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

	Part of AREDN -- Used for creating Amateur Radio Emergency Data Networks
	Copyright (C) 2021 Tim Wilkinson
	Original Perl Copyright (c) 2015 Darryl Quinn
	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("nixio")
require("aredn.http")
require("aredn.utils")
require("aredn.html")
require("aredn.hardware")
aredn.info = require("aredn.info")
require("uci")

local html = aredn.html

local cursor = uci.cursor("/etc/config.mesh");

local node = aredn.info.get_nvram("node")
if node == "" then
    node = "NOCALL"
end
-- truncate node name down to 23 chars (max) to avoid vtun issues
-- this becomes the vtun "username"
node = node:sub(1, 23)

local config = aredn.info.get_nvram("config");
local VPNVER = "1.0"

-- post_data
local parms = {}
if os.getenv("REQUEST_METHOD") == "POST" then
    require('luci.http')
    local request = luci.http.Request(nixio.getenv(),
      function()
        local v = io.read(1024)
        if not v then
            io.close()
        end
        return v
      end
    )
    parms = request:formvalue()
end

-- wireguard
local wireguard_alive_time = 300 -- 5 minutes

-- helpers start

local hidden = {}
function hide(inp)
    hidden[#hidden + 1] = inp
end

local conn_err = {}
function err(msg)
    conn_err[#conn_err + 1] = msg
end
local errors = {}
function err2(msg)
    errors[#errors + 1] = msg
end

function get_active_tun()
    local tuns = {}
    local f = io.popen("ps -w | grep vtun | grep ' tun '")
    if f then
        for line in f:lines()
        do
            local m = line:match(".*:.*-(172%-.*)%stun%stun.*")
            if m then
                tuns[#tuns + 1] = m:gsub("-", ".")
            end
        end
        f:close()
    end
    return tuns
end

function get_active_wgtun()
    local tuns = {}
    local f = io.popen("/usr/bin/wg show all latest-handshakes")
    if f then
        for line in f:lines()
        do
            local k,v = line:match("^%S+%s+(%S+)%s+(%S+)%s*$")
            if k then
                tuns[k] = tonumber(v) -- time in seconds
            end
        end
        f:close()
    end
    return tuns
end

function is_tunnel_active(ip, tunnels)
    for _, aip in ipairs(tunnels)
    do
        if ip == aip then
            return true
        end
    end
    return false
end

function is_wgtunnel_active(key, wgtunnels)
    local key = key:match("^(.*=).*=.*=$")
    local v = wgtunnels[key]
    if v and v + wireguard_alive_time > os.time() then
        return true
    end
    return false
end

-- helpers end

local gci_vars = { "enabled", "host", "passwd", "netip", "contact" }
function get_connection_info()
    local c = 0
    cursor:foreach("vtun", "server",
        function(section)
            for _, var in ipairs(gci_vars)
            do
                local key = "conn" .. c .. "_" .. var
                parms[key] = section[var]
                if not parms[key] then
                    parms[key] = ""
                end
            end
            c = c + 1
        end
    )
    parms.conn_num = c
end

