/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. */
/* See LICENSE for licensing information */
/* $Id$ */
const char relay_c_id[] =
"$Id$";
/**
* \file relay.c
* \brief Handle relay cell encryption/decryption, plus packaging and
* receiving from circuits.
**/
#include "or.h"
static int relay_crypt(circuit_t *circ, cell_t *cell, int cell_direction,
crypt_path_t **layer_hint, char *recognized);
static connection_t *relay_lookup_conn(circuit_t *circ, cell_t *cell,
int cell_direction);
static int
connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
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(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);
/** 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;
/** Update digest from the payload of cell. Assign integrity part to
* cell.
*/
static void
relay_set_digest(crypto_digest_env_t *digest, cell_t *cell)
{
char integrity[4];
relay_header_t rh;
crypto_digest_add_bytes(digest, 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_env_t *digest, cell_t *cell)
{
char received_integrity[4], calculated_integrity[4];
relay_header_t rh;
crypto_digest_env_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, cell->payload, CELL_PAYLOAD_SIZE);
crypto_digest_get_digest(digest, calculated_integrity, 4);
if (memcmp(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_free_digest_env(backup_digest);
return 0;
}
crypto_free_digest_env(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_env_t *cipher, char *in,
int encrypt_mode)
{
char out[CELL_PAYLOAD_SIZE]; /* 'in' must be this size too */
int r;
if (encrypt_mode)
r = crypto_cipher_encrypt(cipher, out, in, CELL_PAYLOAD_SIZE);
else
r = crypto_cipher_decrypt(cipher, out, in, CELL_PAYLOAD_SIZE);
if (r) {
log_warn(LD_BUG,"Error during relay encryption");
return -1;
}
memcpy(in,out,CELL_PAYLOAD_SIZE);
return 0;
}
/** Receive a relay cell:
* - Crypt it (encrypt APward, decrypt at AP, decrypt exitward).
* - Check if recognized (if exitward).
* - If recognized and the digest checks out, then find if there's
* a conn that the cell is intended for, and deliver it to
* connection_edge.
* - Else connection_or_write_cell_to_buf to the conn on the other
* side of the circuit.
*
* Return -reason on failure.
*/
int
circuit_receive_relay_cell(cell_t *cell, circuit_t *circ, int cell_direction)
{
connection_t *conn=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 -1;
}
if (recognized) {
conn = relay_lookup_conn(circ, cell, cell_direction);
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 */
conn = circ->n_conn;
} else {
cell->circ_id = circ->p_circ_id; /* switch it */
conn = circ->p_conn;
}
if (!conn) {
if (circ->rend_splice && cell_direction == CELL_DIRECTION_OUT) {
tor_assert(circ->purpose == CIRCUIT_PURPOSE_REND_ESTABLISHED);
tor_assert(circ->rend_splice->purpose ==
CIRCUIT_PURPOSE_REND_ESTABLISHED);
cell->circ_id = circ->rend_splice->p_circ_id;
if ((reason = circuit_receive_relay_cell(cell, circ->rend_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;
connection_or_write_cell_to_buf(cell, conn);
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.
*/
/* wrap this into receive_relay_cell one day */
static int
relay_crypt(circuit_t *circ, cell_t *cell, int cell_direction,
crypt_path_t **layer_hint, char *recognized)
{
crypt_path_t *thishop;
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. */
tor_assert(circ->cpath);
thishop = circ->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 != circ->cpath && thishop->state == CPATH_STATE_OPEN);
log_warn(LD_OR,"in-cell at OP not recognized. Closing.");
return -1;
} else { /* we're in the middle. Just one crypt. */
if (relay_crypt_one_payload(circ->p_crypto, cell->payload, 1) < 0)
return -1;
// log_fn(LOG_DEBUG,"Skipping recognized check, because we're not "
// "the OP.");
}
} else /* cell_direction == CELL_DIRECTION_OUT */ {
/* we're in the middle. Just one crypt. */
if (relay_crypt_one_payload(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(circ->n_digest, cell)) {
*recognized = 1;
return 0;
}
}
}
return 0;
}
/** Package a relay cell:
* - Encrypt it to the right layer
* - connection_or_write_cell_to_buf to the right conn
*/
static int
circuit_package_relay_cell(cell_t *cell, circuit_t *circ,
int cell_direction,
crypt_path_t *layer_hint)
{
connection_t *conn; /* where to send the cell */
crypt_path_t *thishop; /* counter for repeated crypts */
if (cell_direction == CELL_DIRECTION_OUT) {
conn = circ->n_conn;
if (!conn) {
log_warn(LD_BUG,"outgoing relay cell has n_conn==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 != circ->cpath->prev);
} else { /* incoming cell */
conn = circ->p_conn;
if (!conn) {
/* XXXX RD This is a bug, right? */
log_warn(LD_BUG,"incoming relay cell has p_conn==NULL. Dropping.");
assert_circuit_ok(circ);
return 0; /* just drop it */
}
relay_set_digest(circ->p_digest, cell);
if (relay_crypt_one_payload(circ->p_crypto, cell->payload, 1) < 0)
return -1;
}
++stats_n_relay_cells_relayed;
connection_or_write_cell_to_buf(cell, conn);
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 connection_t *
relay_lookup_conn(circuit_t *circ, cell_t *cell, int cell_direction)
{
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.
