text: /* ssl/dtls1.h */
  /*
   * DTLS implementation written by Nagendra Modadugu
   * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
   */
  /* ====================================================================
   * Copyright (c) 1999-2005 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    openssl-core@OpenSSL.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com).
   *
   */
  
  #ifndef HEADER_DTLS1_H
  # define HEADER_DTLS1_H
  
  # include <openssl/buffer.h>
  # include <openssl/pqueue.h>
  # ifdef OPENSSL_SYS_VMS
  #  include <resource.h>
  #  include <sys/timeb.h>
  # endif
  # ifdef OPENSSL_SYS_WIN32
  /* Needed for struct timeval */
  #  include <winsock.h>
  # elif defined(OPENSSL_SYS_NETWARE) && !defined(_WINSOCK2API_)
  #  include <sys/timeval.h>
  # else
  #  if defined(OPENSSL_SYS_VXWORKS)
  #   include <sys/times.h>
  #  else
  #   include <sys/time.h>
  #  endif
  # endif
  
  #ifdef  __cplusplus
  extern "C" {
  #endif
  
  # define DTLS1_VERSION                   0xFEFF
  # define DTLS1_2_VERSION                 0xFEFD
  # define DTLS_MAX_VERSION                DTLS1_2_VERSION
  # define DTLS1_VERSION_MAJOR             0xFE
  
  # define DTLS1_BAD_VER                   0x0100
  
  /* Special value for method supporting multiple versions */
  # define DTLS_ANY_VERSION                0x1FFFF
  
  # if 0
  /* this alert description is not specified anywhere... */
  #  define DTLS1_AD_MISSING_HANDSHAKE_MESSAGE    110
  # endif
  
  /* lengths of messages */
  # define DTLS1_COOKIE_LENGTH                     256
  
  # define DTLS1_RT_HEADER_LENGTH                  13
  
  # define DTLS1_HM_HEADER_LENGTH                  12
  
  # define DTLS1_HM_BAD_FRAGMENT                   -2
  # define DTLS1_HM_FRAGMENT_RETRY                 -3
  
  # define DTLS1_CCS_HEADER_LENGTH                  1
  
  # ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
  #  define DTLS1_AL_HEADER_LENGTH                   7
  # else
  #  define DTLS1_AL_HEADER_LENGTH                   2
  # endif
  
  # ifndef OPENSSL_NO_SSL_INTERN
  
  #  ifndef OPENSSL_NO_SCTP
  #   define DTLS1_SCTP_AUTH_LABEL   "EXPORTER_DTLS_OVER_SCTP"
  #  endif
  
  /* Max MTU overhead we know about so far is 40 for IPv6 + 8 for UDP */
  #  define DTLS1_MAX_MTU_OVERHEAD                   48
  
  typedef struct dtls1_bitmap_st {
      unsigned long map;          /* track 32 packets on 32-bit systems and 64
                                   * - on 64-bit systems */
      unsigned char max_seq_num[8]; /* max record number seen so far, 64-bit
                                     * value in big-endian encoding */
  } DTLS1_BITMAP;
  
  struct dtls1_retransmit_state {
      EVP_CIPHER_CTX *enc_write_ctx; /* cryptographic state */
      EVP_MD_CTX *write_hash;     /* used for mac generation */
  #  ifndef OPENSSL_NO_COMP
      COMP_CTX *compress;         /* compression */
  #  else
      char *compress;
  #  endif
      SSL_SESSION *session;
      unsigned short epoch;
  };
  
  struct hm_header_st {
      unsigned char type;
      unsigned long msg_len;
      unsigned short seq;
      unsigned long frag_off;
      unsigned long frag_len;
      unsigned int is_ccs;
      struct dtls1_retransmit_state saved_retransmit_state;
  };
  
  struct ccs_header_st {
      unsigned char type;
      unsigned short seq;
  };
  
