--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/pubkeyapi.h	Wed May 15 09:43:57 2019 -0400
@@ -0,0 +1,151 @@
+/*
+ * Dropbear - a SSH2 server
+ * 
+ * Copyright (c) 2002,2003 Matt Johnston
+ * All rights reserved.
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE. */
+#ifndef DROPBEAR_PUBKEY_H
+#define DROPBEAR_PUBKEY_H
+
+
+/* External Public Key API (EPKA) Plug-in Interface
+ *
+ * See:
+ *      https://github.com/fabriziobertocci/dropbear-epka
+ * for additional information and examples about this API
+ *
+ */
+
+struct EPKAInstance;
+struct EPKASession;
+
+/* API VERSION INFORMATION - 
+ * Dropbear will:
+ * - Reject any plugin with a major version mismatch
+ * - Load and print a warning if the plugin's minor version is HIGHER than
+ *   dropbear's minor version (assumes properties are added at the end of
+ *   EPKAInstance or EPKASession). This is a case of plugin newer than dropbear. 
+ * - Reject if the plugin minor version is SMALLER than dropbear one (case
+ *   of plugin older than dropbear).
+ * - Load (with no warnings) if version match.
+ */
+#define DROPBEAR_EPKA_VERSION_MAJOR     1
+#define DROPBEAR_EPKA_VERSION_MINOR     0
+
+
+/* Creates an instance of the plugin.
+ *
+ * This is the main entry point of the plug-in and should be IMMUTABLE across
+ * different API versions. Dropbear will check the version number
+ * returned in the api_version to match the version it understands and reject
+ * any plugin for which API major version does not match.
+ *
+ * If the version MINOR is different, dropbear will allow the plugin to run 
+ * only if: plugin_MINOR > dropbear_MINOR
+ *
+ * If plugin_MINOR < dropbeart_MINOR or if the MAJOR version is different
+ * dropbear will reject the plugin and terminate the execution.
+ *
+ * addrstring is the IP address of the client.
+ *
+ * Returns NULL in case of failure, otherwise a void * of the instance that need
+ * to be passed to all the subsequent call to the plugin
+ */
+typedef struct EPKAInstance *(* PubkeyExtPlugin_newFn)(int verbose, 
+        const char *options,
+        const char *addrstring);
+#define DROPBEAR_PUBKEY_PLUGIN_FNNAME_NEW               "plugin_new"
+
+
+/* Validate a client through public key authentication
+ *
+ * If session has not been already created, creates it and store it 
+ * in *sessionInOut.
+ * If session is a non-NULL, it will reuse it.
+ *
+ * Returns DROPBEAR_SUCCESS (0) if success or DROPBEAR_FAILURE (-1) if
+ * authentication fails
+ */
+typedef int (* PubkeyExtPlugin_checkPubKeyFn)(struct EPKAInstance *pluginInstance,
+        struct EPKASession **sessionInOut,
+        const char* algo, 
+        unsigned int algolen,
+        const unsigned char* keyblob, 
+        unsigned int keybloblen,
+        const char *username);
+
+/* Notify the plugin that auth completed (after signature verification)
+ */
+typedef void (* PubkeyExtPlugin_authSuccessFn)(struct EPKASession *session);
+
+/* Deletes a session
+ * TODO: Add a reason why the session is terminated. See svr_dropbear_exit (in svr-session.c)
+ */
+typedef void (* PubkeyExtPlugin_sessionDeleteFn)(struct EPKASession *session);
+
+/* Deletes the plugin instance */
+typedef void (* PubkeyExtPlugin_deleteFn)(struct EPKAInstance *pluginInstance);
+
+
+/* The EPKAInstance object - A simple container of the pointer to the functions used
+ * by Dropbear.
+ *
+ * A plug-in can extend it to add its own properties
+ *
+ * The instance is created from the call to the plugin_new() function of the 
+ * shared library.
+ * The delete_plugin function should delete the object.
+ */
+struct EPKAInstance {
+    int                             api_version[2];         /* 0=Major, 1=Minor */
+
+    PubkeyExtPlugin_checkPubKeyFn   checkpubkey;            /* mandatory */
+    PubkeyExtPlugin_authSuccessFn   auth_success;           /* optional */
+    PubkeyExtPlugin_sessionDeleteFn delete_session;         /* mandatory */
+    PubkeyExtPlugin_deleteFn        delete_plugin;          /* mandatory */
+};
+
+/*****************************************************************************
+ * SESSION
+ ****************************************************************************/
+/* Returns the options from the session. 
+ * The returned buffer will be destroyed when the session is deleted.
+ * Option buffer string NULL-terminated
+ */
+typedef char * (* PubkeyExtPlugin_getOptionsFn)(struct EPKASession *session);
+
+
+/* An SSH Session. Created during pre-auth and reused during the authentication.
+ * The plug-in should delete this object (or any object extending it) from 
+ * the delete_session() function.
+ *
+ * Extend it to cache user and authentication information that can be
+ * reused between pre-auth and auth (and to store whatever session-specific
+ * variable you need to keep).
+ *
+ * Store any optional auth options in the auth_options property of the session.
+ */
+struct EPKASession {
+    struct EPKAInstance *  plugin_instance;
+
+    PubkeyExtPlugin_getOptionsFn   get_options;
+};
+
+#endif