*/
for (tmpconn = circ->n_streams; tmpconn; tmpconn=tmpconn->next_stream) {
if (rh.stream_id == tmpconn->stream_id && !tmpconn->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 = circ->p_streams; tmpconn; tmpconn=tmpconn->next_stream) {
if (rh.stream_id == tmpconn->stream_id && !tmpconn->marked_for_close) {
log_debug(LD_APP,"found conn for stream %d.", rh.stream_id);
return tmpconn;
}
}
for (tmpconn = circ->resolving_streams; tmpconn;
tmpconn=tmpconn->next_stream) {
if (rh.stream_id == tmpconn->stream_id && !tmpconn->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(char *dest, const relay_header_t *src)
{
*(uint8_t*)(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 char *src)
{
dest->command = *(uint8_t*)(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));
}
/** 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(connection_t *fromconn, circuit_t *circ,
int relay_command, const char *payload,
size_t payload_len, crypt_path_t *cpath_layer)
{
cell_t cell;
relay_header_t rh;
int cell_direction;
if (fromconn && fromconn->marked_for_close) {
log_warn(LD_BUG,
"Bug: called on conn that's already marked for close at %s:%d.",
fromconn->marked_for_close_file, fromconn->marked_for_close);
return 0;
}
if (!circ) {
tor_assert(fromconn);
if (fromconn->type == CONN_TYPE_AP) {
log_info(LD_APP,"no circ. Closing conn.");
connection_mark_unattached_ap(fromconn, END_STREAM_REASON_INTERNAL);
} else {
log_info(LD_EXIT,"no circ. Closing conn.");
fromconn->has_sent_end = 1; /* no circ to send to */
connection_mark_for_close(fromconn);
}
return -1;
}
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 {
cell.circ_id = circ->p_circ_id;
cell_direction = CELL_DIRECTION_IN;
}
memset(&rh, 0, sizeof(rh));
rh.command = relay_command;
if (fromconn)
rh.stream_id = fromconn->stream_id; /* else it's 0 */
rh.length = payload_len;
relay_header_pack(cell.payload, &rh);
if (payload_len) {
tor_assert(payload_len <= RELAY_PAYLOAD_SIZE);
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 (circuit_package_relay_cell(&cell, circ, cell_direction, cpath_layer)
< 0) {
log_warn(LD_BUG,"circuit_package_relay_cell failed. Closing.");
circuit_mark_for_close(circ, END_CIRC_REASON_INTERNAL);
return -1;
}
return 0;
}
/** Translate <b>reason</b>, which came from a relay 'end' cell,
* into a static const string describing why the stream is closing.
* <b>reason</b> is -1 if no reason was provided.