  struct dtls1_timeout_st {
      /* Number of read timeouts so far */
      unsigned int read_timeouts;
      /* Number of write timeouts so far */
      unsigned int write_timeouts;
      /* Number of alerts received so far */
      unsigned int num_alerts;
  };
  
  typedef struct record_pqueue_st {
      unsigned short epoch;
      pqueue q;
  } record_pqueue;
  
  typedef struct hm_fragment_st {
      struct hm_header_st msg_header;
      unsigned char *fragment;
      unsigned char *reassembly;
  } hm_fragment;
  
  typedef struct dtls1_state_st {
      unsigned int send_cookie;
      unsigned char cookie[DTLS1_COOKIE_LENGTH];
      unsigned char rcvd_cookie[DTLS1_COOKIE_LENGTH];
      unsigned int cookie_len;
      /*
       * The current data and handshake epoch.  This is initially
       * undefined, and starts at zero once the initial handshake is
       * completed
       */
      unsigned short r_epoch;
      unsigned short w_epoch;
      /* records being received in the current epoch */
      DTLS1_BITMAP bitmap;
      /* renegotiation starts a new set of sequence numbers */
      DTLS1_BITMAP next_bitmap;
      /* handshake message numbers */
      unsigned short handshake_write_seq;
      unsigned short next_handshake_write_seq;
      unsigned short handshake_read_seq;
      /* save last sequence number for retransmissions */
      unsigned char last_write_sequence[8];
      /* Received handshake records (processed and unprocessed) */
      record_pqueue unprocessed_rcds;
      record_pqueue processed_rcds;
      /* Buffered handshake messages */
      pqueue buffered_messages;
      /* Buffered (sent) handshake records */
      pqueue sent_messages;
      /*
       * Buffered application records. Only for records between CCS and
       * Finished to prevent either protocol violation or unnecessary message
       * loss.
       */
      record_pqueue buffered_app_data;
      /* Is set when listening for new connections with dtls1_listen() */
      unsigned int listen;
      unsigned int link_mtu;      /* max on-the-wire DTLS packet size */
      unsigned int mtu;           /* max DTLS packet size */
      struct hm_header_st w_msg_hdr;
      struct hm_header_st r_msg_hdr;
      struct dtls1_timeout_st timeout;
      /*
       * Indicates when the last handshake msg or heartbeat sent will timeout
       */
      struct timeval next_timeout;
      /* Timeout duration */
      unsigned short timeout_duration;
      /*
       * storage for Alert/Handshake protocol data received but not yet
       * processed by ssl3_read_bytes:
       */
      unsigned char alert_fragment[DTLS1_AL_HEADER_LENGTH];
      unsigned int alert_fragment_len;
      unsigned char handshake_fragment[DTLS1_HM_HEADER_LENGTH];
      unsigned int handshake_fragment_len;
      unsigned int retransmitting;
      /*
       * Set when the handshake is ready to process peer's ChangeCipherSpec message.
       * Cleared after the message has been processed.
       */
      unsigned int change_cipher_spec_ok;
  #  ifndef OPENSSL_NO_SCTP
      /* used when SSL_ST_XX_FLUSH is entered */
      int next_state;
      int shutdown_received;
  #  endif
  } DTLS1_STATE;
  
  typedef struct dtls1_record_data_st {
      unsigned char *packet;
      unsigned int packet_length;
      SSL3_BUFFER rbuf;
      SSL3_RECORD rrec;
  #  ifndef OPENSSL_NO_SCTP
      struct bio_dgram_sctp_rcvinfo recordinfo;
  #  endif
  } DTLS1_RECORD_DATA;
  
  # endif
  
  /* Timeout multipliers (timeout slice is defined in apps/timeouts.h */
  # define DTLS1_TMO_READ_COUNT                      2
  # define DTLS1_TMO_WRITE_COUNT                     2
  
  # define DTLS1_TMO_ALERT_COUNT                     12
  
  #ifdef  __cplusplus
  }
  #endif
  #endif
  