diff options
| -rw-r--r-- | src/or/dirvote.c | 279 |
1 files changed, 273 insertions, 6 deletions
diff --git a/src/or/dirvote.c b/src/or/dirvote.c index eae3bc8a40..dd36a0f911 100644 --- a/src/or/dirvote.c +++ b/src/or/dirvote.c @@ -50,7 +50,7 @@ static int dirvote_publish_consensus(void); static char *make_consensus_method_list(int low, int high, const char *sep); /** The highest consensus method that we currently support. */ -#define MAX_SUPPORTED_CONSENSUS_METHOD 9 +#define MAX_SUPPORTED_CONSENSUS_METHOD 10 /** Lowest consensus method that contains a 'directory-footer' marker */ #define MIN_METHOD_FOR_FOOTER 9 @@ -766,15 +766,275 @@ networkstatus_check_weights(int64_t Wgg, int64_t Wgd, int64_t Wmg, if (berr) { log_info(LD_DIR, "Bw weight mismatch %d. G="I64_FORMAT" M="I64_FORMAT - " E="I64_FORMAT" D="I64_FORMAT" T="I64_FORMAT, + " E="I64_FORMAT" D="I64_FORMAT" T="I64_FORMAT + " Wmd=%d Wme=%d Wmg=%d Wed=%d Wee=%d" + " Wgd=%d Wgg=%d Wme=%d Wmg=%d", berr, I64_PRINTF_ARG(G), I64_PRINTF_ARG(M), I64_PRINTF_ARG(E), - I64_PRINTF_ARG(D), I64_PRINTF_ARG(T)); + I64_PRINTF_ARG(D), I64_PRINTF_ARG(T), + (int)Wmd, (int)Wme, (int)Wmg, (int)Wed, (int)Wee, + (int)Wgd, (int)Wgg, (int)Wme, (int)Wmg); } return berr; } +/** + * This function computes the bandwidth weights for consensus method 10. + * + * It returns true if weights could be computed, false otherwise. + */ +static int +networkstatus_compute_bw_weights_v10(smartlist_t *chunks, int64_t G, + int64_t M, int64_t E, int64_t D, + int64_t T, int64_t weight_scale) +{ + bw_weights_error_t berr = 0; + int64_t Wgg = -1, Wgd = -1; + int64_t Wmg = -1, Wme = -1, Wmd = -1; + int64_t Wed = -1, Wee = -1; + const char *casename; + char buf[512]; + int r; + + if (G <= 0 || M <= 0 || E <= 0 || D <= 0) { + log_warn(LD_DIR, "Consensus with empty bandwidth: " + "G="I64_FORMAT" M="I64_FORMAT" E="I64_FORMAT + " D="I64_FORMAT" T="I64_FORMAT, + I64_PRINTF_ARG(G), I64_PRINTF_ARG(M), I64_PRINTF_ARG(E), + I64_PRINTF_ARG(D), I64_PRINTF_ARG(T)); + return 0; + } + + /* + * Computed from cases in 3.4.3 of dir-spec.txt + * + * 1. Neither are scarce + * 2. Both Guard and Exit are scarce + * a. R+D <= S + * b. R+D > S + * 3. One of Guard or Exit is scarce + * a. S+D < T/3 + * b. S+D >= T/3 + */ + if (3*E >= T && 3*G >= T) { // E >= T/3 && G >= T/3 + /* Case 1: Neither are scarce. */ + casename = "Case 1 (Wgd=Wmd=Wed)"; + Wgd = weight_scale/3; + Wed = weight_scale/3; + Wmd = weight_scale/3; + Wee = (weight_scale*(E+G+M))/(3*E); + Wme = weight_scale - Wee; + Wmg = (weight_scale*(2*G-E-M))/(3*G); + Wgg = weight_scale - Wmg; + + berr = networkstatus_check_weights(Wgg, Wgd, Wmg, Wme, Wmd, Wee, Wed, + weight_scale, G, M, E, D, T, 10, 1); + + if (berr) { + log_warn(LD_DIR, + "Bw Weights error %d for %s v10. G="I64_FORMAT" M="I64_FORMAT + " E="I64_FORMAT" D="I64_FORMAT" T="I64_FORMAT + " Wmd=%d Wme=%d Wmg=%d Wed=%d Wee=%d" + " Wgd=%d Wgg=%d Wme=%d Wmg=%d weight_scale=%d", + berr, casename, + I64_PRINTF_ARG(G), I64_PRINTF_ARG(M), I64_PRINTF_ARG(E), + I64_PRINTF_ARG(D), I64_PRINTF_ARG(T), + (int)Wmd, (int)Wme, (int)Wmg, (int)Wed, (int)Wee, + (int)Wgd, (int)Wgg, (int)Wme, (int)Wmg, (int)weight_scale); + return 0; + } + } else if (3*E < T && 3*G < T) { // E < T/3 && G < T/3 + int64_t R = MIN(E, G); + int64_t S = MAX(E, G); + /* + * Case 2: Both Guards and Exits are scarce + * Balance D between E and G, depending upon + * D capacity and scarcity. + */ + if (R+D < S) { // Subcase a + Wgg = weight_scale; + Wee = weight_scale; + Wmg = 0; + Wme = 0; + Wmd = 0; + if (E < G) { + casename = "Case 2a (E scarce)"; + Wed = weight_scale; + Wgd = 0; + } else { /* E >= G */ + casename = "Case 2a (G scarce)"; + Wed = 0; + Wgd = weight_scale; + } + } else { // Subcase b: R+D >= S + casename = "Case 2b1 (Wgg=1, Wmd=Wgd)"; + Wee = (weight_scale*(E - G + M))/E; + Wed = (weight_scale*(D - 2*E + 4*G - 2*M))/(3*D); + Wme = (weight_scale*(G-M))/E; + Wmg = 0; + Wgg = weight_scale; + Wmd = (weight_scale - Wed)/2; + Wgd = (weight_scale - Wed)/2; + + berr = networkstatus_check_weights(Wgg, Wgd, Wmg, Wme, Wmd, Wee, Wed, + weight_scale, G, M, E, D, T, 10, 1); + + if (berr) { + casename = "Case 2b2 (Wgg=1, Wee=1)"; + Wgg = weight_scale; + Wee = weight_scale; + Wed = (weight_scale*(D - 2*E + G + M))/(3*D); + Wmd = (weight_scale*(D - 2*M + G + E))/(3*D); + Wme = 0; + Wmg = 0; + + if (Wmd < 0) { // Can happen if M > T/3 + casename = "Case 2b3 (Wmd=0)"; + Wmd = 0; + log_warn(LD_DIR, + "Too much Middle bandwidth on the network to calculate " + "balanced bandwidth-weights. Consider increasing the " + "number of Guard nodes by lowering the requirements."); + } + Wgd = weight_scale - Wed - Wmd; + berr = networkstatus_check_weights(Wgg, Wgd, Wmg, Wme, Wmd, Wee, + Wed, weight_scale, G, M, E, D, T, 10, 1); + } + if (berr != BW_WEIGHTS_NO_ERROR && + berr != BW_WEIGHTS_BALANCE_MID_ERROR) { + log_warn(LD_DIR, + "Bw Weights error %d for %s v10. G="I64_FORMAT" M="I64_FORMAT + " E="I64_FORMAT" D="I64_FORMAT" T="I64_FORMAT + " Wmd=%d Wme=%d Wmg=%d Wed=%d Wee=%d" + " Wgd=%d Wgg=%d Wme=%d Wmg=%d weight_scale=%d", + berr, casename, + I64_PRINTF_ARG(G), I64_PRINTF_ARG(M), I64_PRINTF_ARG(E), + I64_PRINTF_ARG(D), I64_PRINTF_ARG(T), + (int)Wmd, (int)Wme, (int)Wmg, (int)Wed, (int)Wee, + (int)Wgd, (int)Wgg, (int)Wme, (int)Wmg, (int)weight_scale); + return 0; + } + } + } else { // if (E < T/3 || G < T/3) { + int64_t S = MIN(E, G); + // Case 3: Exactly one of Guard or Exit is scarce + if (!