Optimize Profinet with statistical analysis

				
					-- Listener to capture all Profinet traffic from the specified device
local profinet_listener = Listener.new("eth", "eth.src == b8:27:eb:f3:9a:b2 and pn_io")

-- Define the field to extract time delta between packets
local time_delta_displayed = Field.new("frame.time_delta_displayed")

-- Variables to store statistics
local total_time_delta = 0.0
local time_deltas = {}  -- Store each time delta for further statistical analysis
local min_time_delta = nil
local max_time_delta = nil
local packet_count = 0
local is_first_packet = true  -- Skip the first packet

-- Packet handler function
local function packet_handler(pinfo, tvb)
    local time_delta = time_delta_displayed()
    if time_delta then
        -- Skip the first packet
        if is_first_packet then
            is_first_packet = false
            return
        end

        local delta = tonumber(tostring(time_delta))
        total_time_delta = total_time_delta + delta
        packet_count = packet_count + 1
        table.insert(time_deltas, delta)

        if not min_time_delta or delta < min_time_delta then
            min_time_delta = delta
        end
        if not max_time_delta or delta > max_time_delta then
            max_time_delta = delta
        end
    end
end

-- Helper function to calculate the median
local function calculate_median(values)
    table.sort(values)
    local len = #values
    if len % 2 == 1 then
        return values[(len + 1) // 2]
    else
        return (values[len // 2] + values[len // 2 + 1]) / 2
    end
end

-- Helper function to calculate variance and standard deviation
local function calculate_variance_and_stddev(values, mean)
    local sum_sq_diff = 0
    for _, v in ipairs(values) do
        sum_sq_diff = sum_sq_diff + (v - mean) ^ 2
    end
    local variance = sum_sq_diff / #values
    return variance, math.sqrt(variance)
end

-- Reset function
function profinet_listener.reset()
    total_time_delta = 0.0
    time_deltas = {}
    min_time_delta = nil
    max_time_delta = nil
    packet_count = 0
    is_first_packet = true
    print("Profinet analysis started")
end

-- Draw function to calculate and print statistics
function profinet_listener.draw()
    if packet_count > 0 then
        local avg_time_delta = total_time_delta / packet_count
        local median_time_delta = calculate_median(time_deltas)
        local variance, stddev = calculate_variance_and_stddev(time_deltas, avg_time_delta)

        local max_deviation = nil
        local min_deviation = nil
        for _, delta in ipairs(time_deltas) do
            local deviation = math.abs(delta - avg_time_delta)
            if not max_deviation or deviation > max_deviation then
                max_deviation = deviation
            end
            if not min_deviation or deviation < min_deviation then
                min_deviation = deviation
            end
        end

        print("Profinet Time Delta Analysis Completed.")
        print("Total Packets: " .. packet_count)
        print("Minimum Time Delta: " .. min_time_delta .. " seconds")
        print("Maximum Time Delta: " .. max_time_delta .. " seconds")
        print("Average Time Delta: " .. avg_time_delta .. " seconds")
        print("Median Time Delta: " .. median_time_delta .. " seconds")
        print("Variance: " .. variance)
        print("Standard Deviation: " .. stddev)
        print("Maximum Deviation from Average: " .. max_deviation .. " seconds")
        print("Minimum Deviation from Average: " .. min_deviation .. " seconds")
    else
        print("No packets processed, unable to calculate time delta statistics.")
    end
end