diff options
37 files changed, 3156 insertions, 167 deletions
diff --git a/changes/bug16861 b/changes/bug16861 new file mode 100644 index 0000000000..7fc8d05740 --- /dev/null +++ b/changes/bug16861 @@ -0,0 +1,16 @@ + o Major features (traffic analysis) + - Relays and clients will now send a padding cell on idle OR + connections every 1.5 to 9.5 seconds (tunable via consensus + parameters). Directory connections and inter-relay connections + are not padded. Padding is negotiated using Tor's link protocol, + so both relays and clients must upgrade for this to take effect. + Clients may still send padding despite the relay's version by + setting ConnectionPadding 1 in torrc, and may disable padding + by setting ConnectionPadding 0 in torrc. Padding may be minimized + for mobile users with the torrc option ReducedConnectionPadding. + Implements Proposal 251 and Section 2 of Proposal 254; closes ticket + #16861. + - Relays will publish 24 hour totals of padding and non-padding cell + counts to their extra-info descriptors, unless PaddingStatistics 0 + is set in torrc. These 24 hour totals are also rounded to multiples + of 10000. diff --git a/changes/bug17592 b/changes/bug17592 new file mode 100644 index 0000000000..4b5f22c330 --- /dev/null +++ b/changes/bug17592 @@ -0,0 +1,13 @@ + o Minor bugfixes (connection lifespan) + - Allow more control over how long TLS connections are kept open: unify + CircuitIdleTimeout and PredictedPortsRelevanceTime into a single option + called CircuitsAvailableTimeout. Also, allow the consensus to control + the default values for both this preference, as well as the lifespan + of relay-to-relay connections. Fixes bug #17592. + - Increase the intial circuit build timeout testing frequency, to help + ensure that ReducedConnectionPadding clients finish learning a timeout + before their orconn would expire. The initial testing rate was set back + in the days of TAP and before the Tor Browser updater, when we had to be + much more careful about new clients making lots of circuits. With this + change, a circuit build time is learned in about 15-20 minutes, instead + of ~100-120 minutes. diff --git a/changes/bug17604 b/changes/bug17604 new file mode 100644 index 0000000000..20ac2c38e9 --- /dev/null +++ b/changes/bug17604 @@ -0,0 +1,14 @@ + o Minor bugfixes (connection usage) + - Use NETINFO cells to try to determine if both relays involved in + a connection will agree on the canonical status of that connection. + Prefer the connections where this is the case for extend cells, + and try to close connections where relays disagree on canonical + status early. Also, additionally alter the connection selection + logic to prefer the oldest valid connection for extend cells. + These two changes should reduce the number of long-term connections + that are kept open between relays. Fixes bug #17604. + - Relays will now log hourly statistics on the total number of + connections to other relays. If the number of connections per relay + unexpectedly large, this log message is at notice level. Otherwise + it is at info. + diff --git a/changes/fast_channel_lookup b/changes/fast_channel_lookup new file mode 100644 index 0000000000..7d60fe6ac7 --- /dev/null +++ b/changes/fast_channel_lookup @@ -0,0 +1,2 @@ + o Minor features: + - Add an O(1) implementation of channel_find_by_global_id(). diff --git a/doc/tor.1.txt b/doc/tor.1.txt index 276052c799..1de01162a4 100644 --- a/doc/tor.1.txt +++ b/doc/tor.1.txt @@ -671,8 +671,8 @@ GENERAL OPTIONS [[PredictedPortsRelevanceTime]] **PredictedPortsRelevanceTime** __NUM__:: Set how long, after the client has made an anonymized connection to a given port, we will try to make sure that we build circuits to - exits that support that port. The maximum value for this option is 1 - hour. (Default: 1 hour) + exits that support that port. This option is deprecated. Please use + CircuitsAvailableTimeout instead. [[RunAsDaemon]] **RunAsDaemon** **0**|**1**:: If 1, Tor forks and daemonizes to the background. This option has no effect @@ -819,13 +819,19 @@ The following options are useful only for clients (that is, if LearnCircuitBuildTimeout is 0, this value is the only value used. (Default: 60 seconds) +[[CircuitsAvailableTimeout]] **CircuitsAvailableTimeout** __NUM__:: + Tor will attempt to keep at least one open, unused circuit available for + this amount of time. This option governs how long idle circuits are kept + open, as well as the amount of time Tor will keep a circuit open to each + of the recently used ports. This way when the Tor client is entirely + idle, it can expire all of its circuits, and then expire its TLS + connections. Note that the actual timeout value is uniformly randomized + from the specified value to twice that amount. (Default: 30 minutes; + Max: 24 hours) + [[CircuitIdleTimeout]] **CircuitIdleTimeout** __NUM__:: If we have kept a clean (never used) circuit around for NUM seconds, then - close it. This way when the Tor client is entirely idle, it can expire all - of its circuits, and then expire its TLS connections. Also, if we end up - making a circuit that is not useful for exiting any of the requests we're - receiving, it won't forever take up a slot in the circuit list. (Default: 1 - hour) + close it. This option is deprecated. Use CircuitsAvailableTimeout instead. [[CircuitStreamTimeout]] **CircuitStreamTimeout** __NUM__:: If non-zero, this option overrides our internal timeout schedule for how @@ -842,6 +848,22 @@ The following options are useful only for clients (that is, if and fast enough. The current behavior is simply that Tor is a client unless ORPort, ExtORPort, or DirPort are configured.) (Default: 0) +[[ConnectionPadding]] **ConnectionPadding** **0**|**1**|**auto**:: + This option governs Tor's use of padding to defend against some forms of + traffic analysis. If it is set to 'auto', Tor will send padding only + if both the client and the relay support it. If it is set to 0, Tor will + not send any padding cells. If it is set to 1, Tor will still send padding + for client connections regardless of relay support. Only clients may set + this option. This option should be offered via the UI to mobile users + for use where bandwidth may be expensive. + (Default: auto) + +[[ReducedConnectionPadding]] **ReducedConnectionPadding** **0**|**1**:: + If set to 1, Tor will not not hold OR connections open for very long, + and will send less padding on these connections. Only clients may set + this option. This option should be offered via the UI to mobile users + for use where bandwidth may be expensive. (Default: 0) + [[ExcludeNodes]] **ExcludeNodes** __node__,__node__,__...__:: A list of identity fingerprints, country codes, and address patterns of nodes to avoid when building a circuit. Country codes are @@ -2043,6 +2065,14 @@ is non-zero): If ExtraInfoStatistics is enabled, it will published as part of extra-info document. (Default: 0) +[[PaddingStatistics]] **PaddingStatistics** **0**|**1**:: + Relays only. + When this option is enabled, Tor collects statistics for padding cells + sent and received by this relay, in addition to total cell counts. + These statistics are rounded, and omitted if traffic is low. This + information is important for load balancing decisions related to padding. + (Default: 1) + [[DirReqStatistics]] **DirReqStatistics** **0**|**1**:: Relays and bridges only. When this option is enabled, a Tor directory writes statistics on the diff --git a/src/or/Makefile.nmake b/src/or/Makefile.nmake index 2ac98cd372..429ae67858 100644 --- a/src/or/Makefile.nmake +++ b/src/or/Makefile.nmake @@ -14,6 +14,7 @@ LIBTOR_OBJECTS = \ addressmap.obj \ buffers.obj \ channel.obj \ + channelpadding.obj \ channeltls.obj \ circpathbias.obj \ circuitbuild.obj \ diff --git a/src/or/channel.c b/src/or/channel.c index e79fc0760b..599b00aa6b 100644 --- a/src/or/channel.c +++ b/src/or/channel.c @@ -49,6 +49,7 @@ #include "or.h" #include "channel.h" #include "channeltls.h" +#include "channelpadding.h" #include "circuitbuild.h" #include "circuitlist.h" #include "circuitstats.h" @@ -63,6 +64,7 @@ #include "router.h" #include "routerlist.h" #include "scheduler.h" +#include "compat_time.h" /* Global lists of channels */ @@ -84,6 +86,29 @@ static smartlist_t *active_listeners = NULL; /* All channel_listener_t instances in LISTENING state */ static smartlist_t *finished_listeners = NULL; + +/** Map from channel->global_identifier to channel. Contains the same + * elements as all_channels. */ +HT_HEAD(channel_gid_map, channel_s) channel_gid_map = HT_INITIALIZER(); + +static unsigned +channel_id_hash(const channel_t *chan) +{ + return (unsigned) chan->global_identifier; +} +static int +channel_id_eq(const channel_t *a, const channel_t *b) +{ + return a->global_identifier == b->global_identifier; +} +HT_PROTOTYPE(channel_gid_map, channel_s, gidmap_node, + channel_id_hash, channel_id_eq); +HT_GENERATE2(channel_gid_map, channel_s, gidmap_node, + channel_id_hash, channel_id_eq, + 0.6, tor_reallocarray_, tor_free_); + +HANDLE_IMPL(channel, channel_s,); + /* Counter for ID numbers */ static uint64_t n_channels_allocated = 0; /* @@ -429,6 +454,7 @@ void channel_register(channel_t *chan) { tor_assert(chan); + tor_assert(chan->global_identifier); /* No-op if already registered */ if (chan->registered) return; @@ -443,6 +469,8 @@ channel_register(channel_t *chan) /* Make sure we have all_channels, then add it */ if (!all_channels) all_channels = smartlist_new(); smartlist_add(all_channels, chan); + channel_t *oldval = HT_REPLACE(channel_gid_map, &channel_gid_map, chan); + tor_assert(! oldval); /* Is it finished? */ if (CHANNEL_FINISHED(chan)) { @@ -498,7 +526,9 @@ channel_unregister(channel_t *chan) } /* Get it out of all_channels */ - if (all_channels) smartlist_remove(all_channels, chan); + if (all_channels) smartlist_remove(all_channels, chan); + channel_t *oldval = HT_REMOVE(channel_gid_map, &channel_gid_map, chan); + tor_assert(oldval == NULL || oldval == chan); /* Mark it as unregistered */ chan->registered = 0; @@ -533,7 +563,7 @@ channel_listener_register(channel_listener_t *chan_l) channel_listener_state_to_string(chan_l->state), chan_l->state); - /* Make sure we have all_channels, then add it */ + /* Make sure we have all_listeners, then add it */ if (!all_listeners) all_listeners = smartlist_new(); smartlist_add(all_listeners, chan_l); @@ -578,7 +608,7 @@ channel_listener_unregister(channel_listener_t *chan_l) if (active_listeners) smartlist_remove(active_listeners, chan_l); } - /* Get it out of all_channels */ + /* Get it out of all_listeners */ if (all_listeners) smartlist_remove(all_listeners, chan_l); /* Mark it as unregistered */ @@ -719,15 +749,13 @@ channel_remove_from_digest_map(channel_t *chan) channel_t * channel_find_by_global_id(uint64_t global_identifier) { + channel_t lookup; channel_t *rv = NULL; - if (all_channels && smartlist_len(all_channels) > 0) { - SMARTLIST_FOREACH_BEGIN(all_channels, channel_t *, curr) { - if (curr->global_identifier == global_identifier) { - rv = curr; - break; - } - } SMARTLIST_FOREACH_END(curr); + lookup.global_identifier = global_identifier; + rv = HT_FIND(channel_gid_map, &channel_gid_map, &lookup); + if (rv) { + tor_assert(rv->global_identifier == global_identifier); } return rv; @@ -809,6 +837,83 @@ channel_next_with_rsa_identity(channel_t *chan) } /** + * Relays run this once an hour to look over our list of channels to other + * relays. It prints out some statistics if there are multiple connections + * to many relays. + * + * This function is similar to connection_or_set_bad_connections(), + * and probably could be adapted to replace it, if it was modified to actually + * take action on any of these connections. + */ +void +channel_check_for_duplicates(void) +{ + channel_idmap_entry_t **iter; + channel_t *chan; + int total_relay_connections = 0, total_relays = 0, total_canonical = 0; + int total_half_canonical = 0; + int total_gt_one_connection = 0, total_gt_two_connections = 0; + int total_gt_four_connections = 0; + + HT_FOREACH(iter, channel_idmap, &channel_identity_map) { + int connections_to_relay = 0; + + /* Only consider relay connections */ + if (!connection_or_digest_is_known_relay((char*)(*iter)->digest)) + continue; + + total_relays++; + + for (chan = TOR_LIST_FIRST(&(*iter)->channel_list); chan; + chan = channel_next_with_rsa_identity(chan)) { + + if (CHANNEL_CONDEMNED(chan) || !CHANNEL_IS_OPEN(chan)) + continue; + + connections_to_relay++; + total_relay_connections++; + + if (chan->is_canonical(chan, 0)) total_canonical++; + + if (!chan->is_canonical_to_peer && chan->is_canonical(chan, 0) + && chan->is_canonical(chan, 1)) { + total_half_canonical++; + } + } + + if (connections_to_relay > 1) total_gt_one_connection++; + if (connections_to_relay > 2) total_gt_two_connections++; + if (connections_to_relay > 4) total_gt_four_connections++; + } + +#define MIN_RELAY_CONNECTIONS_TO_WARN 5 + + /* If we average 1.5 or more connections per relay, something is wrong */ + if (total_relays > MIN_RELAY_CONNECTIONS_TO_WARN && + total_relay_connections >= 1.5*total_relays) { + log_notice(LD_OR, + "Your relay has a very large number of connections to other relays. " + "Is your outbound address the same as your relay address? " + "Found %d connections to %d relays. Found %d current canonical " + "connections, in %d of which we were a non-canonical peer. " + "%d relays had more than 1 connection, %d had more than 2, and " + "%d had more than 4 connections.", + total_relay_connections, total_relays, total_canonical, + total_half_canonical, total_gt_one_connection, + total_gt_two_connections, total_gt_four_connections); + } else { + log_info(LD_OR, "Performed connection pruning. " + "Found %d connections to %d relays. Found %d current canonical " + "connections, in %d of which we were a non-canonical peer. " + "%d relays had more than 1 connection, %d had more than 2, and " + "%d had more than 4 connections.", + total_relay_connections, total_relays, total_canonical, + total_half_canonical, total_gt_one_connection, + total_gt_two_connections, total_gt_four_connections); + } +} + +/** * Initialize a channel * * This function should be called by subclasses to set up some per-channel @@ -822,7 +927,7 @@ channel_init(channel_t *chan) tor_assert(chan); /* Assign an ID and bump the counter */ - chan->global_identifier = n_channels_allocated++; + chan->global_identifier = ++n_channels_allocated; /* Init timestamp */ chan->timestamp_last_had_circuits = time(NULL); @@ -861,7 +966,7 @@ channel_init_listener(channel_listener_t *chan_l) tor_assert(chan_l); /* Assign an ID and bump the counter */ - chan_l->global_identifier = n_channels_allocated++; + chan_l->global_identifier = ++n_channels_allocated; /* Timestamp it */ channel_listener_timestamp_created(chan_l); @@ -898,6 +1003,11 @@ channel_free(channel_t *chan) circuitmux_set_policy(chan->cmux, NULL); } + /* Remove all timers and associated handle entries now */ + timer_free(chan->padding_timer); + channel_handle_free(chan->timer_handle); + channel_handles_clear(chan); + /* Call a free method if there is one */ if (chan->free_fn) chan->free_fn(chan); @@ -976,6 +1086,11 @@ channel_force_free(channel_t *chan) circuitmux_set_policy(chan->cmux, NULL); } + /* Remove all timers and associated handle entries now */ + timer_free(chan->padding_timer); + channel_handle_free(chan->timer_handle); + channel_handles_clear(chan); + /* Call a free method if there is one */ if (chan->free_fn) chan->free_fn(chan); @@ -2595,6 +2710,19 @@ channel_do_open_actions(channel_t *chan) } } + /* Disable or reduce padding according to user prefs. */ + if (chan->padding_enabled || get_options()->ConnectionPadding == 1) { + if (!get_options()->ConnectionPadding) { + channelpadding_disable_padding_on_channel(chan); + } + + /* Padding can be forced and/or reduced by clients, regardless of if + * the channel supports it */ + if (get_options()->ReducedConnectionPadding) { + channelpadding_reduce_padding_on_channel(chan); + } + } + circuit_n_chan_done(chan, 1, close_origin_circuits); } @@ -3232,6 +3360,11 @@ channel_free_all(void) /* Geez, anything still left over just won't die ... let it leak then */ HT_CLEAR(channel_idmap, &channel_identity_map); + /* Same with channel_gid_map */ + log_debug(LD_CHANNEL, + "Freeing channel_gid_map"); + HT_CLEAR(channel_gid_map, &channel_gid_map); + log_debug(LD_CHANNEL, "Done cleaning up after channels"); } @@ -3267,22 +3400,20 @@ channel_connect(const tor_addr_t *addr, uint16_t port, */ int -channel_is_better(time_t now, channel_t *a, channel_t *b, - int forgive_new_connections) +channel_is_better(channel_t *a, channel_t *b) { - int a_grace, b_grace; int a_is_canonical, b_is_canonical; - int a_has_circs, b_has_circs; - - /* - * Do not definitively deprecate a new channel with no circuits on it - * until this much time has passed. - */ -#define NEW_CHAN_GRACE_PERIOD (15*60) tor_assert(a); tor_assert(b); + /* If one channel is bad for new circuits, and the other isn't, + * use the one that is still good. */ + if (!channel_is_bad_for_new_circs(a) && channel_is_bad_for_new_circs(b)) + return 1; + if (channel_is_bad_for_new_circs(a) && !channel_is_bad_for_new_circs(b)) + return 0; + /* Check if one is canonical and the other isn't first */ a_is_canonical = channel_is_canonical(a); b_is_canonical = channel_is_canonical(b); @@ -3290,26 +3421,31 @@ channel_is_better(time_t now, channel_t *a, channel_t *b, if (a_is_canonical && !b_is_canonical) return 1; if (!a_is_canonical && b_is_canonical) return 0; + /* Check if we suspect that one of the channels will be preferred + * by the peer */ + if (a->is_canonical_to_peer && !b->is_canonical_to_peer) return 1; + if (!a->is_canonical_to_peer && b->is_canonical_to_peer) return 0; + /* - * Okay, if we're here they tied on canonicity. Next we check if - * they have any circuits, and if one does and the other doesn't, - * we prefer the one that does, unless we are forgiving and the - * one that has no circuits is in its grace period. + * Okay, if we're here they tied on canonicity, the prefer the older + * connection, so that the adversary can't create a new connection + * and try to switch us over to it (which will leak information + * about long-lived circuits). Additionally, switching connections + * too often makes us more vulnerable to attacks like Torscan and + * passive netflow-based equivalents. + * + * Connections will still only live for at most a week, due to + * the check in connection_or_group_set_badness() against + * TIME_BEFORE_OR_CONN_IS_TOO_OLD, which marks old connections as + * unusable for new circuits after 1 week. That check sets + * is_bad_for_new_circs, which is checked in channel_get_for_extend(). + * + * We check channel_is_bad_for_new_circs() above here anyway, for safety. */ + if (channel_when_created(a) < channel_when_created(b)) return 1; + else if (channel_when_created(a) > channel_when_created(b)) return 0; - a_has_circs = (channel_num_circuits(a) > 0); - b_has_circs = (channel_num_circuits(b) > 0); - a_grace = (forgive_new_connections && - (now < channel_when_created(a) + NEW_CHAN_GRACE_PERIOD)); - b_grace = (forgive_new_connections && - (now < channel_when_created(b) + NEW_CHAN_GRACE_PERIOD)); - - if (a_has_circs && !b_has_circs && !b_grace) return 1; - if (!a_has_circs && b_has_circs && !a_grace) return 0; - - /* They tied on circuits too; just prefer whichever is newer */ - - if (channel_when_created(a) > channel_when_created(b)) return 1; + if (channel_num_circuits(a) > channel_num_circuits(b)) return 1; else return 0; } @@ -3334,7 +3470,6 @@ channel_get_for_extend(const char *rsa_id_digest, channel_t *chan, *best = NULL; int n_inprogress_goodaddr = 0, n_old = 0; int n_noncanonical = 0, n_possible = 0; - time_t now = approx_time(); tor_assert(msg_out); tor_assert(launch_out); @@ -3404,7 +3539,7 @@ channel_get_for_extend(const char *rsa_id_digest, continue; } - if (channel_is_better(now, chan, best, 0)) + if (channel_is_better(chan, best)) best = chan; } @@ -4186,8 +4321,12 @@ channel_timestamp_active(channel_t *chan) time_t now = time(NULL); tor_assert(chan); + chan->timestamp_xfer_ms = monotime_coarse_absolute_msec(); chan->timestamp_active = now; + + /* Clear any potential netflow padding timer. We're active */ + chan->next_padding_time_ms = 0; } /** @@ -4270,11 +4409,14 @@ void channel_timestamp_recv(channel_t *chan) { time_t now = time(NULL); - tor_assert(chan); + chan->timestamp_xfer_ms = monotime_coarse_absolute_msec(); chan->timestamp_active = now; chan->timestamp_recv = now; + + /* Clear any potential netflow padding timer. We're active */ + chan->next_padding_time_ms = 0; } /** @@ -4287,11 +4429,15 @@ void channel_timestamp_xmit(channel_t *chan) { time_t now = time(NULL); - tor_assert(chan); + chan->timestamp_xfer_ms = monotime_coarse_absolute_msec(); + chan->timestamp_active = now; chan->timestamp_xmit = now; + + /* Clear any potential netflow padding timer. We're active */ + chan->next_padding_time_ms = 0; } /*************************************************************** diff --git a/src/or/channel.h b/src/or/channel.h index 3d97b8e306..bfcdafb276 100644 --- a/src/or/channel.h +++ b/src/or/channel.h @@ -11,6 +11,8 @@ #include "or.h" #include "circuitmux.h" +#include "timers.h" +#include "handles.h" /* Channel handler function pointer typedefs */ typedef void (*channel_listener_fn_ptr)(channel_listener_t *, channel_t *); @@ -22,6 +24,17 @@ TOR_SIMPLEQ_HEAD(chan_cell_queue, cell_queue_entry_s); typedef struct chan_cell_queue chan_cell_queue_t; /** + * This enum is used by channelpadding to decide when to pad channels. + * Don't add values to it without updating the checks in + * channelpadding_decide_to_pad_channel(). + */ +typedef enum { + CHANNEL_USED_NOT_USED_FOR_FULL_CIRCS = 0, + CHANNEL_USED_FOR_FULL_CIRCS, + CHANNEL_USED_FOR_USER_TRAFFIC, +} channel_usage_info_t; + +/** * Channel struct; see the channel_t typedef in or.h. A channel is an * abstract interface for the OR-to-OR connection, similar to connection_or_t, * but without the strong coupling to the underlying TLS implementation. They @@ -34,11 +47,17 @@ struct channel_s { /** Magic number for type-checking cast macros */ uint32_t magic; + /** List entry for hashtable for global-identifier lookup. */ + HT_ENTRY(channel_s) gidmap_node; + + /** Handle entry for handle-based lookup */ + HANDLE_ENTRY(channel, channel_s); + /** Current channel state */ channel_state_t state; /** Globally unique ID number for a channel over the lifetime of a Tor - * process. + * process. This may not be 0. */ uint64_t global_identifier; @@ -48,6 +67,61 @@ struct channel_s { /** has this channel ever been open? */ unsigned int has_been_open:1; + /** + * This field indicates if the other side has enabled or disabled + * padding via either the link protocol version or + * channelpadding_negotiate cells. + * + * Clients can override this with ConnectionPadding in torrc to + * disable or force padding to relays, but relays cannot override the + * client's request. + */ + unsigned int padding_enabled:1; + + /** Cached value of our decision to pad (to avoid expensive + * checks during critical path statistics counting). */ + unsigned int currently_padding:1; + + /** Is there a pending netflow padding callback? */ + unsigned int pending_padding_callback:1; + + /** Is our peer likely to consider this channel canonical? */ + unsigned int is_canonical_to_peer:1; + + /** Has this channel ever been used for non-directory traffic? + * Used to decide what channels to pad, and when. */ + channel_usage_info_t channel_usage; + + /** When should we send a cell for netflow padding, in absolute + * milliseconds since monotime system start. 0 means no padding + * is scheduled. */ + uint64_t next_padding_time_ms; + + /** The callback pointer for the padding callbacks */ + tor_timer_t *padding_timer; + /** The handle to this channel (to free on canceled timers) */ + struct channel_handle_t *timer_handle; + + /** + * These two fields specify the minimum and maximum negotiated timeout + * values for inactivity (send or receive) before we decide to pad a + * channel. These fields can be set either via a PADDING_NEGOTIATE cell, + * or the torrc option ReducedConnectionPadding. The consensus parameters + * nf_ito_low and nf_ito_high are used to ensure that padding can only be + * negotiated to be less frequent than what is specified in the consensus. + * (This is done to prevent wingnut clients from requesting excessive + * padding). + * + * The actual timeout value is randomly chosen between these two values + * as per the table in channelpadding_get_netflow_inactive_timeout_ms(), + * after ensuring that these values do not specify lower timeouts than + * the consensus parameters. + * + * If these are 0, we have not negotiated or specified custom padding + * times, and instead use consensus defaults. */ + uint16_t padding_timeout_low_ms; + uint16_t padding_timeout_high_ms; + /** Why did we close? */ enum { @@ -87,6 +161,18 @@ struct channel_s { time_t timestamp_created; /* Channel created */ time_t timestamp_active; /* Any activity */ + /** + * This is a high-resolution monotonic timestamp that marks when we + * believe the channel has actually sent or received data to/from + * the wire. Right now, it is used to determine when we should send + * a padding cell for channelpadding. + * + * XXX: Are we setting timestamp_xfer_ms in the right places to + * accurately reflect actual network data transfer? Or might this be + * very wrong wrt when bytes actually go on the wire? + */ + uint64_t timestamp_xfer_ms; + /* Methods implemented by the lower layer */ /** Free a channel */ @@ -516,9 +602,7 @@ channel_t * channel_get_for_extend(const char *rsa_id_digest, int *launch_out); /* Ask which of two channels is better for circuit-extension purposes */ -int channel_is_better(time_t now, - channel_t *a, channel_t *b, - int forgive_new_connections); +int channel_is_better(channel_t *a, channel_t *b); /** Channel lookups */ @@ -601,6 +685,7 @@ void channel_listener_dump_statistics(channel_listener_t *chan_l, int severity); void channel_listener_dump_transport_statistics(channel_listener_t *chan_l, int severity); +void channel_check_for_duplicates(void); void channel_update_bad_for_new_circs(const char *digest, int force); @@ -630,5 +715,8 @@ int packed_cell_is_destroy(channel_t *chan, const packed_cell_t *packed_cell, circid_t *circid_out); +/* Declare the handle helpers */ +HANDLE_DECL(channel, channel_s,); + #endif diff --git a/src/or/channelpadding.c b/src/or/channelpadding.c new file mode 100644 index 0000000000..2370827fff --- /dev/null +++ b/src/or/channelpadding.c @@ -0,0 +1,746 @@ +/* Copyright (c) 2001 Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2015, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/* TOR_CHANNEL_INTERNAL_ define needed for an O(1) implementation of + * channelpadding_channel_to_channelinfo() */ +#define TOR_CHANNEL_INTERNAL_ + +#include "or.h" +#include "channel.h" +#include "channelpadding.h" +#include "channeltls.h" +#include "config.h" +#include "networkstatus.h" +#include "connection.h" +#include "connection_or.h" +#include "main.h" +#include "rephist.h" +#include "router.h" +#include "compat_time.h" +#include <event.h> + +STATIC int channelpadding_get_netflow_inactive_timeout_ms(const channel_t *); +STATIC int channelpadding_send_disable_command(channel_t *); +STATIC int64_t channelpadding_compute_time_until_pad_for_netflow(channel_t *); + +/** The total number of pending channelpadding timers */ +static uint64_t total_timers_pending; + +/** These are cached consensus parameters for netflow */ +/** The timeout lower bound that is allowed before sending padding */ +static int consensus_nf_ito_low; +/** The timeout upper bound that is allowed before sending padding */ +static int consensus_nf_ito_high; +/** The timeout lower bound that is allowed before sending reduced padding */ +static int consensus_nf_ito_low_reduced; +/** The timeout upper bound that is allowed before sending reduced padding */ +static int consensus_nf_ito_high_reduced; +/** The connection timeout between relays */ +static int consensus_nf_conntimeout_relays; +/** The connection timeout for client connections */ +static int consensus_nf_conntimeout_clients; +/** Should we pad before circuits are actually used for client data? */ +static int consensus_nf_pad_before_usage; +/** Should we pad relay-to-relay connections? */ +static int consensus_nf_pad_relays; + +#define TOR_MSEC_PER_SEC 1000 +#define TOR_USEC_PER_MSEC 1000 + +/** + * How often do we get called by the connection housekeeping (ie: once + * per second) */ +#define TOR_HOUSEKEEPING_CALLBACK_MSEC 1000 +/** + * Additional extra time buffer on the housekeeping callback, since + * it can be delayed. This extra slack is used to decide if we should + * schedule a timer or wait for the next callback. */ +#define TOR_HOUSEKEEPING_CALLBACK_SLACK_MSEC 100 + +/** + * This macro tells us if either end of the channel is connected to a client. + * (If we're not a server, we're definitely a client. If the channel thinks + * its a client, use that. Then finally verify in the consensus). + */ +#define CHANNEL_IS_CLIENT(chan, options) \ + (!public_server_mode((options)) || (chan)->is_client || \ + !connection_or_digest_is_known_relay((chan)->identity_digest)) + +/** + * This function is called to update cached consensus parameters every time + * there is a consensus update. This allows us to move the consensus param + * search off of the critical path, so it does not need to be evaluated + * for every single connection, every second. + */ +void +channelpadding_new_consensus_params(networkstatus_t *ns) +{ +#define DFLT_NETFLOW_INACTIVE_KEEPALIVE_LOW 1500 +#define DFLT_NETFLOW_INACTIVE_KEEPALIVE_HIGH 9500 +#define DFLT_NETFLOW_INACTIVE_KEEPALIVE_MIN 0 +#define DFLT_NETFLOW_INACTIVE_KEEPALIVE_MAX 60000 + consensus_nf_ito_low = networkstatus_get_param(ns, "nf_ito_low", + DFLT_NETFLOW_INACTIVE_KEEPALIVE_LOW, + DFLT_NETFLOW_INACTIVE_KEEPALIVE_MIN, + DFLT_NETFLOW_INACTIVE_KEEPALIVE_MAX); + consensus_nf_ito_high = networkstatus_get_param(ns, "nf_ito_high", + DFLT_NETFLOW_INACTIVE_KEEPALIVE_HIGH, + consensus_nf_ito_low, + DFLT_NETFLOW_INACTIVE_KEEPALIVE_MAX); + +#define DFLT_NETFLOW_REDUCED_KEEPALIVE_LOW 9000 +#define DFLT_NETFLOW_REDUCED_KEEPALIVE_HIGH 14000 +#define DFLT_NETFLOW_REDUCED_KEEPALIVE_MIN 0 +#define DFLT_NETFLOW_REDUCED_KEEPALIVE_MAX 60000 + consensus_nf_ito_low_reduced = + networkstatus_get_param(ns, "nf_ito_low_reduced", + DFLT_NETFLOW_REDUCED_KEEPALIVE_LOW, + DFLT_NETFLOW_REDUCED_KEEPALIVE_MIN, + DFLT_NETFLOW_REDUCED_KEEPALIVE_MAX); + + consensus_nf_ito_high_reduced = + networkstatus_get_param(ns, "nf_ito_high_reduced", + DFLT_NETFLOW_REDUCED_KEEPALIVE_HIGH, + consensus_nf_ito_low_reduced, + DFLT_NETFLOW_REDUCED_KEEPALIVE_MAX); + +#define CONNTIMEOUT_RELAYS_DFLT (60*60) // 1 hour +#define CONNTIMEOUT_RELAYS_MIN 60 +#define CONNTIMEOUT_RELAYS_MAX (7*24*60*60) // 1 week + consensus_nf_conntimeout_relays = + networkstatus_get_param(ns, "nf_conntimeout_relays", + CONNTIMEOUT_RELAYS_DFLT, + CONNTIMEOUT_RELAYS_MIN, + CONNTIMEOUT_RELAYS_MAX); + +#define CIRCTIMEOUT_CLIENTS_DFLT (30*60) // 30 minutes +#define CIRCTIMEOUT_CLIENTS_MIN 60 +#define CIRCTIMEOUT_CLIENTS_MAX (24*60*60) // 24 hours + consensus_nf_conntimeout_clients = + networkstatus_get_param(ns, "nf_conntimeout_clients", + CIRCTIMEOUT_CLIENTS_DFLT, + CIRCTIMEOUT_CLIENTS_MIN, + CIRCTIMEOUT_CLIENTS_MAX); + + consensus_nf_pad_before_usage = + networkstatus_get_param(ns, "nf_pad_before_usage", 1, 0, 1); + + consensus_nf_pad_relays = + networkstatus_get_param(ns, "nf_pad_relays", 0, 0, 1); +} + +/** + * Get a random netflow inactive timeout keepalive period in milliseconds, + * the range for which is determined by consensus parameters, negotiation, + * configuration, or default values. The consensus parameters enforce the + * minimum possible value, to avoid excessively frequent padding. + * + * The ranges for this value were chosen to be low enough to ensure that + * routers do not emit a new netflow record for a connection due to it + * being idle. + * + * Specific timeout values for major routers are listed in Proposal 251. + * No major router appeared capable of setting an inactive timeout below 10 + * seconds, so we set the defaults below that value, since we can always + * scale back if it ends up being too much padding. + * + * Returns the next timeout period (in milliseconds) after which we should + * send a padding packet, or 0 if padding is disabled. + */ +STATIC int +channelpadding_get_netflow_inactive_timeout_ms(const channel_t *chan) +{ + int low_timeout = consensus_nf_ito_low; + int high_timeout = consensus_nf_ito_high; + int X1, X2; + + if (low_timeout == 0 && low_timeout == high_timeout) + return 0; // No padding + + /* If we have negotiated different timeout values, use those, but + * don't allow them to be lower than the consensus ones */ + if (chan->padding_timeout_low_ms && chan->padding_timeout_high_ms) { + low_timeout = MAX(low_timeout, chan->padding_timeout_low_ms); + high_timeout = MAX(high_timeout, chan->padding_timeout_high_ms); + } + + if (low_timeout == high_timeout) + return low_timeout; // No randomization + + /* + * This MAX() hack is here because we apply the timeout on both the client + * and the server. This creates the situation where the total time before + * sending a packet in either direction is actually + * min(client_timeout,server_timeout). + * + * If X is a random variable uniform from 0..R-1 (where R=high-low), + * then Y=max(X,X) has Prob(Y == i) = (2.0*i + 1)/(R*R). + * + * If we create a third random variable Z=min(Y,Y), then it turns out that + * Exp[Z] ~= Exp[X]. Here's a table: + * + * R Exp[X] Exp[Z] Exp[min(X,X)] Exp[max(X,X)] + * 2000 999.5 1066 666.2 1332.8 + * 3000 1499.5 1599.5 999.5 1999.5 + * 5000 2499.5 2666 1666.2 3332.8 + * 6000 2999.5 3199.5 1999.5 3999.5 + * 7000 3499.5 3732.8 2332.8 4666.2 + * 8000 3999.5 4266.2 2666.2 5332.8 + * 10000 4999.5 5328 3332.8 6666.2 + * 15000 7499.5 7995 4999.5 9999.5 + * 20000 9900.5 10661 6666.2 13332.8 + * + * In other words, this hack makes it so that when both the client and + * the guard are sending this padding, then the averages work out closer + * to the midpoint of the range, making the overhead easier to tune. + * If only one endpoint is padding (for example: if the relay does not + * support padding, but the client has set ConnectionPadding 1; or + * if the relay does support padding, but the client has set + * ReducedConnectionPadding 1), then the defense will still prevent + * record splitting, but with less overhead than the midpoint + * (as seen by the Exp[max(X,X)] column). + * + * To calculate average padding packet frequency (and thus overhead), + * index into the table by picking a row based on R = high-low. Then, + * use the appropriate column (Exp[Z] for two-sided padding, and + * Exp[max(X,X)] for one-sided padding). Finally, take this value + * and add it to the low timeout value. This value is the average + * frequency which padding packets will be sent. + */ + + X1 = crypto_rand_int(high_timeout - low_timeout); + X2 = crypto_rand_int(high_timeout - low_timeout); + return low_timeout + MAX(X1, X2); +} + +/** + * Update this channel's padding settings based on the PADDING_NEGOTIATE + * contents. + * + * Returns -1 on error; 1 on success. + */ +int +channelpadding_update_padding_for_channel(channel_t *chan, + const channelpadding_negotiate_t *pad_vars) +{ + if (pad_vars->version != 0) { + static ratelim_t version_limit = RATELIM_INIT(600); + + log_fn_ratelim(&version_limit,LOG_PROTOCOL_WARN,LD_PROTOCOL, + "Got a PADDING_NEGOTIATE cell with an unknown version. Ignoring."); + return -1; + } + + // We should not allow malicious relays to disable or reduce padding for + // us as clients. In fact, we should only accept this cell at all if we're + // operating as a relay. Bridges should not accept it from relays, either + // (only from their clients). + if ((get_options()->BridgeRelay && + connection_or_digest_is_known_relay(chan->identity_digest)) || + !get_options()->ORPort_set) { + static ratelim_t relay_limit = RATELIM_INIT(600); + + log_fn_ratelim(&relay_limit,LOG_PROTOCOL_WARN,LD_PROTOCOL, + "Got a PADDING_NEGOTIATE from relay at %s (%s). " + "This should not happen.", + chan->get_remote_descr(chan, 0), + hex_str(chan->identity_digest, DIGEST_LEN)); + return -1; + } + + chan->padding_enabled = (pad_vars->command == CHANNELPADDING_COMMAND_START); + + /* Min must not be lower than the current consensus parameter + nf_ito_low. */ + chan->padding_timeout_low_ms = MAX(consensus_nf_ito_low, + pad_vars->ito_low_ms); + + /* Max must not be lower than ito_low_ms */ + chan->padding_timeout_high_ms = MAX(chan->padding_timeout_low_ms, + pad_vars->ito_high_ms); + + log_fn(LOG_INFO,LD_OR, + "Negotiated padding=%d, lo=%d, hi=%d on "U64_FORMAT, + chan->padding_enabled, chan->padding_timeout_low_ms, + chan->padding_timeout_high_ms, + U64_PRINTF_ARG(chan->global_identifier)); + + return 1; +} + +/** + * Sends a CELL_PADDING_NEGOTIATE on the channel to tell the other side not + * to send padding. + * + * Returns -1 on error, 0 on success. + */ +STATIC int +channelpadding_send_disable_command(channel_t *chan) +{ + channelpadding_negotiate_t disable; + cell_t cell; + + tor_assert(BASE_CHAN_TO_TLS(chan)->conn->link_proto >= + MIN_LINK_PROTO_FOR_CHANNEL_PADDING); + + memset(&cell, 0, sizeof(cell_t)); + memset(&disable, 0, sizeof(channelpadding_negotiate_t)); + cell.command = CELL_PADDING_NEGOTIATE; + + channelpadding_negotiate_set_command(&disable, CHANNELPADDING_COMMAND_STOP); + + if (channelpadding_negotiate_encode(cell.payload, CELL_PAYLOAD_SIZE, + &disable) < 0) + return -1; + + if (chan->write_cell(chan, &cell) == 1) + return 0; + else + return -1; +} + +/** + * Sends a CELL_PADDING_NEGOTIATE on the channel to tell the other side to + * resume sending padding at some rate. + * + * Returns -1 on error, 0 on success. + */ +int +channelpadding_send_enable_command(channel_t *chan, uint16_t low_timeout, + uint16_t high_timeout) +{ + channelpadding_negotiate_t enable; + cell_t cell; + + tor_assert(BASE_CHAN_TO_TLS(chan)->conn->link_proto >= + MIN_LINK_PROTO_FOR_CHANNEL_PADDING); + + memset(&cell, 0, sizeof(cell_t)); + memset(&enable, 0, sizeof(channelpadding_negotiate_t)); + cell.command = CELL_PADDING_NEGOTIATE; + + channelpadding_negotiate_set_command(&enable, CHANNELPADDING_COMMAND_START); + channelpadding_negotiate_set_ito_low_ms(&enable, low_timeout); + channelpadding_negotiate_set_ito_high_ms(&enable, high_timeout); + + if (channelpadding_negotiate_encode(cell.payload, CELL_PAYLOAD_SIZE, + &enable) < 0) + return -1; + + if (chan->write_cell(chan, &cell) == 1) + return 0; + else + return -1; +} + +/** + * Sends a CELL_PADDING cell on a channel if it has been idle since + * our callback was scheduled. + * + * This function also clears the pending padding timer and the callback + * flags. + */ +static void +channelpadding_send_padding_cell_for_callback(channel_t *chan) +{ + cell_t cell; + + /* Check that the channel is still valid and open */ + if (!chan || chan->state != CHANNEL_STATE_OPEN) { + if (chan) chan->pending_padding_callback = 0; + log_fn(LOG_INFO,LD_OR, + "Scheduled a netflow padding cell, but connection already closed."); + return; + } + + /* We should have a pending callback flag set. */ + if (BUG(chan->pending_padding_callback == 0)) + return; + + chan->pending_padding_callback = 0; + + if (!chan->next_padding_time_ms || + chan->has_queued_writes(chan)) { + /* We must have been active before the timer fired */ + chan->next_padding_time_ms = 0; + return; + } + + { + uint64_t now = monotime_coarse_absolute_msec(); + + log_fn(LOG_INFO,LD_OR, + "Sending netflow keepalive on "U64_FORMAT" to %s (%s) after " + I64_FORMAT" ms. Delta "I64_FORMAT"ms", + U64_PRINTF_ARG(chan->global_identifier), + safe_str_client(chan->get_remote_descr(chan, 0)), + safe_str_client(hex_str(chan->identity_digest, DIGEST_LEN)), + U64_PRINTF_ARG(now - chan->timestamp_xfer_ms), + U64_PRINTF_ARG(now - chan->next_padding_time_ms)); + } + + /* Clear the timer */ + chan->next_padding_time_ms = 0; + + /* Send the padding cell. This will cause the channel to get a + * fresh timestamp_active */ + memset(&cell, 0, sizeof(cell)); + cell.command = CELL_PADDING; + chan->write_cell(chan, &cell); +} + +/** + * tor_timer callback function for us to send padding on an idle channel. + * + * This function just obtains the channel from the callback handle, ensures + * it is still valid, and then hands it off to + * channelpadding_send_padding_cell_for_callback(), which checks if + * the channel is still idle before sending padding. + */ +static void +channelpadding_send_padding_callback(tor_timer_t *timer, void *args, + const struct monotime_t *time) +{ + channel_t *chan = channel_handle_get((struct channel_handle_t*)args); + (void)timer; (void)time; + + if (chan && CHANNEL_CAN_HANDLE_CELLS(chan)) { + /* Hrmm.. It might be nice to have an equivalent to assert_connection_ok + * for channels. Then we could get rid of the channeltls dependency */ + tor_assert(TO_CONN(BASE_CHAN_TO_TLS(chan)->conn)->magic == + OR_CONNECTION_MAGIC); + assert_connection_ok(TO_CONN(BASE_CHAN_TO_TLS(chan)->conn), approx_time()); + + channelpadding_send_padding_cell_for_callback(chan); + } else { + log_fn(LOG_INFO,LD_OR, + "Channel closed while waiting for timer."); + } + + total_timers_pending--; +} + +/** + * Schedules a callback to send padding on a channel in_ms milliseconds from + * now. + * + * Returns CHANNELPADDING_WONTPAD on error, CHANNELPADDING_PADDING_SENT if we + * sent the packet immediately without a timer, and + * CHANNELPADDING_PADDING_SCHEDULED if we decided to schedule a timer. + */ +static channelpadding_decision_t +channelpadding_schedule_padding(channel_t *chan, int in_ms) +{ + struct timeval timeout; + tor_assert(!chan->pending_padding_callback); + + if (in_ms <= 0) { + chan->pending_padding_callback = 1; + channelpadding_send_padding_cell_for_callback(chan); + return CHANNELPADDING_PADDING_SENT; + } + + timeout.tv_sec = in_ms/TOR_MSEC_PER_SEC; + timeout.tv_usec = (in_ms%TOR_USEC_PER_MSEC)*TOR_USEC_PER_MSEC; + + if (!chan->timer_handle) { + chan->timer_handle = channel_handle_new(chan); + } + + if (chan->padding_timer) { + timer_set_cb(chan->padding_timer, + channelpadding_send_padding_callback, + chan->timer_handle); + } else { + chan->padding_timer = timer_new(channelpadding_send_padding_callback, + chan->timer_handle); + } + timer_schedule(chan->padding_timer, &timeout); + + rep_hist_padding_count_timers(++total_timers_pending); + + chan->pending_padding_callback = 1; + return CHANNELPADDING_PADDING_SCHEDULED; +} + +/** + * Calculates the number of milliseconds from now to schedule a padding cell. + * + * Returns the number of milliseconds from now (relative) to schedule the + * padding callback. If the padding timer is more than 1.1 seconds in the + * future, we return -1, to avoid scheduling excessive callbacks. If padding + * is disabled in the consensus, we return -2. + * + * Side-effects: Updates chan->next_padding_time_ms, storing an (absolute, not + * relative) millisecond representation of when we should send padding, unless + * other activity happens first. This side-effect allows us to avoid + * scheduling a libevent callback until we're within 1.1 seconds of the padding + * time. + */ +#define CHANNELPADDING_TIME_LATER -1 +#define CHANNELPADDING_TIME_DISABLED -2 +STATIC int64_t +channelpadding_compute_time_until_pad_for_netflow(channel_t *chan) +{ + uint64_t long_now = monotime_coarse_absolute_msec(); + + if (!chan->next_padding_time_ms) { + /* If the below line or crypto_rand_int() shows up on a profile, + * we can avoid getting a timeout until we're at least nf_ito_lo + * from a timeout window. That will prevent us from setting timers + * on connections that were active up to 1.5 seconds ago. + * Idle connections should only call this once every 5.5s on average + * though, so that might be a micro-optimization for little gain. */ + int64_t padding_timeout = + channelpadding_get_netflow_inactive_timeout_ms(chan); + + if (!padding_timeout) + return CHANNELPADDING_TIME_DISABLED; + + chan->next_padding_time_ms = padding_timeout + + chan->timestamp_xfer_ms; + } + + /* If the next padding time is beyond the maximum possible consensus value, + * then this indicates a clock jump, so just send padding now. This is + * better than using monotonic time because we want to avoid the situation + * where we wait around forever for monotonic time to move forward after + * a clock jump far into the past. + */ + if (chan->next_padding_time_ms > long_now + + DFLT_NETFLOW_INACTIVE_KEEPALIVE_MAX) { + tor_fragile_assert(); + log_warn(LD_BUG, + "Channel padding timeout scheduled "I64_FORMAT"ms in the future. " + "Did the monotonic clock just jump?", + I64_PRINTF_ARG(chan->next_padding_time_ms - long_now)); + return 0; /* Clock jumped: Send padding now */ + } + + /* If the timeout will expire before the next time we're called (1000ms + from now, plus some slack), then calculate the number of milliseconds + from now which we should send padding, so we can schedule a callback + then. + */ + if (long_now + + (TOR_HOUSEKEEPING_CALLBACK_MSEC + TOR_HOUSEKEEPING_CALLBACK_SLACK_MSEC) + >= chan->next_padding_time_ms) { + int64_t ms_until_pad_for_netflow = chan->next_padding_time_ms - + long_now; + if (ms_until_pad_for_netflow < 0) { + log_warn(LD_BUG, + "Channel padding timeout scheduled "I64_FORMAT"ms in the past. " + "Did the monotonic clock just jump?", + I64_PRINTF_ARG(-ms_until_pad_for_netflow)); + return 0; /* Clock jumped: Send padding now */ + } + + return ms_until_pad_for_netflow; + } + return CHANNELPADDING_TIME_LATER; +} + +/** + * Returns a randomized value for channel idle timeout in seconds. + * The channel idle timeout governs how quickly we close a channel + * after its last circuit has disappeared. + * + * There are three classes of channels: + * 1. Client+non-canonical. These live for 3-4.5 minutes + * 2. relay to relay. These live for 45-75 min by default + * 3. Reduced padding clients. These live for 1.5-2.25 minutes. + * + * Also allows the default relay-to-relay value to be controlled by the + * consensus. + */ +unsigned int +channelpadding_get_channel_idle_timeout(const channel_t *chan, + int is_canonical) +{ + const or_options_t *options = get_options(); + unsigned int timeout; + + /* Non-canonical and client channels only last for 3-4.5 min when idle */ + if (!is_canonical || CHANNEL_IS_CLIENT(chan, options)) { +#define CONNTIMEOUT_CLIENTS_BASE 180 // 3 to 4.5 min + timeout = CONNTIMEOUT_CLIENTS_BASE + + crypto_rand_int(CONNTIMEOUT_CLIENTS_BASE/2); + } else { // Canonical relay-to-relay channels + // 45..75min or consensus +/- 25% + timeout = consensus_nf_conntimeout_relays; + timeout = 3*timeout/4 + crypto_rand_int(timeout/2); + } + + /* If ReducedConnectionPadding is set, we want to halve the duration of + * the channel idle timeout, since reducing the additional time that + * a channel stays open will reduce the total overhead for making + * new channels. This reduction in overhead/channel expense + * is important for mobile users. The option cannot be set by relays. + * + * We also don't reduce any values for timeout that the user explicitly + * set. + */ + if (options->ReducedConnectionPadding + && !options->CircuitsAvailableTimeout) { + timeout /= 2; + } + + return timeout; +} + +/** + * This function controls how long we keep idle circuits open, + * and how long we build predicted circuits. This behavior is under + * the control of channelpadding because circuit availability is the + * dominant factor in channel lifespan, which influences total padding + * overhead. + * + * Returns a randomized number of seconds in a range from + * CircuitsAvailableTimeout to 2*CircuitsAvailableTimeout. This value is halved + * if ReducedConnectionPadding is set. The default value of + * CircuitsAvailableTimeout can be controlled by the consensus. + */ +int +channelpadding_get_circuits_available_timeout(void) +{ + const or_options_t *options = get_options(); + int timeout = options->CircuitsAvailableTimeout; + + if (!timeout) { + timeout = consensus_nf_conntimeout_clients; + + /* If ReducedConnectionPadding is set, we want to halve the duration of + * the channel idle timeout, since reducing the additional time that + * a channel stays open will reduce the total overhead for making + * new connections. This reduction in overhead/connection expense + * is important for mobile users. The option cannot be set by relays. + * + * We also don't reduce any values for timeout that the user explicitly + * set. + */ + if (options->ReducedConnectionPadding) { + // half the value to 15..30min by default + timeout /= 2; + } + } + + // 30..60min by default + timeout = timeout + crypto_rand_int(timeout); + + return timeout; +} + +/** + * Calling this function on a channel causes it to tell the other side + * not to send padding, and disables sending padding from this side as well. + */ +void +channelpadding_disable_padding_on_channel(channel_t *chan) +{ + chan->padding_enabled = 0; + + // Send cell to disable padding on the other end + channelpadding_send_disable_command(chan); +} + +/** + * Calling this function on a channel causes it to tell the other side + * not to send padding, and reduces the rate that padding is sent from + * this side. + */ +void +channelpadding_reduce_padding_on_channel(channel_t *chan) +{ + /* Padding can be forced and reduced by clients, regardless of if + * the channel supports it. So we check for support here before + * sending any commands. */ + if (chan->padding_enabled) { + channelpadding_send_disable_command(chan); + } + + chan->padding_timeout_low_ms = consensus_nf_ito_low_reduced; + chan->padding_timeout_high_ms = consensus_nf_ito_high_reduced; + + log_fn(LOG_INFO,LD_OR, + "Reduced padding on channel "U64_FORMAT": lo=%d, hi=%d", + U64_PRINTF_ARG(chan->global_identifier), + chan->padding_timeout_low_ms, chan->padding_timeout_high_ms); +} + +/** + * This function is called once per second by run_connection_housekeeping(), + * but only if the channel is still open, valid, and non-wedged. + * + * It decides if and when we should send a padding cell, and if needed, + * schedules a callback to send that cell at the appropriate time. + * + * Returns an enum that represents the current padding decision state. + * Return value is currently used only by unit tests. + */ +channelpadding_decision_t +channelpadding_decide_to_pad_channel(channel_t *chan) +{ + const or_options_t *options = get_options(); + + /* Only pad open channels */ + if (chan->state != CHANNEL_STATE_OPEN) + return CHANNELPADDING_WONTPAD; + + if (chan->channel_usage == CHANNEL_USED_FOR_FULL_CIRCS) { + if (!consensus_nf_pad_before_usage) + return CHANNELPADDING_WONTPAD; + } else if (chan->channel_usage != CHANNEL_USED_FOR_USER_TRAFFIC) { + return CHANNELPADDING_WONTPAD; + } + + if (chan->pending_padding_callback) + return CHANNELPADDING_PADDING_ALREADY_SCHEDULED; + + /* Don't pad the channel if we didn't negotiate it, but still + * allow clients to force padding if options->ChannelPadding is + * explicitly set to 1. + */ + if (!chan->padding_enabled && options->ConnectionPadding != 1) { + return CHANNELPADDING_WONTPAD; + } + + if (!chan->has_queued_writes(chan)) { + int is_client_channel = 0; + + if (CHANNEL_IS_CLIENT(chan, options)) { + is_client_channel = 1; + } + + /* If nf_pad_relays=1 is set in the consensus, we pad + * on *all* idle connections, relay-relay or relay-client. + * Otherwise pad only for client+bridge cons */ + if (is_client_channel || consensus_nf_pad_relays) { + int64_t pad_time_ms = + channelpadding_compute_time_until_pad_for_netflow(chan); + + if (pad_time_ms == CHANNELPADDING_TIME_DISABLED) { + return CHANNELPADDING_WONTPAD; + } else if (pad_time_ms == CHANNELPADDING_TIME_LATER) { + chan->currently_padding = 1; + return CHANNELPADDING_PADLATER; + } else { + /* We have to schedule a callback because we're called exactly once per + * second, but we don't want padding packets to go out exactly on an + * integer multiple of seconds. This callback will only be scheduled + * if we're within 1.1 seconds of the padding time. + */ + chan->currently_padding = 1; + return channelpadding_schedule_padding(chan, pad_time_ms); + } + } else { + chan->currently_padding = 0; + return CHANNELPADDING_WONTPAD; + } + } else { + return CHANNELPADDING_PADLATER; + } +} + diff --git a/src/or/channelpadding.h b/src/or/channelpadding.h new file mode 100644 index 0000000000..2708ee9739 --- /dev/null +++ b/src/or/channelpadding.h @@ -0,0 +1,40 @@ +/* Copyright (c) 2001 Matej Pfajfar. + * Copyright (c) 2001-2004, Roger Dingledine. + * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. + * Copyright (c) 2007-2015, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file circuitbuild.h + * \brief Header file for circuitbuild.c. + **/ +#ifndef TOR_CHANNELPADDING_H +#define TOR_CHANNELPADDING_H + +#include "channelpadding_negotiation.h" + +typedef enum { + CHANNELPADDING_WONTPAD, + CHANNELPADDING_PADLATER, + CHANNELPADDING_PADDING_SCHEDULED, + CHANNELPADDING_PADDING_ALREADY_SCHEDULED, + CHANNELPADDING_PADDING_SENT, +} channelpadding_decision_t; + +channelpadding_decision_t channelpadding_decide_to_pad_channel(channel_t + *chan); +int channelpadding_update_padding_for_channel(channel_t *, + const channelpadding_negotiate_t + *chan); + +void channelpadding_disable_padding_on_channel(channel_t *chan); +void channelpadding_reduce_padding_on_channel(channel_t *chan); +int channelpadding_send_enable_command(channel_t *chan, uint16_t low_timeout, + uint16_t high_timeout); + +int channelpadding_get_circuits_available_timeout(void); +unsigned int channelpadding_get_channel_idle_timeout(const channel_t *, int); +void channelpadding_new_consensus_params(networkstatus_t *ns); + +#endif + diff --git a/src/or/channeltls.c b/src/or/channeltls.c index 7c4dc9aa09..4cdd554174 100644 --- a/src/or/channeltls.c +++ b/src/or/channeltls.c @@ -57,6 +57,9 @@ #include "routerlist.h" #include "scheduler.h" #include "torcert.h" +#include "networkstatus.h" +#include "channelpadding_negotiation.h" +#include "channelpadding.h" /** How many CELL_PADDING cells have we received, ever? */ uint64_t stats_n_padding_cells_processed = 0; @@ -122,6 +125,8 @@ static void channel_tls_process_netinfo_cell(cell_t *cell, static int command_allowed_before_handshake(uint8_t command); static int enter_v3_handshake_with_cell(var_cell_t *cell, channel_tls_t *tlschan); +static void channel_tls_process_padding_negotiate_cell(cell_t *cell, + channel_tls_t *chan); /** * Do parts of channel_tls_t initialization common to channel_tls_connect() @@ -734,6 +739,15 @@ channel_tls_matches_target_method(channel_t *chan, return 0; } + /* real_addr is the address this connection came from. + * base_.addr is updated by connection_or_init_conn_from_address() + * to be the address in the descriptor. It may be tempting to + * allow either address to be allowed, but if we did so, it would + * enable someone who steals a relay's keys to impersonate/MITM it + * from anywhere on the Internet! (Because they could make long-lived + * TLS connections from anywhere to all relays, and wait for them to + * be used for extends). + */ return tor_addr_eq(&(tlschan->conn->real_addr), target); } @@ -1098,9 +1112,16 @@ channel_tls_handle_cell(cell_t *cell, or_connection_t *conn) /* We note that we're on the internet whenever we read a cell. This is * a fast operation. */ entry_guards_note_internet_connectivity(get_guard_selection_info()); + rep_hist_padding_count_read(PADDING_TYPE_TOTAL); + + if (TLS_CHAN_TO_BASE(chan)->currently_padding) + rep_hist_padding_count_read(PADDING_TYPE_ENABLED_TOTAL); switch (cell->command) { case CELL_PADDING: + rep_hist_padding_count_read(PADDING_TYPE_CELL); + if (TLS_CHAN_TO_BASE(chan)->currently_padding) + rep_hist_padding_count_read(PADDING_TYPE_ENABLED_CELL); ++stats_n_padding_cells_processed; /* do nothing */ break; @@ -1111,6 +1132,10 @@ channel_tls_handle_cell(cell_t *cell, or_connection_t *conn) ++stats_n_netinfo_cells_processed; PROCESS_CELL(netinfo, cell, chan); break; + case CELL_PADDING_NEGOTIATE: + ++stats_n_netinfo_cells_processed; + PROCESS_CELL(padding_negotiate, cell, chan); + break; case CELL_CREATE: case CELL_CREATE_FAST: case CELL_CREATED: @@ -1566,9 +1591,12 @@ channel_tls_process_versions_cell(var_cell_t *cell, channel_tls_t *chan) /* We set this after sending the verions cell. */ /*XXXXX symbolic const.