(3*E < T || 3*G < T) || !(3*G >= T || 3*E >= T)) { + log_warn(LD_BUG, + "Bw-Weights Case 3 v10 but with G="I64_FORMAT" M=" + I64_FORMAT" E="I64_FORMAT" D="I64_FORMAT" T="I64_FORMAT, + I64_PRINTF_ARG(G), I64_PRINTF_ARG(M), I64_PRINTF_ARG(E), + I64_PRINTF_ARG(D), I64_PRINTF_ARG(T)); + } + + if (3*(S+D) < T) { // Subcase a: S+D < T/3 + if (G < E) { + casename = "Case 3a (G scarce)"; + Wgg = Wgd = weight_scale; + Wmd = Wed = Wmg = 0; + // Minor subcase, if E is more scarce than M, + // keep its bandwidth in place. + if (E < M) Wme = 0; + else Wme = (weight_scale*(E-M))/(2*E); + Wee = weight_scale-Wme; + } else { // G >= E + casename = "Case 3a (E scarce)"; + Wee = Wed = weight_scale; + Wmd = Wgd = Wme = 0; + // Minor subcase, if G is more scarce than M, + // keep its bandwidth in place. + if (G < M) Wmg = 0; + else Wmg = (weight_scale*(G-M))/(2*G); + Wgg = weight_scale-Wmg; + } + } else { // Subcase b: S+D >= T/3 + // D != 0 because S+D >= T/3 + if (G < E) { + casename = "Case 3bg (G scarce, Wgg=1, Wmd == Wed)"; + Wgg = weight_scale; + Wgd = (weight_scale*(D - 2*G + E + M))/(3*D); + Wmg = 0; + Wee = (weight_scale*(E+M))/(2*E); + Wme = weight_scale - Wee; + Wmd = (weight_scale - Wgd)/2; + Wed = (weight_scale - Wgd)/2; + + berr = networkstatus_check_weights(Wgg, Wgd, Wmg, Wme, Wmd, Wee, + Wed, weight_scale, G, M, E, D, T, 10, 1); + } else { // G >= E + casename = "Case 3be (E scarce, Wee=1, Wmd == Wgd)"; + Wee = weight_scale; + Wed = (weight_scale*(D - 2*E + G + M))/(3*D); + Wme = 0; + Wgg = (weight_scale*(G+M))/(2*G); + Wmg = weight_scale - Wgg; + Wmd = (weight_scale - Wed)/2; + Wgd = (weight_scale - Wed)/2; + + berr = networkstatus_check_weights(Wgg, Wgd, Wmg, Wme, Wmd, Wee, + Wed, weight_scale, G, M, E, D, T, 10, 1); + } + if (berr) { + log_warn(LD_DIR, + "Bw Weights error %d for %s v10. G="I64_FORMAT" M="I64_FORMAT + " E="I64_FORMAT" D="I64_FORMAT" T="I64_FORMAT + " Wmd=%d Wme=%d Wmg=%d Wed=%d Wee=%d" + " Wgd=%d Wgg=%d Wme=%d Wmg=%d weight_scale=%d", + berr, casename, + I64_PRINTF_ARG(G), I64_PRINTF_ARG(M), I64_PRINTF_ARG(E), + I64_PRINTF_ARG(D), I64_PRINTF_ARG(T), + (int)Wmd, (int)Wme, (int)Wmg, (int)Wed, (int)Wee, + (int)Wgd, (int)Wgg, (int)Wme, (int)Wmg, (int)weight_scale); + return 0; + } + } + } + + /* We cast down the weights to 32 bit ints on the assumption that + * weight_scale is ~= 10000. We need to ensure a rogue authority + * doesn't break this assumption to rig our weights */ + tor_assert(0 < weight_scale && weight_scale < INT32_MAX); + + /* + * Provide Wgm=Wgg, Wmm=1, Wem=Wee, Weg=Wed. May later determine + * that middle nodes need different bandwidth weights for dirport traffic, + * or that weird exit policies need special weight, or