/* Copyright 2001 Matej Pfajfar.
* Copyright 2001-2004 Roger Dingledine.
* Copyright 2004 Roger Dingledine, Nick Mathewson. */
/* See LICENSE for licensing information */
/* $Id$ */
const char connection_edge_c_id[] = "$Id$";
/**
* \file connection_edge.c
* \brief Handle edge streams.
**/
#include "or.h"
#include "tree.h"
static struct addr_policy_t *socks_policy = NULL;
/* List of exit_redirect_t */
static smartlist_t *redirect_exit_list = NULL;
static int connection_ap_handshake_process_socks(connection_t *conn);
/** There was an EOF. Send an end and mark the connection for close.
*/
int connection_edge_reached_eof(connection_t *conn) {
#ifdef HALF_OPEN
/* eof reached; we're done reading, but we might want to write more. */
conn->done_receiving = 1;
shutdown(conn->s, 0); /* XXX check return, refactor NM */
if (conn->done_sending) {
connection_edge_end(conn, END_STREAM_REASON_DONE, conn->cpath_layer);
connection_mark_for_close(conn);
} else {
connection_edge_send_command(conn, circuit_get_by_conn(conn), RELAY_COMMAND_END,
NULL, 0, conn->cpath_layer);
}
return 0;
#else
if (buf_datalen(conn->inbuf)) {
/* it still has stuff to process. don't let it die yet. */
return 0;
}
log_fn(LOG_INFO,"conn (fd %d) reached eof (stream size %d). Closing.", conn->s, (int)conn->stream_size);
connection_edge_end(conn, END_STREAM_REASON_DONE, conn->cpath_layer);
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; /* just because we shouldn't read
doesn't mean we shouldn't write */
return 0;
#endif
}
/** Handle new bytes on conn->inbuf based on state:
* - If it's waiting for socks info, try to read another step of the
* socks handshake out of conn->inbuf.
* - If it's open, then package more relay cells from the stream.
* - Else, leave the bytes on inbuf alone for now.
*
* Mark and return -1 if there was an unexpected error with the conn,
* else return 0.
*/
int connection_edge_process_inbuf(connection_t *conn, int package_partial) {
tor_assert(conn);
tor_assert(conn->type == CONN_TYPE_AP || conn->type == CONN_TYPE_EXIT);
switch (conn->state) {
case AP_CONN_STATE_SOCKS_WAIT:
if (connection_ap_handshake_process_socks(conn) < 0) {
conn->has_sent_end = 1; /* no circ yet */
connection_mark_for_close(conn);
conn->hold_open_until_flushed = 1;
return -1;
}
return 0;
case AP_CONN_STATE_OPEN:
case EXIT_CONN_STATE_OPEN:
if (connection_edge_package_raw_inbuf(conn, package_partial) < 0) {
connection_edge_end(conn, END_STREAM_REASON_MISC, conn->cpath_layer);
connection_mark_for_close(conn);
return -1;
}
return 0;
case EXIT_CONN_STATE_CONNECTING:
case AP_CONN_STATE_RENDDESC_WAIT:
case AP_CONN_STATE_CIRCUIT_WAIT:
case AP_CONN_STATE_CONNECT_WAIT:
case AP_CONN_STATE_RESOLVE_WAIT:
log_fn(LOG_INFO,"data from edge while in '%s' state. Leaving it on buffer.",
conn_state_to_string[conn->type][conn->state]);
return 0;
}
log_fn(LOG_WARN,"Got unexpected state %d. Closing.",conn->state);
connection_edge_end(conn, END_STREAM_REASON_MISC, conn->cpath_layer);
connection_mark_for_close(conn);
return -1;
}
/** This edge needs to be closed, because its circuit has closed.
* Mark it for close and return 0.
*/
int connection_edge_destroy(uint16_t circ_id, connection_t *conn) {
tor_assert(conn->type == CONN_TYPE_AP || conn->type == CONN_TYPE_EXIT);
if (conn->marked_for_close)
return 0; /* already marked; probably got an 'end' */
log_fn(LOG_INFO,"CircID %d: At an edge. Marking connection for close.",
circ_id);
conn->has_sent_end = 1; /* we're closing the circuit, nothing to send to */
connection_mark_for_close(conn);
conn->hold_open_until_flushed = 1;
return 0;
}
/** Send a relay end cell from stream <b>conn</b> to conn's circuit,
* with a destination of cpath_layer. (If cpath_layer is NULL, the
* destination is the circuit's origin.) Mark the relay end cell as
* closing because of <b>reason</b>.
*
* Return -1 if this function has already been called on this conn,
* else return 0.
*/
int
connection_edge_end(connection_t *conn, char reason, crypt_path_t *cpath_layer)
{
char payload[5];
size_t payload_len=1;
circuit_t *circ;
if (conn->has_sent_end) {
log_fn(LOG_WARN,"It appears I've already sent the end. Are you calling me twice?");
return -1;
}
payload[0] = reason;
if (reason == END_STREAM_REASON_EXITPOLICY) {
/* this is safe even for rend circs, because they never fail
* because of exitpolicy */
set_uint32(payload+1, htonl(conn->addr));
payload_len += 4;
}
circ = circuit_get_by_conn(conn);
if (circ && !circ->marked_for_close) {
log_fn(LOG_DEBUG,"Marking conn (fd %d) and sending end.",conn->s);
connection_edge_send_command(conn, circ, RELAY_COMMAND_END,
payload, payload_len, cpath_layer);
} else {
log_fn(LOG_DEBUG,"Marking conn (fd %d); no circ to send end.",conn->s);
}
conn->has_sent_end = 1;
return 0;
}
/** Connection <b>conn</b> has finished writing and has no bytes left on
* its outbuf.
*
* If it's in state 'open', stop writing, consider responding with a
* sendme, and return.
* Otherwise, stop writing and return.
*
* If <b>conn</b> is broken, mark it for close and return -1, else
* return 0.
