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tor/src/or/relay.c

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/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2013, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file relay.c
* \brief Handle relay cell encryption/decryption, plus packaging and
* receiving from circuits, plus queuing on circuits.
**/
#define RELAY_PRIVATE
#include "or.h"
#include "addressmap.h"
#include "buffers.h"
#include "channel.h"
#include "circuitbuild.h"
#include "circuitlist.h"
#include "circuituse.h"
#include "config.h"
#include "connection.h"
#include "connection_edge.h"
#include "connection_or.h"
#include "control.h"
#include "geoip.h"
#include "main.h"
#include "mempool.h"
#include "networkstatus.h"
#include "nodelist.h"
#include "onion.h"
#include "policies.h"
#include "reasons.h"
#include "relay.h"
#include "rendcommon.h"
#include "router.h"
#include "routerlist.h"
#include "routerparse.h"
static edge_connection_t *relay_lookup_conn(circuit_t *circ, cell_t *cell,
cell_direction_t cell_direction,
crypt_path_t *layer_hint);
static int connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
edge_connection_t *conn,
crypt_path_t *layer_hint);
static void circuit_consider_sending_sendme(circuit_t *circ,
crypt_path_t *layer_hint);
static void circuit_resume_edge_reading(circuit_t *circ,
crypt_path_t *layer_hint);
static int circuit_resume_edge_reading_helper(edge_connection_t *conn,
circuit_t *circ,
crypt_path_t *layer_hint);
static int circuit_consider_stop_edge_reading(circuit_t *circ,
crypt_path_t *layer_hint);
static int circuit_queue_streams_are_blocked(circuit_t *circ);
static void adjust_exit_policy_from_exitpolicy_failure(origin_circuit_t *circ,
entry_connection_t *conn,
node_t *node,
const tor_addr_t *addr);
/** Stop reading on edge connections when we have this many cells
* waiting on the appropriate queue. */
#define CELL_QUEUE_HIGHWATER_SIZE 256
/** Start reading from edge connections again when we get down to this many
* cells. */
#define CELL_QUEUE_LOWWATER_SIZE 64
/** Stats: how many relay cells have originated at this hop, or have
* been relayed onward (not recognized at this hop)?
*/
uint64_t stats_n_relay_cells_relayed = 0;
/** Stats: how many relay cells have been delivered to streams at this
* hop?
*/
uint64_t stats_n_relay_cells_delivered = 0;
/** Used to tell which stream to read from first on a circuit. */
static tor_weak_rng_t stream_choice_rng = TOR_WEAK_RNG_INIT;
/** Update digest from the payload of cell. Assign integrity part to
* cell.
*/
static void
relay_set_digest(crypto_digest_t *digest, cell_t *cell)
{
char integrity[4];
relay_header_t rh;
crypto_digest_add_bytes(digest, (char*)cell->payload, CELL_PAYLOAD_SIZE);
crypto_digest_get_digest(digest, integrity, 4);
// log_fn(LOG_DEBUG,"Putting digest of %u %u %u %u into relay cell.",
// integrity[0], integrity[1], integrity[2], integrity[3]);
relay_header_unpack(&rh, cell->payload);
memcpy(rh.integrity, integrity, 4);
relay_header_pack(cell->payload, &rh);
}
/** Does the digest for this circuit indicate that this cell is for us?
*
* Update digest from the payload of cell (with the integrity part set
* to 0). If the integrity part is valid, return 1, else restore digest
* and cell to their original state and return 0.
*/
static int
relay_digest_matches(crypto_digest_t *digest, cell_t *cell)
{
char received_integrity[4], calculated_integrity[4];
relay_header_t rh;
crypto_digest_t *backup_digest=NULL;
backup_digest = crypto_digest_dup(digest);
relay_header_unpack(&rh, cell->payload);
memcpy(received_integrity, rh.integrity, 4);
memset(rh.integrity, 0, 4);
relay_header_pack(cell->payload, &rh);
// log_fn(LOG_DEBUG,"Reading digest of %u %u %u %u from relay cell.",
// received_integrity[0], received_integrity[1],
// received_integrity[2], received_integrity[3]);
crypto_digest_add_bytes(digest, (char*) cell->payload, CELL_PAYLOAD_SIZE);
crypto_digest_get_digest(digest, calculated_integrity, 4);
if (tor_memneq(received_integrity, calculated_integrity, 4)) {
// log_fn(LOG_INFO,"Recognized=0 but bad digest. Not recognizing.");
// (%d vs %d).", received_integrity, calculated_integrity);
/* restore digest to its old form */
crypto_digest_assign(digest, backup_digest);
/* restore the relay header */
memcpy(rh.integrity, received_integrity, 4);
relay_header_pack(cell->payload, &rh);
crypto_digest_free(backup_digest);
return 0;
}
crypto_digest_free(backup_digest);
return 1;
}
/** Apply <b>cipher</b> to CELL_PAYLOAD_SIZE bytes of <b>in</b>
* (in place).
*
* If <b>encrypt_mode</b> is 1 then encrypt, else decrypt.
*
* Return -1 if the crypto fails, else return 0.
*/
static int
relay_crypt_one_payload(crypto_cipher_t *cipher, uint8_t *in,
int encrypt_mode)
{
int r;
(void)encrypt_mode;
r = crypto_cipher_crypt_inplace(cipher, (char*) in, CELL_PAYLOAD_SIZE);
if (r) {
log_warn(LD_BUG,"Error during relay encryption");
return -1;
}
return 0;
}
/** 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).
* - Check if recognized (if exitward).
* - If recognized and the digest checks out, then find if there's a stream
* that the cell is intended for, and deliver it to the right
* connection_edge.
* - If not recognized, then we need to relay it: append it to the appropriate
* cell_queue on <b>circ</b>.
*
* Return -<b>reason</b> on failure.
*/
int
circuit_receive_relay_cell(cell_t *cell, circuit_t *circ,
cell_direction_t cell_direction)
{
channel_t *chan = NULL;
crypt_path_t *layer_hint=NULL;
char recognized=0;
int reason;
tor_assert(cell);
tor_assert(circ);
tor_assert(cell_direction == CELL_DIRECTION_OUT ||
cell_direction == CELL_DIRECTION_IN);
if (circ->marked_for_close)
return 0;
if (relay_crypt(circ, cell, cell_direction, &layer_hint, &recognized) < 0) {
log_warn(LD_BUG,"relay crypt failed. Dropping connection.");
return -END_CIRC_REASON_INTERNAL;
}
if (recognized) {
edge_connection_t *conn = NULL;
if (circ->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING) {
pathbias_check_probe_response(circ, cell);
/* We need to drop this cell no matter what to avoid code that expects
* a certain purpose (such as the hidserv code). */
return 0;
}
conn = relay_lookup_conn(circ, cell, cell_direction,
layer_hint);
if (cell_direction == CELL_DIRECTION_OUT) {
++stats_n_relay_cells_delivered;
log_debug(LD_OR,"Sending away from origin.");
if ((reason=connection_edge_process_relay_cell(cell, circ, conn, NULL))
< 0) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"connection_edge_process_relay_cell (away from origin) "
"failed.");
return reason;
}
}
if (cell_direction == CELL_DIRECTION_IN) {
++stats_n_relay_cells_delivered;
log_debug(LD_OR,"Sending to origin.");
if ((reason = connection_edge_process_relay_cell(cell, circ, conn,
layer_hint)) < 0) {
log_warn(LD_OR,
"connection_edge_process_relay_cell (at origin) failed.");
return reason;
}
}
return 0;
}
/* not recognized. pass it on. */
if (cell_direction == CELL_DIRECTION_OUT) {
cell->circ_id = circ->n_circ_id; /* switch it */
chan = circ->n_chan;
} else if (! CIRCUIT_IS_ORIGIN(circ)) {
cell->circ_id = TO_OR_CIRCUIT(circ)->p_circ_id; /* switch it */
chan = TO_OR_CIRCUIT(circ)->p_chan;
} else {
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Dropping unrecognized inbound cell on origin circuit.");
/* If we see unrecognized cells on path bias testing circs,
* it's bad mojo. Those circuits need to die.
* XXX: Shouldn't they always die? */
if (circ->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING) {
TO_ORIGIN_CIRCUIT(circ)->path_state = PATH_STATE_USE_FAILED;
return -END_CIRC_REASON_TORPROTOCOL;
} else {
return 0;
}
}
if (!chan) {
// XXXX Can this splice stuff be done more cleanly?
if (! CIRCUIT_IS_ORIGIN(circ) &&
TO_OR_CIRCUIT(circ)->rend_splice &&
cell_direction == CELL_DIRECTION_OUT) {
or_circuit_t *splice = TO_OR_CIRCUIT(circ)->rend_splice;
tor_assert(circ->purpose == CIRCUIT_PURPOSE_REND_ESTABLISHED);
tor_assert(splice->base_.purpose == CIRCUIT_PURPOSE_REND_ESTABLISHED);
cell->circ_id = splice->p_circ_id;
cell->command = CELL_RELAY; /* can't be relay_early anyway */
if ((reason = circuit_receive_relay_cell(cell, TO_CIRCUIT(splice),
CELL_DIRECTION_IN)) < 0) {
log_warn(LD_REND, "Error relaying cell across rendezvous; closing "
"circuits");
/* XXXX Do this here, or just return -1? */
circuit_mark_for_close(circ, -reason);
return reason;
}
return 0;
}
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Didn't recognize cell, but circ stops here! Closing circ.");
return -END_CIRC_REASON_TORPROTOCOL;
}
log_debug(LD_OR,"Passing on unrecognized cell.");
++stats_n_relay_cells_relayed; /* XXXX no longer quite accurate {cells}
* we might kill the circ before we relay
* the cells. */
append_cell_to_circuit_queue(circ, chan, cell, cell_direction, 0);
return 0;
}
/** Do the appropriate en/decryptions for <b>cell</b> arriving on
* <b>circ</b> in direction <b>cell_direction</b>.
*
* If cell_direction == CELL_DIRECTION_IN:
* - If we're at the origin (we're the OP), for hops 1..N,
* decrypt cell. If recognized, stop.
* - Else (we're not the OP), encrypt one hop. Cell is not recognized.
*
* If cell_direction == CELL_DIRECTION_OUT:
* - decrypt one hop. Check if recognized.
*
* If cell is recognized, set *recognized to 1, and set
* *layer_hint to the hop that recognized it.
*
* Return -1 to indicate that we should mark the circuit for close,
* else return 0.
*/
int
relay_crypt(circuit_t *circ, cell_t *cell, cell_direction_t cell_direction,
crypt_path_t **layer_hint, char *recognized)
{
relay_header_t rh;
tor_assert(circ);
tor_assert(cell);
tor_assert(recognized);
tor_assert(cell_direction == CELL_DIRECTION_IN ||
cell_direction == CELL_DIRECTION_OUT);
if (cell_direction == CELL_DIRECTION_IN) {
if (CIRCUIT_IS_ORIGIN(circ)) { /* We're at the beginning of the circuit.
