Commit ad93c0a2 authored by Roger Dingledine's avatar Roger Dingledine
Browse files

make sure there's no conflict when generating stream_ids 


svn:r955
parent a5e6ec24

src/or/connection_edge.c

+28 −2
Original line number Diff line number Diff line
@@ -665,6 +665,29 @@ static int connection_ap_handshake_attach_circuit(connection_t *conn) { 
  return 1;

}



/* Iterate over the two bytes of stream_id until we get one that is not

 * already in use. 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;

}



/* deliver the destaddr:destport in a relay cell */

static void connection_ap_handshake_send_begin(connection_t *ap_conn, circuit_t *circ)

{
@@ -677,8 +700,11 @@ static void connection_ap_handshake_send_begin(connection_t *ap_conn, circuit_t 
  assert(ap_conn->state == AP_CONN_STATE_CIRCUIT_WAIT);

  assert(ap_conn->socks_request);



  crypto_pseudo_rand(sizeof(ap_conn->stream_id), (unsigned char*) &ap_conn->stream_id);

  /* XXX check for collisions */

  ap_conn->stream_id = get_unique_stream_id_by_circ(circ);

  if (ap_conn->stream_id==0) {

    ap_conn->marked_for_close = 1;

    return;

  }



  in.s_addr = htonl(client_dns_lookup_entry(ap_conn->socks_request->address));

  string_addr = in.s_addr ? inet_ntoa(in) : NULL;

src/or/or.h

+1 −0
Original line number Diff line number Diff line
@@ -445,6 +445,7 @@ struct circuit_t { 
  connection_t *n_conn; /* for the OR conn, if there is one */

  connection_t *p_streams;

  connection_t *n_streams;

  uint16_t next_stream_id;

  int package_window;

  int deliver_window;