*/
int connection_edge_finished_flushing(connection_t *conn) {
tor_assert(conn);
tor_assert(conn->type == CONN_TYPE_AP || conn->type == CONN_TYPE_EXIT);
switch (conn->state) {
case AP_CONN_STATE_OPEN:
case EXIT_CONN_STATE_OPEN:
connection_stop_writing(conn);
connection_edge_consider_sending_sendme(conn);
return 0;
case AP_CONN_STATE_SOCKS_WAIT:
case AP_CONN_STATE_RENDDESC_WAIT:
case AP_CONN_STATE_CIRCUIT_WAIT:
case AP_CONN_STATE_CONNECT_WAIT:
connection_stop_writing(conn);
return 0;
default:
log_fn(LOG_WARN,"BUG: called in unexpected state %d.", conn->state);
return -1;
}
return 0;
}
/** Connected handler for exit connections: start writing pending
* data, deliver 'CONNECTED' relay cells as appropriate, and check
* any pending data that may have been received. */
int connection_edge_finished_connecting(connection_t *conn)
{
unsigned char connected_payload[4];
tor_assert(conn);
tor_assert(conn->type == CONN_TYPE_EXIT);
tor_assert(conn->state == EXIT_CONN_STATE_CONNECTING);
log_fn(LOG_INFO,"Exit connection to %s:%u established.",
conn->address,conn->port);
conn->state = EXIT_CONN_STATE_OPEN;
connection_watch_events(conn, POLLIN); /* stop writing, continue reading */
if (connection_wants_to_flush(conn)) /* in case there are any queued relay cells */
connection_start_writing(conn);
/* deliver a 'connected' relay cell back through the circuit. */
if (connection_edge_is_rendezvous_stream(conn)) {
if (connection_edge_send_command(conn, circuit_get_by_conn(conn),
RELAY_COMMAND_CONNECTED, NULL, 0, conn->cpath_layer) < 0)
return 0; /* circuit is closed, don't continue */
} else {
*(uint32_t*)connected_payload = htonl(conn->addr);
if (connection_edge_send_command(conn, circuit_get_by_conn(conn),
RELAY_COMMAND_CONNECTED, connected_payload, 4, conn->cpath_layer) < 0)
return 0; /* circuit is closed, don't continue */
}
tor_assert(conn->package_window > 0);
/* in case the server has written anything */
return connection_edge_process_inbuf(conn, 1);
}
/** How many times do we retry a general-purpose stream (detach it from
* one circuit and try another, after we wait a while with no 'connected'
* cell) before giving up?
*/
#define MAX_STREAM_RETRIES 4
/** Find all general-purpose AP streams waiting for a response that sent
* their begin/resolve cell >=15 seconds ago. Detach from their current circuit,
* and mark their current circuit as unsuitable for new streams. Then call
* connection_ap_handshake_attach_circuit() to attach to a new circuit (if
* available) or launch a new one.
*
* For rendezvous streams, simply give up after 45 seconds (with no
* retry attempt).
*/
void connection_ap_expire_beginning(void) {
connection_t **carray;
connection_t *conn;
circuit_t *circ;
int n, i;
time_t now = time(NULL);
or_options_t *options = get_options();
get_connection_array(&carray, &n);
for (i = 0; i < n; ++i) {
conn = carray[i];
if (conn->type != CONN_TYPE_AP)
continue;
if (conn->state != AP_CONN_STATE_RESOLVE_WAIT &&
conn->state != AP_CONN_STATE_CONNECT_WAIT)
continue;
if (now - conn->timestamp_lastread < 15)
continue;
conn->num_retries++;
circ = circuit_get_by_conn(conn);
if (!circ) { /* it's vanished? */
log_fn(LOG_INFO,"Conn is waiting, but lost its circ.");
connection_mark_for_close(conn);
continue;
}
if (circ->purpose == CIRCUIT_PURPOSE_C_REND_JOINED) {
if (now - conn->timestamp_lastread > 45) {
log_fn(LOG_WARN,"Rend stream is %d seconds late. Giving up.",
(int)(now - conn->timestamp_lastread));
connection_edge_end(conn, END_STREAM_REASON_TIMEOUT, conn->cpath_layer);
connection_mark_for_close(conn);
}
continue;
}
tor_assert(circ->purpose == CIRCUIT_PURPOSE_C_GENERAL);
if (conn->num_retries >= MAX_STREAM_RETRIES) {
log_fn(LOG_WARN,"Stream is %d seconds late. Giving up.",
15*conn->num_retries); /* XXX this number is not accurate */
circuit_log_path(LOG_WARN, circ);
connection_edge_end(conn, END_STREAM_REASON_TIMEOUT, conn->cpath_layer);
connection_mark_for_close(conn);
} else {
log_fn(LOG_NOTICE,"Stream is %d seconds late. Retrying.",
(int)(now - conn->timestamp_lastread));
circuit_log_path(LOG_WARN, circ);
/* send an end down the circuit */
connection_edge_end(conn, END_STREAM_REASON_TIMEOUT, conn->cpath_layer);
/* un-mark it as ending, since we're going to reuse it */
conn->has_sent_end = 0;
/* move it back into 'pending' state. */
conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
circuit_detach_stream(circ, conn);
/* kludge to make us not try this circuit again, yet to allow
* current streams on it to survive if they can: make it
* unattractive to use for new streams */
tor_assert(circ->timestamp_dirty);
circ->timestamp_dirty -= options->NewCircuitPeriod;
/* give our stream another 15 seconds to try */
conn->timestamp_lastread += 15;
/* attaching to a dirty circuit is fine */
if (connection_ap_handshake_attach_circuit(conn)<0) {
/* it will never work */
/* Don't need to send end -- we're not connected */
conn->has_sent_end = 1;
connection_mark_for_close(conn);
}
} /* end if max_retries */
} /* end for */
}
/** Tell any AP streams that are waiting for a new circuit that one is
* available.
