Remove more bin.lua packings

nselib/amqp.lua

@@ -22,10 +22,10 @@
 
 -- Created 05/04/2011 - v0.1 - created by Sebastian Dragomir <velorien@gmail.com>
 
-local bin = require "bin"
 local match = require "match"
 local nmap = require "nmap"
 local stdnse = require "stdnse"
+local string = require "string"
 local table = require "table"
 _ENV = stdnse.module("amqp", stdnse.seeall);
 
@@ -93,7 +93,7 @@ AMQP = {
       end
       read = read + 1
 
-      tmp = select( 2, bin.unpack("C", tmp) )
+      tmp = string.unpack("B", tmp)
       status, key = self.amqpsocket:receive_buf(match.numbytes(tmp), true)
       if ( not(status) ) then
         return status, "ERROR: AMQP:handshake connection closed unexpectedly while reading key", nil
@@ -114,7 +114,7 @@ AMQP = {
 
         read = read + 4
         value = {}
-        tmp = select( 2, bin.unpack(">I", tmp) )
+        tmp = string.unpack(">I4", tmp)
         status, err, value = self:decodeTable(value, tmp)
         read = read + tmp
         table.insert(tbl, key .. ": ")
@@ -157,7 +157,7 @@ AMQP = {
     end
 
     read = read + 4
-    tmp = select( 2, bin.unpack(">I", tmp) )
+    tmp = string.unpack(">I4", tmp)
     status, value = self.amqpsocket:receive_buf(match.numbytes(tmp), true)
 
     if ( not(status) ) then
@@ -183,7 +183,7 @@ AMQP = {
       return status, "ERROR: AMQP:handshake connection closed unexpectedly while reading value for " .. key, nil, 0
     end
 
-    value = select( 2, bin.unpack("C", value) )
+    value = string.unpack("B", value)
     read = read + 1
 
     return true, nil, value == 0x01 and "YES" or "NO", read
@@ -210,14 +210,14 @@ AMQP = {
 
     -- check if the server rejected our proposed version
     if ( #tmp ~= 11 ) then
-      if ( #tmp == 8 and select( 2, bin.unpack(">I", tmp) ) == 0x414D5150 ) then
+      if ( #tmp == 8 and string.unpack(">I4", tmp) == 0x414D5150 ) then
         local vi, vii, v1, v2, v3, v4, found
-        _, vi = bin.unpack(">I", tmp, 5)
+        vi = string.unpack(">I4", tmp, 5)
         found = false
 
         -- check if we support the server's version
         for _, v in pairs( self.client_version_strings ) do
-          _, vii = bin.unpack(">I", v)
+          vii = string.unpack(">I4", v)
           if ( vii == vi ) then
             version = v
             found = true
@@ -239,7 +239,7 @@ AMQP = {
         end
 
         -- version unsupported
-        _, v1, v2, v3, v4 = bin.unpack(">CCCC", tmp, 5)
+        v1, v2, v3, v4 = string.unpack(">BBBB", tmp, 5)
         return false, ("ERROR: AMQP:handshake unsupported version (%d.%d.%d.%d)"):format( v1, v2, v3, v4 )
       else
         return false, ("ERROR: AMQP:handshake server might not be AMQP, received: %s"):format( tmp )
@@ -247,8 +247,7 @@ AMQP = {
     end
 
     -- parse frame header
-    local frametype, chnumber, framesize, method
-    _, frametype, chnumber, framesize, method = bin.unpack(">CSII", tmp)
+    local frametype, chnumber, framesize, method = string.unpack(">BI2I4I4", tmp)
     stdnse.debug1("frametype: %d, chnumber: %d, framesize: %d, method: %d", frametype, chnumber, framesize, method)
 
     if (frametype ~= 1) then
@@ -264,7 +263,7 @@ AMQP = {
     if ( not(status) ) then
       return status, "ERROR: AMQP:handshake connection closed unexpectedly while reading version"
     end
-    version = select( 2, bin.unpack(">S", tmp) )
+    version = string.unpack(">I2", tmp)
     self.protover = AMQP.versions[version]
 
     if ( not(self.protover) ) then
@@ -277,7 +276,7 @@ AMQP = {
       return status, "ERROR: AMQP:handshake connection closed unexpectedly while reading server properties size"
     end
 
