srtp_driver.c

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	   stream->rtcp_cipher->type->description,
	   stream->rtcp_auth->type->description,
	   serv_descr[stream->rtcp_services]);
  }

  /* loop over streams in session, printing the policy of each */
  stream = srtp->stream_list;
  while (stream != NULL) {
    if (stream->rtp_services > sec_serv_conf_and_auth)
      return err_status_bad_param;
    
    printf("# SSRC:          0x%08x\r\n"
	   "# rtp cipher:    %s\r\n"
	   "# rtp auth:      %s\r\n"
	   "# rtp services:  %s\r\n" 
           "# rtcp cipher:   %s\r\n"
	   "# rtcp auth:     %s\r\n"
	   "# rtcp services: %s\r\n",
	   stream->ssrc,
	   stream->rtp_cipher->type->description,
	   stream->rtp_auth->type->description,
	   serv_descr[stream->rtp_services],
	   stream->rtcp_cipher->type->description,
	   stream->rtcp_auth->type->description,
	   serv_descr[stream->rtcp_services]);

    /* advance to next stream in the list */
    stream = stream->next;
  } 
  return err_status_ok;
}

err_status_t
srtp_print_policy(const srtp_policy_t *policy) {
  err_status_t status;
  srtp_t session;

  status = srtp_create(&session, policy);
  if (status)
    return status;
  status = srtp_session_print_policy(session);
  if (status)
    return status;
  status = srtp_dealloc(session);
  if (status)
    return status;
  return err_status_ok;
}

/* 
 * srtp_print_packet(...) is for debugging only 
 * it prints an RTP packet to the stdout
 *
 * note that this function is *not* threadsafe
 */

#include <stdio.h>

#define MTU 2048

char packet_string[MTU];

char *
srtp_packet_to_string(srtp_hdr_t *hdr, int pkt_octet_len) {
  int octets_in_rtp_header = 12;
  uint8_t *data = ((uint8_t *)hdr)+octets_in_rtp_header;
  int hex_len = pkt_octet_len-octets_in_rtp_header;

  /* sanity checking */
  if ((hdr == NULL) || (pkt_octet_len > MTU))
    return NULL;

  /* write packet into string */
  sprintf(packet_string, 
	  "(s)rtp packet: {\n"
	  "   version:\t%d\n" 
	  "   p:\t\t%d\n"     
	  "   x:\t\t%d\n"     
	  "   cc:\t\t%d\n"    
	  "   m:\t\t%d\n"     
	  "   pt:\t\t%x\n"    
	  "   seq:\t\t%x\n"   
	  "   ts:\t\t%x\n"    
	  "   ssrc:\t%x\n"    
	  "   data:\t%s\n"    
	  "} (%d octets in total)\n", 
	  hdr->version,  
	  hdr->p,	       
	  hdr->x,	       
	  hdr->cc,       
	  hdr->m,	       
	  hdr->pt,       
	  hdr->seq,      
	  hdr->ts,       
	  hdr->ssrc,      
  	  octet_string_hex_string(data, hex_len),
	  pkt_octet_len);

  return packet_string;
}

/*
 * mips_estimate() is a simple function to estimate the number of
 * instructions per second that the host can perform.  note that this
 * function can be grossly wrong; you may want to have a manual sanity
 * check of its output!
 *
 * the 'ignore' pointer is there to convince the compiler to not just
 * optimize away the function
 */

double
mips_estimate(int num_trials, int *ignore) {
  clock_t t;
  int i, sum;

  sum = 0;
  t = clock();
  for (i=0; i<num_trials; i++)
    sum += i;
  t = clock() - t;

