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-rw-r--r--src/lib/intmath/.may_include4
-rw-r--r--src/lib/intmath/addsub.c20
-rw-r--r--src/lib/intmath/addsub.h13
-rw-r--r--src/lib/intmath/bits.c88
-rw-r--r--src/lib/intmath/bits.h16
-rw-r--r--src/lib/intmath/cmp.h33
-rw-r--r--src/lib/intmath/include.am25
-rw-r--r--src/lib/intmath/logic.h14
-rw-r--r--src/lib/intmath/muldiv.c75
-rw-r--r--src/lib/intmath/muldiv.h22
-rw-r--r--src/lib/intmath/weakrng.c51
-rw-r--r--src/lib/intmath/weakrng.h25
12 files changed, 386 insertions, 0 deletions
diff --git a/src/lib/intmath/.may_include b/src/lib/intmath/.may_include
new file mode 100644
index 0000000000..d96c112220
--- /dev/null
+++ b/src/lib/intmath/.may_include
@@ -0,0 +1,4 @@
+orconfig.h
+lib/cc/*.h
+lib/err/*.h
+lib/intmath/*.h
diff --git a/src/lib/intmath/addsub.c b/src/lib/intmath/addsub.c
new file mode 100644
index 0000000000..816c5a2bd7
--- /dev/null
+++ b/src/lib/intmath/addsub.c
@@ -0,0 +1,20 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "lib/intmath/addsub.h"
+#include "lib/cc/compat_compiler.h"
+
+/* Helper: safely add two uint32_t's, capping at UINT32_MAX rather
+ * than overflow */
+uint32_t
+tor_add_u32_nowrap(uint32_t a, uint32_t b)
+{
+ /* a+b > UINT32_MAX check, without overflow */
+ if (PREDICT_UNLIKELY(a > UINT32_MAX - b)) {
+ return UINT32_MAX;
+ } else {
+ return a+b;
+ }
+}
diff --git a/src/lib/intmath/addsub.h b/src/lib/intmath/addsub.h
new file mode 100644
index 0000000000..5277adfa49
--- /dev/null
+++ b/src/lib/intmath/addsub.h
@@ -0,0 +1,13 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_INTMATH_ADDSUB_H
+#define TOR_INTMATH_ADDSUB_H
+
+#include "lib/cc/torint.h"
+
+uint32_t tor_add_u32_nowrap(uint32_t a, uint32_t b);
+
+#endif /* !defined(TOR_INTMATH_MULDIV_H) */
diff --git a/src/lib/intmath/bits.c b/src/lib/intmath/bits.c
new file mode 100644
index 0000000000..85d901f71b
--- /dev/null
+++ b/src/lib/intmath/bits.c
@@ -0,0 +1,88 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "lib/intmath/bits.h"
+
+/** Returns floor(log2(u64)). If u64 is 0, (incorrectly) returns 0. */
+int
+tor_log2(uint64_t u64)
+{
+ int r = 0;
+ if (u64 >= (U64_LITERAL(1)<<32)) {
+ u64 >>= 32;
+ r = 32;
+ }
+ if (u64 >= (U64_LITERAL(1)<<16)) {
+ u64 >>= 16;
+ r += 16;
+ }
+ if (u64 >= (U64_LITERAL(1)<<8)) {
+ u64 >>= 8;
+ r += 8;
+ }
+ if (u64 >= (U64_LITERAL(1)<<4)) {
+ u64 >>= 4;
+ r += 4;
+ }
+ if (u64 >= (U64_LITERAL(1)<<2)) {
+ u64 >>= 2;
+ r += 2;
+ }
+ if (u64 >= (U64_LITERAL(1)<<1)) {
+ // u64 >>= 1; // not using this any more.
