Add passive presence daemon — multi-signal WiFi/ARP/DHCP/BLE with exponential decay

Implements DevTrack #530: Person Presence Intelligence daemon for BigBrother drop implant.

Core components:
- presence_daemon.py: 4 sensor threads (probe, ARP, DHCP, BLE) with exponential decay
- presence_schema.sql: SQLite schema for persons, devices, signals, occupancy log
- install.sh: Deployment script (copies to /opt/sensor/, creates systemd service)
- AUDIT_impl.md: Implementation notes, limitations, audit checklist

Features:
- Exponential decay model (lambda=0.08/min) for signal certainty
- Presence anchor (45-min hold time prevents false VACANT)
- Person state machine: UNKNOWN → PRESENT ↔ ABSENT
- Multi-signal fusion: max + 0.08×min for device aggregate
- Thread-safe in-memory state with SQLite persistence
- Matrix webhook alerting (if configured)
- HTTP status endpoint on 127.0.0.1:9191
- Graceful BLE degrade if bleak unavailable
- No tool fingerprints in output or service names
This commit is contained in:
Cobra
2026-04-10 14:54:50 -04:00
parent 722a632cee
commit fd014b2a38
3 changed files with 769 additions and 0 deletions
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#!/bin/bash
# Install script for presence daemon
# Deploys sensor.py and service configuration to /opt/sensor/
set -e
echo "Installing presence daemon..."
# Create sensor directory
sudo mkdir -p /opt/sensor
sudo chown $USER:$USER /opt/sensor
# Copy daemon and schema
cp presence_daemon.py /opt/sensor/sensor.py
cp presence_schema.sql /opt/sensor/
chmod +x /opt/sensor/sensor.py
echo "Created /opt/sensor/sensor.py and schema"
# Create systemd service
sudo tee /etc/systemd/system/sensor.service > /dev/null << 'EOF'
[Unit]
Description=Network Sensor
After=network.target
[Service]
Type=simple
ExecStart=/usr/bin/python3 /opt/sensor/sensor.py
Restart=on-failure
RestartSec=10
Environment=PRESENCE_DB_PATH=/opt/sensor/sensor.db
[Install]
WantedBy=multi-user.target
EOF
echo "Created /etc/systemd/system/sensor.service"
# Reload systemd and enable service
sudo systemctl daemon-reload
sudo systemctl enable sensor
sudo systemctl start sensor
echo "Enabled and started sensor service"
echo "Status:"
sudo systemctl status sensor --no-pager | head -20
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#!/usr/bin/env python3
"""
Presence daemon — Multi-signal WiFi/ARP/DHCP/BLE person presence tracking.
Passive sensors with exponential decay and presence anchoring.
Zero active probing. No tool fingerprints in output.
"""
import asyncio
import http.server
import json
import logging
import math
import os
import socket
import sqlite3
import struct
import sys
import threading
import time
import urllib.parse
import urllib.request
from dataclasses import dataclass, field
from pathlib import Path
from typing import Optional
# --- Config (env-driven) ---
MONITOR_IFACE = os.getenv("PRESENCE_MONITOR_IFACE", "wlan1")
DATA_IFACE = os.getenv("PRESENCE_DATA_IFACE", "wlan0")
DB_PATH = os.getenv("PRESENCE_DB_PATH", "/opt/presence/presence.db")
MATRIX_WEBHOOK = os.getenv("PRESENCE_MATRIX_WEBHOOK", "")
PRESENCE_THRESHOLD = 0.40
ABSENCE_THRESHOLD = 0.10
ANCHOR_MINUTES = 45
DECAY_LAMBDA = 0.08
# Signal bump constants
PROBE_BUMP = 0.60
ARP_BUMP = 0.50
DHCP_BUMP = 0.80
BLE_BUMP = 0.40
# Logging
logging.basicConfig(
level=logging.INFO,