* We'll want to do layered decrypts. */
crypt_path_t *thishop, *cpath = TO_ORIGIN_CIRCUIT(circ)->cpath;
thishop = cpath;
if (thishop->state != CPATH_STATE_OPEN) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Relay cell before first created cell? Closing.");
return -1;
}
do { /* Remember: cpath is in forward order, that is, first hop first. */
tor_assert(thishop);
if (relay_crypt_one_payload(thishop->b_crypto, cell->payload, 0) < 0)
return -1;
relay_header_unpack(&rh, cell->payload);
if (rh.recognized == 0) {
/* it's possibly recognized. have to check digest to be sure. */
if (relay_digest_matches(thishop->b_digest, cell)) {
*recognized = 1;
*layer_hint = thishop;
return 0;
}
}
thishop = thishop->next;
} while (thishop != cpath && thishop->state == CPATH_STATE_OPEN);
log_fn(LOG_PROTOCOL_WARN, LD_OR,
"Incoming cell at client not recognized. Closing.");
return -1;
} else { /* we're in the middle. Just one crypt. */
if (relay_crypt_one_payload(TO_OR_CIRCUIT(circ)->p_crypto,
cell->payload, 1) < 0)
return -1;
// log_fn(LOG_DEBUG,"Skipping recognized check, because we're not "
// "the client.");
}
} else /* cell_direction == CELL_DIRECTION_OUT */ {
/* we're in the middle. Just one crypt. */
if (relay_crypt_one_payload(TO_OR_CIRCUIT(circ)->n_crypto,
cell->payload, 0) < 0)
return -1;
relay_header_unpack(&rh, cell->payload);
if (rh.recognized == 0) {
/* it's possibly recognized. have to check digest to be sure. */
if (relay_digest_matches(TO_OR_CIRCUIT(circ)->n_digest, cell)) {
*recognized = 1;
return 0;
}
}
}
return 0;
}
/** Package a relay cell from an edge:
* - Encrypt it to the right layer
* - Append it to the appropriate cell_queue on <b>circ</b>.
*/
static int
circuit_package_relay_cell(cell_t *cell, circuit_t *circ,
cell_direction_t cell_direction,
crypt_path_t *layer_hint, streamid_t on_stream)
{
channel_t *chan; /* where to send the cell */
if (cell_direction == CELL_DIRECTION_OUT) {
crypt_path_t *thishop; /* counter for repeated crypts */
chan = circ->n_chan;
if (!CIRCUIT_IS_ORIGIN(circ) || !chan) {
log_warn(LD_BUG,"outgoing relay cell has n_chan==NULL. Dropping.");
return 0; /* just drop it */
}
relay_set_digest(layer_hint->f_digest, cell);
thishop = layer_hint;
/* moving from farthest to nearest hop */
do {
tor_assert(thishop);
/* XXXX RD This is a bug, right? */
log_debug(LD_OR,"crypting a layer of the relay cell.");
if (relay_crypt_one_payload(thishop->f_crypto, cell->payload, 1) < 0) {
return -1;
}
thishop = thishop->prev;
} while (thishop != TO_ORIGIN_CIRCUIT(circ)->cpath->prev);
} else { /* incoming cell */
or_circuit_t *or_circ;
if (CIRCUIT_IS_ORIGIN(circ)) {
/* We should never package an _incoming_ cell from the circuit
* origin; that means we messed up somewhere. */
log_warn(LD_BUG,"incoming relay cell at origin circuit. Dropping.");
assert_circuit_ok(circ);
return 0; /* just drop it */
}
or_circ = TO_OR_CIRCUIT(circ);
chan = or_circ->p_chan;
relay_set_digest(or_circ->p_digest, cell);
if (relay_crypt_one_payload(or_circ->p_crypto, cell->payload, 1) < 0)
return -1;
}
++stats_n_relay_cells_relayed;
append_cell_to_circuit_queue(circ, chan, cell, cell_direction, on_stream);
return 0;
}
/** If cell's stream_id matches the stream_id of any conn that's
* attached to circ, return that conn, else return NULL.
*/
static edge_connection_t *
relay_lookup_conn(circuit_t *circ, cell_t *cell,
cell_direction_t cell_direction, crypt_path_t *layer_hint)
{
edge_connection_t *tmpconn;
relay_header_t rh;
relay_header_unpack(&rh, cell->payload);
if (!rh.stream_id)
return NULL;
/* IN or OUT cells could have come from either direction, now
* that we allow rendezvous *to* an OP.
*/
if (CIRCUIT_IS_ORIGIN(circ)) {
for (tmpconn = TO_ORIGIN_CIRCUIT(circ)->p_streams; tmpconn;
tmpconn=tmpconn->next_stream) {
if (rh.stream_id == tmpconn->stream_id &&
!tmpconn->base_.marked_for_close &&
tmpconn->cpath_layer == layer_hint) {
log_debug(LD_APP,"found conn for stream %d.", rh.stream_id);
return tmpconn;
}
}
} else {
for (tmpconn = TO_OR_CIRCUIT(circ)->n_streams; tmpconn;
tmpconn=tmpconn->next_stream) {
if (rh.stream_id == tmpconn->stream_id &&
!tmpconn->base_.marked_for_close) {
log_debug(LD_EXIT,"found conn for stream %d.", rh.stream_id);
if (cell_direction == CELL_DIRECTION_OUT ||
connection_edge_is_rendezvous_stream(tmpconn))
return tmpconn;
}
}
for (tmpconn = TO_OR_CIRCUIT(circ)->resolving_streams; tmpconn;
tmpconn=tmpconn->next_stream) {
if (rh.stream_id == tmpconn->stream_id &&
!tmpconn->base_.marked_for_close) {
log_debug(LD_EXIT,"found conn for stream %d.", rh.stream_id);
return tmpconn;
}
}
}
return NULL; /* probably a begin relay cell */
}
/** Pack the relay_header_t host-order structure <b>src</b> into
* network-order in the buffer <b>dest</b>. See tor-spec.txt for details
* about the wire format.
*/
void
relay_header_pack(uint8_t *dest, const relay_header_t *src)
{
set_uint8(dest, src->command);
set_uint16(dest+1, htons(src->recognized));
set_uint16(dest+3, htons(src->stream_id));
memcpy(dest+5, src->integrity, 4);
set_uint16(dest+9, htons(src->length));
}
/** Unpack the network-order buffer <b>src</b> into a host-order
* relay_header_t structure <b>dest</b>.
*/
void
relay_header_unpack(relay_header_t *dest, const uint8_t *src)
{
dest->command = get_uint8(src);
dest->recognized = ntohs(get_uint16(src+1));
dest->stream_id = ntohs(get_uint16(src+3));
memcpy(dest->integrity, src+5, 4);
dest->length = ntohs(get_uint16(src+9));
}
/** Convert the relay <b>command</b> into a human-readable string. */
static const char *
relay_command_to_string(uint8_t command)
{
switch (command) {
case RELAY_COMMAND_BEGIN: return "BEGIN";
case RELAY_COMMAND_DATA: return "DATA";
case RELAY_COMMAND_END: return "END";
case RELAY_COMMAND_CONNECTED: return "CONNECTED";
case RELAY_COMMAND_SENDME: return "SENDME";
case RELAY_COMMAND_EXTEND: return "EXTEND";
case RELAY_COMMAND_EXTENDED: return "EXTENDED";
case RELAY_COMMAND_TRUNCATE: return "TRUNCATE";
case RELAY_COMMAND_TRUNCATED: return "TRUNCATED";
case RELAY_COMMAND_DROP: return "DROP";
case RELAY_COMMAND_RESOLVE: return "RESOLVE";
case RELAY_COMMAND_RESOLVED: return "RESOLVED";
case RELAY_COMMAND_BEGIN_DIR: return "BEGIN_DIR";
case RELAY_COMMAND_ESTABLISH_INTRO: return "ESTABLISH_INTRO";
case RELAY_COMMAND_ESTABLISH_RENDEZVOUS: return "ESTABLISH_RENDEZVOUS";
case RELAY_COMMAND_INTRODUCE1: return "INTRODUCE1";
case RELAY_COMMAND_INTRODUCE2: return "INTRODUCE2";
case RELAY_COMMAND_RENDEZVOUS1: return "RENDEZVOUS1";
case RELAY_COMMAND_RENDEZVOUS2: return "RENDEZVOUS2";
case RELAY_COMMAND_INTRO_ESTABLISHED: return "INTRO_ESTABLISHED";
case RELAY_COMMAND_RENDEZVOUS_ESTABLISHED:
return "RENDEZVOUS_ESTABLISHED";
case RELAY_COMMAND_INTRODUCE_ACK: return "INTRODUCE_ACK";
default: return "(unrecognized)";
}
}
/** Make a relay cell out of <b>relay_command</b> and <b>payload</b>, and send
* it onto the open circuit <b>circ</b>. <b>stream_id</b> is the ID on
* <b>circ</b> for the stream that's sending the relay cell, or 0 if it's a
* control cell. <b>cpath_layer</b> is NULL for OR->OP cells, or the
* destination hop for OP->OR cells.
*
* If you can't send the cell, mark the circuit for close and return -1. Else
* return 0.
*/
int
relay_send_command_from_edge(streamid_t stream_id, circuit_t *circ,
uint8_t relay_command, const char *payload,
size_t payload_len, crypt_path_t *cpath_layer)
{
cell_t cell;
relay_header_t rh;
cell_direction_t cell_direction;
/* XXXX NM Split this function into a separate versions per circuit type? */
tor_assert(circ);
tor_assert(payload_len <= RELAY_PAYLOAD_SIZE);
memset(&cell, 0, sizeof(cell_t));
cell.command = CELL_RELAY;
if (cpath_layer) {
cell.circ_id = circ->n_circ_id;
cell_direction = CELL_DIRECTION_OUT;
} else if (! CIRCUIT_IS_ORIGIN(circ)) {
cell.circ_id = TO_OR_CIRCUIT(circ)->p_circ_id;
cell_direction = CELL_DIRECTION_IN;
} else {
return -1;
}
memset(&rh, 0, sizeof(rh));
rh.command = relay_command;
rh.stream_id = stream_id;
rh.length = payload_len;
relay_header_pack(cell.payload, &rh);
if (payload_len)
memcpy(cell.payload+RELAY_HEADER_SIZE, payload, payload_len);
log_debug(LD_OR,"delivering %d cell %s.", relay_command,
cell_direction == CELL_DIRECTION_OUT ? "forward" : "backward");
/* 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)
geoip_change_dirreq_state(circ->dirreq_id, DIRREQ_TUNNELED,
DIRREQ_END_CELL_SENT);
if (cell_direction == CELL_DIRECTION_OUT && circ->n_chan) {
/* if we're using relaybandwidthrate, this conn wants priority */
channel_timestamp_client(circ->n_chan);
}
if (cell_direction == CELL_DIRECTION_OUT) {
origin_circuit_t *origin_circ = TO_ORIGIN_CIRCUIT(circ);
if (origin_circ->remaining_relay_early_cells > 0 &&
(relay_command == RELAY_COMMAND_EXTEND ||
relay_command == RELAY_COMMAND_EXTEND2 ||
cpath_layer != origin_circ->cpath)) {
/* If we've got any relay_early cells left and (we're sending
* an extend cell or we're not talking to the first hop), use
* one of them. Don't worry about the conn protocol version:
* append_cell_to_circuit_queue will fix it up. */
cell.command = CELL_RELAY_EARLY;
--origin_circ->remaining_relay_early_cells;
log_debug(LD_OR, "Sending a RELAY_EARLY cell; %d remaining.",
(int)origin_circ->remaining_relay_early_cells);
/* Memorize the command that is sent as RELAY_EARLY cell; helps debug
* task 878. */
origin_circ->relay_early_commands[
origin_circ->relay_early_cells_sent++] = relay_command;
} else if (relay_command == RELAY_COMMAND_EXTEND ||
relay_command == RELAY_COMMAND_EXTEND2) {
/* If no RELAY_EARLY cells can be sent over this circuit, log which
* commands have been sent as RELAY_EARLY cells before; helps debug
* task 878. */
smartlist_t *commands_list = smartlist_new();
int i = 0;
char *commands = NULL;
for (; i < origin_circ->relay_early_cells_sent; i++)
smartlist_add(commands_list, (char *)
relay_command_to_string(origin_circ->relay_early_commands[i]));
commands = smartlist_join_strings(commands_list, ",", 0, NULL);
log_warn(LD_BUG, "Uh-oh. We're sending a RELAY_COMMAND_EXTEND cell, "
"but we have run out of RELAY_EARLY cells on that circuit. "
"Commands sent before: %s", commands);
tor_free(commands);
smartlist_free(commands_list);
}
}
if (circuit_package_relay_cell(&cell, circ, cell_direction, cpath_layer,
stream_id) < 0) {
log_warn(LD_BUG,"circuit_package_relay_cell failed. Closing.");
circuit_mark_for_close(circ, END_CIRC_REASON_INTERNAL);
return -1;
}
return 0;
}
/** Make a relay cell out of <b>relay_command</b> and <b>payload</b>, and
* send it onto the open circuit <b>circ</b>. <b>fromconn</b> is the stream
* that's sending the relay cell, or NULL if it's a control cell.
