controller: prevent duplicate tunnel pairs in rendered configs#3058
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controller: prevent duplicate tunnel pairs in rendered configs#3058
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…onfigs User tunnels are GRE tunnels identified by (UnderlaySrcIP, UnderlayDstIP) pairs. In normal operation, the activator ensures each device gets unique tunnel pairs, but corrupted onchain state or bugs could create duplicates. If duplicate pairs exist when the controller renders device configs, the resulting configuration will contain conflicting GRE tunnel interface definitions, causing device configuration errors or undefined behavior. Add a defensive deduplication layer in GetConfig() that filters the tunnel list before rendering. When duplicates are detected: - Log an error with full context (device pubkey/code, tunnel IDs, user pubkeys, underlay IPs, VRF ID) - Increment controller_duplicate_tunnel_pairs_total Prometheus metric - Keep the first occurrence and remove subsequent duplicates - Continue rendering the rest of the config normally This fail-safe prevents bad configs from reaching devices even if upstream validation fails. The deduplication happens per-device at render time using a shallow device copy, so the cache remains faithful to onchain state while devices receive only valid configurations. Testing: Added 5 unit tests covering duplicate removal, first-occurrence selection, unallocated tunnel handling, empty lists, and end-to-end integration with GetConfig(). All existing tests pass.
nikw9944
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User tunnels are GRE tunnels identified by (UnderlaySrcIP, UnderlayDstIP) pairs. In normal operation, the activator ensures each device gets unique tunnel pairs, but corrupted onchain state or bugs could create duplicates. If duplicate pairs exist when the controller renders device configs, the resulting configuration will contain conflicting GRE tunnel interface definitions, causing device configuration errors or undefined behavior. ## Summary of Changes * Add a defensive deduplication layer in GetConfig() that filters the tunnel list before rendering. When duplicates are detected: * Log an error with full context (device pubkey/code, tunnel IDs, user pubkeys, underlay IPs, VRF ID) * Increment controller_duplicate_tunnel_pairs_total Prometheus metric * Keep the first occurrence and remove subsequent duplicates * Continue rendering the rest of the config normally This fail-safe prevents bad configs from reaching devices even if upstream validation fails. The deduplication happens per-device at render time using a shallow device copy, so the cache remains faithful to onchain state while devices receive only valid configurations. ## Testing Verification * Added 5 unit tests covering duplicate removal, first-occurrence selection, unallocated tunnel handling, empty lists, and end-to-end integration with GetConfig(). * All existing tests pass.
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User tunnels are GRE tunnels identified by (UnderlaySrcIP, UnderlayDstIP) pairs. In normal operation, the activator ensures each device gets unique tunnel pairs, but corrupted onchain state or bugs could create duplicates. If duplicate pairs exist when the controller renders device configs, the resulting configuration will contain conflicting GRE tunnel interface definitions, causing device configuration errors or undefined behavior.
Summary of Changes
This fail-safe prevents bad configs from reaching devices even if upstream validation fails. The deduplication happens per-device at render time using a shallow device copy, so the cache remains faithful to onchain state while devices receive only valid configurations.
Testing Verification