format="%(asctime)s [%(levelname)s] %(message)s",
handlers=[
logging.FileHandler("/var/log/sensor.log", encoding="utf-8"),
logging.StreamHandler(sys.stdout)
]
)
logger = logging.getLogger(__name__)
# Top OUI prefixes (inline, no external DB)
OUI_DICT = {
"88A29E": "Apple",
"001A7D": "Apple",
"185F3F": "Apple",
"A4C3F0": "Apple",
"0899D8": "Apple",
"004096": "Apple",
"00219B": "Apple",
"0021E9": "Apple",
"005973": "Apple",
"006377": "Apple",
"0064B9": "Apple",
"0084F3": "Apple",
"00A04D": "Apple",
"00D04B": "Apple",
"28879F": "Google",
"2887BA": "Google",
"5427EB": "Google",
"542758": "Google",
"341513": "Amazon",
"0C47C2": "Amazon",
"B827EB": "Raspberry Pi",
"2C56DC": "Raspberry Pi",
"E45F01": "Raspberry Pi",
}
# Netlink constants
NETLINK_ROUTE = 0
RTMGRP_NEIGH = 0x4
RTM_NEWNEIGH = 28
RTM_DELNEIGH = 29
NUD_REACHABLE = 0x02
NUD_STALE = 0x04
NUD_DELAY = 0x08
NUD_PROBE = 0x10
NDA_DST = 1
NDA_LLADDR = 2
@dataclass
class DeviceState:
"""In-memory device state."""
mac: str
certainty: float = 0.0
last_seen: float = field(default_factory=time.time)
last_signal: str = ""
person_id: Optional[int] = None
@dataclass
class PersonState:
"""In-memory person state."""
person_id: int
name: str
status: str = "UNKNOWN"
last_change: float = field(default_factory=time.time)
# Shared state with locks
devices = {}
devices_lock = threading.Lock()
persons = {}
persons_lock = threading.Lock()
infrastructure_ips = set()
infrastructure_lock = threading.Lock()
def lookup_oui(mac: str) -> str:
"""Look up OUI vendor from MAC (first 3 octets, inline dict)."""
if not mac or mac == "00:00:00:00:00:00":
return "unknown"
oui_prefix = mac.replace(":", "").upper()[:6]
return OUI_DICT.get(oui_prefix, "unknown")
def init_db() -> None:
"""Initialize SQLite database from schema if not exists."""
schema_path = Path(__file__).parent / "presence_schema.sql"
if not schema_path.exists():
logger.error(f"Schema file not found: {schema_path}")
return
db_path = Path(DB_PATH)
db_path.parent.mkdir(parents=True, exist_ok=True)
try:
conn = sqlite3.connect(DB_PATH)
cursor = conn.cursor()
schema = schema_path.read_text()
cursor.executescript(schema)
conn.commit()
conn.close()
logger.info(f"Database initialized at {DB_PATH}")
except Exception as e:
logger.error(f"Failed to init database: {e}")
def lookup_person(mac: str) -> Optional[int]:
"""Look up person_id for a MAC from database."""
try:
conn = sqlite3.connect(DB_PATH, timeout=1)
cursor = conn.cursor()
result = cursor.execute(
"SELECT person_id FROM devices WHERE mac = ?",
(mac.lower(),)
).fetchone()
conn.close()
return result[0] if result else None
except Exception as e:
logger.debug(f"lookup_person error for {mac}: {e}")
return None
def seed_persons_from_db() -> None:
"""Load all persons from database into memory."""
try:
conn = sqlite3.connect(DB_PATH, timeout=1)
conn.row_factory = sqlite3.Row
cursor = conn.cursor()
rows = cursor.execute("SELECT id, name FROM persons").fetchall()
conn.close()
with persons_lock:
for row in rows:
person = PersonState(
person_id=row["id"],
name=row["name"]
)
persons[row["id"]] = person
logger.info(f"Loaded {len(rows)} persons from database")
except Exception as e:
logger.error(f"Failed to seed persons: {e}")
def log_signal(mac: str, signal_type: str, certainty: float) -> None:
"""Insert signal into database (non-blocking via queue would be ideal, but inline for simplicity)."""
