Remove more bin.lua packings.

ibenrodriguez · Sep 22, 2018 · ff6b5b6 · ff6b5b6
1 parent e9addd7
commit ff6b5b6
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Showing 4 changed files with 116 additions and 184 deletions.
diff --git a/nselib/coap.lua b/nselib/coap.lua
@@ -1,4 +1,3 @@
-local bin = require "bin"
 local comm = require "comm"
 local json = require "json"
 local lpeg = require "lpeg"
@@ -329,22 +328,23 @@ COAP.header.build = function(options)
   code = COAP.header.codes.build(code)
 
   -- Build the fixed portion of the header.
-  local pkt = ""
 
   ver = ver << 6
   mtype = mtype << 4
 
-  pkt = pkt .. bin.pack("C", ver | mtype | tkl)
-  pkt = pkt .. code
-  pkt = pkt .. bin.pack(">S", id)
-  pkt = pkt .. token
+  local pkt = {
+    string.pack("B", ver | mtype | tkl),
+    code,
+    string.pack(">I2", id),
+    token,
+  }
 
   -- Include optional portions of the header.
   if options["options"] then
-    pkt = pkt .. COAP.header.options.build(options.options)
+    pkt[#pkt+1] = COAP.header.options.build(options.options)
   end
 
-  return pkt
+  return table.concat(pkt)
 end
 
 --- Parses a CoAP message header.
@@ -361,24 +361,18 @@ end
 --         string containing the error message on failure.
 COAP.header.parse = function(buf, pos)
   assert(type(buf) == "string")
-  if #buf < 4 then
-    return false, "Cannot parse a string of less than four bytes."
-  end
 
   if not pos or pos == 0 then
     pos = 1
   end
   assert(type(pos) == "number")
   assert(pos <= #buf)
 
-  if pos + 4 - 1 > #buf then
+  if #buf - pos + 1 < 4 then
     return false, "Fixed header extends past end of buffer."
   end
 
-  local pos, ver_type_tkl, code, id = bin.unpack("CA>S", buf, pos)
-  if not pos then
-    return false, "Failed to parse fixed header."
-  end
+  local ver_type_tkl, code, id, pos = string.unpack(">Bc1I2", buf, pos)
 
   -- Parse the fixed header.
   local hdr = {}
@@ -486,7 +480,7 @@ COAP.header.codes.build = function(name)
 
   class = class << 5
 
-  return bin.pack("C", class | detail)
+  return string.pack("B", class | detail)
 end
 
 --- Parses a CoAP request or response code.
@@ -511,7 +505,7 @@ COAP.header.codes.parse = function(buf, pos)
   assert(type(pos) == "number")
   assert(pos <= #buf)
 
-  local pos, id = bin.unpack("C", buf, pos)
+  local id, pos = string.unpack("B", buf, pos)
   if not pos then
     return false, id
   end
@@ -1462,20 +1456,8 @@ COAP.header.options.value.uint.build = function(val)
   if val == 0 then
     return ""
   end
-
-  if val <= 255 then
-    return bin.pack("C", val)
-  end
-
-  if val <= 65535 then
-    return bin.pack(">S", val)
-  end
-
-  if val <= 16777215 then
-    return bin.pack(">I", val):sub(2, 5)
-  end
-
-  return bin.pack(">I", val)
+  -- strip leading null bytes to use smallest space
+  return string.pack(">I16", val):gsub("^\0*","")
 end
 
 --- Parses a CoAP message Uint header option value.
@@ -1490,25 +1472,15 @@ end
 COAP.header.options.value.uint.parse = function(buf)
   assert(type(buf) == "string")
   assert(#buf >= 0)
-  assert(#buf <= 4)
+  assert(#buf <= 16)
 
   if #buf == 0 then
     return 0
   end
 
-  local val, pos
-  if #buf == 1 then
-    pos, val = bin.unpack("C", buf)
-  elseif #buf == 2 then
-    pos, val = bin.unpack(">S", buf)
-  elseif #buf == 3 then
-    pos, val = bin.unpack(">I", string.char(0x00) .. buf)
-  else
-    pos, val = bin.unpack(">I", buf)
-  end
+  local val = string.unpack(">I" .. #buf, buf)
 
   -- There should be no way for this to fail.
-  assert(pos)
   assert(val)
   assert(type(val) == "number")
 
