102-drop-opt.txt 1.3 KB

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  1. Filename: 102-drop-opt.txt
  2. Title: Dropping "opt" from the directory format
  3. Version: $Revision$
  4. Last-Modified: $Date$
  5. Author: Nick Mathewson
  6. Created: Jan 2007
  7. Status: Closed
  8. Implemented-In: 0.2.0.x
  9. Overview:
  10. This document proposes a change in the format used to transmit router and
  11. directory information.
  12. This proposal has been accepted, implemented, and merged into dir-spec.txt.
  13. Proposal:
  14. The "opt" keyword in Tor's directory formats was originally intended to
  15. mean, "it is okay to ignore this entry if you don't understand it"; the
  16. default behavior has been "discard a routerdesc if it contains entries you
  17. don't recognize."
  18. But so far, every new flag we have added has been marked 'opt'. It would
  19. probably make sense to change the default behavior to "ignore unrecognized
  20. fields", and add the statement that clients SHOULD ignore fields they don't
  21. recognize. As a meta-principle, we should say that clients and servers
  22. MUST NOT have to understand new fields in order to use directory documents
  23. correctly.
  24. Of course, this will make it impossible to say, "The format has changed a
  25. lot; discard this quietly if you don't understand it." We could do that by
  26. adding a version field.
  27. Status:
  28. * We stopped requiring it as of 0.1.2.5-alpha. We'll stop generating it
  29. once earlier formats are obsolete.