*/
void connection_ap_attach_pending(void)
{
connection_t **carray;
connection_t *conn;
int n, i;
get_connection_array(&carray, &n);
for (i = 0; i < n; ++i) {
conn = carray[i];
if (conn->marked_for_close ||
conn->type != CONN_TYPE_AP ||
conn->state != AP_CONN_STATE_CIRCUIT_WAIT)
continue;
if (connection_ap_handshake_attach_circuit(conn) < 0) {
/* -1 means it will never work */
/* Don't send end; there is no 'other side' yet */
conn->has_sent_end = 1;
connection_mark_for_close(conn);
}
}
}
/** connection_edge_process_inbuf() found a conn in state
* socks_wait. See if conn->inbuf has the right bytes to proceed with
* the socks handshake.
*
* If the handshake is complete, and it's for a general circuit, then
* try to attach it to a circuit (or launch one as needed). If it's for
* a rendezvous circuit, then fetch a rendezvous descriptor first (or
* attach/launch a circuit if the rendezvous descriptor is already here
* and fresh enough).
*
* Return -1 if an unexpected error with conn (and it should be marked
* for close), else return 0.
*/
static int connection_ap_handshake_process_socks(connection_t *conn) {
socks_request_t *socks;
int sockshere;
hostname_type_t addresstype;
tor_assert(conn);
tor_assert(conn->type == CONN_TYPE_AP);
tor_assert(conn->state == AP_CONN_STATE_SOCKS_WAIT);
tor_assert(conn->socks_request);
socks = conn->socks_request;
log_fn(LOG_DEBUG,"entered.");
sockshere = fetch_from_buf_socks(conn->inbuf, socks);
if (sockshere == -1 || sockshere == 0) {
if (socks->replylen) { /* we should send reply back */
log_fn(LOG_DEBUG,"reply is already set for us. Using it.");
connection_ap_handshake_socks_reply(conn, socks->reply, socks->replylen, 0);
socks->replylen = 0; /* zero it out so we can do another round of negotiation */
} else if (sockshere == -1) { /* send normal reject */
log_fn(LOG_WARN,"Fetching socks handshake failed. Closing.");
connection_ap_handshake_socks_reply(conn, NULL, 0, -1);
} else {
log_fn(LOG_DEBUG,"socks handshake not all here yet.");
}
if (sockshere == -1)
socks->has_finished = 1;
return sockshere;
} /* else socks handshake is done, continue processing */
if (socks->command == SOCKS_COMMAND_RESOLVE) {
uint32_t answer;
/* Reply to resolves immediately if we can. */
if (strlen(socks->address) > RELAY_PAYLOAD_SIZE) {
log_fn(LOG_WARN,"Address to be resolved is too large. Failing.");
connection_ap_handshake_socks_resolved(conn,RESOLVED_TYPE_ERROR,0,NULL);
return -1;
}
answer = htonl(client_dns_lookup_entry(socks->address));
if (answer) {
connection_ap_handshake_socks_resolved(conn,RESOLVED_TYPE_IPV4,4,
(char*)&answer);
conn->has_sent_end = 1;
connection_mark_for_close(conn);
conn->hold_open_until_flushed = 1;
return 0;
}
}
/* Parse the address provided by SOCKS. Modify it in-place if it
* specifies a hidden-service (.onion) or particular exit node (.exit).
*/
addresstype = parse_extended_hostname(socks->address);
if (addresstype == EXIT_HOSTNAME) {
/* .exit -- modify conn to specify the exit node. */
char *s = strrchr(socks->address,'.');
if (!s || s[1] == '\0') {
log_fn(LOG_WARN,"Malformed address '%s.exit'. Refusing.", socks->address);
return -1;
}
conn->chosen_exit_name = tor_strdup(s+1);
*s = 0;
}
if (addresstype != ONION_HOSTNAME) {
/* not a hidden-service request (i.e. normal or .exit) */
if (socks->command == SOCKS_COMMAND_CONNECT && socks->port == 0) {
log_fn(LOG_WARN,"Application asked to connect to port 0. Refusing.");
return -1;
}
conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
return connection_ap_handshake_attach_circuit(conn);
} else {
/* it's a hidden-service request */
rend_cache_entry_t *entry;
int r;
if (socks->command == SOCKS_COMMAND_RESOLVE) {
/* if it's a resolve request, fail it right now, rather than
* building all the circuits and then realizing it won't work. */
log_fn(LOG_WARN,"Resolve requests to hidden services not allowed. Failing.");
connection_ap_handshake_socks_resolved(conn,RESOLVED_TYPE_ERROR,0,NULL);
return -1;
}
strlcpy(conn->rend_query, socks->address, sizeof(conn->rend_query));
log_fn(LOG_INFO,"Got a hidden service request for ID '%s'", conn->rend_query);
/* see if we already have it cached */
r = rend_cache_lookup_entry(conn->rend_query, &entry);
if (r<0) {
log_fn(LOG_WARN,"Invalid service descriptor %s", conn->rend_query);
return -1;
}
if (r==0) {
conn->state = AP_CONN_STATE_RENDDESC_WAIT;
log_fn(LOG_INFO, "Unknown descriptor %s. Fetching.", conn->rend_query);
rend_client_refetch_renddesc(conn->rend_query);
return 0;
}
if (r>0) {
#define NUM_SECONDS_BEFORE_REFETCH (60*15)
if (time(NULL) - entry->received < NUM_SECONDS_BEFORE_REFETCH) {
conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
log_fn(LOG_INFO, "Descriptor is here and fresh enough. Great.");
return connection_ap_handshake_attach_circuit(conn);
} else {
conn->state = AP_CONN_STATE_RENDDESC_WAIT;
log_fn(LOG_INFO, "Stale descriptor %s. Refetching.", conn->rend_query);
rend_client_refetch_renddesc(conn->rend_query);
return 0;
}
}
}
return 0; /* unreached but keeps the compiler happy */
}
/** Iterate over the two bytes of stream_id until we get one that is not
* already in use; return it. Return 0 if can't get a unique stream_id.
