Modem-API

function getModem()
    local side = nil
    local sides = peripheral.getNames()

    local index = 1
    while sides[index]~= nil do
        if peripheral.getType(sides[index]) == "modem" then
            side = sides[index]
            do break end
        end
        index = index + 1
    end

    return side
end

function getRednetHosts(protocol)
    local hosts = nil
    if getModem() ~= nil then
        rednet.open(getModem())
        local hostsID = rednet.lookup(protocol)
        if hostsID ~= nil then
            for index = 1, hostsID[index] ~= nil, 1 do
                if hostsID[index] ~= os.getComputerID() then
                    rednet.send(hostsID[index], "name", protocol)
                    local result = {rednet.receive(protocol)}
                    hosts[index] = {result[1], result[2]}
                end
            end
        end
    end
    return hosts
end

function regeisterComputer(protocol, newName)
    os.setComputerLabel(newName)
    local hosts = getRednetHosts()
    if hosts ~= nil then
        for index = 1, hosts[index] ~= nil, 1 do
            if string.find(hosts[index][2], newName) then
                local number = string.sub(hosts[index][2], string.len(newName))
                print(number)
            end
        end
    end
end