commit 5382b174c5e0c1ba2c285c79ee33bb6caa9fe5cf Author: Nick Mathewson nickm@torproject.org Date: Mon Oct 24 09:21:54 2016 -0400
Module documentation (and an important caveat) for dirvote.c --- src/or/dirvote.c | 45 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-)
diff --git a/src/or/dirvote.c b/src/or/dirvote.c index 2c10e78..4624629 100644 --- a/src/or/dirvote.c +++ b/src/or/dirvote.c @@ -26,6 +26,39 @@ /** * \file dirvote.c * \brief Functions to compute directory consensus, and schedule voting. + * + * This module is the center of the consensus-voting based directory + * authority system. With this system, a set of authorities first + * publish vote based on their opinions of the network, and then compute + * a consensus from those votes. Each authority signs the consensus, + * and clients trust the consensus if enough known authorities have + * signed it. + * + * The code in this module is only invoked on directory authorities. It's + * responsible for: + * + * <ul> + * <li>Generating this authority's vote networkstatus, based on the + * authority's view of the network as represented in dirserv.c + * <li>Formatting the vote networkstatus objects. + * <li>Generating the microdescriptors that correspond to our own + * vote. + * <li>Sending votes to all the other authorities. + * <li>Trying to fetch missing votes from other authorities. + * <li>Computing the consensus from a set of votes, as well as + * a "detached signature" object for other authorities to fetch. + * <li>Collecting other authorities' signatures on the same consensus, + * until there are enough. + * <li>Publishing the consensus to the reset of the directory system. + * <li>Scheduling all of the above operations. + * </ul> + * + * The main entry points are in dirvote_act(), which handles scheduled + * actions; and dirvote_add_vote() and dirvote_add_signatures(), which + * handle uploaded and downloaded votes and signatures. + * + * (See dir-spec.txt from torspec.git for a complete specification of + * the directory protocol and voting algorithms.) **/
/** A consensus that we have built and are appending signatures to. Once it's @@ -1273,7 +1306,17 @@ compute_nth_protocol_set(int n, int n_voters, const smartlist_t *votes) * value in a newly allocated string. * * Note: this function DOES NOT check whether the votes are from - * recognized authorities. (dirvote_add_vote does that.) */ + * recognized authorities. (dirvote_add_vote does that.) + * + * <strong>WATCH OUT</strong>: You need to think before you change the + * behavior of this function, or of the functions it calls! If some + * authorities compute the consensus with a different algorithm than + * others, they will not reach the same result, and they will not all + * sign the same thing! If you really need to change the algorithm + * here, you should allocate a new "consensus_method" for the new + * behavior, and make the new behavior conditional on a new-enough + * consensus_method. + **/ char * networkstatus_compute_consensus(smartlist_t *votes, int total_authorities,