Software /
code /
prosody
File
net/websocket/frames.lua @ 11114:6a608ecb3471
Merge 0.11->trunk
author | Matthew Wild <mwild1@gmail.com> |
---|---|
date | Tue, 29 Sep 2020 15:30:48 +0100 |
parent | 10241:48f7cda4174d |
parent | 11112:bcc701377fe4 |
child | 11158:3a72cb126d6c |
line wrap: on
line source
-- Prosody IM -- Copyright (C) 2012 Florian Zeitz -- Copyright (C) 2014 Daurnimator -- -- This project is MIT/X11 licensed. Please see the -- COPYING file in the source package for more information. -- local softreq = require "util.dependencies".softreq; local random_bytes = require "util.random".bytes; local bit = require "util.bitcompat"; local band = bit.band; local bor = bit.bor; local bxor = bit.bxor; local lshift = bit.lshift; local rshift = bit.rshift; local unpack = table.unpack or unpack; -- luacheck: ignore 113 local t_concat = table.concat; local s_char= string.char; local s_pack = string.pack; local s_unpack = string.unpack; if not s_pack and softreq"struct" then s_pack = softreq"struct".pack; s_unpack = softreq"struct".unpack; end local function read_uint16be(str, pos) local l1, l2 = str:byte(pos, pos+1); return l1*256 + l2; end -- FIXME: this may lose precision local function read_uint64be(str, pos) local l1, l2, l3, l4, l5, l6, l7, l8 = str:byte(pos, pos+7); local h = lshift(l1, 24) + lshift(l2, 16) + lshift(l3, 8) + l4; local l = lshift(l5, 24) + lshift(l6, 16) + lshift(l7, 8) + l8; return h * 2^32 + l; end local function pack_uint16be(x) return s_char(rshift(x, 8), band(x, 0xFF)); end local function get_byte(x, n) return band(rshift(x, n), 0xFF); end local function pack_uint64be(x) local h = band(x / 2^32, 2^32-1); return s_char(get_byte(h, 24), get_byte(h, 16), get_byte(h, 8), band(h, 0xFF), get_byte(x, 24), get_byte(x, 16), get_byte(x, 8), band(x, 0xFF)); end if s_pack then function pack_uint16be(x) return s_pack(">I2", x); end function pack_uint64be(x) return s_pack(">I8", x); end end if s_unpack then function read_uint16be(str, pos) if type(str) ~= "string" then str, pos = str:sub(pos, pos+1), 1; end return s_unpack(">I2", str, pos); end function read_uint64be(str, pos) if type(str) ~= "string" then str, pos = str:sub(pos, pos+7), 1; end return s_unpack(">I8", str, pos); end end local function parse_frame_header(frame) if #frame < 2 then return; end local byte1, byte2 = frame:byte(1, 2); local result = { FIN = band(byte1, 0x80) > 0; RSV1 = band(byte1, 0x40) > 0; RSV2 = band(byte1, 0x20) > 0; RSV3 = band(byte1, 0x10) > 0; opcode = band(byte1, 0x0F); MASK = band(byte2, 0x80) > 0; length = band(byte2, 0x7F); }; local length_bytes = 0; if result.length == 126 then length_bytes = 2; elseif result.length == 127 then length_bytes = 8; end local header_length = 2 + length_bytes + (result.MASK and 4 or 0); if #frame < header_length then return; end if length_bytes == 2 then result.length = read_uint16be(frame, 3); elseif length_bytes == 8 then result.length = read_uint64be(frame, 3); end if result.MASK then result.key = { frame:byte(length_bytes+3, length_bytes+6) }; end return result, header_length; end -- XORs the string `str` with the array of bytes `key` -- TODO: optimize local function apply_mask(str, key, from, to) from = from or 1 if from < 0 then from = #str + from + 1 end -- negative indices to = to or #str if to < 0 then to = #str + to + 1 end -- negative indices local key_len = #key local counter = 0; local data = {}; for i = from, to do local key_index = counter%key_len + 1; counter = counter + 1; data[counter] = s_char(bxor(key[key_index], str:byte(i))); end return t_concat(data); end local function parse_frame_body(frame, header, pos) if header.MASK then return apply_mask(frame, header.key, pos, pos + header.length - 1); else return frame:sub(pos, pos + header.length - 1); end end local function parse_frame(frame) local result, pos = parse_frame_header(frame); if result == nil or #frame < (pos + result.length) then return nil, nil, result; end result.data = parse_frame_body(frame, result, pos+1); return result, pos + result.length; end local function build_frame(desc) local data = desc.data or ""; assert(desc.opcode and desc.opcode >= 0 and desc.opcode <= 0xF, "Invalid WebSocket opcode"); if desc.opcode >= 0x8 then -- RFC 6455 5.5 assert(#data <= 125, "WebSocket control frames MUST have a payload length of 125 bytes or less."); end local b1 = bor(desc.opcode, desc.FIN and 0x80 or 0, desc.RSV1 and 0x40 or 0, desc.RSV2 and 0x20 or 0, desc.RSV3 and 0x10 or 0); local b2 = #data; local length_extra; if b2 <= 125 then -- 7-bit length length_extra = ""; elseif b2 <= 0xFFFF then -- 2-byte length b2 = 126; length_extra = pack_uint16be(#data); else -- 8-byte length b2 = 127; length_extra = pack_uint64be(#data); end local key = "" if desc.MASK then local key_a = desc.key if key_a then key = s_char(unpack(key_a, 1, 4)); else key = random_bytes(4); key_a = {key:byte(1,4)}; end b2 = bor(b2, 0x80); data = apply_mask(data, key_a); end return s_char(b1, b2) .. length_extra .. key .. data end local function parse_close(data) local code, message if #data >= 2 then code = read_uint16be(data, 1); if #data > 2 then message = data:sub(3); end end return code, message end local function build_close(code, message, mask) local data = pack_uint16be(code); if message then assert(#message<=123, "Close reason must be <=123 bytes"); data = data .. message; end return build_frame({ opcode = 0x8; FIN = true; MASK = mask; data = data; }); end return { parse_header = parse_frame_header; parse_body = parse_frame_body; parse = parse_frame; build = build_frame; parse_close = parse_close; build_close = build_close; };