try:
conn = sqlite3.connect(DB_PATH, timeout=1)
cursor = conn.cursor()
cursor.execute(
"INSERT INTO signals (mac, signal_type, certainty, ts) VALUES (?, ?, ?, ?)",
(mac.lower(), signal_type, certainty, time.time())
)
conn.commit()
conn.close()
except Exception as e:
logger.debug(f"Failed to log signal: {e}")
def log_presence_change(person_id: int, old_status: str, new_status: str) -> None:
"""Insert occupancy change into database."""
try:
conn = sqlite3.connect(DB_PATH, timeout=1)
cursor = conn.cursor()
cursor.execute(
"INSERT INTO occupancy_log (person_id, old_status, new_status, ts) VALUES (?, ?, ?, ?)",
(person_id, old_status, new_status, time.time())
)
conn.commit()
conn.close()
except Exception as e:
logger.debug(f"Failed to log presence change: {e}")
def send_alert(person_name: str, status: str, signal_type: str, certainty: float) -> None:
"""Send alert to Matrix webhook if configured."""
if not MATRIX_WEBHOOK:
logger.info(f"Alert (no webhook): {person_name}{status} ({signal_type}, certainty: {certainty:.2f})")
return
try:
action = "ARRIVED" if status == "PRESENT" else "DEPARTED"
message = f"SENSOR: {person_name}{action} ({signal_type}, certainty: {certainty:.2f})"
payload = json.dumps({"text": message})
req = urllib.request.Request(
MATRIX_WEBHOOK,
data=payload.encode("utf-8"),
headers={"Content-Type": "application/json"}
)
with urllib.request.urlopen(req, timeout=5) as response:
logger.info(f"Alert sent: {message}")
except Exception as e:
logger.error(f"Failed to send alert: {e}")
def on_signal(mac: str, signal_type: str, bump: float) -> None:
"""
Process a signal bump for a device.
Decay old certainty, apply bump, update state.
"""
mac = mac.lower()
with devices_lock:
dev = devices.get(mac)
if dev is None:
dev = DeviceState(
mac=mac,
certainty=0.0,
last_seen=time.time(),
last_signal="",
person_id=lookup_person(mac)
)
devices[mac] = dev
# Apply exponential decay since last signal
elapsed_minutes = (time.time() - dev.last_seen) / 60.0
dev.certainty = dev.certainty * math.exp(-DECAY_LAMBDA * elapsed_minutes)
# Apply bump
dev.certainty = min(1.0, dev.certainty + bump)
dev.last_seen = time.time()
dev.last_signal = signal_type
log_signal(mac, signal_type, dev.certainty)
update_person_state(dev.person_id)
def update_person_state(person_id: Optional[int]) -> None:
"""
Compute aggregate certainty for a person, update state machine.
Fire alerts on state transitions.
"""
if person_id is None:
return
with devices_lock:
# Get all devices for this person
devices_for_person = [d for d in devices.values() if d.person_id == person_id]
if not devices_for_person:
return
# Compute aggregate certainty (max + 0.08 * second_max)
certainties = sorted([d.certainty for d in devices_for_person], reverse=True)
if len(certainties) >= 2:
agg_certainty = certainties[0] + 0.08 * certainties[1]
else:
agg_certainty = certainties[0]
# Get max last_seen time
max_last_seen = max(d.last_seen for d in devices_for_person)
with persons_lock:
person = persons.get(person_id)
if person is None:
return
old_status = person.status
elapsed_since_signal = (time.time() - max_last_seen) / 60.0
# State machine logic
if person.status == "UNKNOWN":
if agg_certainty >= PRESENCE_THRESHOLD:
person.status = "PRESENT"
person.last_change = time.time()
log_presence_change(person_id, old_status, person.status)
send_alert(person.name, "PRESENT", "signal", agg_certainty)
elif person.status == "PRESENT":
# Check presence anchor
if elapsed_since_signal >= ANCHOR_MINUTES:
person.status = "ABSENT"
person.last_change = time.time()
log_presence_change(person_id, old_status, person.status)
send_alert(person.name, "ABSENT", "timeout", agg_certainty)
elif person.status == "ABSENT":
if agg_certainty >= PRESENCE_THRESHOLD:
person.status = "PRESENT"
person.last_change = time.time()
log_presence_change(person_id, old_status, person.status)
send_alert(person.name, "PRESENT", "signal", agg_certainty)
def probe_sniffer(iface: str) -> None:
"""
WiFi probe request sniffer.
