aredn/files/www/cgi-bin/scan

#!/usr/bin/lua
--[[

	Part of AREDN -- Used for creating Amateur Radio Emergency Data Networks
	Copyright (C) 2021 Tim Wilkinson
	Original Perl Copyright (C) 2015 Conrad Lara
	See Contributors file for additional contributors

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation version 3 of the License.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.

	Additional Terms:

	Additional use restrictions exist on the AREDN(TM) trademark and logo.
		See AREDNLicense.txt for more info.

	Attributions to the AREDN Project must be retained in the source code.
	If importing this code into a new or existing project attribution
	to the AREDN project must be added to the source code.

	You must not misrepresent the origin of the material contained within.

	Modified versions must be modified to attribute to the original source
	and be marked in reasonable ways as differentiate it from the original
	version

--]]

require("aredn.http")
require("aredn.hardware")
local html = require("aredn.html")
local aredn_info = require("aredn.info")

local node = aredn_info.get_nvram("node")
if not node then
    node = "NOCALL"
end
local wifiiface = aredn.hardware.get_iface_name("wifi")
local phy = iwinfo.nl80211.phyname(wifiiface)
local rfband = aredn.hardware.get_rfband()
local nf = iwinfo.nl80211.noise(wifiiface) or -95

if not nixio.fs.stat("/tmp/web") then
    nixio.fs.mkdir("/tmp/web")
end

-- scan start

local scanned = {}
os.execute("echo 'chanscan' > /sys/kernel/debug/ieee80211/" .. phy .. "/ath9k/spectral_scan_ctl")
local f = io.popen("iw dev " .. wifiiface .. " scan passive")
if f then
    local scan
    for line in f:lines()
    do
        local m = line:match("^BSS ([%da-fA-F:]+)")
        if m then
            scan = {
                mac = m,
                mode = "AP",
                ssid = "",
                signal = 0,
                freq = 0,
                key = ""
            }
            scanned[#scanned + 1] = scan
            if line:match("joined") then
                scan.mode = "My Ad-Hoc Network"
            end
        end
        m = line:match("freq: (%d+)")
        if m then
            scan.freq = tonumber(m)
        end
        m = line:match("SSID: (.+)")
        if m then
            scan.ssid = m
        end
        m = line:match("signal: ([%d-]+)")
        if m then
            scan.signal = tonumber(m)
        end
        m = line:match("Group cipher: (.+)")
        if m then
            scan.key = m
        end
        if line:match("capability: IBSS") and scan.mode == "AP" then
            scan.mode = "Foreign Ad-Hoc Network"
        end
    end
    f:close()
end

local samples = io.open("/sys/kernel/debug/ieee80211/" .. phy .. "/ath9k/spectral_scan0", "rb"):read("*a")
os.execute("echo 'disable' > /sys/kernel/debug/ieee80211/" .. phy .. "/ath9k/spectral_scan_ctl")

local f = io.popen("iw dev " .. wifiiface .. " station dump")
if f then
    local scan
    local myssid = aredn_info.getSSID()
    local myfreq = tonumber(aredn_info.getFreq())
    for line in f:lines()
    do
        local m = line:match("^Station ([%da-fA-F:]+) %(on " .. wifiiface .. "%)")
        if m then
            scan = {
                mac = m,
                mode = "Connected Ad-Hoc Station",
                ssid = myssid,
                signal = 0,
                freq = myfreq,
                key = ""
            }
            scanned[#scanned + 1] = scan
        end
        m = line:match("signal avg:%s+([%d-]+)")
        if m then
            scan.signal = tonumber(m)
        end
    end
    f:close()
end

-- scan end

if os.getenv("REQUEST_METHOD") == "POST" then
    require('luci.http')
    require('luci.sys')
    local request = luci.http.Request(luci.sys.getenv(),
      function()
        local v = io.read(1024)
        if not v then
            io.close()
        end
        return v
      end
    )
    if request:formvalue("auto") then
        io.open("/tmp/web/autoscan", "w"):close()
    end
    if request:formvalue("stop") then
        os.remove("/tmp/web/autoscan")
    end
end