* <b>cpath_layer</b> is NULL for OR->OP cells, or the destination hop
* for OP->OR cells.
*
* If you can't send the cell, mark the circuit for close and
* return -1. Else return 0.
*/
int
connection_edge_send_command(edge_connection_t *fromconn,
uint8_t relay_command, const char *payload,
size_t payload_len)
{
/* XXXX NM Split this function into a separate versions per circuit type? */
circuit_t *circ;
crypt_path_t *cpath_layer = fromconn->cpath_layer;
tor_assert(fromconn);
circ = fromconn->on_circuit;
if (fromconn->base_.marked_for_close) {
log_warn(LD_BUG,
"called on conn that's already marked for close at %s:%d.",
fromconn->base_.marked_for_close_file,
fromconn->base_.marked_for_close);
return 0;
}
if (!circ) {
if (fromconn->base_.type == CONN_TYPE_AP) {
log_info(LD_APP,"no circ. Closing conn.");
connection_mark_unattached_ap(EDGE_TO_ENTRY_CONN(fromconn),
END_STREAM_REASON_INTERNAL);
} else {
log_info(LD_EXIT,"no circ. Closing conn.");
fromconn->edge_has_sent_end = 1; /* no circ to send to */
fromconn->end_reason = END_STREAM_REASON_INTERNAL;
connection_mark_for_close(TO_CONN(fromconn));
}
return -1;
}
return relay_send_command_from_edge(fromconn->stream_id, circ,
relay_command, payload,
payload_len, cpath_layer);
}
/** How many times will I retry a stream that fails due to DNS
* resolve failure or misc error?
*/
#define MAX_RESOLVE_FAILURES 3
/** Return 1 if reason is something that you should retry if you
* get the end cell before you've connected; else return 0. */
static int
edge_reason_is_retriable(int reason)
{
return reason == END_STREAM_REASON_HIBERNATING ||
reason == END_STREAM_REASON_RESOURCELIMIT ||
reason == END_STREAM_REASON_EXITPOLICY ||
reason == END_STREAM_REASON_RESOLVEFAILED ||
reason == END_STREAM_REASON_MISC ||
reason == END_STREAM_REASON_NOROUTE;
}
/** Called when we receive an END cell on a stream that isn't open yet,
* from the client side.
* Arguments are as for connection_edge_process_relay_cell().
*/
static int
connection_ap_process_end_not_open(
relay_header_t *rh, cell_t *cell, origin_circuit_t *circ,
entry_connection_t *conn, crypt_path_t *layer_hint)
{
node_t *exitrouter;
int reason = *(cell->payload+RELAY_HEADER_SIZE);
int control_reason;
edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(conn);
(void) layer_hint; /* unused */
if (rh->length > 0) {
if (reason == END_STREAM_REASON_TORPROTOCOL ||
reason == END_STREAM_REASON_INTERNAL ||
reason == END_STREAM_REASON_DESTROY) {
/* All three of these reasons could mean a failed tag
* hit the exit and it complained. Do not probe.
* Fail the circuit. */
circ->path_state = PATH_STATE_USE_FAILED;
return -END_CIRC_REASON_TORPROTOCOL;
} else {
/* Path bias: If we get a valid reason code from the exit,
* it wasn't due to tagging.
*
* We rely on recognized+digest being strong enough to make
* tags unlikely to allow us to get tagged, yet 'recognized'
* reason codes here. */
pathbias_mark_use_success(circ);
}
}
if (rh->length == 0) {
reason = END_STREAM_REASON_MISC;
}
control_reason = reason | END_STREAM_REASON_FLAG_REMOTE;
if (edge_reason_is_retriable(reason) &&
/* avoid retry if rend */
!connection_edge_is_rendezvous_stream(edge_conn)) {
const char *chosen_exit_digest =
circ->build_state->chosen_exit->identity_digest;
log_info(LD_APP,"Address '%s' refused due to '%s'. Considering retrying.",
safe_str(conn->socks_request->address),
stream_end_reason_to_string(reason));
exitrouter = node_get_mutable_by_id(chosen_exit_digest);
switch (reason) {
case END_STREAM_REASON_EXITPOLICY: {
tor_addr_t addr;
tor_addr_make_unspec(&addr);
if (rh->length >= 5) {
int ttl = -1;
tor_addr_make_unspec(&addr);
if (rh->length == 5 || rh->length == 9) {
tor_addr_from_ipv4n(&addr,
get_uint32(cell->payload+RELAY_HEADER_SIZE+1));
if (rh->length == 9)
ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+5));
} else if (rh->length == 17 || rh->length == 21) {
tor_addr_from_ipv6_bytes(&addr,
(char*)(cell->payload+RELAY_HEADER_SIZE+1));
if (rh->length == 21)
ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+17));
}
if (tor_addr_is_null(&addr)) {
log_info(LD_APP,"Address '%s' resolved to 0.0.0.0. Closing,",
safe_str(conn->socks_request->address));
connection_mark_unattached_ap(conn, END_STREAM_REASON_TORPROTOCOL);
return 0;
}
if ((tor_addr_family(&addr) == AF_INET && !conn->ipv4_traffic_ok) ||
(tor_addr_family(&addr) == AF_INET6 && !conn->ipv6_traffic_ok)) {
log_fn(LOG_PROTOCOL_WARN, LD_APP,
"Got an EXITPOLICY failure on a connection with a "
"mismatched family. Closing.");
connection_mark_unattached_ap(conn, END_STREAM_REASON_TORPROTOCOL);
return 0;
}
if (get_options()->ClientDNSRejectInternalAddresses &&
tor_addr_is_internal(&addr, 0)) {
log_info(LD_APP,"Address '%s' resolved to internal. Closing,",
safe_str(conn->socks_request->address));
connection_mark_unattached_ap(conn, END_STREAM_REASON_TORPROTOCOL);
return 0;
}
client_dns_set_addressmap(conn,
conn->socks_request->address, &addr,
conn->chosen_exit_name, ttl);
{
char new_addr[TOR_ADDR_BUF_LEN];
tor_addr_to_str(new_addr, &addr, sizeof(new_addr), 1);
if (strcmp(conn->socks_request->address, new_addr)) {
strlcpy(conn->socks_request->address, new_addr,
sizeof(conn->socks_request->address));
control_event_stream_status(conn, STREAM_EVENT_REMAP, 0);
}
}
}
/* check if he *ought* to have allowed it */
adjust_exit_policy_from_exitpolicy_failure(circ,
conn,
exitrouter,
&addr);
if (conn->chosen_exit_optional ||
conn->chosen_exit_retries) {
/* stop wanting a specific exit */
conn->chosen_exit_optional = 0;
/* A non-zero chosen_exit_retries can happen if we set a
* TrackHostExits for this address under a port that the exit
* relay allows, but then try the same address with a different
* port that it doesn't allow to exit. We shouldn't unregister
* the mapping, since it is probably still wanted on the
* original port. But now we give away to the exit relay that
* we probably have a TrackHostExits on it. So be it. */
conn->chosen_exit_retries = 0;
tor_free(conn->chosen_exit_name); /* clears it */
}
if (connection_ap_detach_retriable(conn, circ, control_reason) >= 0)
return 0;
/* else, conn will get closed below */
break;
}
case END_STREAM_REASON_CONNECTREFUSED:
if (!conn->chosen_exit_optional)
break; /* break means it'll close, below */
/* Else fall through: expire this circuit, clear the
* chosen_exit_name field, and try again. */
case END_STREAM_REASON_RESOLVEFAILED:
case END_STREAM_REASON_TIMEOUT:
case END_STREAM_REASON_MISC:
case END_STREAM_REASON_NOROUTE:
if (client_dns_incr_failures(conn->socks_request->address)
< MAX_RESOLVE_FAILURES) {
/* We haven't retried too many times; reattach the connection. */
circuit_log_path(LOG_INFO,LD_APP,circ);
/* Mark this circuit "unusable for new streams". */
mark_circuit_unusable_for_new_conns(circ);
if (conn->chosen_exit_optional) {
/* stop wanting a specific exit */
conn->chosen_exit_optional = 0;
tor_free(conn->chosen_exit_name); /* clears it */
}
if (connection_ap_detach_retriable(conn, circ, control_reason) >= 0)
return 0;
/* else, conn will get closed below */
} else {
log_notice(LD_APP,
"Have tried resolving or connecting to address '%s' "
"at %d different places. Giving up.",
safe_str(conn->socks_request->address),
MAX_RESOLVE_FAILURES);
/* clear the failures, so it will have a full try next time */
client_dns_clear_failures(conn->socks_request->address);
}
break;
case END_STREAM_REASON_HIBERNATING:
case END_STREAM_REASON_RESOURCELIMIT:
if (exitrouter) {
policies_set_node_exitpolicy_to_reject_all(exitrouter);
}
if (conn->chosen_exit_optional) {
/* stop wanting a specific exit */
conn->chosen_exit_optional = 0;
tor_free(conn->chosen_exit_name); /* clears it */
}
if (connection_ap_detach_retriable(conn, circ, control_reason) >= 0)
return 0;
/* else, will close below */
break;
} /* end switch */
log_info(LD_APP,"Giving up on retrying; conn can't be handled.");
}
log_info(LD_APP,
"Edge got end (%s) before we're connected. Marking for close.",
stream_end_reason_to_string(rh->length > 0 ? reason : -1));
circuit_log_path(LOG_INFO,LD_APP,circ);
/* need to test because of detach_retriable */
if (!ENTRY_TO_CONN(conn)->marked_for_close)
connection_mark_unattached_ap(conn, control_reason);
return 0;
}
/** Called when we have gotten an END_REASON_EXITPOLICY failure on <b>circ</b>
* for <b>conn</b>, while attempting to connect via <b>node</b>. If the node
* told us which address it rejected, then <b>addr</b> is that address;
* otherwise it is AF_UNSPEC.
*
* If we are sure the node should have allowed this address, mark the node as
* having a reject *:* exit policy. Otherwise, mark the circuit as unusable
* for this particular address.
**/
static void
adjust_exit_policy_from_exitpolicy_failure(origin_circuit_t *circ,
entry_connection_t *conn,
node_t *node,
const tor_addr_t *addr)
{
int make_reject_all = 0;
const sa_family_t family = tor_addr_family(addr);
if (node) {
tor_addr_t tmp;
int asked_for_family = tor_addr_parse(&tmp, conn->socks_request->address);
if (family == AF_UNSPEC) {
make_reject_all = 1;
} else if (node_exit_policy_is_exact(node, family) &&
asked_for_family != -1 && !conn->chosen_exit_name) {
make_reject_all = 1;
}
if (make_reject_all) {
log_info(LD_APP,
"Exitrouter %s seems to be more restrictive than its exit "
"policy. Not using this router as exit for now.",
node_describe(node));
policies_set_node_exitpolicy_to_reject_all(node);
}
}
if (family != AF_UNSPEC)
addr_policy_append_reject_addr(&circ->prepend_policy, addr);
}
/** Helper: change the socks_request-&gt;address field on conn to the
* dotted-quad representation of <b>new_addr</b>,
* and send an appropriate REMAP event. */
static void
remap_event_helper(entry_connection_t *conn, const tor_addr_t *new_addr)
{
tor_addr_to_str(conn->socks_request->address, new_addr,
sizeof(conn->socks_request->address),
1);
control_event_stream_status(conn, STREAM_EVENT_REMAP,
REMAP_STREAM_SOURCE_EXIT);
}
/** Extract the contents of a connected cell in <b>cell</b>, whose relay
* header has already been parsed into <b>rh</b>. On success, set
* <b>addr_out</b> to the address we're connected to, and <b>ttl_out</b> to
* the ttl of that address, in seconds, and return 0. On failure, return
* -1. */
int
connected_cell_parse(const relay_header_t *rh, const cell_t *cell,
tor_addr_t *addr_out, int *ttl_out)
{
uint32_t bytes;
const uint8_t *payload = cell->payload + RELAY_HEADER_SIZE;
tor_addr_make_unspec(addr_out);
*ttl_out = -1;
if (rh->length == 0)
return 0;
if (rh->length < 4)
return -1;
bytes = ntohl(get_uint32(payload));
/* If bytes is 0, this is maybe a v6 address. Otherwise it's a v4 address */
if (bytes != 0) {
/* v4 address */
tor_addr_from_ipv4h(addr_out, bytes);
if (rh->length >= 8) {
bytes = ntohl(get_uint32(payload + 4));
if (bytes <= INT32_MAX)
*ttl_out = bytes;
}
} else {
if (rh->length < 25) /* 4 bytes of 0s, 1 addr, 16 ipv4, 4 ttl. */
return -1;
if (get_uint8(payload + 4) != 6)
return -1;
tor_addr_from_ipv6_bytes(addr_out, (char*)(payload + 5));
bytes = ntohl(get_uint32(payload + 21));
if (bytes <= INT32_MAX)
*ttl_out = (int) bytes;
}
return 0;
}
/** An incoming relay cell has arrived from circuit <b>circ</b> to
* stream <b>conn</b>.