that bridges + * need special weight. + * + * NOTE: This list is sorted. + */ + r = tor_snprintf(buf, sizeof(buf), + "bandwidth-weights Wbd=%d Wbe=%d Wbg=%d Wbm=%d " + "Wdb=%d " + "Web=%d Wed=%d Wee=%d Weg=%d Wem=%d " + "Wgb=%d Wgd=%d Wgg=%d Wgm=%d " + "Wmb=%d Wmd=%d Wme=%d Wmg=%d Wmm=%d\n", + (int)Wmd, (int)Wme, (int)Wmg, (int)weight_scale, + (int)weight_scale, + (int)weight_scale, (int)Wed, (int)Wee, (int)Wed, (int)Wee, + (int)weight_scale, (int)Wgd, (int)Wgg, (int)Wgg, + (int)weight_scale, (int)Wmd, (int)Wme, (int)Wmg, (int)weight_scale); + if (r<0) { + log_warn(LD_BUG, + "Not enough space in buffer for bandwidth-weights line."); + *buf = '\0'; + return 0; + } + smartlist_add(chunks, tor_strdup(buf)); + + log_notice(LD_CIRC, "Computed bandwidth weights for %s with v10: " + "G="I64_FORMAT" M="I64_FORMAT" E="I64_FORMAT" D="I64_FORMAT + " T="I64_FORMAT, + casename, + I64_PRINTF_ARG(G), I64_PRINTF_ARG(M), I64_PRINTF_ARG(E), + I64_PRINTF_ARG(D), I64_PRINTF_ARG(T)); + return 1; +} +/** + * This function computes the bandwidth weights for consensus method 9. + * + * It has been obsoleted in favor of consensus method 10. + */ static void networkstatus_compute_bw_weights_v9(smartlist_t *chunks, int64_t G, int64_t M, int64_t E, int64_t D, int64_t T, @@ -1064,7 +1324,7 @@ networkstatus_compute_bw_weights_v9(smartlist_t *chunks, int64_t G, int64_t M, *buf = '\0'; } smartlist_add(chunks, tor_strdup(buf)); - log_notice(LD_CIRC, "Computed bandwidth weights for %s: " + log_notice(LD_CIRC, "Computed bandwidth weights for %s with v9: " "G="I64_FORMAT" M="I64_FORMAT" E="I64_FORMAT" D="I64_FORMAT " T="I64_FORMAT, casename, @@ -1101,6 +1361,7 @@ networkstatus_compute_consensus(smartlist_t *votes, const routerstatus_format_type_t rs_format = flavor == FLAV_NS ? NS_V3_CONSENSUS : NS_V3_CONSENSUS_MICRODESC; char *params = NULL; + int added_weights = 0; tor_assert(flavor == FLAV_NS || flavor == FLAV_MICRODESC); tor_assert(total_authorities >= smartlist_len(votes)); @@ -1783,7 +2044,13 @@ networkstatus_compute_consensus(smartlist_t *votes, } } - networkstatus_compute_bw_weights_v9(chunks, G, M, E, D, T, weight_scale); + if (consensus_method < 10) { + networkstatus_compute_bw_weights_v9(chunks, G, M, E, D, T, weight_scale); + added_weights = 1; + } else { + added_weights = networkstatus_compute_bw_weights_v10(chunks, G, M, E, D, + T, weight_scale); + } } /* Add a signature. */ @@ -1873,7 +2140,7 @@ networkstatus_compute_consensus(smartlist_t *votes, return NULL; } // Verify balancing parameters - if (consensus_method >= MIN_METHOD_FOR_BW_WEIGHTS) { + if (consensus_method >= MIN_METHOD_FOR_BW_WEIGHTS && added_weights) { networkstatus_verify_bw_weights(c); } networkstatus_vote_free(c); |