Move FFDH helper functions and macros to more suitable locations

Signed-off-by: Przemek Stekiel <przemyslaw.stekiel@mobica.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 4b73b41..b10a563 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -221,6 +221,12 @@
 #define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE4096     0x0102
 #define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE6144     0x0103
 #define MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE8192     0x0104
+/* Finite Field Group Names (DHE) */
+#define MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE2048     "ffdhe2048"
+#define MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE3072     "ffdhe3072"
+#define MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE4096     "ffdhe4096"
+#define MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE6144     "ffdhe6144"
+#define MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE8192     "ffdhe8192"
 
 /*
  * TLS 1.3 Key Exchange Modes
@@ -5333,4 +5339,23 @@
 }
 #endif
 
+static inline const char *mbedtls_ssl_ffdh_name_from_group(uint16_t group)
+{
+    switch (group) {
+        case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE2048:
+            return MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE2048;
+        case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE3072:
+            return MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE3072;
+        case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE4096:
+            return MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE4096;
+        case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE6144:
+            return MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE6144;
+        case MBEDTLS_SSL_IANA_TLS_GROUP_FFDHE8192:
+            return MBEDTLS_SSL_IANA_TLS_GROUP_NAME_FFDHE8192;
+        default:
+            return NULL;
+    }
+    return NULL;
+}
+
 #endif /* ssl.h */