*
* The arguments here are the same as in
* connection_edge_process_relay_cell() below; this function is called
* from there when <b>conn</b> is defined and not in an open state.
*/
static int
connection_edge_process_relay_cell_not_open(
relay_header_t *rh, cell_t *cell, circuit_t *circ,
edge_connection_t *conn, crypt_path_t *layer_hint)
{
if (rh->command == RELAY_COMMAND_END) {
if (CIRCUIT_IS_ORIGIN(circ) && conn->base_.type == CONN_TYPE_AP) {
return connection_ap_process_end_not_open(rh, cell,
TO_ORIGIN_CIRCUIT(circ),
EDGE_TO_ENTRY_CONN(conn),
layer_hint);
} else {
/* we just got an 'end', don't need to send one */
conn->edge_has_sent_end = 1;
conn->end_reason = *(cell->payload+RELAY_HEADER_SIZE) |
END_STREAM_REASON_FLAG_REMOTE;
connection_mark_for_close(TO_CONN(conn));
return 0;
}
}
if (conn->base_.type == CONN_TYPE_AP &&
rh->command == RELAY_COMMAND_CONNECTED) {
tor_addr_t addr;
int ttl;
entry_connection_t *entry_conn = EDGE_TO_ENTRY_CONN(conn);
tor_assert(CIRCUIT_IS_ORIGIN(circ));
if (conn->base_.state != AP_CONN_STATE_CONNECT_WAIT) {
log_fn(LOG_PROTOCOL_WARN, LD_APP,
"Got 'connected' while not in state connect_wait. Dropping.");
return 0;
}
conn->base_.state = AP_CONN_STATE_OPEN;
log_info(LD_APP,"'connected' received after %d seconds.",
(int)(time(NULL) - conn->base_.timestamp_lastread));
if (connected_cell_parse(rh, cell, &addr, &ttl) < 0) {
log_fn(LOG_PROTOCOL_WARN, LD_APP,
"Got a badly formatted connected cell. Closing.");
connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL);
connection_mark_unattached_ap(entry_conn, END_STREAM_REASON_TORPROTOCOL);
}
if (tor_addr_family(&addr) != AF_UNSPEC) {
const sa_family_t family = tor_addr_family(&addr);
if (tor_addr_is_null(&addr) ||
(get_options()->ClientDNSRejectInternalAddresses &&
tor_addr_is_internal(&addr, 0))) {
log_info(LD_APP, "...but it claims the IP address was %s. Closing.",
fmt_addr(&addr));
connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL);
connection_mark_unattached_ap(entry_conn,
END_STREAM_REASON_TORPROTOCOL);
return 0;
}
if ((family == AF_INET && ! entry_conn->ipv4_traffic_ok) ||
(family == AF_INET6 && ! entry_conn->ipv6_traffic_ok)) {
log_fn(LOG_PROTOCOL_WARN, LD_APP,
"Got a connected cell to %s with unsupported address family."
" Closing.", fmt_addr(&addr));
connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL);
connection_mark_unattached_ap(entry_conn,
END_STREAM_REASON_TORPROTOCOL);
return 0;
}
client_dns_set_addressmap(entry_conn,
entry_conn->socks_request->address, &addr,
entry_conn->chosen_exit_name, ttl);
remap_event_helper(entry_conn, &addr);
}
circuit_log_path(LOG_INFO,LD_APP,TO_ORIGIN_CIRCUIT(circ));
/* don't send a socks reply to transparent conns */
tor_assert(entry_conn->socks_request != NULL);
if (!entry_conn->socks_request->has_finished)
connection_ap_handshake_socks_reply(entry_conn, NULL, 0, 0);
/* Was it a linked dir conn? If so, a dir request just started to
* fetch something; this could be a bootstrap status milestone. */
log_debug(LD_APP, "considering");
if (TO_CONN(conn)->linked_conn &&
TO_CONN(conn)->linked_conn->type == CONN_TYPE_DIR) {
connection_t *dirconn = TO_CONN(conn)->linked_conn;
log_debug(LD_APP, "it is! %d", dirconn->purpose);
switch (dirconn->purpose) {
case DIR_PURPOSE_FETCH_CERTIFICATE:
if (consensus_is_waiting_for_certs())
control_event_bootstrap(BOOTSTRAP_STATUS_LOADING_KEYS, 0);
break;
case DIR_PURPOSE_FETCH_CONSENSUS:
control_event_bootstrap(BOOTSTRAP_STATUS_LOADING_STATUS, 0);
break;
case DIR_PURPOSE_FETCH_SERVERDESC:
control_event_bootstrap(BOOTSTRAP_STATUS_LOADING_DESCRIPTORS,
count_loading_descriptors_progress());
break;
}
}
/* This is definitely a success, so forget about any pending data we
* had sent. */
if (entry_conn->pending_optimistic_data) {
generic_buffer_free(entry_conn->pending_optimistic_data);
entry_conn->pending_optimistic_data = NULL;
}
/* handle anything that might have queued */
if (connection_edge_package_raw_inbuf(conn, 1, NULL) < 0) {
/* (We already sent an end cell if possible) */
connection_mark_for_close(TO_CONN(conn));
return 0;
}
return 0;
}
if (conn->base_.type == CONN_TYPE_AP &&
rh->command == RELAY_COMMAND_RESOLVED) {
int ttl;
int answer_len;
uint8_t answer_type;
entry_connection_t *entry_conn = EDGE_TO_ENTRY_CONN(conn);
if (conn->base_.state != AP_CONN_STATE_RESOLVE_WAIT) {
log_fn(LOG_PROTOCOL_WARN, LD_APP, "Got a 'resolved' cell while "
"not in state resolve_wait. Dropping.");
return 0;
}
tor_assert(SOCKS_COMMAND_IS_RESOLVE(entry_conn->socks_request->command));
answer_len = cell->payload[RELAY_HEADER_SIZE+1];
if (rh->length < 2 || answer_len+2>rh->length) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Dropping malformed 'resolved' cell");
connection_mark_unattached_ap(entry_conn, END_STREAM_REASON_TORPROTOCOL);
return 0;
}
answer_type = cell->payload[RELAY_HEADER_SIZE];
if (rh->length >= answer_len+6)
ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+
2+answer_len));
else
ttl = -1;
if (answer_type == RESOLVED_TYPE_IPV4 ||
answer_type == RESOLVED_TYPE_IPV6) {
tor_addr_t addr;
if (decode_address_from_payload(&addr, cell->payload+RELAY_HEADER_SIZE,
rh->length) &&
tor_addr_is_internal(&addr, 0) &&
get_options()->ClientDNSRejectInternalAddresses) {
log_info(LD_APP,"Got a resolve with answer %s. Rejecting.",
fmt_addr(&addr));
connection_ap_handshake_socks_resolved(entry_conn,
RESOLVED_TYPE_ERROR_TRANSIENT,
0, NULL, 0, TIME_MAX);
connection_mark_unattached_ap(entry_conn,
END_STREAM_REASON_TORPROTOCOL);
return 0;
}
}
connection_ap_handshake_socks_resolved(entry_conn,
answer_type,
cell->payload[RELAY_HEADER_SIZE+1], /*answer_len*/
cell->payload+RELAY_HEADER_SIZE+2, /*answer*/
ttl,
-1);
if (answer_type == RESOLVED_TYPE_IPV4 && answer_len == 4) {
tor_addr_t addr;
tor_addr_from_ipv4n(&addr,
get_uint32(cell->payload+RELAY_HEADER_SIZE+2));
remap_event_helper(entry_conn, &addr);
} else if (answer_type == RESOLVED_TYPE_IPV6 && answer_len == 16) {
tor_addr_t addr;
tor_addr_from_ipv6_bytes(&addr,
(char*)(cell->payload+RELAY_HEADER_SIZE+2));
remap_event_helper(entry_conn, &addr);
}
connection_mark_unattached_ap(entry_conn,
END_STREAM_REASON_DONE |
END_STREAM_REASON_FLAG_ALREADY_SOCKS_REPLIED);
return 0;
}
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Got an unexpected relay command %d, in state %d (%s). Dropping.",
rh->command, conn->base_.state,
conn_state_to_string(conn->base_.type, conn->base_.state));
return 0; /* for forward compatibility, don't kill the circuit */
// connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL);
// connection_mark_for_close(conn);
// return -1;
}
/** An incoming relay cell has arrived on circuit <b>circ</b>. If
* <b>conn</b> is NULL this is a control cell, else <b>cell</b> is
* destined for <b>conn</b>.
*
* If <b>layer_hint</b> is defined, then we're the origin of the
* circuit, and it specifies the hop that packaged <b>cell</b>.
*
* Return -reason if you want to warn and tear down the circuit, else 0.
*/
static int
connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
edge_connection_t *conn,
crypt_path_t *layer_hint)
{
static int num_seen=0;
relay_header_t rh;
unsigned domain = layer_hint?LD_APP:LD_EXIT;
int reason;
int optimistic_data = 0; /* Set to 1 if we receive data on a stream
* that's in the EXIT_CONN_STATE_RESOLVING
* or EXIT_CONN_STATE_CONNECTING states. */
tor_assert(cell);
tor_assert(circ);
relay_header_unpack(&rh, cell->payload);
// log_fn(LOG_DEBUG,"command %d stream %d", rh.command, rh.stream_id);
num_seen++;
log_debug(domain, "Now seen %d relay cells here (command %d, stream %d).",
num_seen, rh.command, rh.stream_id);
if (rh.length > RELAY_PAYLOAD_SIZE) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Relay cell length field too long. Closing circuit.");
return - END_CIRC_REASON_TORPROTOCOL;
}
if (rh.stream_id == 0) {
switch (rh.command) {
case RELAY_COMMAND_BEGIN:
case RELAY_COMMAND_CONNECTED:
case RELAY_COMMAND_DATA:
case RELAY_COMMAND_END:
case RELAY_COMMAND_RESOLVE:
case RELAY_COMMAND_RESOLVED:
case RELAY_COMMAND_BEGIN_DIR:
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, "Relay command %d with zero "
"stream_id. Dropping.", (int)rh.command);
return 0;
default:
;
}
}
/* either conn is NULL, in which case we've got a control cell, or else
* conn points to the recognized stream. */
if (conn && !connection_state_is_open(TO_CONN(conn))) {
if (conn->base_.type == CONN_TYPE_EXIT &&
(conn->base_.state == EXIT_CONN_STATE_CONNECTING ||
conn->base_.state == EXIT_CONN_STATE_RESOLVING) &&
rh.command == RELAY_COMMAND_DATA) {
/* Allow DATA cells to be delivered to an exit node in state
* EXIT_CONN_STATE_CONNECTING or EXIT_CONN_STATE_RESOLVING.