-    local tablesize = select( 2, bin.unpack(">I", tmp) )
+    local tablesize = string.unpack(">I4", tmp)
     properties = {}
     status, err, properties = self:decodeTable(properties, tablesize)
 

nselib/mqtt.lua

@@ -1,4 +1,3 @@
-local bin = require "bin"
 local comm = require "comm"
 local match = require "match"
 local nmap = require "nmap"
@@ -215,7 +214,7 @@ Comm = {
       length = length .. chunk
 
       -- If the byte has the continuation bit cleared, stop receiving.
-      local _, byte = bin.unpack("C", chunk)
+      local byte = string.unpack("B", chunk)
       if byte < 128 then
         break
       end
@@ -302,10 +301,10 @@ Comm = {
     assert(pos < #buf)
 
     -- Parse the type and flags of the control packet's fixed header.
-    local pos, type_and_flags = bin.unpack("C", buf, pos)
-    if not pos then
+    if #buf - pos + 1 < 1 then
       return false, "Failed to parse control packet."
     end
+    local type_and_flags, pos = string.unpack("B", buf, pos)
 
     -- Parse the remaining length.
     local pos, length = MQTT.length_parse(buf, pos)
@@ -371,7 +370,7 @@ Comm = {
   -- @return Unique identifier for a packet.
   packet_identifier = function(self)
     self.packet_id = self.packet_id + 1
-    local num = bin.pack(">S", self.packet_id)
+    local num = string.pack(">I2", self.packet_id)
     return num
   end,
 }
@@ -533,7 +532,7 @@ MQTT.packet["CONNECT"].build = function(options)
     protocol_level = 4
   end
   assert(type(protocol_level) == "number")
-  head = head .. bin.pack("C", protocol_level)
+  head = head .. string.pack("B", protocol_level)
 
   -- 3.1.3.1 Client Identifier
   local client_id = options.client_id
@@ -585,13 +584,13 @@ MQTT.packet["CONNECT"].build = function(options)
     tail = tail .. MQTT.utf8_build(options.password)
   end
 
-  head = head .. bin.pack("C", cflags)
+  head = head .. string.pack("B", cflags)
 
   -- 3.1.2.10 Keep Alive
   if not options.keep_alive_secs then
     options.keep_alive_secs = 30
   end
-  head = head .. bin.pack(">S", options.keep_alive_secs)
+  head = head .. string.pack(">I2", options.keep_alive_secs)
 
   return true, MQTT.fixed_header(1, 0x0, head .. tail)
 end
@@ -622,7 +621,7 @@ MQTT.packet["CONNACK"].parse = function(fhflags, buf)
 
   -- 3.2.2.1 Connect Acknowledge Flags
   local res = {["type"] = "CONNACK"}
-  local _, caflags, crcode = bin.unpack("CC", buf)
+  local caflags, crcode = string.unpack("BB", buf)
 
   -- 3.2.2.2 Session Present
   res.session_present = ((caflags & 0x01) == 1)
@@ -656,10 +655,8 @@ end
 MQTT.packet["SUBSCRIBE"].build = function(options)
   assert(type(options) == "table")
 
-  local pkt = ""
-
   -- 3.8.2 Variable header
-  pkt = pkt .. options.packet_id
+  local pkt = {options.packet_id}
 
   for key, val in pairs(options.filters) do
     local name = val.filter
@@ -673,11 +670,11 @@ MQTT.packet["SUBSCRIBE"].build = function(options)
     assert(qos >= 0)
     assert(qos <= 2)
 
