1 files changed, 63 insertions, 0 deletions
diff --git a/crypto/evp/dh_support.c b/crypto/evp/dh_support.c
new file mode 100644
index 000000000000..87296ffbee2b
--- /dev/null
+++ b/crypto/evp/dh_support.c
@@ -0,0 +1,63 @@
+/*
+ * Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <string.h> /* strcmp */
+#include <openssl/dh.h>
+#include "internal/nelem.h"
+#include "crypto/dh.h"
+
+typedef struct dh_name2id_st{
+    const char *name;
+    int id;
+    int type;
+} DH_GENTYPE_NAME2ID;
+
+/* Indicates that the paramgen_type can be used for either DH or DHX */
+#define TYPE_ANY -1
+#ifndef OPENSSL_NO_DH
+# define TYPE_DH    DH_FLAG_TYPE_DH
+# define TYPE_DHX   DH_FLAG_TYPE_DHX
+#else
+# define TYPE_DH    0
+# define TYPE_DHX   0
+#endif
+
+static const DH_GENTYPE_NAME2ID dhtype2id[] =
+{
+    { "group", DH_PARAMGEN_TYPE_GROUP, TYPE_ANY },
+    { "generator", DH_PARAMGEN_TYPE_GENERATOR, TYPE_DH },
+    { "fips186_4", DH_PARAMGEN_TYPE_FIPS_186_4, TYPE_DHX },
+    { "fips186_2", DH_PARAMGEN_TYPE_FIPS_186_2, TYPE_DHX },
+};
+
+const char *ossl_dh_gen_type_id2name(int id)
+{
+    size_t i;
+
+    for (i = 0; i < OSSL_NELEM(dhtype2id); ++i) {
+        if (dhtype2id[i].id == id)
+            return dhtype2id[i].name;
+    }
+    return NULL;
+}
+
+#ifndef OPENSSL_NO_DH
+int ossl_dh_gen_type_name2id(const char *name, int type)
+{
+    size_t i;
+
+    for (i = 0; i < OSSL_NELEM(dhtype2id); ++i) {
+        if ((dhtype2id[i].type == TYPE_ANY
+             || type == dhtype2id[i].type)
+            && strcmp(dhtype2id[i].name, name) == 0)
+            return dhtype2id[i].id;
+    }
+    return -1;
+}
+#endif