* This speeds up HTTP, for example. */
optimistic_data = 1;
} else {
return connection_edge_process_relay_cell_not_open(
&rh, cell, circ, conn, layer_hint);
}
}
switch (rh.command) {
case RELAY_COMMAND_DROP:
// log_info(domain,"Got a relay-level padding cell. Dropping.");
return 0;
case RELAY_COMMAND_BEGIN:
case RELAY_COMMAND_BEGIN_DIR:
if (layer_hint &&
circ->purpose != CIRCUIT_PURPOSE_S_REND_JOINED) {
log_fn(LOG_PROTOCOL_WARN, LD_APP,
"Relay begin request unsupported at AP. Dropping.");
return 0;
}
if (circ->purpose == CIRCUIT_PURPOSE_S_REND_JOINED &&
layer_hint != TO_ORIGIN_CIRCUIT(circ)->cpath->prev) {
log_fn(LOG_PROTOCOL_WARN, LD_APP,
"Relay begin request to Hidden Service "
"from intermediary node. Dropping.");
return 0;
}
if (conn) {
log_fn(LOG_PROTOCOL_WARN, domain,
"Begin cell for known stream. Dropping.");
return 0;
}
if (rh.command == RELAY_COMMAND_BEGIN_DIR) {
/* Assign this circuit and its app-ward OR connection a unique ID,
* so that we can measure download times. The local edge and dir
* connection will be assigned the same ID when they are created
* and linked. */
static uint64_t next_id = 0;
circ->dirreq_id = ++next_id;
TO_OR_CIRCUIT(circ)->p_chan->dirreq_id = circ->dirreq_id;
}
return connection_exit_begin_conn(cell, circ);
case RELAY_COMMAND_DATA:
++stats_n_data_cells_received;
if (( layer_hint && --layer_hint->deliver_window < 0) ||
(!layer_hint && --circ->deliver_window < 0)) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"(relay data) circ deliver_window below 0. Killing.");
if (conn) {
/* XXXX Do we actually need to do this? Will killing the circuit
* not send an END and mark the stream for close as appropriate? */
connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL);
connection_mark_for_close(TO_CONN(conn));
}
return -END_CIRC_REASON_TORPROTOCOL;
}
log_debug(domain,"circ deliver_window now %d.", layer_hint ?
layer_hint->deliver_window : circ->deliver_window);
circuit_consider_sending_sendme(circ, layer_hint);
if (!conn) {
log_info(domain,"data cell dropped, unknown stream (streamid %d).",
rh.stream_id);
return 0;
}
if (--conn->deliver_window < 0) { /* is it below 0 after decrement? */
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"(relay data) conn deliver_window below 0. Killing.");
return -END_CIRC_REASON_TORPROTOCOL;
}
stats_n_data_bytes_received += rh.length;
connection_write_to_buf((char*)(cell->payload + RELAY_HEADER_SIZE),
rh.length, TO_CONN(conn));
if (!optimistic_data) {
/* Only send a SENDME if we're not getting optimistic data; otherwise
* a SENDME could arrive before the CONNECTED.
*/
connection_edge_consider_sending_sendme(conn);
}
return 0;
case RELAY_COMMAND_END:
reason = rh.length > 0 ?
get_uint8(cell->payload+RELAY_HEADER_SIZE) : END_STREAM_REASON_MISC;
if (!conn) {
log_info(domain,"end cell (%s) dropped, unknown stream.",
stream_end_reason_to_string(reason));
return 0;
}
/* XXX add to this log_fn the exit node's nickname? */
log_info(domain,TOR_SOCKET_T_FORMAT": end cell (%s) for stream %d. "
"Removing stream.",
conn->base_.s,
stream_end_reason_to_string(reason),
conn->stream_id);
if (conn->base_.type == CONN_TYPE_AP) {
entry_connection_t *entry_conn = EDGE_TO_ENTRY_CONN(conn);
if (entry_conn->socks_request &&
!entry_conn->socks_request->has_finished)
log_warn(LD_BUG,
"open stream hasn't sent socks answer yet? Closing.");
}
/* We just *got* an end; no reason to send one. */
conn->edge_has_sent_end = 1;
if (!conn->end_reason)
conn->end_reason = reason | END_STREAM_REASON_FLAG_REMOTE;
if (!conn->base_.marked_for_close) {
/* only mark it if not already marked. it's possible to
* get the 'end' right around when the client hangs up on us. */
connection_mark_and_flush(TO_CONN(conn));
}
return 0;
case RELAY_COMMAND_EXTEND:
case RELAY_COMMAND_EXTEND2: {
static uint64_t total_n_extend=0, total_nonearly=0;
total_n_extend++;
if (rh.stream_id) {
log_fn(LOG_PROTOCOL_WARN, domain,
"'extend' cell received for non-zero stream. Dropping.");
return 0;
}
if (cell->command != CELL_RELAY_EARLY &&
!networkstatus_get_param(NULL,"AllowNonearlyExtend",0,0,1)) {
#define EARLY_WARNING_INTERVAL 3600
static ratelim_t early_warning_limit =
RATELIM_INIT(EARLY_WARNING_INTERVAL);
char *m;
if (cell->command == CELL_RELAY) {
++total_nonearly;
if ((m = rate_limit_log(&early_warning_limit, approx_time()))) {
double percentage = ((double)total_nonearly)/total_n_extend;
percentage *= 100;
log_fn(LOG_PROTOCOL_WARN, domain, "EXTEND cell received, "
"but not via RELAY_EARLY. Dropping.%s", m);
log_fn(LOG_PROTOCOL_WARN, domain, " (We have dropped %.02f%% of "
"all EXTEND cells for this reason)", percentage);
tor_free(m);
}
} else {
log_fn(LOG_WARN, domain,
"EXTEND cell received, in a cell with type %d! Dropping.",
cell->command);
}
return 0;
}
return circuit_extend(cell, circ);
}
case RELAY_COMMAND_EXTENDED:
case RELAY_COMMAND_EXTENDED2:
if (!layer_hint) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"'extended' unsupported at non-origin. Dropping.");
return 0;
}
log_debug(domain,"Got an extended cell! Yay.");
{
extended_cell_t extended_cell;
if (extended_cell_parse(&extended_cell, rh.command,
(const uint8_t*)cell->payload+RELAY_HEADER_SIZE,
rh.length)<0) {
log_warn(LD_PROTOCOL,
"Can't parse EXTENDED cell; killing circuit.");
return -END_CIRC_REASON_TORPROTOCOL;
}
if ((reason = circuit_finish_handshake(TO_ORIGIN_CIRCUIT(circ),
&extended_cell.created_cell)) < 0) {
log_warn(domain,"circuit_finish_handshake failed.");
return reason;
}
}
if ((reason=circuit_send_next_onion_skin(TO_ORIGIN_CIRCUIT(circ)))<0) {
log_info(domain,"circuit_send_next_onion_skin() failed.");
return reason;
}
return 0;
case RELAY_COMMAND_TRUNCATE:
if (layer_hint) {
log_fn(LOG_PROTOCOL_WARN, LD_APP,
"'truncate' unsupported at origin. Dropping.");
return 0;
}
if (circ->n_hop) {
if (circ->n_chan)
log_warn(LD_BUG, "n_chan and n_hop set on the same circuit!");
extend_info_free(circ->n_hop);
circ->n_hop = NULL;
tor_free(circ->n_chan_create_cell);
circuit_set_state(circ, CIRCUIT_STATE_OPEN);
}
if (circ->n_chan) {
uint8_t trunc_reason = get_uint8(cell->payload + RELAY_HEADER_SIZE);
circuit_clear_cell_queue(circ, circ->n_chan);
channel_send_destroy(circ->n_circ_id, circ->n_chan,
trunc_reason);
circuit_set_n_circid_chan(circ, 0, NULL);
}
log_debug(LD_EXIT, "Processed 'truncate', replying.");
{
char payload[1];
payload[0] = (char)END_CIRC_REASON_REQUESTED;
relay_send_command_from_edge(0, circ, RELAY_COMMAND_TRUNCATED,
payload, sizeof(payload), NULL);
}
return 0;
case RELAY_COMMAND_TRUNCATED:
if (!layer_hint) {
log_fn(LOG_PROTOCOL_WARN, LD_EXIT,
"'truncated' unsupported at non-origin. Dropping.");
return 0;
}
circuit_truncated(TO_ORIGIN_CIRCUIT(circ), layer_hint,
get_uint8(cell->payload + RELAY_HEADER_SIZE));
return 0;
case RELAY_COMMAND_CONNECTED:
if (conn) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"'connected' unsupported while open. Closing circ.");
return -END_CIRC_REASON_TORPROTOCOL;
}
log_info(domain,
"'connected' received, no conn attached anymore. Ignoring.");
return 0;
case RELAY_COMMAND_SENDME:
if (!rh.stream_id) {
if (layer_hint) {
if (layer_hint->package_window + CIRCWINDOW_INCREMENT >
CIRCWINDOW_START_MAX) {
/*XXXX024: Downgrade this back to LOG_PROTOCOL_WARN after a while*/
log_fn(LOG_WARN, LD_PROTOCOL,
"Bug/attack: unexpected sendme cell from exit relay. "
"Closing circ.");
return -END_CIRC_REASON_TORPROTOCOL;
}
layer_hint->package_window += CIRCWINDOW_INCREMENT;
log_debug(LD_APP,"circ-level sendme at origin, packagewindow %d.",
layer_hint->package_window);
circuit_resume_edge_reading(circ, layer_hint);
} else {
if (circ->package_window + CIRCWINDOW_INCREMENT >
CIRCWINDOW_START_MAX) {
/*XXXX024: Downgrade this back to LOG_PROTOCOL_WARN after a while*/
log_fn(LOG_WARN, LD_PROTOCOL,
"Bug/attack: unexpected sendme cell from client. "
"Closing circ (window %d).",
circ->package_window);
return -END_CIRC_REASON_TORPROTOCOL;
}
circ->package_window += CIRCWINDOW_INCREMENT;
log_debug(LD_APP,
"circ-level sendme at non-origin, packagewindow %d.",
circ->package_window);
circuit_resume_edge_reading(circ, layer_hint);
}
return 0;
}
if (!conn) {
log_info(domain,"sendme cell dropped, unknown stream (streamid %d).",
rh.stream_id);
return 0;
}
conn->package_window += STREAMWINDOW_INCREMENT;
log_debug(domain,"stream-level sendme, packagewindow now %d.",
conn->package_window);
if (circuit_queue_streams_are_blocked(circ)) {
/* Still waiting for queue to flush; don't touch conn */
return 0;
}
connection_start_reading(TO_CONN(conn));
/* handle whatever might still be on the inbuf */
if (connection_edge_package_raw_inbuf(conn, 1, NULL) < 0) {
/* (We already sent an end cell if possible) */
connection_mark_for_close(TO_CONN(conn));
return 0;
}
return 0;
case RELAY_COMMAND_RESOLVE:
if (layer_hint) {
log_fn(LOG_PROTOCOL_WARN, LD_APP,
"resolve request unsupported at AP; dropping.");
return 0;
} else if (conn) {
log_fn(LOG_PROTOCOL_WARN, domain,
"resolve request for known stream; dropping.");
return 0;
} else if (circ->purpose != CIRCUIT_PURPOSE_OR) {
log_fn(LOG_PROTOCOL_WARN, domain,
"resolve request on circ with purpose %d; dropping",
circ->purpose);
return 0;
}
connection_exit_begin_resolve(cell, TO_OR_CIRCUIT(circ));
return 0;
case RELAY_COMMAND_RESOLVED:
if (conn) {
log_fn(LOG_PROTOCOL_WARN, domain,
"'resolved' unsupported while open. Closing circ.");
return -END_CIRC_REASON_TORPROTOCOL;
}
log_info(domain,
"'resolved' received, no conn attached anymore. Ignoring.");
return 0;
case RELAY_COMMAND_ESTABLISH_INTRO:
case RELAY_COMMAND_ESTABLISH_RENDEZVOUS:
case RELAY_COMMAND_INTRODUCE1:
case RELAY_COMMAND_INTRODUCE2:
case RELAY_COMMAND_INTRODUCE_ACK:
case RELAY_COMMAND_RENDEZVOUS1:
case RELAY_COMMAND_RENDEZVOUS2:
case RELAY_COMMAND_INTRO_ESTABLISHED:
case RELAY_COMMAND_RENDEZVOUS_ESTABLISHED:
rend_process_relay_cell(circ, layer_hint,
rh.command, rh.length,
cell->payload+RELAY_HEADER_SIZE);
return 0;
}
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Received unknown relay command %d. Perhaps the other side is using "
"a newer version of Tor? Dropping.",
rh.command);
return 0; /* for forward compatibility, don't kill the circuit */
}
/** How many relay_data cells have we built, ever? */
uint64_t stats_n_data_cells_packaged = 0;
/** How many bytes of data have we put in relay_data cells have we built,
* ever? This would be RELAY_PAYLOAD_SIZE*stats_n_data_cells_packaged if
* every relay cell we ever sent were completely full of data. */
uint64_t stats_n_data_bytes_packaged = 0;
/** How many relay_data cells have we received, ever? */
uint64_t stats_n_data_cells_received = 0;
/** How many bytes of data have we received relay_data cells, ever? This would
* be RELAY_PAYLOAD_SIZE*stats_n_data_cells_packaged if every relay cell we
* ever received were completely full of data. */
uint64_t stats_n_data_bytes_received = 0;
/** If <b>conn</b> has an entire relay payload of bytes on its inbuf (or
* <b>package_partial</b> is true), and the appropriate package windows aren't
* empty, grab a cell and send it down the circuit.
