Upgrade libsrtp from 2.0.0 to 2.3.0, with source code. 4.0.79

trunk/3rdparty/libsrtp-2-fit/crypto/math/datatypes.c

@@ -0,0 +1,490 @@
+/*
+ * datatypes.c
+ *
+ * data types for finite fields and functions for input, output, and
+ * manipulation
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+/*
+ *
+ * Copyright (c) 2001-2017 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
+
+#ifdef OPENSSL
+#include <openssl/crypto.h>
+#endif
+
+#include "datatypes.h"
+
+static const int8_t octet_weight[256] = {
+    0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3, 2, 3, 3, 4,
+    2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4,
+    2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,
+    4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5,
+    3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+    2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6,
+    4, 5, 5, 6, 5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+    4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
+};
+
+int octet_get_weight(uint8_t octet)
+{
+    return (int)octet_weight[octet];
+}
+
+/*
+ * bit_string is a buffer that is used to hold output strings, e.g.
+ * for printing.
+ */
+
+/* the value MAX_PRINT_STRING_LEN is defined in datatypes.h */
+
+char bit_string[MAX_PRINT_STRING_LEN];
+
+uint8_t srtp_nibble_to_hex_char(uint8_t nibble)
+{
+    char buf[16] = { '0', '1', '2', '3', '4', '5', '6', '7',
+                     '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
+    return buf[nibble & 0xF];
+}
+
+char *srtp_octet_string_hex_string(const void *s, int length)
+{
+    const uint8_t *str = (const uint8_t *)s;
+    int i;
+
+    /* double length, since one octet takes two hex characters */
+    length *= 2;
+
+    /* truncate string if it would be too long */
+    if (length > MAX_PRINT_STRING_LEN)
+        length = MAX_PRINT_STRING_LEN - 2;
+
+    for (i = 0; i < length; i += 2) {
+        bit_string[i] = srtp_nibble_to_hex_char(*str >> 4);
+        bit_string[i + 1] = srtp_nibble_to_hex_char(*str++ & 0xF);
+    }
+    bit_string[i] = 0; /* null terminate string */
+    return bit_string;
+}
+
+char *v128_hex_string(v128_t *x)
+{
+    int i, j;
+
+    for (i = j = 0; i < 16; i++) {
+        bit_string[j++] = srtp_nibble_to_hex_char(x->v8[i] >> 4);
+        bit_string[j++] = srtp_nibble_to_hex_char(x->v8[i] & 0xF);
+    }
+
+    bit_string[j] = 0; /* null terminate string */
+    return bit_string;
+}
+
+char *v128_bit_string(v128_t *x)
+{
+    int j, i;
+    uint32_t mask;
+
+    for (j = i = 0; j < 4; j++) {
+        for (mask = 0x80000000; mask > 0; mask >>= 1) {
+            if (x->v32[j] & mask)
+                bit_string[i] = '1';
+            else
+                bit_string[i] = '0';
+            ++i;
+        }
+    }
+    bit_string[128] = 0; /* null terminate string */
+
+    return bit_string;
+}
+
+void v128_copy_octet_string(v128_t *x, const uint8_t s[16])
+{
+#ifdef ALIGNMENT_32BIT_REQUIRED
+    if ((((uint32_t)&s[0]) & 0x3) != 0)
+#endif
+    {
+        x->v8[0] = s[0];
+        x->v8[1] = s[1];
+        x->v8[2] = s[2];
+        x->v8[3] = s[3];
+        x->v8[4] = s[4];
+        x->v8[5] = s[5];
+        x->v8[6] = s[6];
+        x->v8[7] = s[7];
+        x->v8[8] = s[8];
+        x->v8[9] = s[9];
+        x->v8[10] = s[10];
+        x->v8[11] = s[11];
+        x->v8[12] = s[12];
+        x->v8[13] = s[13];
+        x->v8[14] = s[14];
+        x->v8[15] = s[15];
+    }
+#ifdef ALIGNMENT_32BIT_REQUIRED
+    else {
+        v128_t *v = (v128_t *)&s[0];
+
+        v128_copy(x, v);
+    }
+#endif
+}
+
+#ifndef DATATYPES_USE_MACROS /* little functions are not macros */
+
+void v128_set_to_zero(v128_t *x)
+{
+    _v128_set_to_zero(x);
+}
+
+void v128_copy(v128_t *x, const v128_t *y)
+{
+    _v128_copy(x, y);
+}
+
+void v128_xor(v128_t *z, v128_t *x, v128_t *y)
+{
+    _v128_xor(z, x, y);
+}
+
+void v128_and(v128_t *z, v128_t *x, v128_t *y)
+{
+    _v128_and(z, x, y);
+}
+
+void v128_or(v128_t *z, v128_t *x, v128_t *y)
