Current File : //opt/imunify360-webshield/lualib/resty/websocket/protocol.lua
-- Copyright (C) Yichun Zhang (agentzh)
local bit = require "bit"
local ffi = require "ffi"
local byte = string.byte
local char = string.char
local sub = string.sub
local band = bit.band
local bor = bit.bor
local bxor = bit.bxor
local lshift = bit.lshift
local rshift = bit.rshift
--local tohex = bit.tohex
local tostring = tostring
local concat = table.concat
local rand = math.random
local type = type
local debug = ngx.config.debug
local ngx_log = ngx.log
local ngx_DEBUG = ngx.DEBUG
local ffi_new = ffi.new
local ffi_string = ffi.string
local ok, new_tab = pcall(require, "table.new")
if not ok then
new_tab = function (narr, nrec) return {} end
end
local _M = new_tab(0, 5)
_M.new_tab = new_tab
_M._VERSION = '0.10'
local types = {
[0x0] = "continuation",
[0x1] = "text",
[0x2] = "binary",
[0x8] = "close",
[0x9] = "ping",
[0xa] = "pong",
}
local str_buf_size = 4096
local str_buf
local c_buf_type = ffi.typeof("char[?]")
local function get_string_buf(size)
if size > str_buf_size then
return ffi_new(c_buf_type, size)
end
if not str_buf then
str_buf = ffi_new(c_buf_type, str_buf_size)
end
return str_buf
end
function _M.recv_frame(sock, max_payload_len, force_masking)
local data, err = sock:receive(2)
if not data then
return nil, nil, "failed to receive the first 2 bytes: " .. err
end
local fst, snd = byte(data, 1, 2)
local fin = band(fst, 0x80) ~= 0
-- print("fin: ", fin)
if band(fst, 0x70) ~= 0 then
return nil, nil, "bad RSV1, RSV2, or RSV3 bits"
end
local opcode = band(fst, 0x0f)
-- print("opcode: ", tohex(opcode))
if opcode >= 0x3 and opcode <= 0x7 then
return nil, nil, "reserved non-control frames"
end
if opcode >= 0xb and opcode <= 0xf then
return nil, nil, "reserved control frames"
end
local mask = band(snd, 0x80) ~= 0
if debug then
ngx_log(ngx_DEBUG, "recv_frame: mask bit: ", mask and 1 or 0)
end
if force_masking and not mask then
return nil, nil, "frame unmasked"
end
local payload_len = band(snd, 0x7f)
-- print("payload len: ", payload_len)
if payload_len == 126 then
local data, err = sock:receive(2)
if not data then
return nil, nil, "failed to receive the 2 byte payload length: "
.. (err or "unknown")
end
payload_len = bor(lshift(byte(data, 1), 8), byte(data, 2))
elseif payload_len == 127 then
local data, err = sock:receive(8)
if not data then
return nil, nil, "failed to receive the 8 byte payload length: "
.. (err or "unknown")
end
if byte(data, 1) ~= 0
or byte(data, 2) ~= 0
or byte(data, 3) ~= 0
or byte(data, 4) ~= 0
then
return nil, nil, "payload len too large"
end
local fifth = byte(data, 5)
if band(fifth, 0x80) ~= 0 then
return nil, nil, "payload len too large"
end
payload_len = bor(lshift(fifth, 24),
lshift(byte(data, 6), 16),
lshift(byte(data, 7), 8),
byte(data, 8))
end
if band(opcode, 0x8) ~= 0 then
-- being a control frame
if payload_len > 125 then
return nil, nil, "too long payload for control frame"
end
if not fin then
return nil, nil, "fragmented control frame"
end
end
-- print("payload len: ", payload_len, ", max payload len: ",
-- max_payload_len)
if payload_len > max_payload_len then
return nil, nil, "exceeding max payload len"
end
local rest
if mask then
rest = payload_len + 4
else
rest = payload_len
end
-- print("rest: ", rest)
local data
if rest > 0 then
data, err = sock:receive(rest)
if not data then
return nil, nil, "failed to read masking-len and payload: "
.. (err or "unknown")