*
* If *<b>max_cells</b> is given, package no more than max_cells. Decrement
* *<b>max_cells</b> by the number of cells packaged.
*
* Return -1 (and send a RELAY_COMMAND_END cell if necessary) if conn should
* be marked for close, else return 0.
*/
int
connection_edge_package_raw_inbuf(edge_connection_t *conn, int package_partial,
int *max_cells)
{
size_t bytes_to_process, length;
char payload[CELL_PAYLOAD_SIZE];
circuit_t *circ;
const unsigned domain = conn->base_.type == CONN_TYPE_AP ? LD_APP : LD_EXIT;
int sending_from_optimistic = 0;
entry_connection_t *entry_conn =
conn->base_.type == CONN_TYPE_AP ? EDGE_TO_ENTRY_CONN(conn) : NULL;
const int sending_optimistically =
entry_conn &&
conn->base_.type == CONN_TYPE_AP &&
conn->base_.state != AP_CONN_STATE_OPEN;
crypt_path_t *cpath_layer = conn->cpath_layer;
tor_assert(conn);
if (conn->base_.marked_for_close) {
log_warn(LD_BUG,
"called on conn that's already marked for close at %s:%d.",
conn->base_.marked_for_close_file, conn->base_.marked_for_close);
return 0;
}
if (max_cells && *max_cells <= 0)
return 0;
repeat_connection_edge_package_raw_inbuf:
circ = circuit_get_by_edge_conn(conn);
if (!circ) {
log_info(domain,"conn has no circuit! Closing.");
conn->end_reason = END_STREAM_REASON_CANT_ATTACH;
return -1;
}
if (circuit_consider_stop_edge_reading(circ, cpath_layer))
return 0;
if (conn->package_window <= 0) {
log_info(domain,"called with package_window %d. Skipping.",
conn->package_window);
connection_stop_reading(TO_CONN(conn));
return 0;
}
sending_from_optimistic = entry_conn &&
entry_conn->sending_optimistic_data != NULL;
if (PREDICT_UNLIKELY(sending_from_optimistic)) {
bytes_to_process = generic_buffer_len(entry_conn->sending_optimistic_data);
if (PREDICT_UNLIKELY(!bytes_to_process)) {
log_warn(LD_BUG, "sending_optimistic_data was non-NULL but empty");
bytes_to_process = connection_get_inbuf_len(TO_CONN(conn));
sending_from_optimistic = 0;
}
} else {
bytes_to_process = connection_get_inbuf_len(TO_CONN(conn));
}
if (!bytes_to_process)
return 0;
if (!package_partial && bytes_to_process < RELAY_PAYLOAD_SIZE)
return 0;
if (bytes_to_process > RELAY_PAYLOAD_SIZE) {
length = RELAY_PAYLOAD_SIZE;
} else {
length = bytes_to_process;
}
stats_n_data_bytes_packaged += length;
stats_n_data_cells_packaged += 1;
if (PREDICT_UNLIKELY(sending_from_optimistic)) {
/* XXXX We could be more efficient here by sometimes packing
* previously-sent optimistic data in the same cell with data
* from the inbuf. */
generic_buffer_get(entry_conn->sending_optimistic_data, payload, length);
if (!generic_buffer_len(entry_conn->sending_optimistic_data)) {
generic_buffer_free(entry_conn->sending_optimistic_data);
entry_conn->sending_optimistic_data = NULL;
}
} else {
connection_fetch_from_buf(payload, length, TO_CONN(conn));
}
log_debug(domain,TOR_SOCKET_T_FORMAT": Packaging %d bytes (%d waiting).",
conn->base_.s,
(int)length, (int)connection_get_inbuf_len(TO_CONN(conn)));
if (sending_optimistically && !sending_from_optimistic) {
/* This is new optimistic data; remember it in case we need to detach and
retry */
if (!entry_conn->pending_optimistic_data)
entry_conn->pending_optimistic_data = generic_buffer_new();
generic_buffer_add(entry_conn->pending_optimistic_data, payload, length);
}
if (connection_edge_send_command(conn, RELAY_COMMAND_DATA,
payload, length) < 0 )
/* circuit got marked for close, don't continue, don't need to mark conn */
return 0;
if (!cpath_layer) { /* non-rendezvous exit */
tor_assert(circ->package_window > 0);
circ->package_window--;
} else { /* we're an AP, or an exit on a rendezvous circ */
tor_assert(cpath_layer->package_window > 0);
cpath_layer->package_window--;
}
if (--conn->package_window <= 0) { /* is it 0 after decrement? */
connection_stop_reading(TO_CONN(conn));
log_debug(domain,"conn->package_window reached 0.");
circuit_consider_stop_edge_reading(circ, cpath_layer);
return 0; /* don't process the inbuf any more */
}
log_debug(domain,"conn->package_window is now %d",conn->package_window);
if (max_cells) {
*max_cells -= 1;
if (*max_cells <= 0)
return 0;
}
/* handle more if there's more, or return 0 if there isn't */
goto repeat_connection_edge_package_raw_inbuf;
}
/** Called when we've just received a relay data cell, when
* we've just finished flushing all bytes to stream <b>conn</b>,
* or when we've flushed *some* bytes to the stream <b>conn</b>.
*
* If conn->outbuf is not too full, and our deliver window is
* low, send back a suitable number of stream-level sendme cells.
*/
void
connection_edge_consider_sending_sendme(edge_connection_t *conn)
{
circuit_t *circ;
if (connection_outbuf_too_full(TO_CONN(conn)))
return;
circ = circuit_get_by_edge_conn(conn);
if (!circ) {
/* this can legitimately happen if the destroy has already
* arrived and torn down the circuit */
log_info(LD_APP,"No circuit associated with conn. Skipping.");
return;
}
while (conn->deliver_window <= STREAMWINDOW_START - STREAMWINDOW_INCREMENT) {
log_debug(conn->base_.type == CONN_TYPE_AP ?LD_APP:LD_EXIT,
"Outbuf %d, Queuing stream sendme.",
(int)conn->base_.outbuf_flushlen);
conn->deliver_window += STREAMWINDOW_INCREMENT;
if (connection_edge_send_command(conn, RELAY_COMMAND_SENDME,
NULL, 0) < 0) {
log_warn(LD_APP,"connection_edge_send_command failed. Skipping.");
return; /* the circuit's closed, don't continue */
}
}
}
/** The circuit <b>circ</b> has received a circuit-level sendme
* (on hop <b>layer_hint</b>, if we're the OP). Go through all the
* attached streams and let them resume reading and packaging, if
* their stream windows allow it.
*/
static void
circuit_resume_edge_reading(circuit_t *circ, crypt_path_t *layer_hint)
{
if (circuit_queue_streams_are_blocked(circ)) {
log_debug(layer_hint?LD_APP:LD_EXIT,"Too big queue, no resuming");
return;
}
log_debug(layer_hint?LD_APP:LD_EXIT,"resuming");
if (CIRCUIT_IS_ORIGIN(circ))
circuit_resume_edge_reading_helper(TO_ORIGIN_CIRCUIT(circ)->p_streams,
circ, layer_hint);
else
circuit_resume_edge_reading_helper(TO_OR_CIRCUIT(circ)->n_streams,
circ, layer_hint);
}
void
stream_choice_seed_weak_rng(void)
{
crypto_seed_weak_rng(&stream_choice_rng);
}
/** A helper function for circuit_resume_edge_reading() above.
* The arguments are the same, except that <b>conn</b> is the head
* of a linked list of edge streams that should each be considered.
*/
static int
circuit_resume_edge_reading_helper(edge_connection_t *first_conn,
circuit_t *circ,
crypt_path_t *layer_hint)
{
edge_connection_t *conn;
int n_packaging_streams, n_streams_left;
int packaged_this_round;
int cells_on_queue;
int cells_per_conn;
edge_connection_t *chosen_stream = NULL;
int max_to_package;
if (first_conn == NULL) {
/* Don't bother to try to do the rest of this if there are no connections
* to resume. */
return 0;
}
/* How many cells do we have space for? It will be the minimum of
* the number needed to exhaust the package window, and the minimum
* needed to fill the cell queue. */
max_to_package = circ->package_window;
if (CIRCUIT_IS_ORIGIN(circ)) {
cells_on_queue = circ->n_chan_cells.n;
} else {
or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
cells_on_queue = or_circ->p_chan_cells.n;
}
if (CELL_QUEUE_HIGHWATER_SIZE - cells_on_queue < max_to_package)
max_to_package = CELL_QUEUE_HIGHWATER_SIZE - cells_on_queue;
/* Once we used to start listening on the streams in the order they
* appeared in the linked list. That leads to starvation on the
* streams that appeared later on the list, since the first streams
* would always get to read first. Instead, we just pick a random
* stream on the list, and enable reading for streams starting at that
* point (and wrapping around as if the list were circular). It would
* probably be better to actually remember which streams we've
* serviced in the past, but this is simple and effective. */
/* Select a stream uniformly at random from the linked list. We
* don't need cryptographic randomness here. */
{
int num_streams = 0;
for (conn = first_conn; conn; conn = conn->next_stream) {
num_streams++;
if (tor_weak_random_one_in_n(&stream_choice_rng, num_streams)) {
chosen_stream = conn;
}
/* Invariant: chosen_stream has been chosen uniformly at random from
* among the first num_streams streams on first_conn.
