[tor-commits] [tor/master] Refactor parameter computation and add a helper function
nickm at torproject.org
nickm at torproject.org
Fri Jul 1 19:35:16 UTC 2016
commit 6927467bef1b5c46b85d30ac77b364ed407f6d72
Author: Nick Mathewson <nickm at torproject.org>
Date: Mon May 9 20:10:43 2016 -0400
Refactor parameter computation and add a helper function
This patch makes us retain the intermediate list of K=V entries for
the duration of computing our vote, and lets us use that list with
a new function in order to look up parameters before the consensus
is published.
We can't actually use this function yet because of #19011: our
existing code to do this doesn't actually work, and we'll need a new
consensus method to start using it.
Closes ticket #19012.
---
src/or/dirvote.c | 60 ++++++++++++++++++++++++++++++++++++++++-------------
src/or/dirvote.h | 6 +++++-
src/test/test_dir.c | 14 +++++++++++++
3 files changed, 65 insertions(+), 15 deletions(-)
diff --git a/src/or/dirvote.c b/src/or/dirvote.c
index 5071331..4ebea32 100644
--- a/src/or/dirvote.c
+++ b/src/or/dirvote.c
@@ -618,15 +618,47 @@ compute_consensus_versions_list(smartlist_t *lst, int n_versioning)
return result;
}
+/** Given a list of K=V values, return the int32_t value corresponding to
+ * KEYWORD=, or default_val if no such value exists, or if the value is
+ * corrupt.
+ */
+STATIC int32_t
+dirvote_get_intermediate_param_value(const smartlist_t *param_list,
+ const char *keyword,
+ int32_t default_val)
+{
+ unsigned int n_found = 0;
+ int32_t value = default_val;
+
+ SMARTLIST_FOREACH_BEGIN(param_list, const char *, k_v_pair) {
+ if (!strcmpstart(k_v_pair, keyword) && k_v_pair[strlen(keyword)] == '=') {
+ const char *integer_str = &k_v_pair[strlen(keyword)+1];
+ int ok;
+ value = (int32_t)
+ tor_parse_long(integer_str, 10, INT32_MIN, INT32_MAX, &ok, NULL);
+ if (BUG(! ok))
+ return default_val;
+ ++n_found;
+ }
+ } SMARTLIST_FOREACH_END(k_v_pair);
+
+ if (n_found == 1)
+ return value;
+ else if (BUG(n_found > 1))
+ return default_val;
+ else
+ return default_val;
+}
+
/** Minimum number of directory authorities voting for a parameter to
* include it in the consensus, if consensus method 12 or later is to be
* used. See proposal 178 for details. */
#define MIN_VOTES_FOR_PARAM 3
-/** Helper: given a list of valid networkstatus_t, return a new string
+/** Helper: given a list of valid networkstatus_t, return a new smartlist
* containing the contents of the consensus network parameter set.
*/
-STATIC char *
+STATIC smartlist_t *
dirvote_compute_params(smartlist_t *votes, int method, int total_authorities)
{
int i;
@@ -635,7 +667,6 @@ dirvote_compute_params(smartlist_t *votes, int method, int total_authorities)
int cur_param_len;
const char *cur_param;
const char *eq;
- char *result;
const int n_votes = smartlist_len(votes);
smartlist_t *output;
@@ -657,8 +688,7 @@ dirvote_compute_params(smartlist_t *votes, int method, int total_authorities)
if (smartlist_len(param_list) == 0) {
tor_free(vals);
- smartlist_free(param_list);
- return NULL;
+ return param_list;
}
smartlist_sort_strings(param_list);
@@ -706,12 +736,9 @@ dirvote_compute_params(smartlist_t *votes, int method, int total_authorities)
}
} SMARTLIST_FOREACH_END(param);
- result = smartlist_join_strings(output, " ", 0, NULL);
- SMARTLIST_FOREACH(output, char *, cp, tor_free(cp));
- smartlist_free(output);
smartlist_free(param_list);
tor_free(vals);
- return result;
+ return output;
}
#define RANGE_CHECK(a,b,c,d,e,f,g,mx) \
@@ -1158,6 +1185,8 @@ networkstatus_compute_consensus(smartlist_t *votes,
char *packages = NULL;