-    pkt = pkt .. MQTT.utf8_build(name)
-    pkt = pkt .. bin.pack("C", qos)
+    pkt[#pkt+1] = MQTT.utf8_build(name)
+    pkt[#pkt+1] = string.pack("B", qos)
   end
 
-  return true, MQTT.fixed_header(8, 0x2, pkt)
+  return true, MQTT.fixed_header(8, 0x2, table.concat(pkt))
 end
 
 --- Parse an MQTT SUBACK control packet.
@@ -708,14 +705,14 @@ MQTT.packet["SUBACK"].parse = function(fhflags, buf)
   if length < 2 then
     return false, ("Failed to parse SUBACK packet, too short.")
   end
-  local pos, packet_id = bin.unpack(">S", buf)
+  local packet_id, pos = string.unpack(">I2", buf)
   res.packet_id = packet_id
 
   -- 3.9.3 Payload
   local code
   local codes = {}
   while pos <= length do
-    pos, code = bin.unpack("C", buf, pos)
+    code, pos = string.unpack("B", buf, pos)
     if code == 0x00 then
       table.insert(codes, {["success"] = true, ["max_qos"] = 0})
     elseif code == 0x01 then
@@ -769,10 +766,10 @@ MQTT.packet["PUBLISH"].parse = function(fhflags, buf)
 
   -- 3.3.2.2 Packet Identifier
   if qos == 1 or qos == 2 then
-    pos, val = bin.unpack(">S", buf, pos)
-    if not pos then
-      return false, val
+    if #buf - pos + 1 < 2 then
+      return false, "packet truncated"
     end
+    val, pos = string.unpack(">I2", buf, pos)
     res.packet_id = val
   end
 
@@ -814,7 +811,7 @@ MQTT.length_build = function(num)
     if num > 0 then
       byte = byte | 0x80
     end
-    field[#field+1] = bin.pack("C", byte)
+    field[#field+1] = string.pack("B", byte)
   until num == 0
 
   -- This field has a limit on its length in binary form.
@@ -854,7 +851,7 @@ MQTT.length_parse = function(buf, pos)
     if pos > #buf then
       return false, "Reached end of buffer before variable-length numeric field was parsed."
     end
-    pos, byte = bin.unpack("C", buf, pos)
+    byte, pos = string.unpack("B", buf, pos)
     num = num + (byte & 0x7F) * multiplier
     if offset > 3 then
       return false, "Buffer contained an invalid variable-length numeric field."
@@ -889,7 +886,7 @@ end
 MQTT.utf8_build = function(str)
   assert(type(str) == "string")
 
-  return bin.pack(">P", str)
+  return string.pack(">s2", str)
 end
 
 --- Parse a UTF-8 string in MQTT's length-prefixed format.
@@ -918,12 +915,12 @@ MQTT.utf8_parse = function(buf, pos)
     return false, ("Buffer at position %d has no space for a UTF-8 length-prefixed string."):format(pos)
   end
 
-  local _, str_length = bin.unpack(">S", buf, pos)
+  local str_length = string.unpack(">I2", buf, pos)
   if pos + 1 + str_length > buf_length then
     return false, ("Buffer at position %d has no space for a %d-byte UTF-8 string."):format(pos, str_length)
   end
 
-  return bin.unpack(">P", buf, pos)
+  return string.unpack(">s2", buf, pos)
 end
 
 --- Prefix the body of an MQTT packet with a fixed header.
@@ -944,7 +941,7 @@ MQTT.fixed_header = function(num, flags, pkt)
   -- 2.2.2 Flags
   local hdr = (num << 4) | flags
 
-  return bin.pack("C", hdr) .. MQTT.length_build(#pkt) .. pkt
+  return string.pack("B", hdr) .. MQTT.length_build(#pkt) .. pkt
 end
 
 -- Skip unit tests unless we're explicitly testing.

