From ebb2b055cc95ac1bdfd5eea075b62dc4c3f056cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@isc.org>
Date: Thu, 16 Jul 2020 17:29:44 +0200
Subject: [PATCH] Add isc_hash32() and rename isc_hash_function() to
 isc_hash64()

As the names suggest the original isc_hash64 function returns 64-bit
long hash values and the isc_hash32() returns 32-bit values.

(cherry picked from commit f59fd49fd88e6efa966fd9c91a6ad319e1388679)
---
 lib/isc/hash.c              | 41 +++++++++++++++++++++++++++++--------
 lib/isc/include/isc/hash.h  | 14 +++++++------
 lib/isc/win32/libisc.def.in |  3 ++-
 3 files changed, 42 insertions(+), 16 deletions(-)

diff --git a/lib/isc/hash.c b/lib/isc/hash.c
index b00cd148cf..8ef93f5f94 100644
--- a/lib/isc/hash.c
+++ b/lib/isc/hash.c
@@ -9,10 +9,6 @@
  * information regarding copyright ownership.
  */
 
-/*
- * 32 bit Fowler/Noll/Vo FNV-1a hash code with modification for BIND
- */
-
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stddef.h>
@@ -32,21 +28,25 @@
 #include "isc/util.h"
 
 static uint8_t isc_hash_key[16];
+static uint8_t isc_hash32_key[8];
 static bool hash_initialized = false;
 static isc_once_t isc_hash_once = ISC_ONCE_INIT;
 
 static void
 isc_hash_initialize(void) {
-	uint64_t key[2] = { 0, 1 };
-#if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 	/*
 	 * Set a constant key to help in problem reproduction should
 	 * fuzzing find a crash or a hang.
 	 */
-#else  /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
+	uint64_t key[2] = { 0, 1 };
+#if !FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 	isc_entropy_get(key, sizeof(key));
 #endif /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
 	memmove(isc_hash_key, key, sizeof(isc_hash_key));
+#if !FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
+	isc_entropy_get(key, sizeof(key));
+#endif /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
+	memmove(isc_hash32_key, key, sizeof(isc_hash32_key));
 	hash_initialized = true;
 }
 
@@ -104,8 +104,7 @@ isc_hash_set_initializer(const void *initializer) {
 }
 
 uint64_t
-isc_hash_function(const void *data, const size_t length,
-		  const bool case_sensitive) {
+isc_hash64(const void *data, const size_t length, const bool case_sensitive) {
 	uint64_t hval;
 
 	REQUIRE(length == 0 || data != NULL);
@@ -126,3 +125,27 @@ isc_hash_function(const void *data, const size_t length,
 
 	return (hval);
 }
+
+uint32_t
+isc_hash32(const void *data, const size_t length, const bool case_sensitive) {
+	uint32_t hval;
+
+	REQUIRE(length == 0 || data != NULL);
+
+	RUNTIME_CHECK(isc_once_do(&isc_hash_once, isc_hash_initialize) ==
+		      ISC_R_SUCCESS);
+
+	if (case_sensitive) {
+		isc_halfsiphash24(isc_hash_key, data, length, (uint8_t *)&hval);
+	} else {
+		uint8_t input[1024];
+		REQUIRE(length <= 1024);
+		for (unsigned int i = 0; i < length; i++) {
+			input[i] = maptolower[((const uint8_t *)data)[i]];
+		}
+		isc_halfsiphash24(isc_hash_key, input, length,
+				  (uint8_t *)&hval);
+	}
+
+	return (hval);
+}
diff --git a/lib/isc/include/isc/hash.h b/lib/isc/include/isc/hash.h
index 3989d0449e..e2d36e1807 100644
--- a/lib/isc/include/isc/hash.h
+++ b/lib/isc/include/isc/hash.h
@@ -29,9 +29,12 @@ isc_hash_get_initializer(void);
 void
 isc_hash_set_initializer(const void *initializer);
 
+#define isc_hash_function isc_hash64
+
+uint32_t
+isc_hash32(const void *data, const size_t length, const bool case_sensitive);
 uint64_t
-isc_hash_function(const void *data, const size_t length,
-		  const bool case_sensitive);
+isc_hash64(const void *data, const size_t length, const bool case_sensitive);
 /*!<
  * \brief Calculate a hash over data.
  *
@@ -41,7 +44,7 @@ isc_hash_function(const void *data, const size_t length,
  * process using this library is run, but will have uniform
  * distribution.
  *
- * isc_hash_function() calculates the hash from start to end over the
+ * isc_hash_32/64() calculates the hash from start to end over the
  * input data.
  *
  * 'data' is the data to be hashed.
@@ -52,9 +55,8 @@ isc_hash_function(const void *data, const size_t length,
  * case_sensitive values.  It should typically be false if the hash key
  * is a DNS name.
  *
- * WARNING: In case of case insensitive input, the input buffer cannot
- * be longer than 1024, which should be fine, as it is only used for
- * DNS names.
+ * Returns:
+ * \li 32 or 64-bit hash value
  */
 
 ISC_LANG_ENDDECLS
diff --git a/lib/isc/win32/libisc.def.in b/lib/isc/win32/libisc.def.in
index a1f2e961d9..8e948420df 100644
--- a/lib/isc/win32/libisc.def.in
+++ b/lib/isc/win32/libisc.def.in
@@ -238,7 +238,8 @@ isc_fsaccess_add
 isc_fsaccess_changeowner
 isc_fsaccess_remove
 isc_fsaccess_set
-isc_hash_function
+isc_hash32
+isc_hash64
 isc_hash_get_initializer
 isc_hash_set_initializer
 isc_heap_create