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exports.name = "websocketutils"
exports.version = "0.0.1"
exports.author = "Niklas Kühtmann"
local bitmap = require('bitmap')
local bit = require('bit')
local bytemap = require('bytemap')
local b64 = require("base64")
local sha1 = require("sha1")
local string = require("string")
string.split = function(inputstr, sep)
if sep == nil then
sep = "%s"
end
local t = {}
local i = 1
for str in string.gmatch(inputstr, "([^" .. sep .. "]+)") do
t[i] = str
i = i + 1
end
return t
end
exports.disassemblePacket = function(buffer)
local bytemap = bytemap.fromString(buffer)
-- flag evaluation
local bitmap = bitmap.fromNumber(bytemap[1])
local fin = bitmap:isSet(1)
local rsv1 = bitmap:isSet(2)
rsv2 = bitmap:isSet(3)
rsv3 = bitmap:isSet(4)
local opcode = tonumber(bitmap[5] .. bitmap[6] .. bitmap[7] .. bitmap[8], 2)
-- message fragmentation check
if not fin then
print("WebSocket Error: Message Fragmentation not supported.")
return
end
-- client request close
if opcode == 8 then return 2 end
-- ping - pong
if opcode == 9 then
bitmap[8] = true
bitmap[7] = false
bytemap[1] = bitmap:toNumber()
return 1, bytemap:toString()
end
-- remove flags from bytemap
bytemap:popStart()
-- get packet size (needed for message fragmentation later on, sits inbetween so get it, why not)
-- need to know where to cut off anyway
local length = bytemap[1] - 128
bytemap:popStart()
if length == 126 then
length = bytemap:toNumber(1, 2)
bytemap:popStart(2)
elseif length == 127 then
length = bytemap:toNumber(1, 2, 3, 4, 5, 6, 7, 8)
bytemap:popStart(8)
end
-- get mask
local mask = {bytemap:get(1, 2, 3, 4)}
-- remove mask from bytemap
bytemap:popStart(4)
-- check if the tcp handler missed to push something
if length > #bytemap.bytes then return 3 end
-- finally decode and return
local ret = ""
bytemap:forEach(function(k, v)
local i = k % 4
ret = ret .. string.char(bit.bxor(mask[i > 0 and i or 4], v))
end)
return ret
end
exports.assemblePacket = function(buffer)
local flags = "10000001"
local bytemap = bytemap.new({tonumber(flags, 2), #buffer})
if bytemap[2] >= 65536 then
local length = bytemap[2]
for i = 10, 3, -1 do
bytemap[i] = bit.band(length, 0xFF)
length = bit.rshift(length, 8)
end
bytemap[2] = 127
elseif bytemap[2] >= 126 then
bytemap[4] = bit.band(bytemap[2], 0xFF)
bytemap[3] = bit.band(bit.rshift(bytemap[2], 8), 0xFF)
bytemap[2] = 126
end
for i = 1, #buffer do
bytemap:push(string.byte(buffer:sub(i, i)))
end
local ret = ""
bytemap:forEach(function(k, v)
ret = ret .. string.char(v)
end)
return ret
end
-- fixed crash when entering via http protocol on ip:port
exports.assembleHandshakeResponse = function(handshake)
local lines = handshake:split('\r\n')
local title = lines[1]
if lines[3] == "Connection: Upgrade" then
lines[1] = nil
local data = {}
for k, v in pairs(lines) do
if #v > 2 then
local line = v:split(": ")
data[line[1]] = line[2]
end
end
local responseKey = data["Sec-WebSocket-Key"] .. '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
responseKey = b64.encode(sha1.binary(responseKey))
return "HTTP/1.1 101 Switching Protocols\r\n" .. "Connection: Upgrade\r\n" .. "Upgrade: websocket\r\n" .. "Sec-WebSocket-Accept: " .. responseKey .. "\r\n" .. "\r\n"
else
return "HTTP/1.1 400 Bad Request\r\n"
end
end
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fixed crash when entering via http protocol on ip:port