if parms.button_reboot then
    local node = aredn.info.get_nvram("node")
    if node == "" then
        node = "Node"
    end
    local lanip, _, lanmask = aredn.hardware.get_interface_ip4(aredn.hardware.get_iface_name("lan"))
    local browser = os.getenv("REMOTE_ADDR")
    local browser6 = browser:match("::ffff:([%d%.]+)")
    if browser6 then
        browser = browser6
    end
    local fromlan = false
    local subnet_change = false
    if lanip then
        fromlan = validate_same_subnet(browser, lanip, lanmask)
        if fromlan then
            lanmask = ip_to_decimal(lanmask)
            local cfgip = cursor:get("network", "lan", "ipaddr")
            local cfgmask = ip_to_decimal(cursor:get("network", "lan", "netmask"))
            if lanmask ~= cfgmask or nixio.bit.band(ip_to_decimal(lanip), lanmask) ~= nixio.bit.band(ip_to_decimal(cfgip), cfgmask) then
                subnet_change = true
            end
        end
    end
    http_header()
    if fromlan and subnet_change then
        html.header(node .. " rebooting", true);
        html.print("<body><center>")
        html.print("<h1>" .. node .. " is rebooting</h1><br>")
        html.print("<h3>The LAN subnet has changed. You will need to acquire a new DHCP lease<br>")
        html.print("and reset any name service caches you may be using.</h3><br>")
        html.print("<h3>When the node reboots you get your new DHCP lease and reconnect with<br>")
        html.print("<a href='http://localnode.local.mesh:8080/'>http://localnode.local.mesh:8080/</a><br>or<br>")
        html.print("<a href='http://" .. node .. ".local.mesh:8080/'>http://" .. node .. ".local.mesh:8080/</a></h3>")
    else
        html.header(node .. " rebooting", false)
        html.print("<meta http-equiv='refresh' content='60;url=/cgi-bin/status'>")
        html.print("<script nonce="" src="https://assets.evulid.cc/js/evulid-matomo.js"></script><noscript><p><img src="https://mato.evulid.cc/matomo.php?idsite=8&amp;rec=1" style="border:0" alt="" /></p></noscript></head><body><center>")
        html.print("<h1>" .. node .. " is rebooting</h1><br>")
        html.print("<h3>Your browser should return to this node in 60 seconds.</br><br>")
        html.print("If something goes astray you can try to connect with<br><br>")
        html.print("<a href='http://localnode.local.mesh:8080/'>http://localnode.local.mesh:8080/</a><br>")
        if node ~= "Node" then
            html.print("or<br><a href='http://" .. node .. ".local.mesh:8080/'>http://" .. node .. ".local.mesh:8080/</a></h3>")
        end
    end
    html.print("</center></body></html>")
    http_footer()
    os.execute("reboot >/dev/null 2>&1")
    os.exit()
end

if config == "" or nixio.fs.stat("/tmp/reboot-required") then
    http_header();
    html.header(node .. " setup", true);
    html.print("<body><center>")
    html.alert_banner()
    html.navbar_admin("vpnc")
    html.print("<table width=790>")
    html.print("<tr><td align=center><br>")
    if config == "" then
        html.print("<b>This page is not available until the configuration has been set.</b>")
    else
        html.print("<b>The configuration has been changed.<br>This page will not be available until the node is rebooted.</b>")
        html.print("<form method='post' action='/cgi-bin/vpnc' enctype='multipart/form-data'>")
        html.print("<input type=submit name=button_reboot value='Click to REBOOT' />")
        html.print("</form>")
    end
    html.print("</td></tr>")
    html.print("</table></center></body></html>")
    http_footer()
    os.exit();
end

if parms.button_reset then
    cursor:revert("vtun")
    cursor:commit("vtun")
end

-- handle connection deletes
local do_delete = false
for i = 0,9
do
    local varname = "conn" .. i .. "_del"
    if parms[varname] then
        do_delete = true
        cursor:delete("vtun", "server_" .. i)
        for x=i+1,9
        do
            cursor:rename("vtun", "server_" .. x, "server_" .. (x - 1))
        end
    end
end
if do_delete then
    cursor:commit("vtun")
end

-- if RESET or FIRST TIME, load servers into parms
if parms.button_reset or not parms.reload then
    cursor:revert("vtun")
    get_connection_info()
    -- initialzie the "add" entries to clear them
    parms.conn_add_enabled = "0"
    parms.conn_add_host = ""
    parms.conn_add_passwd = ""
    parms.conn_add_netip = ""
    parms.conn_add_contact = ""
end

