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 3 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 #include <timespec.h>
  32
  33 int _dtls_transmit(gnutls_session_t session);
  34 int _dtls_record_check(struct record_parameters_st *rp, uint64 * _seq);
  35 void _dtls_reset_hsk_state(gnutls_session_t session);
  36
  37 #define MAX_DTLS_TIMEOUT 60000
  38
  39 unsigned int _dtls_timespec_sub_ms (struct timespec *a, struct timespec *b);
  40
  41 #define RETURN_DTLS_EAGAIN_OR_TIMEOUT(session, r) { \
  42   struct timespec now; \
  43   unsigned int diff; \
  44   gettime(&now); \
  45    \
  46   diff = _dtls_timespec_sub_ms(&now, &session->internals.dtls.handshake_start_time); \
  47   if (diff > session->internals.dtls.total_timeout_ms) \
  48     { \
  49       _gnutls_dtls_log("Session timeout: %u ms\n", diff); \
  50       return gnutls_assert_val(GNUTLS_E_TIMEDOUT); \
  51     } \
  52   else \
  53     { \
  54       int rr; \
  55       if (r != GNUTLS_E_INTERRUPTED) rr = GNUTLS_E_AGAIN; \
  56       else rr = r; \
  57       if (session->internals.dtls.blocking != 0) \
  58         millisleep(50); \
  59       return gnutls_assert_val(rr); \
  60     } \
  61   }
  62
  63
  64 int _dtls_wait_and_retransmit(gnutls_session_t session);
  65
  66 /* returns true or false depending on whether we need to
  67  * handle asynchronously handshake data.
  68  */
  69 inline static int _dtls_is_async(gnutls_session_t session)
  70 {
  71   if ((session->security_parameters.entity == GNUTLS_SERVER && session->internals.resumed == RESUME_FALSE) ||
  72          (session->security_parameters.entity == GNUTLS_CLIENT && 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     {
  82       _gnutls_dtls_log ("DTLS[%p]: Initializing timer for handshake state.\n", session);
  83       session->internals.dtls.async_term = gnutls_time(0) + MAX_DTLS_TIMEOUT/1000;
  84     }
  85   else
  86     {
  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     {
 105       time_t now = time(0);
 106
 107       /* check if we need to expire the queued handshake data */
 108       if (now > session->internals.dtls.async_term)
 109         {
 110           _dtls_async_timer_delete(session);
 111         }
 112     }
 113 }
 114
 115 /* Returns non-zero if the async timer is active */
 116 inline static int _dtls_async_timer_active(gnutls_session_t session)
 117 {
 118   if (!IS_DTLS(session))
 119     return 0;
 120
 121   return session->internals.dtls.async_term;
 122 }
 123
 124 /* This function is to be called from record layer once
 125  * a handshake replay is detected. It will make sure
 126  * it transmits only once per few seconds. Otherwise
 127  * it is the same as _dtls_transmit().
 128  */
 129 inline static int _dtls_retransmit(gnutls_session_t session)
 130 {
 131   return _dtls_transmit(session);
 132 }
 133
 134 #endif