Netvolante DNS サービスを多段ルータの内側で利用する Lua スクリプト

netvolante-update.lua

-- netvolante-update.lua
-- Last Modified: 13 May 2014.

--[[

# brief

Netvolante DNS サービスを多段ルータの内側で利用する Lua スクリプトです。

VLAN ポートに一時的にグローバルIPを付与して Netvolante サービスに登録を行います。

## RT setting example

    # VLAN の設定を任意に行う(例では実質 VLAN 未使用と同じ)
    vlan port mapping lan1.1 vlan1
    vlan port mapping lan1.2 vlan1
    vlan port mapping lan1.3 vlan1
    vlan port mapping lan1.4 vlan1
    lan type lan1 port-based-option=divide-network
    
    # 一時的に使用するポート (lan1.4) と VLAN (vlan4) にグローバルIPを付与
    vlan port mapping lan1.4 vlan4
    ip vlan4 address AAA.BBB.CCC.DDD/EE
    
    # 自動更新をOFF
    netvolante-dns use vlan4 server=1 off
    
    # Netvolante サービスに登録
    netvolante-dns hostname host vlan4 server=1 HOSTNAME
    netvolante-dns go vlan4
    
    # 一時使用ポートと VLAN 情報を元に戻す
    no ip vlan4 address
    vlan port mapping lan1.4 vlan1
    
    # 自動起動を設定
    schedule at 1 startup * lua /lua/netvolante-update.lua

--]]


--########## configuration ##########

DEBUG = false

--# Aterm BL900HW web interface

ROUTER_INFO_URL = "http://192.168.0.1/index.cgi/info_main";
ROUTER_USERNAME = "adm"
ROUTER_PASSWORD = "password"

--# temporary port and vlan

TMP_PORT = "lan1.4"
TMP_VLAN = "vlan4"

--# restore vlan

RESTORE_VLAN = "vlan1"

--# restore vlan ip (empty -> delete ip)

RESTORE_VLAN_IP = ""
-- RESTORE_VLAN_IP = "192.168.100.1/24"

--# global ip watch interval (seconds)

WATCH_INTERVAL = 3600

--########## end configuration ##########


--[[ test functions
rt = {}
function rt.httprequest(...)
    local body = {}
    for line in io.lines("info.html") do body[#body + 1] = line end
    return { rtn1 = true, code = 200, body = table.concat(body, "\n") }
end
function rt.syslog( t, msg )
    print( "["..t.."]: "..msg )
end
function rt.command( cmd )
    return true, ""
end
function rt.sleep( sec )
    print( "rt.sleep("..sec..")" )
    os.exit()
end
--]]


function log_format( t, msg, ... )
    if ... then
        msg = string.format( msg, ... )
    end
    if DEBUG then
        print( "[" .. t .. "] " .. msg )
    else
        rt.syslog( t, "[LUA] netvolante-update.lua: " .. msg )
    end
end

function log_debug( msg, ... )
    log_format( "debug", msg, ... )
end

function log_info( msg, ... )
    log_format( "info", msg, ... )
end

function log_error( msg, ... )
    log_format( "info", "[ERR] " .. msg, ... )
end

function run_command( cmd, ... )
    if ... then
        cmd = string.format( cmd, ... )
    end
    log_debug( "[rt.command] %s", cmd )
    return cmd, rt.command( cmd )
end

function get_router_ip()
    log_debug( "GET %s", ROUTER_INFO_URL )
    local res = rt.httprequest({
        url = ROUTER_INFO_URL,
        method = "GET",
        auth_type = "basic",
        auth_name = ROUTER_USERNAME,
        auth_pass = ROUTER_PASSWORD,
    })
    if not ( res.rtn1 and res.code == 200 ) then
        log_error( "router cannot access (%s)", res.err )
        os.exit(1)
    end
    local s = { string.find( res.body, "<h2>WAN.-'WAN.-IP.->([0-9./]+)<" ) }
    log_debug( "router ip = %s", s[3] )
    return s[3]
end

function is_ip_changed( new_ip )
    local old_ip = os.getenv("GLOBALIP")
    if old_ip == new_ip then
        return false
    end
    return true
end

function update_netvolante( new_ip )
    local cmd, ret, msg
    cmd, ret, msg = run_command( "vlan port mapping %s %s", TMP_PORT, TMP_VLAN )
    if not ret then
        log_error( "\"%s\" -> \"%s\"", cmd, msg )
        return false
    end
    cmd, ret, msg = run_command( "ip %s address %s", TMP_VLAN, new_ip )
    if not ret then
        log_error( "\"%s\" -> \"%s\"", cmd, msg )
        return false
    end
    cmd, ret, msg = run_command( "netvolante-dns go %s", TMP_VLAN )
    if not ret then
        log_error( "\"%s\" -> \"%s\"", cmd, msg )
        return false
    end
    log_info( "netvolante-dns updated to %s", new_ip )
    run_command( "set GLOBALIP=%s", new_ip )
    if RESTORE_VLAN_IP and 0 < #RESTORE_VLAN_IP then
        run_command( "ip %s address %s", TMP_VLAN, RESTORE_VLAN_IP )
    else
        run_command( "no ip %s address", TMP_VLAN )
    end
    run_command( "vlan port mapping %s %s", TMP_PORT, RESTORE_VLAN )
    return true
end

function main()
    log_info( "starting" )
    while true do
        local new_ip = get_router_ip()
        if is_ip_changed(new_ip) then
            local ret = update_netvolante( new_ip )
            if not ret then os.exit(1) end
        end
        log_debug( "sleep %d sec...", WATCH_INTERVAL )
        rt.sleep( WATCH_INTERVAL )
    end
end

main()