@@ -1567,19 +1539,18 @@ COAP.header.options.delta_length.build = function(delta, length)
     end
 
     if num <= 268 then
-      return 13, bin.pack("C", num - 13)
+      return 13, string.pack("B", num - 13)
     end
 
-    return 14, bin.pack(">S", num - 269)
+    return 14, string.pack(">I2", num - 269)
   end
 
   local d1, d2 = build(delta)
   local l1, l2 = build(length)
 
   d1 = d1 << 4
-  bin.pack("C", d1 | l1)
 
-  return bin.pack("C", d1 | l1) .. d2 .. l2
+  return string.pack("B", d1 | l1) .. d2 .. l2
 end
 
 --- Parse the variable-length option delta and length field.
@@ -1613,7 +1584,7 @@ COAP.header.options.delta_length.parse = function(buf, pos)
   assert(type(pos) == "number")
   assert(pos <= #buf)
 
-  local pos, delta_and_length = bin.unpack("C", buf, pos)
+  local delta_and_length, pos = string.unpack("B", buf, pos)
   if not pos then
     return false, nil, nil, delta_and_length
   end
@@ -1636,20 +1607,20 @@ COAP.header.options.delta_length.parse = function(buf, pos)
 
   if delta == 13 then
     required_bytes = required_bytes + 1
-    dspec = "C"
+    dspec = "B"
   elseif delta == 14 then
     required_bytes = required_bytes + 2
     delta = 269
-    dspec = ">S"
+    dspec = ">I2"
   end
 
   if length == 13 then
     required_bytes = required_bytes + 1
-    lspec = "C"
+    lspec = "B"
   elseif length == 14 then
     required_bytes = required_bytes + 2
     length = 269
-    lspec = ">S"
+    lspec = ">I2"
   end
 
   if pos + required_bytes - 1 > #buf then
@@ -1659,7 +1630,7 @@ COAP.header.options.delta_length.parse = function(buf, pos)
   -- Extract the remaining bytes of each field.
   if dspec then
     local num
-    pos, num = bin.unpack(dspec, buf, pos)
+    num, pos = string.unpack(dspec, buf, pos)
     if not pos then
       return false, nil, nil, num
     end
@@ -1668,7 +1639,7 @@ COAP.header.options.delta_length.parse = function(buf, pos)
 
   if lspec then
     local num
-    pos, num = bin.unpack(lspec, buf, pos)
+    num, pos = string.unpack(lspec, buf, pos)
     if not pos then
       return false, nil, nil, num
     end
@@ -2426,7 +2397,7 @@ local tests = {
     {
       {["name"] = "etag", ["value"] = "ETAGETAG"},
     },
-    bin.pack("CA", 0x48, "ETAGETAG")
+    "\x48ETAGETAG"
   },
   {
     -- Before
@@ -2450,7 +2421,7 @@ local tests = {
       {["name"] = "uri_path", ["value"] = "foo"},
       {["name"] = "max_age", ["value"] = 0},
     },
-    bin.pack("CAC", 0xB3, "foo", 0x30)
+    "\xB3foo\x30"
   },
   {
     -- Before
@@ -2463,7 +2434,7 @@ local tests = {
       {["name"] = "uri_path", ["value"] = ".well-known"},
       {["name"] = "uri_path", ["value"] = "core"},
     },
-    bin.pack("CACA", 0xBB, ".well-known", 0x04, "core")
+    "\xBB.well-known\x04core"
   },
   {
     -- Before
@@ -2482,14 +2453,7 @@ local tests = {
       {["name"] = "uri_path", ["value"] = "core"},
       {["name"] = "max_age", ["value"] = 0},
     },
-    bin.pack(
-      "CACCACAC",
-      0x48, "ETAGETAG",    -- ID:  4, Delta: 4
-      0x10,                -- ID:  5, Delta: 1
-      0x6B, ".well-known", -- ID: 11, Delta: 6
-      0x04, "core",        -- ID: 11, Delta: 0
-      0x30                 -- ID: 14, Delta: 3
-    )
+    "\x48ETAGETAG\x10\x6B.well-known\x04core\x30"
   },
 }
 
@@ -2537,15 +2501,7 @@ local tests = {
         {["name"] = "uri_path", ["value"] = "core"},
       },
     },
-    bin.pack(
-      "CC>SACACA",
-      0x48,
-      0x01,
-      0x1234,
-      "nmapcoap",
-      0xBB, ".well-known",
-      0x04, "core"
-    )
+    "\x48\x01\x12\x34nmapcoap\xBB.well-known\x04core"
   },
 }