diff options
Diffstat (limited to 'src/or/nodelist.c')
| -rw-r--r-- | src/or/nodelist.c | 231 |
1 files changed, 197 insertions, 34 deletions
diff --git a/src/or/nodelist.c b/src/or/nodelist.c index e0e01ec190..34d1d5f4d7 100644 --- a/src/or/nodelist.c +++ b/src/or/nodelist.c @@ -24,6 +24,23 @@ static void nodelist_drop_node(node_t *node, int remove_from_ht); static void node_free(node_t *node); + +/** count_usable_descriptors counts descriptors with these flag(s) + */ +typedef enum { + /* All descriptors regardless of flags */ + USABLE_DESCRIPTOR_ALL = 0, + /* Only descriptors with the Exit flag */ + USABLE_DESCRIPTOR_EXIT_ONLY = 1 +} usable_descriptor_t; +static void count_usable_descriptors(int *num_present, + int *num_usable, + smartlist_t *descs_out, + const networkstatus_t *consensus, + const or_options_t *options, + time_t now, + routerset_t *in_set, + usable_descriptor_t exit_only); static void update_router_have_minimum_dir_info(void); static double get_frac_paths_needed_for_circs(const or_options_t *options, const networkstatus_t *ns); @@ -1256,20 +1273,28 @@ router_set_status(const char *digest, int up) } /** True iff, the last time we checked whether we had enough directory info - * to build circuits, the answer was "yes". */ + * to build circuits, the answer was "yes". If there are no exits in the + * consensus, we act as if we have 100% of the exit directory info. */ static int have_min_dir_info = 0; + +/** Does the consensus contain nodes that can exit? */ +static consensus_path_type_t have_consensus_path = CONSENSUS_PATH_UNKNOWN; + /** True iff enough has changed since the last time we checked whether we had * enough directory info to build circuits that our old answer can no longer * be trusted. */ static int need_to_update_have_min_dir_info = 1; /** String describing what we're missing before we have enough directory * info. */ -static char dir_info_status[256] = ""; - -/** Return true iff we have enough networkstatus and router information to - * start building circuits. Right now, this means "more than half the - * networkstatus documents, and at least 1/4 of expected routers." */ -//XXX should consider whether we have enough exiting nodes here. +static char dir_info_status[512] = ""; + +/** Return true iff we have enough consensus information to + * start building circuits. Right now, this means "a consensus that's + * less than a day old, and at least 60% of router descriptors (configurable), + * weighted by bandwidth. Treat the exit fraction as 100% if there are + * no exits in the consensus." + * To obtain the final weighted bandwidth, we multiply the + * weighted bandwidth fraction for each position (guard, middle, exit). */ int router_have_minimum_dir_info(void) { @@ -1291,6 +1316,24 @@ router_have_minimum_dir_info(void) return have_min_dir_info; } +/** Set to CONSENSUS_PATH_EXIT if there is at least one exit node + * in the consensus. We update this flag in compute_frac_paths_available if + * there is at least one relay that has an Exit flag in the consensus. + * Used to avoid building exit circuits when they will almost certainly fail. + * Set to CONSENSUS_PATH_INTERNAL if there are no exits in the consensus. + * (This situation typically occurs during bootstrap of a test network.) + * Set to CONSENSUS_PATH_UNKNOWN if we have never checked, or have + * reason to believe our last known value was invalid or has expired. + * If we're in a network with TestingDirAuthVoteExit set, + * this can cause router_have_consensus_path() to be set to + * CONSENSUS_PATH_EXIT, even if there are no nodes with accept exit policies. + */ +consensus_path_type_t +router_have_consensus_path(void) +{ + return have_consensus_path; +} + /** Called when our internal view of the directory has changed. This can be * when the authorities change, networkstatuses change, the list of routerdescs * changes, or number of running routers changes. @@ -1313,20 +1356,23 @@ get_dir_info_status_string(void) /** Iterate over the servers listed in <b>consensus</b>, and count how many of * them seem like ones we'd use, and how many of <em>those</em> we have * descriptors for. Store the former in *<b>num_usable</b> and the latter in - * *<b>num_present</b>. If <b>in_set</b> is non-NULL, only consider those - * routers in <b>in_set</b>. If <b>exit_only</b> is true, only consider nodes - * with the Exit flag. If *descs_out is present, add a node_t for each - * usable descriptor to it. + * *<b>num_present</b>. + * If <b>in_set</b> is non-NULL, only consider those routers in <b>in_set</b>. + * If <b>exit_only</b> is USABLE_DESCRIPTOR_EXIT_ONLY, only consider nodes + * with the Exit flag. + * If *<b>descs_out</b> is present, add a node_t for each usable descriptor + * to it. */ static void count_usable_descriptors(int *num_present, int *num_usable, smartlist_t *descs_out, const networkstatus_t *consensus, const or_options_t *options, time_t now, - routerset_t *in_set, int exit_only) + routerset_t *in_set, + usable_descriptor_t exit_only) { const int md = (consensus->flavor == FLAV_MICRODESC); - *num_present = 0, *num_usable=0; + *num_present = 0, *num_usable = 0; SMARTLIST_FOREACH_BEGIN(consensus->routerstatus_list, routerstatus_t *, rs) { @@ -1334,7 +1380,7 @@ count_usable_descriptors(int *num_present, int *num_usable, if (!node) continue; /* This would be a bug: every entry in the consensus is * supposed to have a node. */ - if (exit_only && ! rs->is_exit) + if (exit_only == USABLE_DESCRIPTOR_EXIT_ONLY && ! rs->is_exit) continue; if (in_set && ! routerset_contains_routerstatus(in_set, rs, -1)) continue; @@ -1358,11 +1404,21 @@ count_usable_descriptors(int *num_present, int *num_usable, log_debug(LD_DIR, "%d usable, %d present (%s%s).", *num_usable, *num_present, - md ? "microdesc" : "desc", exit_only ? " exits" : "s"); + md ? "microdesc" : "desc", + exit_only == USABLE_DESCRIPTOR_EXIT_ONLY ? " exits" : "s"); } /** Return an estimate of which fraction of usable paths through the Tor - * network we have available for use. */ + * network we have available for use. + * Count how many routers seem like ones we'd use, and how many of + * <em>those</em> we have descriptors for. Store the former in + * *<b>num_usable_out</b> and the latter in *<b>num_present_out</b>. + * If **<b>status_out</b> is present, allocate a new string and print the + * available percentages of guard, middle, and exit nodes to it, noting + * whether there are exits in the consensus. + * If there are no guards in the consensus, + * we treat the exit fraction as 100%. + */ static double compute_frac_paths_available(const networkstatus_t *consensus, const or_options_t *options, time_t now, @@ -1375,14 +1431,19 @@ compute_frac_paths_available(const networkstatus_t *consensus, smartlist_t *myexits= smartlist_new(); smartlist_t *myexits_unflagged = smartlist_new(); double f_guard, f_mid, f_exit, f_myexit, f_myexit_unflagged; - int np, nu; /* Ignored */ + double f_path = 0.0; + /* Used to determine whether there are any exits in the consensus */ + int np = 0; + /* Used to determine whether there are any exits with descriptors */ + int nu = 0; const int authdir = authdir_mode_v3(options); count_usable_descriptors(num_present_out, num_usable_out, - mid, consensus, options, now, NULL, 0); + mid, consensus, options, now, NULL, + USABLE_DESCRIPTOR_ALL); if (options->EntryNodes) { count_usable_descriptors(&np, &nu, guards, consensus, options, now, - options->EntryNodes, 0); + options->EntryNodes, USABLE_DESCRIPTOR_ALL); } else { SMARTLIST_FOREACH(mid, const node_t *, node, { if (authdir) { @@ -1395,22 +1456,78 @@ compute_frac_paths_available(const networkstatus_t *consensus, }); } - /* All nodes with exit flag */ + /* All nodes with exit flag + * If we're in a network with TestingDirAuthVoteExit set, + * this can cause false positives on have_consensus_path, + * incorrectly setting it to CONSENSUS_PATH_EXIT. This is + * an unavoidable feature of forcing authorities to declare + * certain nodes as exits. + */ count_usable_descriptors(&np, &nu, exits, consensus, options, now, - NULL, 1); + NULL, USABLE_DESCRIPTOR_EXIT_ONLY); + log_debug(LD_NET, + "%s: %d present, %d usable", + "exits", + np, + nu); + + /* We need at least 1 exit present in the consensus to consider + * building exit paths */ + /* Update our understanding of whether the consensus has exits */ + consensus_path_type_t old_have_consensus_path = have_consensus_path; + have_consensus_path = ((np > 0) ? + CONSENSUS_PATH_EXIT : + CONSENSUS_PATH_INTERNAL); + + if (have_consensus_path == CONSENSUS_PATH_INTERNAL + && old_have_consensus_path != have_consensus_path) { + log_notice(LD_NET, + "The current consensus has no exit nodes. " + "Tor can only build internal paths, " + "such as paths to hidden services."); + + /* However, exit nodes can reachability self-test using this consensus, + * join the network, and appear in a later consensus. This will allow + * the network to build exit paths, such as paths for world wide web + * browsing (as distinct from hidden service web browsing). */ + } + /* All nodes with exit flag in ExitNodes option */ count_usable_descriptors(&np, &nu, myexits, consensus, options, now, - options->ExitNodes, 1); + options->ExitNodes, USABLE_DESCRIPTOR_EXIT_ONLY); + log_debug(LD_NET, + "%s: %d present, %d usable", + "myexits", + np, + nu); + /* Now compute the nodes in the ExitNodes option where which we don't know * what their exit policy is, or we know it permits something. */ count_usable_descriptors(&np, &nu, myexits_unflagged, consensus, options, now, - options->ExitNodes, 0); + options->ExitNodes, USABLE_DESCRIPTOR_ALL); + log_debug(LD_NET, + "%s: %d present, %d usable", + "myexits_unflagged (initial)", + np, + nu); + SMARTLIST_FOREACH_BEGIN(myexits_unflagged, const node_t *, node) { - if (node_has_descriptor(node) && node_exit_policy_rejects_all(node)) + if (node_has_descriptor(node) && node_exit_policy_rejects_all(node)) { SMARTLIST_DEL_CURRENT(myexits_unflagged, node); + /* this node is not actually an exit */ + np--; + /* this node is unusable as an exit */ + nu--; + } } SMARTLIST_FOREACH_END(node); + log_debug(LD_NET, + "%s: %d present, %d usable", + "myexits_unflagged (final)", + np, + nu); + f_guard = frac_nodes_with_descriptors(guards, WEIGHT_FOR_GUARD); f_mid = frac_nodes_with_descriptors(mid, WEIGHT_FOR_MID); f_exit = frac_nodes_with_descriptors(exits, WEIGHT_FOR_EXIT); @@ -1418,6 +1535,12 @@ compute_frac_paths_available(const networkstatus_t *consensus, f_myexit_unflagged= frac_nodes_with_descriptors(myexits_unflagged,WEIGHT_FOR_EXIT); + log_debug(LD_NET, + "f_exit: %.2f, f_myexit: %.2f, f_myexit_unflagged: %.2f", + f_exit, + f_myexit, + f_myexit_unflagged); + /* If our ExitNodes list has eliminated every possible Exit node, and there * were some possible Exit nodes, then instead consider nodes that permit * exiting to some ports. */ @@ -1439,16 +1562,28 @@ compute_frac_paths_available(const networkstatus_t *consensus, if (f_myexit < f_exit) f_exit = f_myexit; + /* if the consensus has no exits, treat the exit fraction as 100% */ + if (router_have_consensus_path() != CONSENSUS_PATH_EXIT) { + f_exit = 1.0; + } + + f_path = f_guard * f_mid * f_exit; + if (status_out) tor_asprintf(status_out, "%d%% of guards bw, " "%d%% of midpoint bw, and " - "%d%% of exit bw", + "%d%% of exit bw%s = " + "%d%% of path bw", (int)(f_guard*100), (int)(f_mid*100), - (int)(f_exit*100)); + (int)(f_exit*100), + (router_have_consensus_path() == CONSENSUS_PATH_EXIT ? + "" : + " (no exits in consensus)"), + (int)(f_path*100)); - return f_guard * f_mid * f_exit; + return f_path; } /** We just fetched a new set of descriptors. Compute how far through @@ -1521,6 +1656,9 @@ update_router_have_minimum_dir_info(void) using_md = consensus->flavor == FLAV_MICRODESC; +#define NOTICE_DIR_INFO_STATUS_INTERVAL (60) + + /* Check fraction of available paths */ { char *status = NULL; int num_present=0, num_usable=0; @@ -1529,16 +1667,37 @@ update_router_have_minimum_dir_info(void) &status); if (paths < get_frac_paths_needed_for_circs(options,consensus)) { - tor_snprintf(dir_info_status, sizeof(dir_info_status), - "We need more %sdescriptors: we have %d/%d, and " - "can only build %d%% of likely paths. (We have %s.)", - using_md?"micro":"", num_present, num_usable, - (int)(paths*100), status); - /* log_notice(LD_NET, "%s", dir_info_status); */ + /* these messages can be excessive in testing networks */ + static ratelim_t last_warned = + RATELIM_INIT(NOTICE_DIR_INFO_STATUS_INTERVAL); + char *suppression_msg = NULL; + if ((suppression_msg = rate_limit_log(&last_warned, time(NULL)))) { + tor_snprintf(dir_info_status, sizeof(dir_info_status), + "We need more %sdescriptors: we have %d/%d, and " + "can only build %d%% of likely paths. (We have %s.)", + using_md?"micro":"", num_present, num_usable, + (int)(paths*100), status); + log_warn(LD_NET, "%s%s", dir_info_status, suppression_msg); + tor_free(suppression_msg); + } tor_free(status); res = 0; control_event_bootstrap(BOOTSTRAP_STATUS_REQUESTING_DESCRIPTORS, 0); goto done; + } else { + /* these messages can be excessive in testing networks */ + static ratelim_t last_warned = + RATELIM_INIT(NOTICE_DIR_INFO_STATUS_INTERVAL); + char *suppression_msg = NULL; + if ((suppression_msg = rate_limit_log(&last_warned, time(NULL)))) { + tor_snprintf(dir_info_status, sizeof(dir_info_status), + "We have enough %sdescriptors: we have %d/%d, and " + "can build %d%% of likely paths. (We have %s.)", + using_md?"micro":"", num_present, num_usable, + (int)(paths*100), status); + log_info(LD_NET, "%s%s", dir_info_status, suppression_msg); + tor_free(suppression_msg); + } } tor_free(status); @@ -1546,12 +1705,16 @@ update_router_have_minimum_dir_info(void) } done: + + /* If paths have just become available in this update. */ if (res && !have_min_dir_info) { log_notice(LD_DIR, "We now have enough directory information to build circuits."); control_event_client_status(LOG_NOTICE, "ENOUGH_DIR_INFO"); control_event_bootstrap(BOOTSTRAP_STATUS_CONN_OR, 0); } + + /* If paths have just become unavailable in this update. */ if (!res && have_min_dir_info) { int quiet = directory_too_idle_to_fetch_descriptors(options, now); tor_log(quiet ? LOG_INFO : LOG_NOTICE, LD_DIR, @@ -1563,7 +1726,7 @@ update_router_have_minimum_dir_info(void) * should only do while circuits are working, like reachability tests * and fetching bridge descriptors only over circuits. */ note_that_we_maybe_cant_complete_circuits(); - + have_consensus_path = CONSENSUS_PATH_UNKNOWN; control_event_client_status(LOG_NOTICE, "NOT_ENOUGH_DIR_INFO"); } have_min_dir_info = res; |