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/**
* \file libnetconf.h
* \author Radek Krejci <rkrejci@cesnet.cz>
* \author Michal Vasko <mvasko@cesnet.cz>
* \brief libnetconf2 main internal header.
*
* Copyright (c) 2015 CESNET, z.s.p.o.
*
* This source code is licensed under BSD 3-Clause License (the "License").
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://opensource.org/licenses/BSD-3-Clause
*/
#ifndef NC_LIBNETCONF_H_
#define NC_LIBNETCONF_H_
#include "config.h"
#include "netconf.h"
#include "log_p.h"
#include "session_p.h"
#include "messages_p.h"
/* Tests whether string is empty or non-empty. */
#define strisempty(str) ((str)[0] == '\0')
#define strnonempty(str) ((str)[0] != '\0')
/**
* @mainpage About
*
* libnetconf2 is a NETCONF library in C handling NETCONF authentication and all NETCONF
* RPC communication both server and client-side. NETCONF datastore and session management is not a part of this library,
* but it helps a lot with the sessions.
*
* @section about-features Main Features
*
* - Creating SSH (using libssh) or TLS (using OpenSSL) authenticated NETCONF sessions.
* - Creating NETCONF sessions with a pre-established transport protocol
* (using this mechanism the communication can be tunneled through sshd(8), for instance).
* - Creating NETCONF Call Home sessions.
* - Creating, sending, receiving, and replying to RPCs.
* - Receiving notifications.
*
* - \todo Creating and sending notifications.
*
* @section about-license License
*
* Copyright (c) 2015-2016 CESNET, z.s.p.o.
*
* (The BSD 3-Clause License)
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name of the Company nor the names of its contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*/
/**
* @page howto How To ...
*
* - @subpage howtoinit
* - @subpage howtoclient
* - @subpage howtoserver
* - @subpage howtoclientcomm
* - @subpage howtoservercomm
*/
/**
* @page howtoinit Init and Thread-safety Information
*
* Before working with the library, it must be initialized.
* Which init function to call depends on the libnetconf2 and libssh/OpenSSL
* (libssh and libcrypto) functions you plan to use in the application.
* If you use any libnetconf2 SSH or libssh functions, you need SSH. If you
* use any libnetconf2 TLS, libssl, or libcrypto functions, you need TLS.
* Based on this you select between nc_ssh_init(), nc_tls_init(), and
* nc_ssh_tls_init(). If you create only sessions with pre-established
* transport protocol (_inout functions), you do not need to call
* any init function at all.
*
* To prevent any reachable memory at the end of your application, there
* are complementary destroy functions available. If your application is
* multi-threaded, call the destroy functions in the last thread, after all
* the other threads have ended. In every other thread you should call
* nc_thread_destroy() just before it exits.
*
* If libnetconf2 is used in accordance with this information, there should
* not be memory leaks of any kind at program exit. For thread-safety details
* of libssh, libssl, and libcrypto please refer to the corresponding project
* documentation. libnetconf2 thread-safety information is below.
*
* Client is NOT thread-safe and there is no access control in the client
* functions at all. Server is MOSTLY thread-safe meaning you can set all the
* options simultaneously while listening for or accepting new sessions or
* polling the existing ones. It should even be safe to poll one session in
* several threads, but it is definitely discouraged. Generally, servers can
* use more threads without any problems as long as they keep their workflow sane
* (behavior such as freeing sessions only after no thread uses them or similar).
*
* Functions List
* --------------
*
* Available in both __nc_client.h__ and __nc_server.h__.
*
* - nc_ssh_init()
* - nc_ssh_destroy()
* - nc_tls_init()
* - nc_tls_destroy()
* - nc_ssh_tls_init()
* - nc_ssh_tls_destroy()
* - nc_thread_destroy()
*/
/**
* @page howtoclient Client sessions
*
* There are a lot of options for both an SSH and a TLS client. All of them
* have setters and getters so that there is no need to duplicate them in
* a client.
*
* SSH
* ===
*
* It is mostly required to set any SSH options and then simply connect to
* a NETCONF server. Optionally, some authetication callbacks can be set,
* which are particulary useful in automated clients (passwords cannot be
* asked a user) or simply if any additional information is retrieved some
* other way than from standard terminal input.
*
* Afterwards, there are 2 functions to use for a new server connection
* and an additional one for creating a new SSH channel on an existing
* NETCONF session. The libssh variant enables to customize the SSH session
* in every way the libssh allows, although that should not normally be needed.
*
* Functions List
* --------------
*
* Available in __nc_client.h__.