+{
+    _v128_or(z, x, y);
+}
+
+void v128_complement(v128_t *x)
+{
+    _v128_complement(x);
+}
+
+int v128_is_eq(const v128_t *x, const v128_t *y)
+{
+    return _v128_is_eq(x, y);
+}
+
+int v128_xor_eq(v128_t *x, const v128_t *y)
+{
+    return _v128_xor_eq(x, y);
+}
+
+int v128_get_bit(const v128_t *x, int i)
+{
+    return _v128_get_bit(x, i);
+}
+
+void v128_set_bit(v128_t *x, int i)
+{
+    _v128_set_bit(x, i);
+}
+
+void v128_clear_bit(v128_t *x, int i)
+{
+    _v128_clear_bit(x, i);
+}
+
+void v128_set_bit_to(v128_t *x, int i, int y)
+{
+    _v128_set_bit_to(x, i, y);
+}
+
+#endif /* DATATYPES_USE_MACROS */
+
+void v128_right_shift(v128_t *x, int shift)
+{
+    const int base_index = shift >> 5;
+    const int bit_index = shift & 31;
+    int i, from;
+    uint32_t b;
+
+    if (shift > 127) {
+        v128_set_to_zero(x);
+        return;
+    }
+
+    if (bit_index == 0) {
+        /* copy each word from left size to right side */
+        x->v32[4 - 1] = x->v32[4 - 1 - base_index];
+        for (i = 4 - 1; i > base_index; i--)
+            x->v32[i - 1] = x->v32[i - 1 - base_index];
+
+    } else {
+        /* set each word to the "or" of the two bit-shifted words */
+        for (i = 4; i > base_index; i--) {
+            from = i - 1 - base_index;
+            b = x->v32[from] << bit_index;
+            if (from > 0)
+                b |= x->v32[from - 1] >> (32 - bit_index);
+            x->v32[i - 1] = b;
+        }
+    }
+
+    /* now wrap up the final portion */
+    for (i = 0; i < base_index; i++)
+        x->v32[i] = 0;
+}
+
+void v128_left_shift(v128_t *x, int shift)
+{
+    int i;
+    const int base_index = shift >> 5;
+    const int bit_index = shift & 31;
+
+    if (shift > 127) {
+        v128_set_to_zero(x);
+        return;
+    }
+
+    if (bit_index == 0) {
+        for (i = 0; i < 4 - base_index; i++)
+            x->v32[i] = x->v32[i + base_index];
+    } else {
+        for (i = 0; i < 4 - base_index - 1; i++)
+            x->v32[i] = (x->v32[i + base_index] >> bit_index) ^
+                        (x->v32[i + base_index + 1] << (32 - bit_index));
+        x->v32[4 - base_index - 1] = x->v32[4 - 1] >> bit_index;
+    }
+
+    /* now wrap up the final portion */
+    for (i = 4 - base_index; i < 4; i++)
+        x->v32[i] = 0;
+}
+
+/* functions manipulating bitvector_t */
+
+#ifndef DATATYPES_USE_MACROS /* little functions are not macros */
+
+int bitvector_get_bit(const bitvector_t *v, int bit_index)
+{
+    return _bitvector_get_bit(v, bit_index);
+}
+
+void bitvector_set_bit(bitvector_t *v, int bit_index)
+{
+    _bitvector_set_bit(v, bit_index);
+}
+
+void bitvector_clear_bit(bitvector_t *v, int bit_index)
+{
+    _bitvector_clear_bit(v, bit_index);
+}
+
+#endif /* DATATYPES_USE_MACROS */
+
+int bitvector_alloc(bitvector_t *v, unsigned long length)
+{
+    unsigned long l;
+
+    /* Round length up to a multiple of bits_per_word */
+    length =
+        (length + bits_per_word - 1) & ~(unsigned long)((bits_per_word - 1));
+
+    l = length / bits_per_word * bytes_per_word;
+
+    /* allocate memory, then set parameters */
+    if (l == 0) {
+        v->word = NULL;
+        v->length = 0;
+        return -1;
+    } else {
+        v->word = (uint32_t *)srtp_crypto_alloc(l);
+        if (v->word == NULL) {
+            v->length = 0;
+            return -1;
+        }
+    }
+    v->length = length;
+
+    /* initialize bitvector to zero */
+    bitvector_set_to_zero(v);
+
+    return 0;
+}
+
+void bitvector_dealloc(bitvector_t *v)
+{
+    if (v->word != NULL)
+        srtp_crypto_free(v->word);
+    v->word = NULL;
+    v->length = 0;
+}
+
+void bitvector_set_to_zero(bitvector_t *x)
+{
+    /* C99 guarantees that memset(0) will set the value 0 for uint32_t */
+    memset(x->word, 0, x->length >> 3);
+}
+
+char *bitvector_bit_string(bitvector_t *x, char *buf, int len)
+{
+    int j, i;
+    uint32_t mask;
+
+    for (j = i = 0; j < (int)(x->length >> 5) && i < len - 1; j++) {
+        for (mask = 0x80000000; mask > 0; mask >>= 1) {
