From 20d4a472800cbc9338f0c6c9c3dfce8eb13663c7 Mon Sep 17 00:00:00 2001
From: Dimitri Staessens <dimitri@ouroboros.rocks>
Date: Sat, 25 Apr 2026 22:46:05 +0200
Subject: 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>
---
 src/lib/hash.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'src/lib/hash.c')

diff --git a/src/lib/hash.c b/src/lib/hash.c
index 7adee968..f32001d9 100644
--- a/src/lib/hash.c
+++ b/src/lib/hash.c
@@ -39,6 +39,7 @@
 #include <ouroboros/md5.h>
 #include <ouroboros/sha3.h>
 #endif
+#include <ouroboros/crc64.h>
 #include <string.h>
 #include <assert.h>
 #include <stdbool.h>
@@ -69,6 +70,8 @@ int hash_len_tbl [] = {
 
 uint16_t hash_len(enum hash_algo algo)
 {
+        if (algo == HASH_CRC64)
+                return CRC64_HASH_LEN;
 #ifdef HAVE_LIBGCRYPT
         return (uint16_t) gcry_md_get_algo_dlen(gcry_algo_tbl[algo]);
 #else
@@ -81,6 +84,13 @@ void mem_hash(enum hash_algo  algo,
               const uint8_t * buf,
               size_t          len)
 {
+        if (algo == HASH_CRC64) {
+                uint64_t crc = 0;
+
+                crc64_nvme(&crc, buf, len);
+                *(uint64_t *) dst = htobe64(crc);
+                return;
+        }
 #ifdef HAVE_LIBGCRYPT
         gcry_md_hash_buffer(gcry_algo_tbl[algo], dst, buf, len);
 #else
-- 
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