*/ - chan->base_.wide_circ_ids = + TLS_CHAN_TO_BASE(chan)->wide_circ_ids = chan->conn->link_proto >= MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS; - chan->conn->wide_circ_ids = chan->base_.wide_circ_ids; + chan->conn->wide_circ_ids = TLS_CHAN_TO_BASE(chan)->wide_circ_ids; + + TLS_CHAN_TO_BASE(chan)->padding_enabled = + chan->conn->link_proto >= MIN_LINK_PROTO_FOR_CHANNEL_PADDING; if (send_certs) { if (connection_or_send_certs_cell(chan->conn) < 0) { @@ -1595,6 +1623,43 @@ channel_tls_process_versions_cell(var_cell_t *cell, channel_tls_t *chan) } /** + * Process a 'padding_negotiate' cell + * + * This function is called to handle an incoming PADDING_NEGOTIATE cell; + * enable or disable padding accordingly, and read and act on its timeout + * value contents. + */ +static void +channel_tls_process_padding_negotiate_cell(cell_t *cell, channel_tls_t *chan) +{ + channelpadding_negotiate_t *negotiation; + tor_assert(cell); + tor_assert(chan); + tor_assert(chan->conn); + + if (chan->conn->link_proto < MIN_LINK_PROTO_FOR_CHANNEL_PADDING) { + log_fn(LOG_PROTOCOL_WARN, LD_OR, + "Received a PADDING_NEGOTIATE cell on v%d connection; dropping.", + chan->conn->link_proto); + return; + } + + if (channelpadding_negotiate_parse(&negotiation, cell->payload, + CELL_PAYLOAD_SIZE) < 0) { + log_fn(LOG_PROTOCOL_WARN, LD_OR, + "Received malformed PADDING_NEGOTIATE cell on v%d connection; " + "dropping.", chan->conn->link_proto); + + return; + } + + channelpadding_update_padding_for_channel(TLS_CHAN_TO_BASE(chan), + negotiation); + + channelpadding_negotiate_free(negotiation); +} + +/** * Process a 'netinfo' cell * * This function is called to handle an incoming NETINFO cell; read and act @@ -1611,6 +1676,7 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan) const uint8_t *cp, *end; uint8_t n_other_addrs; time_t now = time(NULL); + const routerinfo_t *me = router_get_my_routerinfo(); long apparent_skew = 0; tor_addr_t my_apparent_addr = TOR_ADDR_NULL; @@ -1693,8 +1759,20 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan) if (my_addr_type == RESOLVED_TYPE_IPV4 && my_addr_len == 4) { tor_addr_from_ipv4n(&my_apparent_addr, get_uint32(my_addr_ptr)); + + if (!get_options()->BridgeRelay && me && + get_uint32(my_addr_ptr) == htonl(me->addr)) { + TLS_CHAN_TO_BASE(chan)->is_canonical_to_peer = 1; + } + } else if (my_addr_type == RESOLVED_TYPE_IPV6 && my_addr_len == 16) { tor_addr_from_ipv6_bytes(&my_apparent_addr, (const char *) my_addr_ptr); + + if (!get_options()->BridgeRelay && me && + !tor_addr_is_null(&me->ipv6_addr) && + tor_addr_eq(&my_apparent_addr, &me->ipv6_addr)) { + TLS_CHAN_TO_BASE(chan)->is_canonical_to_peer = 1; + } } n_other_addrs = (uint8_t) *cp++; @@ -1710,6 +1788,14 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan) connection_or_close_for_error(chan->conn, 0); return; } + /* A relay can connect from anywhere and be canonical, so + * long as it tells you from where it came. This may be a bit + * concerning.. Luckily we have another check in + * channel_tls_matches_target_method() to ensure that extends + * only go to the IP they ask for. + * + * XXX: Bleh. That check is not used if the connection is canonical. + */ if (tor_addr_eq(&addr, &(chan->conn->real_addr))) { connection_or_set_canonical(chan->conn, 1); break; @@ -1718,6 +1804,20 @@ channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan) --n_other_addrs; } + if (me && !TLS_CHAN_TO_BASE(chan)->is_canonical_to_peer && + channel_is_canonical(TLS_CHAN_TO_BASE(chan))) { + log_info(LD_OR, + "We made a connection to a relay at %s (fp=%s) but we think " + "they will not consider this connection canonical. They " + "think we are at %s, but we think its %s.", + safe_str(TLS_CHAN_TO_BASE(chan)->get_remote_descr(TLS_CHAN_TO_BASE(chan), + 0)), + safe_str(hex_str(chan->conn->identity_digest, DIGEST_LEN)), + safe_str(tor_addr_is_null(&my_apparent_addr) ? + "<none>" : fmt_and_decorate_addr(&my_apparent_addr)), + safe_str(fmt_addr32(me->addr))); + } + /* Act on apparent skew. */ /** Warn when we get a netinfo skew with at least this value. */ #define NETINFO_NOTICE_SKEW 3600 diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c index f8b3609757..08827c053b 100644 --- a/src/or/circuitbuild.c +++ b/src/or/circuitbuild.c @@ -939,9 +939,18 @@ circuit_send_next_onion_skin(origin_circuit_t *circ) memset(&cc, 0, sizeof(cc)); if (circ->build_state->onehop_tunnel) control_event_bootstrap(BOOTSTRAP_STATUS_ONEHOP_CREATE, 0); - else + else { control_event_bootstrap(BOOTSTRAP_STATUS_CIRCUIT_CREATE, 0); + /* If this is not a one-hop tunnel, the channel is being used + * for traffic that wants anonymity and protection from traffic + * analysis (such as netflow record retention). That means we want + * to pad it. + */ + if (circ->base_.n_chan->channel_usage < CHANNEL_USED_FOR_FULL_CIRCS) + circ->base_.n_chan->channel_usage = CHANNEL_USED_FOR_FULL_CIRCS; + } + node = node_get_by_id(circ->base_.n_chan->identity_digest); fast = should_use_create_fast_for_circuit(circ); if (!fast) { diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c index 365e5b2f89..5761890924 100644 --- a/src/or/circuitlist.c +++ b/src/or/circuitlist.c @@ -78,6 +78,7 @@ #include "rephist.h" #include "routerlist.h" #include "routerset.h" +#include "channelpadding.h" #include "ht.h" @@ -814,6 +815,11 @@ init_circuit_base(circuit_t *circ) circ->global_circuitlist_idx = smartlist_len(circuit_get_global_list()) - 1; } +/** If we haven't yet decided on a good timeout value for circuit + * building, we close idle circuits aggressively so we can get more + * data points. */ +#define IDLE_TIMEOUT_WHILE_LEARNING (1*60) + /** Allocate space for a new circuit, initializing with <b>p_circ_id</b> * and <b>p_conn</b>. Add it to the global circuit list. */ @@ -841,6 +847,41 @@ origin_circuit_new(void) circuit_build_times_update_last_circ(get_circuit_build_times_mutable()); + if (! circuit_build_times_disabled(get_options()) && + circuit_build_times_needs_circuits(get_circuit_build_times())) { + /* Circuits should be shorter lived if we need more of them + * for learning a good build timeout */ + circ->circuit_idle_timeout = IDLE_TIMEOUT_WHILE_LEARNING; + } else { + // This should always be larger than the current port prediction time + // remaining, or else we'll end up with the case where a circuit times out + // and another one is built, effectively doubling the timeout window. + // + // We also randomize it by up to 5% more (ie 5% of 0 to 3600 seconds, + // depending on how much circuit prediction time is remaining) so that + // we don't close a bunch of unused circuits all at the same time. + int prediction_time_remaining = + predicted_ports_prediction_time_remaining(time(NULL)); + circ->circuit_idle_timeout = prediction_time_remaining+1+ + crypto_rand_int(1+prediction_time_remaining/20); + + if (circ->circuit_idle_timeout <= 0) { + log_warn(LD_BUG, + "Circuit chose a negative idle timeout of %d based on " + "%d seconds of predictive building remaining.", + circ->circuit_idle_timeout, + prediction_time_remaining); + circ->circuit_idle_timeout = IDLE_TIMEOUT_WHILE_LEARNING; + } + + log_info(LD_CIRC, + "Circuit " U64_FORMAT " chose an idle timeout of %d based on " + "%d seconds of predictive building remaining.", + U64_PRINTF_ARG(circ->global_identifier), + circ->circuit_idle_timeout, + prediction_time_remaining); + } + return circ; } diff --git a/src/or/circuituse.c b/src/or/circuituse.c index 8d233e0cb6..03b28c6ebd 100644 --- a/src/or/circuituse.c +++ b/src/or/circuituse.c @@ -1383,11 +1383,6 @@ circuit_detach_stream(circuit_t *circ, edge_connection_t *conn) tor_fragile_assert(); } -/** If we haven't yet decided on a good timeout value for circuit - * building, we close idles circuits aggressively so we can get more - * data points. */ -#define IDLE_TIMEOUT_WHILE_LEARNING (10*60) - /** Find each circuit that has been unused for too long, or dirty * for too long and has no streams on it: mark it for close. */ @@ -1397,21 +1392,15 @@ circuit_expire_old_circuits_clientside(void) struct timeval cutoff, now; tor_gettimeofday(&now); - cutoff = now; last_expired_clientside_circuits = now.tv_sec; - if (! circuit_build_times_disabled(get_options()) && - circuit_build_times_needs_circuits(get_circuit_build_times())) { - /* Circuits should be shorter lived if we need more of them - * for learning a good build timeout */ - cutoff.tv_sec -= IDLE_TIMEOUT_WHILE_LEARNING; - } else { - cutoff.tv_sec -= get_options()->CircuitIdleTimeout; - } - SMARTLIST_FOREACH_BEGIN(circuit_get_global_list(), circuit_t *, circ) { if (circ->marked_for_close || !CIRCUIT_IS_ORIGIN(circ)) continue; + + cutoff = now; + cutoff.tv_sec -= TO_ORIGIN_CIRCUIT(circ)->circuit_idle_timeout; + /* If the circuit has been dirty for too long, and there are no streams * on it, mark it for close. */ @@ -1437,8 +1426,10 @@ circuit_expire_old_circuits_clientside(void) (circ->purpose >= CIRCUIT_PURPOSE_C_INTRODUCING && circ->purpose <= CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED) || circ->purpose == CIRCUIT_PURPOSE_S_CONNECT_REND) { - log_debug(LD_CIRC, - "Closing circuit that has been unused for %ld msec.", + log_info(LD_CIRC, + "Closing circuit "U64_FORMAT + " that has been unused for %ld msec.", + U64_PRINTF_ARG(TO_ORIGIN_CIRCUIT(circ)->global_identifier), tv_mdiff(&circ->timestamp_began, &now)); circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED); } else if (!TO_ORIGIN_CIRCUIT(circ)->is_ancient) { diff --git a/src/or/command.c b/src/or/command.c index c91a967fd4..c667cbbe52 100644 --- a/src/or/command.c +++ b/src/or/command.c @@ -326,10 +326,19 @@ command_process_create_cell(cell_t *cell, channel_t *chan) return; } + if (connection_or_digest_is_known_relay(chan->identity_digest)) { + rep_hist_note_circuit_handshake_requested(create_cell->handshake_type); + // Needed for chutney: Sometimes relays aren't in the consensus yet, and + // get marked as clients. This resets their channels once they appear. + // Probably useful for normal operation wrt relay flapping, too. + chan->is_client = 0; + } else { + channel_mark_client(chan); + } + if (create_cell->handshake_type != ONION_HANDSHAKE_TYPE_FAST) { /* hand it off to the cpuworkers, and then return. */ - if (connection_or_digest_is_known_relay(chan->identity_digest)) - rep_hist_note_circuit_handshake_requested(create_cell->handshake_type); + if (assign_onionskin_to_cpuworker(circ, create_cell) < 0) { log_debug(LD_GENERAL,"Failed to hand off onionskin. Closing."); circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_RESOURCELIMIT); diff --git a/src/or/config.c b/src/or/config.c index 201cca7941..92808682e8 100644 --- a/src/or/config.c +++ b/src/or/config.c @@ -243,9 +243,11 @@ static config_var_t option_vars_[] = { V(BridgeRecordUsageByCountry, BOOL, "1"), V(BridgeRelay, BOOL, "0"), V(CellStatistics, BOOL, "0"), + V(PaddingStatistics, BOOL, "1"), V(LearnCircuitBuildTimeout, BOOL, "1"), V(CircuitBuildTimeout, INTERVAL, "0"), - V(CircuitIdleTimeout, INTERVAL, "1 hour"), + OBSOLETE("CircuitIdleTimeout"), + V(CircuitsAvailableTimeout, INTERVAL, "0"), V(CircuitStreamTimeout, INTERVAL, "0"), V(CircuitPriorityHalflife, DOUBLE, "-100.0"), /*negative:'Use default'*/ V(ClientDNSRejectInternalAddresses, BOOL,"1"), @@ -402,7 +404,7 @@ static config_var_t option_vars_[] = { V(NATDListenAddress, LINELIST, NULL), VPORT(NATDPort), V(Nickname, STRING, NULL), - V(PredictedPortsRelevanceTime, INTERVAL, "1 hour"), + OBSOLETE("PredictedPortsRelevanceTime"), V(WarnUnsafeSocks, BOOL, "1"), VAR("NodeFamily", LINELIST, NodeFamilies, NULL), V(NumCPUs, UINT, "0"), @@ -459,6 +461,8 @@ static config_var_t option_vars_[] = { V(RecommendedClientVersions, LINELIST, NULL), V(RecommendedServerVersions, LINELIST, NULL), V(RecommendedPackages, LINELIST, NULL), + V(ReducedConnectionPadding, BOOL, "0"), + V(ConnectionPadding, AUTOBOOL, "auto"), V(RefuseUnknownExits, AUTOBOOL, "auto"), V(RejectPlaintextPorts, CSV, ""), V(RelayBandwidthBurst, MEMUNIT, "0"), @@ -2819,10 +2823,10 @@ compute_publishserverdescriptor(or_options_t *options) #define MIN_REND_POST_PERIOD (10*60) #define MIN_REND_POST_PERIOD_TESTING (5) -/** Highest allowable value for PredictedPortsRelevanceTime; if this is - * too high, our selection of exits will decrease for an extended - * period of time to an uncomfortable level .*/ -#define MAX_PREDICTED_CIRCS_RELEVANCE (60*60) +/** Higest allowable value for CircuitsAvailableTimeout. + * If this is too large, client connections will stay open for too long, + * incurring extra padding overhead. */ +#define MAX_CIRCS_AVAILABLE_TIME (24*60*60) /** Highest allowable value for RendPostPeriod. */ #define MAX_DIR_PERIOD ((7*24*60*60)/2) @@ -3439,6 +3443,14 @@ options_validate(or_options_t *old_options, or_options_t *options, options->DirPort_set = 0; } + if (server_mode(options) && options->ConnectionPadding != -1) { + REJECT("Relays must use 'auto' for the ConnectionPadding setting."); + } + + if (server_mode(options) && options->ReducedConnectionPadding != 0) { + REJECT("Relays cannot set ReducedConnectionPadding. "); + } + if (options->MinUptimeHidServDirectoryV2 < 0) { log_warn(LD_CONFIG, "MinUptimeHidServDirectoryV2 option must be at " "least 0 seconds. Changing to 0."); @@ -3460,17 +3472,17 @@ options_validate(or_options_t *old_options, or_options_t *options, options->RendPostPeriod = MAX_DIR_PERIOD; } - if (options->PredictedPortsRelevanceTime > - MAX_PREDICTED_CIRCS_RELEVANCE) { - log_warn(LD_CONFIG, "PredictedPortsRelevanceTime is too large; " - "clipping to %ds.", MAX_PREDICTED_CIRCS_RELEVANCE); - options->PredictedPortsRelevanceTime = MAX_PREDICTED_CIRCS_RELEVANCE; - } - /* Check the Single Onion Service options */ if (options_validate_single_onion(options, msg) < 0) return -1; + if (options->CircuitsAvailableTimeout > MAX_CIRCS_AVAILABLE_TIME) { + // options_t is immutable for new code (the above code is older), + // so just make the user fix the value themselves rather than + // silently keep a shadow value lower than what they asked for. + REJECT("CircuitsAvailableTimeout is too large. Max is 24 hours."); + } + #ifdef ENABLE_TOR2WEB_MODE if (options->Tor2webMode && options->UseEntryGuards) { /* tor2web mode clients do not (and should not) use entry guards diff --git a/src/or/connection_or.c b/src/or/connection_or.c index 61da43e119..280f8f70ad 100644 --- a/src/or/connection_or.c +++ b/src/or/connection_or.c @@ -55,6 +55,7 @@ #include "ext_orport.h" #include "scheduler.h" #include "torcert.h" +#include "channelpadding.h" static int connection_tls_finish_handshake(or_connection_t *conn); static int connection_or_launch_v3_or_handshake(or_connection_t *conn); @@ -814,24 +815,6 @@ connection_or_update_token_buckets(smartlist_t *conns, }); } -/** How long do we wait before killing non-canonical OR connections with no - * circuits? In Tor versions up to 0.2.1.25 and 0.2.2.12-alpha, we waited 15 - * minutes before cancelling these connections, which caused fast relays to - * accrue many many idle connections. Hopefully 3-4.5 minutes is low enough - * that it kills most idle connections, without being so low that we cause - * clients to bounce on and off. - * - * For canonical connections, the limit is higher, at 15-22.5 minutes. - * - * For each OR connection, we randomly add up to 50% extra to its idle_timeout - * field, to avoid exposing when exactly the last circuit closed. Since we're - * storing idle_timeout in a uint16_t, don't let these values get higher than - * 12 hours or so without revising connection_or_set_canonical and/or expanding - * idle_timeout. - */ -#define IDLE_OR_CONN_TIMEOUT_NONCANONICAL 180 -#define IDLE_OR_CONN_TIMEOUT_CANONICAL 900 - /* Mark <b>or_conn</b> as canonical if <b>is_canonical</b> is set, and * non-canonical otherwise. Adjust idle_timeout accordingly. */ @@ -839,9 +822,6 @@ void connection_or_set_canonical(or_connection_t *or_conn, int is_canonical) { - const unsigned int timeout_base = is_canonical ? - IDLE_OR_CONN_TIMEOUT_CANONICAL : IDLE_OR_CONN_TIMEOUT_NONCANONICAL; - if (bool_eq(is_canonical, or_conn->is_canonical) && or_conn->idle_timeout != 0) { /* Don't recalculate an existing idle_timeout unless the canonical @@ -850,7 +830,14 @@ connection_or_set_canonical(or_connection_t *or_conn, } or_conn->is_canonical = !! is_canonical; /* force to a 1-bit boolean */ - or_conn->idle_timeout = timeout_base + crypto_rand_int(timeout_base / 2); + or_conn->idle_timeout = channelpadding_get_channel_idle_timeout( + TLS_CHAN_TO_BASE(or_conn->chan), is_canonical); + + log_info(LD_CIRC, + "Channel " U64_FORMAT " chose an idle timeout of %d.", + or_conn->chan ? + U64_PRINTF_ARG(TLS_CHAN_TO_BASE(or_conn->chan)->global_identifier):0, + or_conn->idle_timeout); } /** If we don't necessarily know the router we're connecting to, but we @@ -1053,10 +1040,8 @@ connection_or_group_set_badness_(smartlist_t *group, int force) } if (!best || - channel_is_better(now, - TLS_CHAN_TO_BASE(or_conn->chan), - TLS_CHAN_TO_BASE(best->chan), - 0)) { + channel_is_better(TLS_CHAN_TO_BASE(or_conn->chan), + TLS_CHAN_TO_BASE(best->chan))) { best = or_conn; } } SMARTLIST_FOREACH_END(or_conn); @@ -1084,11 +1069,9 @@ connection_or_group_set_badness_(smartlist_t *group, int force) or_conn->base_.state != OR_CONN_STATE_OPEN) continue; if (or_conn != best && - channel_is_better(now, - TLS_CHAN_TO_BASE(best->chan), - TLS_CHAN_TO_BASE(or_conn->chan), 1)) { - /* This isn't the best conn, _and_ the best conn is better than it, - even when we're being forgiving. */ + channel_is_better(TLS_CHAN_TO_BASE(best->chan), + TLS_CHAN_TO_BASE(or_conn->chan))) { + /* This isn't the best conn, _and_ the best conn is better than it */ if (best->is_canonical) { log_info(LD_OR, "Marking OR conn to %s:%d as unsuitable for new circuits: " @@ -1983,12 +1966,23 @@ connection_or_write_cell_to_buf(const cell_t *cell, or_connection_t *conn) cell_pack(&networkcell, cell, conn->wide_circ_ids); + rep_hist_padding_count_write(PADDING_TYPE_TOTAL); + if (cell->command == CELL_PADDING) + rep_hist_padding_count_write(PADDING_TYPE_CELL); + connection_write_to_buf(networkcell.body, cell_network_size, TO_CONN(conn)); /* Touch the channel's active timestamp if there is one */ - if (conn->chan) + if (conn->chan) { channel_timestamp_active(TLS_CHAN_TO_BASE(conn->chan)); + if (TLS_CHAN_TO_BASE(conn->chan)->currently_padding) { + rep_hist_padding_count_write(PADDING_TYPE_ENABLED_TOTAL); + if (cell->command == CELL_PADDING) + rep_hist_padding_count_write(PADDING_TYPE_ENABLED_CELL); + } + } + if (conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3) or_handshake_state_record_cell(conn, conn->handshake_state, cell, 0); } @@ -2094,7 +2088,7 @@ connection_or_process_cells_from_inbuf(or_connection_t *conn) } /** Array of recognized link protocol versions. */ -static const uint16_t or_protocol_versions[] = { 1, 2, 3, 4 }; +static const uint16_t or_protocol_versions[] = { 1, 2, 3, 4, 5 }; /** Number of versions in <b>or_protocol_versions</b>. */ static const int n_or_protocol_versions = (int)( sizeof(or_protocol_versions)/sizeof(uint16_t) ); diff --git a/src/or/connection_or.h b/src/or/connection_or.h index 40008426e9..4261658932 100644 --- a/src/or/connection_or.h +++ b/src/or/connection_or.h @@ -109,6 +109,8 @@ void var_cell_free(var_cell_t *cell); /* DOCDOC */ #define MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS 4 +#define MIN_LINK_PROTO_FOR_CHANNEL_PADDING 5 +#define MAX_LINK_PROTO MIN_LINK_PROTO_FOR_CHANNEL_PADDING void