tor-parallel-relay-conn/doc/TODO

make connection_flush_buf() more obviously obsolete
let hup reread the config file, eg so we can get new exit policies without restarting
use times(2) rather than gettimeofday to measure how long it takes to process a cell

Legend:
SPEC!!  - Not specified
SPEC    - Spec not finalized
NICK    - nick claims
ARMA    - arma claims
        - Not done
        * Top priority
        . Partially done
        o Done
        D Deferred
        X Abandoned

Short-term:
        o routers have identity key, link key, onion key.
                o link key certs are
                  D signed by identity key
                  D not in descriptor
                  o not in config
                  D not on disk
                o identity and onion keys are in descriptor (and disk)
        o upon boot, if it doesn't find identity key, generate it and write it.
        o also write a file with the identity key fingerprint in it
        o router generates descriptor: flesh out router_get_my_descriptor()
        o Routers sign descriptors with identity key
        o routers put version number in descriptor
        o routers should maybe have `uname -a` in descriptor?
        o Give nicknames to routers
                o in config
                o in descriptors
        o router posts descriptor
                o when it boots
                D when it changes
        o change tls stuff so certs don't get written to disk, or read from disk
        o make directory.c 'thread'safe
        o dirserver parses descriptor
        o dirserver checks signature
        D client checks signature?
        o dirserver writes directory to file
          o reads that file upon boot
        o directory includes all routers, up and down
        o add "up" line to directory, listing nicknames
ARMA    . find an application that uses half-open connections: openssh
        o instruments ORs to report stats
          o average cell fullness
          o average bandwidth used
        . integrate rep_ok functions, see what breaks
ARMA    - configure log files. separate log file, separate severities.
ARMA    - what assumptions break if we fclose(0) when we daemonize?
        o make buffer struct elements opaque outside buffers.c
ARMA    . Go through log messages, reduce confusing error messages.
ARMA    . make the logs include more info (fd, etc)
ARMA    . add log convention to the HACKING file
        - make 'make install' do the right thing
        o change binary name to tor
        o change config files so you look at commandline, else look in
          /etc/torrc. no cascading.
        o have an absolute datadir with fixed names for files, and fixed-name
          keydir under that with fixed names
ARMA    - tor faq
          list all other systems, why we're different.
        o Move (most of) the router/directory code out of main.c