*
* (Note that we iterate over every stream on the circuit, so that after
* we've considered the first stream, we've chosen it with P=1; and
* after we consider the second stream, we've switched to it with P=1/2
* and stayed with the first stream with P=1/2; and after we've
* considered the third stream, we've switched to it with P=1/3 and
* remained with one of the first two streams with P=(2/3), giving each
* one P=(1/2)(2/3) )=(1/3).) */
}
}
/* Count how many non-marked streams there are that have anything on
* their inbuf, and enable reading on all of the connections. */
n_packaging_streams = 0;
/* Activate reading starting from the chosen stream */
for (conn=chosen_stream; conn; conn = conn->next_stream) {
/* Start reading for the streams starting from here */
if (conn->base_.marked_for_close || conn->package_window <= 0)
continue;
if (!layer_hint || conn->cpath_layer == layer_hint) {
connection_start_reading(TO_CONN(conn));
if (connection_get_inbuf_len(TO_CONN(conn)) > 0)
++n_packaging_streams;
}
}
/* Go back and do the ones we skipped, circular-style */
for (conn = first_conn; conn != chosen_stream; conn = conn->next_stream) {
if (conn->base_.marked_for_close || conn->package_window <= 0)
continue;
if (!layer_hint || conn->cpath_layer == layer_hint) {
connection_start_reading(TO_CONN(conn));
if (connection_get_inbuf_len(TO_CONN(conn)) > 0)
++n_packaging_streams;
}
}
if (n_packaging_streams == 0) /* avoid divide-by-zero */
return 0;
again:
cells_per_conn = CEIL_DIV(max_to_package, n_packaging_streams);
packaged_this_round = 0;
n_streams_left = 0;
/* Iterate over all connections. Package up to cells_per_conn cells on
* each. Update packaged_this_round with the total number of cells
* packaged, and n_streams_left with the number that still have data to
* package.
*/
for (conn=first_conn; conn; conn=conn->next_stream) {
if (conn->base_.marked_for_close || conn->package_window <= 0)
continue;
if (!layer_hint || conn->cpath_layer == layer_hint) {
int n = cells_per_conn, r;
/* handle whatever might still be on the inbuf */
r = connection_edge_package_raw_inbuf(conn, 1, &n);
/* Note how many we packaged */
packaged_this_round += (cells_per_conn-n);
if (r<0) {
/* Problem while packaging. (We already sent an end cell if
* possible) */
connection_mark_for_close(TO_CONN(conn));
continue;
}
/* If there's still data to read, we'll be coming back to this stream. */
if (connection_get_inbuf_len(TO_CONN(conn)))
++n_streams_left;
/* If the circuit won't accept any more data, return without looking
* at any more of the streams. Any connections that should be stopped
* have already been stopped by connection_edge_package_raw_inbuf. */
if (circuit_consider_stop_edge_reading(circ, layer_hint))
return -1;
/* XXXX should we also stop immediately if we fill up the cell queue?
* Probably. */
}
}
/* If we made progress, and we are willing to package more, and there are
* any streams left that want to package stuff... try again!
*/
if (packaged_this_round && packaged_this_round < max_to_package &&
n_streams_left) {
max_to_package -= packaged_this_round;
n_packaging_streams = n_streams_left;
goto again;
}
return 0;
}
/** Check if the package window for <b>circ</b> is empty (at
* hop <b>layer_hint</b> if it's defined).
*
* If yes, tell edge streams to stop reading and return 1.
* Else return 0.
*/
static int
circuit_consider_stop_edge_reading(circuit_t *circ, crypt_path_t *layer_hint)
{
edge_connection_t *conn = NULL;
unsigned domain = layer_hint ? LD_APP : LD_EXIT;
if (!layer_hint) {
or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
log_debug(domain,"considering circ->package_window %d",
circ->package_window);
if (circ->package_window <= 0) {
log_debug(domain,"yes, not-at-origin. stopped.");
for (conn = or_circ->n_streams; conn; conn=conn->next_stream)
connection_stop_reading(TO_CONN(conn));
return 1;
}
return 0;
}
/* else, layer hint is defined, use it */
log_debug(domain,"considering layer_hint->package_window %d",
layer_hint->package_window);
if (layer_hint->package_window <= 0) {
log_debug(domain,"yes, at-origin. stopped.");
for (conn = TO_ORIGIN_CIRCUIT(circ)->p_streams; conn;
conn=conn->next_stream) {
if (conn->cpath_layer == layer_hint)
connection_stop_reading(TO_CONN(conn));
}
return 1;
}
return 0;
}
/** Check if the deliver_window for circuit <b>circ</b> (at hop
* <b>layer_hint</b> if it's defined) is low enough that we should
* send a circuit-level sendme back down the circuit. If so, send
* enough sendmes that the window would be overfull if we sent any
* more.
*/
static void
circuit_consider_sending_sendme(circuit_t *circ, crypt_path_t *layer_hint)
{
// log_fn(LOG_INFO,"Considering: layer_hint is %s",
// layer_hint ? "defined" : "null");
while ((layer_hint ? layer_hint->deliver_window : circ->deliver_window) <=
CIRCWINDOW_START - CIRCWINDOW_INCREMENT) {
log_debug(LD_CIRC,"Queuing circuit sendme.");
if (layer_hint)
layer_hint->deliver_window += CIRCWINDOW_INCREMENT;
else
circ->deliver_window += CIRCWINDOW_INCREMENT;
if (relay_send_command_from_edge(0, circ, RELAY_COMMAND_SENDME,
NULL, 0, layer_hint) < 0) {
log_warn(LD_CIRC,
"relay_send_command_from_edge failed. Circuit's closed.");
return; /* the circuit's closed, don't continue */
}
}
}
#ifdef ACTIVE_CIRCUITS_PARANOIA
#define assert_cmux_ok_paranoid(chan) \
assert_circuit_mux_okay(chan)
#else
#define assert_cmux_ok_paranoid(chan)
#endif
/** The total number of cells we have allocated from the memory pool. */
static int total_cells_allocated = 0;
/** A memory pool to allocate packed_cell_t objects. */
static mp_pool_t *cell_pool = NULL;
/** Memory pool to allocate insertion_time_elem_t objects used for cell
* statistics. */
static mp_pool_t *it_pool = NULL;
/** Allocate structures to hold cells. */
void
init_cell_pool(void)
{
tor_assert(!cell_pool);
cell_pool = mp_pool_new(sizeof(packed_cell_t), 128*1024);
}
/** Free all storage used to hold cells (and insertion times if we measure
* cell statistics). */
void
free_cell_pool(void)
{
/* Maybe we haven't called init_cell_pool yet; need to check for it. */
if (cell_pool) {
mp_pool_destroy(cell_pool);
cell_pool = NULL;
}
if (it_pool) {
mp_pool_destroy(it_pool);
it_pool = NULL;
}
}
/** Free excess storage in cell pool. */
void
clean_cell_pool(void)
{
tor_assert(cell_pool);
mp_pool_clean(cell_pool, 0, 1);
}
/** Release storage held by <b>cell</b>. */
static INLINE void
packed_cell_free_unchecked(packed_cell_t *cell)
{
--total_cells_allocated;
mp_pool_release(cell);
}
/** Allocate and return a new packed_cell_t. */
static INLINE packed_cell_t *
packed_cell_new(void)
{
++total_cells_allocated;
return mp_pool_get(cell_pool);
}
/** Return a packed cell used outside by channel_t lower layer */
void
packed_cell_free(packed_cell_t *cell)
{
packed_cell_free_unchecked(cell);
}
/** Log current statistics for cell pool allocation at log level
* <b>severity</b>. */
void
dump_cell_pool_usage(int severity)
{
circuit_t *c;
int n_circs = 0;
int n_cells = 0;
for (c = circuit_get_global_list_(); c; c = c->next) {
n_cells += c->n_chan_cells.n;
if (!CIRCUIT_IS_ORIGIN(c))
n_cells += TO_OR_CIRCUIT(c)->p_chan_cells.n;
++n_circs;
}
tor_log(severity, LD_MM,
"%d cells allocated on %d circuits. %d cells leaked.",
n_cells, n_circs, total_cells_allocated - n_cells);
mp_pool_log_status(cell_pool, severity);
}
/** Allocate a new copy of packed <b>cell</b>. */
static INLINE packed_cell_t *
packed_cell_copy(const cell_t *cell, int wide_circ_ids)
{
packed_cell_t *c = packed_cell_new();
cell_pack(c, cell, wide_circ_ids);
c->next = NULL;
return c;
}
/** Append <b>cell</b> to the end of <b>queue</b>. */
void
cell_queue_append(cell_queue_t *queue, packed_cell_t *cell)
{
if (queue->tail) {
tor_assert(!queue->tail->next);
queue->tail->next = cell;
} else {
queue->head = cell;
}
queue->tail = cell;
cell->next = NULL;
++queue->n;
}
/** Append a newly allocated copy of <b>cell</b> to the end of <b>queue</b> */
void
cell_queue_append_packed_copy(cell_queue_t *queue, const cell_t *cell,
int wide_circ_ids, int use_stats)
{
packed_cell_t *copy = packed_cell_copy(cell, wide_circ_ids);
/* Remember the time when this cell was put in the queue. */
if (get_options()->CellStatistics && use_stats) {
struct timeval now;
uint32_t added;
insertion_time_queue_t *it_queue = queue->insertion_times;
if (!it_pool)
it_pool = mp_pool_new(sizeof(insertion_time_elem_t), 1024);
tor_gettimeofday_cached(&now);
#define SECONDS_IN_A_DAY 86400L
added = (uint32_t)(((now.tv_sec % SECONDS_IN_A_DAY) * 100L)
+ ((uint32_t)now.tv_usec / (uint32_t)10000L));
if (!it_queue) {
it_queue = tor_malloc_zero(sizeof(insertion_time_queue_t));
queue->insertion_times = it_queue;
}
if (it_queue->last && it_queue->last->insertion_time == added) {
it_queue->last->counter++;
} else {
insertion_time_elem_t *elem = mp_pool_get(it_pool);
elem->next = NULL;
elem->insertion_time = added;
elem->counter = 1;
if (it_queue->last) {
it_queue->last->next = elem;
it_queue->last = elem;
} else {
it_queue->first = it_queue->last = elem;
}
}
}
cell_queue_append(queue, copy);
}
/** Remove and free every cell in <b>queue</b>. */
void
cell_queue_clear(cell_queue_t *queue)
{
packed_cell_t *cell, *next;
cell = queue->head;
while (cell) {
next = cell->next;
packed_cell_free_unchecked(cell);
cell = next;
}
queue->head = queue->tail = NULL;
queue->n = 0;
if (queue->insertion_times) {
while (queue->insertion_times->first) {
insertion_time_elem_t *elem = queue->insertion_times->first;
queue->insertion_times->first = elem->next;
mp_pool_release(elem);
}
tor_free(queue->insertion_times);
}
}
/** Extract and return the cell at the head of <b>queue</b>; return NULL if
* <b>queue</b> is empty. */
static INLINE packed_cell_t *
cell_queue_pop(cell_queue_t *queue)
{
packed_cell_t *cell = queue->head;
if (!cell)
return NULL;
queue->head = cell->next;
if (cell == queue->tail) {
tor_assert(!queue->head);
queue->tail = NULL;
}
--queue->n;
return cell;
}
/**
* Update the number of cells available on the circuit's n_chan or p_chan's
* circuit mux.
*/
void
update_circuit_on_cmux_(circuit_t *circ, cell_direction_t direction,
const char *file, int lineno)
{
channel_t *chan = NULL;
or_circuit_t *or_circ = NULL;
circuitmux_t *cmux = NULL;
tor_assert(circ);
/* Okay, get the channel */
if (direction == CELL_DIRECTION_OUT) {
chan = circ->n_chan;
} else {
or_circ = TO_OR_CIRCUIT(circ);
chan = or_circ->p_chan;
}
tor_assert(chan);
tor_assert(chan->cmux);
/* Now get the cmux */
cmux = chan->cmux;
/* Cmux sanity check */
if (! circuitmux_is_circuit_attached(cmux, circ)) {
log_warn(LD_BUG, "called on non-attachd circuit from %s:%d",
file, lineno);
return;
}
tor_assert(circuitmux_attached_circuit_direction(cmux, circ) == direction);
assert_cmux_ok_paranoid(chan);
/* Update the number of cells we have for the circuit mux */
if (direction == CELL_DIRECTION_OUT) {
circuitmux_set_num_cells(cmux, circ, circ->n_chan_cells.n);
} else {
circuitmux_set_num_cells(cmux, circ, or_circ->p_chan_cells.n);
}
assert_cmux_ok_paranoid(chan);
}
/** Remove all circuits from the cmux on <b>chan</b>. */
void
channel_unlink_all_circuits(channel_t *chan)
{
tor_assert(chan);
tor_assert(chan->cmux);
circuitmux_detach_all_circuits(chan->cmux);
chan->num_n_circuits = 0;
chan->num_p_circuits = 0;
}
/** Block (if <b>block</b> is true) or unblock (if <b>block</b> is false)
* every edge connection that is using <b>circ</b> to write to <b>chan</b>,
* and start or stop reading as appropriate.
