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/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#define OPENVPN_PLUGIN_VERSION 2
/*
* Plug-in types. These types correspond to the set of script callbacks
* supported by OpenVPN.
*
* This is the general call sequence to expect when running in server mode:
*
* Initial Server Startup:
*
* FUNC: openvpn_plugin_open_v1
* FUNC: openvpn_plugin_client_constructor_v1 (this is the top-level "generic"
* client template)
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_UP
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_ROUTE_UP
*
* New Client Connection:
*
* FUNC: openvpn_plugin_client_constructor_v1
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_ENABLE_PF
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_TLS_VERIFY (called once for every cert
* in the server chain)
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_TLS_FINAL
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_IPCHANGE
*
* [If OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY returned OPENVPN_PLUGIN_FUNC_DEFERRED,
* we don't proceed until authentication is verified via auth_control_file]
*
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_CLIENT_CONNECT_V2
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_LEARN_ADDRESS
*
* [Client session ensues]
*
* For each "TLS soft reset", according to reneg-sec option (or similar):
*
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_ENABLE_PF
*
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_TLS_VERIFY (called once for every cert
* in the server chain)
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_TLS_FINAL
*
* [If OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY returned OPENVPN_PLUGIN_FUNC_DEFERRED,
* we expect that authentication is verified via auth_control_file within
* the number of seconds defined by the "hand-window" option. Data channel traffic
* will continue to flow uninterrupted during this period.]
*
* [Client session continues]
*
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_CLIENT_DISCONNECT
* FUNC: openvpn_plugin_client_destructor_v1
*
* [ some time may pass ]
*
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_LEARN_ADDRESS (this coincides with a
* lazy free of initial
* learned addr object)
* Server Shutdown:
*
* FUNC: openvpn_plugin_func_v1 OPENVPN_PLUGIN_DOWN
* FUNC: openvpn_plugin_client_destructor_v1 (top-level "generic" client)
* FUNC: openvpn_plugin_close_v1
*/
#define OPENVPN_PLUGIN_UP 0
#define OPENVPN_PLUGIN_DOWN 1
#define OPENVPN_PLUGIN_ROUTE_UP 2
#define OPENVPN_PLUGIN_IPCHANGE 3
#define OPENVPN_PLUGIN_TLS_VERIFY 4
#define OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY 5
#define OPENVPN_PLUGIN_CLIENT_CONNECT 6
#define OPENVPN_PLUGIN_CLIENT_DISCONNECT 7
#define OPENVPN_PLUGIN_LEARN_ADDRESS 8
#define OPENVPN_PLUGIN_CLIENT_CONNECT_V2 9
#define OPENVPN_PLUGIN_TLS_FINAL 10
#define OPENVPN_PLUGIN_ENABLE_PF 11
#define OPENVPN_PLUGIN_N 12
/*
* Build a mask out of a set of plug-in types.
*/
#define OPENVPN_PLUGIN_MASK(x) (1<<(x))
/*
* A pointer to a plugin-defined object which contains
* the object state.
*/
typedef void *openvpn_plugin_handle_t;
/*
* Return value for openvpn_plugin_func_v1 function
*/
#define OPENVPN_PLUGIN_FUNC_SUCCESS 0
#define OPENVPN_PLUGIN_FUNC_ERROR 1
#define OPENVPN_PLUGIN_FUNC_DEFERRED 2
/*
* For Windows (needs to be modified for MSVC)
*/
#if defined(__MINGW32_VERSION) && !defined(OPENVPN_PLUGIN_H)
# define OPENVPN_EXPORT __declspec(dllexport)
#else
# define OPENVPN_EXPORT
#endif
/*
* If OPENVPN_PLUGIN_H is defined, we know that we are being
* included in an OpenVPN compile, rather than a plugin compile.
*/
#ifdef OPENVPN_PLUGIN_H
/*
* We are compiling OpenVPN.