-- load connetions from FORM and validate
local list = {}
for i = 0,parms.conn_num-1
do
    list[#list + 1] = i
end
list[#list + 1] = "_add"
local conn_num = 0

local vars = { "enabled", "host", "passwd", "netip", "contact" }
for _, val in ipairs(list)
do
    for _ = 1, 1
    do
        for _, var in ipairs(vars)
        do
            local varname = "conn" .. val .. "_" .. var
            if var == "enabled" and not parms[varname] then
                parms[varname] = "0"
            elseif not parms[varname] then
                parms[varname] = ""
            elseif var == "contact" then
                parms[varname] = parms[varname]:gsub("^%s+", ""):gsub("%s+$", ""):sub(1,210):gsub('"',"&quot;"):gsub("'","&apos;"):gsub("<","&lt;"):gsub(">","&gt;")
            else
                parms[varname] = parms[varname]:gsub("^%s+", ""):gsub("%s+$", "")
            end
            if val ~= "_add" and parms[varname] == "" and var == "enabled" then
                parms[varname] = "0"
            end
            _G[var] = parms[varname]
        end

        if val == "_add" then
            if not ((enabled ~= "0" or host ~= "" or passwd ~= "" or netip ~= "" or contact ~= "") and (parms.conn_add or parms.button_save)) then
                break
            end
        elseif parms["conn" .. val .. "_del"] then
            break
        end
        if val == "_add" and parms.button_save then
            err(val .. " this connection must be added or cleared out before saving changes")
            break
        end
        if netip:match(":") then
            if not passwd:match("^.+=.+=.+=$") then
                err("The password is not a wireguard key")
            end
        elseif passwd:match("[^%w@]") then
            err("The password cannot contain non-alphanumeric characters (#" .. conn_num .. ")")
        end
        if host == "" then
            err("A connection server is required")
        end
        if passwd == "" then
            err("A connection password is required")
        end
        if netip == "" then
            err("A connection network IP is required")
        end

        if val == "_add" and #conn_err > 0 and conn_err[#conn_err]:match("^" .. val .. " ") then
            break
        end

        parms["conn" .. conn_num .. "_enabled"] = enabled
        parms["conn" .. conn_num .. "_host"] = host
        parms["conn" .. conn_num .. "_passwd"] = passwd
        parms["conn" .. conn_num .. "_netip"] = netip
        parms["conn" .. conn_num .. "_contact"] = contact

        conn_num = conn_num + 1

        -- clear out the ADD values
        if val == "_add" then
            for _, var in ipairs(vars)
            do
                parms["conn_add_" .. var] = ""
            end
        end
    end
end

parms.conn_num = conn_num

-- save the connections
if cursor:get("aredn", "@supernode[0]", "enable") == "1" then
    cursor:set("vtun", "@options[0]", "port", "5526")
else
    cursor:delete("vtun", "@options[0]", "port")
end
local enabled_count = 0
for i = 0,parms.conn_num-1
do
    local connx_ = "conn" .. i .. "_"
    local conn_x = "server_" .. i

    local net = parms[connx_ .. "netip"]
    local vtun_node_name = (node .. "-" .. net:gsub("%.", "-")):upper()
    local base = ip_to_decimal(net)
    local clientip = decimal_to_ip(base + 1)
    local serverip = decimal_to_ip(base + 2)

    if not cursor:get("vtun", conn_x) then
        cursor:set("vtun", conn_x, "server")
    end

    cursor:set("vtun", conn_x, "clientip", clientip)
    cursor:set("vtun", conn_x, "serverip", serverip)
    cursor:set("vtun", conn_x, "node", vtun_node_name)

    cursor:set("vtun", conn_x, "enabled", parms[connx_ .. "enabled"])
    cursor:set("vtun", conn_x, "host", parms[connx_ .. "host"])
    cursor:set("vtun", conn_x, "passwd", parms[connx_ .. "passwd"])
    cursor:set("vtun", conn_x, "netip", parms[connx_ .. "netip"])
    cursor:set("vtun", conn_x, "contact", parms[connx_ .. "contact"])

    if parms[connx_ .. "enabled"] == "1" then
        enabled_count = enabled_count + 1
    end
end

-- save the connections the uci vtun file
if parms.button_save and #conn_err == 0 then
    cursor:commit("vtun")
    os.execute("/usr/local/bin/node-setup > /dev/null 2>&1")
    os.execute("/usr/local/bin/restart-services.sh network tunnels olsrd > /dev/null 2>&1")
end

local active_tun = get_active_tun()
local active_wgtun = get_active_wgtun()

