\"ccmp\":\"%s\"}\n",
        e["MAC"], e["SSID"], e["freq"], e["sig"], e["sig%"], e["WPA"], e["WPA2"], e["WEP"], e["TKIP"], e["CCMP"]);
      printf("]\n")
    }')"

  # Sanitize JSON
  # FIXME Why do we need to echo here for tr to do its jobs?!
  jres="$(echo "$jres" | tr -d '\000' | tr -d '\t')"

  # Fix frequency display
  jres=$(jq '.[] |=
    if ((.freq | tonumber) < 2.4 or (.freq | tonumber) >=6.0) then (.freq = (.freq | tostring))
    elif ((.freq | tonumber) > 5) then (.freq = "5.0")
    elif ((.freq | tonumber)> 2.0) then (.freq = "2.4")
    else . end' <<< "$jres")

  # Fix signal percentage (it should never exceed 100%)
  jres=$(jq '.[] |=
    if ((.sigpct | tonumber) > 100) then (.sigpct = "100") else . end' \
    <<< "$jres")

  if [[ -n "$raw" ]]
  then
    jq <<< "$jres"
  else
    jq '. |= sort_by(.sigpct | tonumber)' <<< "$jres" | \
    jq -r '
      def colors:
      {
        "black": "\u001b[30m",
        "red": "\u001b[31m",
        "green": "\u001b[32m",
        "yellow": "\u001b[33m",
        "blue": "\u001b[34m",
        "magenta": "\u001b[35m",
        "cyan": "\u001b[36m",
        "white": "\u001b[37m"
      };
      def styles:
      {
        "strikethrough": "\u001b[9m",
        "reset": "\u001b[0m"
      };
    .[] | colors.blue + (if (.ssid == "") then (styles.strikethrough + "[*NONE*] (hidden?)" + styles.reset) else .ssid end) + styles.reset + "\t" + colors.magenta + .mac + "\t" + colors.yellow + .freq + styles.reset + "\t" + colors.green + .sigpct + "%" + styles.reset' | \
    column -t -s '	'
  fi
}

Sample output:

$ wifi-scan
🐛 Scanning using wlan0
UPC956E146          54:67:51:2c:3d:0a  2.4  30%
Vodafone Hotspot    36:2c:94:34:3b:95  2.4  31%
Medusa_13           34:2c:c4:34:3b:95  2.4  33%
Gast_Medusa_13      36:2c:b4:34:3b:95  2.4  35%
UPC562CD8D          54:67:51:08:ce:3b  5.0  35%
Vodafone-3101       d4:3f:cb:89:a0:89  5.0  35%
BeMaFRA             98:9b:cb:71:86:ed  5.0  35%
Vodafone Hotspot    56:67:11:08:ce:63  2.4  40%
BeMaFRA             98:9b:cb:71:86:ee  2.4  41%
Hoeheitsgebiet      ac:22:05:db:4d:22  5.0  43%
o2-WLAN34           a8:d3:f7:96:10:69  2.4  48%
Vodafone Hotspot    92:5c:14:db:21:48  2.4  51%
UPC614F5E5          90:5c:44:db:21:48  2.4  53%
Hoeheitsgebiet      ac:22:05:db:4d:5b  2.4  56%
[*NONE*] (hidden?)  6a:9a:87:e7:90:77  2.4  58%
Vodafone Hotspot    ae:22:15:db:4d:5b  2.4  60%
Vodafone Hotspot    92:5c:14:d1:34:2f  2.4  66%
UPC5144FAF          90:5c:44:d1:34:2f  2.4  68%
UPC5144FAF          90:5c:44:d1:34:20  5.0  71%
Vodafone Hotspot    ae:22:15:e6:ff:41  2.4  83%