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 <timespec.h>
  31
  32 int _dtls_transmit(gnutls_session_t session);
  33 int _dtls_retransmit(gnutls_session_t session);
  34 int _dtls_record_check(struct record_parameters_st *rp, uint64 * _seq);
  35
  36 #define MAX_DTLS_TIMEOUT 60000
  37
  38 /* returns a-b in ms */
  39 inline static unsigned int timespec_sub_ms(struct timespec *a, struct timespec *b)
  40 {
  41   return (a->tv_sec * 1000 + a->tv_nsec / (1000 * 1000) -
  42           (b->tv_sec * 1000 + b->tv_nsec / (1000 * 1000)));
  43 }
  44
  45 #define RETURN_DTLS_EAGAIN_OR_TIMEOUT(session, r) { \
  46   struct timespec now; \
  47   unsigned int diff; \
  48   gettime(&now); \
  49    \
  50   diff = timespec_sub_ms(&now, &session->internals.dtls.handshake_start_time); \
  51   if (diff > session->internals.dtls.total_timeout_ms) \
  52     { \
  53       _gnutls_dtls_log("Session timeout: %u ms\n", diff); \
  54       return gnutls_assert_val(GNUTLS_E_TIMEDOUT); \
  55     } \
  56   else \
  57     { \
  58       int rr; \
  59       if (r != GNUTLS_E_INTERRUPTED) rr = GNUTLS_E_AGAIN; \
  60       else rr = r; \
  61       if (session->internals.dtls.blocking != 0) \
  62         millisleep(50); \
  63       return gnutls_assert_val(rr); \
  64     } \
  65   }
  66
  67
  68 int _dtls_wait_and_retransmit(gnutls_session_t session);
  69
  70 /* returns true or false depending on whether we need to
  71  * handle asynchronously handshake data.
  72  */
  73 inline static int _dtls_is_async(gnutls_session_t session)
  74 {
  75   if ((session->security_parameters.entity == GNUTLS_SERVER && session->internals.resumed == RESUME_FALSE) ||
  76          (session->security_parameters.entity == GNUTLS_CLIENT && session->internals.resumed == RESUME_TRUE))
  77     return 1;
  78   else
  79     return 0;
  80 }
  81
  82 inline static void _dtls_async_timer_init(gnutls_session_t session)
  83 {
  84   if (_dtls_is_async(session))
  85     {
  86       _gnutls_dtls_log ("DTLS[%p]: Initializing timer for handshake state.\n", session);
  87       session->internals.dtls.async_term = gnutls_time(0) + MAX_DTLS_TIMEOUT/1000;
  88     }
  89   else
  90     session->internals.dtls.async_term = 0;
  91 }
  92
  93 inline static void _dtls_async_timer_delete(gnutls_session_t session)
  94 {
  95   if (session->internals.dtls.async_term != 0)
  96     {
  97       _gnutls_dtls_log ("DTLS[%p]: Deinitializing handshake state.\n", session);
  98       _gnutls_handshake_io_buffer_clear (session);
  99       session->internals.dtls.async_term = 0; /* turn off "timer" */
 100     }
 101 }
 102
 103 /* Checks whether it is time to terminate the timer
 104  */
 105 inline static void _dtls_async_timer_check(gnutls_session_t session)
 106 {
 107   if (!IS_DTLS(session))
 108     return;
 109
 110   if (session->internals.dtls.async_term != 0)
 111     {
 112       time_t now = time(0);
 113
 114       /* check if we need to expire the queued handshake data */
 115       if (now > session->internals.dtls.async_term)
 116         {
 117           _dtls_async_timer_delete(session);
 118         }
 119     }
 120 }
 121
 122 /* Returns non-zero if the async timer is active */
 123 inline static int _dtls_async_timer_active(gnutls_session_t session)
 124 {
 125   if (!IS_DTLS(session))
 126     return 0;
 127
 128   return session->internals.dtls.async_term;
 129 }
 130
 131 #endif