nselib/ndmp.lua

@@ -4,11 +4,11 @@
 -- @author Patrik Karlsson <patrik@cqure.net>
 --
 
-local bin = require "bin"
 local match = require "match"
 local nmap = require "nmap"
 local os = require "os"
 local stdnse = require "stdnse"
+local string = require "string"
 local table = require "table"
 _ENV = stdnse.module("ndmp", stdnse.seeall)
 
@@ -50,7 +50,7 @@ NDMP = {
     -- @return fh new instance of FragmentHeader class
     parse = function(data)
       local fh = NDMP.FragmentHeader:new()
-      local _, tmp = bin.unpack(">I", data)
+      local tmp = string.unpack(">I4", data)
       fh.length = (tmp & 0x7fffffff)
       fh.last= (tmp >> 31)
       return fh
@@ -64,7 +64,7 @@ NDMP = {
         tmp = 0x80000000
       end
       tmp = tmp + self.length
-      return bin.pack(">I", tmp)
+      return string.pack(">I4", tmp)
     end,
 
   },
@@ -94,15 +94,14 @@ NDMP = {
     -- @return hdr new instance of Header
     parse = function(data)
       local hdr = NDMP.Header:new()
-      local pos
-      pos, hdr.seq, hdr.time, hdr.type, hdr.msg, hdr.reply_seq, hdr.error = bin.unpack(">IIIIII", data)
+      hdr.seq, hdr.time, hdr.type, hdr.msg, hdr.reply_seq, hdr.error = string.unpack(">I4I4I4I4I4I4", data)
       return hdr
     end,
 
     -- Serializes the instance to an opaque string
     -- @return str string containing the serialized class instance
     __tostring = function(self)
-      return bin.pack(">IIIIII", self.seq, self.time, self.type, self.msg, self.reply_seq, self.error)
+      return string.pack(">I4I4I4I4I4I4", self.seq, self.time, self.type, self.msg, self.reply_seq, self.error)
     end,
 
   },
@@ -137,7 +136,7 @@ NDMP.Message.ConfigGetServerInfo = {
     msg.data = data:sub(NDMP.Header.size + 1)
 
     msg.serverinfo = {}
-    local pos, err = bin.unpack(">I", msg.data)
+    local err, pos = string.unpack(">I4", msg.data)
     pos, msg.serverinfo.vendor = Util.parseString(msg.data, pos)
     pos, msg.serverinfo.product = Util.parseString(msg.data, pos)
     pos, msg.serverinfo.version = Util.parseString(msg.data, pos)
@@ -177,7 +176,7 @@ NDMP.Message.ConfigGetHostInfo = {
     msg.data = data:sub(NDMP.Header.size + 1)
 
     msg.hostinfo = {}
-    local pos, err = bin.unpack(">I", msg.data)
+    local err, pos = string.unpack(">I4", msg.data)
     pos, msg.hostinfo.hostname = Util.parseString(msg.data, pos)
     pos, msg.hostinfo.ostype = Util.parseString(msg.data, pos)
     pos, msg.hostinfo.osver = Util.parseString(msg.data, pos)
@@ -216,18 +215,18 @@ NDMP.Message.ConfigGetFsInfo = {
     end
     msg.data = data:sub(NDMP.Header.size + 1)
 
