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43d53e6d86
tor/src/or/relay.c
Nick Mathewson 43d53e6d86 Implementation of a fix for bug 7912 
I added the code to pass a destroy cell to a queueing function rather
than writing it immediately, and the code to remember that we
shouldn't reuse the circuit id until the destroy is actually sent, and
the code to release the circuit id once the destroy has been sent...
and then I finished by hooking destroy_cell_queue into the rest of
Tor.
2013-06-13 10:14:00 -04:00

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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);
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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