*/
#define OPENVPN_PLUGIN_DEF typedef
#define OPENVPN_PLUGIN_FUNC(name) (*name)
#else
/*
* We are compiling plugin.
*/
#define OPENVPN_PLUGIN_DEF OPENVPN_EXPORT
#define OPENVPN_PLUGIN_FUNC(name) name
#endif
/*
* Used by openvpn_plugin_func to return structured
* data. The plugin should allocate all structure
* instances, name strings, and value strings with
* malloc, since OpenVPN will assume that it
* can free the list by calling free() over the same.
*/
struct openvpn_plugin_string_list
{
struct openvpn_plugin_string_list *next;
char *name;
char *value;
};
/*
* Multiple plugin modules can be cascaded, and modules can be
* used in tandem with scripts. The order of operation is that
* the module func() functions are called in the order that
* the modules were specified in the config file. If a script
* was specified as well, it will be called last. If the
* return code of the module/script controls an authentication
* function (such as tls-verify or auth-user-pass-verify), then
* every module and script must return success (0) in order for
* the connection to be authenticated.
*
* Notes:
*
* Plugins which use a privilege-separation model (by forking in
* their initialization function before the main OpenVPN process
* downgrades root privileges and/or executes a chroot) must
* daemonize after a fork if the "daemon" environmental variable is
* set. In addition, if the "daemon_log_redirect" variable is set,
* the plugin should preserve stdout/stderr across the daemon()
* syscall. See the daemonize() function in plugin/auth-pam/auth-pam.c
* for an example.
*/
/*
* Prototypes for functions which OpenVPN plug-ins must define.
*/
/*
* FUNCTION: openvpn_plugin_open_v2
*
* REQUIRED: YES
*
* Called on initial plug-in load. OpenVPN will preserve plug-in state
* across SIGUSR1 restarts but not across SIGHUP restarts. A SIGHUP reset
* will cause the plugin to be closed and reopened.
*
* ARGUMENTS
*
* *type_mask : Set by OpenVPN to the logical OR of all script
* types which this version of OpenVPN supports. The plug-in
* should set this value to the logical OR of all script types
* which the plug-in wants to intercept. For example, if the
* script wants to intercept the client-connect and
* client-disconnect script types:
*
* *type_mask = OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_CLIENT_CONNECT)
* | OPENVPN_PLUGIN_MASK(OPENVPN_PLUGIN_CLIENT_DISCONNECT)
*
* argv : a NULL-terminated array of options provided to the OpenVPN
* "plug-in" directive. argv[0] is the dynamic library pathname.
*
* envp : a NULL-terminated array of OpenVPN-set environmental
* variables in "name=value" format. Note that for security reasons,
* these variables are not actually written to the "official"
* environmental variable store of the process.
*
* return_list : used to return data back to OpenVPN.
*
* RETURN VALUE
*
* An openvpn_plugin_handle_t value on success, NULL on failure
*/
OPENVPN_PLUGIN_DEF openvpn_plugin_handle_t OPENVPN_PLUGIN_FUNC(openvpn_plugin_open_v2)
(unsigned int *type_mask,
const char *argv[],
const char *envp[],
struct openvpn_plugin_string_list **return_list);
/*
* FUNCTION: openvpn_plugin_func_v2
*
* Called to perform the work of a given script type.
*
* REQUIRED: YES
*
* ARGUMENTS
*
* handle : the openvpn_plugin_handle_t value which was returned by
* openvpn_plugin_open.
*
* type : one of the PLUGIN_x types
*
* argv : a NULL-terminated array of "command line" options which
* would normally be passed to the script. argv[0] is the dynamic
* library pathname.
*
* envp : a NULL-terminated array of OpenVPN-set environmental
* variables in "name=value" format. Note that for security reasons,
* these variables are not actually written to the "official"
* environmental variable store of the process.
*
* per_client_context : the per-client context pointer which was returned by
* openvpn_plugin_client_constructor_v1, if defined.
*
* return_list : used to return data back to OpenVPN.