-    local pos, err, count = bin.unpack(">II", msg.data)
+    local err, count, pos = string.unpack(">I4I4", msg.data)
     for i=1, count do
       local item = {}
-      pos, item.invalid = bin.unpack(">I", msg.data, pos)
+      item.invalid, pos = string.unpack(">I4", msg.data, pos)
       pos, item.fs_type = Util.parseString(msg.data, pos)
       pos, item.fs_logical_device = Util.parseString(msg.data, pos)
       pos, item.fs_physical_device = Util.parseString(msg.data, pos)
-      pos, item.total_size = bin.unpack(">L", msg.data, pos)
-      pos, item.used_size = bin.unpack(">L", msg.data, pos)
-      pos, item.avail_size = bin.unpack(">L", msg.data, pos)
-      pos, item.total_inodes = bin.unpack(">L", msg.data, pos)
-      pos, item.used_inodes = bin.unpack(">L", msg.data, pos)
+      item.total_size,
+      item.used_size,
+      item.avail_size,
+      item.total_inodes,
+      item.used_inodes, pos = string.unpack(">I8I8I8I8I8", msg.data, pos)
       pos, item.fs_env = Util.parseString(msg.data, pos)
       pos, item.fs_status = Util.parseString(msg.data, pos)
       table.insert(msg.fsinfo, item)
@@ -271,7 +270,7 @@ NDMP.Message.UnhandledMessage = {
 Util = {
 
   parseString = function(data, pos)
-    local pos, str = bin.unpack(">a", data, pos)
+    local str, pos = string.unpack(">s4", data, pos)
     local pad = ( 4 - ( #str % 4 ) ~= 4 ) and 4 - ( #str % 4 ) or 0
     return pos + pad, str
 

nselib/sslv2.lua

@@ -6,10 +6,10 @@
 -- @author Daniel Miller
 
 local stdnse = require "stdnse"
-local bin = require "bin"
 local table = require "table"
 local nmap = require "nmap"
 local sslcert = require "sslcert"
+local string = require "string"
 local rand = require "rand"
 _ENV = stdnse.module("sslv2", stdnse.seeall)
 
@@ -119,7 +119,7 @@ local function read_header(buffer, i)
   end
 
   local len
-  i, len = bin.unpack(">S", buffer, i)
+  len, i = string.unpack(">I2", buffer, i)
   local msb = (len & 0x8000) == 0x8000
   local header_length, record_length, padding_length, is_escape
   if msb then
@@ -134,7 +134,7 @@ local function read_header(buffer, i)
     end
     record_length = len & 0x3fff
     is_escape = not not (len & 0x4000)
-    i, padding_length = bin.unpack("C", buffer, i)
+    padding_length, i = string.unpack("B", buffer, i)
   end
 
   return i, {
@@ -157,20 +157,20 @@ function record_read(buffer, i)
     return i, nil
   end
 
-  i, h.message_type = bin.unpack("C", buffer, i)
+  h.message_type, i = string.unpack("B", buffer, i)
 
   if h.message_type == SSL_MESSAGE_TYPES.SERVER_HELLO then
-    local j, SID_hit, certificate_type, ssl_version, certificate_len, ciphers_len, connection_id_len = bin.unpack(">CCSSSS", buffer, i)
-    local j, certificate = bin.unpack("A" .. certificate_len, buffer, j)
+    local SID_hit, certificate_type, ssl_version, certificate_len, ciphers_len, connection_id_len, j = string.unpack(">BBI2I2I2I2", buffer, i)
+    local certificate, j = string.unpack("c" .. certificate_len, buffer, j)
     local ciphers_end = j + ciphers_len
     local ciphers = {}
     while j < ciphers_end do
       local cipher
-      j, cipher = bin.unpack("A3", buffer, j)
+      cipher, j = string.unpack("c3", buffer, j)
       local cipher_name = SSL_CIPHERS[cipher] and SSL_CIPHERS[cipher].str or ("0x" .. stdnse.tohex(cipher))
       ciphers[#ciphers+1] = cipher_name
     end
-    local j, connection_id = bin.unpack("A" .. connection_id_len, buffer, j)
+    local connection_id, j = string.unpack("c" .. connection_id_len, buffer, j)
 