+ r += 1;
+ }
+ return r;
+}
+
+/** Return the power of 2 in range [1,UINT64_MAX] closest to <b>u64</b>. If
+ * there are two powers of 2 equally close, round down. */
+uint64_t
+round_to_power_of_2(uint64_t u64)
+{
+ int lg2;
+ uint64_t low;
+ uint64_t high;
+ if (u64 == 0)
+ return 1;
+
+ lg2 = tor_log2(u64);
+ low = U64_LITERAL(1) << lg2;
+
+ if (lg2 == 63)
+ return low;
+
+ high = U64_LITERAL(1) << (lg2+1);
+ if (high - u64 < u64 - low)
+ return high;
+ else
+ return low;
+}
+
+/** Return the number of bits set in <b>v</b>. */
+int
+n_bits_set_u8(uint8_t v)
+{
+ static const int nybble_table[] = {
+ 0, /* 0000 */
+ 1, /* 0001 */
+ 1, /* 0010 */
+ 2, /* 0011 */
+ 1, /* 0100 */
+ 2, /* 0101 */
+ 2, /* 0110 */
+ 3, /* 0111 */
+ 1, /* 1000 */
+ 2, /* 1001 */
+ 2, /* 1010 */
+ 3, /* 1011 */
+ 2, /* 1100 */
+ 3, /* 1101 */
+ 3, /* 1110 */
+ 4, /* 1111 */
+ };
+
+ return nybble_table[v & 15] + nybble_table[v>>4];
+}
diff --git a/src/lib/intmath/bits.h b/src/lib/intmath/bits.h
new file mode 100644
index 0000000000..70f855089c
--- /dev/null
+++ b/src/lib/intmath/bits.h
@@ -0,0 +1,16 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_INTMATH_BITS_H
+#define TOR_INTMATH_BITS_H
+
+#include "lib/cc/torint.h"
+#include "lib/cc/compat_compiler.h"
+
+int tor_log2(uint64_t u64) ATTR_CONST;
+uint64_t round_to_power_of_2(uint64_t u64);
+int n_bits_set_u8(uint8_t v);
+
+#endif /* !defined(TOR_INTMATH_BITS_H) */
diff --git a/src/lib/intmath/cmp.h b/src/lib/intmath/cmp.h
new file mode 100644
index 0000000000..627e5d18b4
--- /dev/null
+++ b/src/lib/intmath/cmp.h
@@ -0,0 +1,33 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_INTMATH_CMP_H
+#define TOR_INTMATH_CMP_H
+
+/** Macros for MIN/MAX. Never use these when the arguments could have
+ * side-effects.
+ * {With GCC extensions we could probably define a safer MIN/MAX. But
+ * depending on that safety would be dangerous, since not every platform
+ * has it.}
+ **/
+#ifndef MAX
+#define MAX(a,b) ( ((a)<(b)) ? (b) : (a) )
+#endif
+#ifndef MIN
+#define MIN(a,b) ( ((a)>(b)) ? (b) : (a) )
+#endif
+
+/* Return <b>v</b> if it's between <b>min</b> and <b>max</b>. Otherwise
+ * return <b>min</b> if <b>v</b> is smaller than <b>min</b>, or <b>max</b> if
+ * <b>b</b> is larger than <b>max</b>.
+ *
+ * Requires that <b>min</b> is no more than <b>max</b>. May evaluate any of
+ * its arguments more than once! */
+#define CLAMP(min,v,max) \
+ ( ((v) < (min)) ? (min) : \
+ ((v) > (max)) ? (max) : \
+ (v) )
+
+#endif /* !defined(TOR_INTMATH_CMP_H) */
diff --git a/src/lib/intmath/include.am b/src/lib/intmath/include.am
new file mode 100644
index 0000000000..45ee3bd53b
--- /dev/null
+++ b/src/lib/intmath/include.am
@@ -0,0 +1,25 @@
+
+noinst_LIBRARIES += src/lib/libtor-intmath.a
+
+if UNITTESTS_ENABLED
+noinst_LIBRARIES += src/lib/libtor-intmath-testing.a
+endif
+
+src_lib_libtor_intmath_a_SOURCES = \
+ src/lib/intmath/addsub.c \