*/
static const char *
connection_edge_end_reason_str(int reason)
{
switch (reason) {
case -1:
log_warn(LD_PROTOCOL,
"End cell arrived with length 0. Should be at least 1.");
return "MALFORMED";
case END_STREAM_REASON_MISC: return "misc error";
case END_STREAM_REASON_RESOLVEFAILED: return "resolve failed";
case END_STREAM_REASON_CONNECTREFUSED: return "connection refused";
case END_STREAM_REASON_EXITPOLICY: return "exit policy failed";
case END_STREAM_REASON_DESTROY: return "destroyed";
case END_STREAM_REASON_DONE: return "closed normally";
case END_STREAM_REASON_TIMEOUT: return "gave up (timeout)";
case END_STREAM_REASON_HIBERNATING: return "server is hibernating";
case END_STREAM_REASON_INTERNAL: return "internal error at server";
case END_STREAM_REASON_RESOURCELIMIT: return "server out of resources";
case END_STREAM_REASON_CONNRESET: return "connection reset";
case END_STREAM_REASON_TORPROTOCOL: return "Tor protocol error";
default:
log_warn(LD_PROTOCOL,"Reason for ending (%d) not recognized.",reason);
return "unknown";
}
}
/** Translate <b>reason</b> (as from a relay 'end' cell) into an
* appropriate SOCKS5 reply code.
*/
socks5_reply_status_t
connection_edge_end_reason_socks5_response(int reason)
{
switch (reason) {
case END_STREAM_REASON_MISC:
return SOCKS5_GENERAL_ERROR;
case END_STREAM_REASON_RESOLVEFAILED:
return SOCKS5_HOST_UNREACHABLE;
case END_STREAM_REASON_CONNECTREFUSED:
return SOCKS5_CONNECTION_REFUSED;
case END_STREAM_REASON_EXITPOLICY:
return SOCKS5_NOT_ALLOWED;
case END_STREAM_REASON_DESTROY:
return SOCKS5_GENERAL_ERROR;
case END_STREAM_REASON_DONE:
return SOCKS5_SUCCEEDED;
case END_STREAM_REASON_TIMEOUT:
return SOCKS5_TTL_EXPIRED;
case END_STREAM_REASON_RESOURCELIMIT:
return SOCKS5_GENERAL_ERROR;
case END_STREAM_REASON_HIBERNATING:
return SOCKS5_GENERAL_ERROR;
case END_STREAM_REASON_INTERNAL:
return SOCKS5_GENERAL_ERROR;
case END_STREAM_REASON_CONNRESET:
return SOCKS5_CONNECTION_REFUSED;
case END_STREAM_REASON_TORPROTOCOL:
return SOCKS5_GENERAL_ERROR;
case END_STREAM_REASON_ALREADY_SOCKS_REPLIED:
return SOCKS5_SUCCEEDED; /* never used */
case END_STREAM_REASON_CANT_ATTACH:
return SOCKS5_GENERAL_ERROR;
case END_STREAM_REASON_NET_UNREACHABLE:
return SOCKS5_NET_UNREACHABLE;
default:
log_warn(LD_PROTOCOL,"Reason for ending (%d) not recognized.",reason);
return SOCKS5_GENERAL_ERROR;
}
}
/* We need to use a few macros to deal with the fact that Windows
* decided that their sockets interface should be a permakludge.
* E_CASE is for errors where windows has both a EFOO and a WSAEFOO
* version, and S_CASE is for errors where windows has only a WSAEFOO
* version. (The E is for 'error', the S is for 'socket'). */
#ifdef MS_WINDOWS
#define E_CASE(s) case s: case WSA ## s
#define S_CASE(s) case WSA ## s
#else
#define E_CASE(s) case s
#define S_CASE(s) case s
#endif
/** Given an errno from a failed exit connection, return a reason code
* appropriate for use in a RELAY END cell.
*/
int
errno_to_end_reason(int e)
{
switch (e) {
case EPIPE:
return END_STREAM_REASON_DONE;
E_CASE(EBADF):
E_CASE(EFAULT):
E_CASE(EINVAL):
S_CASE(EISCONN):
S_CASE(ENOTSOCK):
S_CASE(EPROTONOSUPPORT):
S_CASE(EAFNOSUPPORT):
E_CASE(EACCES):
S_CASE(ENOTCONN):
S_CASE(ENETUNREACH):
return END_STREAM_REASON_INTERNAL;
S_CASE(ECONNREFUSED):
return END_STREAM_REASON_CONNECTREFUSED;
S_CASE(ECONNRESET):
return END_STREAM_REASON_CONNRESET;
S_CASE(ETIMEDOUT):
return END_STREAM_REASON_TIMEOUT;
S_CASE(ENOBUFS):
case ENOMEM:
case ENFILE:
E_CASE(EMFILE):
return END_STREAM_REASON_RESOURCELIMIT;
default:
log_info(LD_EXIT, "Didn't recognize errno %d (%s); telling the OP that "
"we are ending a stream for 'misc' reason.",
e, tor_socket_strerror(e));
return END_STREAM_REASON_MISC;
}
}
/** 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;
}
/** Called when we receive an END cell on a stream that isn't open yet.