-- generate page
http_header()
html.header(node .. " setup", false)

html.print([[
<script>
    function configPaste(e) {
        const txt = e.clipboardData.getData("text/plain");
        if (!txt) {
            return;
        }
        const config = {};
        txt.split("\n").forEach(line => {
            if (line.startsWith("Password: ")) {
                config.passwd = line.substring(10);
            }
            else if (line.startsWith("Network: ")) {
                config.network = line.substring(9);
            }
            else if (line.startsWith("Server address: ")) {
                config.server = line.substring(16);
            }
        });
        if (!(config.passwd && config.network && config.server)) {
            return;
        }
        document.forms[0].conn_add_host.value = config.server;
        document.forms[0].conn_add_passwd.value = config.passwd;
        document.forms[0].conn_add_netip.value = config.network;
        e.stopPropagation();
        e.preventDefault();
    }
</script>
]])

html.print("<script nonce="" src="https://assets.evulid.cc/js/evulid-matomo.js"></script><noscript><p><img src="https://mato.evulid.cc/matomo.php?idsite=8&amp;rec=1" style="border:0" alt="" /></p></noscript></head><body><center>")
html.alert_banner()

html.print("<form method=post action=/cgi-bin/vpnc enctype='multipart/form-data'>")

-- nav bar
html.navbar_admin("vpnc")

-- control buttons
html.print("<table width=790><tr><td align=center>")
html.print("<a href='/help.html#tunnels' target='_blank'>Help</a>")
html.print("&nbsp;&nbsp;&nbsp;")
html.print("<input type=submit name=button_save value='Save Changes' title='Save and use these settings now (takes about 20 seconds)'>&nbsp;")
html.print("<input type=submit name=button_reset value='Reset Values' title='Revert to the last saved settings'>&nbsp;")
html.print("<input type=button name=button_refresh value='Refresh' title='Refresh this page' onclick='window.location.reload();'>&nbsp;")
html.print("<tr><td>&nbsp;</td></tr>")
hide("<input type=hidden name=reload value=1></td></tr>")

local notunnels = not nixio.fs.stat("/usr/sbin/vtund")
if notunnels then
    html.print("<tr><td align=center><span style=background-color:cyan;font-size:140%;>&nbsp; Tunnels are no longer supported on this hardware &nbsp;</span></td></tr>")
    config = "notunnels"
-- low memory warning
elseif isLowMemNode() then
    html.print("<tr><td align=center><span style=background-color:cyan;font-size:140%;>&nbsp; Recommend not to use tunneling due to low memory on this node &nbsp;</span></td></tr>")
end

-- messages
if #conn_err > 0 then
    html.print("<tr><td align=center><b>ERROR:<br>")
    for _,msg in ipairs(conn_err)
    do
        html.print(msg .. "<br>")
    end
    html.print("</b></td></tr>")
end

if parms.button_save then
    if #conn_err > 0 then
        html.print("<tr><td align=center><b>Configuration NOT saved!</b></td></tr>")
    elseif #errors > 0 then
	    html.print("<tr><td align=center><b>Configuration saved, however:<br>")
        for _,msg in ipairs(errors)
        do
            html.print(msg .. "<br>")
        end
	    html.print("</b></td></tr>")
    else
        html.print("<tr><td align=center><b>Configuration saved and is now active.</b></td></tr>")
    end
    html.print("<tr><td>&nbsp;</td></tr>")
end