*/
static uint16_t get_unique_stream_id_by_circ(circuit_t *circ) {
connection_t *tmpconn;
uint16_t test_stream_id;
uint32_t attempts=0;
again:
test_stream_id = circ->next_stream_id++;
if (++attempts > 1<<16) {
/* Make sure we don't loop forever if all stream_id's are used. */
log_fn(LOG_WARN,"No unused stream IDs. Failing.");
return 0;
}
if (test_stream_id == 0)
goto again;
for (tmpconn = circ->p_streams; tmpconn; tmpconn=tmpconn->next_stream)
if (tmpconn->stream_id == test_stream_id)
goto again;
return test_stream_id;
}
/** Write a relay begin cell, using destaddr and destport from ap_conn's
* socks_request field, and send it down circ.
*
* If ap_conn is broken, mark it for close and return -1. Else return 0.
*/
int connection_ap_handshake_send_begin(connection_t *ap_conn, circuit_t *circ)
{
char payload[CELL_PAYLOAD_SIZE];
int payload_len;
struct in_addr in;
const char *string_addr;
tor_assert(ap_conn->type == CONN_TYPE_AP);
tor_assert(ap_conn->state == AP_CONN_STATE_CIRCUIT_WAIT);
tor_assert(ap_conn->socks_request);
ap_conn->stream_id = get_unique_stream_id_by_circ(circ);
if (ap_conn->stream_id==0) {
/* Don't send end: there is no 'other side' yet */
ap_conn->has_sent_end = 1;
connection_mark_for_close(ap_conn);
circuit_mark_for_close(circ);
return -1;
}
if (circ->purpose == CIRCUIT_PURPOSE_C_GENERAL) {
in.s_addr = htonl(client_dns_lookup_entry(ap_conn->socks_request->address));
string_addr = in.s_addr ? inet_ntoa(in) : NULL;
tor_snprintf(payload,RELAY_PAYLOAD_SIZE,
"%s:%d",
string_addr ? string_addr : ap_conn->socks_request->address,
ap_conn->socks_request->port);
} else {
tor_snprintf(payload,RELAY_PAYLOAD_SIZE,
":%d", ap_conn->socks_request->port);
}
payload_len = strlen(payload)+1;
log_fn(LOG_DEBUG,"Sending relay cell to begin stream %d.",ap_conn->stream_id);
if (connection_edge_send_command(ap_conn, circ, RELAY_COMMAND_BEGIN,
payload, payload_len, ap_conn->cpath_layer) < 0)
return -1; /* circuit is closed, don't continue */
ap_conn->package_window = STREAMWINDOW_START;
ap_conn->deliver_window = STREAMWINDOW_START;
ap_conn->state = AP_CONN_STATE_CONNECT_WAIT;
log_fn(LOG_INFO,"Address/port sent, ap socket %d, n_circ_id %d",ap_conn->s,circ->n_circ_id);
control_event_stream_status(ap_conn, STREAM_EVENT_SENT_CONNECT);
return 0;
}
/** Write a relay resolve cell, using destaddr and destport from ap_conn's
* socks_request field, and send it down circ.
*
* If ap_conn is broken, mark it for close and return -1. Else return 0.
*/
int connection_ap_handshake_send_resolve(connection_t *ap_conn, circuit_t *circ)
{
int payload_len;
const char *string_addr;
tor_assert(ap_conn->type == CONN_TYPE_AP);
tor_assert(ap_conn->state == AP_CONN_STATE_CIRCUIT_WAIT);
tor_assert(ap_conn->socks_request);
tor_assert(ap_conn->socks_request->command == SOCKS_COMMAND_RESOLVE);
tor_assert(circ->purpose == CIRCUIT_PURPOSE_C_GENERAL);
ap_conn->stream_id = get_unique_stream_id_by_circ(circ);
if (ap_conn->stream_id==0) {
/* Don't send end: there is no 'other side' yet */
ap_conn->has_sent_end = 1;
connection_mark_for_close(ap_conn);
circuit_mark_for_close(circ);
return -1;
}
string_addr = ap_conn->socks_request->address;
payload_len = strlen(string_addr);
tor_assert(strlen(string_addr) <= RELAY_PAYLOAD_SIZE);
log_fn(LOG_DEBUG,"Sending relay cell to begin stream %d.",ap_conn->stream_id);
if (connection_edge_send_command(ap_conn, circ, RELAY_COMMAND_RESOLVE,
string_addr, payload_len, ap_conn->cpath_layer) < 0)
return -1; /* circuit is closed, don't continue */
ap_conn->state = AP_CONN_STATE_RESOLVE_WAIT;
log_fn(LOG_INFO,"Address sent for resolve, ap socket %d, n_circ_id %d",ap_conn->s,circ->n_circ_id);
control_event_stream_status(ap_conn, STREAM_EVENT_SENT_RESOLVE);
return 0;
}
/** Make an AP connection_t, do a socketpair and attach one side
* to the conn, connection_add it, initialize it to circuit_wait,
* and call connection_ap_handshake_attach_circuit(conn) on it.
*
* Return the other end of the socketpair, or -1 if error.