* Arguments are as for connection_edge_process_relay_cell().
*/
static int
connection_edge_process_end_not_open(
relay_header_t *rh, cell_t *cell, circuit_t *circ,
connection_t *conn, crypt_path_t *layer_hint)
{
struct in_addr in;
routerinfo_t *exitrouter;
int reason = *(cell->payload+RELAY_HEADER_SIZE);
if (rh->length > 0 && edge_reason_is_retriable(reason) &&
conn->type == CONN_TYPE_AP) {
log_info(LD_APP,"Address '%s' refused due to '%s'. Considering retrying.",
safe_str(conn->socks_request->address),
connection_edge_end_reason_str(reason));
exitrouter =
router_get_by_digest(circ->build_state->chosen_exit->identity_digest);
switch (reason) {
case END_STREAM_REASON_EXITPOLICY:
if (rh->length >= 5) {
uint32_t addr = ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+1));
int ttl;
if (!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 (rh->length >= 9)
ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+5));
else
ttl = -1;
client_dns_set_addressmap(conn->socks_request->address, addr,
conn->chosen_exit_name, ttl);
}
/* check if he *ought* to have allowed it */
if (exitrouter &&
(rh->length < 5 ||
(tor_inet_aton(conn->socks_request->address, &in) &&
!conn->chosen_exit_name))) {
log_notice(LD_APP,
"Exitrouter '%s' seems to be more restrictive than its exit "
"policy. Not using this router as exit for now.",
exitrouter->nickname);
addr_policy_free(exitrouter->exit_policy);
exitrouter->exit_policy =
router_parse_addr_policy_from_string("reject *:*", -1);
}
/* rewrite it to an IP if we learned one. */
addressmap_rewrite(conn->socks_request->address,
sizeof(conn->socks_request->address));
if (connection_ap_detach_retriable(conn, circ) >= 0)
return 0;
/* else, conn will get closed below */
break;
case END_STREAM_REASON_RESOLVEFAILED:
case END_STREAM_REASON_MISC:
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);
tor_assert(circ->timestamp_dirty);
circ->timestamp_dirty -= get_options()->MaxCircuitDirtiness;
if (connection_ap_detach_retriable(conn, circ) >= 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) {
addr_policy_free(exitrouter->exit_policy);
exitrouter->exit_policy =
router_parse_addr_policy_from_string("reject *:*", -1);
}
if (connection_ap_detach_retriable(conn, circ) >= 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.",
connection_edge_end_reason_str(rh->length > 0 ? reason : -1));
if (conn->type == CONN_TYPE_AP) {
circuit_log_path(LOG_INFO,LD_APP,circ);
connection_mark_unattached_ap(conn, reason);
} else {
conn->has_sent_end = 1; /* we just got an 'end', don't need to send one */
connection_mark_for_close(conn);
}
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,
connection_t *conn, crypt_path_t *layer_hint)
{
if (rh->command == RELAY_COMMAND_END)
return connection_edge_process_end_not_open(rh, cell, circ, conn,
layer_hint);
if (conn->type == CONN_TYPE_AP && rh->command == RELAY_COMMAND_CONNECTED) {
if (conn->state != AP_CONN_STATE_CONNECT_WAIT) {
log_warn(LD_APP,"Got 'connected' while not in state connect_wait. "
"Dropping.");
return 0;
}
// log_fn(LOG_INFO,"Connected! Notifying application.");
conn->state = AP_CONN_STATE_OPEN;
log_info(LD_APP,"'connected' received after %d seconds.",
(int)(time(NULL) - conn->timestamp_lastread));
if (rh->length >= 4) {
uint32_t addr = ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE));
int ttl;
if (!addr) {
log_info(LD_APP,
"...but it claims the IP address was 0.0.0.0. Closing.");
connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL,
conn->cpath_layer);
connection_mark_unattached_ap(conn, END_STREAM_REASON_TORPROTOCOL);
return 0;
}
if (rh->length >= 8)
ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+4));
else
ttl = -1;
client_dns_set_addressmap(conn->socks_request->address, addr,
conn->chosen_exit_name, ttl);
}
circuit_log_path(LOG_INFO,LD_APP,circ);
connection_ap_handshake_socks_reply(conn, NULL, 0, SOCKS5_SUCCEEDED);
/* handle anything that might have queued */
if (connection_edge_package_raw_inbuf(conn, 1) < 0) {
/* (We already sent an end cell if possible) */
connection_mark_for_close(conn);
return 0;
}
return 0;
}
if (conn->type == CONN_TYPE_AP && rh->command == RELAY_COMMAND_RESOLVED) {
int ttl;
int answer_len;
if (conn->state != AP_CONN_STATE_RESOLVE_WAIT) {
log_warn(LD_APP,"Got a 'resolved' cell while not in state resolve_wait. "
"Dropping.");
return 0;
}
tor_assert(conn->socks_request->command == SOCKS_COMMAND_RESOLVE);
answer_len = cell->payload[RELAY_HEADER_SIZE+1];
if (rh->length < 2 || answer_len+2>rh->length) {
log_warn(LD_PROTOCOL, "Dropping malformed 'resolved' cell");
connection_mark_unattached_ap(conn, END_STREAM_REASON_TORPROTOCOL);
return 0;
}
if (rh->length >= answer_len+6)
ttl = (int)ntohl(get_uint32(cell->payload+RELAY_HEADER_SIZE+
2+answer_len));
else
ttl = -1;
connection_ap_handshake_socks_resolved(conn,
cell->payload[RELAY_HEADER_SIZE], /*answer_type*/
cell->payload[RELAY_HEADER_SIZE+1], /*answer_len*/
cell->payload+RELAY_HEADER_SIZE+2, /*answer*/
ttl);
connection_mark_unattached_ap(conn,
END_STREAM_REASON_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->state,
conn_state_to_string(conn->type, conn->state));
return 0; /* for forward compatibility, don't kill the circuit */
// connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL,
// conn->cpath_layer);
// 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,
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;
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.", num_seen);
if (rh.length > RELAY_PAYLOAD_SIZE) {
log_warn(LD_PROTOCOL,
"Relay cell length field too long. Closing circuit.");
return - END_CIRC_REASON_TORPROTOCOL;
}
/* 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(conn))
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:
if (layer_hint &&
circ->purpose != CIRCUIT_PURPOSE_S_REND_JOINED) {
log_warn(LD_APP,"relay begin request unsupported at AP. Dropping.");
return 0;
}
if (conn) {
log_warn(domain,"begin cell for known stream. Dropping.");
return 0;
}
connection_exit_begin_conn(cell, circ);
return 0;
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.");
connection_edge_end(conn, END_STREAM_REASON_TORPROTOCOL,
conn->cpath_layer);
connection_mark_for_close(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.");
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(cell->payload + RELAY_HEADER_SIZE,
rh.length, conn);
connection_edge_consider_sending_sendme(conn);
return 0;
case RELAY_COMMAND_END:
if (!conn) {
log_info(domain,"end cell (%s) dropped, unknown stream.",
connection_edge_end_reason_str(rh.length > 0 ?
*(char *)(cell->payload+RELAY_HEADER_SIZE) : -1));
return 0;
}
/* XXX add to this log_fn the exit node's nickname? */
log_info(domain,"%d: end cell (%s) for stream %d. Removing stream.",
conn->s,
connection_edge_end_reason_str(rh.length > 0 ?
