lib: Add CRC-64/NVMe checksum

Add CRC-64/NVMe implementation with compile-time hardware backend
selection:

  x86 PCLMUL+SSE4.1 fold-by-16 (HAVE_PCLMUL)
  aarch64 PMULL fold-by-16 when (HAVE_PMULL)

and a byte-table fallback.

It's added as HASH_CRC64 to enum hash_algo (in the internal-use-only
section after HASH_MD5). Both mem_hash() and hash_len() early-return
for HASH_CRC64 because libgcrypt has no CRC-64/NVMe.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

3 files changed, 165 insertions, 0 deletions

diff --git a/src/lib/tests/CMakeLists.txt b/src/lib/tests/CMakeLists.txt
index 5a2f2c52..417ec4b0 100644
--- a/src/lib/tests/CMakeLists.txt
+++ b/src/lib/tests/CMakeLists.txt
@@ -11,6 +11,7 @@ create_test_sourcelist(${PARENT_DIR}_tests test_suite.c
   bitmap_test.c
   btree_test.c
   crc32_test.c
+  crc64_test.c
   crypt_test.c
   hash_test.c
   kex_test.c
diff --git a/src/lib/tests/crc64_test.c b/src/lib/tests/crc64_test.c
new file mode 100644
index 00000000..cf3f5ca3
--- /dev/null
+++ b/src/lib/tests/crc64_test.c
@@ -0,0 +1,126 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2026
+ *
+ * Test of the CRC-64/NVMe function
+ *
+ *    Dimitri Staessens <dimitri@ouroboros.rocks>
+ *    Sander Vrijders   <sander@ouroboros.rocks>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#include "config.h"
+
+#include <ouroboros/crc64.h>
+#include <ouroboros/random.h>
+
+#include <test/test.h>
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+
+/* Reference impl, internal to libouroboros-common. */
+extern void crc64_nvme_table(uint64_t *   crc,
+                             const void * buf,
+                             size_t       len);
+
+/* reveng-catalog smoke vectors plus a 16-byte fold-boundary check. */
+static int test_crc64_nvme_basic(void)
+{
+        uint64_t crc;
+
+        TEST_START();
+
+        crc = 0;
+        crc64_nvme(&crc, "", 0);
+        if (crc != 0x0000000000000000ULL)
+                goto fail;
+
+        crc = 0;
+        crc64_nvme(&crc, "123456789", 9);
+        if (crc != 0xae8b14860a799888ULL)
+                goto fail;
+
+        crc = 0;
+        crc64_nvme(&crc, "0123456789abcdef", 16);
+        if (crc != 0x091485ca7018730eULL)
+                goto fail;
+
+        TEST_SUCCESS();
+        return TEST_RC_SUCCESS;
+ fail:
+        TEST_FAIL();
+        return TEST_RC_FAIL;
+}
+
+#if defined(HAVE_PCLMUL) || defined(HAVE_PMULL)
+/* Cross-check the accelerated dispatcher path against the byte-table. */
+static int test_crc64_nvme_random(void)
+{
+        static const size_t lens[] = {
+                0, 1, 7, 8, 15, 16, 17, 31, 32, 33, 63, 64, 65, 127, 128,
+                129, 255, 256, 257, 1023, 1024, 1025, 4096
+        };
+        uint8_t  buf[4096];
+        size_t   i;
+        uint64_t ref;
+        uint64_t got;
+
+        TEST_START();
+
+        if (random_buffer(buf, sizeof(buf)) < 0) {
+                printf("Failed to generate random data.\n");
+                goto fail;
+        }
+
+        for (i = 0; i < sizeof(lens) / sizeof(lens[0]); i++) {
+                ref = 0;
+                crc64_nvme_table(&ref, buf, lens[i]);
+
+                got = 0;
+                crc64_nvme(&got, buf, lens[i]);
+
+                if (ref == got)
+                        continue;
+
+                printf("Mismatch at len=%zu: table=0x%016lx disp=0x%016lx\n",
+                        lens[i],
+                        (unsigned long) ref,
+                        (unsigned long) got);
+                goto fail;
+        }
+
+        TEST_SUCCESS();
+        return TEST_RC_SUCCESS;
+ fail:
+        TEST_FAIL();
+        return TEST_RC_FAIL;
+#endif
+}
+
+int crc64_test(int     argc,
+               char ** argv)
+{
+        int ret = 0;
+
+        (void) argc;
+        (void) argv;
+
+        ret |= test_crc64_nvme_basic();
+#if defined(HAVE_PCLMUL) || defined(HAVE_PMULL)
+        ret |= test_crc64_nvme_random();
+#endif
+        return ret;
+}
diff --git a/src/lib/tests/hash_test.c b/src/lib/tests/hash_test.c
index e43847e1..19343b17 100644
--- a/src/lib/tests/hash_test.c
+++ b/src/lib/tests/hash_test.c
@@ -74,6 +74,42 @@ static int test_crc32(void)
         return ret;
 }
 
+static int test_crc64(void)
+{
+        int ret = 0;
+
+        struct vec_entry vec [] = {
+                { "",          "0000000000000000" },
+                { "123456789", "ae8b14860a799888" },
+                { "0123456789abcdef",
+                               "091485ca7018730e" },
+                { NULL,        NULL               }
+        };
+
+        struct vec_entry * cur = vec;
+
+        TEST_START();
+
+        while (cur->in != NULL) {
+                uint8_t crc[8];
+                char    res[17];
+
+                str_hash(HASH_CRC64, crc, cur->in);
+
+                sprintf(res, HASH_FMT64, HASH_VAL64(crc));
+                if (strcmp(res, cur->out) != 0) {
+                        printf("Hash failed %s != %s.\n", res, cur->out);
+                        ret |= -1;
+                }
+
+                ++cur;
+        }
+
+        TEST_END(ret);
+
+        return ret;
+}
+
 static int test_md5(void)
 {
         int ret = 0;
@@ -194,6 +230,8 @@ int hash_test(int     argc,
 
         ret |= test_crc32();
 
+        ret |= test_crc64();
+
         ret |= test_md5();
 
         ret |= test_sha3();