*/
int connection_ap_make_bridge(char *address, uint16_t port) {
int fd[2];
connection_t *conn;
log_fn(LOG_INFO,"Making AP bridge to %s:%d ...",address,port);
if (tor_socketpair(AF_UNIX, SOCK_STREAM, 0, fd) < 0) {
log(LOG_WARN,"Couldn't construct socketpair (%s). Network down? Delaying.",
tor_socket_strerror(tor_socket_errno(-1)));
return -1;
}
set_socket_nonblocking(fd[0]);
set_socket_nonblocking(fd[1]);
conn = connection_new(CONN_TYPE_AP);
conn->s = fd[0];
/* populate conn->socks_request */
/* leave version at zero, so the socks_reply is empty */
conn->socks_request->socks_version = 0;
conn->socks_request->has_finished = 0; /* waiting for 'connected' */
strlcpy(conn->socks_request->address, address,
sizeof(conn->socks_request->address));
conn->socks_request->port = port;
conn->socks_request->command = SOCKS_COMMAND_CONNECT;
conn->address = tor_strdup("(local bridge)");
conn->addr = 0;
conn->port = 0;
if (connection_add(conn) < 0) { /* no space, forget it */
connection_free(conn); /* this closes fd[0] */
tor_close_socket(fd[1]);
return -1;
}
conn->state = AP_CONN_STATE_CIRCUIT_WAIT;
connection_start_reading(conn);
/* attaching to a dirty circuit is fine */
if (connection_ap_handshake_attach_circuit(conn) < 0) {
conn->has_sent_end = 1; /* no circ to send to */
connection_mark_for_close(conn);
tor_close_socket(fd[1]);
return -1;
}
log_fn(LOG_INFO,"... AP bridge created and connected.");
return fd[1];
}
/* DOCDOC */
void connection_ap_handshake_socks_resolved(connection_t *conn,
int answer_type,
size_t answer_len,
const char *answer)
{
char buf[256];
size_t replylen;
if (answer_type == RESOLVED_TYPE_IPV4) {
uint32_t a = get_uint32(answer);
if (a)
client_dns_set_entry(conn->socks_request->address, ntohl(a));
}
if (conn->socks_request->socks_version == 4) {
buf[0] = 0x00; /* version */
if (answer_type == RESOLVED_TYPE_IPV4 && answer_len == 4) {
buf[1] = 90; /* "Granted" */
set_uint16(buf+2, 0);
memcpy(buf+4, answer, 4); /* address */
replylen = SOCKS4_NETWORK_LEN;
} else {
buf[1] = 91; /* "error" */
memset(buf+2, 0, 6);
replylen = SOCKS4_NETWORK_LEN;
}
} else {
/* SOCKS5 */
buf[0] = 0x05; /* version */
if (answer_type == RESOLVED_TYPE_IPV4 && answer_len == 4) {
buf[1] = 0; /* succeeded */
buf[2] = 0; /* reserved */
buf[3] = 0x01; /* IPv4 address type */
memcpy(buf+4, answer, 4); /* address */
set_uint16(buf+8, 0); /* port == 0. */
replylen = 10;
} else if (answer_type == RESOLVED_TYPE_IPV6 && answer_len == 16) {
buf[1] = 0; /* succeeded */
buf[2] = 0; /* reserved */
buf[3] = 0x04; /* IPv6 address type */
memcpy(buf+4, answer, 16); /* address */
set_uint16(buf+20, 0); /* port == 0. */
replylen = 22;
} else {
buf[1] = 0x04; /* host unreachable */
memset(buf+2, 0, 8);
replylen = 10;
}
}
connection_ap_handshake_socks_reply(conn, buf, replylen,
(answer_type == RESOLVED_TYPE_IPV4 ||
answer_type == RESOLVED_TYPE_IPV6) ? 1 : -1);
conn->socks_request->has_finished = 1;
}
/** Send a socks reply to stream <b>conn</b>, using the appropriate
* socks version, etc.
*
* Status can be 1 (succeeded), -1 (failed), or 0 (not sure yet).
*
* If <b>reply</b> is defined, then write <b>replylen</b> bytes of it
* to conn and return, else reply based on <b>status</b>.
*
* If <b>reply</b> is undefined, <b>status</b> can't be 0.
*/
void connection_ap_handshake_socks_reply(connection_t *conn, char *reply,
size_t replylen, int status) {
char buf[256];
if (status) /* it's either 1 or -1 */
control_event_stream_status(conn,
status==1 ? STREAM_EVENT_SUCCEEDED : STREAM_EVENT_FAILED);
if (replylen) { /* we already have a reply in mind */
connection_write_to_buf(reply, replylen, conn);
return;
}
tor_assert(conn->socks_request);
tor_assert(status == 1 || status == -1);
if (conn->socks_request->socks_version == 4) {
memset(buf,0,SOCKS4_NETWORK_LEN);
#define SOCKS4_GRANTED 90
#define SOCKS4_REJECT 91
buf[1] = (status==1 ? SOCKS4_GRANTED : SOCKS4_REJECT);
/* leave version, destport, destip zero */
connection_write_to_buf(buf, SOCKS4_NETWORK_LEN, conn);
}
if (conn->socks_request->socks_version == 5) {
buf[0] = 5; /* version 5 */
#define SOCKS5_SUCCESS 0
#define SOCKS5_GENERIC_ERROR 1
buf[1] = status==1 ? SOCKS5_SUCCESS : SOCKS5_GENERIC_ERROR;
buf[2] = 0;
buf[3] = 1; /* ipv4 addr */
memset(buf+4,0,6); /* Set external addr/port to 0.
The spec doesn't seem to say what to do here. -RD */
connection_write_to_buf(buf,10,conn);
}
/* If socks_version isn't 4 or 5, don't send anything.
* This can happen in the case of AP bridges. */
return;
}
/** A relay 'begin' cell has arrived, and either we are an exit hop
* for the circuit, or we are the origin and it is a rendezvous begin.
*
* Launch a new exit connection and initialize things appropriately.
*
* If it's a rendezvous stream, call connection_exit_connect() on
* it.
*
* For general streams, call dns_resolve() on it first, and only call
* connection_exit_connect() if the dns answer is already known.
*
* Note that we don't call connection_add() on the new stream! We wait
* for connection_exit_connect() to do that.
*
* Return -1 if we want to tear down <b>circ</b>. Else return 0.