     h.body = {
       cert_type = certificate_type,
@@ -180,7 +180,7 @@ function record_read(buffer, i)
     }
     i = j
   elseif h.message_type == SSL_MESSAGE_TYPES.ERROR and h.record_length == 3 then
-    local j, err = bin.unpack(">S", buffer, i)
+    local err, j = string.unpack(">I2", buffer, i)
     h.body = {
       error = SSL_ERRORS[err] or err
     }
@@ -188,7 +188,7 @@ function record_read(buffer, i)
   else
     -- TODO: Other message types?
     h.message_type = "encrypted"
-    local j, data = bin.unpack("A"..h.record_length, buffer, i)
+    local data, j = string.unpack("c"..h.record_length, buffer, i)
     h.body = {
       data = data
     }
@@ -209,9 +209,9 @@ function ssl_record (payload, pad_length)
     "SSL record too long")
   assert(pad_length < 256, "SSL record padding too long")
   if pad_length > 0 then
-    return bin.pack(">SCA", length, pad_length, payload)
+    return string.pack(">I2B", length, pad_length) .. payload
   else
-    return bin.pack(">SA", (length | 0x8000), payload)
+    return string.pack(">I2", length | 0x8000) .. payload
   end
 end
 
@@ -233,15 +233,14 @@ function client_hello (ciphers)
 
   local challenge = rand.random_string(16)
 
-  local ssl_v2_hello = bin.pack(">CSSSSAA",
+  local ssl_v2_hello = string.pack(">BI2I2I2I2",
     1, -- MSG-CLIENT-HELLO
     2, -- version: SSL 2.0
     #cipher_codes * 3, -- cipher spec length
     0, -- session ID length
-    #challenge, -- challenge length
-    table.concat(cipher_codes),
-    challenge
-    )
+    #challenge) -- challenge length
+  .. table.concat(cipher_codes)
+  .. challenge
 
   return ssl_record(ssl_v2_hello, 0)
 end
@@ -250,16 +249,15 @@ function client_master_secret(cipher_name, clear_key, encrypted_key, key_arg)
   local key_arg = key_arg or ""
   local ck = SSL_CIPHER_CODES[cipher_name] or cipher_name
   assert(#ck == 3, "Unknown cipher in client_master_secret")
-  return ssl_record( bin.pack(">CASSSAAA",
-    SSL_MESSAGE_TYPES.CLIENT_MASTER_KEY,
-    ck,
-    #clear_key,
-    #encrypted_key,
-    #key_arg,
-    clear_key,
-    encrypted_key,
-    key_arg
-    ), 0)
+  return ssl_record( string.pack(">Bc3I2I2I2",
+      SSL_MESSAGE_TYPES.CLIENT_MASTER_KEY,
+      ck,
+      #clear_key,
+      #encrypted_key,
+      #key_arg)
+    .. clear_key
+    .. encrypted_key
+    .. key_arg, 0)
 end
 
 local function read_atleast(s, n)

nselib/xdmcp.lua

@@ -4,10 +4,10 @@
 --
 -- @author Patrik Karlsson <patrik@cqure.net>
 
-local bin = require "bin"
 local ipOps = require "ipOps"
 local nmap = require "nmap"
 local stdnse = require "stdnse"
+local string = require "string"
 local table = require "table"
 _ENV = stdnse.module("xdmcp", stdnse.seeall)
 
@@ -42,17 +42,19 @@ Packet = {
     -- Parses data based on which a new object is instantiated
     -- @param data opaque string containing data received over the wire
     -- @return hdr instance of class
+    -- @return pos position in the string where parsing left off
     parse = function(data)
-      local pos, hdr = nil, Packet.Header:new()
-      pos, hdr.version, hdr.opcode, hdr.length = bin.unpack(">SSS", data)
-      return hdr
+      local hdr = Packet.Header:new()
+      local pos
+      hdr.version, hdr.opcode, hdr.length, pos = string.unpack(">I2I2I2", data)
+      return hdr, pos
     end,
 
     -- Converts the instance to an opaque string
     -- @return str string containing the instance
     __tostring = function(self)
       assert(self.length, "No header length was supplied")
-      return bin.pack(">SSS", self.version, self.opcode, self.length)
+      return string.pack(">I2I2I2", self.version, self.opcode, self.length)
     end,
   },
 