/*   printf("%d\n", sum); */
  *ignore = sum;

  return (double) num_trials * CLOCKS_PER_SEC / t;
}


/*
 * srtp_validate() verifies the correctness of libsrtp by comparing
 * some computed packets against some pre-computed reference values.
 * These packets were made with the default SRTP policy.
 */


err_status_t
srtp_validate() {
  unsigned char test_key[30] = {
    0xe1, 0xf9, 0x7a, 0x0d, 0x3e, 0x01, 0x8b, 0xe0,
    0xd6, 0x4f, 0xa3, 0x2c, 0x06, 0xde, 0x41, 0x39,
    0x0e, 0xc6, 0x75, 0xad, 0x49, 0x8a, 0xfe, 0xeb,
    0xb6, 0x96, 0x0b, 0x3a, 0xab, 0xe6
  };
  uint8_t srtp_plaintext_ref[28] = {
    0x80, 0x0f, 0x12, 0x34, 0xde, 0xca, 0xfb, 0xad, 
    0xca, 0xfe, 0xba, 0xbe, 0xab, 0xab, 0xab, 0xab,
    0xab, 0xab, 0xab, 0xab, 0xab, 0xab, 0xab, 0xab, 
    0xab, 0xab, 0xab, 0xab
  };
  uint8_t srtp_plaintext[38] = {
    0x80, 0x0f, 0x12, 0x34, 0xde, 0xca, 0xfb, 0xad, 
    0xca, 0xfe, 0xba, 0xbe, 0xab, 0xab, 0xab, 0xab,
    0xab, 0xab, 0xab, 0xab, 0xab, 0xab, 0xab, 0xab, 
    0xab, 0xab, 0xab, 0xab, 0x00, 0x00, 0x00, 0x00, 
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00
  };
  uint8_t srtp_ciphertext[38] = {
    0x80, 0x0f, 0x12, 0x34, 0xde, 0xca, 0xfb, 0xad, 
    0xca, 0xfe, 0xba, 0xbe, 0x4e, 0x55, 0xdc, 0x4c,
    0xe7, 0x99, 0x78, 0xd8, 0x8c, 0xa4, 0xd2, 0x15, 
    0x94, 0x9d, 0x24, 0x02, 0xb7, 0x8d, 0x6a, 0xcc,
    0x99, 0xea, 0x17, 0x9b, 0x8d, 0xbb
  };
  srtp_t srtp_snd, srtp_recv;
  err_status_t status;
  int len;
  srtp_policy_t policy;
  
  /*
   * create a session with a single stream using the default srtp
   * policy and with the SSRC value 0xcafebabe
   */
  crypto_policy_set_rtp_default(&policy.rtp);
  crypto_policy_set_rtcp_default(&policy.rtcp);
  policy.ssrc.type  = ssrc_specific;
  policy.ssrc.value = 0xcafebabe;
  policy.key  = test_key;
  policy.next = NULL;

  status = srtp_create(&srtp_snd, &policy);
  if (status)
    return status;
 
  /* 
   * protect plaintext, then compare with ciphertext 
   */
  len = 28;
  status = srtp_protect(srtp_snd, srtp_plaintext, &len);
  if (status || (len != 38))
    return err_status_fail;

  debug_print(mod_driver, "ciphertext:\n  %s", 	      
	      octet_string_hex_string(srtp_plaintext, len));
  debug_print(mod_driver, "ciphertext reference:\n  %s", 	      
	      octet_string_hex_string(srtp_ciphertext, len));

  if (octet_string_is_eq(srtp_plaintext, srtp_ciphertext, len))
    return err_status_fail;
  
  /*
   * create a receiver session context comparable to the one created
   * above - we need to do this so that the replay checking doesn't
   * complain
   */
  status = srtp_create(&srtp_recv, &policy);
  if (status)
    return status;

  /*
   * unprotect ciphertext, then compare with plaintext 
   */
  status = srtp_unprotect(srtp_recv, srtp_ciphertext, &len);
  if (status || (len != 28))
    return status;
  
  if (octet_string_is_eq(srtp_ciphertext, srtp_plaintext_ref, len))
    return err_status_fail;

  return err_status_ok;
}


err_status_t
srtp_create_big_policy(srtp_policy_t **list) {
  extern const srtp_policy_t *policy_array[];
  srtp_policy_t *p, *tmp;
  int i = 0;
  uint32_t ssrc = 0;

