From 14b1906563a0f9104c5418a6cab871130aff3a05 Mon Sep 17 00:00:00 2001
From: Adeeb Shihadeh <adeebshihadeh@gmail.com>
Date: Sun, 29 Mar 2026 14:47:16 -0700
Subject: [PATCH] Parse health packet layout from health.h (#2378)

* Parse health packet layout from health.h

* Fail closed on unexpected health.h layouts

* cleanup

* define once
---
 python/__init__.py | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/python/__init__.py b/python/__init__.py
index 309c0b85e7..4c954b2395 100644
--- a/python/__init__.py
+++ b/python/__init__.py
@@ -1,5 +1,6 @@
 # python library to interface with panda
 import os
+import re
 import sys
 import time
 import usb1
@@ -42,6 +43,15 @@ def calculate_checksum(data):
     res ^= b
   return res
 
+def _parse_c_struct(path, name):
+  type_to_format = {"uint8_t": "B", "uint16_t": "H", "uint32_t": "I", "float": "f"}
+  with open(path) as f:
+    lines = [l.strip() for l in f.read().split(f"struct __attribute__((packed)) {name} {{", 1)[1].split("};", 1)[0].splitlines() if l.strip()]
+  fields = [re.fullmatch(rf"({'|'.join(type_to_format)})\s+\w+;", l) for l in lines]
+  if not all(fields):
+    raise ValueError(f"unsupported {name} layout in {path}")
+  return struct.Struct("<" + "".join(type_to_format[m[1]] for m in fields))
+
 def pack_can_buffer(arr, chunk=False, fd=False):
   snds = [bytearray(), ]
   for address, dat, bus in arr:
@@ -128,7 +138,7 @@ class Panda:
 
   CAN_PACKET_VERSION = compute_version_hash(os.path.join(opendbc.INCLUDE_PATH, "opendbc/safety/can.h"))
   HEALTH_PACKET_VERSION = compute_version_hash(os.path.join(BASEDIR, "board/health.h"))
-  HEALTH_STRUCT = struct.Struct("<IIIIIIIIBBBBBHBBBHfBBHHHBH")
+  HEALTH_STRUCT = _parse_c_struct(os.path.join(BASEDIR, "board/health.h"), "health_t")
   CAN_HEALTH_STRUCT = struct.Struct("<BIBBBBBBBBIIIIIIIHHBBBIIII")
 
   H7_DEVICES = [HW_TYPE_RED_PANDA, HW_TYPE_TRES, HW_TYPE_CUATRO, HW_TYPE_BODY]