end
else
data = ""
end
-- print("received rest")
if opcode == 0x8 then
-- being a close frame
if payload_len > 0 then
if payload_len < 2 then
return nil, nil, "close frame with a body must carry a 2-byte"
.. " status code"
end
local msg, code
if mask then
local fst = bxor(byte(data, 4 + 1), byte(data, 1))
local snd = bxor(byte(data, 4 + 2), byte(data, 2))
code = bor(lshift(fst, 8), snd)
if payload_len > 2 then
-- TODO string.buffer optimizations
local bytes = get_string_buf(payload_len - 2)
for i = 3, payload_len do
bytes[i - 3] = bxor(byte(data, 4 + i),
byte(data, (i - 1) % 4 + 1))
end
msg = ffi_string(bytes, payload_len - 2)
else
msg = ""
end
else
local fst = byte(data, 1)
local snd = byte(data, 2)
code = bor(lshift(fst, 8), snd)
-- print("parsing unmasked close frame payload: ", payload_len)
if payload_len > 2 then
msg = sub(data, 3)
else
msg = ""
end
end
return msg, "close", code
end
return "", "close", nil
end
local msg
if mask then
-- TODO string.buffer optimizations
local bytes = get_string_buf(payload_len)
for i = 1, payload_len do
bytes[i - 1] = bxor(byte(data, 4 + i),
byte(data, (i - 1) % 4 + 1))
end
msg = ffi_string(bytes, payload_len)
else
msg = data
end
return msg, types[opcode], not fin and "again" or nil
end
local function build_frame(fin, opcode, payload_len, payload, masking)
-- XXX optimize this when we have string.buffer in LuaJIT 2.1
local fst
if fin then
fst = bor(0x80, opcode)
else
fst = opcode
end
local snd, extra_len_bytes
if payload_len <= 125 then
snd = payload_len
extra_len_bytes = ""
elseif payload_len <= 65535 then
snd = 126
extra_len_bytes = char(band(rshift(payload_len, 8), 0xff),
band(payload_len, 0xff))
else
if band(payload_len, 0x7fffffff) < payload_len then
return nil, "payload too big"
end
snd = 127
-- XXX we only support 31-bit length here
extra_len_bytes = char(0, 0, 0, 0, band(rshift(payload_len, 24), 0xff),
band(rshift(payload_len, 16), 0xff),
band(rshift(payload_len, 8), 0xff),
band(payload_len, 0xff))
end
local masking_key
if masking then
-- set the mask bit
snd = bor(snd, 0x80)
local key = rand(0xffffffff)
masking_key = char(band(rshift(key, 24), 0xff),
band(rshift(key, 16), 0xff),
band(rshift(key, 8), 0xff),
band(key, 0xff))
-- TODO string.buffer optimizations
local bytes = get_string_buf(payload_len)
for i = 1, payload_len do
bytes[i - 1] = bxor(byte(payload, i),
byte(masking_key, (i - 1) % 4 + 1))
end
payload = ffi_string(bytes, payload_len)
else
masking_key = ""
end
return char(fst, snd) .. extra_len_bytes .. masking_key .. payload
end
_M.build_frame = build_frame
function _M.send_frame(sock, fin, opcode, payload, max_payload_len, masking)
-- ngx.log(ngx.WARN, ngx.var.uri, ": masking: ", masking)
if not payload then
payload = ""
elseif type(payload) ~= "string" then
payload = tostring(payload)
end
local payload_len = #payload
if payload_len > max_payload_len then
return nil, "payload too big"
end
if band(opcode, 0x8) ~= 0 then
-- being a control frame
if payload_len > 125 then
return nil, "too much payload for control frame"
end
if not fin then
return nil, "fragmented control frame"
end
end
local frame, err = build_frame(fin, opcode, payload_len, payload,
masking)
if not frame then
return nil, "failed to build frame: " .. err
end
local bytes, err = sock:send(frame)
if not bytes then
return nil, "failed to send frame: " .. err
end
return bytes
end
return _M
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