feat(k1): stabilize LAB bridge and isolate onboard device integration
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DCCONSTRUCTIONS
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"""Paired signalling, private ICE candidates and bounded live data channels."""
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import asyncio
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import ipaddress
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import queue
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import time
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from contextlib import suppress
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from uuid import uuid4
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import aioice.ice
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from aiortc import RTCConfiguration, RTCPeerConnection, RTCSessionDescription
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PRIVATE_NETWORKS = tuple(
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ipaddress.ip_network(v)
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for v in ("127.0.0.0/8", "10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16", "100.64.0.0/10")
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)
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def private(address):
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try:
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value = ipaddress.ip_address(address)
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return value.version == 4 and any(value in network for network in PRIVATE_NETWORKS)
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except ValueError:
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return False
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def admit_sdp(sdp):
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if not isinstance(sdp, str) or not 1 <= len(sdp) <= 32768:
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raise ValueError("Invalid media invitation")
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media = [line for line in sdp.splitlines() if line.startswith("m=")]
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if not sdp.startswith("v=0") or len(media) != 1 or not media[0].startswith("m=application "):
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raise ValueError("A single data-channel media section is required")
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for line in sdp.splitlines():
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if line.startswith("a=candidate:"):
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parts = line.split()
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if (
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len(parts) < 8
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or parts[7] != "host"
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or not (private(parts[4]) or parts[4].endswith(".local"))
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):
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raise ValueError("Only private host ICE candidates are admitted")
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class NodeMediaPeers:
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def __init__(self, hub, camera):
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self.hub, self.camera, self.items = hub, camera, {}
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# Process-local adapter in this dedicated worker; no public/STUN/TURN ICE.
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original = aioice.ice.get_host_addresses
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aioice.ice.get_host_addresses = lambda use_ipv4, use_ipv6: [
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value for value in original(use_ipv4=True, use_ipv6=False) if private(value)
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]
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async def offer(self, parameters):
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admit_sdp(parameters.get("sdp"))
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if len(self.items) >= 2:
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raise ValueError("Close another live viewer")
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pc = RTCPeerConnection(RTCConfiguration(iceServers=[]))
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identifier = "peer_" + uuid4().hex
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entry = {"pc": pc, "seen": time.monotonic(), "tasks": [], "labels": set()}
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self.items[identifier] = entry
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@pc.on("datachannel")
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def datachannel(channel):
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if channel.label not in {"rrd", "camera"} or channel.label in entry["labels"]:
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channel.close()
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return
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entry["labels"].add(channel.label)
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@channel.on("message")
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def message(value):
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if value == "keepalive":
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entry["seen"] = time.monotonic()
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entry["tasks"].append(asyncio.create_task(self.deliver(identifier, channel)))
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@pc.on("connectionstatechange")
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async def changed():
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if pc.connectionState in {"closed", "failed"}:
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await self.close(identifier)
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try:
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await pc.setRemoteDescription(
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RTCSessionDescription(sdp=parameters["sdp"], type="offer")
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)
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await pc.setLocalDescription(await pc.createAnswer())
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async def expiry():
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await asyncio.sleep(25)
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if pc.connectionState != "connected":
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await self.close(identifier)
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entry["tasks"].append(asyncio.create_task(expiry()))
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snapshot = self.camera.snapshot()
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return {
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"peer_id": identifier,
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"sdp": pc.localDescription.sdp,
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"type": "answer",
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"camera_mime": (snapshot.get("delivery") or {}).get("media_type"),
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"profile": "live-acquisition",
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"transport": "webrtc-rrd-fmp4",
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}
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except BaseException:
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await self.close(identifier)
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raise
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async def send(self, channel, payload):
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if len(payload) > 8 * 1024 * 1024:
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raise RuntimeError("Preview fragment exceeds bound")
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for offset in range(0, len(payload), 16384):
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deadline = time.monotonic() + 2
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while channel.readyState != "open" or channel.bufferedAmount > 1024 * 1024:
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if channel.readyState in {"closed", "closing"} or time.monotonic() > deadline:
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raise RuntimeError("Preview consumer unavailable")
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await asyncio.sleep(0.01)
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channel.send(payload[offset : offset + 16384])
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await asyncio.sleep(0)
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async def deliver(self, identifier, channel):
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subscriber = lease = None
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try:
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entry = self.items[identifier]
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if channel.label == "rrd":
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subscriber = await asyncio.to_thread(self.hub.subscribe)
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else:
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generation = self.camera.snapshot().get("generation")
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if generation is None:
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channel.close()
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return
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lease = await asyncio.to_thread(self.camera.open_delivery, generation)
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while identifier in self.items and time.monotonic() - entry["seen"] < 30:
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if subscriber:
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payload = await asyncio.to_thread(subscriber.read)
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else:
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try:
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segment = await asyncio.to_thread(lease.segments.get, 0.5)
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except queue.Empty:
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continue
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if segment is None:
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break
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kind, payload = segment
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if kind == "media":
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self.camera.mark_streaming(lease)
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if payload is None:
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break
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if payload:
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await self.send(channel, payload)
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except (Exception, asyncio.CancelledError):
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pass
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finally:
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if subscriber:
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subscriber.close()
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if lease:
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self.camera.release_delivery(lease, client_closed=True)
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if channel.label == "camera":
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channel.close()
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else:
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await self.close(identifier)
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async def close(self, identifier):
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entry = self.items.pop(identifier, None)
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if entry:
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for task in entry["tasks"]:
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if task is not asyncio.current_task():
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task.cancel()
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with suppress(Exception):
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await entry["pc"].close()
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async def close_all(self):
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for identifier in list(self.items):
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await self.close(identifier)
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