commit fcf906ec7335cf54050ed6d97bc1efea54a0ccfb Author: Nick Mathewson nickm@torproject.org Date: Fri Jan 18 12:56:47 2013 -0500

Add a function to compute fraction of nodes (by weighted bw) with descriptors --- src/or/routerlist.c | 46 ++++++++++++++++++++++++++++++++++++++++++---- src/or/routerlist.h | 4 +++- 2 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/src/or/routerlist.c b/src/or/routerlist.c index 33c0839..5dd1a55 100644 --- a/src/or/routerlist.c +++ b/src/or/routerlist.c @@ -1706,8 +1706,8 @@ smartlist_choose_node_by_bandwidth_weights(const smartlist_t *sl, /** Given a list of routers and a weighting rule as in * smartlist_choose_node_by_bandwidth_weights, compute weighted bandwidth * values for each node and store them in a freshly allocated - * *<b>bandwidths_out</b> of the same length as <b>sl</b>. Return 0 on - * success, -1 on failure. */ + * *<b>bandwidths_out</b> of the same length as <b>sl</b>, and holding results + * as doubles. Return 0 on success, -1 on failure. */ static int compute_weighted_bandwidths(const smartlist_t *sl, bandwidth_weight_rule_t rule, @@ -1859,6 +1859,44 @@ compute_weighted_bandwidths(const smartlist_t *sl, return 0; }

+/** For all nodes in <b>sl</b>, return the fraction of those nodes, weighted + * by their weighted bandwidths with rule <b>rule</b>, for which we have + * descriptors. */ +double +frac_nodes_with_descriptors(const smartlist_t *sl, + bandwidth_weight_rule_t rule) +{ + u64_dbl_t *bandwidths = NULL; + double total, present; + + if (smartlist_len(sl) == 0) + return 0.0; + + if (compute_weighted_bandwidths(sl, rule, &bandwidths) < 0) { + int n_with_descs = 0; + SMARTLIST_FOREACH(sl, const node_t *, node, { + if (node_has_descriptor(node)) + n_with_descs++; + }); + return ((double)n_with_descs) / (double)smartlist_len(sl); + } + + total = present = 0.0; + SMARTLIST_FOREACH_BEGIN(sl, const node_t *, node) { + const double bw = bandwidths[node_sl_idx].dbl; + total += bw; + if (node_has_descriptor(node)) + present += bw; + } SMARTLIST_FOREACH_END(node); + + tor_free(bandwidths); + + if (total < 1.0) + return 0; + + return present / total; +} + /** Helper function: * choose a random node_t element of smartlist <b>sl</b>, weighted by * the advertised bandwidth of each element. @@ -1873,7 +1911,7 @@ compute_weighted_bandwidths(const smartlist_t *sl, * guards proportionally less. */ static const node_t * -smartlist_choose_node_by_bandwidth(smartlist_t *sl, +smartlist_choose_node_by_bandwidth(const smartlist_t *sl, bandwidth_weight_rule_t rule) { unsigned int i; @@ -2079,7 +2117,7 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl, /** Choose a random element of status list <b>sl</b>, weighted by * the advertised bandwidth of each node */ const node_t * -node_sl_choose_by_bandwidth(smartlist_t *sl, +node_sl_choose_by_bandwidth(const smartlist_t *sl, bandwidth_weight_rule_t rule) { /*XXXX MOVE */ const node_t *ret; diff --git a/src/or/routerlist.h b/src/or/routerlist.h index 798cebc..1849fff 100644 --- a/src/or/routerlist.h +++ b/src/or/routerlist.h @@ -47,8 +47,10 @@ const routerinfo_t *routerlist_find_my_routerinfo(void); uint32_t router_get_advertised_bandwidth(const routerinfo_t *router); uint32_t router_get_advertised_bandwidth_capped(const routerinfo_t *router);

-const node_t *node_sl_choose_by_bandwidth(smartlist_t *sl, +const node_t *node_sl_choose_by_bandwidth(const smartlist_t *sl, bandwidth_weight_rule_t rule); +double frac_nodes_with_descriptors(const smartlist_t *sl, + bandwidth_weight_rule_t rule);

const node_t *router_choose_random_node(smartlist_t *excludedsmartlist, struct routerset_t *excludedset,