README.md

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+names_per_ip
+============
+
+A mod for Minetest to stop annoyed kids
+
+It will limit the accounts to 2 (+3 if the player is whitelisted) per IP and delete IP history.
+
+Initial mod creator: Krock
+
+License: CC0
+
+Depends: nothing
+
+Chat commands
+-------------
+
+```
+/ipnames
+	whois <name>	-> Gets all accounts of <name>
+	list		-> Lists all exceptions/whitelist entries (players which can have "unlimited" accounts)
+	ignore <name>	-> Adds an exception/whitelist entry for <name>
+	unignore <name>	-> Removes an exception/whitelist entry for <name>
+```

functions.lua

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+-- WARNING: ipnames.command_* are reserved for chat commands!
+
+function ipnames.command_list(name)
+	local names = {} -- faster than string concat
+	for k, v in pairs(ipnames.whitelist) do
+		if v then
+			names[#names + 1] = k
+		end
+	end
+	return true, "All exceptions: " .. table.concat(names, ", ")
+end
+
+function ipnames.command_whois(name, param)
+	if not ipnames.data[param] then
+		return false, "The player '" .. param .. "' did not join yet."
+	end
+	
+	local ip = ipnames.data[param][1]
+	local names = ""
+	for k, v in pairs(ipnames.data) do
+		if v[1] == ip then
+			names = names .. " " .. k
+		end
+	end
+	return true, "Following players share an IP: " .. names
+end
+
+function ipnames.command_ignore(name, param)
+	if not ipnames.data[param] then
+		return false, "The player '" .. param .. "' did not join yet."
+	end
+	
+	ipnames.whitelist[param] = true
+	ipnames.save_whitelist()
+	return true, "Added '" .. param .. "' to the name whitelist."
+end
+
+function ipnames.command_unignore(name, param)
+	if not ipnames.whitelist[param] then
+		return false, "The player '" .. param .. "' is not on the whitelist."
+	end
+	
+	ipnames.whitelist[param] = nil
+	ipnames.save_whitelist()
+	return true, "Removed '" .. param .. "' from the name whitelist."
+end
+
+ipnames.is_registered = minetest.player_exists
+	or function(name)
+		-- 0.4.x support: If you get a nil error here -> update Minetest
+		return minetest.auth_table[name]
+	end
+
+-- TODO: Use mod storage
+function ipnames.load_data()
+	local file = io.open(ipnames.file, "r")
+	if not file then
+		return
+	end
+	local t = os.time()
+	for line in file:lines() do
+		local data = line:split("|")
+		if #data >= 2 then
+			-- Ignore players which were removed (according to auth)
+			local player_exists = ipnames.is_registered(data[1])
+
+			if player_exists then
+				data[3] = tonumber(data[3]) or 0
+				-- Remove IP after 2 weeks: Expired
+				if data[3] > 0 and t - data[3] > (3600 * 24 * 14) then
+					player_exists = false
+				end
+			end
+			if player_exists then
+				ipnames.data[data[1]] = {data[2], data[3]}
+			end
+		end
+	end
+	io.close(file)
+end
+
+function ipnames.save_data()
+	if not ipnames.changes then
+		return
+	end
+	ipnames.changes = false
+
+	local contents = {} -- faster than string concat
+	for k, v in pairs(ipnames.data) do
+		v[2] = v[2] or os.time()
+		contents[#contents + 1] = k.."|"..v[1].."|"..v[2]
+	end
+	minetest.safe_file_write(ipnames.file, table.concat(contents, "\n"))
+end
+
+function ipnames.load_whitelist()
+	local file = io.open(ipnames.whitelist_file, "r")
+	if not file then
+		return
+	end
+	for line in file:lines() do
+		if line ~= "" then
+			ipnames.whitelist[line] = true
+		end
+	end
+	io.close(file)
+end
+
+function ipnames.save_whitelist()
+	local names = {} -- faster than string concat
+	for k, v in pairs(ipnames.whitelist) do
+		if v then
+			names[#names + 1] = k
+		end
+	end
+	minetest.safe_file_write(ipnames.whitelist_file, table.concat(names, "\n"))
+end

init.lua

@@ -1,110 +1,123 @@
-minetest.register_privilege("whois", {
-    description = "Allows player to see other player IPs"})
-
 -- Created by Krock to stop mass-account-creators
--- License: WTFPL
+-- License: CC0
+
+if not minetest.safe_file_write then
+	error("[simple_protection] Your Minetest version is no longer supported."
+		.. " (version < 0.4.17)")
+end
 
 ipnames = {}
 ipnames.data = {}
-ipnames.tmp_data = {}
+ipnames.whitelist = {}
 ipnames.changes = false
-ipnames.file = minetest.get_worldpath().."/ipnames.txt"
+ipnames.file = minetest.get_worldpath().."/ipnames.data"
+ipnames.whitelist_file = minetest.get_worldpath().."/ipnames_whitelist.data"
 
-ipnames.name_per_ip_limit = tonumber(minetest.setting_get("max_names_per_ip")) or 5
+-- Limit 2 = maximal 2 accounts, the 3rd under the same IP gets blocked
+ipnames.name_per_ip_limit = tonumber(minetest.settings:get("max_names_per_ip")) or 2
+-- 2 + 3 = 5 accounts as limit for "ignored" players
+ipnames.extended_limit = 3
 