Mid-term:
        . migrate to using nickname rather than addr:port for routers
                o decide_aci_type
                - generate onion skins
                  - circuit_send_next_onion_skin
                  - circuit_extend
                  - onion_generate_cpath
                - get_unique_aci_by_addr_port
                - circ->n_addr and circ->n_port
                  - circuit_enumerate_by_naddr_nport
                - cpath layers
                - connection_or_connect
                - connection_exact_get_by_addr_port
                - connection_twin_get_by_addr_port
                - router_get_by_addr_port
                - connection_or_init_conn_from_router
                - tag_pack, tag_unpack, connection_cpu_process_inbuf
                - directory_initiate_command
        . Redo scheduler
                o fix SSL_read bug for buffered records
                - make round-robining more fair
        - What happens when a circuit's length is 1? What breaks?
        . streams / circuits
                o Implement streams
                o Rotate circuits after N minutes?
                X Circuits should expire when circuit->expire triggers
NICK            . Handle half-open connections
                        o Figure out what causes connections to close, standardize
                          when we mark a connection vs when we tear it down
                o Look at what ssl does to keep from mutating data streams
ARMA    - Reduce streamid footprint from 7 bytes to 2 bytes
                - Check for collisions in streamid (now possible with
                  just 2 bytes), and back up & replace with padding if so
                - Use the 3 saved bytes to put pseudorandomness in each relay cell
                - Use the 4 reserved bytes in each cell header to keep 1/5
                  of a sha1 of the relay payload (move into stream header)
                - Move length into the stream header too
                - Spec the stream_id stuff. Clarify that nobody on the backward
                  stream should look at stream_id.
ARMA    . Exit policies
                o Spec how to write the exit policies
                - Path selection algorithms
                        - Let user request certain nodes
                        - And disallow certain nodes
                        D Choose path by jurisdiction, etc?
                - Make relay end cells have failure status and payload attached
                - Streams that fail due to exit policy must reextend to new node
                - Add extend_wait state to edge connections, thumb through them
                  when the AP get an extended cell.
SPEC!!  D Non-clique topologies
        D Implement our own memory management, at least for common structs
        . Put CPU workers in separate processes
                o Handle multiple cpu workers (one for each cpu, plus one)
                o Queue for pending tasks if all workers full
                o Support the 'process this onion' task
                D Merge dnsworkers and cpuworkers to some extent
                - Handle cpuworkers dying
        o Simple directory servers
                o Include key in source; sign directories
                        o Signed directory backend
                        o Document
                        o Integrate
                o Add versions to code
                o Have directories list recommended-versions
                        o Include (unused) line in directories
                        o Check for presence of line.
                        o Quit if running the wrong version
                        o Command-line option to override quit
                o Add more information to directory server entries
                        o Exit policies
        D Advanced directory servers
                D Automated reputation management
SPEC!!          D Figure out how to do threshold directory servers
                D jurisdiction info in dirserver entries? other info?
        . Scrubbing proxies
                - Find an smtp proxy?
                        - Check the old smtp proxy code
                o Find an ftp proxy? wget --passive
                D Wait until there are packet redirectors for Linux
                . Get socks4a support into Mozilla
        . Get tor to act like a socks server
                o socks4, socks4a
ARMA            - socks5
SPEC!!          - Handle socks commands other than connect, eg, bind?
        . Develop rendezvous points
                o Design
                - Spec
                - Implement
        D Deploy and manage open source development site.
        . Documentation
                o Discussion of socks, tsocks, etc
                o On-the-network protocol
                        o Onions
                        o Cells
                . Better comments for functions!
        - Tests
                o Testing harness/infrastructure
NICK            . Unit tests
                D System tests (how?)
                - Performance tests, so we know when we've improved
                        . webload infrastructure (Bruce)
                        . httperf infrastructure (easy to set up)
                        . oprofile (installed in RH >8.0)
        D Deploy a widespread network
        D Load balancing between router twins
                D Keep track of load over links/nodes, to
                  know who's hosed
NICK    . Daemonize and package
                o Teach it to fork and background
                - Red Hat spec file
                - Debian spec file equivalent
        . Portability
                . Which .h files are we actually using?
                . Port to:
                        o Linux
                        o BSD
                        . Solaris
                        o Cygwin
                        o Win32
                        o OS X
                - deal with pollhup / reached_eof on all platforms
                o openssl randomness
                o inet_ntoa
                . stdint.h
                - Make a script to set up a local network on your machine
        X Move away from openssl
                o Abstract out crypto calls
                X Look at nss, others? Just include code?
        o Clearer bandwidth management 
                o Do we want to remove bandwidth from OR handshakes?
                o What about OP handshakes?
        - More flexibility in node addressing
                D Support IPv6 rather than just 4
                - Handle multihomed servers (config variable to set IP)
        . Move from onions to ephemeral DH
                o incremental path building
                o transition circuit-level sendmes to hop-level sendmes
                o implement truncate, truncated
                o move from 192byte DH to 128byte DH, so it isn't so damn slow
                - exiting from not-last hop
                        - OP logic to decide to extend/truncate a path
                        - make sure exiting from the not-last hop works
                        - logic to find last *open* hop, not last hop, in cpath
                        - choose exit nodes by exit policies

Older (done) todo stuff:

        o Use a stronger cipher
                o aes now, by including the code ourselves
        X On the fly compression of each stream
        o Clean up the event loop (optimize and sanitize)
        o Remove that awful concept of 'roles'
        o Terminology
                o Circuits, topics, cells stay named that
                o 'Connection' gets divided, or renamed, or something?
        o DNS farm
                o Distribute queries onto the farm, get answers
                o Preemptively grow a new worker before he's needed
                o Prune workers when too many are idle
                o DNS cache   
                        o Clear DNS cache over time  
                        D Honor DNS TTL info (how??)
                o Have strategy when all workers are busy
                o Keep track of which connections are in dns_wait
                o Need to cache positives/negatives on the tor side
                        o Keep track of which queries have been asked
                o Better error handling when
                        o An address doesn't resolve
                        o We have max workers running
                o Consider taking the master out of the loop?
        X Implement reply onions
        o Total rate limiting
        o Look at OR handshake in more detail
                o Spec it
                o Merge OR and OP handshakes
                o rearrange connection_or so it doesn't suck so much to read
                D Periodic link key rotation. Spec?
        o wrap malloc with something that explodes when it fails
        o Clean up the number of places that get to look at prkey