@@ -76,12 +78,14 @@ Packet = {
     -- Converts the instance to an opaque string
     -- @return str string containing the instance
     __tostring = function(self)
-      local data = tostring(self.header)
-      data = data .. bin.pack("C", #self.authnames)
+      local data = {
+        tostring(self.header),
+        string.pack("B", #self.authnames),
+      }
       for _, name in ipairs(self.authnames) do
-        data = data .. bin.pack(">P", name)
+        data[#data+1] = string.pack(">s2", name)
       end
-      return data
+      return table.concat(data)
     end,
 
   },
@@ -117,11 +121,11 @@ Packet = {
     -- @return hdr instance of class
     parse = function(data)
       local willing = Packet[OpCode.WILLING]:new()
-      willing.header = Packet.Header.parse(data)
+      local pos
+      willing.header, pos = Packet.Header.parse(data)
 
-      local pos = 7
-      pos, willing.authname, willing.hostname,
-      willing.status = bin.unpack("ppp", data, pos)
+      willing.authname, willing.hostname,
+      willing.status, pos = string.unpack("s1s1s1", data, pos)
       return willing
     end,
 
@@ -190,20 +194,22 @@ Packet = {
     -- Converts the instance to an opaque string
     -- @return str string containing the instance
     __tostring = function(self)
-      local data = bin.pack(">SC", self.disp_no, #self.conns)
+      local data = {
+        string.pack(">I2B", self.disp_no, #self.conns),
+      }
       for _, conn in ipairs(self.conns) do
-        data = data .. bin.pack(">S", conn.iptype)
+        data[#data+1] = string.pack(">I2", conn.iptype)
       end
-      data = data .. bin.pack("C", #self.conns)
+      data[#data+1] = string.pack("B", #self.conns)
       for _, conn in ipairs(self.conns) do
-        data = data .. bin.pack(">P", ipOps.ip_to_str(conn.ip))
+        data[#data+1] = string.pack(">s2", ipOps.ip_to_str(conn.ip))
       end
-      data = data .. bin.pack(">PP", self.auth_name, self.auth_data)
-      data = data .. bin.pack("C", #self.authr_names)
+      data[#data+1] = string.pack(">s2s2B", self.auth_name, self.auth_data, #self.authr_names)
       for _, authr in ipairs(self.authr_names) do
-        data = data .. bin.pack(">P", authr)
+        data[#data+1] = string.pack(">s2", authr)
       end
-      data = data .. bin.pack(">P", self.manf_id)
+      data[#data+1] = string.pack(">s2", self.manf_id)
+      data = table.concat(data)
       self.header.length = #data
 
       return tostring(self.header) .. data
@@ -239,10 +245,10 @@ Packet = {
     -- @return hdr instance of class
     parse = function(data)
       local accept = Packet[OpCode.ACCEPT]:new()
-      accept.header = Packet.Header.parse(data)
-      local pos = 7
-      pos, accept.session_id, accept.auth_name, accept.auth_data,
-      accept.authr_name, accept.authr_data = bin.unpack(">IPPPP", data, pos)
+      local pos
+      accept.header, pos = Packet.Header.parse(data)
+      accept.session_id, accept.auth_name, accept.auth_data,
+      accept.authr_name, accept.authr_data, pos = string.unpack(">I4s2s2s2s2", data, pos)
       return accept
     end,
 
@@ -270,7 +276,7 @@ Packet = {
     -- Converts the instance to an opaque string
     -- @return str string containing the instance
     __tostring = function(self)
-      local data = bin.pack(">ISP", self.session_id, self.disp_no, self.disp_class)
+      local data = string.pack(">I4I2s2", self.session_id, self.disp_no, self.disp_class)
       self.header.length = #data
       return tostring(self.header) .. data
     end,