[sameer]

Host.send_control previously serialized UCI control packets into a single frame without fragmentation. Control payloads exceeding the 255-byte UCI payload limit, such as multicast list updates containing multiple extended subsession keys, overflowed the single-byte length field and failed transmission.

Segment serialized control payloads into 255-byte chunks, set the Packet Boundary Flag on intermediate frames, and add test coverage exercising multicast list updates across packet boundaries.

[gemini-code-assist]

Code Review

This pull request implements packet fragmentation for UCI control packets in the send_control method, splitting payloads larger than 255 bytes into multiple fragments with the appropriate Packet Boundary Flag (PBF). It also adds a test case in tests/ranging.py to validate this fragmentation behavior. The review feedback recommends adding defensive checks to ensure the packet is not null and has a minimum length of 4 bytes to prevent potential runtime errors.

[gemini-code-assist]

Add defensive checks to ensure that the input packet is not None and that the serialized packet is at least 4 bytes long (the minimum size of a valid UCI control packet header). This prevents potential AttributeError and IndexError crashes during serialization and fragmentation.

Suggested change

	raw = packet.serialize()
	chunks = [raw[i : i + 255] for i in range(4, len(raw), 255)] or [b""]
	if packet is None:
	raise ValueError("Packet cannot be None")
	raw = packet.serialize()
	if len(raw) < 4:
	raise ValueError(f"Control packet must be at least 4 bytes, got {len(raw)}")
	chunks = [raw[i : i + 255] for i in range(4, len(raw), 255)] or [b""]

[sameer]

The test client methods receive typed PDL packet instances that serialize to valid UCI headers; defensive type checks aren't used elsewhere in Host and would add unreached branches to test code.