--- a/ssh.h	Sun May 17 23:58:31 2020 +0800
+++ b/ssh.h	Tue May 19 00:31:41 2020 +0800
@@ -32,6 +32,7 @@
 #define SSH_MSG_DEBUG                  4
 #define SSH_MSG_SERVICE_REQUEST        5
 #define SSH_MSG_SERVICE_ACCEPT         6
+#define SSH_MSG_EXT_INFO               7
 #define SSH_MSG_KEXINIT                20
 #define SSH_MSG_NEWKEYS                21
 #define SSH_MSG_KEXDH_INIT             30
@@ -94,6 +95,11 @@
 #define SSH_DISCONNECT_NO_MORE_AUTH_METHODS_AVAILABLE  14
 #define SSH_DISCONNECT_ILLEGAL_USER_NAME               15
 
+/* rfc8308 */
+#define SSH_EXT_INFO_S "ext-info-s"
+#define SSH_EXT_INFO_C "ext-info-c"
+#define SSH_SERVER_SIG_ALGS "server-sig-algs"
+
 /* service types */
 #define SSH_SERVICE_USERAUTH "ssh-userauth"
 #define SSH_SERVICE_USERAUTH_LEN 12