1 files changed, 105 insertions, 0 deletions
diff --git a/src/libdnssec/digest.c b/src/libdnssec/digest.c
new file mode 100644
index 0000000..83a4fcb
--- /dev/null
+++ b/src/libdnssec/digest.c
@@ -0,0 +1,105 @@
+/*  Copyright (C) 2021 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    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, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "libdnssec/digest.h"
+
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+
+#include "libdnssec/shared/shared.h"
+
+struct dnssec_digest_ctx {
+	gnutls_hash_hd_t gtctx;
+	unsigned size;
+};
+
+static gnutls_digest_algorithm_t lookup_algorithm(dnssec_digest_t algorithm)
+{
+	switch (algorithm) {
+	case DNSSEC_DIGEST_SHA384: return GNUTLS_DIG_SHA384;
+	case DNSSEC_DIGEST_SHA512: return GNUTLS_DIG_SHA512;
+	default:
+		return GNUTLS_DIG_UNKNOWN;
+	};
+}
+
+_public_
+int dnssec_digest_init(dnssec_digest_t algorithm, dnssec_digest_ctx_t **out_ctx)
+{
+	if (out_ctx == NULL) {
+		return DNSSEC_EINVAL;
+	}
+
+	gnutls_digest_algorithm_t gtalg = lookup_algorithm(algorithm);
+	if (gtalg == GNUTLS_DIG_UNKNOWN) {
+		return DNSSEC_INVALID_DIGEST_ALGORITHM;
+	}
+
+	dnssec_digest_ctx_t *res = malloc(sizeof(*res));
+	if (res == NULL) {
+		return DNSSEC_ENOMEM;
+	}
+
+	res->size = gnutls_hash_get_len(gtalg);
+	if (res->size == 0 || gnutls_hash_init(&res->gtctx, gtalg) < 0) {
+		free(res);
+		return DNSSEC_DIGEST_ERROR;
+	}
+
+	*out_ctx = res;
+	return DNSSEC_EOK;
+}
+
+static void digest_ctx_free(dnssec_digest_ctx_t *ctx)
+{
+	free_gnutls_hash_ptr(&ctx->gtctx);
+	free(ctx);
+}
+
+_public_
+int dnssec_digest(dnssec_digest_ctx_t *ctx, dnssec_binary_t *data)
+{
+	if (ctx == NULL || data == NULL) {
+		return DNSSEC_EINVAL;
+	}
+
+	int r = gnutls_hash(ctx->gtctx, data->data, data->size);
+	if (r != 0) {
+		digest_ctx_free(ctx);
+		return DNSSEC_DIGEST_ERROR;
+	}
+	return DNSSEC_EOK;
+}
+
+_public_
+int dnssec_digest_finish(dnssec_digest_ctx_t *ctx, dnssec_binary_t *out)
+{
+	if (ctx == NULL || out == NULL) {
+		return DNSSEC_EINVAL;
+	}
+
+	int r = dnssec_binary_resize(out, ctx->size);
+	if (r < 0) {
+		dnssec_binary_free(out);
+		digest_ctx_free(ctx);
+		return r;
+	}
+
+	gnutls_hash_output(ctx->gtctx, out->data);
+
+	digest_ctx_free(ctx);
+	return DNSSEC_EOK;
+}