commit b941f109ac037b270da6f07ffb4947ee237e468a Author: George Kadianakis <desnacked@riseup.net> Date: Thu Jan 29 15:07:35 2015 +0000 Calculate relay weighted bandwidth using guardfraction bandwidths. Now use the guardfraction function to calculate individual relay bandwidth weights. --- src/or/routerlist.c | 42 +++++++++++++++++++++++++++++++++++++++++- 1 file changed, 41 insertions(+), 1 deletion(-) diff --git a/src/or/routerlist.c b/src/or/routerlist.c index fe92ac0..61b2f74 100644 --- a/src/or/routerlist.c +++ b/src/or/routerlist.c @@ -2003,6 +2003,7 @@ compute_weighted_bandwidths(const smartlist_t *sl, double Wg = -1, Wm = -1, We = -1, Wd = -1; double Wgb = -1, Wmb = -1, Web = -1, Wdb = -1; uint64_t weighted_bw = 0; + guardfraction_bandwidth_t guardfraction_bw; u64_dbl_t *bandwidths; /* Can't choose exit and guard at same time */ @@ -2092,6 +2093,8 @@ compute_weighted_bandwidths(const smartlist_t *sl, SMARTLIST_FOREACH_BEGIN(sl, const node_t *, node) { int is_exit = 0, is_guard = 0, is_dir = 0, this_bw = 0; double weight = 1; + double weight_without_guard_flag = 0; /* Used for guardfraction */ + double final_weight = 0; is_exit = node->is_exit && ! node->is_bad_exit; is_guard = node->is_possible_guard; is_dir = node_is_dir(node); @@ -2119,8 +2122,10 @@ compute_weighted_bandwidths(const smartlist_t *sl, if (is_guard && is_exit) { weight = (is_dir ? Wdb*Wd : Wd); + weight_without_guard_flag = (is_dir ? Web*We : We); } else if (is_guard) { weight = (is_dir ? Wgb*Wg : Wg); + weight_without_guard_flag = (is_dir ? Wmb*Wm : Wm); } else if (is_exit) { weight = (is_dir ? Web*We : We); } else { // middle @@ -2132,8 +2137,43 @@ compute_weighted_bandwidths(const smartlist_t *sl, this_bw = 0; if (weight < 0.0) weight = 0.0; + if (weight_without_guard_flag < 0.0) + weight_without_guard_flag = 0.0; - bandwidths[node_sl_idx].dbl = weight*this_bw + 0.5; + /* If guardfraction information is available in the consensus, we + * want to calculate this router's bandwidth according to its + * guardfraction. Quoting from proposal236: + * + * Let Wpf denote the weight from the 'bandwidth-weights' line a + * client would apply to N for position p if it had the guard + * flag, Wpn the weight if it did not have the guard flag, and B the + * measured bandwidth of N in the consensus. Then instead of choosing + * N for position p proportionally to Wpf*B or Wpn*B, clients should + * choose N proportionally to F*Wpf*B + (1-F)*Wpn*B. + */ + if (node->rs && node->rs->has_guardfraction && rule != WEIGHT_FOR_GUARD) { + /* XXX The assert should actually check for is_guard. However, + * that crashes dirauths because of #13297. This should be + * equivalent: */ + tor_assert(node->rs->is_possible_guard); + + guard_get_guardfraction_bandwidth(&guardfraction_bw, + this_bw, + node->rs->guardfraction_percentage); + + /* Calculate final_weight = F*Wpf*B + (1-F)*Wpn*B */ + final_weight = + guardfraction_bw.guard_bw * weight + + guardfraction_bw.non_guard_bw * weight_without_guard_flag; + + log_warn(LD_GENERAL, "%s: Guardfraction weight %f instead of %f (%s)", + node->rs->nickname, final_weight, weight*this_bw, + bandwidth_weight_rule_to_string(rule)); + } else { /* no guardfraction information. calculate the weight normally. */ + final_weight = weight*this_bw; + } + + bandwidths[node_sl_idx].dbl = final_weight + 0.5; } SMARTLIST_FOREACH_END(node); log_debug(LD_CIRC, "Generated weighted bandwidths for rule %s based "