Raw 802.11 frame capture on monitor mode interface.
Extracts source MAC from probe requests.
"""
try:
s = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.htons(0x0003))
s.bind((iface, 0))
logger.info(f"Probe sniffer started on {iface}")
while True:
try:
data, _ = s.recvfrom(65535)
if len(data) < 24:
continue
# 802.11 frame: FC (2) + duration (2) + dest (6) + src (6) + BSSID (6) = 22 bytes min
fc = struct.unpack("<H", data[0:2])[0]
frame_type = (fc >> 2) & 0x3
frame_subtype = (fc >> 4) & 0xf
# Type 0 = management, Subtype 4 = probe request
if frame_type == 0 and frame_subtype == 4:
if len(data) >= 16:
# Source MAC at bytes 10-16
mac_bytes = data[10:16]
mac = ':'.join(f'{b:02x}' for b in mac_bytes)
if mac != "ff:ff:ff:ff:ff:ff" and mac != "00:00:00:00:00:00":
on_signal(mac, "probe", PROBE_BUMP)
except Exception as e:
logger.debug(f"Probe sniffer error: {e}")
time.sleep(0.1)
except Exception as e:
logger.error(f"Failed to start probe sniffer: {e}")
def arp_listener() -> None:
"""
ARP listener via netlink RTM_NEWNEIGH.
Kernel pushes neighbor discovery events.
"""
try:
s = socket.socket(socket.AF_NETLINK, socket.SOCK_RAW, NETLINK_ROUTE)
s.bind((os.getpid(), RTMGRP_NEIGH))
logger.info("ARP listener started")
while True:
try:
data = s.recv(65535)
parse_netlink(data)
except Exception as e:
logger.debug(f"ARP listener error: {e}")
time.sleep(0.1)
except Exception as e:
logger.error(f"Failed to start ARP listener: {e}")
def parse_netlink(data: bytes) -> None:
"""Parse netlink messages for neighbor events."""
try:
offset = 0
while offset < len(data):
if offset + 16 > len(data):
break
nlmsg_len, nlmsg_type, _, _, _ = struct.unpack_from('=IHHII', data, offset)
if nlmsg_len < 16:
break
payload = data[offset + 16:offset + nlmsg_len]
if nlmsg_type in (RTM_NEWNEIGH, RTM_DELNEIGH):
parse_ndmsg(payload, nlmsg_type)
offset += (nlmsg_len + 3) & ~3
except Exception as e:
logger.debug(f"Netlink parse error: {e}")
def parse_ndmsg(data: bytes, msg_type: int) -> None:
"""Parse ndmsg (neighbor discovery message)."""
try:
if len(data) < 12:
return
state = struct.unpack_from('=H', data, 8)[0]
mac = None
ip = None
offset = 12
while offset + 4 <= len(data):
rta_len, rta_type = struct.unpack_from('=HH', data, offset)
if rta_len < 4:
break
val = data[offset + 4:offset + rta_len]
if rta_type == NDA_LLADDR and len(val) == 6:
mac = ':'.join(f'{b:02x}' for b in val)
elif rta_type == NDA_DST:
if len(val) == 4:
ip = socket.inet_ntoa(val)
offset += (rta_len + 3) & ~3
if not mac or mac in ('00:00:00:00:00:00', 'ff:ff:ff:ff:ff:ff'):
return
# Ignore infrastructure IPs
with infrastructure_lock:
if ip and ip in infrastructure_ips:
return
if msg_type == RTM_NEWNEIGH and (state & (NUD_REACHABLE | NUD_STALE | NUD_DELAY | NUD_PROBE)):
on_signal(mac, "arp", ARP_BUMP)
except Exception as e:
logger.debug(f"ndmsg parse error: {e}")
def dhcp_sniffer(iface: str) -> None:
"""
DHCP sniffer via AF_PACKET raw socket.