connection_or_group_set_badness_(smartlist_t *group, int force); diff --git a/src/or/include.am b/src/or/include.am index 4c24dd23b3..7b031f737b 100644 --- a/src/or/include.am +++ b/src/or/include.am @@ -22,6 +22,7 @@ LIBTOR_A_SOURCES = \ src/or/bridges.c \ src/or/buffers.c \ src/or/channel.c \ + src/or/channelpadding.c \ src/or/channeltls.c \ src/or/circpathbias.c \ src/or/circuitbuild.c \ @@ -144,6 +145,7 @@ ORHEADERS = \ src/or/bridges.h \ src/or/buffers.h \ src/or/channel.h \ + src/or/channelpadding.h \ src/or/channeltls.h \ src/or/circpathbias.h \ src/or/circuitbuild.h \ diff --git a/src/or/main.c b/src/or/main.c index 0da43dc232..fe63ddb091 100644 --- a/src/or/main.c +++ b/src/or/main.c @@ -54,6 +54,7 @@ #include "buffers.h" #include "channel.h" #include "channeltls.h" +#include "channelpadding.h" #include "circuitbuild.h" #include "circuitlist.h" #include "circuituse.h" @@ -177,7 +178,7 @@ static int signewnym_is_pending = 0; static unsigned newnym_epoch = 0; /** Smartlist of all open connections. */ -static smartlist_t *connection_array = NULL; +STATIC smartlist_t *connection_array = NULL; /** List of connections that have been marked for close and need to be freed * and removed from connection_array. */ static smartlist_t *closeable_connection_lst = NULL; @@ -1096,8 +1097,9 @@ run_connection_housekeeping(int i, time_t now) } else if (!have_any_circuits && now - or_conn->idle_timeout >= chan->timestamp_last_had_circuits) { - log_info(LD_OR,"Expiring non-used OR connection to fd %d (%s:%d) " - "[no circuits for %d; timeout %d; %scanonical].", + log_info(LD_OR,"Expiring non-used OR connection "U64_FORMAT" to fd %d " + "(%s:%d) [no circuits for %d; timeout %d; %scanonical].", + U64_PRINTF_ARG(chan->global_identifier), (int)conn->s, conn->address, conn->port, (int)(now - chan->timestamp_last_had_circuits), or_conn->idle_timeout, @@ -1120,6 +1122,8 @@ run_connection_housekeeping(int i, time_t now) memset(&cell,0,sizeof(cell_t)); cell.command = CELL_PADDING; connection_or_write_cell_to_buf(&cell, or_conn); + } else { + channelpadding_decide_to_pad_channel(chan); } } @@ -1187,6 +1191,8 @@ CALLBACK(write_bridge_ns); CALLBACK(check_fw_helper_app); CALLBACK(heartbeat); CALLBACK(clean_consdiffmgr); +CALLBACK(reset_padding_counts); +CALLBACK(check_canonical_channels); #undef CALLBACK @@ -1220,6 +1226,8 @@ static periodic_event_item_t periodic_events[] = { CALLBACK(check_fw_helper_app), CALLBACK(heartbeat), CALLBACK(clean_consdiffmgr), + CALLBACK(reset_padding_counts), + CALLBACK(check_canonical_channels), END_OF_PERIODIC_EVENTS }; #undef CALLBACK @@ -1756,6 +1764,28 @@ write_stats_file_callback(time_t now, const or_options_t *options) return safe_timer_diff(now, next_time_to_write_stats_files); } +#define CHANNEL_CHECK_INTERVAL (60*60) +static int +check_canonical_channels_callback(time_t now, const or_options_t *options) +{ + (void)now; + if (public_server_mode(options)) + channel_check_for_duplicates(); + + return CHANNEL_CHECK_INTERVAL; +} + +static int +reset_padding_counts_callback(time_t now, const or_options_t *options) +{ + if (options->PaddingStatistics) { + rep_hist_prep_published_padding_counts(now); + } + + rep_hist_reset_padding_counts(); + return REPHIST_CELL_PADDING_COUNTS_INTERVAL; +} + /** * Periodic callback: Write bridge statistics to disk if appropriate. */ @@ -2383,6 +2413,8 @@ do_main_loop(void) } handle_signals(1); + monotime_init(); + timers_initialize(); /* load the private keys, if we're supposed to have them, and set up the * TLS context. */ @@ -3053,6 +3085,13 @@ tor_init(int argc, char *argv[]) /* The options are now initialised */ const or_options_t *options = get_options(); + /* Initialize channelpadding parameters to defaults until we get + * a consensus */ + channelpadding_new_consensus_params(NULL); + + /* Initialize predicted ports list after loading options */ + predicted_ports_init(); + #ifndef _WIN32 if (geteuid()==0) log_warn(LD_GENERAL,"You are running Tor as root. You don't need to, " @@ -3250,6 +3289,9 @@ tor_cleanup(void) rep_hist_record_mtbf_data(now, 0); keypin_close_journal(); } + + timers_shutdown(); + #ifdef USE_DMALLOC dmalloc_log_stats(); #endif diff --git a/src/or/networkstatus.c b/src/or/networkstatus.c index 1b21dd7b45..ac5c5c526c 100644 --- a/src/or/networkstatus.c +++ b/src/or/networkstatus.c @@ -64,6 +64,7 @@ #include "shared_random.h" #include "transports.h" #include "torcert.h" +#include "channelpadding.h" /** Map from lowercase nickname to identity digest of named server, if any. */ static strmap_t *named_server_map = NULL; @@ -73,11 +74,11 @@ static strmap_t *unnamed_server_map = NULL; /** Most recently received and validated v3 "ns"-flavored consensus network * status. */ -static networkstatus_t *current_ns_consensus = NULL; +STATIC networkstatus_t *current_ns_consensus = NULL; /** Most recently received and validated v3 "microdec"-flavored consensus * network status. */ -static networkstatus_t *current_md_consensus = NULL; +STATIC networkstatus_t *current_md_consensus = NULL; /** A v3 consensus networkstatus that we've received, but which we don't * have enough certificates to be happy about. */ @@ -1988,6 +1989,7 @@ networkstatus_set_current_consensus(const char *consensus, circuit_build_times_new_consensus_params( get_circuit_build_times_mutable(), c); + channelpadding_new_consensus_params(c); } /* Reset the failure count only if this consensus is actually valid. */ diff --git a/src/or/or.h b/src/or/or.h index 423f66cdd5..4d6ac93548 100644 --- a/src/or/or.h +++ b/src/or/or.h @@ -896,6 +896,7 @@ typedef enum { #define CELL_RELAY_EARLY 9 #define CELL_CREATE2 10 #define CELL_CREATED2 11 +#define CELL_PADDING_NEGOTIATE 12 #define CELL_VPADDING 128 #define CELL_CERTS 129 @@ -3331,6 +3332,13 @@ typedef struct origin_circuit_t { * adjust_exit_policy_from_exitpolicy_failure. */ smartlist_t *prepend_policy; + + /** How long do we wait before closing this circuit if it remains + * completely idle after it was built, in seconds? This value + * is randomized on a per-circuit basis from CircuitsAvailableTimoeut + * to 2*CircuitsAvailableTimoeut. */ + int circuit_idle_timeout; + } origin_circuit_t; struct onion_queue_t; @@ -3759,6 +3767,15 @@ typedef struct { int AvoidDiskWrites; /**< Boolean: should we never cache things to disk? * Not used yet. */ int ClientOnly; /**< Boolean: should we never evolve into a server role? */ + + int ReducedConnectionPadding; /**< Boolean: Should we try to keep connections + open shorter and pad them less against + connection-level traffic analysis? */ + /** Autobool: if auto, then connection padding will be negotiated by client + * and server. If 0, it will be fully disabled. If 1, the client will still + * pad to the server regardless of server support. */ + int ConnectionPadding; + /** To what authority types do we publish our descriptor? Choices are * "v1", "v2", "v3", "bridge", or "". */ smartlist_t *PublishServerDescriptor; @@ -3875,6 +3892,8 @@ typedef struct { * adaptive algorithm learns a new value. */ int CircuitIdleTimeout; /**< Cull open clean circuits that were born * at least this many seconds ago. */ + int CircuitsAvailableTimeout; /**< Try to have an open circuit for at + least this long after last activity */ int CircuitStreamTimeout; /**< If non-zero, detach streams from circuits * and try a new circuit if the stream has been * waiting for this many seconds. If zero, use @@ -4166,6 +4185,9 @@ typedef struct { /** If true, the user wants us to collect cell statistics. */ int CellStatistics; + /** If true, the user wants us to collect padding statistics. */ + int PaddingStatistics; + /** If true, the user wants us to collect statistics as entry node. */ int EntryStatistics; @@ -4816,7 +4838,7 @@ typedef uint32_t build_time_t; double circuit_build_times_quantile_cutoff(void); /** How often in seconds should we build a test circuit */ -#define CBT_DEFAULT_TEST_FREQUENCY 60 +#define CBT_DEFAULT_TEST_FREQUENCY 10 #define CBT_MIN_TEST_FREQUENCY 1 #define CBT_MAX_TEST_FREQUENCY INT32_MAX diff --git a/src/or/relay.c b/src/or/relay.c index 1842012ed7..7082002f84 100644 --- a/src/or/relay.c +++ b/src/or/relay.c @@ -75,6 +75,7 @@ #include "routerlist.h" #include "routerparse.h" #include "scheduler.h" +#include "rephist.h" static edge_connection_t *relay_lookup_conn(circuit_t *circ, cell_t *cell, cell_direction_t cell_direction, @@ -197,6 +198,82 @@ relay_crypt_one_payload(crypto_cipher_t *cipher, uint8_t *in, return 0; } +/** + * Update channel usage state based on the type of relay cell and + * circuit properties. + * + * This is needed to determine if a client channel is being + * used for application traffic, and if a relay channel is being + * used for multihop circuits and application traffic. The decision + * to pad in channelpadding.c depends upon this info (as well as + * consensus parameters) to decide what channels to pad. + */ +static void +circuit_update_channel_usage(circuit_t *circ, cell_t *cell) +{ + if (CIRCUIT_IS_ORIGIN(circ)) { + /* + * The client state was first set much earlier in + * circuit_send_next_onion_skin(), so we can start padding as early as + * possible. + * + * However, if padding turns out to be expensive, we may want to not do + * it until actual application traffic starts flowing (which is controlled + * via consensus param nf_pad_before_usage). + * + * So: If we're an origin circuit and we've created a full length circuit, + * then any CELL_RELAY cell means application data. Increase the usage + * state of the channel to indicate this. + * + * We want to wait for CELL_RELAY specifically here, so we know that + * the channel was definitely being used for data and not for extends. + * By default, we pad as soon as a channel has been used for *any* + * circuits, so this state is irrelevant to the padding decision in + * the default case. However, if padding turns out to be expensive, + * we would like the ability to avoid padding until we're absolutely + * sure that a channel is used for enough application data to be worth + * padding. + * + * (So it does not matter that CELL_RELAY_EARLY can actually contain + * application data. This is only a load reducing option and that edge + * case does not matter if we're desperately trying to reduce overhead + * anyway. See also consensus parameter nf_pad_before_usage). + */ + if (BUG(!circ->n_chan)) + return; + + if (circ->n_chan->channel_usage == CHANNEL_USED_FOR_FULL_CIRCS && + cell->command == CELL_RELAY) { + circ->n_chan->channel_usage = CHANNEL_USED_FOR_USER_TRAFFIC; + } + } else { + /* If we're a relay circuit, the question is more complicated. Basically: + * we only want to pad connections that carry multihop (anonymous) + * circuits. + * + * We assume we're more than one hop if either the previous hop + * is not a client, or if the previous hop is a client and there's + * a next hop. Then, circuit traffic starts at RELAY_EARLY, and + * user application traffic starts when we see RELAY cells. + */ + or_circuit_t *or_circ = TO_OR_CIRCUIT(circ); + + if (BUG(!or_circ->p_chan)) + return; + + if (!channel_is_client(or_circ->p_chan) || + (channel_is_client(or_circ->p_chan) && circ->n_chan)) { + if (cell->command == CELL_RELAY_EARLY) { + if (or_circ->p_chan->channel_usage < CHANNEL_USED_FOR_FULL_CIRCS) { + or_circ->p_chan->channel_usage = CHANNEL_USED_FOR_FULL_CIRCS; + } + } else if (cell->command == CELL_RELAY) { + or_circ->p_chan->channel_usage = CHANNEL_USED_FOR_USER_TRAFFIC; + } + } + } +} + /** Receive a relay cell: * - Crypt it (encrypt if headed toward the origin or if we <b>are</b> the * origin; decrypt if we're headed toward the exit). @@ -231,6 +308,8 @@ circuit_receive_relay_cell(cell_t *cell, circuit_t *circ, return -END_CIRC_REASON_INTERNAL; } + circuit_update_channel_usage(circ, cell); + if (recognized) { edge_connection_t *conn = NULL; @@ -639,6 +718,9 @@ relay_send_command_from_edge_,(streamid_t stream_id, circuit_t *circ, log_debug(LD_OR,"delivering %d cell %s.", relay_command, cell_direction == CELL_DIRECTION_OUT ? "forward" : "backward"); + if (relay_command == RELAY_COMMAND_DROP) + rep_hist_padding_count_write(PADDING_TYPE_DROP); + /* If we are sending an END cell and this circuit is used for a tunneled * directory request, advance its state. */ if (relay_command == RELAY_COMMAND_END && circ->dirreq_id) @@ -1530,6 +1612,7 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ, switch (rh.command) { case RELAY_COMMAND_DROP: + rep_hist_padding_count_read(PADDING_TYPE_DROP); // log_info(domain,"Got a relay-level padding cell. Dropping."); return 0; case RELAY_COMMAND_BEGIN: diff --git a/src/or/rephist.c b/src/or/rephist.c index 231130f13c..96087f92e7 100644 --- a/src/or/rephist.c +++ b/src/or/rephist.c @@ -84,9 +84,13 @@ #include "router.h" #include "routerlist.h" #include "ht.h" +#include "channelpadding.h" + +#include "channelpadding.h" +#include "connection_or.h" static void bw_arrays_init(void); -static void predicted_ports_init(void); +static void predicted_ports_alloc(void); /** Total number of bytes currently allocated in fields used by rephist.c. */ uint64_t rephist_total_alloc=0; @@ -165,6 +169,44 @@ typedef struct or_history_t { digestmap_t *link_history_map; } or_history_t; +/** + * This structure holds accounting needed to calculate the padding overhead. + */ +typedef struct padding_counts_t { + /** Total number of cells we have received, including padding */ + uint64_t read_cell_count; + /** Total number of cells we have sent, including padding */ + uint64_t write_cell_count; + /** Total number of CELL_PADDING cells we have received */ + uint64_t read_pad_cell_count; + /** Total number of CELL_PADDING cells we have sent */ + uint64_t write_pad_cell_count; + /** Total number of read cells on padding-enabled conns */ + uint64_t enabled_read_cell_count; + /** Total number of sent cells on padding-enabled conns */ + uint64_t enabled_write_cell_count; + /** Total number of read CELL_PADDING cells on padding-enabled cons */ + uint64_t enabled_read_pad_cell_count; + /** Total number of sent CELL_PADDING cells on padding-enabled cons */ + uint64_t enabled_write_pad_cell_count; + /** Total number of RELAY_DROP cells we have received */ + uint64_t read_drop_cell_count; + /** Total number of RELAY_DROP cells we have sent */ + uint64_t write_drop_cell_count; + /** The maximum number of padding timers we've seen in 24 hours */ + uint64_t maximum_chanpad_timers; + /** When did we first copy padding_current into padding_published? */ + char first_published_at[ISO_TIME_LEN+1]; +} padding_counts_t; + +/** Holds the current values of our padding statistics. + * It is not published until it is transferred to padding_published. */ +static padding_counts_t padding_current; + +/** Remains fixed for a 24 hour period, and then is replaced + * by a redacted copy of padding_current */ +static padding_counts_t padding_published; + /** When did we last multiply all routers' weighted_run_length and * total_run_weights by STABILITY_ALPHA? */ static time_t stability_last_downrated = 0; @@ -264,7 +306,7 @@ rep_hist_init(void) { history_map = digestmap_new(); bw_arrays_init(); - predicted_ports_init(); + predicted_ports_alloc(); } /** Helper: note that we are no longer connected to the router with history @@ -1758,6 +1800,36 @@ typedef struct predicted_port_t { /** A list of port numbers that have been used recently. */ static smartlist_t *predicted_ports_list=NULL; +/** How long do we keep predicting circuits? */ +static int prediction_timeout=0; +/** When was the last time we added a prediction entry (HS or port) */ +static time_t last_prediction_add_time=0; + +/** + * How much time left until we stop predicting circuits? + */ +int +predicted_ports_prediction_time_remaining(time_t now) +{ + time_t idle_delta = now - last_prediction_add_time; + + /* Protect against overflow of return value. This can happen if the clock + * jumps backwards in time. Update the last prediction time (aka last + * active time) to prevent it. This update is preferable to using monotonic + * time because it prevents clock jumps into the past from simply causing + * very long idle timeouts while the monotonic time stands still. */ + if (last_prediction_add_time > now) { + last_prediction_add_time = now; + idle_delta = 0; + } + + /* Protect against underflow of the return value. This can happen for very + * large periods of inactivity/system sleep. */ + if (idle_delta > prediction_timeout) + return 0; + + return prediction_timeout - idle_delta; +} /** We just got an application request for a connection with * port <b>port</b>. Remember it for the future, so we can keep @@ -1767,21 +1839,40 @@ static void add_predicted_port(time_t now, uint16_t port) { predicted_port_t *pp = tor_malloc(sizeof(predicted_port_t)); + + // If the list is empty, re-randomize predicted ports lifetime + if (!any_predicted_circuits(now)) { + prediction_timeout = channelpadding_get_circuits_available_timeout(); + } + + last_prediction_add_time = now; + + log_info(LD_CIRC, + "New port prediction added. Will continue predictive circ building " + "for %d more seconds.", + predicted_ports_prediction_time_remaining(now)); + pp->port = port; pp->time = now; rephist_total_alloc += sizeof(*pp); smartlist_add(predicted_ports_list, pp); } -/** Initialize whatever memory and structs are needed for predicting +/** + * Allocate whatever memory and structs are needed for predicting * which ports will be used. Also seed it with port 80, so we'll build * circuits on start-up. */ static void -predicted_ports_init(void) +predicted_ports_alloc(void) { predicted_ports_list = smartlist_new(); - add_predicted_port(time(NULL), 80); /* add one to kickstart us */ +} + +void +predicted_ports_init(void) +{ + add_predicted_port(time(NULL), 443); // Add a port to get us started } /** Free whatever memory is needed for predicting which ports will @@ -1812,6 +1903,12 @@ rep_hist_note_used_port(time_t now, uint16_t port) SMARTLIST_FOREACH_BEGIN(predicted_ports_list, predicted_port_t *, pp) { if (pp->port == port) { pp->time = now; + + last_prediction_add_time = now; + log_info(LD_CIRC, + "New port prediction added. Will continue predictive circ " + "building for %d more seconds.", + predicted_ports_prediction_time_remaining(now)); return; } } SMARTLIST_FOREACH_END(pp); @@ -1828,7 +1925,8 @@ rep_hist_get_predicted_ports(time_t now) int predicted_circs_relevance_time; smartlist_t *out = smartlist_new(); tor_assert(predicted_ports_list); - predicted_circs_relevance_time = get_options()->PredictedPortsRelevanceTime; + + predicted_circs_relevance_time = prediction_timeout; /* clean out obsolete entries */ SMARTLIST_FOREACH_BEGIN(predicted_ports_list, predicted_port_t *, pp) { @@ -1888,6 +1986,18 @@ static time_t predicted_internal_capacity_time = 0; void rep_hist_note_used_internal(time_t now, int need_uptime, int need_capacity) { + // If the list is empty, re-randomize predicted ports lifetime + if (!any_predicted_circuits(now)) { + prediction_timeout = channelpadding_get_circuits_available_timeout(); + } + + last_prediction_add_time = now; + + log_info(LD_CIRC, + "New port prediction added. Will continue predictive circ building " + "for %d more seconds.", + predicted_ports_prediction_time_remaining(now)); + predicted_internal_time = now; if (need_uptime) predicted_internal_uptime_time = now; @@ -1901,7 +2011,8 @@ rep_hist_get_predicted_internal(time_t now, int *need_uptime, int *need_capacity) { int predicted_circs_relevance_time; - predicted_circs_relevance_time = get_options()->PredictedPortsRelevanceTime; + + predicted_circs_relevance_time = prediction_timeout; if (!predicted_internal_time) { /* initialize it */ predicted_internal_time = now; @@ -1923,7 +2034,7 @@ int any_predicted_circuits(time_t now) { int predicted_circs_relevance_time; - predicted_circs_relevance_time = get_options()->PredictedPortsRelevanceTime; + predicted_circs_relevance_time = prediction_timeout; return smartlist_len(predicted_ports_list) || predicted_internal_time + predicted_circs_relevance_time >= now; @@ -3210,8 +3321,7 @@ rep_hist_hs_stats_write(time_t now) return start_of_hs_stats_interval + WRITE_STATS_INTERVAL; } -#define MAX_LINK_PROTO_TO_LOG 4 -static uint64_t link_proto_count[MAX_LINK_PROTO_TO_LOG+1][2]; +static uint64_t link_proto_count[MAX_LINK_PROTO+1][2]; /** Note that we negotiated link protocol version <b>link_proto</b>, on * a connection that started here iff <b>started_here</b> is true. @@ -3220,7 +3330,7 @@ void rep_hist_note_negotiated_link_proto(unsigned link_proto, int started_here) { started_here = !!started_here; /* force to 0 or 1 */ - if (link_proto > MAX_LINK_PROTO_TO_LOG) { + if (link_proto > MAX_LINK_PROTO) { log_warn(LD_BUG, "Can't log link protocol %u", link_proto); return; } @@ -3228,6 +3338,165 @@ rep_hist_note_negotiated_link_proto(unsigned link_proto, int started_here) link_proto_count[link_proto][started_here]++; } +/** + * Update the maximum count of total pending channel padding timers + * in this period. + */ +void +rep_hist_padding_count_timers(uint64_t num_timers) +{ + if (num_timers > padding_current.maximum_chanpad_timers) { + padding_current.maximum_chanpad_timers = num_timers; + } +} + +/** + * Count a cell that we sent for padding overhead statistics. + * + * RELAY_COMMAND_DROP and CELL_PADDING are accounted separately. Both should be + * counted for PADDING_TYPE_TOTAL. + */ +void +rep_hist_padding_count_write(padding_type_t type) +{ + switch (type) { + case PADDING_TYPE_DROP: + padding_current.write_drop_cell_count++; + break; + case PADDING_TYPE_CELL: + padding_current.write_pad_cell_count++; + break; + case PADDING_TYPE_TOTAL: + padding_current.write_cell_count++; + break; + case PADDING_TYPE_ENABLED_TOTAL: + padding_current.enabled_write_cell_count++; + break; + case PADDING_TYPE_ENABLED_CELL: + padding_current.enabled_write_pad_cell_count++; + break; + } +} + +/** + * Count a cell that we've received for padding overhead statistics. + * + * RELAY_COMMAND_DROP and CELL_PADDING are accounted separately. Both should be + * counted for PADDING_TYPE_TOTAL. + */ +void +rep_hist_padding_count_read(padding_type_t type) +{ + switch (type) { + case PADDING_TYPE_DROP: + padding_current.read_drop_cell_count++; + break; + case PADDING_TYPE_CELL: + padding_current.read_pad_cell_count++; + break; + case PADDING_TYPE_TOTAL: + padding_current.read_cell_count++; + break; + case PADDING_TYPE_ENABLED_TOTAL: + padding_current.enabled_read_cell_count++; + break; + case PADDING_TYPE_ENABLED_CELL: + padding_current.enabled_read_pad_cell_count++; + break; + } +} + +/** + * Reset our current padding statistics. Called once every 24 hours. + */ +void +rep_hist_reset_padding_counts(void) +{ + memset(&padding_current, 0, sizeof(padding_current)); +} + +/** + * Copy our current cell counts into a structure for listing in our + * extra-info descriptor. Also perform appropriate rounding and redaction. + * + * This function is called once every 24 hours. + */ +#define MIN_CELL_COUNTS_TO_PUBLISH 1 +#define ROUND_CELL_COUNTS_TO 10000 +void +rep_hist_prep_published_padding_counts(time_t now) +{ + memcpy(&padding_published, &padding_current, sizeof(padding_published)); + + if (padding_published.read_cell_count < MIN_CELL_COUNTS_TO_PUBLISH || + padding_published.write_cell_count < MIN_CELL_COUNTS_TO_PUBLISH) { + memset(&padding_published, 0, sizeof(padding_published)); + return; + } + + format_iso_time(padding_published.first_published_at, now); +#define ROUND_AND_SET_COUNT(x) (x) = round_uint64_to_next_multiple_of((x), \ + ROUND_CELL_COUNTS_TO) + ROUND_AND_SET_COUNT(padding_published.read_pad_cell_count); + ROUND_AND_SET_COUNT(padding_published.write_pad_cell_count); + ROUND_AND_SET_COUNT(padding_published.read_drop_cell_count); + ROUND_AND_SET_COUNT(padding_published.write_drop_cell_count); + ROUND_AND_SET_COUNT(padding_published.write_cell_count); + ROUND_AND_SET_COUNT(padding_published.read_cell_count); + ROUND_AND_SET_COUNT(padding_published.enabled_read_cell_count); + ROUND_AND_SET_COUNT(padding_published.enabled_read_pad_cell_count); + ROUND_AND_SET_COUNT(padding_published.enabled_write_cell_count); + ROUND_AND_SET_COUNT(padding_published.enabled_write_pad_cell_count); +#undef ROUND_AND_SET_COUNT +} + +/** + * Returns an allocated string for extra-info documents for publishing + * padding statistics from the last 24 hour interval. + */ +char * +rep_hist_get_padding_count_lines(void) +{ + char *result = NULL; + + if (!padding_published.read_cell_count || + !padding_published.write_cell_count) { + return NULL; + } + + tor_asprintf(&result, "padding-counts %s (%d s)" + " bin-size="U64_FORMAT + " write-drop="U64_FORMAT + " write-pad="U64_FORMAT + " write-total="U64_FORMAT + " read-drop="U64_FORMAT + " read-pad="U64_FORMAT + " read-total="U64_FORMAT + " enabled-read-pad="U64_FORMAT + " enabled-read-total="U64_FORMAT + " enabled-write-pad="U64_FORMAT + " enabled-write-total="U64_FORMAT + " max-chanpad-timers="U64_FORMAT + "\n", + padding_published.first_published_at, + REPHIST_CELL_PADDING_COUNTS_INTERVAL, + U64_PRINTF_ARG(ROUND_CELL_COUNTS_TO), + U64_PRINTF_ARG(padding_published.write_drop_cell_count), + U64_PRINTF_ARG(padding_published.write_pad_cell_count), + U64_PRINTF_ARG(padding_published.write_cell_count), + U64_PRINTF_ARG(padding_published.read_drop_cell_count), + U64_PRINTF_ARG(padding_published.read_pad_cell_count), + U64_PRINTF_ARG(padding_published.read_cell_count), + U64_PRINTF_ARG(padding_published.enabled_read_pad_cell_count), + U64_PRINTF_ARG(padding_published.enabled_read_cell_count), + U64_PRINTF_ARG(padding_published.enabled_write_pad_cell_count), + U64_PRINTF_ARG(padding_published.enabled_write_cell_count), + U64_PRINTF_ARG(padding_published.maximum_chanpad_timers) + ); + + return result; +} + /** Log a heartbeat message explaining how many connections of each link * protocol version we have used. */ diff --git a/src/or/rephist.h b/src/or/rephist.h index 6dd88a3544..2b1c2e7ec7 100644 --- a/src/or/rephist.h +++ b/src/or/rephist.h @@ -48,6 +48,7 @@ double rep_hist_get_weighted_fractional_uptime(const char *id, time_t when); long rep_hist_get_weighted_time_known(const char *id, time_t when); int rep_hist_have_measured_enough_stability(void); +void predicted_ports_init(void); void rep_hist_note_used_port(time_t now, uint16_t port); smartlist_t *rep_hist_get_predicted_ports(time_t now); void rep_hist_remove_predicted_ports(const smartlist_t *rmv_ports); @@ -59,6 +60,7 @@ int rep_hist_get_predicted_internal(time_t now, int *need_uptime, int any_predicted_circuits(time_t now); int rep_hist_circbuilding_dormant(time_t now); +int predicted_ports_prediction_time_remaining(time_t now); void note_crypto_pk_op(pk_op_t operation); void dump_pk_ops(int severity); @@ -119,5 +121,30 @@ extern int onion_handshakes_requested[MAX_ONION_HANDSHAKE_TYPE+1]; extern int onion_handshakes_assigned[MAX_ONION_HANDSHAKE_TYPE+1]; #endif +/** + * Represents the type of a cell for padding accounting + */ +typedef enum padding_type_t { + /** A RELAY_DROP cell */ + PADDING_TYPE_DROP, + /** A CELL_PADDING cell */ + PADDING_TYPE_CELL, + /** Total counts of padding and non-padding together */ + PADDING_TYPE_TOTAL, + /** Total cell counts for all padding-enabled channels */ + PADDING_TYPE_ENABLED_TOTAL, + /** CELL_PADDING counts for all padding-enabled channels */ + PADDING_TYPE_ENABLED_CELL +} padding_type_t; + +/** The amount of time over which the padding cell counts were counted */ +#define REPHIST_CELL_PADDING_COUNTS_INTERVAL (24*60*60) +void rep_hist_padding_count_read(padding_type_t type); +void rep_hist_padding_count_write(padding_type_t type); +char *rep_hist_get_padding_count_lines(void); +void rep_hist_reset_padding_counts(void); +void rep_hist_prep_published_padding_counts(time_t now); +void rep_hist_padding_count_timers(uint64_t num_timers); + #endif diff --git a/src/or/router.c b/src/or/router.c index 2336a5d3df..6318f78549 100644 --- a/src/or/router.c +++ b/src/or/router.c @@ -3295,6 +3295,12 @@ extrainfo_dump_to_string(char **s_out, extrainfo_t *extrainfo, } } + if (options->PaddingStatistics) { + contents = rep_hist_get_padding_count_lines(); + if (contents) + smartlist_add(chunks, contents); + } + /* Add information about the pluggable transports we support. */ if (options->ServerTransportPlugin) { char *pluggable_transports = pt_get_extra_info_descriptor_string(); diff --git a/src/test/Makefile.nmake b/src/test/Makefile.nmake index 575198388b..605f1a92c3 100644 --- a/src/test/Makefile.nmake +++ b/src/test/Makefile.nmake @@ -17,6 +17,7 @@ TEST_OBJECTS = test.obj test_addr.obj test_channel.obj test_channeltls.obj \ test_checkdir.obj test_microdesc.obj test_pt.obj test_util.obj \ test_config.obj test_connection.obj \ test_cell_formats.obj test_relay.obj test_replay.obj \ + test_channelpadding.obj \ test_scheduler.obj test_introduce.obj test_hs.obj tinytest.obj tinytest.obj: ..\ext\tinytest.c diff --git a/src/test/include.am b/src/test/include.am index 230a6c8bad..ee14d0651b 100644 --- a/src/test/include.am +++ b/src/test/include.am @@ -78,6 +78,7 @@ src_test_test_SOURCES = \ src/test/test_cell_formats.c \ src/test/test_cell_queue.c \ src/test/test_channel.c \ + src/test/test_channelpadding.c \ src/test/test_channeltls.c \ src/test/test_checkdir.c \ src/test/test_circuitlist.c \ diff --git a/src/test/test.c b/src/test/test.c index 4d2cf1536b..30944d805d 100644 --- a/src/test/test.c +++ b/src/test/test.c @@ -1186,6 +1186,7 @@ struct testgroup_t testgroups[] = { { "cellfmt/", cell_format_tests }, { "cellqueue/", cell_queue_tests }, { "channel/", channel_tests }, + { "channelpadding/", channelpadding_tests }, { "channeltls/", channeltls_tests }, { "checkdir/", checkdir_tests }, { "circuitbuild/", circuitbuild_tests }, diff --git a/src/test/test.h b/src/test/test.h index 3d7d05e771..0ba91fb3f6 100644 --- a/src/test/test.h +++ b/src/test/test.h @@ -181,6 +181,7 @@ extern struct testcase_t buffer_tests[]; extern struct testcase_t cell_format_tests[]; extern struct testcase_t cell_queue_tests[]; extern struct testcase_t channel_tests[]; +extern struct testcase_t channelpadding_tests[]; extern struct testcase_t channeltls_tests[]; extern struct testcase_t checkdir_tests[]; extern struct testcase_t circuitbuild_tests[]; diff --git a/src/test/test_channelpadding.c b/src/test/test_channelpadding.c new file mode 100644 index 0000000000..8ea0f17c7d --- /dev/null +++ b/src/test/test_channelpadding.c @@ -0,0 +1,892 @@ +#define TOR_CHANNEL_INTERNAL_ +#include "or.h" +#include "test.h" +#include "testsupport.h" +#include "connection.h" +#include "connection_or.h" +#include "channel.h" +#include "channeltls.h" +#include "channelpadding.h" +#include "compat_libevent.h" +#include "config.h" +#include <event.h> +#include "compat_time.h" +#include "log_test_helpers.h" + +extern smartlist_t *connection_array; +extern networkstatus_t *current_ns_consensus; +extern networkstatus_t *current_md_consensus; + +int channelpadding_get_netflow_inactive_timeout_ms(channel_t *chan); +int64_t channelpadding_compute_time_until_pad_for_netflow(channel_t *chan); +int channelpadding_send_disable_command(channel_t*); +int channelpadding_find_timerslot(channel_t *chan); + +void test_channelpadding_timers(void *arg); +void test_channelpadding_consensus(void *arg); +void test_channelpadding_negotiation(void *arg); +void test_channelpadding_decide_to_pad_channel(void *arg); + +void dummy_nop_timer(void); + +/* Thing to cast to fake tor_tls_t * to appease assert_connection_ok() */ +static int fake_tortls = 0; /* Bleh... */ + +static int dont_stop_libevent = 0; + +// From test_channel.c +channel_t * new_fake_channel(void); +void free_fake_channel(channel_t*); + +static int +mock_channel_has_queued_writes(channel_t *chan) +{ + (void)chan; + return 0; +} + +static int tried_to_write_cell = 0; + +static channel_t *relay1_relay2; +static channel_t *relay2_relay1; +static channel_t *relay3_client; +static channel_t *client_relay3; + +static int +mock_channel_write_cell_relay2(channel_t *chan, cell_t *cell) +{ + (void)chan; + tried_to_write_cell++; + channel_tls_handle_cell(cell, ((channel_tls_t*)relay1_relay2)->conn); + event_base_loopbreak(tor_libevent_get_base()); + return 0; +} + +static int +mock_channel_write_cell_relay1(channel_t *chan, cell_t *cell) +{ + (void)chan; + tried_to_write_cell++; + channel_tls_handle_cell(cell, ((channel_tls_t*)relay2_relay1)->conn); + event_base_loopbreak(tor_libevent_get_base()); + return 0; +} + +static int +mock_channel_write_cell_relay3(channel_t *chan, cell_t *cell) +{ + (void)chan; + tried_to_write_cell++; + channel_tls_handle_cell(cell, ((channel_tls_t*)client_relay3)->conn); + event_base_loopbreak(tor_libevent_get_base()); + return 0; +} + +static int +mock_channel_write_cell_client(channel_t *chan, cell_t *cell) +{ + (void)chan; + tried_to_write_cell++; + channel_tls_handle_cell(cell, ((channel_tls_t*)relay3_client)->conn); + event_base_loopbreak(tor_libevent_get_base()); + return 0; +} + +static int +mock_channel_write_cell(channel_t *chan, cell_t *cell) +{ + tried_to_write_cell++; + channel_tls_handle_cell(cell, ((channel_tls_t*)chan)->conn); + if (!dont_stop_libevent) + event_base_loopbreak(tor_libevent_get_base()); + return 0; +} + +static void +setup_fake_connection_for_channel(channel_tls_t *chan) +{ + or_connection_t *conn = (or_connection_t*)connection_new(CONN_TYPE_OR, + AF_INET); + + conn->base_.conn_array_index = smartlist_len(connection_array); + smartlist_add(connection_array, conn); + + connection_or_set_canonical(conn, 1); + + conn->chan = chan; + chan->conn = conn; + + conn->base_.magic = OR_CONNECTION_MAGIC; + conn->base_.state = OR_CONN_STATE_OPEN; + conn->base_.type = CONN_TYPE_OR; + conn->base_.socket_family = AF_INET; + conn->base_.address = tor_strdup("<fake>"); + + conn->base_.port = 4242; + + conn->tls = (tor_tls_t *)((void *)(&fake_tortls)); + + conn->link_proto = MIN_LINK_PROTO_FOR_CHANNEL_PADDING; +} + +static channel_tls_t * +new_fake_channeltls(uint8_t id) +{ + channel_tls_t *chan = tor_realloc(new_fake_channel(), sizeof(channel_tls_t)); + chan->base_.magic = TLS_CHAN_MAGIC; + setup_fake_connection_for_channel(chan); + chan->base_.channel_usage = CHANNEL_USED_FOR_FULL_CIRCS; + chan->base_.has_queued_writes = mock_channel_has_queued_writes; + chan->base_.write_cell = mock_channel_write_cell; + chan->base_.padding_enabled = 1; + + chan->base_.identity_digest[0] = id; + channel_register(&chan->base_); + + return chan; +} + +static void +free_fake_channeltls(channel_tls_t *chan) +{ + channel_unregister(&chan->base_); + + tor_free(((channel_tls_t*)chan)->conn->base_.address); + buf_free(((channel_tls_t*)chan)->conn->base_.inbuf); + buf_free(((channel_tls_t*)chan)->conn->base_.outbuf); + tor_free(((channel_tls_t*)chan)->conn); + + timer_free(chan->base_.padding_timer); + channel_handle_free(chan->base_.timer_handle); + channel_handles_clear(&chan->base_); + + free_fake_channel(&chan->base_); + + return; +} + +static void +setup_mock_network(void) +{ + routerstatus_t *relay; + connection_array = smartlist_new(); + + current_md_consensus = current_ns_consensus + = tor_malloc_zero(sizeof(networkstatus_t)); + current_md_consensus->net_params = smartlist_new(); + current_md_consensus->routerstatus_list = smartlist_new(); + channelpadding_new_consensus_params(current_md_consensus); + + relay1_relay2 = (channel_t*)new_fake_channeltls(2); + relay1_relay2->write_cell = mock_channel_write_cell_relay1; + channel_timestamp_active(relay1_relay2); + relay = tor_malloc_zero(sizeof(routerstatus_t)); + relay->identity_digest[0] = 1; + smartlist_add(current_md_consensus->routerstatus_list, relay); + + relay2_relay1 = (channel_t*)new_fake_channeltls(1); + relay2_relay1->write_cell = mock_channel_write_cell_relay2; + channel_timestamp_active(relay2_relay1); + relay = tor_malloc_zero(sizeof(routerstatus_t)); + relay->identity_digest[0] = 2; + smartlist_add(current_md_consensus->routerstatus_list, relay); + + relay3_client = (channel_t*)new_fake_channeltls(0); + relay3_client->write_cell = mock_channel_write_cell_relay3; + relay3_client->is_client = 1; + channel_timestamp_active(relay3_client); + relay = tor_malloc_zero(sizeof(routerstatus_t)); + relay->identity_digest[0] = 3; + smartlist_add(current_md_consensus->routerstatus_list, relay); + + client_relay3 = (channel_t*)new_fake_channeltls(3); + client_relay3->write_cell = mock_channel_write_cell_client; + channel_timestamp_active(client_relay3); +} + +static void +free_mock_network(void) +{ + free_fake_channeltls((channel_tls_t*)relay1_relay2); + free_fake_channeltls((channel_tls_t*)relay2_relay1); + free_fake_channeltls((channel_tls_t*)relay3_client); + free_fake_channeltls((channel_tls_t*)client_relay3); + + SMARTLIST_FOREACH(current_md_consensus->routerstatus_list, void *, r, + tor_free(r)); + smartlist_free(current_md_consensus->routerstatus_list); + smartlist_free(current_ns_consensus->net_params); + smartlist_free(connection_array); + tor_free(current_ns_consensus); +} + +static void +dummy_timer_cb(tor_timer_t *t, void *arg, const monotime_t *now_mono) +{ + (void)t; (void)arg; (void)now_mono; + event_base_loopbreak(tor_libevent_get_base()); + return; +} + +// This hack adds a dummy timer so that the libevent base loop +// actually returns when we don't expect any timers to fire. Otherwise, +// the global_timer_event gets scheduled an hour from now, and the +// base loop never returns. +void +dummy_nop_timer(void) +{ + tor_timer_t *dummy_timer = timer_new(dummy_timer_cb, NULL); + struct timeval timeout; + timeout.tv_sec = 1; + timeout.tv_usec = 0; + + timer_schedule(dummy_timer, &timeout); + + event_base_loop(tor_libevent_get_base(), 0); + timer_free(dummy_timer); +} + +#define CHANNELPADDING_MAX_TIMERS 25 +#define CHANNELS_TO_TEST (CHANNELPADDING_MAX_TIMERS*4) +/** + * Tests to ensure that we handle more than the max number of pending + * timers properly. + */ +void +test_channelpadding_timers(void *arg) +{ + channelpadding_decision_t decision; + channel_t *chans[CHANNELS_TO_TEST]; + (void)arg; + connection_array = smartlist_new(); + + monotime_init(); + timers_initialize(); + channelpadding_new_consensus_params(NULL); + + for (int i = 0; i < CHANNELS_TO_TEST; i++) { + chans[i] = (channel_t*)new_fake_channeltls(0); + channel_timestamp_active(chans[i]); + } + + for (int j = 0; j < 2; j++) { + tried_to_write_cell = 0; + int i = 0; + + /* This loop fills our timerslot array with timers of increasing time + * until they fire */ + for (; i < CHANNELPADDING_MAX_TIMERS; i++) { + chans[i]->next_padding_time_ms = monotime_coarse_absolute_msec() + + 10 + i*4; + decision = channelpadding_decide_to_pad_channel(chans[i]); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_assert(chans[i]->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + } + + /* This loop should add timers to our existing lists in a weak + * pseudorandom pattern. It ensures that the lists can grow with multiple + * timers in them. */ + for (; i < CHANNELS_TO_TEST/2; i++) { + chans[i]->next_padding_time_ms = monotime_coarse_absolute_msec() + 10 + + i*3 % CHANNELPADDING_MAX_TIMERS; + decision = channelpadding_decide_to_pad_channel(chans[i]); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_assert(chans[i]->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + } + + /* This loop should add timers to the first position in the timerslot + * array, since its timeout is before all other timers. */ + for (; i < CHANNELS_TO_TEST/3; i++) { + chans[i]->next_padding_time_ms = monotime_coarse_absolute_msec() + 1; + decision = channelpadding_decide_to_pad_channel(chans[i]); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_assert(chans[i]->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + } + + /* This loop should add timers to the last position in the timerslot + * array, since its timeout is after all other timers. */ + for (; i < CHANNELS_TO_TEST; i++) { + chans[i]->next_padding_time_ms = monotime_coarse_absolute_msec() + 500 + + i % CHANNELPADDING_MAX_TIMERS; + decision = channelpadding_decide_to_pad_channel(chans[i]); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_assert(chans[i]->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + } + + // Wait for the timers and then kill the event loop. + dont_stop_libevent = 1; + dummy_nop_timer(); + + tt_int_op(tried_to_write_cell, OP_EQ, CHANNELS_TO_TEST); + + // Test that we have no pending callbacks and all empty slots now + for (i = 0; i < CHANNELS_TO_TEST; i++) { + tt_assert(!chans[i]->pending_padding_callback); + } + } + + done: + for (int i = 0; i < CHANNELS_TO_TEST; i++) { + free_fake_channeltls((channel_tls_t*)chans[i]); + } + smartlist_free(connection_array); + + timers_shutdown(); + channel_free_all(); + + return; +} + +void +test_channelpadding_consensus(void *arg) +{ + channelpadding_decision_t decision; + or_options_t *options = get_options_mutable(); + int64_t val; + (void)arg; + + /* + * Params tested: + * nf_pad_before_usage + * nf_pad_relays + * nf_ito_low + * nf_ito_high + * + * Plan: + * 1. Padding can be completely disabled via consensus + * 2. Negotiation can't re-enable consensus-disabled padding + * 3. Negotiation can't increase padding from relays beyond + * consensus defaults + * 4. Relay-to-relay padding can be enabled/disabled in consensus + * 5. Can enable/disable padding before actually using a connection + * 6. Can we control circ and TLS conn lifetime from the consensus? + */ + channel_t *chan; + routerstatus_t *relay = tor_malloc_zero(sizeof(routerstatus_t)); + monotime_init(); + timers_initialize(); + + connection_array = smartlist_new(); + chan = (channel_t*)new_fake_channeltls(0); + channel_timestamp_active(chan); + + current_md_consensus = current_ns_consensus + = tor_malloc_zero(sizeof(networkstatus_t)); + current_md_consensus->net_params = smartlist_new(); + current_md_consensus->routerstatus_list = smartlist_new(); + channelpadding_new_consensus_params(current_md_consensus); + + get_options_mutable()->ORPort_set = 1; + + /* Test 1: Padding can be completely disabled via consensus */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec() + 100; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_assert(chan->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_ALREADY_SCHEDULED); + + // Wait for the timer + event_base_loop(tor_libevent_get_base(), 0); + tt_int_op(tried_to_write_cell, OP_EQ, 1); + tt_assert(!chan->pending_padding_callback); + + smartlist_add(current_md_consensus->net_params, + (void*)"nf_ito_low=0"); + smartlist_add(current_md_consensus->net_params, + (void*)"nf_ito_high=0"); + get_options_mutable()->ConnectionPadding = 1; + channelpadding_new_consensus_params(current_md_consensus); + + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_WONTPAD); + tt_assert(!chan->pending_padding_callback); + val = channelpadding_get_netflow_inactive_timeout_ms(chan); + tt_int_op(val, OP_EQ, 0); + val = channelpadding_compute_time_until_pad_for_netflow(chan); + tt_int_op(val, OP_EQ, -2); + + /* Test 2: Negotiation can't re-enable consensus-disabled padding */ + channelpadding_send_enable_command(chan, 100, 200); + tried_to_write_cell = 0; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_WONTPAD); + tt_assert(!chan->pending_padding_callback); + val = channelpadding_get_netflow_inactive_timeout_ms(chan); + tt_int_op(val, OP_EQ, 0); + val = channelpadding_compute_time_until_pad_for_netflow(chan); + tt_int_op(val, OP_EQ, -2); + tt_assert(!chan->next_padding_time_ms); + + smartlist_clear(current_md_consensus->net_params); + + /* Test 3: Negotiation can't increase padding from relays beyond consensus + * values */ + smartlist_add(current_md_consensus->net_params, + (void*)"nf_ito_low=100"); + smartlist_add(current_md_consensus->net_params, + (void*)"nf_ito_high=200"); + channelpadding_new_consensus_params(current_md_consensus); + + tried_to_write_cell = 0; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_assert(chan->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + val = channelpadding_get_netflow_inactive_timeout_ms(chan); + tt_int_op(val, OP_GE, 100); + tt_int_op(val, OP_LE, 200); + val = channelpadding_compute_time_until_pad_for_netflow(chan); + tt_int_op(val, OP_LE, 200); + + // Wait for the timer + event_base_loop(tor_libevent_get_base(), 0); + tt_int_op(tried_to_write_cell, OP_EQ, 1); + tt_assert(!chan->pending_padding_callback); + + smartlist_clear(current_md_consensus->net_params); + smartlist_add(current_md_consensus->net_params, + (void*)"nf_ito_low=1500"); + smartlist_add(current_md_consensus->net_params, + (void*)"nf_ito_high=4500"); + channelpadding_new_consensus_params(current_md_consensus); + + channelpadding_send_enable_command(chan, 100, 200); + tried_to_write_cell = 0; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADLATER); + tt_assert(!chan->pending_padding_callback); + val = channelpadding_get_netflow_inactive_timeout_ms(chan); + tt_int_op(val, OP_GE, 1500); + tt_int_op(val, OP_LE, 4500); + val = channelpadding_compute_time_until_pad_for_netflow(chan); + tt_int_op(val, OP_LE, 4500); + + /* Test 4: Relay-to-relay padding can be enabled/disabled in consensus */ + /* Make this channel a relay's channel */ + memcpy(relay->identity_digest, + ((channel_tls_t *)chan)->conn->identity_digest, DIGEST_LEN); + smartlist_add(current_md_consensus->routerstatus_list, relay); + + tried_to_write_cell = 0; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_WONTPAD); + tt_assert(!chan->pending_padding_callback); + + smartlist_add(current_md_consensus->net_params, + (void*)"nf_pad_relays=1"); + channelpadding_new_consensus_params(current_md_consensus); + + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADLATER); + tt_assert(!chan->pending_padding_callback); + val = channelpadding_get_netflow_inactive_timeout_ms(chan); + tt_int_op(val, OP_GE, 1500); + tt_int_op(val, OP_LE, 4500); + val = channelpadding_compute_time_until_pad_for_netflow(chan); + tt_int_op(val, OP_LE, 4500); + + /* Test 5: If we disable padding before channel usage, does that work? */ + smartlist_add(current_md_consensus->net_params, + (void*)"nf_pad_before_usage=0"); + channelpadding_new_consensus_params(current_md_consensus); + tried_to_write_cell = 0; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_WONTPAD); + tt_assert(!chan->pending_padding_callback); + + /* Test 6: Can we control circ and TLS conn lifetime from the consensus? */ + val = channelpadding_get_channel_idle_timeout(NULL, 0); + tt_int_op(val, OP_GE, 180); + tt_int_op(val, OP_LE, 180+90); + val = channelpadding_get_channel_idle_timeout(chan, 0); + tt_int_op(val, OP_GE, 180); + tt_int_op(val, OP_LE, 180+90); + options->ReducedConnectionPadding = 1; + val = channelpadding_get_channel_idle_timeout(chan, 0); + tt_int_op(val, OP_GE, 180/2); + tt_int_op(val, OP_LE, (180+90)/2); + + options->ReducedConnectionPadding = 0; + options->ORPort_set = 1; + smartlist_add(current_md_consensus->net_params, + (void*)"nf_conntimeout_relays=600"); + channelpadding_new_consensus_params(current_md_consensus); + val = channelpadding_get_channel_idle_timeout(chan, 1); + tt_int_op(val, OP_GE, 450); + tt_int_op(val, OP_LE, 750); + + val = channelpadding_get_circuits_available_timeout(); + tt_int_op(val, OP_GE, 30*60); + tt_int_op(val, OP_LE, 30*60*2); + + options->ReducedConnectionPadding = 1; + smartlist_add(current_md_consensus->net_params, + (void*)"nf_conntimeout_clients=600"); + channelpadding_new_consensus_params(current_md_consensus); + val = channelpadding_get_circuits_available_timeout(); + tt_int_op(val, OP_GE, 600/2); + tt_int_op(val, OP_LE, 600*2/2); + + options->ReducedConnectionPadding = 0; + options->CircuitsAvailableTimeout = 24*60*60; + val = channelpadding_get_circuits_available_timeout(); + tt_int_op(val, OP_GE, 24*60*60); + tt_int_op(val, OP_LE, 24*60*60*2); + + done: + free_fake_channeltls((channel_tls_t*)chan); + smartlist_free(connection_array); + smartlist_free(current_md_consensus->routerstatus_list); + smartlist_free(current_ns_consensus->net_params); + tor_free(relay); + tor_free(current_ns_consensus); + + timers_shutdown(); + channel_free_all(); + + return; +} + +void +test_channelpadding_negotiation(void *arg) +{ + channelpadding_negotiate_t disable; + cell_t cell; + channelpadding_decision_t decision; + int val; + (void)arg; + + /* Plan: + * 1. Clients reject negotiation, relays accept it. + * * Bridges accept negotiation from their clients, + * but not from relays. + * 2. Torrc options can override client-side negotiation + * 3. Test a version issue in channelpadidng cell + * 4. Test channelpadding_reduced_padding + */ + monotime_init(); + timers_initialize(); + setup_mock_network(); + + /* Test case #1: Do the right things ignore negotiation? */ + /* relay-to-client case: */ + channelpadding_send_disable_command(relay3_client); + tt_assert(client_relay3->padding_enabled); + + /* client-to-relay case: */ + get_options_mutable()->ORPort_set = 1; + channelpadding_disable_padding_on_channel(client_relay3); + tt_int_op(channelpadding_decide_to_pad_channel(relay3_client), OP_EQ, + CHANNELPADDING_WONTPAD); + tt_assert(!relay3_client->padding_enabled); + relay3_client->padding_enabled = 1; + client_relay3->padding_enabled = 1; + + /* Bridge case from relay */ + get_options_mutable()->BridgeRelay = 1; + channelpadding_disable_padding_on_channel(relay2_relay1); + tt_assert(relay1_relay2->padding_enabled); + + /* Bridge case from client */ + channelpadding_disable_padding_on_channel(client_relay3); + tt_assert(!relay3_client->padding_enabled); + tt_int_op(channelpadding_decide_to_pad_channel(relay3_client), OP_EQ, + CHANNELPADDING_WONTPAD); + relay3_client->padding_enabled = 1; + client_relay3->padding_enabled = 1; + get_options_mutable()->BridgeRelay = 0; + get_options_mutable()->ORPort_set = 0; + + /* Test case #2: Torrc options */ + /* ConnectionPadding auto; Relay doesn't suport us */ + ((channel_tls_t*)relay3_client)->conn->link_proto = 4; + relay3_client->padding_enabled = 0; + tried_to_write_cell = 0; + decision = channelpadding_decide_to_pad_channel(relay3_client); + tt_int_op(decision, OP_EQ, CHANNELPADDING_WONTPAD); + tt_assert(!relay3_client->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + ((channel_tls_t*)relay3_client)->conn->link_proto = 5; + relay3_client->padding_enabled = 1; + + /* ConnectionPadding 1; Relay doesn't suport us */ + get_options_mutable()->ConnectionPadding = 1; + tried_to_write_cell = 0; + decision = channelpadding_decide_to_pad_channel(client_relay3); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADLATER); + tt_assert(!client_relay3->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + get_options_mutable()->ConnectionPadding = 0; + + /* Test case #3: Test a version issue in channelpadding cell */ + get_options_mutable()->ORPort_set = 1; + client_relay3->padding_enabled = 1; + relay3_client->padding_enabled = 1; + memset(&cell, 0, sizeof(cell_t)); + memset(&disable, 0, sizeof(channelpadding_negotiate_t)); + cell.command = CELL_PADDING_NEGOTIATE; + + channelpadding_negotiate_set_command(&disable, CHANNELPADDING_COMMAND_STOP); + disable.version = 1; + channelpadding_negotiate_encode(cell.payload, CELL_PAYLOAD_SIZE, &disable); + client_relay3->write_cell(client_relay3, &cell); + tt_assert(relay3_client->padding_enabled); + tt_int_op(channelpadding_update_padding_for_channel(client_relay3, &disable), + OP_EQ, -1); + tt_assert(client_relay3->padding_enabled); + + disable.version = 0; + channelpadding_negotiate_encode(cell.payload, CELL_PAYLOAD_SIZE, &disable); + client_relay3->write_cell(client_relay3, &cell); + tt_assert(!relay3_client->padding_enabled); + + /* Test case 4: Reducing padding actually reduces it */ + relay3_client->padding_enabled = 1; + client_relay3->padding_enabled = 1; + + decision = channelpadding_decide_to_pad_channel(relay3_client); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADLATER); + + channelpadding_reduce_padding_on_channel(client_relay3); + + tried_to_write_cell = 0; + decision = channelpadding_decide_to_pad_channel(relay3_client); + tt_int_op(decision, OP_EQ, CHANNELPADDING_WONTPAD); + + get_options_mutable()->ORPort_set = 0; + decision = channelpadding_decide_to_pad_channel(client_relay3); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADLATER); + + tt_assert(!client_relay3->pending_padding_callback); + val = channelpadding_get_netflow_inactive_timeout_ms(client_relay3); + tt_int_op(val, OP_GE, 9000); + tt_int_op(val, OP_LE, 14000); + val = channelpadding_compute_time_until_pad_for_netflow(client_relay3); + tt_int_op(val, OP_LE, 14000); + + done: + free_mock_network(); + + timers_shutdown(); + channel_free_all(); + + return; +} + +void +test_channelpadding_decide_to_pad_channel(void *arg) +{ + channelpadding_decision_t decision; + /** + * Test case plan: + * + * 1. Channel that has "sent a packet" before the timeout. + * + We should decide to pad later + * 2. Channel that has not "sent a packet" before the timeout: + * 2a. Not within 1.1s of the timeout. + * + We should decide to pad later + * 2b. Within 1.1s of the timemout. + * + We should schedule padding + * + We should get feedback that we wrote a cell + * 2c. Within 0.1s of the timeout. + * + We should schedule padding + * + We should get feedback that we wrote a cell + * 2d. Channel that asks to pad while timeout is scheduled + * + We should schedule padding + * + We should get feedback that we wrote a cell + * 2e. 0s of the timeout + * + We should send padding immediately + * + We should get feedback that we wrote a cell + * 2f. <0s of the timeout + * + We should send padding immediately + * + We should get feedback that we wrote a cell + * 3. Channel that sends a packet while timeout is scheduled + * + We should not get feedback that we wrote a cell + * 4. Channel that closes while timeout is scheduled + * + We should not get feedback that we wrote a cell + * 5. Make sure the channel still would work if repaired + * + We should be able to schedule padding and resend + * 6. Channel is not used for full circuits + * 7. Channel that disappears while timeout is scheduled + * + We should not send padding + */ + channel_t *chan; + connection_array = smartlist_new(); + (void)arg; + + monotime_init(); + timers_initialize(); + setup_full_capture_of_logs(LOG_WARN); + channelpadding_new_consensus_params(NULL); + + chan = (channel_t*)new_fake_channeltls(0); + channel_timestamp_active(chan); + + /* Test case #1: Channel that has "sent a packet" before the timeout. */ + tried_to_write_cell = 0; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADLATER); + tt_assert(!chan->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + + /* Test case #2a: > 1.1s until timeout */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec() + 1200; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADLATER); + tt_assert(!chan->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + + /* Test case #2b: >= 1.0s until timeout */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec() + 1000; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_assert(chan->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + + // Wait for the timer from case #2b + event_base_loop(tor_libevent_get_base(), 0); + tt_int_op(tried_to_write_cell, OP_EQ, 1); + tt_assert(!chan->pending_padding_callback); + + /* Test case #2c: > 0.1s until timeout */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec() + 100; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_assert(chan->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + + /* Test case #2d: Channel that asks to pad while timeout is scheduled */ + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_ALREADY_SCHEDULED); + + // Wait for the timer + event_base_loop(tor_libevent_get_base(), 0); + tt_int_op(tried_to_write_cell, OP_EQ, 1); + tt_assert(!chan->pending_padding_callback); + + /* Test case #2e: 0s until timeout */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec(); + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SENT); + tt_int_op(tried_to_write_cell, OP_EQ, 1); + tt_assert(!chan->pending_padding_callback); + + /* Test case #2f: <0s until timeout */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec() - 100; + decision = channelpadding_decide_to_pad_channel(chan); + expect_log_msg("Channel padding timeout scheduled 100ms in the past. " + "Did the monotonic clock just jump?