--- a/svr-runopts.c	Thu Mar 21 23:28:59 2019 +0800
+++ b/svr-runopts.c	Fri Jun 26 21:07:34 2020 +0800
@@ -46,16 +46,19 @@
 					"-b bannerfile	Display the contents of bannerfile"
 					" before user login\n"
 					"		(default: none)\n"
-					"-r keyfile  Specify hostkeys (repeatable)\n"
+					"-r keyfile      Specify hostkeys (repeatable)\n"
 					"		defaults: \n"
 #if DROPBEAR_DSS
-					"		dss %s\n"
+					"		- dss %s\n"
 #endif
 #if DROPBEAR_RSA
-					"		rsa %s\n"
+					"		- rsa %s\n"
 #endif
 #if DROPBEAR_ECDSA
-					"		ecdsa %s\n"
+					"		- ecdsa %s\n"
+#endif
+#if DROPBEAR_ED25519
+					"		- ed25519 %s\n"
 #endif
 #if DROPBEAR_DELAY_HOSTKEY
 					"-R		Create hostkeys as required\n" 
@@ -99,6 +102,10 @@
 					"-W <receive_window_buffer> (default %d, larger may be faster, max 1MB)\n"
 					"-K <keepalive>  (0 is never, default %d, in seconds)\n"
 					"-I <idle_timeout>  (0 is never, default %d, in seconds)\n"
+#if DROPBEAR_PLUGIN
+                                        "-A <authplugin>[,<options>]\n"
+                                        "               Enable external public key auth through <authplugin>\n"
+#endif
 					"-V    Version\n"
 #if DEBUG_TRACE
 					"-v		verbose (compiled with DEBUG_TRACE)\n"
@@ -113,6 +120,9 @@
 #if DROPBEAR_ECDSA
 					ECDSA_PRIV_FILENAME,
 #endif
+#if DROPBEAR_ED25519
+					ED25519_PRIV_FILENAME,
+#endif
 					MAX_AUTH_TRIES,
 					DROPBEAR_MAX_PORTS, DROPBEAR_DEFPORT, DROPBEAR_PIDFILE,
 					DEFAULT_RECV_WINDOW, DEFAULT_KEEPALIVE, DEFAULT_IDLE_TIMEOUT);
@@ -129,6 +139,9 @@
 	char* maxauthtries_arg = NULL;
 	char* keyfile = NULL;
 	char c;
+#if DROPBEAR_PLUGIN
+        char* pubkey_plugin = NULL;
+#endif
 
 
 	/* see printhelp() for options */
@@ -156,6 +169,10 @@
 #if DROPBEAR_SVR_REMOTETCPFWD
 	svr_opts.noremotetcp = 0;
 #endif
+#if DROPBEAR_PLUGIN
+        svr_opts.pubkey_plugin = NULL;
+        svr_opts.pubkey_plugin_options = NULL;
+#endif
 
 #ifndef DISABLE_ZLIB
 	opts.compress_mode = DROPBEAR_COMPRESS_DELAYED;
@@ -274,6 +291,11 @@
 				case 'u':
 					/* backwards compatibility with old urandom option */
 					break;
+#if DROPBEAR_PLUGIN
+                                case 'A':
+                                        next = &pubkey_plugin;
+                                        break;
+#endif
 #if DEBUG_TRACE
 				case 'v':
 					debug_trace = 1;
@@ -394,6 +416,17 @@
 	if (svr_opts.forced_command) {
 		dropbear_log(LOG_INFO, "Forced command set to '%s'", svr_opts.forced_command);
 	}
+#if DROPBEAR_PLUGIN
+        if (pubkey_plugin) {
+            char *args = strchr(pubkey_plugin, ',');
+            if (args) {
+                *args='\0';
+                ++args;
+            }
+            svr_opts.pubkey_plugin = pubkey_plugin;
+            svr_opts.pubkey_plugin_options = args;
+        }
+#endif
 }
 
 static void addportandaddress(const char* spec) {
@@ -452,9 +485,9 @@
 static void disablekey(int type) {
 	int i;
 	TRACE(("Disabling key type %d", type))
-	for (i = 0; sshhostkey[i].name != NULL; i++) {
-		if (sshhostkey[i].val == type) {
-			sshhostkey[i].usable = 0;
+	for (i = 0; sigalgs[i].name != NULL; i++) {
+		if (sigalgs[i].val == type) {
+			sigalgs[i].usable = 0;
 			break;
 		}
 	}
@@ -511,6 +544,13 @@
 	}
 #endif
 #endif /* DROPBEAR_ECDSA */
+
+#if DROPBEAR_ED25519
+	if (type == DROPBEAR_SIGNKEY_ED25519) {
+		loadhostkey_helper("ed25519", (void**)&read_key->ed25519key, (void**)&svr_opts.hostkey->ed25519key, fatal_duplicate);
+	}
+#endif
+
 	sign_key_free(read_key);
 	TRACE(("leave loadhostkey"))
 }
@@ -527,7 +567,7 @@
 void load_all_hostkeys() {
 	int i;
 	int any_keys = 0;
-#ifdef DROPBEAR_ECDSA
+#if DROPBEAR_ECDSA
 	int loaded_any_ecdsa = 0;
 #endif
 
@@ -552,6 +592,9 @@
 #if DROPBEAR_ECDSA
 		loadhostkey(ECDSA_PRIV_FILENAME, 0);
 #endif
+#if DROPBEAR_ED25519
+		loadhostkey(ED25519_PRIV_FILENAME, 0);
+#endif
 	}
 
 #if DROPBEAR_RSA
@@ -615,6 +658,14 @@
 #endif
 #endif /* DROPBEAR_ECDSA */
 
+#if DROPBEAR_ED25519
+	if (!svr_opts.delay_hostkey && !svr_opts.hostkey->ed25519key) {
+		disablekey(DROPBEAR_SIGNKEY_ED25519);
+	} else {
+		any_keys = 1;
+	}
+#endif
+
 	if (!any_keys) {
 		dropbear_exit("No hostkeys available. 'dropbear -R' may be useful or run dropbearkey.");
 	}