diff options
Diffstat (limited to 'src/or/dircollate.c')
| -rw-r--r-- | src/or/dircollate.c | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/src/or/dircollate.c b/src/or/dircollate.c index c6afd95926..033a7afe0f 100644 --- a/src/or/dircollate.c +++ b/src/or/dircollate.c @@ -8,6 +8,17 @@ * * \brief Collation code for figuring out which identities to vote for in * the directory voting process. + * + * During the consensus calculation, when an authority is looking at the vote + * documents from all the authorities, it needs to compute the consensus for + * each relay listed by at least one authority. But the notion of "each + * relay" can be tricky: some relays have Ed25519 keys, and others don't. + * + * Moreover, older consensus methods did RSA-based ID collation alone, and + * ignored Ed25519 keys. We need to support those too until we're completely + * sure that authorities will never downgrade. + * + * This module is invoked exclusively from dirvote.c. */ #define DIRCOLLATE_PRIVATE @@ -21,6 +32,9 @@ static void dircollator_collate_by_ed25519(dircollator_t *dc); * RSA SHA1 digest) to an array of vote_routerstatus_t. */ typedef struct ddmap_entry_s { HT_ENTRY(ddmap_entry_s) node; + /** A SHA1-RSA1024 identity digest and Ed25519 identity key, + * concatenated. (If there is no ed25519 identity key, there is no + * entry in this table.) */ uint8_t d[DIGEST_LEN + DIGEST256_LEN]; /* The nth member of this array corresponds to the vote_routerstatus_t (if * any) received for this digest pair from the nth voter. */ @@ -43,12 +57,16 @@ ddmap_entry_new(int n_votes) sizeof(vote_routerstatus_t *) * n_votes); } +/** Helper: compute a hash of a single ddmap_entry_t's identity (or + * identities) */ static unsigned ddmap_entry_hash(const ddmap_entry_t *ent) { return (unsigned) siphash24g(ent->d, sizeof(ent->d)); } +/** Helper: return true if <b>a</b> and <b>b</b> have the same + * identity/identities. */ static unsigned ddmap_entry_eq(const ddmap_entry_t *a, const ddmap_entry_t *b) { @@ -56,7 +74,7 @@ ddmap_entry_eq(const ddmap_entry_t *a, const ddmap_entry_t *b) } /** Record the RSA identity of <b>ent</b> as <b>rsa_sha1</b>, and the - * ed25519 identity as <b>ed25519</b>. */ + * ed25519 identity as <b>ed25519</b>. Both must be provided. */ static void ddmap_entry_set_digests(ddmap_entry_t *ent, const uint8_t *rsa_sha1, @@ -72,8 +90,12 @@ HT_GENERATE2(double_digest_map, ddmap_entry_s, node, ddmap_entry_hash, ddmap_entry_eq, 0.6, tor_reallocarray, tor_free_) /** Helper: add a single vote_routerstatus_t <b>vrs</b> to the collator - * <b>dc</b>, indexing it by its RSA key digest, and by the 2-tuple of - * its RSA key digest and Ed25519 key. */ + * <b>dc</b>, indexing it by its RSA key digest, and by the 2-tuple of its RSA + * key digest and Ed25519 key. It must come from the <b>vote_num</b>th + * vote. + * + * Requires that the vote is well-formed -- that is, that it has no duplicate + * routerstatus entries. We already checked for that when parsing the vote. */ static void dircollator_add_routerstatus(dircollator_t *dc, int vote_num, @@ -82,9 +104,12 @@ dircollator_add_routerstatus(dircollator_t *dc, { const char *id = vrs->status.identity_digest; + /* Clear this flag; we might set it later during the voting process */ vrs->ed25519_reflects_consensus = 0; - (void) vote; + (void) vote; // We don't currently need this. + + /* First, add this item to the appropriate RSA-SHA-Id array. */ vote_routerstatus_t **vrs_lst = digestmap_get(dc->by_rsa_sha1, id); if (NULL == vrs_lst) { vrs_lst = tor_calloc(dc->n_votes, sizeof(vote_routerstatus_t *)); @@ -98,6 +123,7 @@ dircollator_add_routerstatus(dircollator_t *dc, if (! vrs->has_ed25519_listing) return; + /* Now add it to the appropriate <Ed,RSA-SHA-Id> array. */ ddmap_entry_t search, *found; memset(&search, 0, sizeof(search)); ddmap_entry_set_digests(&search, (const uint8_t *)id, ed); |