*(char *)(cell->payload+RELAY_HEADER_SIZE) : -1),
conn->stream_id);
if (conn->socks_request && !conn->socks_request->has_finished)
log_warn(LD_BUG,
"Bug: open stream hasn't sent socks answer yet? Closing.");
#ifdef HALF_OPEN
conn->done_sending = 1;
shutdown(conn->s, 1); /* XXX check return; refactor NM */
if (conn->done_receiving) {
/* We just *got* an end; no reason to send one. */
conn->has_sent_end = 1;
connection_mark_for_close(conn);
conn->hold_open_until_flushed = 1;
}
#else
/* We just *got* an end; no reason to send one. */
conn->has_sent_end = 1;
if (!conn->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_for_close(conn);
conn->hold_open_until_flushed = 1;
}
#endif
return 0;
case RELAY_COMMAND_EXTEND:
if (conn) {
log_warn(domain,"'extend' for non-zero stream. Dropping.");
return 0;
}
return circuit_extend(cell, circ);
case RELAY_COMMAND_EXTENDED:
if (!layer_hint) {
log_warn(LD_PROTOCOL,
"'extended' unsupported at non-origin. Dropping.");
return 0;
}
log_debug(domain,"Got an extended cell! Yay.");
if ((reason = circuit_finish_handshake(circ, CELL_CREATED,
cell->payload+RELAY_HEADER_SIZE)) < 0) {
log_warn(domain,"circuit_finish_handshake failed.");
return reason;
}
if ((reason=circuit_send_next_onion_skin(circ))<0) {
log_info(domain,"circuit_send_next_onion_skin() failed.");
return reason;
}
return 0;
case RELAY_COMMAND_TRUNCATE:
if (layer_hint) {
log_warn(LD_APP,"'truncate' unsupported at origin. Dropping.");
return 0;
}
if (circ->n_conn) {
uint8_t reason = *(uint8_t*)(cell->payload + RELAY_HEADER_SIZE);
connection_or_send_destroy(circ->n_circ_id, circ->n_conn, reason);
circuit_set_circid_orconn(circ, 0, NULL, N_CONN_CHANGED);
}
log_debug(LD_EXIT, "Processed 'truncate', replying.");
{
char payload[1];
payload[0] = (char)END_CIRC_REASON_REQUESTED;
connection_edge_send_command(NULL, circ, RELAY_COMMAND_TRUNCATED,
payload, sizeof(payload), NULL);
}
return 0;
case RELAY_COMMAND_TRUNCATED:
if (!layer_hint) {
log_warn(LD_EXIT,"'truncated' unsupported at non-origin. Dropping.");
return 0;
}
circuit_truncated(circ, layer_hint);
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 (!conn) {
if (layer_hint) {
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 {
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;
}
conn->package_window += STREAMWINDOW_INCREMENT;
log_debug(domain,"stream-level sendme, packagewindow now %d.",
conn->package_window);
connection_start_reading(conn);
/* handle whatever might still be on the inbuf */
if (connection_edge_package_raw_inbuf(conn, 1) < 0) {
/* (We already sent an end cell if possible) */
connection_mark_for_close(conn);
return 0;
}
return 0;
case RELAY_COMMAND_RESOLVE:
if (layer_hint) {
log_warn(LD_APP,"resolve request unsupported at AP; dropping.");
return 0;
} else if (conn) {
log_warn(domain, "resolve request for known stream; dropping.");
return 0;
} else if (circ->purpose != CIRCUIT_PURPOSE_OR) {
log_warn(domain, "resolve request on circ with purpose %d; dropping",
circ->purpose);
return 0;
}
connection_exit_begin_resolve(cell, circ);
return 0;
case RELAY_COMMAND_RESOLVED:
if (conn) {
log_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, 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 */
}
uint64_t stats_n_data_cells_packaged = 0;
uint64_t stats_n_data_bytes_packaged = 0;
uint64_t stats_n_data_cells_received = 0;
uint64_t stats_n_data_bytes_received = 0;
/** While conn->inbuf has an entire relay payload of bytes on it,
* and the appropriate package windows aren't empty, grab a cell
* and send it down the circuit.
*
* Return -1 (and send a RELAY_END cell if necessary) if conn should
* be marked for close, else return 0.