*/
int connection_exit_begin_conn(cell_t *cell, circuit_t *circ) {
connection_t *n_stream;
relay_header_t rh;
char *address=NULL;
uint16_t port;
assert_circuit_ok(circ);
relay_header_unpack(&rh, cell->payload);
/* XXX currently we don't send an end cell back if we drop the
* begin because it's malformed.
*/
if (!memchr(cell->payload+RELAY_HEADER_SIZE, 0, rh.length)) {
log_fn(LOG_WARN,"relay begin cell has no \\0. Dropping.");
return 0;
}
if (parse_addr_port(cell->payload+RELAY_HEADER_SIZE,&address,NULL,&port)<0) {
log_fn(LOG_WARN,"Unable to parse addr:port in relay begin cell. Dropping.");
return 0;
}
if (port==0) {
log_fn(LOG_WARN,"Missing port in relay begin cell. Dropping.");
tor_free(address);
return 0;
}
log_fn(LOG_DEBUG,"Creating new exit connection.");
n_stream = connection_new(CONN_TYPE_EXIT);
n_stream->purpose = EXIT_PURPOSE_CONNECT;
n_stream->stream_id = rh.stream_id;
n_stream->port = port;
/* leave n_stream->s at -1, because it's not yet valid */
n_stream->package_window = STREAMWINDOW_START;
n_stream->deliver_window = STREAMWINDOW_START;
if (circ->purpose == CIRCUIT_PURPOSE_S_REND_JOINED) {
log_fn(LOG_DEBUG,"begin is for rendezvous. configuring stream.");
n_stream->address = tor_strdup("(rendezvous)");
n_stream->state = EXIT_CONN_STATE_CONNECTING;
strlcpy(n_stream->rend_query, circ->rend_query,
sizeof(n_stream->rend_query));
tor_assert(connection_edge_is_rendezvous_stream(n_stream));
assert_circuit_ok(circ);
if (rend_service_set_connection_addr_port(n_stream, circ) < 0) {
log_fn(LOG_INFO,"Didn't find rendezvous service (port %d)",n_stream->port);
connection_edge_end(n_stream, END_STREAM_REASON_EXITPOLICY, n_stream->cpath_layer);
connection_free(n_stream);
circuit_mark_for_close(circ); /* knock the whole thing down, somebody screwed up */
tor_free(address);
return 0;
}
assert_circuit_ok(circ);
log_fn(LOG_DEBUG,"Finished assigning addr/port");
n_stream->cpath_layer = circ->cpath->prev; /* link it */
/* add it into the linked list of n_streams on this circuit */
n_stream->next_stream = circ->n_streams;
circ->n_streams = n_stream;
assert_circuit_ok(circ);
connection_exit_connect(n_stream);
tor_free(address);
return 0;
}
n_stream->address = address;
n_stream->state = EXIT_CONN_STATE_RESOLVEFAILED;
/* default to failed, change in dns_resolve if it turns out not to fail */
if (we_are_hibernating()) {
connection_edge_end(n_stream, END_STREAM_REASON_EXITPOLICY, n_stream->cpath_layer);
connection_free(n_stream);
}
/* send it off to the gethostbyname farm */
switch (dns_resolve(n_stream)) {
case 1: /* resolve worked */
/* add it into the linked list of n_streams on this circuit */
n_stream->next_stream = circ->n_streams;
circ->n_streams = n_stream;
assert_circuit_ok(circ);
connection_exit_connect(n_stream);
return 0;
case -1: /* resolve failed */
log_fn(LOG_INFO,"Resolve failed (%s).", n_stream->address);
connection_edge_end(n_stream, END_STREAM_REASON_RESOLVEFAILED, n_stream->cpath_layer);
connection_free(n_stream);
break;
case 0: /* resolve added to pending list */
/* add it into the linked list of resolving_streams on this circuit */
n_stream->next_stream = circ->resolving_streams;
circ->resolving_streams = n_stream;
assert_circuit_ok(circ);
;
}
return 0;
}
/**
* Called when we receive a RELAY_RESOLVE cell 'cell' along the circuit 'circ';
* begin resolving the hostname, and (eventually) reply with a RESOLVED cell.
*/
int connection_exit_begin_resolve(cell_t *cell, circuit_t *circ) {
connection_t *dummy_conn;
relay_header_t rh;
assert_circuit_ok(circ);
relay_header_unpack(&rh, cell->payload);
/* This 'dummy_conn' only exists to remember the stream ID
* associated with the resolve request; and to make the
* implementation of dns.c more uniform. (We really only need to
* remember the circuit, the stream ID, and the hostname to be
* resolved; but if we didn't store them in a connection like this,
* the housekeeping in dns.c would get way more complicated.)
*/
dummy_conn = connection_new(CONN_TYPE_EXIT);
dummy_conn->stream_id = rh.stream_id;
dummy_conn->address = tor_strndup(cell->payload+RELAY_HEADER_SIZE,
rh.length);
dummy_conn->port = 0;
dummy_conn->state = EXIT_CONN_STATE_RESOLVEFAILED;
dummy_conn->purpose = EXIT_PURPOSE_RESOLVE;
dummy_conn->next_stream = circ->resolving_streams;
circ->resolving_streams = dummy_conn;
/* send it off to the gethostbyname farm */
switch (dns_resolve(dummy_conn)) {
case 1: /* The result was cached; a resolved cell was sent. */
case -1:
circuit_detach_stream(circuit_get_by_conn(dummy_conn), dummy_conn);
connection_free(dummy_conn);
return 0;
case 0: /* resolve added to pending list */
assert_circuit_ok(circ);
;
}
return 0;
}
/** Connect to conn's specified addr and port. If it worked, conn
* has now been added to the connection_array.
*
* Send back a connected cell. Include the resolved IP of the destination
* address, but <em>only</em> if it's a general exit stream. (Rendezvous
* streams must not reveal what IP they connected to.)
