diff options
Diffstat (limited to 'src/or')
| -rw-r--r-- | src/or/Makefile.nmake | 1 | ||||
| -rw-r--r-- | src/or/channel.c | 42 | ||||
| -rw-r--r-- | src/or/channel.h | 83 | ||||
| -rw-r--r-- | src/or/channelpadding.c | 574 | ||||
| -rw-r--r-- | src/or/channelpadding.h | 38 | ||||
| -rw-r--r-- | src/or/channeltls.c | 56 | ||||
| -rw-r--r-- | src/or/circuitbuild.c | 11 | ||||
| -rw-r--r-- | src/or/command.c | 22 | ||||
| -rw-r--r-- | src/or/config.c | 11 | ||||
| -rw-r--r-- | src/or/connection_or.c | 16 | ||||
| -rw-r--r-- | src/or/connection_or.h | 2 | ||||
| -rw-r--r-- | src/or/include.am | 2 | ||||
| -rw-r--r-- | src/or/main.c | 23 | ||||
| -rw-r--r-- | src/or/networkstatus.c | 4 | ||||
| -rw-r--r-- | src/or/or.h | 13 | ||||
| -rw-r--r-- | src/or/relay.c | 83 | ||||
| -rw-r--r-- | src/or/rephist.c | 206 | ||||
| -rw-r--r-- | src/or/rephist.h | 25 | ||||
| -rw-r--r-- | src/or/router.c | 6 |
19 files changed, 1203 insertions, 15 deletions
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 a1ccb2c8e3..74793436da 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 */ @@ -105,6 +107,8 @@ 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; /* @@ -922,6 +926,11 @@ 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); @@ -1000,6 +1009,11 @@ 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); @@ -2619,6 +2633,19 @@ 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); } @@ -4215,8 +4242,12 @@ 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; } /** @@ -4299,11 +4330,14 @@ 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; } /** @@ -4316,11 +4350,15 @@ 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 0b8f599895..21211dc8bd 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 @@ -37,6 +50,9 @@ struct channel_s { /** 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; @@ -51,6 +67,58 @@ 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; + + /** 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 { @@ -90,6 +158,18 @@ 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 */ @@ -633,5 +713,8 @@ 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..3976424faf --- /dev/null +++ b/src/or/channelpadding.c @@ -0,0 +1,574 @@ +/* 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; + +/** + * 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. + */ +#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 +STATIC int +channelpadding_get_netflow_inactive_timeout_ms(const channel_t *chan) +{ + int low_timeout = networkstatus_get_param(NULL, "nf_ito_low", + DFLT_NETFLOW_INACTIVE_KEEPALIVE_LOW, + DFLT_NETFLOW_INACTIVE_KEEPALIVE_MIN, + DFLT_NETFLOW_INACTIVE_KEEPALIVE_MAX); + int high_timeout = networkstatus_get_param(NULL, "nf_ito_high", + DFLT_NETFLOW_INACTIVE_KEEPALIVE_HIGH, + low_timeout, + DFLT_NETFLOW_INACTIVE_KEEPALIVE_MAX); + 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. Brides 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(networkstatus_get_param(NULL, + "nf_ito_low", + DFLT_NETFLOW_INACTIVE_KEEPALIVE_LOW, + DFLT_NETFLOW_INACTIVE_KEEPALIVE_MIN, + DFLT_NETFLOW_INACTIVE_KEEPALIVE_MAX), + 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(BASE_CHAN_TO_TLS(chan)->conn->base_.magic == + OR_CONNECTION_MAGIC); + assert_connection_ok(&BASE_CHAN_TO_TLS(chan)->conn->base_, 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/1000; + timeout.tv_usec = (in_ms%1000)*1000; + + 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) { + 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 calcualte the number of milliseconds + from now which we should send padding, so we can schedule a callback + then. + */ + if (long_now + 1100 >= 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; +} + +/** + * 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); + } + +#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 + chan->padding_timeout_low_ms = + networkstatus_get_param(NULL, "nf_ito_low_reduced", + DFLT_NETFLOW_REDUCED_KEEPALIVE_LOW, + DFLT_NETFLOW_REDUCED_KEEPALIVE_MIN, + DFLT_NETFLOW_REDUCED_KEEPALIVE_MAX); + + chan->padding_timeout_high_ms = + networkstatus_get_param(NULL, "nf_ito_high_reduced", + DFLT_NETFLOW_REDUCED_KEEPALIVE_HIGH, + chan->padding_timeout_low_ms, + DFLT_NETFLOW_REDUCED_KEEPALIVE_MAX); + + 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 (!networkstatus_get_param(NULL, "nf_pad_before_usage", 1, 0, 1)) + 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 (!public_server_mode(options) || chan->is_client || + !connection_or_digest_is_known_relay(chan->identity_digest)) { + 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 || + networkstatus_get_param(NULL, "nf_pad_relays", 0, 0, 1)) { + 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..07af7a6b46 --- /dev/null +++ b/src/or/channelpadding.h @@ -0,0 +1,38 @@ +/* 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 *); + +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); + +#endif + diff --git a/src/or/channeltls.c b/src/or/channeltls.c index dbed95fb43..155684c0ce 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() @@ -1098,9 +1103,16 @@ 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 (chan->base_.