*/
int
connection_edge_package_raw_inbuf(connection_t *conn, int package_partial)
{
size_t amount_to_process, length;
char payload[CELL_PAYLOAD_SIZE];
circuit_t *circ;
unsigned domain = conn->cpath_layer ? LD_APP : LD_EXIT;
tor_assert(conn);
tor_assert(!connection_speaks_cells(conn));
if (conn->marked_for_close) {
log_warn(LD_BUG,
"Bug: called on conn that's already marked for close at %s:%d.",
conn->marked_for_close_file, conn->marked_for_close);
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.");
return -1;
}
if (circuit_consider_stop_edge_reading(circ, conn->cpath_layer))
return 0;
if (conn->package_window <= 0) {
log_info(domain,"called with package_window %d. Skipping.",
conn->package_window);
connection_stop_reading(conn);
return 0;
}
amount_to_process = buf_datalen(conn->inbuf);
if (!amount_to_process)
return 0;
if (!package_partial && amount_to_process < RELAY_PAYLOAD_SIZE)
return 0;
if (amount_to_process > RELAY_PAYLOAD_SIZE) {
length = RELAY_PAYLOAD_SIZE;
} else {
length = amount_to_process;
}
stats_n_data_bytes_packaged += length;
stats_n_data_cells_packaged += 1;
connection_fetch_from_buf(payload, length, conn);
log_debug(domain,"(%d) Packaging %d bytes (%d waiting).", conn->s,
(int)length, (int)buf_datalen(conn->inbuf));
if (connection_edge_send_command(conn, circ, RELAY_COMMAND_DATA,
payload, length, conn->cpath_layer) < 0)
/* circuit got marked for close, don't continue, don't need to mark conn */
return 0;
if (!conn->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(conn->cpath_layer->package_window > 0);
conn->cpath_layer->package_window--;
}
if (--conn->package_window <= 0) { /* is it 0 after decrement? */
connection_stop_reading(conn);
log_debug(domain,"conn->package_window reached 0.");
circuit_consider_stop_edge_reading(circ, conn->cpath_layer);
return 0; /* don't process the inbuf any more */
}
log_debug(domain,"conn->package_window is now %d",conn->package_window);
/* 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, or when
* we've just finished flushing all bytes to 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(connection_t *conn)
{
circuit_t *circ;
if (connection_outbuf_too_full(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->cpath_layer?LD_APP:LD_EXIT,
"Outbuf %d, Queueing stream sendme.",
(int)conn->outbuf_flushlen);
conn->deliver_window += STREAMWINDOW_INCREMENT;
if (connection_edge_send_command(conn, circ, RELAY_COMMAND_SENDME,
NULL, 0, conn->cpath_layer) < 0) {
log_warn(LD_APP,"connection_edge_send_command failed. Returning.");
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)
{
log_debug(layer_hint?LD_APP:LD_EXIT,"resuming");
/* have to check both n_streams and p_streams, to handle rendezvous */
if (circuit_resume_edge_reading_helper(circ->n_streams, circ, layer_hint)
>= 0)
circuit_resume_edge_reading_helper(circ->p_streams, circ, layer_hint);
}
/** 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(connection_t *conn,
circuit_t *circ,
crypt_path_t *layer_hint)
{
for ( ; conn; conn=conn->next_stream) {
if (conn->marked_for_close)
continue;
if ((!layer_hint && conn->package_window > 0) ||
(layer_hint && conn->package_window > 0 &&
conn->cpath_layer == layer_hint)) {
connection_start_reading(conn);
/* handle whatever might still be on the inbuf */
if (connection_edge_package_raw_inbuf(conn, 1)<0) {
/* (We already sent an end cell if possible) */
connection_mark_for_close(conn);
continue;
}
/* 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;
}
}
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)
{
connection_t *conn = NULL;
unsigned domain = layer_hint ? LD_APP : LD_EXIT;
if (!layer_hint) {
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 = circ->n_streams; conn; conn=conn->next_stream)
connection_stop_reading(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 = circ->n_streams; conn; conn=conn->next_stream)
if (conn->cpath_layer == layer_hint)
connection_stop_reading(conn);
for (conn = circ->p_streams; conn; conn=conn->next_stream)
if (conn->cpath_layer == layer_hint)
connection_stop_reading(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,"Queueing circuit sendme.");
if (layer_hint)
layer_hint->deliver_window += CIRCWINDOW_INCREMENT;
else
circ->deliver_window += CIRCWINDOW_INCREMENT;
if (connection_edge_send_command(NULL, circ, RELAY_COMMAND_SENDME,
NULL, 0, layer_hint) < 0) {
log_warn(LD_CIRC,
"connection_edge_send_command failed. Circuit's closed.");
return; /* the circuit's closed, don't continue */
}
}
}