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diff --git a/doc/HACKING/design/03-modules.md b/doc/HACKING/design/03-modules.md deleted file mode 100644 index 93eb9d3089..0000000000 --- a/doc/HACKING/design/03-modules.md +++ /dev/null @@ -1,247 +0,0 @@ - -## Tor's modules ## - -### Generic modules ### - -`buffers.c` -: Implements the `buf_t` buffered data type for connections, and several -low-level data handling functions to handle network protocols on it. - -`channel.c` -: Generic channel implementation. Channels handle sending and receiving cells -among tor nodes. - -`channeltls.c` -: Channel implementation for TLS-based OR connections. Uses `connection_or.c`. - -`circuitbuild.c` -: Code for constructing circuits and choosing their paths. (*Note*: -this module could plausibly be split into handling the client side, -the server side, and the path generation aspects of circuit building.) - -`circuitlist.c` -: Code for maintaining and navigating the global list of circuits. - -`circuitmux.c` -: Generic circuitmux implementation. A circuitmux handles deciding, for a -particular channel, which circuit should write next. - -`circuitmux_ewma.c` -: A circuitmux implementation based on the EWMA (exponentially -weighted moving average) algorithm. - -`circuituse.c` -: Code to actually send and receive data on circuits. - -`command.c` -: Handles incoming cells on channels. - -`config.c` -: Parses options from torrc, and uses them to configure the rest of Tor. - -`confparse.c` -: Generic torrc-style parser. Used to parse torrc and state files. - -`connection.c` -: Generic and common connection tools, and implementation for the simpler -connection types. - -`connection_edge.c` -: Implementation for entry and exit connections. - -`connection_or.c` -: Implementation for OR connections (the ones that send cells over TLS). - -`main.c` -: Principal entry point, main loops, scheduled events, and network -management for Tor. - -`ntmain.c` -: Implements Tor as a Windows service. (Not very well.) - -`onion.c` -: Generic code for generating and responding to CREATE and CREATED -cells, and performing the appropriate onion handshakes. Also contains -code to manage the server-side onion queue. - -`onion_fast.c` -: Implements the old SHA1-based CREATE_FAST/CREATED_FAST circuit -creation handshake. (Now deprecated.) - -`onion_ntor.c` -: Implements the Curve25519-based NTOR circuit creation handshake. - -`onion_tap.c` -: Implements the old RSA1024/DH1024-based TAP circuit creation handshake. (Now -deprecated.) - -`relay.c` -: Handles particular types of relay cells, and provides code to receive, -encrypt, route, and interpret relay cells. - -`scheduler.c` -: Decides which channel/circuit pair is ready to receive the next cell. - -`statefile.c` -: Handles loading and storing Tor's state file. - -`tor_main.c` -: Contains the actual `main()` function. (This is placed in a separate -file so that the unit tests can have their own `main()`.) - - -### Node-status modules ### - -`directory.c` -: Implements the HTTP-based directory protocol, including sending, -receiving, and handling most request types. (*Note*: The client parts -of this, and the generic-HTTP parts of this, could plausibly be split -off.) - -`microdesc.c` -: Implements the compact "microdescriptor" format for keeping track of -what we know about a router. - -`networkstatus.c` -: Code for fetching, storing, and interpreting consensus vote documents. - -`nodelist.c` -: Higher-level view of our knowledge of which Tor servers exist. Each -`node_t` corresponds to a router we know about. - -`routerlist.c` -: Code for storing and retrieving router descriptors and extrainfo -documents. - -`routerparse.c` -: Generic and specific code for parsing all Tor directory information -types. - -`routerset.c` -: Parses and interprets a specification for a set of routers (by IP -range, fingerprint, nickname (deprecated), or country). - - -### Client modules ### - -`addressmap.c` -: Handles client-side associations between one address and another. -These are used to implement client-side DNS caching (NOT RECOMMENDED), -MapAddress directives, Automapping, and more. - -`circpathbias.c` -: Path bias attack detection for circuits: tracks whether -connections made through a particular guard have an unusually high failure rate. - -`circuitstats.c` -: Code to track circuit performance statistics in order to adapt our behavior. -Notably includes an algorithm to track circuit build times. - -`dnsserv.c` -: Implements DNSPort for clients. (Note that in spite of the word -"server" in this module's name, it is used for Tor clients. It -implements a DNS server, not DNS for servers.) - -`entrynodes.c` -: Chooses, monitors, and remembers guard nodes. Also contains some -bridge-related code. - -`torcert.c` -: Code to interpret and generate Ed25519-based certificates. - -### Server modules ### - -`dns.c` -: Server-side DNS code. Handles sending and receiving DNS requests on -exit nodes, and implements the server-side DNS cache. - -`dirserv.c` -: Implements part of directory caches that handles responding to -client requests. - -`ext_orport.c` -: Implements the extended ORPort protocol for communication between -server-side pluggable transports and Tor servers. - -`hibernate.c` -: Performs bandwidth accounting, and puts Tor relays into hibernation -when their bandwidth is exhausted. - -`router.c` -: Management code for running a Tor server. In charge of RSA key -maintenance, descriptor generation and uploading. - -`routerkeys.c` -: Key handling code for a Tor server. (Currently handles only the -Ed25519 keys, but the RSA keys could be moved here too.) - - -### Onion service modules ### - -`rendcache.c` -: Stores onion service descriptors. - -`rendclient.c` -: Client-side implementation of the onion service protocol. - -`rendcommon.c` -: Parts of the onion service protocol that are shared by clients, -services, and/or Tor servers. - -`rendmid.c` -: Tor-server-side implementation of the onion service protocol. (Handles -acting as an introduction point or a rendezvous point.) - -`rendservice.c` -: Service-side implementation of the onion service protocol. - -`replaycache.c` -: Backend to check introduce2 requests for replay attempts. - - -### Authority modules ### - -`dircollate.c` -: Helper for `dirvote.c`: Given a set of votes, each containing a list -of Tor nodes, determines which entries across all the votes correspond -to the same nodes, and yields them in a useful order. - -`dirvote.c` -: Implements the directory voting algorithms that authorities use. - -`keypin.c` -: Implements a persistent key-pinning mechanism to tie RSA1024 -identities to ed25519 identities. - -### Miscellaneous modules ### - -`control.c` -: Implements the Tor controller protocol. - -`cpuworker.c` -: Implements the inner work queue function. We use this to move the -work of circuit creation (on server-side) to other CPUs. - -`fp_pair.c` -: Types for handling 2-tuples of 20-byte fingerprints. - -`geoip.c` -: Parses geoip files (which map IP addresses to country codes), and -performs lookups on the internal geoip table. Also stores some -geoip-related statistics. - -`policies.c` -: Parses and implements Tor exit policies. - -`reasons.c` -: Maps internal reason-codes to human-readable strings. - -`rephist.c` -: Tracks Tor servers' performance over time. - -`status.c` -: Writes periodic "heartbeat" status messages about the state of the Tor -process. - -`transports.c` -: Implements management for the pluggable transports subsystem. |