-- generate page
http_header()
html.header(node .. " WiFi scan", false)
local autoscan = nixio.fs.stat("/tmp/web/autoscan");
if autoscan then
    html.print("<meta http-equiv='refresh' content='5;url=/cgi-bin/scan'>")
end
html.print([[
    <script src="/js/sorttable-min.js"></script>
    <style>
    table.sortable thead {                                          
        background-color:#eee;                                     
        color:#666666;                            
        font-weight: bold;
        cursor: default;                                               
    }                                                                      
    </style>
    </head>
    <body><form method=post action=/cgi-bin/scan enctype='multipart/form-data'>
    <center>
]])

html.alert_banner()
html.print("<h1>" .. node .. " WiFi scan</h1><hr>")

if autoscan then
    html.print("<input type=submit name=stop value=Stop title='Abort continuous scan'>")
else
    html.print("<input type=submit name=refresh value=Refresh title='Refresh this page'>")
    html.print("&nbsp;&nbsp;&nbsp;")
    html.print("<input type=submit name=auto value=Auto title='Begin continuous scan'>")
end

html.print("&nbsp;&nbsp;&nbsp;")
html.print("<button type=button onClick='window.location=\"status\"' title='Return to status page'>Quit</button><br><br>")

-- display scan
html.print("<table class=sortable border=1 cellpadding=5>")
html.print("<tr><th>SNR</th><th>Signal</th><th>Chan</th><th>Enc</th><th>SSID</th><th>Hostname</th><th>MAC/BSSID</th><th>802.11 Mode</th></tr>")

-- load arp cache
local arpcache = {}
arptable(function(a)
    arpcache[a["HW address"]] = a["IP address"]
end)

local scanlist = {}
for _, v in ipairs(scanned)
do
    if v.signal ~= 0 then
        scanlist[#scanlist + 1] = v
    end
end
table.sort(scanlist, function(a, b) return a.signal > b.signal end)
for _, scan in ipairs(scanlist)
do
    -- freq to chan
    local chan = scan.freq
    if chan < 256 then
    elseif chan == 2484 then
        chan = 14
    elseif chan == 2407 then
        chan = 0
    elseif chan < 2484 then
        chan = (chan - 2407) / 5
    elseif chan < 5000 then
    elseif chan < 5380 then
        chan = (chan - 5000) / 5
    elseif chan < 5500 then
        chan = chan - 2000
    elseif chan < 6000 then
        chan = (chan - 5000) / 5
    end
    -- ip lookup then host lookup
    local ip = arpcache[scan.mac]
    if ip then
        hostname = ip
        local f = io.popen("nslookup " .. ip)
        if f then
            for line in f:lines()
            do
                local m = line:match("name = (.*)%.local%.mesh")
                if m then
                    hostname = m
                    break
                end
            end
            f:close()
        end
    else
        hostname = "N/A"
    end
    if scan.ssid:match("^AREDN-") then
        html.print("<tr class=\"wscan-row-node\">")
    else
        html.print("<tr>")
    end
    html.print("<td>" .. (scan.signal - nf) .. "</td><td>" .. scan.signal .. "</td><td>" .. chan .. "</td><td>" .. scan.key .. "</td><td>" .. scan.ssid .. "</td><td align=center>" .. hostname .. "</td><td>" .. scan.mac:upper() .. "</td><td>" .. scan.mode .. "</td>")
    html.print("</tr>")
end

html.print("</table><br></center>")

-- Spectral information
local cwidth = 800;
local cheight = 400;
html.print([[
    <center style="font-family: Arial">
    <div style="padding:8px">Spectral View</div>
    <div style="position:relative;display:inline-block">
      <div style="position:absolute;top:200px;left:-35px;transform:rotate(-90deg)">SNR</div>
      <canvas id="spectral" width="]] .. cwidth .. [[" height="]] .. cheight .. [[" style="border:1px solid grey;background-color:white"></canvas>
      <div style="position:absolute;display:inline-block;vertical-align:top;text-align:left;top:6px;left:35px;background-color:white;border:solid 1px grey;padding:10px;font-size:12px;line-height:16px">
        <div><span style="background-color:mediumpurple">&nbsp;&nbsp;&nbsp;</span> 5% of traffic</div>
        <div><span style="background-color:yellow">&nbsp;&nbsp;&nbsp;</span> 95% of traffic</div>
        <div><span style="background-color:red">&nbsp;&nbsp;&nbsp;</span> Ambient noise</div>
      </div>
    </div>
    <div style="padding:4px">Channel</div>
    </center>
    <script>
        const canvas = document.getElementById("spectral");
        const ctx = canvas.getContext("2d");
]]);

function u8tos8(b)
    return b >= 128 and b - 256 or b
end

local cnf = nf - 17.5 -- sub-carrier noise floor
if bw == 10 then
    cnf = cnf - 3
elseif bw == 5 then
    cnf = cnf - 6
end
local start_freq
local end_freq
if rfband == "900" then
    start_freq = 902
    end_freq = 925
    html.print("const freq2chan = (f) => (f - 887) / 5;");
elseif rfband == "2400" then
    start_freq = 2377
    end_freq = 2477
    html.print("const freq2chan = (f) => (f - 2407) / 5;");
elseif rfband == "3400" then
    -- transverted
    start_freq = 5370
    end_freq = 5505
    html.print("const freq2chan = (f) => (f - 5000) / 5;");
else
    start_freq = 5650
    end_freq = 5920
    html.print("const freq2chan = (f) => (f - 5000) / 5;");
end
local bw = 10