*
* - nc_client_ssh_set_auth_hostkey_check_clb()
* - nc_client_ssh_set_auth_password_clb()
* - nc_client_ssh_set_auth_interactive_clb()
* - nc_client_ssh_set_auth_privkey_passphrase_clb()
* - nc_client_ssh_add_keypair()
* - nc_client_ssh_del_keypair()
* - nc_client_ssh_get_keypair_count()
* - nc_client_ssh_get_keypair()
* - nc_client_ssh_set_auth_pref()
* - nc_client_ssh_get_auth_pref()
* - nc_client_ssh_set_username()
* - nc_client_ssh_get_username()
*
* - nc_connect_ssh()
* - nc_connect_libssh()
* - nc_connect_ssh_channel()
*
*
* TLS
* ===
*
* With TLS authentication, is is mandatory to set the client certificate
* with a private key and additional trusted certificates and revocation lists.
*
* Then there are again 2 functions for connecting, the libssl variant enables
* to customize the TLS session in every way the libssl allows.
*
* Functions List
* --------------
*
* Available in __nc_client.h__.
*
* - nc_client_tls_set_cert_key_paths()
* - nc_client_tls_get_cert_key_paths()
* - nc_client_tls_set_trusted_ca_paths()
* - nc_client_tls_get_trusted_ca_paths()
* - nc_client_tls_set_crl_paths()
* - nc_client_tls_get_crl_paths()
*
* - nc_connect_tls()
* - nc_connect_libssl()
*
*
* FD
* ==
*
* If you authenticated the connection using some tunneling software, you
* can pass its file descriptors to libnetconf2, which will continue to
* establish a full NETCONF session.
*
* Funtions List
* -------------
*
* Available in __nc_client.h__.
*
* - nc_connect_inout()
*
*
* Call Home
* =========
*
* Call Home needs the same options set as standard SSH or TLS and the functions
* reflect it exactly. However, to accept a connection, the client must first
* specify addresses and ports, which to listen on. Then connections can be
* accepted.
*
* Functions List
* --------------
*
* Available in __nc_client.h__.
*
* - nc_client_ssh_ch_set_auth_hostkey_check_clb()
* - nc_client_ssh_ch_set_auth_password_clb()
* - nc_client_ssh_ch_set_auth_interactive_clb()
* - nc_client_ssh_ch_set_auth_privkey_passphrase_clb()
* - nc_client_ssh_ch_add_bind_listen()
* - nc_client_ssh_ch_del_bind()
* - nc_client_ssh_ch_add_keypair()
* - nc_client_ssh_ch_del_keypair()
* - nc_client_ssh_ch_get_keypair_count()
* - nc_client_ssh_ch_get_keypair()
* - nc_client_ssh_ch_set_auth_pref()
* - nc_client_ssh_ch_get_auth_pref()
* - nc_client_ssh_ch_set_username()
* - nc_client_ssh_ch_get_username()
*
* - nc_client_tls_ch_add_bind_listen()
* - nc_client_tls_ch_del_bind()
* - nc_client_tls_ch_set_cert_key_paths()
* - nc_client_tls_ch_get_cert_key_paths()
* - nc_client_tls_ch_set_trusted_ca_paths()
* - nc_client_tls_ch_get_trusted_ca_paths()
* - nc_client_tls_ch_set_crl_paths()
* - nc_client_tls_ch_get_crl_paths()
*
* - nc_accept_callhome()
*
*
* Cleanup
* =======
*
* These options and the schema searchpath are stored in dynamically
* allocated memory. To free it, destroy the client, it cleans up all
* the options
*
* Functions List
* --------------
*
* Available in __nc_client.h__.
*
* - nc_client_destroy()
*/
/**
* @page howtoserver Server sessions
*
* Init
* ====
*
* Server has its own initialization function. With it, you set the
* server context, which determines what modules it supports and what
* capabilities to advertise. Few capabilities that cannot be learnt
* from the context are set with separate functions. So are several
* general options.
*
* Context does not only determine server modules, but its overall
* functionality as well. For every RPC the server should support,
* an nc_rpc_clb callback should be set on that node in the context.
* Server then calls these as appropriate [during poll](@ref howtoservercomm).
*
* Server options can be only set, there are no getters.
*
* Functions List
* --------------
*
* Available in __nc_server.h__.
*
* - nc_server_init()
* - nc_server_set_capab_withdefaults()
* - nc_server_set_capab_interleave()
* - nc_server_set_hello_timeout()
* - nc_server_set_idle_timeout()
*
*
* SSH
* ===
*
* To be able to accept SSH connections, an endpoint must be added
* and its options set.
*
* Functions List
* --------------
*
* Available in __nc_server.h__.
*
* - nc_server_ssh_add_endpt_listen()
* - nc_server_ssh_endpt_set_address()
* - nc_server_ssh_endpt_set_port()
* - nc_server_ssh_del_endpt()
*
* - nc_server_ssh_endpt_set_hostkey()
* - nc_server_ssh_endpt_set_banner()
* - nc_server_ssh_endpt_set_auth_methods()
* - nc_server_ssh_endpt_set_auth_attempts()
* - nc_server_ssh_endpt_set_auth_timeout()
* - nc_server_ssh_endpt_add_authkey()
* - nc_server_ssh_endpt_del_authkey()
*
*
* TLS
* ===
*
* TLS requires at least one endpoint too, but its options differ
* significantly from the SSH ones, especially in the cert-to-name
* options that TLS uses to derive usernames from client certificates.
