Add SNMP trap C extension using net-snmp

Replace pysnmp with a native C extension for sending SNMP trap
notifications. Uses net-snmp's libnetsnmp for session management,
PDU construction, and SNMPv3 USM authentication.

Exposes send_alert(), send_alert_cancellation(), and get_engine_id()
to Python. Supports SNMPv2c (community), SNMPv3 authNoPriv (MD5/SHA),
and SNMPv3 authPriv (DES/AES). OIDs derived from TRUENAS-MIB
notification section.

Author: ixhamza

.gitignore

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+.idea/
+__pycache__/
+*.egg-info/
+*.so

README.md

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+# truenas_pysnmp
+
+Python C extension for SNMP functionality using net-snmp's libnetsnmp.
+
+Currently provides SNMP trap sending (`send_alert`, `send_alert_cancellation`, `get_engine_id`). Supports SNMPv2c and SNMPv3 (USM auth/priv). Notification OIDs (`alert`, `alertCancellation`, `alertId`, `alertLevel`, `alertMessage`) are derived from the notification section of [TRUENAS-MIB](https://github.com/truenas/middleware/blob/master/src/freenas/usr/local/share/snmp/mibs/TRUENAS-MIB.txt) and compiled as constants, so no runtime MIB parsing is required.
+
+## Building
+
+```bash
+sudo apt install libsnmp-dev python3-dev
+pip install -e .
+```

debian/changelog

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+truenas-pysnmp (0.1.0-1) unstable; urgency=medium
+
+  * Initial release.
+
+ -- Ameer Hamza <ahamza@truenas.com>  Fri, 27 Mar 2026 17:00:00 +0000

debian/control

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+Source: truenas-pysnmp
+Section: contrib/python
+Priority: optional
+Maintainer: TrueNAS Engineering <dev@truenas.com>
+Build-Depends: debhelper-compat (= 12),
+               dh-python,
+               pybuild-plugin-pyproject,
+               python3-all-dev,
+               python3-setuptools,
+               libsnmp-dev
+Standards-Version: 4.4.1
+Homepage: https://github.com/truenas/truenas_pysnmp
+
+Package: python3-truenas-pysnmp
+Architecture: any
+Depends: ${shlibs:Depends}, ${misc:Depends}, ${python3:Depends}
+Description: TrueNAS SNMP C extension using net-snmp
+ This package provides a Python C extension for sending SNMP trap
+ notifications using net-snmp's libnetsnmp. Supports SNMPv2c and SNMPv3.

debian/rules

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+#!/usr/bin/make -f
+
+#export DH_VERBOSE = 1
+export DEB_BUILD_MAINT_OPTIONS = hardening=+all
+export PYBUILD_NAME=truenas-pysnmp
+export PYBUILD_SYSTEM=pyproject
+
+%:
+	dh $@ --with python3 --buildsystem=pybuild
+
+override_dh_auto_configure:
+	dh_auto_configure
+
+override_dh_install:
+	dh_install

pyproject.toml

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+[build-system]
+requires = ["setuptools>=64", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "truenas_pysnmp"
+version = "0.1.0"
+description = "TrueNAS SNMP C extension using net-snmp"
+readme = "README.md"
+requires-python = ">=3.11"
+authors = [
+    {name = "TrueNAS Engineering", email = "dev@truenas.com"},
+]
+license = {text = "LGPL-3.0-or-later"}
+classifiers = [
+    "Development Status :: 3 - Alpha",
+    "Intended Audience :: Developers",
+    "Programming Language :: Python :: 3",
+    "Programming Language :: C",
+    "Operating System :: POSIX :: Linux",
+    "Topic :: System :: Networking :: Monitoring",
+]

setup.py

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+from setuptools import setup, Extension
+
+truenas_pysnmp_ext = Extension(
+    'truenas_pysnmp._native',
+    sources=['src/cext/truenas_pysnmp.c'],
+    include_dirs=['src/cext'],
+    libraries=['netsnmp'],
+)
+
+setup(
+    ext_modules=[truenas_pysnmp_ext],
+    packages=['truenas_pysnmp'],
+    package_dir={
+        'truenas_pysnmp': 'stubs',
+    },
+    package_data={
+        'truenas_pysnmp': ['*.pyi', 'py.typed'],
+    },
+)