local fbuckets = {}
for freq = 1, (end_freq - start_freq + bw) * 56 / bw
do
    fbuckets[math.floor(freq)] = {}
end

local xscale = cwidth / (end_freq - start_freq)
local min_sig = -125
local max_sig = -60
local i = 1
while i < #samples
do
    local t = samples:byte(i)
    local l = samples:byte(i + 1) * 256 + samples:byte(i + 2)
    if t == 1 then
        local max_exp = samples:byte(i + 3)
        local freq = samples:byte(i + 4) * 256 + samples:byte(i + 5)
        if freq >= start_freq and freq <= end_freq then
            local rssi = u8tos8(samples:byte(i + 6))
            local noise = u8tos8(samples:byte(i + 7))
            local datasqsum = 0
            local v = {}
            for dptr = 1,56
            do
                local data = nixio.bit.lshift(samples:byte(dptr + i + 19), max_exp)
                data = data * data
                datasqsum = datasqsum + data
                v[dptr] = data
            end
            for dptr = 1,56
            do
                local datasq = v[dptr]
                if datasq ~= 0 then
                    local sig = noise + rssi + 10 * math.log10(datasq / datasqsum)
                    if sig >= min_sig then
                        if sig > max_sig then
                            max_sig = sig
                        end
                        local bidx = math.floor((freq - start_freq) / bw * 56 + dptr - 28)
                        local bucket = fbuckets[bidx]
                        if bucket then
                            bucket[#bucket + 1] = math.floor((sig - min_sig) * 4)
                        end
                    end
                end
            end
        end
    end
    i = i + 3 + l
end

for _, b in ipairs(fbuckets)
do
    table.sort(b)
end

html.print("const n = null;")
html.write("const p=[")
for _, b in ipairs(fbuckets)
do
    if #b > 0 then
        local l = b[1 + math.floor(#b * 0.50)]
        local m = b[1 + math.floor(#b * 0.95)]
        local h = b[#b]
        html.write(l .. "," .. (m-l) .. "," .. (h-m) .. ",")
    end
    html.write("n,")
end
html.print("n];")

html.print("const yscale = " .. (-cheight / (max_sig - min_sig) / 4) .. ";")
html.print([[
    const bcolors = [ "red", "yellow", "mediumpurple" ];
    let xcursor = 0;
    let ycursor = 0;
    let ccursor = 0;
    for (let i = 0; i < p.length; i++) {
        let v = p[i];
        if (v === null) {
            xcursor += ]] .. (xscale * bw / 56) .. [[;
            ycursor = 0;
            ccursor = 0;
        }
        else {
            v *= yscale;
            ycursor += v;
            ctx.fillStyle = bcolors[ccursor];
            // ctx.fillRect(xcursor, ]] .. cheight .. [[ + ycursor, ]] .. (xscale * bw / 56) .. [[, -v);
            ctx.fillRect(xcursor, ]] .. cheight .. [[ + ycursor, 1, -v);
            ccursor++;
        }
    }
    ctx.strokeStyle = "rgba(0,0,0,0.5)";
    ctx.fillStyle = "black";
    ctx.font = "bold 12px Arial";
    ctx.textAlign = "center";
    ctx.beginPath()
    for (let f = ]] .. start_freq .. [[; f <= ]] .. end_freq .. [[; f += 10) {
        const x = Math.floor((f - ]] .. start_freq .. [[) * ]] .. xscale .. [[);
        ctx.moveTo(x, 0);
        ctx.lineTo(x, ]] .. (cheight - 20) .. [[);
        ctx.fillText("" + freq2chan(f), x, ]] .. cheight - 4 .. [[);
    }
    ctx.stroke();
    ctx.textAlign = "left";
    ctx.strokeStyle = "rgba(0,0,0,0.5)";
    ctx.beginPath();
    for (let snr = 60; snr >= 0; snr -= 10) {
        const y = ]] .. cheight .. [[ + yscale * (snr - ]] .. (min_sig - cnf) .. [[) * 4;
        ctx.moveTo(20, y);
        ctx.lineTo(]] .. cwidth .. [[, y);
        ctx.fillText("" + snr, 2, y);
    }
    ctx.stroke();
    </script></form>
]])

html.footer()
html.print("</body></html>")