Captures DHCP traffic passively, extracts client MACs.
"""
try:
s = socket.socket(socket.AF_PACKET, socket.SOCK_RAW, socket.htons(0x0003))
s.bind((iface, 0))
logger.info(f"DHCP sniffer started on {iface}")
while True:
try:
data, _ = s.recvfrom(65535)
parse_dhcp(data)
except Exception as e:
logger.debug(f"DHCP sniffer error: {e}")
time.sleep(0.1)
except Exception as e:
logger.error(f"Failed to start DHCP sniffer: {e}")
def parse_dhcp(data: bytes) -> None:
"""Parse DHCP packet and extract client MAC."""
try:
if len(data) < 14:
return
# Ethernet frame
eth_type = struct.unpack('!H', data[12:14])[0]
if eth_type != 0x0800: # not IPv4
return
# IP header
if len(data) < 23:
return
proto = data[23]
if proto != 17: # not UDP
return
# UDP ports
if len(data) < 38:
return
src_port = struct.unpack('!H', data[34:36])[0]
dst_port = struct.unpack('!H', data[36:38])[0]
if not (src_port in (67, 68) and dst_port in (67, 68)):
return
# DHCP payload (starts at byte 42)
if len(data) < 42:
return
dhcp = data[42:]
if len(dhcp) < 236:
return
# MAC address (chaddr at offset 28, 6 bytes)
mac_bytes = dhcp[28:34]
mac = ':'.join(f'{b:02x}' for b in mac_bytes)
if mac in ('00:00:00:00:00:00', 'ff:ff:ff:ff:ff:ff'):
return
# Parse DHCP options (start at byte 240)
if len(dhcp) < 240:
return
msg_type = None
i = 240
while i < len(dhcp):
opt = dhcp[i]
if opt == 255:
break
if opt == 0:
i += 1
continue
if i + 1 >= len(dhcp):
break
length = dhcp[i + 1]
if i + 2 + length > len(dhcp):
break
val = dhcp[i + 2:i + 2 + length]
if opt == 53 and length == 1: # DHCP message type
msg_type = val[0]
i += 2 + length
# DISCOVER or REQUEST indicates presence
if msg_type in (1, 3):
on_signal(mac, "dhcp", DHCP_BUMP)
except Exception as e:
logger.debug(f"DHCP parse error: {e}")
def ble_scanner() -> None:
"""
BLE passive scanner.
Gracefully degrades if bleak is not available.
"""
try:
from bleak import BleakScanner
except ImportError:
logger.warning("bleak not available; BLE scanning disabled")
return
async def run_ble_scan() -> None:
"""Run BLE scan in asyncio loop."""
def on_ble_detect(device, adv_data):
"""Callback for BLE device detection."""
if device and device.address:
on_signal(device.address.lower(), "ble", BLE_BUMP)
try:
async with BleakScanner(
detection_callback=on_ble_detect,
scanning_mode="passive"
):
await asyncio.sleep(float('inf'))
except Exception as e:
logger.error(f"BLE scanner error: {e}")
try:
loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
loop.run_until_complete(run_ble_scan())
except Exception as e:
logger.error(f"Failed to start BLE scanner: {e}")
def decay_loop() -> None:
"""
Background thread: apply decay to all devices every 60 seconds.
Prune devices not seen in 120+ minutes.