*/
void
connection_exit_connect(connection_t *conn) {
unsigned char connected_payload[4];
uint32_t addr;
uint16_t port;
if (!connection_edge_is_rendezvous_stream(conn) &&
router_compare_to_my_exit_policy(conn) == ADDR_POLICY_REJECTED) {
log_fn(LOG_INFO,"%s:%d failed exit policy. Closing.", conn->address, conn->port);
connection_edge_end(conn, END_STREAM_REASON_EXITPOLICY, conn->cpath_layer);
circuit_detach_stream(circuit_get_by_conn(conn), conn);
connection_free(conn);
return;
}
addr = conn->addr;
port = conn->port;
if (redirect_exit_list) {
SMARTLIST_FOREACH(redirect_exit_list, exit_redirect_t *, r,
{
if ((addr&r->mask)==(r->addr&r->mask) &&
(r->port_min <= port) && (port <= r->port_max)) {
struct in_addr in;
if (r->is_redirect) {
addr = r->addr_dest;
port = r->port_dest;
in.s_addr = htonl(addr);
log_fn(LOG_DEBUG, "Redirecting connection from %s:%d to %s:%d",
conn->address, conn->port, inet_ntoa(in), port);
}
break;
}
});
}
log_fn(LOG_DEBUG,"about to try connecting");
switch (connection_connect(conn, conn->address, addr, port)) {
case -1:
connection_edge_end(conn, END_STREAM_REASON_CONNECTFAILED, conn->cpath_layer);
circuit_detach_stream(circuit_get_by_conn(conn), conn);
connection_free(conn);
return;
case 0:
conn->state = EXIT_CONN_STATE_CONNECTING;
connection_watch_events(conn, POLLOUT | POLLIN | POLLERR);
/* writable indicates finish, readable indicates broken link,
error indicates broken link in windowsland. */
return;
/* case 1: fall through */
}
conn->state = EXIT_CONN_STATE_OPEN;
if (connection_wants_to_flush(conn)) { /* in case there are any queued data cells */
log_fn(LOG_WARN,"tell roger: newly connected conn had data waiting!");
// connection_start_writing(conn);
}
connection_watch_events(conn, POLLIN);
/* also, deliver a 'connected' cell back through the circuit. */
if (connection_edge_is_rendezvous_stream(conn)) { /* rendezvous stream */
/* don't send an address back! */
connection_edge_send_command(conn, circuit_get_by_conn(conn), RELAY_COMMAND_CONNECTED,
NULL, 0, conn->cpath_layer);
} else { /* normal stream */
/* This must be the original address, not the redirected address. */
*(uint32_t*)connected_payload = htonl(conn->addr);
connection_edge_send_command(conn, circuit_get_by_conn(conn), RELAY_COMMAND_CONNECTED,
connected_payload, 4, conn->cpath_layer);
}
}
/** Return 1 if <b>conn</b> is a rendezvous stream, or 0 if
* it is a general stream.
*/
int connection_edge_is_rendezvous_stream(connection_t *conn) {
tor_assert(conn);
if (*conn->rend_query) /* XXX */
return 1;
return 0;
}
/** Return 1 if router <b>exit</b> might allow stream <b>conn</b>
* to exit from it, or 0 if it definitely will not allow it.
* (We might be uncertain if conn's destination address has not yet been
* resolved.)
*/
int connection_ap_can_use_exit(connection_t *conn, routerinfo_t *exit)
{
uint32_t addr;
tor_assert(conn);
tor_assert(conn->type == CONN_TYPE_AP);
tor_assert(conn->socks_request);
tor_assert(exit);
log_fn(LOG_DEBUG,"considering nickname %s, for address %s / port %d:",
exit->nickname, conn->socks_request->address,
conn->socks_request->port);
/* If a particular exit node has been requested for the new connection,
* make sure the exit node of the existing circuit matches exactly.
*/
if (conn->chosen_exit_name) {
if (router_get_by_nickname(conn->chosen_exit_name) != exit) {
/* doesn't match */
log_fn(LOG_DEBUG,"Requested node '%s', considering node '%s'. No.",
conn->chosen_exit_name, exit->nickname);
return 0;
}
}
if (conn->socks_request->command == SOCKS_COMMAND_RESOLVE) {
/* 0.0.8 servers have buggy resolve support. */
if (!tor_version_as_new_as(exit->platform, "0.0.9pre1"))
return 0;
} else {
addr = client_dns_lookup_entry(conn->socks_request->address);
if (router_compare_addr_to_addr_policy(addr, conn->socks_request->port,
exit->exit_policy) < 0)
return 0;
}
return 1;
}
/** A helper function for socks_policy_permits_address() below.
*
* Parse options->SocksPolicy in the same way that the exit policy
* is parsed, and put the processed version in &socks_policy.
* Ignore port specifiers.
*/
void
parse_socks_policy(void)
{
struct addr_policy_t *n;
if (socks_policy) {
addr_policy_free(socks_policy);
socks_policy = NULL;
}
config_parse_addr_policy(get_options()->SocksPolicy, &socks_policy);
/* ports aren't used. */
for (n=socks_policy; n; n = n->next) {
n->prt_min = 1;
n->prt_max = 65535;
}
}
/** Return 1 if <b>addr</b> is permitted to connect to our socks port,
* based on <b>socks_policy</b>. Else return 0.
*/
int socks_policy_permits_address(uint32_t addr)
{
int a;
if (!socks_policy) /* 'no socks policy' means 'accept' */
return 1;
a = router_compare_addr_to_addr_policy(addr, 1, socks_policy);
if (a==-1)
return 0;
else if (a==0)
return 1;
tor_assert(a==1);
log_fn(LOG_WARN, "Got unexpected 'maybe' answer from socks policy");
return 0;
}
/* ***** Client DNS code ***** */
/* XXX Perhaps this should get merged with the dns.c code somehow. */
/* XXX But we can't just merge them, because then nodes that act as
* both OR and OP could be attacked: people could rig the dns cache
* by answering funny things to stream begin requests, and later
* other clients would reuse those funny addr's. Hm.
