Paul Lorenz 538623ceb6 Add specific circuit failure error codes. Fixes #3717, fixes #3543, fixes #3364, fixes #2888, fixes #2859, fixes #1580 ...

- adds ErrorType constants for rejected-by-application, DNS resolution failed,
  port not allowed, invalid link destination, and resources not available
- adds corresponding CircuitFailureCause strings reported in circuit events
- extracts classifyDialError() in route handler to map dial errors to specific
  error codes using typed errors, syscall constants, and string matching
- detects DNS errors via *net.DNSError and string fallback for ER/T hosted
  services where errors are serialized through the SDK message protocol
- detects resource exhaustion via EMFILE, ENFILE, ENOBUFS syscall errors
- introduces InvalidLinkDestinationError typed error in forwarder package
- adds unit tests covering all 16 classification cases
- adds integration tests for rejected-by-application (SDK host),
  DNS resolution failed, connection refused, and port not allowed
  (ER/T host mode) with circuit event verification
- adds CreateEnrollAndStartTunnelerEdgeRouterWithCfgTweaks to test context

2026-04-14 15:52:49 -04:00

..

messages.go

Add specific circuit failure error codes. Fixes #3717, fixes #3543, fixes #3364, fixes #2888, fixes #2859, fixes #1580

2026-04-14 15:52:49 -04:00