tor/doc/TODO.021

$Id: TODO 16258 2008-07-30 13:04:38Z nickm $
Legend:
SPEC!!  - Not specified
SPEC    - Spec not finalized
N       - nick claims
R       - arma claims
P       - phobos claims
S       - Steven claims
E       - Matt claims
M       - Mike claims
J       - Jeff claims
I       - ioerror claims
W       - weasel claims
K       - Karsten claims
        - Not done
        * Top priority
        . Partially done
        o Done
        d Deferrable
        D Deferred
        X Abandoned

=======================================================================

Things Roger would be excited to see:

Nick
  * Look at Roger's proposal 141 discussions on or-dev, and help us
    decide how to proceed.
  - Tors start believing the contents of NETINFO cells.
  - respond to Steven's red-team TLS testing (a.k.a, look at a packet
    dump and compare)

Matt
  - Fit Vidalia in 640x480 again.
  - Vidalia should avoid stomping on your custom exit policy lines
    just because you click on 'save' for a totally different config thing.
  - How much space do we save in TBB by stripping symbols from Vidalia
    first? Good idea or crazy idea?

ioerror
  * weather.torproject.org should go live.
  - Keep advocating new Tor servers and working with orgs like Mozilla
    to let them like Tor.
  - Find out what happened to the buildbot and get it back up:
    http://tor-buildbot.freehaven.net:8010/
  - Learn about locking memory pages that have sensitive content. Get
    that started in Tor.
  - Translation portal
    - Vidalia html help files
    - should we i18nize polipo's error messages too?
    - how to get our diagrams translated, and how to get our screenshots
      from the right language?
    - Some of our translated wml files are very old -- so old that they
      are harmful to leave in place. We need some sort of way to notice
      this and disable them.

Steven
  - Move proposal 131 or equivalent forward.
  - Keep bugging us about exploits on the .exit notation.
  - Mike's question #3 on https://www.torproject.org/volunteer#Research
  - Worthwhile shipping TBB with some local html help files that come
    as bookmarks?

Andrew
  - Which bundles include Torbutton? Change the docs/tor-doc-foo pages
    so they admit that Torbutton is in them too. Change the download
    page too.
  - The OS X bundle screenshots are from forever ago -- they don't
    include Torbutton, they still say it's tor.eff.org, etc.
  - Should we still be telling you how to use Safari on OS X for Tor,
    given all the holes that Torbutton-dev solves on Firefox?

Weasel
  - Figure out how to make Vidalia and Tor play nicely on Debian, make
    the necessary modifications, and make some Vidalia debs that pass
    muster.
  - Fix bug 393.
  - Get oftc to switch to Tor dns bulk exitlist. Or tell us why it's
    not suitable yet.
  - Move proposal 134 forward.
  - putting port predictions in state file
  - if tor hasn't been used in a while it stops fetching consensus
    documents.  Retain that state over restarts.

Roger
  - Finish tor-doc-bridge.wml
  . Fix FAQ entry on setting up private Tor network
  - Did we actually apply Steven's dkimproxy patch?
  - Brainstorm about safe but effective ways for vidalia to
    auto-update its user's bridges via Tor in the background.
  - it doesn't count as successfully opening a circuit if it's not
    an exit circuit.

Mike:
  - Roger wants to get an email every time there's a blog change,
    e.g. a comment. That way spam doesn't go undetected for weeks.
    - Or, maybe just disable linking from blog comments entirely?

=======================================================================

Bugs/issues for Tor 0.2.0.x:
  . we should have an off-by-default way for relays to dump geoip data to
    a file in their data directory, for measurement purposes.
    o Basic implementation
N   - Include probability-of-selection
R d let bridges set relaybandwidthrate as low as 5kb
R - bridge communities
    . spec
    . deploy
      - man page entries for Alternate*Authority config options

Documentation for Tor 0.2.0.x:
  - Proposals:
    . 111: Prioritize local traffic over relayed.
R     - Merge into tor-spec.txt.
    - 113: mark as closed close.
  o document the "3/4 and 7/8" business in the clients fetching consensus
    documents timeline.
R   - then document the bridge user download timeline.
  - HOWTO for DNSPort. See tup's wiki page.
  . Document transport and natdport in a good HOWTO.
  - Quietly document NT Service options: revise (or create) FAQ entry

