Reorganise, move code to not be split between haproxy and src folder

src/lua/libs/utils.lua

@@ -0,0 +1,68 @@
+local _M = {}
+
+local sha = require("sha")
+local secret_bucket_duration = tonumber(os.getenv("BUCKET_DURATION"))
+local challenge_includes_ip = os.getenv("CHALLENGE_INCLUDES_IP")
+local tor_control_port_password = os.getenv("TOR_CONTROL_PORT_PASSWORD")
+
+-- generate the challenge hash/user hash
+function _M.generate_secret(context, salt, user_key, is_applet)
+
+	-- time bucket for expiry
+	local start_sec = core.now()['sec']
+	local bucket = start_sec - (start_sec % secret_bucket_duration)
+
+	-- optional IP to lock challenges/user_keys to IP (for clearnet or single-onion aka 99% of cases)
+	local ip = ""
+	if challenge_includes_ip == "1" then
+		ip = context.sf:src()
+	end
+
+	-- user agent to counter very dumb spammers
+	local user_agent = ""
+	if is_applet == true then
+		user_agent = context.headers['user-agent'] or {}
+		user_agent = user_agent[0] or ""
+	else
+		--note req_fhdr not req_hdr otherwise commas in useragent become a delimiter
+		user_agent = context.sf:req_fhdr('user-agent') or ""
+	end
+
+	return sha.sha3_256(salt .. bucket .. ip .. user_key .. user_agent)
+
+end
+
+-- split string by delimiter
+function _M.split(inputstr, sep)
+	local t = {}
+	for str in string.gmatch(inputstr, "([^"..sep.."]*)") do
+		table.insert(t, str)
+	end
+	return t
+end
+
+-- return true if hash passes difficulty
+function _M.checkdiff(hash, diff)
+	local i = 1
+	for j = 0, (diff-8), 8 do
+		if hash:sub(i, i) ~= "0" then
+			return false
+		end
+		i = i + 1
+	end
+	local lnm = tonumber(hash:sub(i, i), 16)
+	local msk = 0xff >> ((i*8)-diff)
+	return (lnm & msk) == 0
+end
+
+-- connect to the tor control port and instruct it to close a circuit
+function _M.send_tor_control_port(circuit_identifier)
+	local tcp = core.tcp();
+	tcp:settimeout(1);
+	tcp:connect("127.0.0.1", 9051);
+	-- not buffered, so we are better off sending it all at once
+	tcp:send('AUTHENTICATE "' .. tor_control_port_password .. '"\nCLOSECIRCUIT ' .. circuit_identifier ..'\n')
+	tcp:close()
+end
+
+return _M