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 (chan->base_.currently_padding) + rep_hist_padding_count_read(PADDING_TYPE_ENABLED_CELL); ++stats_n_padding_cells_processed; /* do nothing */ break; @@ -1111,6 +1123,10 @@ 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: @@ -1570,6 +1586,9 @@ channel_tls_process_versions_cell(var_cell_t *cell, channel_tls_t *chan) chan->conn->link_proto >= MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS; chan->conn->wide_circ_ids = chan->base_.wide_circ_ids; + chan->base_.padding_enabled = + chan->conn->link_proto >= MIN_LINK_PROTO_FOR_CHANNEL_PADDING; + if (send_certs) { if (connection_or_send_certs_cell(chan->conn) < 0) { log_warn(LD_OR, "Couldn't send certs cell"); @@ -1595,6 +1614,43 @@ 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 diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c index cd00034395..24b7c7f4d9 100644 --- a/src/or/circuitbuild.c +++ b/src/or/circuitbuild.c @@ -919,9 +919,18 @@ 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/command.c b/src/or/command.c index 5866c386e4..cebb5bfc7a 100644 --- a/src/or/command.c +++ b/src/or/command.c @@ -328,8 +328,16 @@ command_process_create_cell(cell_t *cell, channel_t *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)) + 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 (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); @@ -344,9 +352,15 @@ command_process_create_cell(cell_t *cell, channel_t *chan) int len; created_cell_t created_cell; - /* Make sure we never try to use the OR connection on which we - * received this cell to satisfy an EXTEND request, */ - channel_mark_client(chan); + /* If this is a create_fast, this might be a client. Let's check. */ + if (connection_or_digest_is_known_relay(chan->identity_digest)) { + // 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); + } memset(&created_cell, 0, sizeof(created_cell)); len = onion_skin_server_handshake(ONION_HANDSHAKE_TYPE_FAST, diff --git a/src/or/config.c b/src/or/config.c index a527571cb0..d7489c0a46 100644 --- a/src/or/config.c +++ b/src/or/config.c @@ -242,6 +242,7 @@ 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"), @@ -458,6 +459,8 @@ 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"), @@ -3429,6 +3432,14 @@ 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."); diff --git a/src/or/connection_or.c b/src/or/connection_or.c index cefe42c4db..40c28e60e5 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); @@ -1983,12 +1984,23 @@ 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 (conn->chan->base_.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 +2106,7 @@ 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 80a5bddb14..5d089e6789 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 4e54deca55..c52fdf1fb0 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 \ @@ -137,6 +138,7 @@ 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 5549f97998..ef4a1ffdd0 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" @@ -176,7 +177,7 @@ 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; @@ -1119,6 +1120,8 @@ 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); } } @@ -1184,6 +1187,7 @@ CALLBACK(check_dns_honesty); CALLBACK(write_bridge_ns); CALLBACK(check_fw_helper_app); CALLBACK(heartbeat); +CALLBACK(reset_padding_counts); #undef CALLBACK @@ -1215,6 +1219,7 @@ static periodic_event_item_t periodic_events[] = { CALLBACK(write_bridge_ns), CALLBACK(check_fw_helper_app), CALLBACK(heartbeat), + CALLBACK(reset_padding_counts), END_OF_PERIODIC_EVENTS }; #undef CALLBACK @@ -1724,6 +1729,17 @@ write_stats_file_callback(time_t now, const or_options_t *options) * Periodic callback: Write bridge statistics to disk if appropriate. */ 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; +} + +static int record_bridge_stats_callback(time_t now, const or_options_t *options) { static int should_init_bridge_stats = 1; @@ -2336,6 +2352,8 @@ 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. */ @@ -3196,6 +3214,9 @@ 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 508cf6c5b6..76b968a8c8 100644 --- a/src/or/networkstatus.c +++ b/src/or/networkstatus.c @@ -72,11 +72,11 @@ 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. */ diff --git a/src/or/or.h b/src/or/or.h index 0db9f23604..02c43a5eac 100644 --- a/src/or/or.h +++ b/src/or/or.h @@ -875,6 +875,7 @@ 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 @@ -3756,6 +3757,15 @@ 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; @@ -4163,6 +4173,9 @@ 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; diff --git a/src/or/relay.c b/src/or/relay.c index 2e76a8ec36..18b68fff50 100644 --- a/src/or/relay.c +++ b/src/or/relay.c @@ -74,6 +74,7 @@ #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, @@ -196,6 +197,82 @@ 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 (!or_circ->p_chan->is_client || + (or_circ->p_chan->is_client && 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). @@ -229,6 +306,8 @@ 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; @@ -632,6 +711,9 @@ 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) @@ -1513,6 +1595,7 @@ 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 8bcd7396aa..a87ae9ef17 100644 --- a/src/or/rephist.c +++ b/src/or/rephist.c @@ -85,6 +85,9 @@ #include "routerlist.h" #include "ht.h" +#include "channelpadding.h" +#include "connection_or.h" + static void bw_arrays_init(void); static void predicted_ports_init(void); @@ -165,6 +168,44 @@ 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; @@ -1828,6 +1869,7 @@ rep_hist_get_predicted_ports(time_t now) int predicted_circs_relevance_time; smartlist_t *out = smartlist_new(); tor_assert(predicted_ports_list); + // XXX: Change this if ReducedConnectionPadding is set. predicted_circs_relevance_time = get_options()->PredictedPortsRelevanceTime; /* clean out obsolete entries */ @@ -3210,8 +3252,7 @@ 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 +3261,7 @@ 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 +3269,165 @@ 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 ff4810a56d..4d95bff0d0 100644 --- a/src/or/rephist.h +++ b/src/or/rephist.h @@ -119,5 +119,30 @@ 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 e4fa72a283..82f963a3f7 100644 --- a/src/or/router.c +++ b/src/or/router.c @@ -3199,6 +3199,12 @@ 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(); |