Editing OpenSimulator Internals/Code Map/LLUDP (section)

== Connection Establishment (HandleUseCircuitCode) ==

Triggered when a UseCircuitCode packet arrives from an endpoint with no existing client:

# IsClientAuthorized() -- validates session/agent/circuit code via AgentCircuitManager.AuthenticateSession()
# On success: AddClient() creates the LLUDPClient and LLClientView, starts the client
# If AgentCircuitData is missing (shouldn't happen for a legitimately authorized circuit), the agent is force-closed
# Any packets that arrived and were queued in m_pendingCache while the client was being created are reinjected into PacketReceived()
# SendRegionHandshake() is called if this is not a teleport (teleportFlags <= 0)
# On authorization failure: pending cache entry removed, warning logged, no client created

AddClient() is synchronized across the whole scene (lock (this)) to avoid race conditions -- referenced Mantis #5365 in source comments as the reason.

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