(ANTAG) Adds NTNet DoS Traffic Generator

- Implements DoS traffic generator that is available via software downloads on emagged computers (computer emagging will be added separately)
- This generator sends DoS traffic to the NTNet relay. Amount of generated traffic is linked to connectivity (Wired: 5GQ/s, High Signal: 1GQ/s, Low Signal: 0.25GQ/s)
- NTNet relays dissipate this DoS traffic on their own (at 1GQ/s rate).
- Multiple devices running this program against one relay will have cumulative effect. For example, one wirelessly connected device would not be able to overload the relay, since it dissipates same amount of traffic as wireless device generates. On the other hand, two wirelessly connected devices would eventually result in overload and failure of relay.
- (D)DoS attacks may be stopped by manually shutting down the relay and reactivating it again
- DoS program will trigger an IDS(Intrusion Detection System) alert on execution, which will immediately show on the monitoring console. However, if IDS is disabled, only way to detect this is via the relay's UI (it will show increase in buffered traffic)
- Screenshots: http://i.imgur.com/q0gbWJm.png   http://i.imgur.com/NVobCWa.png     (Visual note: 1s and 0s in the UI change over time, amount of 1s is equivalent to approximate percentage completion of DoS attack)

code/modules/modular_computers/file_system/programs/antagonist/dos.dm

@@ -0,0 +1,103 @@
+/datum/computer_file/program/ntnet_dos
+	filename = "ntn_dos"
+	filedesc = "DoS Traffic Generator"
+	program_icon_state = "hostile"
+	size = 20
+	requires_ntnet = 1
+	available_on_ntnet = 0
+	available_on_syndinet = 1
+	nanomodule_path = /datum/nano_module/computer_dos/
+	var/obj/machinery/ntnet_relay/target = null
+	var/dos_speed = 0
+	var/error = ""
+	var/executed = 0
+
+/datum/computer_file/program/ntnet_dos/process_tick()
+	dos_speed = 0
+	switch(ntnet_status)
+		if(1)
+			dos_speed = NTNETSPEED_LOWSIGNAL * 10
+		if(2)
+			dos_speed = NTNETSPEED_HIGHSIGNAL * 10
+		if(3)
+			dos_speed = NTNETSPEED_ETHERNET * 10
+	if(target && executed)
+		target.dos_overload += dos_speed
+		if(target.is_operational())
+			target.dos_sources.Remove(src)
+			target = null
+			error = "Connection to destination relay lost."
+
+/datum/computer_file/program/ntnet_dos/kill_program(var/forced)
+	target.dos_sources.Remove(src)
+	target = null
+	executed = 0
+
+	..(forced)
+
+/datum/nano_module/computer_dos
+	name = "DoS Traffic Generator"
+
+/datum/nano_module/computer_dos/ui_interact(mob/user, ui_key = "main", var/datum/nanoui/ui = null, var/force_open = 1, var/datum/topic_state/state = default_state)
+	if(!ntnet_global)
+		return
+	var/datum/computer_file/program/ntnet_dos/PRG = program
+	var/list/data = list()
+	if(!istype(PRG))
+		return
+	data = PRG.get_header_data()
+
+	if(PRG.error)
+		data["error"] = PRG.error
+	else if(PRG.target && PRG.executed)
+		data["target"] = 1
+		data["speed"] = PRG.dos_speed
+
+		// This is mostly visual, generate some strings of 1s and 0s
+		// Probability of 1 is equal of completion percentage of DoS attack on this relay.
+		// Combined with UI updates this adds quite nice effect to the UI
+		var/percentage = PRG.target.dos_overload * 100 / PRG.target.dos_capacity
+		var/list/strings[0]
+		for(var/j, j<10, j++)
+			var/string = ""
+			for(var/i, i<20, i++)
+				string = "[string][prob(percentage)]"
+			strings.Add(string)
+		data["dos_strings"] = strings
+	else
+		var/list/relays[0]
+		for(var/obj/machinery/ntnet_relay/R in ntnet_global.relays)
+			relays.Add(R.uid)
+		data["relays"] = relays
+		data["focus"] = PRG.target ? PRG.target.uid : null
+
+	ui = nanomanager.try_update_ui(user, src, ui_key, ui, data, force_open)
+	if (!ui)
+		ui = new(user, src, ui_key, "ntnet_dos.tmpl", "DoS Traffic Generator", 400, 250, state = state)
+		ui.auto_update_layout = 1
+		ui.set_initial_data(data)
+		ui.open()
+		ui.set_auto_update(1)
+
+/datum/computer_file/program/ntnet_dos/Topic(href, href_list)
+	if(..())
+		return 1
+	if(href_list["PRG_target_relay"])
+		for(var/obj/machinery/ntnet_relay/R in ntnet_global.relays)
+			if("[R.uid]" == href_list["PRG_target_relay"])
+				target = R
+		return
+	if(href_list["PRG_reset"])
+		target.dos_sources.Remove(src)
+		target = null
+		executed = 0
+		error = ""
+		return
+	if(href_list["PRG_execute"])
+		if(target)
+			executed = 1
+			target.dos_sources.Add(src)
+			if(ntnet_global.intrusion_detection_enabled)
+				ntnet_global.add_log("IDS WARNING - Excess traffic flood targeting relay [target.uid] detected from device: [computer.network_card.get_network_tag()]")
+				ntnet_global.intrusion_detection_alarm = 1
+		return