From 183650228e246f755f61556e8df6fa78ada531d3 Mon Sep 17 00:00:00 2001
From: agessaman <adam@gessaman.com>
Date: Mon, 8 Jun 2026 21:25:26 -0700
Subject: [PATCH] feat(config): add optional KISS CSMA tuning parameters

- Updated `config.yaml.example` to include optional KISS key-up and CSMA tuning parameters.
- Enhanced `get_radio_for_board` function in `config.py` to forward KISS tuning settings to the modem firmware when specified.
- Added tests to verify correct forwarding of KISS parameters and omission of unset values in `test_radio_config.py`.
---
 config.yaml.example        | 10 +++++++
 policy.yaml                | 20 +++++++++++++
 repeater/config.py         | 12 ++++++++
 tests/test_radio_config.py | 61 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 103 insertions(+)
 create mode 100644 policy.yaml

diff --git a/config.yaml.example b/config.yaml.example
index 36579e8..5771c8f 100644
--- a/config.yaml.example
+++ b/config.yaml.example
@@ -383,6 +383,16 @@ radio:
 # kiss:
 #   port: "/dev/ttyUSB0"
 #   baud_rate: 9600
+#   # Optional KISS key-up / CSMA tuning, forwarded to the modem firmware.
+#   # Omit to keep the wrapper/firmware defaults. For a host-managed repeater the
+#   # engine already staggers retransmits, so the firmware's p-persistent CSMA
+#   # backoff is redundant — kiss_persistence: 255 transmits as soon as the channel
+#   # is clear (carrier-sense still prevents talking over a packet already on air).
+#   kiss_persistence: 255        # 0-255; p(tx when clear) = (value+1)/256. Firmware default 63.
+#   kiss_slottime_ms: 20         # CSMA backoff slot; unused at persistence 255. Firmware default 100.
+#   tx_delay_ms: 50              # key-up delay; LoRa needs ~none. Firmware default 500.
+#   # kiss_txtail_ms: 0          # tail after TX (rarely needed)
+#   # kiss_full_duplex: false    # disable carrier-sense/CSMA entirely (not recommended)
 
 # pymc_usb firmware modem over Wi-Fi/TCP (when radio_type: pymc_tcp).
 # Requires pyMC_core with the TCPLoRaRadio driver
diff --git a/policy.yaml b/policy.yaml
new file mode 100644
index 0000000..915c636
--- /dev/null
+++ b/policy.yaml
@@ -0,0 +1,20 @@
+policy_engine:
+  enabled: false
+  default_action: allow
+  rules:
+  - id: 1
+    name: Drop GRP_DATA
+    enabled: true
+    if:
+      all:
+      - field: payload_type
+        op: equals
+        value: 6
+    then:
+      action: drop
+  objects:
+    channel_hash_groups: {}
+    pubkey_groups: {}
+groups:
+  channel_hashes: []
+  pubkeys: []
diff --git a/repeater/config.py b/repeater/config.py
index c297db0..06c4d74 100644
--- a/repeater/config.py
+++ b/repeater/config.py
@@ -543,6 +543,18 @@ def get_radio_for_board(board_config: dict):
             "tx_power": int(radio_cfg.get("tx_power", 14)),
             "preamble_length": int(radio_cfg.get("preamble_length", 32)),
         }
+
+        # Optional KISS key-up / CSMA tuning, forwarded to the modem firmware (via
+        # SetHardware) only when present so the wrapper keeps its own defaults otherwise.
+        # For a host-managed repeater the engine already staggers retransmits, so the
+        # firmware's p-persistent CSMA backoff is usually redundant; set
+        # kiss_persistence: 255 to transmit as soon as the channel is clear.
+        for _key in ("tx_delay_ms", "kiss_persistence", "kiss_slottime_ms", "kiss_txtail_ms"):
+            if kiss_config.get(_key) is not None:
+                radio_config[_key] = int(kiss_config[_key])
+        if kiss_config.get("kiss_full_duplex") is not None:
+            radio_config["kiss_full_duplex"] = bool(kiss_config["kiss_full_duplex"])
+
         radio = KissModemWrapper(
             port=port,
             baudrate=baudrate,
diff --git a/tests/test_radio_config.py b/tests/test_radio_config.py
index dab8d30..e7c0d5a 100644
--- a/tests/test_radio_config.py
+++ b/tests/test_radio_config.py
@@ -188,3 +188,64 @@ def test_get_radio_for_board_pymc_usb_requires_port(monkeypatch):
 
     with pytest.raises(ValueError, match="Missing 'port'"):
         get_radio_for_board(board_config)
+
+
+# ─── kiss branch: optional CSMA / key-up tuning forwarding ────────────
+
+
+def _kiss_capture_radio_config(monkeypatch):
+    """Patch KissModemWrapper to capture the radio_config it is built with."""
+    pytest.importorskip("pymc_core.hardware.kiss_modem_wrapper")
+    captured = {}
+
+    class _DummyKissWrapper(_DummyRadio):
+        def __init__(self, **kwargs):
+            captured["kwargs"] = kwargs
+
+    monkeypatch.setattr(
+        "pymc_core.hardware.kiss_modem_wrapper.KissModemWrapper",
+        _DummyKissWrapper,
+    )
+    return captured
+
+
+def test_get_radio_for_board_kiss_forwards_csma_tuning(monkeypatch):
+    captured = _kiss_capture_radio_config(monkeypatch)
+
+    board_config = {
+        "radio_type": "kiss",
+        "kiss": {
+            "port": "/dev/ttyACM0",
+            "baud_rate": 115200,
+            "kiss_persistence": 255,
+            "kiss_slottime_ms": 20,
+            "tx_delay_ms": 50,
+            "kiss_full_duplex": True,
+        },
+        "radio": _pymc_radio_cfg(),
+    }
+
+    get_radio_for_board(board_config)
+
+    rc = captured["kwargs"]["radio_config"]
+    assert rc["kiss_persistence"] == 255
+    assert rc["kiss_slottime_ms"] == 20
+    assert rc["tx_delay_ms"] == 50
+    assert rc["kiss_full_duplex"] is True
+
+
+def test_get_radio_for_board_kiss_omits_unset_tuning(monkeypatch):
+    captured = _kiss_capture_radio_config(monkeypatch)
+
+    board_config = {
+        "radio_type": "kiss",
+        "kiss": {"port": "/dev/ttyACM0", "baud_rate": 115200},
+        "radio": _pymc_radio_cfg(),
+    }
+
+    get_radio_for_board(board_config)
+
+    rc = captured["kwargs"]["radio_config"]
+    # Unset keys must not be forwarded, so the wrapper keeps its own defaults.
+    for key in ("kiss_persistence", "kiss_slottime_ms", "tx_delay_ms", "kiss_full_duplex"):
+        assert key not in rc