=======================================================================

For 0.2.1.x-alpha:
R d bug: if we launch using bridges, and then stop using bridges, we
    still have our bridges in our entryguards section, and may use them.
R d add an event to report geoip summaries to vidalia for bridge relays,
    so vidalia can say "recent activity (1-8 users) from sa".
R - investigate: it looks like if the bridge authority is unreachable,
    we're not falling back on querying bridges directly?
R - if "no running bridges known", an application request should make
    us retry all our bridges.
R d Setting DirPort when acting as bridge will give false Warnings

For 0.2.1.x:
  - Proposals to do:
    o 110: avoid infinite-length circuits
    - 117: IPv6 Exits
      - Internal code support for ipv6:
        o Clone ipv6 functions (inet_ntop, inet_pton) where they don't exist.
        o Many address variables need to become tor_addr_t
          o addr in connection_t
          o n_addr in extend_info_t
        - Teach resolving code how to handle ipv6.
        . Teach exit policies about ipv6 (consider ipv4/ipv6 interaction!)
        o Use IPv6 in connect/connected/failed-exitpolicy cells
        o accept ipv6 from socks
        o Generate END_REASON_EXITPOLICY cells right
          . ... and parse them right
        . Generate new BEGIN cell types and parse them right
        - Detect availability of ipv6
        - Advertise availability of ipv6.
        - Geoip support, if only to add a zone called "ipv6"

    - 118: Listen on and advertise multiple ports:
      - Tor should be able to have a pool of outgoing IP addresses that it is
        able to rotate through. (maybe.  Possible overlap with proposal 118.)
      - config option to publish what ports you listen on, beyond
        ORPort/DirPort.  It should support ranges and bit prefixes (?) too.
      - Need to figure out the right format for routerinfo_t on this.
K   . 121: Hidden service authentication:
           missing: delayed descriptor publication for 'stealth' mode.
R   d 128: families of private bridges
    - 134: handle authority fragmentation.
    o 135: simplify configuration of private tor networks.
    - 140: Provide diffs betweeen consensuses
K   - 143: Improvements of Distributed Hidden Service Descriptor Storage:
           only easy parts for 0.2.1.x, defer complex ones to 0.2.2.x.
    - 147: Eliminate the need for v2 directories in generating v3 directories
R     - authorities should initiate a reachability test upon first
        glimpsing a new descriptor.
    - 148: Stream end reasons from the client side should be uniform.
K   - 155: Four Improvements of Hidden Service Performance

  - Maybe:
    - 145: Separate "suitable from a guard" from "suitable as a new guard"
    - 146: Adding new flag to reflect long-term stability
    - 149: Using data from NETINFO cells
      - Don't extend a circuit over a noncanonical connection with
        mismatched address.
      - Learn our outgoing IP address from netinfo cells?
      - Learn skew from netinfo cells?

  - Proposals to write:
    - Fix voting to handle bug 608 case when multiple servers get
      Named.
R   d Do we want to maintain our own set of entryguards that we use as
      next hop after the bridge?
    d Possibly: revise link protocol to allow big circuit IDs,
      variable-length cells, proposal-110 stuff, and versioned CREATES?
N   . Draft proposal for GeoIP aggregation (see external constraints *)
    . Figure out how to make good use of the fallback consensus file. Right
      now many of the addresses in the fallback consensus will be stale,
      so it will take dozens of minutes to bootstrap from it. This is a
      bad first Tor experience. But if we check the fallback consensus
      file *after* we fail to connect to any authorities, then it may
      still be valuable as a blocking-resistance step.
      o Write the proposal.
      - Patch our tor.spec rpm package so it knows where to put the fallback
        consensus file.
    d Something for bug 469, to limit connections per IP.
    . Put bandwidth weights in the networkstatus? So clients get weight
      their choices even before they have the descriptors; and so
      authorities can put in more accurate numbers in the future.
    d Fetch an updated geoip file from the directory authorities.

  - Tiny designs to write:
    . Better estimate of clock skew; has anonymity implications.  Clients
      should estimate their skew as median of skew from servers over last
      N seconds, but for servers this is not so easy, since a server does
      not choose who it connects to.
    - Do TLS connection rotation more often than "once a week" in the
      extra-stable case.
      (One reason not to do it more often is because the old TLS conn
       probably has a circuit on it, and we don't really want to build up
       dozens of TCP connections to all the other extra-stable relays.)
    - If a relay publishes a new descriptor with a significantly lower
      uptime or with a new IP address, then we should consider its current
      "running" interval to have ended even if it hadn't yet failed its
      third reachability test. the interval ended when the new descriptor
      appeared, and a new interval began then too.

