lib/gnutls_dtls.h

   1 /*
   2  * Copyright (C) 2009-2012 Free Software Foundation, Inc.
   3  *
   4  * Author: Jonathan Bastien-Filiatrault
   5  *
   6  * This file is part of GNUTLS.
   7  *
   8  * The GNUTLS library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 2.1 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this program.  If not, see <http://www.gnu.org/licenses/>
  20  *
  21  */
  22
  23 #ifndef DTLS_H
  24 #define DTLS_H
  25
  26 #include <config.h>
  27 #include <gnutls_int.h>
  28 #include <gnutls_buffers.h>
  29 #include <gnutls_mbuffers.h>
  30 #include <gnutls_constate.h>
  31
  32 int _dtls_transmit(gnutls_session_t session);
  33 int _dtls_record_check(struct record_parameters_st *rp, uint64 * _seq);
  34 void _dtls_reset_hsk_state(gnutls_session_t session);
  35
  36 #define MAX_DTLS_TIMEOUT 60000
  37
  38
  39 #define RETURN_DTLS_EAGAIN_OR_TIMEOUT(session, r) { \
  40   struct timespec now; \
  41   unsigned int diff; \
  42   gettime(&now); \
  43    \
  44   diff = timespec_sub_ms(&now, &session->internals.dtls.handshake_start_time); \
  45   if (diff > session->internals.dtls.total_timeout_ms) \
  46     { \
  47       _gnutls_dtls_log("Session timeout: %u ms\n", diff); \
  48       return gnutls_assert_val(GNUTLS_E_TIMEDOUT); \
  49     } \
  50   else \
  51     { \
  52       int rr; \
  53       if (r != GNUTLS_E_INTERRUPTED) rr = GNUTLS_E_AGAIN; \
  54       else rr = r; \
  55       if (session->internals.dtls.blocking != 0) \
  56         millisleep(50); \
  57       return gnutls_assert_val(rr); \
  58     } \
  59   }
  60
  61
  62 int _dtls_wait_and_retransmit(gnutls_session_t session);
  63
  64 /* returns true or false depending on whether we need to
  65  * handle asynchronously handshake data.
  66  */
  67 inline static int _dtls_is_async(gnutls_session_t session)
  68 {
  69         if ((session->security_parameters.entity == GNUTLS_SERVER
  70              && session->internals.resumed == RESUME_FALSE)
  71             || (session->security_parameters.entity == GNUTLS_CLIENT
  72                 && session->internals.resumed == RESUME_TRUE))
  73                 return 1;
  74         else
  75                 return 0;
  76 }
  77
  78 inline static void _dtls_async_timer_init(gnutls_session_t session)
  79 {
  80         if (_dtls_is_async(session)) {
  81                 _gnutls_dtls_log
  82                     ("DTLS[%p]: Initializing timer for handshake state.\n",
  83                      session);
  84                 session->internals.dtls.async_term =
  85                     gnutls_time(0) + MAX_DTLS_TIMEOUT / 1000;
  86         } else {
  87                 _dtls_reset_hsk_state(session);
  88                 _gnutls_handshake_io_buffer_clear(session);
  89                 _gnutls_epoch_gc(session);
  90                 session->internals.dtls.async_term = 0;
  91         }
  92 }
  93
  94 void _dtls_async_timer_delete(gnutls_session_t session);
  95
  96 /* Checks whether it is time to terminate the timer
  97  */
  98 inline static void _dtls_async_timer_check(gnutls_session_t session)
  99 {
 100         if (!IS_DTLS(session))
 101                 return;
 102
 103         if (session->internals.dtls.async_term != 0) {
 104                 time_t now = time(0);
 105
 106                 /* check if we need to expire the queued handshake data */
 107                 if (now > session->internals.dtls.async_term) {
 108                         _dtls_async_timer_delete(session);
 109                 }
 110         }
 111 }
 112
 113 /* Returns non-zero if the async timer is active */
 114 inline static int _dtls_async_timer_active(gnutls_session_t session)
 115 {
 116         if (!IS_DTLS(session))
 117                 return 0;
 118
 119         return session->internals.dtls.async_term;
 120 }
 121
 122 /* This function is to be called from record layer once
 123  * a handshake replay is detected. It will make sure
 124  * it transmits only once per few seconds. Otherwise
 125  * it is the same as _dtls_transmit().
 126  */
 127 inline static int _dtls_retransmit(gnutls_session_t session)
 128 {
 129         return _dtls_transmit(session);
 130 }
 131
 132 #endif