+ src/lib/intmath/bits.c \
+ src/lib/intmath/muldiv.c \
+ src/lib/intmath/weakrng.c
+
+src_lib_libtor_intmath_testing_a_SOURCES = \
+ $(src_lib_libtor_intmath_a_SOURCES)
+src_lib_libtor_intmath_testing_a_CPPFLAGS = $(AM_CPPFLAGS) $(TEST_CPPFLAGS)
+src_lib_libtor_intmath_testing_a_CFLAGS = $(AM_CFLAGS) $(TEST_CFLAGS)
+
+noinst_HEADERS += \
+ src/lib/intmath/addsub.h \
+ src/lib/intmath/cmp.h \
+ src/lib/intmath/bits.h \
+ src/lib/intmath/logic.h \
+ src/lib/intmath/muldiv.h \
+ src/lib/intmath/weakrng.h
diff --git a/src/lib/intmath/logic.h b/src/lib/intmath/logic.h
new file mode 100644
index 0000000000..0510a621dc
--- /dev/null
+++ b/src/lib/intmath/logic.h
@@ -0,0 +1,14 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef HAVE_TOR_LOGIC_H
+#define HAVE_TOR_LOGIC_H
+
+/** Macro: true if two values have the same boolean value. */
+#define bool_eq(a,b) (!(a)==!(b))
+/** Macro: true if two values have different boolean values. */
+#define bool_neq(a,b) (!(a)!=!(b))
+
+#endif
diff --git a/src/lib/intmath/muldiv.c b/src/lib/intmath/muldiv.c
new file mode 100644
index 0000000000..3e627b237a
--- /dev/null
+++ b/src/lib/intmath/muldiv.c
@@ -0,0 +1,75 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "lib/intmath/muldiv.h"
+#include "lib/err/torerr.h"
+
+#include <stdlib.h>
+
+/** Return the lowest x such that x is at least <b>number</b>, and x modulo
+ * <b>divisor</b> == 0. If no such x can be expressed as an unsigned, return
+ * UINT_MAX. Asserts if divisor is zero. */
+unsigned
+round_to_next_multiple_of(unsigned number, unsigned divisor)
+{
+ raw_assert(divisor > 0);
+ if (UINT_MAX - divisor + 1 < number)
+ return UINT_MAX;
+ number += divisor - 1;
+ number -= number % divisor;
+ return number;
+}
+
+/** Return the lowest x such that x is at least <b>number</b>, and x modulo
+ * <b>divisor</b> == 0. If no such x can be expressed as a uint32_t, return
+ * UINT32_MAX. Asserts if divisor is zero. */
+uint32_t
+round_uint32_to_next_multiple_of(uint32_t number, uint32_t divisor)
+{
+ raw_assert(divisor > 0);
+ if (UINT32_MAX - divisor + 1 < number)
+ return UINT32_MAX;
+
+ number += divisor - 1;
+ number -= number % divisor;
+ return number;
+}
+
+/** Return the lowest x such that x is at least <b>number</b>, and x modulo
+ * <b>divisor</b> == 0. If no such x can be expressed as a uint64_t, return
+ * UINT64_MAX. Asserts if divisor is zero. */
+uint64_t
+round_uint64_to_next_multiple_of(uint64_t number, uint64_t divisor)
+{
+ raw_assert(divisor > 0);
+ if (UINT64_MAX - divisor + 1 < number)
+ return UINT64_MAX;
+ number += divisor - 1;
+ number -= number % divisor;
+ return number;
+}
+
+/* Helper: return greatest common divisor of a,b */
+static uint64_t
+gcd64(uint64_t a, uint64_t b)
+{
+ while (b) {
+ uint64_t t = b;
+ b = a % b;
+ a = t;
+ }
+ return a;
+}
+
+/* Given a fraction *<b>numer</b> / *<b>denom</b>, simplify it.