int added_weights = 0;
dircollator_t *collator = NULL;
+ smartlist_t *param_list = NULL;
+
tor_assert(flavor == FLAV_NS || flavor == FLAV_MICRODESC);
tor_assert(total_authorities >= smartlist_len(votes));
tor_assert(total_authorities > 0);
@@ -1302,9 +1331,10 @@ networkstatus_compute_consensus(smartlist_t *votes,
tor_free(flaglist);
}
- params = dirvote_compute_params(votes, consensus_method,
- total_authorities);
- if (params) {
+ param_list = dirvote_compute_params(votes, consensus_method,
+ total_authorities);
+ if (smartlist_len(param_list)) {
+ params = smartlist_join_strings(param_list, " ", 0, NULL);
smartlist_add(chunks, tor_strdup("params "));
smartlist_add(chunks, params);
smartlist_add(chunks, tor_strdup("\n"));
@@ -1369,7 +1399,7 @@ networkstatus_compute_consensus(smartlist_t *votes,
if (consensus_method >= MIN_METHOD_TO_CLIP_UNMEASURED_BW) {
char *max_unmeasured_param = NULL;
- /* XXXX Extract this code into a common function */
+ /* XXXX Extract this code into a common function. Or don't! see #19011 */
if (params) {
if (strcmpstart(params, "maxunmeasuredbw=") == 0)
max_unmeasured_param = params;
@@ -1924,7 +1954,7 @@ networkstatus_compute_consensus(smartlist_t *votes,
// Parse params, extract BW_WEIGHT_SCALE if present
// DO NOT use consensus_param_bw_weight_scale() in this code!
// The consensus is not formed yet!
- /* XXXX Extract this code into a common function */
+ /* XXXX Extract this code into a common function. Or not: #19011. */
if (params) {
if (strcmpstart(params, "bwweightscale=") == 0)
bw_weight_param = params;
@@ -2044,6 +2074,8 @@ networkstatus_compute_consensus(smartlist_t *votes,
smartlist_free(flags);
SMARTLIST_FOREACH(chunks, char *, cp, tor_free(cp));
smartlist_free(chunks);
+ SMARTLIST_FOREACH(param_list, char *, cp, tor_free(cp));
+ smartlist_free(param_list);
return result;
}
diff --git a/src/or/dirvote.h b/src/or/dirvote.h
index 4c563aa..2a83802 100644
--- a/src/or/dirvote.h
+++ b/src/or/dirvote.h
@@ -210,9 +210,13 @@ document_signature_t *voter_get_sig_by_algorithm(
digest_algorithm_t alg);
#ifdef DIRVOTE_PRIVATE
+STATIC int32_t dirvote_get_intermediate_param_value(
+ const smartlist_t *param_list,
+ const char *keyword,
+ int32_t default_val);
STATIC char *format_networkstatus_vote(crypto_pk_t *private_key,
networkstatus_t *v3_ns);
-STATIC char *dirvote_compute_params(smartlist_t *votes, int method,
+STATIC smartlist_t *dirvote_compute_params(smartlist_t *votes, int method,
int total_authorities);
STATIC char *compute_consensus_package_lines(smartlist_t *votes);
STATIC char *make_consensus_method_list(int low, int high, const char *sep);
diff --git a/src/test/test_dir.c b/src/test/test_dir.c
index b0ae2d9..1f1b300 100644
--- a/src/test/test_dir.c
+++ b/src/test/test_dir.c
@@ -1436,6 +1436,19 @@ test_dir_measured_bw_kb_cache(void *arg)
return;
}
+static char *
+my_dirvote_compute_params(smartlist_t *votes, int method, int total_authorities)
+{
+ smartlist_t *s = dirvote_compute_params(votes, method, total_authorities);
+ tor_assert(s);
+ char *res = smartlist_join_strings(s, " ", 0, NULL);
+ SMARTLIST_FOREACH(s, char *, cp, tor_free(cp));
+ smartlist_free(s);
+ return res;
+}
+
+#define dirvote_compute_params my_dirvote_compute_params
+
static void
test_dir_param_voting(void *arg)
{
@@ -4298,6 +4311,7 @@ struct testcase_t dir_tests[] = {
DIR_LEGACY(measured_bw_kb),
DIR_LEGACY(measured_bw_kb_cache),
DIR_LEGACY(param_voting),
+ DIR(param_voting_lookup, 0),
DIR_LEGACY(v3_networkstatus),
DIR(random_weighted, 0),
DIR(scale_bw, 0),
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