From 20d2dd4e331fbbaf6aea12c8a51d733c1a1c5355 Mon Sep 17 00:00:00 2001
From: s-ol <s+removethis@s-ol.nu>
Date: Sun, 18 Feb 2024 20:42:30 +0100
Subject: dissectors/t937: dissect TEMP_STATUS messages

---
 dissectors/t937.lua | 50 ++++++++++++++++++++++++++++++--------------------
 1 file changed, 30 insertions(+), 20 deletions(-)

diff --git a/dissectors/t937.lua b/dissectors/t937.lua
index 9d37ba6..cec6e9a 100755
--- a/dissectors/t937.lua
+++ b/dissectors/t937.lua
@@ -18,7 +18,11 @@ proto.fields.fun = ProtoField.uint8("t937.function", "Function", base.HEX, FUN_T
 proto.fields.len = ProtoField.uint8("t937.length", "Data Length", base.HEX)
 proto.fields.checksum = ProtoField.uint16("t937.checksum", "Message Checksum", base.HEX)
 
-proto.fields.data = ProtoField.bytes("t937.data", "Data")
+proto.fields.temp1 = ProtoField.uint16("t937.temp1", "Chamber Temp 1", base.UNIT_STRING, {"°C"})
+proto.fields.temp2 = ProtoField.uint16("t937.temp2", "Chamber Temp 2", base.UNIT_STRING, {"°C"})
+proto.fields.temp3 = ProtoField.uint16("t937.temp3", "Control Board Temp", base.UNIT_STRING, {"°C"})
+
+proto.fields.data = ProtoField.bytes("t937.data", "Raw Data")
 
 local function try_dissect(bytes, pinfo, tree)
   -- minimum len is header + checksum
@@ -28,34 +32,40 @@ local function try_dissect(bytes, pinfo, tree)
   if bytes:len() < 4 + raw_len + 2 then return end
 
   local buffer = bytes:subset(0, 4+raw_len+2):tvb("T-937 Frame")
-  local address = buffer(0, 2)
-  local fun = buffer(2, 1)
-  local len = buffer(3, 1)
+  local sub = tree:add(proto, buffer())
+
+  local i = 0
+  sub:add_packet_field(proto.fields.addr, buffer(0, 2), ENC_BIG_ENDIAN)
+  local funf, fun, i = sub:add_packet_field(proto.fields.fun, buffer(2, 1), ENC_BIG_ENDIAN)
+  sub:add_packet_field(proto.fields.len, buffer(3, 1), ENC_BIG_ENDIAN)
   local data = buffer(4, raw_len)
-  local checksum = buffer(4+raw_len, 2)
+  sub:add_packet_field(proto.fields.data, data, ENC_BIG_ENDIAN)
+  local csf, cs = sub:add_packet_field(proto.fields.checksum, buffer(4+raw_len), ENC_BIG_ENDIAN)
 
   local sum = 0
   for i=0,4+raw_len-1 do
     sum = sum + buffer(i, 1):uint()
   end
 
-  pinfo.cols.info:set("T937 " .. (FUN_TABLE[fun:uint()] or ""))
-  pinfo.cols.dst:clear_fence()
-  pinfo.cols.dst:set(address:bytes():tohex())
-
-  local sub = tree:add(proto, buffer())
-  sub:add(proto.fields.addr, address)
-  sub:add(proto.fields.fun, fun)
-  sub:add(proto.fields.len, len)
-  sub:add(proto.fields.data, data)
-
-  local cs = sub:add(proto.fields.checksum, checksum)
-  if sum ~= checksum:uint() then
-    cs:add_proto_expert_info(proto.experts.checksum, string.format(
-      "expected 0x%04x, got 0x%04x", checksum:uint(), sum
+  if sum ~= cs then
+    csf:add_proto_expert_info(proto.experts.checksum, string.format(
+      "expected 0x%04x, got 0x%04x", cs, sum
     ))
   end
 
+  local fun_name = FUN_TABLE[fun]
+  pinfo.cols.info:set("T937 " .. (fun_name or ""))
+
+  if fun_name then
+    sub = sub:add(data, fun_name)
+  end
+
+  if fun_name == "TEMP_STATUS" then
+    sub:add(proto.fields.temp1, data(0,2))
+    sub:add(proto.fields.temp2, data(2,2))
+    sub:add(proto.fields.temp3, data(4,2))
+  end
+
   return buffer:len()
 end
 
@@ -106,9 +116,9 @@ function proto.dissector(_buf, pinfo, tree)
   while rest:len() > 0 do
     local ok, len = pcall(try_dissect, rest, pinfo, tree)
     if not ok then
-      print("GOT ERR", len, pinfo.number)
       state.error[pinfo.p2p_dir] = len
       state.last_number = pinfo.number
+      print(len)
       error(len)
     elseif not len then
       break
-- 
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