+ * Requires that the denominator is greater than 0. */
+void
+simplify_fraction64(uint64_t *numer, uint64_t *denom)
+{
+ raw_assert(denom);
+ uint64_t gcd = gcd64(*numer, *denom);
+ *numer /= gcd;
+ *denom /= gcd;
+}
diff --git a/src/lib/intmath/muldiv.h b/src/lib/intmath/muldiv.h
new file mode 100644
index 0000000000..de76d9eb68
--- /dev/null
+++ b/src/lib/intmath/muldiv.h
@@ -0,0 +1,22 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_INTMATH_MULDIV_H
+#define TOR_INTMATH_MULDIV_H
+
+#include "lib/cc/torint.h"
+
+unsigned round_to_next_multiple_of(unsigned number, unsigned divisor);
+uint32_t round_uint32_to_next_multiple_of(uint32_t number, uint32_t divisor);
+uint64_t round_uint64_to_next_multiple_of(uint64_t number, uint64_t divisor);
+
+void simplify_fraction64(uint64_t *numer, uint64_t *denom);
+
+/* Compute the CEIL of <b>a</b> divided by <b>b</b>, for nonnegative <b>a</b>
+ * and positive <b>b</b>. Works on integer types only. Not defined if a+(b-1)
+ * can overflow. */
+#define CEIL_DIV(a,b) (((a)+((b)-1))/(b))
+
+#endif /* !defined(TOR_INTMATH_MULDIV_H) */
diff --git a/src/lib/intmath/weakrng.c b/src/lib/intmath/weakrng.c
new file mode 100644
index 0000000000..2ecab97cc1
--- /dev/null
+++ b/src/lib/intmath/weakrng.c
@@ -0,0 +1,51 @@
+/* Copyright (c) 2003, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "lib/intmath/weakrng.h"
+#include "lib/err/torerr.h"
+
+#include <stdlib.h>
+
+/** Initialize the insecure RNG <b>rng</b> from a seed value <b>seed</b>. */
+void
+tor_init_weak_random(tor_weak_rng_t *rng, unsigned seed)
+{
+ rng->state = (uint32_t)(seed & 0x7fffffff);
+}
+
+/** Return a randomly chosen value in the range 0..TOR_WEAK_RANDOM_MAX based
+ * on the RNG state of <b>rng</b>. This entropy will not be cryptographically
+ * strong; do not rely on it for anything an adversary should not be able to
+ * predict. */
+int32_t
+tor_weak_random(tor_weak_rng_t *rng)
+{
+ /* Here's a linear congruential generator. OpenBSD and glibc use these
+ * parameters; they aren't too bad, and should have maximal period over the
+ * range 0..INT32_MAX. We don't want to use the platform rand() or random(),
+ * since some platforms have bad weak RNGs that only return values in the
+ * range 0..INT16_MAX, which just isn't enough. */
+ rng->state = (rng->state * 1103515245 + 12345) & 0x7fffffff;
+ return (int32_t) rng->state;
+}
+
+/** Return a random number in the range [0 , <b>top</b>). {That is, the range
+ * of integers i such that 0 <= i < top.} Chooses uniformly. Requires that
+ * top is greater than 0. This randomness is not cryptographically strong; do
+ * not rely on it for anything an adversary should not be able to predict. */
+int32_t
+tor_weak_random_range(tor_weak_rng_t *rng, int32_t top)
+{
+ /* We don't want to just do tor_weak_random() % top, since random() is often
+ * implemented with an LCG whose modulus is a power of 2, and those are
+ * cyclic in their low-order bits. */
+ int divisor, result;
+ raw_assert(top > 0);
+ divisor = TOR_WEAK_RANDOM_MAX / top;
+ do {
+ result = (int32_t)(tor_weak_random(rng) / divisor);
+ } while (result >= top);
+ return result;
+}
diff --git a/src/lib/intmath/weakrng.h b/src/lib/intmath/weakrng.h
new file mode 100644
index 0000000000..e5a88b30fe
--- /dev/null
+++ b/src/lib/intmath/weakrng.h
@@ -0,0 +1,25 @@
+/* Copyright (c) 2003, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_WEAKRNG_H
+#define TOR_WEAKRNG_H
+
+#include "lib/cc/torint.h"
+
+/* ===== Insecure rng */
+typedef struct tor_weak_rng_t {
+ uint32_t state;
+} tor_weak_rng_t;
+
+#define TOR_WEAK_RNG_INIT {383745623}
+#define TOR_WEAK_RANDOM_MAX (INT_MAX)
+void tor_init_weak_random(tor_weak_rng_t *weak_rng, unsigned seed);
+int32_t tor_weak_random(tor_weak_rng_t *weak_rng);
+int32_t tor_weak_random_range(tor_weak_rng_t *rng, int32_t top);
+/** Randomly return true according to <b>rng</b> with probability 1 in
+ * <b>n</b> */
+#define tor_weak_random_one_in_n(rng, n) (0==tor_weak_random_range((rng),(n)))
+
+#endif
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