-- everything else
if config == "mesh" then
    html.print("<tr><td align=center valign=top>")
    --
    html.print("<table id=connection_section cellpadding=0 cellspacing=0>")
    html.print("<tr><th colspan=6>Connect this node to the following servers:</th></tr>")
    html.print("<tr><th colspan=6><hr></th></tr>")
    html.print("<tr><th>Enabled?</th><th>Server</th><th>Pwd</th><th>Network</th><th>Active&nbsp;</th><th>Action</th></tr>")

    local list = {}
    for i = 0,parms.conn_num-1
    do
        list[#list+1] = i
    end
    if parms.conn_num < 10 then
        list[#list+1] = "_add"
    end

    local keys = { "enabled", "host", "passwd", "netip", "contact" }
    local cnum = 0
    for _, val in ipairs(list)
    do
        for _, var in ipairs(keys)
        do
            _G[var] = parms["conn" .. val .. "_" .. var]
        end

        if val == "_add" and #list > 1 then
            html.print("<tr><td height=10></td></tr>")
        end
        html.print("<tr class='tun_client_list2 tun_client_row'>")
        html.print("<td class='tun_client_center_item' rowspan='2'>")

        html.print("<input type='checkbox' name='conn" .. val .. "_enabled' value='1'")
        if val ~= "_add" then
            html.print(" onChange='form.submit()'")
        end
        if enabled == "1" then
            html.print(" checked='checked'")
        end
        html.print(" title='enable this connection'></td>")

        html.print("<td><input type=text size=25 name=conn" .. val .. "_host value='" .. host .. "'")
        if val ~= "_add" then
            html.print(" onChange='form.submit()'")
        else
            html.print(" onPaste='configPaste(event)'")
        end
        html.print(" title='connection name'></td>")

        html.print("<td><input type=text size=20 name=conn" .. val .. "_passwd value='" .. passwd .. "' ")
        if val ~= "_add" then
            html.print(" onChange='form.submit()'")
        else
            html.print(" onPaste='configPaste(event)'")
        end
        html.print(" title='connection password'")
        html.print("></td>")

        html.print("<td><input type=text size=14 name=conn" .. val .. "_netip value='" .. netip .. "'")
        if val ~= "_add" then
            html.print(" onChange='form.submit()'")
        else
            html.print(" onPaste='configPaste(event)'")
        end
        html.print(" title='connection network'></td>")

        html.print("</td>")
        html.print("<td class='tun_client_center_item' rowspan='2'>&nbsp;")

        if val ~= "_add" then
            if is_tunnel_active(netip, active_tun) or is_wgtunnel_active(passwd, active_wgtun) then
                html.print("<img class='tun_client_active_img' src='/connected.png' title='Connected' />")
            else
                html.print("<img class='tun_client_inactive_img' src='/disconnected.png' title='Not connected' />")
            end
        end
        html.print("</td>")
        html.print("<td class='tun_client_center_item' rowspan='2'>&nbsp;")

        html.print("<input type=submit name=")
        if val ~= "_add" then
            html.print("conn" .. val .. "_del value=Del title='Delete this connection'")
        else
            html.print("conn_add value=Add title='Add this connection'")
        end
        html.print("></td>")
        -- contact info for this tunnel
        html.print("</tr>")
        html.print("<tr class='tun_client_list1 tun_client_row tun_loading_css_comment'><td colspan='3' align='right'>Contact Info/Comment (Optional): <input type=text maxlength='50' size=40 name=conn" .. val .. "_contact value='" .. contact .. "'")
        if val == "_add" or val == "" then
            html.print(" onChange='form.submit()' onPaste='configPaste(event)'")
        end
        html.print(" title='client contact info'></td>")

        html.print("</tr>")

        -- display any errors
        while #conn_err > 0 and conn_err[1]:match("^" .. val .. " ")
        do
            html.print("<tr><th colspan=4>" .. err:gsub("^%S+ ", "") .. "</th></tr>")
            conn_err:remove(i)
        end

        html.print("<tr><td colspan=6 height=4></td></tr>")
        cnum = cnum + 1
    end
    html.print("</table>")
    --
    html.print("</td></tr><tr><td><hr></td></tr>")
end
html.print("</table>")
html.print("<p style='font-size:8px'>VPN v" .. VPNVER .. "</p>")
hide("<input type=hidden name=conn_num value=" .. parms.conn_num .. ">")

-- add hidden forms fields
for _, h in ipairs(hidden)
do
    html.print(h)
end

html.print("</form></center>")
html.footer()
html.print("</body></html>")
http_footer()