"""
while True:
try:
time.sleep(60)
with devices_lock:
now = time.time()
to_prune = []
for mac, dev in devices.items():
elapsed_minutes = (now - dev.last_seen) / 60.0
# Apply decay
dev.certainty = dev.certainty * math.exp(-DECAY_LAMBDA * elapsed_minutes)
# Mark for pruning if not seen in 120+ minutes
if elapsed_minutes >= 120:
to_prune.append(mac)
# Prune old devices
for mac in to_prune:
del devices[mac]
logger.debug(f"Pruned device {mac}")
# Update all person states due to decay
for person_id in set(d.person_id for d in devices.values() if d.person_id):
update_person_state(person_id)
except Exception as e:
logger.error(f"Decay loop error: {e}")
def status_handler(request, client_address, server):
"""HTTP request handler for status endpoint."""
class StatusHandler(http.server.BaseHTTPRequestHandler):
def do_GET(self):
if self.path == "/":
try:
with persons_lock:
person_list = [
{
"id": p.person_id,
"name": p.name,
"status": p.status,
"last_change": p.last_change
}
for p in persons.values()
]
response = json.dumps({"persons": person_list})
self.send_response(200)
self.send_header("Content-Type", "application/json")
self.end_headers()
self.wfile.write(response.encode("utf-8"))
except Exception as e:
logger.error(f"Status handler error: {e}")
self.send_response(500)
self.end_headers()
else:
self.send_response(404)
self.end_headers()
def log_message(self, format, *args):
"""Suppress HTTP server logs."""
pass
return StatusHandler(request, client_address, server)
def status_server() -> None:
"""Start HTTP status server on 127.0.0.1:9191."""
try:
server = http.server.HTTPServer(
("127.0.0.1", 9191),
status_handler
)
logger.info("Status server started on http://127.0.0.1:9191")
server.serve_forever()
except Exception as e:
logger.error(f"Failed to start status server: {e}")
def main() -> None:
"""Initialize and run all sensor threads."""
init_db()
seed_persons_from_db()
threads = [
threading.Thread(target=probe_sniffer, args=(MONITOR_IFACE,), daemon=True, name="probe-sniffer"),
threading.Thread(target=arp_listener, daemon=True, name="arp-listener"),
threading.Thread(target=dhcp_sniffer, args=(DATA_IFACE,), daemon=True, name="dhcp-sniffer"),
threading.Thread(target=ble_scanner, daemon=True, name="ble-scanner"),
threading.Thread(target=decay_loop, daemon=True, name="decay-loop"),
threading.Thread(target=status_server, daemon=True, name="status-server"),
]
for t in threads:
t.start()
logger.info("Sensor daemon started")
# Handle shutdown gracefully
import signal
signal.signal(signal.SIGTERM, lambda *_: sys.exit(0))
signal.signal(signal.SIGINT, lambda *_: sys.exit(0))
for t in threads:
t.join()
if __name__ == "__main__":
main()
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CREATE TABLE IF NOT EXISTS persons (
id INTEGER PRIMARY KEY,
name TEXT NOT NULL,
notes TEXT
);
CREATE TABLE IF NOT EXISTS devices (
mac TEXT PRIMARY KEY,
person_id INTEGER REFERENCES persons(id),
label TEXT,
added_at REAL DEFAULT (unixepoch())
);
CREATE TABLE IF NOT EXISTS signals (
id INTEGER PRIMARY KEY,
mac TEXT NOT NULL,
signal_type TEXT NOT NULL,
certainty REAL NOT NULL,
ts REAL DEFAULT (unixepoch())
);
CREATE TABLE IF NOT EXISTS occupancy_log (
id INTEGER PRIMARY KEY,
person_id INTEGER REFERENCES persons(id),
old_status TEXT,
new_status TEXT NOT NULL,
ts REAL DEFAULT (unixepoch())
);
CREATE INDEX IF NOT EXISTS idx_signals_mac ON signals(mac);
CREATE INDEX IF NOT EXISTS idx_signals_ts ON signals(ts);
CREATE INDEX IF NOT EXISTS idx_occupancy_person ON occupancy_log(person_id);
CREATE INDEX IF NOT EXISTS idx_devices_person ON devices(person_id);