/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is libguac-client-ssh.
 *
 * The Initial Developer of the Original Code is
 * Michael Jumper.
 * Portions created by the Initial Developer are Copyright (C) 2011
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef _GUAC_SSH_AGENT_H
#define _GUAC_SSH_AGENT_H

#include "ssh_key.h"

/**
 * Packet type of an agent identity request.
 */
#define SSH2_AGENT_REQUEST_IDENTITIES 0x0B

/**
 * Packet type of an agent identity response.
 */
#define SSH2_AGENT_IDENTITIES_ANSWER 0x0C

/**
 * Packet type of an agent sign request.
 */
#define SSH2_AGENT_SIGN_REQUEST 0x0D

/**
 * Packet type of an agent sign response.
 */
#define SSH2_AGENT_SIGN_RESPONSE 0x0E

/**
 * The comment to associate with public keys when listed.
 */
#define SSH_AGENT_COMMENT "Guacamole SSH Agent"

/**
 * The packet sent by the SSH agent when an operation is not supported.
 */
#define UNSUPPORTED "\x00\x00\x00\x0C\x05Unsupported"

/**
 * Data representing an SSH auth agent.
 */
typedef struct ssh_auth_agent {

    /**
     * The SSH channel being used for SSH agent protocol.
     */
    LIBSSH2_CHANNEL* channel;

    /**
     * The single private key to use for authentication.
     */
    ssh_key* identity;

    /**
     * Data read from the agent channel.
     */
    char buffer[4096];

    /**
     * The number of bytes of data currently stored in the buffer.
     */
    int buffer_length;

} ssh_auth_agent;

/**
 * Handler for an agent sign request.
 */
void ssh_auth_agent_sign(ssh_auth_agent* auth_agent,
        char* data, int data_length);

/**
 * Handler for an agent identity request.
 */
void ssh_auth_agent_list_identities(ssh_auth_agent* auth_agent);

/**
 * Generic handler for all packets received over the auth agent channel.
 */
void ssh_auth_agent_handle_packet(ssh_auth_agent* auth_agent,
        uint8_t type, char* data, int data_length);

/**
 * Reads and handles a single packet from the SSH agent channel associated
 * with the given ssh_auth_agent, returning the size of that packet, the size
 * of the partial packet read, or a negative value if an error occurs.
 */
int ssh_auth_agent_read(ssh_auth_agent* auth_agent);

/**
 * Libssh2 callback, invoked when the auth agent channel is opened.
 */
void ssh_auth_agent_callback(LIBSSH2_SESSION *session,
        LIBSSH2_CHANNEL *channel, void **abstract);

#endif