Update libsrtp to version 2.0

crypto/math/stat.c

+/*
+ * stats.c
+ *
+ * statistical tests 
+ * 
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+
+/*
+ *      
+ * Copyright (c) 2001-2006, Cisco Systems, Inc.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ *   Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ * 
+ *   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.
+ * 
+ *   Neither the name of the Cisco Systems, Inc. nor the names of its
+ *   contributors may be used to endorse or promote products derived
+ *   from this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS 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
+ * COPYRIGHT HOLDERS OR 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.
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+    #include <config.h>
+#endif
+
+#include "stat.h"
+
+srtp_debug_module_t mod_stat = {
+  0,                 /* debugging is off by default */
+  (char *)"stat test"        /* printable module name       */
+};
+
+/*
+ * each test assumes that 20,000 bits (2500 octets) of data is
+ * provided as input
+ */
+
+#define STAT_TEST_DATA_LEN 2500
+
+srtp_err_status_t
+stat_test_monobit(uint8_t *data) {
+  uint8_t *data_end = data + STAT_TEST_DATA_LEN;
+  uint16_t ones_count;
+
+  ones_count = 0;
+  while (data < data_end) {
+    ones_count += octet_get_weight(*data);
+    data++;
+  }
+
+  debug_print(mod_stat, "bit count: %d", ones_count);
+  
+  if ((ones_count < 9725) || (ones_count > 10275))
+    return srtp_err_status_algo_fail;
+
+  return srtp_err_status_ok;
+}
+
+srtp_err_status_t
+stat_test_poker(uint8_t *data) {
+  int i;
+  uint8_t *data_end = data + STAT_TEST_DATA_LEN;
+  double poker;
+  uint16_t f[16] = {
+    0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0
+  };
+  
+  while (data < data_end) {
+    f[*data & 0x0f]++;    /* increment freq. count for low nibble  */
+    f[(*data) >> 4]++;    /* increment freq. count for high nibble */
+    data++;
+  }
+
+  poker = 0.0;
+  for (i=0; i < 16; i++) 
+    poker += (double) f[i] * f[i];
+
+  poker *= (16.0 / 5000.0);
+  poker -= 5000.0;
+
+  debug_print(mod_stat, "poker test: %f\n", poker);
+    
+  if ((poker < 2.16) || (poker > 46.17))
+    return srtp_err_status_algo_fail;
+  
+  return srtp_err_status_ok;
+}
+
+
+/*
+ * runs[i] holds the number of runs of size (i-1)
+ */
+
+srtp_err_status_t
+stat_test_runs(uint8_t *data) {
+  uint8_t *data_end = data + STAT_TEST_DATA_LEN;
+  uint16_t runs[6] = { 0, 0, 0, 0, 0, 0 }; 
+  uint16_t gaps[6] = { 0, 0, 0, 0, 0, 0 };
+  uint16_t lo_value[6] = { 2315, 1114, 527, 240, 103, 103 };
+  uint16_t hi_value[6] = { 2685, 1386, 723, 384, 209, 209 };
+  int state = 0;
+  uint16_t mask;
+  int i;
+  
+  /*
+   * the state variable holds the number of bits in the
+   * current run (or gap, if negative)
+   */
+  
+  while (data < data_end) {
+
+    /* loop over the bits of this byte */
+    for (mask = 1; mask < 256; mask <<= 1) {
+      if (*data & mask) {
+
+        /* next bit is a one  */
+        if (state > 0) {
+
+          /* prefix is a run, so increment the run-count  */
+          state++;                          
+
+          /* check for long runs */ 
+          if (state > 25) {
+                debug_print(mod_stat, ">25 runs: %d", state);
+                return srtp_err_status_algo_fail;
+          }
+
+        } else if (state < 0) {
+
+          /* prefix is a gap  */
+          if (state < -25) {
+                debug_print(mod_stat, ">25 gaps: %d", state);
+            return srtp_err_status_algo_fail;    /* long-runs test failed   */
+          }
+          if (state < -6) {
+            state = -6;                     /* group together gaps > 5 */
+          }
+          gaps[-1-state]++;                 /* increment gap count      */
+          state = 1;                        /* set state at one set bit */
+        } else {
+
+          /* state is zero; this happens only at initialization        */
+          state = 1;            
+        }
+      } else {
+
+        /* next bit is a zero  */
+        if (state > 0) {
+
+          /* prefix is a run */
+          if (state > 25) {
+                debug_print(mod_stat, ">25 runs (2): %d", state);
+            return srtp_err_status_algo_fail;    /* long-runs test failed   */
+          }
+          if (state > 6) {
+            state = 6;                      /* group together runs > 5 */
+          }
+          runs[state-1]++;                  /* increment run count       */
+          state = -1;                       /* set state at one zero bit */
+        } else if (state < 0) {
+
+          /* prefix is a gap, so increment gap-count (decrement state) */
+          state--;
+
+          /* check for long gaps */ 
+          if (state < -25) {
+                debug_print(mod_stat, ">25 gaps (2): %d", state);
+            return srtp_err_status_algo_fail;
+          }
+
+        } else {
+
+          /* state is zero; this happens only at initialization        */
+          state = -1;
+        }
+      }
+    }
+
+    /* move along to next octet */
+    data++;
+  }
+
+  if (mod_stat.on) {
+    debug_print(mod_stat, "runs test", NULL);
+    for (i=0; i < 6; i++)
+      debug_print(mod_stat, "  runs[]: %d", runs[i]);
+    for (i=0; i < 6; i++)
+      debug_print(mod_stat, "  gaps[]: %d", gaps[i]);
+  }
+
+  /* check run and gap counts against the fixed limits */
+  for (i=0; i < 6; i++) 
+    if (   (runs[i] < lo_value[i] ) || (runs[i] > hi_value[i])
+        || (gaps[i] < lo_value[i] ) || (gaps[i] > hi_value[i]))
+      return srtp_err_status_algo_fail;
+
+  
+  return srtp_err_status_ok;
+}
+
+