*
* Functions List
* --------------
*
* Available in __nc_server.h__.
*
* - nc_server_tls_add_endpt_listen()
* - nc_server_tls_endpt_set_address()
* - nc_server_tls_endpt_set_port()
* - nc_server_tls_del_endpt()
*
* - nc_server_tls_endpt_set_cert()
* - nc_server_tls_endpt_set_cert_path()
* - nc_server_tls_endpt_set_key()
* - nc_server_tls_endpt_set_key_path()
* - nc_server_tls_endpt_add_trusted_cert()
* - nc_server_tls_endpt_add_trusted_cert_path()
* - nc_server_tls_endpt_set_trusted_ca_paths()
* - nc_server_tls_endpt_clear_certs()
* - nc_server_tls_endpt_set_crl_paths()
* - nc_server_tls_endpt_clear_crls()
* - nc_server_tls_endpt_add_ctn()
* - nc_server_tls_endpt_del_ctn()
*
* FD
* ==
*
* If you used a tunneling software, which does its own authentication,
* you can accept a NETCONF session on its file descriptors.
*
* Functions List
* --------------
*
* Available in __nc_server.h__.
*
* - nc_accept_inout()
*
*
* Call Home
* =========
*
* Call Home does not work with endpoints like standard sessions.
* The options must be reset manually after another Call Home session
* (with different options than the previous one) is to be established.
* Also, monitoring of these sessions is up to the application.
*
* Functions List
* --------------
*
* Available in __nc_server.h__.
*
* - nc_connect_callhome_ssh()
* - nc_connect_callhome_tls()
*
* - nc_server_ssh_ch_set_hostkey()
* - nc_server_ssh_ch_set_banner()
* - nc_server_ssh_ch_set_auth_methods()
* - nc_server_ssh_ch_set_auth_attempts()
* - nc_server_ssh_ch_set_auth_timeout()
* - nc_server_ssh_ch_add_authkey()
* - nc_server_ssh_ch_del_authkey()
* - nc_server_ssh_ch_clear_opts()
*
* - nc_server_tls_ch_set_cert()
* - nc_server_tls_ch_set_cert_path()
* - nc_server_tls_ch_set_key()
* - nc_server_tls_ch_set_key_path()
* - nc_server_tls_ch_add_trusted_cert()
* - nc_server_tls_ch_add_trusted_cert_path()
* - nc_server_tls_ch_set_trusted_ca_paths()
* - nc_server_tls_ch_clear_certs()
* - nc_server_tls_ch_set_crl_paths()
* - nc_server_tls_ch_clear_crls()
* - nc_server_tls_ch_add_ctn()
* - nc_server_tls_ch_del_ctn()
* - nc_server_tls_ch_clear_opts()
*
*
* Connecting And Cleanup
* ======================
*
* When accepting connections, all the endpoints are examined
* and the first with a pending connection is used. To remove all
* the endpoints and free any used dynamic memory, destroy the server.
*
* Functions List
* --------------
*
* Available in __nc_server.h__.
*
* - nc_accept()
*
* - nc_server_destroy()
*/
/**
* @page howtoclientcomm Client communication
*
* To send RPCs on a session, you simply create an RPC, send it,
* and then wait for a reply. If you are subscribed, there are 2 ways
* of receiving notifications. Either you wait for them the same way
* as for standard replies or you create a dispatcher that asynchronously
* (in a separate thread) reads notifications and passes them to your
* callback.
*
* Functions List
* --------------
*
* Available in __nc_client.h__.
*
* - nc_rpc_generic()
* - nc_rpc_generic_xml()
* - nc_rpc_getconfig()
* - nc_rpc_edit()
* - nc_rpc_copy()
* - nc_rpc_delete()
* - nc_rpc_lock()
* - nc_rpc_unlock()
* - nc_rpc_get()
* - nc_rpc_kill()
* - nc_rpc_commit()
* - nc_rpc_discard()
* - nc_rpc_cancel()
* - nc_rpc_validate()
* - nc_rpc_getschema()
* - nc_rpc_subscribe()
*
* - nc_send_rpc()
* - nc_recv_reply()
* - nc_recv_notif()
* - nc_recv_notif_dispatch()
*/
/**
* @page howtoservercomm Server communication
*
* Once at least one session is established, an nc_pollsession structure
* should be created, filled with the session and polled. Based on
* the return value from the poll further actions can be taken. More
* sessions can be polled at the same time. Any requests received on
* the sessions are [handled internally](@ref howtoserver).
*
* Functions List
* --------------
*
* Available in __nc_client.h__.
*
* - nc_ps_new()
* - nc_ps_add_session()
* - nc_ps_del_session()
* - nc_ps_free()
*
* - nc_ps_poll()
* - nc_ps_clear()
* - nc_ps_accept_ssh_channel()
*/
#endif /* NC_LIBNETCONF_H_ */