--- Get accounts self:
-minetest.register_chatcommand("whois", {
-	description = "Gets all players who have the same IP as the specified player",
-	privs = {whois = true},
+-- Interval where the IP list gets saved/updated
+ipnames.save_interval = 240
+
+dofile(minetest.get_modpath("names_per_ip").."/functions.lua")
+
+minetest.register_chatcommand("ipnames", {
+	description = "Get the features of names_per_ip",
+	privs = {ban=true},
 	func = function(name, param)
-		if not ipnames.data[param] then
-			minetest.chat_send_player(name, "The player \"" .. param .. "\" did not join yet.")
-			return
+		if param == "" then
+			return true,
+				"Available commands:\n" ..
+				"Get all accounts of <name>: /ipnames whois <name>\n" ..
+				"Show all whitelisted names: /ipnames list\n" ..
+				"Add/remove whitelist entry: /ipnames (un)ignore <name>"
+		end
+		if param == "list" then
+			return ipnames.command_list(name)
 		end
 
-		local ip = ipnames.data[param]
-		local names = "";
-		for k, v in pairs(ipnames.data) do
-			if v == ip then
-				if names ~= "" then
-					names = names .. ", " .. k
-				else
-					names = names .. " " .. k
-				end
-			end
+		-- Commands with two arguments
+		local args = param:split(" ")
+		if #args < 2 then
+			return false, "Error: Too few command arguments."
 		end
-		minetest.chat_send_player(name, "Players for IP address " .. ip .. ": " .. names)
-	end,
+
+		local func = ipnames["command_" .. args[1]]
+		if func then
+			return func(name, args[2])
+		end
+
+		return false, "Error: No known action for argument #1 ('"..args[1].."')"
+	end
 })
 
--- Get IP if player tries to join, ban if there are too much names per IP:
+-- Get IP if player tries to join, ban if there are too much names per IP
 minetest.register_on_prejoinplayer(function(name, ip)
-	-- Only stop new accounts:
-	ipnames.tmp_data[name] = ip
-	if not ipnames.data[name] then
-		local count = 1
-		local names = ""
-		for k, v in pairs(ipnames.data) do
-			if v == ip then
-				count = count + 1
-				names = names .. k .. ", "
-			end
-		end
+	-- Only stop new accounts
+	if ipnames.data[name] or ipnames.is_registered(name) then
+		return
+	end
 
-		if count <= ipnames.name_per_ip_limit and count > 1 then
-			minetest.log("action", name .. " now has " .. count .. " accounts. Other accounts: " .. names)
-		end
-
-		if count > ipnames.name_per_ip_limit then
-			ipnames.tmp_data[name] = nil
-			if tostring(ip) ~= "127.0.0.1" then
-				return ("\nYou exceeded the limit of accounts (" .. ipnames.name_per_ip_limit ..
-				").\nYou already have the following accounts:\n" .. names)
+	local names = {} -- faster than string concat
+	local count_bonus = nil
+	for k, v in pairs(ipnames.data) do
+		if v[1] == ip then
+			if not count_bonus and ipnames.whitelist[k] then
+				count_bonus = ipnames.extended_limit
 			end
+			names[#names + 1] = k
 		end
 	end
+
+	-- Return error message if too many accounts have been created
+	if #names > ipnames.name_per_ip_limit + (count_bonus or 0) then
+		return "\nYou exceeded the limit of accounts.\n" ..
+			"You already own the following accounts:\n" .. table.concat(names, ", ")
+	end
 end)
 
--- Save IP if player joined:
-minetest.register_on_joinplayer(function(player)
-	local name = player:get_player_name()
-	ipnames.data[name] = ipnames.tmp_data[name]
-	ipnames.tmp_data[name] = nil
+-- Save IP if player joined
+local function update_player_address(name, recursive)
+	local info = minetest.get_player_information(name)
+	local address = info and info.address
+
+	if not address then
+		minetest.log("warning", "[names_per_ip] minetest.get_player_information(\"" ..
+			name .. "\"): " .. dump(info) .. ". This is probably an engine bug.")
+		if not recursive then
+			-- Delay, hope it works next time
+			minetest.after(0.5, update_player_address, name, true)
+			return
+		end
+	end
+
+	ipnames.data[name] = {
+		address or "??",
+		os.time()
+	}
+
 	ipnames.changes = true
-	ipnames.save_data()
+end
+
+minetest.register_on_joinplayer(function(player)
+	update_player_address(player:get_player_name())
 end)
 
-function ipnames.load_data()
-	local file = io.open(ipnames.file, "r")
-	if not file then
-		return
-	end
-	for line in file:lines() do
-		if line ~= "" then
-			local data = line:split("|")
-			if #data >= 2 then
-				ipnames.data[data[1]] = data[2]
-			end
-		end
-	end
-	io.close(file)
+-- Data saving routine
+-- Save changes at a fixed interval
+local function save_data_job()
+	ipnames.save_data()
+	minetest.after(ipnames.save_interval, save_data_job)
 end
+minetest.after(ipnames.save_interval, save_data_job)
+minetest.register_on_shutdown(ipnames.save_data)
 
-function ipnames.save_data()
-	if not ipnames.changes then
-		return
-	end
-	ipnames.changes = false
-	local file = io.open(ipnames.file, "w")
-	for i, v in pairs(ipnames.data) do
-		if v ~= nil then
-			file:write(i .. "|" .. v .. "\n")
-		end
-	end
-	io.close(file)
-end
+-- Due to use of minetest.player_exists, the data loading must be delayed
+-- until ServerEnvironment is set up. register_on_mods_loaded is still too early.
+minetest.after(0, ipnames.load_data)
 
+ipnames.load_whitelist()
 
-minetest.register_on_shutdown(function() ipnames.save_data() end)
-
-minetest.after(3, function() ipnames.load_data() end)
+minetest.log("action", "[names_per_ip] loaded.")

mod.conf

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+name = names_per_ip