+            if (x->word[j] & mask)
+                buf[i] = '1';
+            else
+                buf[i] = '0';
+            ++i;
+            if (i >= len - 1)
+                break;
+        }
+    }
+    buf[i] = 0; /* null terminate string */
+
+    return buf;
+}
+
+void bitvector_left_shift(bitvector_t *x, int shift)
+{
+    int i;
+    const int base_index = shift >> 5;
+    const int bit_index = shift & 31;
+    const int word_length = x->length >> 5;
+
+    if (shift >= (int)x->length) {
+        bitvector_set_to_zero(x);
+        return;
+    }
+
+    if (bit_index == 0) {
+        for (i = 0; i < word_length - base_index; i++)
+            x->word[i] = x->word[i + base_index];
+    } else {
+        for (i = 0; i < word_length - base_index - 1; i++)
+            x->word[i] = (x->word[i + base_index] >> bit_index) ^
+                         (x->word[i + base_index + 1] << (32 - bit_index));
+        x->word[word_length - base_index - 1] =
+            x->word[word_length - 1] >> bit_index;
+    }
+
+    /* now wrap up the final portion */
+    for (i = word_length - base_index; i < word_length; i++)
+        x->word[i] = 0;
+}
+
+int srtp_octet_string_is_eq(uint8_t *a, uint8_t *b, int len)
+{
+    uint8_t *end = b + len;
+    uint8_t accumulator = 0;
+
+    /*
+     * We use this somewhat obscure implementation to try to ensure the running
+     * time only depends on len, even accounting for compiler optimizations.
+     * The accumulator ends up zero iff the strings are equal.
+     */
+    while (b < end)
+        accumulator |= (*a++ ^ *b++);
+
+    /* Return 1 if *not* equal. */
+    return accumulator != 0;
+}
+
+void srtp_cleanse(void *s, size_t len)
+{
+    volatile unsigned char *p = (volatile unsigned char *)s;
+    while (len--)
+        *p++ = 0;
+}
+
+void octet_string_set_to_zero(void *s, size_t len)
+{
+#if defined(OPENSSL) && !defined(OPENSSL_CLEANSE_BROKEN)
+    OPENSSL_cleanse(s, len);
+#else
+    srtp_cleanse(s, len);
+#endif
+}
+
+#ifdef TESTAPP_SOURCE
+
+static const char b64chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+                               "abcdefghijklmnopqrstuvwxyz0123456789+/";
+
+static int base64_block_to_octet_triple(char *out, char *in)
+{
+    unsigned char sextets[4] = { 0 };
+    int j = 0;
+    int i;
+
+    for (i = 0; i < 4; i++) {
+        char *p = strchr(b64chars, in[i]);
+        if (p != NULL)
+            sextets[i] = p - b64chars;
+        else
+            j++;
+    }
+
+    out[0] = (sextets[0] << 2) | (sextets[1] >> 4);
+    if (j < 2)
+        out[1] = (sextets[1] << 4) | (sextets[2] >> 2);
+    if (j < 1)
+        out[2] = (sextets[2] << 6) | sextets[3];
+    return j;
+}
+
+int base64_string_to_octet_string(char *out, int *pad, char *in, int len)
+{
+    int k = 0;
+    int i = 0;
+    int j = 0;
+    if (len % 4 != 0)
+        return 0;
+
+    while (i < len && j == 0) {
+        j = base64_block_to_octet_triple(out + k, in + i);
+        k += 3;
+        i += 4;
+    }
+    *pad = j;
+    return i;
+}
+
+#endif

trunk/3rdparty/libsrtp-2-fit/crypto/math/stat.c

@@ -0,0 +1,213 @@
+/*
+ * stats.c
+ *
+ * statistical tests
+ *
+ * David A. McGrew
+ * Cisco Systems, Inc.
+ */
+
+/*
+ *
+ * Copyright (c) 2001-2017, 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 srtp_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(srtp_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(srtp_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(srtp_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(srtp_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(srtp_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(srtp_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 (srtp_mod_stat.on) {
+        debug_print0(srtp_mod_stat, "runs test");
+        for (i = 0; i < 6; i++)
+            debug_print(srtp_mod_stat, "  runs[]: %d", runs[i]);
+        for (i = 0; i < 6; i++)
+            debug_print(srtp_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;
+}