  /* sanity checking */
  if ((list == NULL) || (policy_array[0] == NULL))
    return err_status_bad_param;

  /* 
   * loop over policy list, mallocing a new list and copying values
   * into it (and incrementing the SSRC value as we go along)
   */
  tmp = NULL;
  while (policy_array[i] != NULL) {
    p  = (srtp_policy_t*) malloc(sizeof(srtp_policy_t));
    if (p == NULL)
      return err_status_bad_param;
    memcpy(p, policy_array[i], sizeof(srtp_policy_t));
    p->ssrc.type = ssrc_specific;
    p->ssrc.value = ssrc++;
    p->next = tmp;
    tmp = p;
    i++;
  }
  *list = p;
 
  return err_status_ok;
}

err_status_t
srtp_test_remove_stream() { 
  err_status_t status;
  srtp_policy_t *policy_list;
  srtp_t session;
  srtp_stream_t stream;
  /* 
   * srtp_get_stream() is a libSRTP internal function that we declare
   * here so that we can use it to verify the correct operation of the
   * library
   */ 
  extern srtp_stream_t srtp_get_stream(srtp_t srtp, uint32_t ssrc);
  

  status = srtp_create_big_policy(&policy_list);
  if (status)
    return status;

  status = srtp_create(&session, policy_list);
  if (status)
    return status;

  /*
   * check for false positives by trying to remove a stream that's not
   * in the session
   */
  status = srtp_remove_stream(session, htonl(0xaaaaaaaa));
  if (status != err_status_no_ctx)
    return err_status_fail;
  
  /* 
   * check for false negatives by removing stream 0x1, then
   * searching for streams 0x0 and 0x2
   */
  status = srtp_remove_stream(session, htonl(0x1));
  if (status != err_status_ok)
    return err_status_fail;
  stream = srtp_get_stream(session, htonl(0x0));
  if (stream == NULL)
    return err_status_fail;
  stream = srtp_get_stream(session, htonl(0x2));
  if (stream == NULL)
    return err_status_fail;  

  return err_status_ok;  
}

/*
 * srtp policy definitions - these definitions are used above
 */

unsigned char test_key[30] = {
    0xe1, 0xf9, 0x7a, 0x0d, 0x3e, 0x01, 0x8b, 0xe0,
    0xd6, 0x4f, 0xa3, 0x2c, 0x06, 0xde, 0x41, 0x39,
    0x0e, 0xc6, 0x75, 0xad, 0x49, 0x8a, 0xfe, 0xeb,
    0xb6, 0x96, 0x0b, 0x3a, 0xab, 0xe6
};


const srtp_policy_t default_policy = {
  { ssrc_any_outbound, 0 },  /* SSRC                           */
  {                      /* SRTP policy                    */                  
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    HMAC_SHA1,              /* authentication func type    */
    16,                     /* auth key length in octets   */
    10,                     /* auth tag length in octets   */
    sec_serv_conf_and_auth  /* security services flag      */
  },
  {                      /* SRTCP policy                   */
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    HMAC_SHA1,              /* authentication func type    */
    16,                     /* auth key length in octets   */
    10,                     /* auth tag length in octets   */
    sec_serv_conf_and_auth  /* security services flag      */
  },
  test_key,
  NULL
};

const srtp_policy_t aes_tmmh_policy = {
  { ssrc_any_outbound, 0 },     /* SSRC                        */
  { 
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    UST_TMMHv2,             /* authentication func type    */
    94,                     /* auth key length in octets   */
    4,                      /* auth tag length in octets   */
    sec_serv_conf_and_auth  /* security services flag      */
  },
  { 
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    UST_TMMHv2,             /* authentication func type    */
    94,                     /* auth key length in octets   */
    4,                      /* auth tag length in octets   */
    sec_serv_conf_and_auth  /* security services flag      */
  },
  test_key,
  NULL
};