*
* If <b>stream_id</b> is nonzero, block only the edge connection whose
* stream_id matches it.
*
* Returns the number of streams whose status we changed.
*/
static int
set_streams_blocked_on_circ(circuit_t *circ, channel_t *chan,
int block, streamid_t stream_id)
{
edge_connection_t *edge = NULL;
int n = 0;
if (circ->n_chan == chan) {
circ->streams_blocked_on_n_chan = block;
if (CIRCUIT_IS_ORIGIN(circ))
edge = TO_ORIGIN_CIRCUIT(circ)->p_streams;
} else {
circ->streams_blocked_on_p_chan = block;
tor_assert(!CIRCUIT_IS_ORIGIN(circ));
edge = TO_OR_CIRCUIT(circ)->n_streams;
}
for (; edge; edge = edge->next_stream) {
connection_t *conn = TO_CONN(edge);
if (stream_id && edge->stream_id != stream_id)
continue;
if (edge->edge_blocked_on_circ != block) {
++n;
edge->edge_blocked_on_circ = block;
}
if (!conn->read_event && !HAS_BUFFEREVENT(conn)) {
/* This connection is a placeholder for something; probably a DNS
* request. It can't actually stop or start reading.*/
continue;
}
if (block) {
if (connection_is_reading(conn))
connection_stop_reading(conn);
} else {
/* Is this right? */
if (!connection_is_reading(conn))
connection_start_reading(conn);
}
}
return n;
}
/** Pull as many cells as possible (but no more than <b>max</b>) from the
* queue of the first active circuit on <b>chan</b>, and write them to
* <b>chan</b>-&gt;outbuf. Return the number of cells written. Advance
* the active circuit pointer to the next active circuit in the ring. */
int
channel_flush_from_first_active_circuit(channel_t *chan, int max)
{
circuitmux_t *cmux = NULL;
int n_flushed = 0;
cell_queue_t *queue, *destroy_queue=NULL;
circuit_t *circ;
or_circuit_t *or_circ;
int streams_blocked;
packed_cell_t *cell;
/* Get the cmux */
tor_assert(chan);
tor_assert(chan->cmux);
cmux = chan->cmux;
/* Main loop: pick a circuit, send a cell, update the cmux */
while (n_flushed < max) {
circ = circuitmux_get_first_active_circuit(cmux, &destroy_queue);
if (destroy_queue) {
/* this code is duplicated from some of the logic below. Ugly! XXXX */
tor_assert(destroy_queue->n > 0);
cell = cell_queue_pop(destroy_queue);
channel_write_packed_cell(chan, cell);
/* Update the cmux destroy counter */
circuitmux_notify_xmit_destroy(cmux);
cell = NULL;
++n_flushed;
continue;
}
/* If it returns NULL, no cells left to send */
if (!circ) break;
assert_cmux_ok_paranoid(chan);
if (circ->n_chan == chan) {
queue = &circ->n_chan_cells;
streams_blocked = circ->streams_blocked_on_n_chan;
} else {
or_circ = TO_OR_CIRCUIT(circ);
tor_assert(or_circ->p_chan == chan);
queue = &TO_OR_CIRCUIT(circ)->p_chan_cells;
streams_blocked = circ->streams_blocked_on_p_chan;
}
/* Circuitmux told us this was active, so it should have cells */
tor_assert(queue->n > 0);
/*
* Get just one cell here; once we've sent it, that can change the circuit
* selection, so we have to loop around for another even if this circuit
* has more than one.
*/
cell = cell_queue_pop(queue);
/* Calculate the exact time that this cell has spent in the queue. */
if (get_options()->CellStatistics && !CIRCUIT_IS_ORIGIN(circ)) {
struct timeval tvnow;
uint32_t flushed;
uint32_t cell_waiting_time;
insertion_time_queue_t *it_queue = queue->insertion_times;
tor_gettimeofday_cached(&tvnow);
flushed = (uint32_t)((tvnow.tv_sec % SECONDS_IN_A_DAY) * 100L +
(uint32_t)tvnow.tv_usec / (uint32_t)10000L);
if (!it_queue || !it_queue->first) {
log_info(LD_GENERAL, "Cannot determine insertion time of cell. "
"Looks like the CellStatistics option was "
"recently enabled.");
} else {
insertion_time_elem_t *elem = it_queue->first;
or_circ = TO_OR_CIRCUIT(circ);
cell_waiting_time =
(uint32_t)((flushed * 10L + SECONDS_IN_A_DAY * 1000L -
elem->insertion_time * 10L) %
(SECONDS_IN_A_DAY * 1000L));
#undef SECONDS_IN_A_DAY
elem->counter--;
if (elem->counter < 1) {
it_queue->first = elem->next;
if (elem == it_queue->last)
it_queue->last = NULL;
mp_pool_release(elem);
}
or_circ->total_cell_waiting_time += cell_waiting_time;
or_circ->processed_cells++;
}
}
/* If we just flushed our queue and this circuit is used for a
* tunneled directory request, possibly advance its state. */
if (queue->n == 0 && chan->dirreq_id)
geoip_change_dirreq_state(chan->dirreq_id,
DIRREQ_TUNNELED,
DIRREQ_CIRC_QUEUE_FLUSHED);
/* Now send the cell */
channel_write_packed_cell(chan, cell);
cell = NULL;
/*
* Don't packed_cell_free_unchecked(cell) here because the channel will
* do so when it gets out of the channel queue (probably already did, in
* which case that was an immediate double-free bug).
*/
/* Update the counter */
++n_flushed;
/*
* Now update the cmux; tell it we've just sent a cell, and how many
* we have left.
*/
circuitmux_notify_xmit_cells(cmux, circ, 1);
circuitmux_set_num_cells(cmux, circ, queue->n);
if (queue->n == 0)
log_debug(LD_GENERAL, "Made a circuit inactive.");
/* Is the cell queue low enough to unblock all the streams that are waiting
* to write to this circuit? */
if (streams_blocked && queue->n <= CELL_QUEUE_LOWWATER_SIZE)
set_streams_blocked_on_circ(circ, chan, 0, 0); /* unblock streams */
/* If n_flushed < max still, loop around and pick another circuit */
}
/* Okay, we're done sending now */
assert_cmux_ok_paranoid(chan);
return n_flushed;
}
/** Add <b>cell</b> to the queue of <b>circ</b> writing to <b>chan</b>
* transmitting in <b>direction</b>. */
void
append_cell_to_circuit_queue(circuit_t *circ, channel_t *chan,
cell_t *cell, cell_direction_t direction,
streamid_t fromstream)
{
cell_queue_t *queue;
int streams_blocked;
if (circ->marked_for_close)
return;
if (direction == CELL_DIRECTION_OUT) {
queue = &circ->n_chan_cells;
streams_blocked = circ->streams_blocked_on_n_chan;
} else {
or_circuit_t *orcirc = TO_OR_CIRCUIT(circ);
queue = &orcirc->p_chan_cells;
streams_blocked = circ->streams_blocked_on_p_chan;
}
cell_queue_append_packed_copy(queue, cell, chan->wide_circ_ids, 1);
/* If we have too many cells on the circuit, we should stop reading from
* the edge streams for a while. */
if (!streams_blocked && queue->n >= CELL_QUEUE_HIGHWATER_SIZE)
set_streams_blocked_on_circ(circ, chan, 1, 0); /* block streams */
if (streams_blocked && fromstream) {
/* This edge connection is apparently not blocked; block it. */
set_streams_blocked_on_circ(circ, chan, 1, fromstream);
}
update_circuit_on_cmux(circ, direction);
if (queue->n == 1) {
/* This was the first cell added to the queue. We just made this
* circuit active. */
log_debug(LD_GENERAL, "Made a circuit active.");
}
if (!channel_has_queued_writes(chan)) {
/* There is no data at all waiting to be sent on the outbuf. Add a
* cell, so that we can notice when it gets flushed, flushed_some can
* get called, and we can start putting more data onto the buffer then.
*/
log_debug(LD_GENERAL, "Primed a buffer.");
channel_flush_from_first_active_circuit(chan, 1);
}
}
/** Append an encoded value of <b>addr</b> to <b>payload_out</b>, which must
* have at least 18 bytes of free space. The encoding is, as specified in
* tor-spec.txt:
* RESOLVED_TYPE_IPV4 or RESOLVED_TYPE_IPV6 [1 byte]
* LENGTH [1 byte]
* ADDRESS [length bytes]
* Return the number of bytes added, or -1 on error */
int
append_address_to_payload(uint8_t *payload_out, const tor_addr_t *addr)
{
uint32_t a;
switch (tor_addr_family(addr)) {
case AF_INET:
payload_out[0] = RESOLVED_TYPE_IPV4;
payload_out[1] = 4;
a = tor_addr_to_ipv4n(addr);
memcpy(payload_out+2, &a, 4);
return 6;
case AF_INET6:
payload_out[0] = RESOLVED_TYPE_IPV6;
payload_out[1] = 16;
memcpy(payload_out+2, tor_addr_to_in6_addr8(addr), 16);
return 18;
case AF_UNSPEC:
default:
return -1;
}
}
/** Given <b>payload_len</b> bytes at <b>payload</b>, starting with an address
* encoded as by append_address_to_payload(), try to decode the address into
* *<b>addr_out</b>. Return the next byte in the payload after the address on
* success, or NULL on failure. */
const uint8_t *
decode_address_from_payload(tor_addr_t *addr_out, const uint8_t *payload,
int payload_len)
{
if (payload_len < 2)
return NULL;
if (payload_len < 2+payload[1])
return NULL;
switch (payload[0]) {
case RESOLVED_TYPE_IPV4:
if (payload[1] != 4)
return NULL;
tor_addr_from_ipv4n(addr_out, get_uint32(payload+2));
break;
case RESOLVED_TYPE_IPV6:
if (payload[1] != 16)
return NULL;
tor_addr_from_ipv6_bytes(addr_out, (char*)(payload+2));
break;
default:
tor_addr_make_unspec(addr_out);
break;
}
return payload + 2 + payload[1];
}
/** Remove all the cells queued on <b>circ</b> for <b>chan</b>. */
void
circuit_clear_cell_queue(circuit_t *circ, channel_t *chan)
{
cell_queue_t *queue;
cell_direction_t direction;
if (circ->n_chan == chan) {
queue = &circ->n_chan_cells;
direction = CELL_DIRECTION_OUT;
} else {
or_circuit_t *orcirc = TO_OR_CIRCUIT(circ);
tor_assert(orcirc->p_chan == chan);
queue = &orcirc->p_chan_cells;
direction = CELL_DIRECTION_IN;
}
/* Clear the queue */
cell_queue_clear(queue);
/* Update the cell counter in the cmux */
if (chan->cmux && circuitmux_is_circuit_attached(chan->cmux, circ))
update_circuit_on_cmux(circ, direction);
}
/** Fail with an assert if the circuit mux on chan is corrupt
*/
void
assert_circuit_mux_okay(channel_t *chan)
{
tor_assert(chan);
tor_assert(chan->cmux);
circuitmux_assert_okay(chan->cmux);
}
/** Return 1 if we shouldn't restart reading on this circuit, even if
* we get a SENDME. Else return 0.
*/
static int
circuit_queue_streams_are_blocked(circuit_t *circ)
{
if (CIRCUIT_IS_ORIGIN(circ)) {
return circ->streams_blocked_on_n_chan;
} else {
return circ->streams_blocked_on_p_chan;
}
}
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