\n"); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SENT); + tt_int_op(tried_to_write_cell, OP_EQ, 1); + tt_assert(!chan->pending_padding_callback); + + /* Test case #3: Channel that sends a packet while timeout is scheduled */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec() + 100; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + tt_assert(chan->pending_padding_callback); + + // Pretend the channel sent a packet + channel_timestamp_active(chan); + + // We don't expect any timer callbacks here. Make a dummy one to be sure. + dummy_nop_timer(); + + tt_int_op(tried_to_write_cell, OP_EQ, 0); + tt_assert(!chan->pending_padding_callback); + + /* Test case #4: Channel that closes while a timeout is scheduled */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec() + 100; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + tt_assert(chan->pending_padding_callback); + + // Pretend the channel is temporarily down + chan->state = CHANNEL_STATE_MAINT; + + // We don't expect any timer callbacks here. Make a dummy one to be sure. + dummy_nop_timer(); + + tt_int_op(tried_to_write_cell, OP_EQ, 0); + tt_assert(!chan->pending_padding_callback); + chan->state = CHANNEL_STATE_OPEN; + + /* Test case #5: Make sure previous test case didn't break everything */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec() + 100; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_assert(chan->pending_padding_callback); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + + // Wait for the timer + event_base_loop(tor_libevent_get_base(), 0); + tt_int_op(tried_to_write_cell, OP_EQ, 1); + tt_assert(!chan->pending_padding_callback); + + /* Test case #6. Channel is not used for full circuits */ + chan->channel_usage = CHANNEL_USED_NOT_USED_FOR_FULL_CIRCS; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_WONTPAD); + tt_assert(!chan->pending_padding_callback); + chan->channel_usage = CHANNEL_USED_FOR_FULL_CIRCS; + + /* Test case #7. Channel is closed while timeout is scheduled. + * + * NOTE: This test deliberately breaks the channel callback mechanism. + * It must be last. + */ + tried_to_write_cell = 0; + chan->next_padding_time_ms = monotime_coarse_absolute_msec() + 100; + decision = channelpadding_decide_to_pad_channel(chan); + tt_int_op(decision, OP_EQ, CHANNELPADDING_PADDING_SCHEDULED); + tt_int_op(tried_to_write_cell, OP_EQ, 0); + tt_assert(chan->pending_padding_callback); + + // Close the connection while the timer is scheduled + free_fake_channeltls((channel_tls_t*)chan); + + // We don't expect any timer callbacks here. Make a dummy one to be sure. + dummy_nop_timer(); + + tt_int_op(tried_to_write_cell, OP_EQ, 0); + + done: + smartlist_free(connection_array); + + teardown_capture_of_logs(); + timers_shutdown(); + channel_free_all(); + + return; +} + +#define TEST_CHANNELPADDING(name, flags) \ + { #name, test_##name, (flags), NULL, NULL } + +struct testcase_t channelpadding_tests[] = { + //TEST_CHANNELPADDING(channelpadding_decide_to_pad_channel, 0), + TEST_CHANNELPADDING(channelpadding_decide_to_pad_channel, TT_FORK), + TEST_CHANNELPADDING(channelpadding_negotiation, TT_FORK), + TEST_CHANNELPADDING(channelpadding_consensus, TT_FORK), + TEST_CHANNELPADDING(channelpadding_timers, TT_FORK), + END_OF_TESTCASES +}; + diff --git a/src/test/test_options.c b/src/test/test_options.c index 68e7ffc682..e2fc034cc3 100644 --- a/src/test/test_options.c +++ b/src/test/test_options.c @@ -415,6 +415,12 @@ get_options_test_data(const char *conf) result->opt = options_new(); result->old_opt = options_new(); result->def_opt = options_new(); + + // XXX: Really, all of these options should be set to defaults + // with options_init(), but about a dozen tests break when I do that. + // Being kinda lame and just fixing the immedate breakage for now.. + result->opt->ConnectionPadding = -1; // default must be "auto" + rv = config_get_lines(conf, &cl, 1); tt_assert(rv == 0); rv = config_assign(&options_format, result->opt, cl, 0, &msg); @@ -2388,30 +2394,6 @@ test_options_validate__hidserv(void *ignored) } static void -test_options_validate__predicted_ports(void *ignored) -{ - (void)ignored; - int ret; - char *msg; - setup_capture_of_logs(LOG_WARN); - - options_test_data_t *tdata = get_options_test_data( - "PredictedPortsRelevanceTime 100000000\n" - TEST_OPTIONS_DEFAULT_VALUES); - ret = options_validate(tdata->old_opt, tdata->opt, tdata->def_opt, 0, &msg); - tt_int_op(ret, OP_EQ, 0); - expect_log_msg("PredictedPortsRelevanceTime is too " - "large; clipping to 3600s.\n"); - tt_int_op(tdata->opt->PredictedPortsRelevanceTime, OP_EQ, 3600); - - done: - teardown_capture_of_logs(); - policies_free_all(); - free_options_test_data(tdata); - tor_free(msg); -} - -static void test_options_validate__path_bias(void *ignored) { (void)ignored; @@ -4596,7 +4578,6 @@ struct testcase_t options_tests[] = { LOCAL_VALIDATE_TEST(publish_server_descriptor), LOCAL_VALIDATE_TEST(testing), LOCAL_VALIDATE_TEST(hidserv), - LOCAL_VALIDATE_TEST(predicted_ports), LOCAL_VALIDATE_TEST(path_bias), LOCAL_VALIDATE_TEST(bandwidth), LOCAL_VALIDATE_TEST(circuits), diff --git a/src/test/testing_common.c b/src/test/testing_common.c index d3dc761c77..d7e36edbc0 100644 --- a/src/test/testing_common.c +++ b/src/test/testing_common.c @@ -21,6 +21,7 @@ const char tor_git_revision[] = ""; #include "rephist.h" #include "backtrace.h" #include "test.h" +#include "channelpadding.h" #include <stdio.h> #ifdef HAVE_FCNTL_H @@ -304,10 +305,15 @@ main(int c, const char **v) tor_free(errmsg); return 1; } + tor_set_failed_assertion_callback(an_assertion_failed); init_pregenerated_keys(); + channelpadding_new_consensus_params(NULL); + + predicted_ports_init(); + atexit(remove_directory); int have_failed = (tinytest_main(c, v, testgroups) != 0); diff --git a/src/trunnel/channelpadding_negotiation.c b/src/trunnel/channelpadding_negotiation.c new file mode 100644 index 0000000000..172d6f8a03 --- /dev/null +++ b/src/trunnel/channelpadding_negotiation.c @@ -0,0 +1,281 @@ +/* channelpadding_negotiation.c -- generated by Trunnel v1.4.3. + * https://gitweb.torproject.org/trunnel.git + * You probably shouldn't edit this file. + */ +#include <stdlib.h> +#include "trunnel-impl.h" + +#include "channelpadding_negotiation.h" + +#define TRUNNEL_SET_ERROR_CODE(obj) \ + do { \ + (obj)->trunnel_error_code_ = 1; \ + } while (0) + +#if defined(__COVERITY__) || defined(__clang_analyzer__) +/* If we're runnning a static analysis tool, we don't want it to complain + * that some of our remaining-bytes checks are dead-code. */ +int channelpaddingnegotiation_deadcode_dummy__ = 0; +#define OR_DEADCODE_DUMMY || channelpaddingnegotiation_deadcode_dummy__ +#else +#define OR_DEADCODE_DUMMY +#endif + +#define CHECK_REMAINING(nbytes, label) \ + do { \ + if (remaining < (nbytes) OR_DEADCODE_DUMMY) { \ + goto label; \ + } \ + } while (0) + +channelpadding_negotiate_t * +channelpadding_negotiate_new(void) +{ + channelpadding_negotiate_t *val = trunnel_calloc(1, sizeof(channelpadding_negotiate_t)); + if (NULL == val) + return NULL; + val->command = CHANNELPADDING_COMMAND_START; + return val; +} + +/** Release all storage held inside 'obj', but do not free 'obj'. + */ +static void +channelpadding_negotiate_clear(channelpadding_negotiate_t *obj) +{ + (void) obj; +} + +void +channelpadding_negotiate_free(channelpadding_negotiate_t *obj) +{ + if (obj == NULL) + return; + channelpadding_negotiate_clear(obj); + trunnel_memwipe(obj, sizeof(channelpadding_negotiate_t)); + trunnel_free_(obj); +} + +uint8_t +channelpadding_negotiate_get_version(channelpadding_negotiate_t *inp) +{ + return inp->version; +} +int +channelpadding_negotiate_set_version(channelpadding_negotiate_t *inp, uint8_t val) +{ + if (! ((val == 0))) { + TRUNNEL_SET_ERROR_CODE(inp); + return -1; + } + inp->version = val; + return 0; +} +uint8_t +channelpadding_negotiate_get_command(channelpadding_negotiate_t *inp) +{ + return inp->command; +} +int +channelpadding_negotiate_set_command(channelpadding_negotiate_t *inp, uint8_t val) +{ + if (! ((val == CHANNELPADDING_COMMAND_START || val == CHANNELPADDING_COMMAND_STOP))) { + TRUNNEL_SET_ERROR_CODE(inp); + return -1; + } + inp->command = val; + return 0; +} +uint16_t +channelpadding_negotiate_get_ito_low_ms(channelpadding_negotiate_t *inp) +{ + return inp->ito_low_ms; +} +int +channelpadding_negotiate_set_ito_low_ms(channelpadding_negotiate_t *inp, uint16_t val) +{ + inp->ito_low_ms = val; + return 0; +} +uint16_t +channelpadding_negotiate_get_ito_high_ms(channelpadding_negotiate_t *inp) +{ + return inp->ito_high_ms; +} +int +channelpadding_negotiate_set_ito_high_ms(channelpadding_negotiate_t *inp, uint16_t val) +{ + inp->ito_high_ms = val; + return 0; +} +const char * +channelpadding_negotiate_check(const channelpadding_negotiate_t *obj) +{ + if (obj == NULL) + return "Object was NULL"; + if (obj->trunnel_error_code_) + return "A set function failed on this object"; + if (! (obj->version == 0)) + return "Integer out of bounds"; + if (! (obj->command == CHANNELPADDING_COMMAND_START || obj->command == CHANNELPADDING_COMMAND_STOP)) + return "Integer out of bounds"; + return NULL; +} + +ssize_t +channelpadding_negotiate_encoded_len(const channelpadding_negotiate_t *obj) +{ + ssize_t result = 0; + + if (NULL != channelpadding_negotiate_check(obj)) + return -1; + + + /* Length of u8 version IN [0] */ + result += 1; + + /* Length of u8 command IN [CHANNELPADDING_COMMAND_START, CHANNELPADDING_COMMAND_STOP] */ + result += 1; + + /* Length of u16 ito_low_ms */ + result += 2; + + /* Length of u16 ito_high_ms */ + result += 2; + return result; +} +int +channelpadding_negotiate_clear_errors(channelpadding_negotiate_t *obj) +{ + int r = obj->trunnel_error_code_; + obj->trunnel_error_code_ = 0; + return r; +} +ssize_t +channelpadding_negotiate_encode(uint8_t *output, const size_t avail, const channelpadding_negotiate_t *obj) +{ + ssize_t result = 0; + size_t written = 0; + uint8_t *ptr = output; + const char *msg; +#ifdef TRUNNEL_CHECK_ENCODED_LEN + const ssize_t encoded_len = channelpadding_negotiate_encoded_len(obj); +#endif + + if (NULL != (msg = channelpadding_negotiate_check(obj))) + goto check_failed; + +#ifdef TRUNNEL_CHECK_ENCODED_LEN + trunnel_assert(encoded_len >= 0); +#endif + + /* Encode u8 version IN [0] */ + trunnel_assert(written <= avail); + if (avail - written < 1) + goto truncated; + trunnel_set_uint8(ptr, (obj->version)); + written += 1; ptr += 1; + + /* Encode u8 command IN [CHANNELPADDING_COMMAND_START, CHANNELPADDING_COMMAND_STOP] */ + trunnel_assert(written <= avail); + if (avail - written < 1) + goto truncated; + trunnel_set_uint8(ptr, (obj->command)); + written += 1; ptr += 1; + + /* Encode u16 ito_low_ms */ + trunnel_assert(written <= avail); + if (avail - written < 2) + goto truncated; + trunnel_set_uint16(ptr, trunnel_htons(obj->ito_low_ms)); + written += 2; ptr += 2; + + /* Encode u16 ito_high_ms */ + trunnel_assert(written <= avail); + if (avail - written < 2) + goto truncated; + trunnel_set_uint16(ptr, trunnel_htons(obj->ito_high_ms)); + written += 2; ptr += 2; + + + trunnel_assert(ptr == output + written); +#ifdef TRUNNEL_CHECK_ENCODED_LEN + { + trunnel_assert(encoded_len >= 0); + trunnel_assert((size_t)encoded_len == written); + } + +#endif + + return written; + + truncated: + result = -2; + goto fail; + check_failed: + (void)msg; + result = -1; + goto fail; + fail: + trunnel_assert(result < 0); + return result; +} + +/** As channelpadding_negotiate_parse(), but do not allocate the + * output object. + */ +static ssize_t +channelpadding_negotiate_parse_into(channelpadding_negotiate_t *obj, const uint8_t *input, const size_t len_in) +{ + const uint8_t *ptr = input; + size_t remaining = len_in; + ssize_t result = 0; + (void)result; + + /* Parse u8 version IN [0] */ + CHECK_REMAINING(1, truncated); + obj->version = (trunnel_get_uint8(ptr)); + remaining -= 1; ptr += 1; + if (! (obj->version == 0)) + goto fail; + + /* Parse u8 command IN [CHANNELPADDING_COMMAND_START, CHANNELPADDING_COMMAND_STOP] */ + CHECK_REMAINING(1, truncated); + obj->command = (trunnel_get_uint8(ptr)); + remaining -= 1; ptr += 1; + if (! (obj->command == CHANNELPADDING_COMMAND_START || obj->command == CHANNELPADDING_COMMAND_STOP)) + goto fail; + + /* Parse u16 ito_low_ms */ + CHECK_REMAINING(2, truncated); + obj->ito_low_ms = trunnel_ntohs(trunnel_get_uint16(ptr)); + remaining -= 2; ptr += 2; + + /* Parse u16 ito_high_ms */ + CHECK_REMAINING(2, truncated); + obj->ito_high_ms = trunnel_ntohs(trunnel_get_uint16(ptr)); + remaining -= 2; ptr += 2; + trunnel_assert(ptr + remaining == input + len_in); + return len_in - remaining; + + truncated: + return -2; + fail: + result = -1; + return result; +} + +ssize_t +channelpadding_negotiate_parse(channelpadding_negotiate_t **output, const uint8_t *input, const size_t len_in) +{ + ssize_t result; + *output = channelpadding_negotiate_new(); + if (NULL == *output) + return -1; + result = channelpadding_negotiate_parse_into(*output, input, len_in); + if (result < 0) { + channelpadding_negotiate_free(*output); + *output = NULL; + } + return result; +} diff --git a/src/trunnel/channelpadding_negotiation.h b/src/trunnel/channelpadding_negotiation.h new file mode 100644 index 0000000000..e58bda3be1 --- /dev/null +++ b/src/trunnel/channelpadding_negotiation.h @@ -0,0 +1,98 @@ +/* channelpadding_negotiation.h -- generated by by Trunnel v1.4.3. + * https://gitweb.torproject.org/trunnel.git + * You probably shouldn't edit this file. + */ +#ifndef TRUNNEL_CHANNELPADDING_NEGOTIATION_H +#define TRUNNEL_CHANNELPADDING_NEGOTIATION_H + +#include <stdint.h> +#include "trunnel.h" + +#define CHANNELPADDING_COMMAND_STOP 1 +#define CHANNELPADDING_COMMAND_START 2 +#if !defined(TRUNNEL_OPAQUE) && !defined(TRUNNEL_OPAQUE_CHANNELPADDING_NEGOTIATE) +struct channelpadding_negotiate_st { + uint8_t version; + uint8_t command; + uint16_t ito_low_ms; + uint16_t ito_high_ms; + uint8_t trunnel_error_code_; +}; +#endif +typedef struct channelpadding_negotiate_st channelpadding_negotiate_t; +/** Return a newly allocated channelpadding_negotiate with all + * elements set to zero. + */ +channelpadding_negotiate_t *channelpadding_negotiate_new(void); +/** Release all storage held by the channelpadding_negotiate in + * 'victim'. (Do nothing if 'victim' is NULL.) + */ +void channelpadding_negotiate_free(channelpadding_negotiate_t *victim); +/** Try to parse a channelpadding_negotiate from the buffer in + * 'input', using up to 'len_in' bytes from the input buffer. On + * success, return the number of bytes consumed and set *output to the + * newly allocated channelpadding_negotiate_t. On failure, return -2 + * if the input appears truncated, and -1 if the input is otherwise + * invalid. + */ +ssize_t channelpadding_negotiate_parse(channelpadding_negotiate_t **output, const uint8_t *input, const size_t len_in); +/** Return the number of bytes we expect to need to encode the + * channelpadding_negotiate in 'obj'. On failure, return a negative + * value. Note that this value may be an overestimate, and can even be + * an underestimate for certain unencodeable objects. + */ +ssize_t channelpadding_negotiate_encoded_len(const channelpadding_negotiate_t *obj); +/** Try to encode the channelpadding_negotiate from 'input' into the + * buffer at 'output', using up to 'avail' bytes of the output buffer. + * On success, return the number of bytes used. On failure, return -2 + * if the buffer was not long enough, and -1 if the input was invalid. + */ +ssize_t channelpadding_negotiate_encode(uint8_t *output, size_t avail, const channelpadding_negotiate_t *input); +/** Check whether the internal state of the channelpadding_negotiate + * in 'obj' is consistent. Return NULL if it is, and a short message + * if it is not. + */ +const char *channelpadding_negotiate_check(const channelpadding_negotiate_t *obj); +/** Clear any errors that were set on the object 'obj' by its setter + * functions. Return true iff errors were cleared. + */ +int channelpadding_negotiate_clear_errors(channelpadding_negotiate_t *obj); +/** Return the value of the version field of the + * channelpadding_negotiate_t in 'inp' + */ +uint8_t channelpadding_negotiate_get_version(channelpadding_negotiate_t *inp); +/** Set the value of the version field of the + * channelpadding_negotiate_t in 'inp' to 'val'. Return 0 on success; + * return -1 and set the error code on 'inp' on failure. + */ +int channelpadding_negotiate_set_version(channelpadding_negotiate_t *inp, uint8_t val); +/** Return the value of the command field of the + * channelpadding_negotiate_t in 'inp' + */ +uint8_t channelpadding_negotiate_get_command(channelpadding_negotiate_t *inp); +/** Set the value of the command field of the + * channelpadding_negotiate_t in 'inp' to 'val'. Return 0 on success; + * return -1 and set the error code on 'inp' on failure. + */ +int channelpadding_negotiate_set_command(channelpadding_negotiate_t *inp, uint8_t val); +/** Return the value of the ito_low_ms field of the + * channelpadding_negotiate_t in 'inp' + */ +uint16_t channelpadding_negotiate_get_ito_low_ms(channelpadding_negotiate_t *inp); +/** Set the value of the ito_low_ms field of the + * channelpadding_negotiate_t in 'inp' to 'val'. Return 0 on success; + * return -1 and set the error code on 'inp' on failure. + */ +int channelpadding_negotiate_set_ito_low_ms(channelpadding_negotiate_t *inp, uint16_t val); +/** Return the value of the ito_high_ms field of the + * channelpadding_negotiate_t in 'inp' + */ +uint16_t channelpadding_negotiate_get_ito_high_ms(channelpadding_negotiate_t *inp); +/** Set the value of the ito_high_ms field of the + * channelpadding_negotiate_t in 'inp' to 'val'. Return 0 on success; + * return -1 and set the error code on 'inp' on failure. + */ +int channelpadding_negotiate_set_ito_high_ms(channelpadding_negotiate_t *inp, uint16_t val); + + +#endif diff --git a/src/trunnel/channelpadding_negotiation.trunnel b/src/trunnel/channelpadding_negotiation.trunnel new file mode 100644 index 0000000000..7f2d4795b0 --- /dev/null +++ b/src/trunnel/channelpadding_negotiation.trunnel @@ -0,0 +1,17 @@ +const CHANNELPADDING_COMMAND_STOP = 1; +const CHANNELPADDING_COMMAND_START = 2; + +/* This command tells the relay to alter its min and max netflow + timeout range values, and send padding at that rate (resuming + if stopped). */ +struct channelpadding_negotiate { + u8 version IN [0]; + u8 command IN [CHANNELPADDING_COMMAND_START, CHANNELPADDING_COMMAND_STOP]; + + /* Min must not be lower than the current consensus parameter + nf_ito_low. */ + u16 ito_low_ms; + + /* Max must not be lower than ito_low_ms */ + u16 ito_high_ms; +}; diff --git a/src/trunnel/include.am b/src/trunnel/include.am index 9b26d58615..de6cf4781f 100644 --- a/src/trunnel/include.am +++ b/src/trunnel/include.am @@ -11,7 +11,8 @@ AM_CPPFLAGS += -I$(srcdir)/src/ext/trunnel -I$(srcdir)/src/trunnel TRUNNELINPUTS = \ src/trunnel/ed25519_cert.trunnel \ src/trunnel/link_handshake.trunnel \ - src/trunnel/pwbox.trunnel + src/trunnel/pwbox.trunnel \ + src/trunnel/channelpadding_negotiation.trunnel TRUNNELSOURCES = \ src/ext/trunnel/trunnel.c \ @@ -20,7 +21,8 @@ TRUNNELSOURCES = \ src/trunnel/pwbox.c \ src/trunnel/hs/cell_common.c \ src/trunnel/hs/cell_establish_intro.c \ - src/trunnel/hs/cell_introduce1.c + src/trunnel/hs/cell_introduce1.c \ + src/trunnel/channelpadding_negotiation.c TRUNNELHEADERS = \ src/ext/trunnel/trunnel.h \ @@ -31,7 +33,8 @@ TRUNNELHEADERS = \ src/trunnel/pwbox.h \ src/trunnel/hs/cell_common.h \ src/trunnel/hs/cell_establish_intro.h \ - src/trunnel/hs/cell_introduce1.h + src/trunnel/hs/cell_introduce1.h \ + src/trunnel/channelpadding_negotiation.h src_trunnel_libor_trunnel_a_SOURCES = $(TRUNNELSOURCES) src_trunnel_libor_trunnel_a_CPPFLAGS = -DTRUNNEL_LOCAL_H $(AM_CPPFLAGS) |