const srtp_policy_t tmmh_only_policy = {
  { ssrc_any_outbound, 0 },     /* SSRC                        */
  {
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    UST_TMMHv2,             /* authentication func type    */
    94,                     /* auth key length in octets   */
    4,                      /* auth tag length in octets   */
    sec_serv_auth           /* security services flag      */
  },
  {
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    UST_TMMHv2,             /* authentication func type    */
    94,                     /* auth key length in octets   */
    4,                      /* auth tag length in octets   */
    sec_serv_auth           /* security services flag      */
  },
  test_key,
  NULL
};

const srtp_policy_t aes_only_policy = {
  { ssrc_any_outbound, 0 },     /* SSRC                        */ 
  {
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    NULL_AUTH,              /* authentication func type    */
    0,                      /* auth key length in octets   */
    0,                      /* auth tag length in octets   */
    sec_serv_conf           /* security services flag      */
  },
  {
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    NULL_AUTH,              /* authentication func type    */
    0,                      /* auth key length in octets   */
    0,                      /* auth tag length in octets   */
    sec_serv_conf           /* security services flag      */
  },
  test_key,
  NULL
};

const srtp_policy_t hmac_only_policy = {
  { ssrc_any_outbound, 0 },     /* SSRC                        */
  {
    NULL_CIPHER,            /* cipher type                 */
    0,                      /* cipher key length in octets */
    HMAC_SHA1,              /* authentication func type    */
    20,                     /* auth key length in octets   */
    4,                      /* auth tag length in octets   */
    sec_serv_auth           /* security services flag      */
  },  
  {
    NULL_CIPHER,            /* cipher type                 */
    0,                      /* cipher key length in octets */
    HMAC_SHA1,              /* authentication func type    */
    20,                     /* auth key length in octets   */
    4,                      /* auth tag length in octets   */
    sec_serv_auth           /* security services flag      */
  },
  test_key,
  NULL
};

const srtp_policy_t null_policy = {
  { ssrc_any_outbound, 0 },     /* SSRC                        */ 
  {
    NULL_CIPHER,            /* cipher type                 */
    0,                      /* cipher key length in octets */
    NULL_AUTH,              /* authentication func type    */
    0,                      /* auth key length in octets   */
    0,                      /* auth tag length in octets   */
    sec_serv_none           /* security services flag      */  
  },
  {
    NULL_CIPHER,            /* cipher type                 */
    0,                      /* cipher key length in octets */
    NULL_AUTH,              /* authentication func type    */
    0,                      /* auth key length in octets   */
    0,                      /* auth tag length in octets   */
    sec_serv_none           /* security services flag      */  
  },
  test_key,
  NULL
};


/*
 * an array of pointers to the policies listed above
 *
 * This array is used to test various aspects of libSRTP for
 * different cryptographic policies.  The order of the elements
 * matters - the timing test generates output that can be used
 * in a plot (see the gnuplot script file 'timing').  If you 
 * add to this list, you should do it at the end.
 */

#define USE_TMMH 0

const srtp_policy_t *
policy_array[] = {
  &hmac_only_policy,
#if USE_TMMH
  &tmmh_only_policy,
#endif
  &aes_only_policy,
#if USE_TMMH
  &aes_tmmh_policy,
#endif
  &default_policy,
  &null_policy,
  NULL
};

const srtp_policy_t wildcard_policy = {
  { ssrc_any_outbound, 0 }, /* SSRC                        */
  {                      /* SRTP policy                    */                  
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    HMAC_SHA1,              /* authentication func type    */
    16,                     /* auth key length in octets   */
    10,                     /* auth tag length in octets   */
    sec_serv_conf_and_auth  /* security services flag      */
  },
  {                      /* SRTCP policy                   */
    AES_128_ICM,            /* cipher type                 */
    30,                     /* cipher key length in octets */
    HMAC_SHA1,              /* authentication func type    */
    16,                     /* auth key length in octets   */
    10,                     /* auth tag length in octets   */
    sec_serv_conf_and_auth  /* security services flag      */
  },
  test_key,
  NULL
};