  - Use less RAM *
    - Optimize cell pool allocation.
    d Support (or just always use) jemalloc (if it helps)
    - mmap more files.
    - Look into pulling serverdescs off buffers as they arrive.
  - Use less bandwidth
    - Use if-modified-since to download consensuses
  - Handle multi-core cpus better
    - Split circuit AES across cores?
    - Split TLS across cores?  This will be harder.
  - Testing
    - Better unit test coverage
    - Refactor unit tests into multiple files
    - Verify that write limits to linked connections work.
  - Use more mid-level and high-level libevent APIs
    - For dns?
    - For http?
    - For buffers?
  - Tool improvements:
    - Get IOCP patch into libevent *

  - Security improvements
    - make is-consensus-fresh-enough check way tighter.
    - If we haven't tried downloading a consensus for ages since we're tired,
      try getting a new one before we use old descriptors for a circuit.
      Related to bug 401. [What does "since we're tired" mean? -RD]

  - Feature removals and deprecations:
    - Get rid of the v1 directory stuff (making, serving, and caching)
      . First verify that the caches won't flip out?
        o If they will, just stop the caches from caching for now
      . perhaps replace it with a "this is a tor server" stock webpage.
        - Get the debs to set DirPortFrontPage in the default.
        - Decide how to handle DirPortFrontPage files with image links.
    - The v2dir flag isn't used for anything anymore, right? If so, dump it.
    - Even clients run rep_hist_load_mtbf_data(). Does this waste memory?
      Dump it?
    - Unless we start using ftime functions, dump them.
    - can we deprecate 'getinfo network-status'?
    - can we deprecate the FastFirstHopPK config option?
    - Can we deprecate controllers that don't use both features?
    - Dump most uint32_t addr functions.

Nice to have for 0.2.1.x:
  - Proposals to write
    - steven's plan for replacing check.torproject.org with a built-in
      answer by tor itself.

  - Documentation
P   - Make documentation realize that location of system configuration file
      will depend on location of system defaults, and isn't always /etc/torrc.

  - Small controller features
    - A status event for when tor decides to stop fetching directory info
      if the client hasn't clicked recently: then make the onion change too.
    - Add a status event when new consensus arrives

  - Windows build
P   - Figure out why dll's compiled in mingw don't work right in WinXP.
P   - create a "make win32-bundle" for vidalia-privoxy-tor-torbutton bundle

  - Refactor bad code:
    - Refactor the HTTP logic so the functions aren't so large.
    - Refactor buf_read and buf_write to have sensible ways to return
      error codes after partial writes
    - Streamline how we pick entry nodes: Make choose_random_entry() have
      less magic and less control logic.
    - Don't call time(NULL) so much; instead have a static time_t field
      that gets updated only a handful of times per second.
    - Move all status info out of routerinfo into local_routerstatus.  Make
      "who can change what" in local_routerstatus explicit.  Make
      local_routerstatus (or equivalent) subsume all places to go for "what
      router is this?"
    - deprecate router_digest_is_trusted_dir() in favor of
      router_get_trusteddirserver_by_digest()

  - Make Tor able to chroot itself
    o allow it to load an entire config file from control interface
    - document LOADCONF
    - log rotation (and FD passing) via control interface
    - chroot yourself, including inhibit trying to read config file
      and reopen logs, unless they are under datadir.

  - Should be trivial:
    - Base relative control socket paths (and other stuff in torrc) on datadir.
    - Tor logs the libevent version on startup, for debugging purposes.
      This is great. But it does this before configuring the logs, so
      it only goes to stdout and is then lost.
    - enforce a lower limit on MaxCircuitDirtiness and CircuitBuildTimeout.
    - Make 'safelogging' extend to info-level logs too.
    - don't do dns hijacking tests if we're reject *:* exit policy?
      (deferred until 0.1.1.x is less common)
    - More consistent error checking in router_parse_entry_from_string().
      I can say "banana" as my bandwidthcapacity, and it won't even squeak.

  d Interface for letting SOAT modify flags that authorities assign.
    (How to keep the authority from clobbering them afterwards?