*/
/** A client-side struct to remember the resolved IP (addr) for
* a given address. These structs make up a tree, with client_dns_map
* below as its root.
*/
struct client_dns_entry {
uint32_t addr; /**< The resolved IP of this entry. */
time_t expires; /**< At what second does addr expire? */
int n_failures; /**< How many times has this entry failed to resolve so far? */
};
/** How many elements are in the client dns cache currently? */
static int client_dns_size = 0;
/** The tree of client-side cached DNS resolves. */
static strmap_t *client_dns_map = NULL;
/** Initialize client_dns_map and client_dns_size. */
void client_dns_init(void) {
client_dns_map = strmap_new();
client_dns_size = 0;
}
/** Return the client_dns_entry that corresponds to <b>address</b>.
* If it's not there, allocate and return a new entry for <b>address</b>.
*/
static struct client_dns_entry *
_get_or_create_ent(const char *address)
{
struct client_dns_entry *ent;
ent = strmap_get_lc(client_dns_map,address);
if (!ent) {
ent = tor_malloc_zero(sizeof(struct client_dns_entry));
ent->expires = time(NULL)+MAX_DNS_ENTRY_AGE;
strmap_set_lc(client_dns_map,address,ent);
++client_dns_size;
}
return ent;
}
/** Return the IP associated with <b>address</b>, if we know it
* and it's still fresh enough. Otherwise return 0.
*/
uint32_t client_dns_lookup_entry(const char *address)
{
struct client_dns_entry *ent;
struct in_addr in;
time_t now;
tor_assert(address);
if (tor_inet_aton(address, &in)) {
log_fn(LOG_DEBUG, "Using static address %s (%08lX)", address,
(unsigned long)ntohl(in.s_addr));
return ntohl(in.s_addr);
}
ent = strmap_get_lc(client_dns_map,address);
if (!ent || !ent->addr) {
log_fn(LOG_DEBUG, "No entry found for address %s", address);
return 0;
} else {
now = time(NULL);
if (ent->expires < now) {
log_fn(LOG_DEBUG, "Expired entry found for address %s", address);
strmap_remove_lc(client_dns_map,address);
tor_free(ent);
--client_dns_size;
return 0;
}
in.s_addr = htonl(ent->addr);
log_fn(LOG_DEBUG, "Found cached entry for address %s: %s", address,
inet_ntoa(in));
return ent->addr;
}
}
/** An attempt to resolve <b>address</b> failed at some OR.
* Increment the number of resolve failures we have on record
* for it, and then return that number.
*/
int client_dns_incr_failures(const char *address)
{
struct client_dns_entry *ent;
ent = _get_or_create_ent(address);
++ent->n_failures;
log_fn(LOG_DEBUG,"Address %s now has %d resolve failures.",
address, ent->n_failures);
return ent->n_failures;
}
/** Record the fact that <b>address</b> resolved to <b>val</b>.
* We can now use this in subsequent streams in client_dns_lookup_entry(),
* so we can more correctly choose a router that will allow <b>address</b>
* to exit from him.
*/
void client_dns_set_entry(const char *address, uint32_t val)
{
struct client_dns_entry *ent;
struct in_addr in;
time_t now;
tor_assert(address);
tor_assert(val);
if (tor_inet_aton(address, &in))
return;
now = time(NULL);
ent = _get_or_create_ent(address);
in.s_addr = htonl(val);
log_fn(LOG_DEBUG, "Updating entry for address %s: %s", address,
inet_ntoa(in));
ent->addr = val;
ent->expires = now+MAX_DNS_ENTRY_AGE;
ent->n_failures = 0;
}
/** A helper function for client_dns_clean() below. If ent is too old,
* then remove it from the tree and return NULL, else return ent.
*/
static void* _remove_if_expired(const char *addr,
struct client_dns_entry *ent,
time_t *nowp)
{
if (ent->expires < *nowp) {
--client_dns_size;
tor_free(ent);
return NULL;
} else {
return ent;
}
}
/** Clean out entries from the client-side DNS cache that were
* resolved long enough ago that they are no longer valid.
*/
void client_dns_clean(void)
{
time_t now;
if (!client_dns_size)
return;
now = time(NULL);
strmap_foreach(client_dns_map, (strmap_foreach_fn)_remove_if_expired, &now);
}
/** Make connection redirection follow the provided list of
* exit_redirect_t */
void
set_exit_redirects(smartlist_t *lst)
{
if (redirect_exit_list) {
SMARTLIST_FOREACH(redirect_exit_list, exit_redirect_t *, p, tor_free(p));
smartlist_free(redirect_exit_list);
}
redirect_exit_list = lst;
}
/** If address is of the form "y.onion" with a well-formed handle y:
* Put a '\0' after y, lower-case it, and return ONION_HOSTNAME.
*
* If address is of the form "y.exit":
* Put a '\0' after y and return EXIT_HOSTNAME.
*
* Otherwise:
* Return NORMAL_HOSTNAME and change nothing.
*/
hostname_type_t
parse_extended_hostname(char *address) {
char *s;
char query[REND_SERVICE_ID_LEN+1];
s = strrchr(address,'.');
if (!s) return 0; /* no dot, thus normal */
if (!strcasecmp(s+1,"exit")) {
*s = 0; /* null-terminate it */
return EXIT_HOSTNAME; /* .exit */
}
if (strcasecmp(s+1,"onion"))
return NORMAL_HOSTNAME; /* neither .exit nor .onion, thus normal */
/* so it is .onion */
*s = 0; /* null-terminate it */
if (strlcpy(query, address, REND_SERVICE_ID_LEN+1) >= REND_SERVICE_ID_LEN+1)
goto failed;
tor_strlower(query);
if (rend_valid_service_id(query)) {
tor_strlower(address);
return ONION_HOSTNAME; /* success */
}
failed:
/* otherwise, return to previous state and return 0 */
*s = '.';
return NORMAL_HOSTNAME;
}