*
* RETURN VALUE
*
* OPENVPN_PLUGIN_FUNC_SUCCESS on success, OPENVPN_PLUGIN_FUNC_ERROR on failure
*
* In addition, OPENVPN_PLUGIN_FUNC_DEFERRED may be returned by
* OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY. This enables asynchronous
* authentication where the plugin (or one of its agents) may indicate
* authentication success/failure some number of seconds after the return
* of the OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY handler by writing a single
* char to the file named by auth_control_file in the environmental variable
* list (envp).
*
* first char of auth_control_file:
* '0' -- indicates auth failure
* '1' -- indicates auth success
*
* OpenVPN will delete the auth_control_file after it goes out of scope.
*
* If an OPENVPN_PLUGIN_ENABLE_PF handler is defined and returns success
* for a particular client instance, packet filtering will be enabled for that
* instance. OpenVPN will then attempt to read the packet filter configuration
* from the temporary file named by the environmental variable pf_file. This
* file may be generated asynchronously and may be dynamically updated during the
* client session, however the client will be blocked from sending or receiving
* VPN tunnel packets until the packet filter file has been generated. OpenVPN
* will periodically test the packet filter file over the life of the client
* instance and reload when modified. OpenVPN will delete the packet filter file
* when the client instance goes out of scope.
*
* Packet filter file grammar:
*
* [CLIENTS DROP|ACCEPT]
* {+|-}common_name1
* {+|-}common_name2
* . . .
* [SUBNETS DROP|ACCEPT]
* {+|-}subnet1
* {+|-}subnet2
* . . .
* [END]
*
* Subnet: IP-ADDRESS | IP-ADDRESS/NUM_NETWORK_BITS
*
* CLIENTS refers to the set of clients (by their common-name) which
* this instance is allowed ('+') to connect to, or is excluded ('-')
* from connecting to. Note that in the case of client-to-client
* connections, such communication must be allowed by the packet filter
* configuration files of both clients.
*
* SUBNETS refers to IP addresses or IP address subnets which this
* instance may connect to ('+') or is excluded ('-') from connecting
* to.
*
* DROP or ACCEPT defines default policy when there is no explicit match
* for a common-name or subnet. The [END] tag must exist. A special
* purpose tag called [KILL] will immediately kill the client instance.
* A given client or subnet rule applies to both incoming and outgoing
* packets.
*
* See plugin/defer/simple.c for an example on using asynchronous
* authentication and client-specific packet filtering.
*/
OPENVPN_PLUGIN_DEF int OPENVPN_PLUGIN_FUNC(openvpn_plugin_func_v2)
(openvpn_plugin_handle_t handle,
const int type,
const char *argv[],
const char *envp[],
void *per_client_context,
struct openvpn_plugin_string_list **return_list);
/*
* FUNCTION: openvpn_plugin_close_v1
*
* REQUIRED: YES
*
* ARGUMENTS
*
* handle : the openvpn_plugin_handle_t value which was returned by
* openvpn_plugin_open.
*
* Called immediately prior to plug-in unload.
*/
OPENVPN_PLUGIN_DEF void OPENVPN_PLUGIN_FUNC(openvpn_plugin_close_v1)
(openvpn_plugin_handle_t handle);
/*
* FUNCTION: openvpn_plugin_abort_v1
*
* REQUIRED: NO
*
* ARGUMENTS
*
* handle : the openvpn_plugin_handle_t value which was returned by
* openvpn_plugin_open.
*
* Called when OpenVPN is in the process of aborting due to a fatal error.
* Will only be called on an open context returned by a prior successful
* openvpn_plugin_open callback.
*/
OPENVPN_PLUGIN_DEF void OPENVPN_PLUGIN_FUNC(openvpn_plugin_abort_v1)
(openvpn_plugin_handle_t handle);
/*
* FUNCTION: openvpn_plugin_client_constructor_v1
*
* Called to allocate a per-client memory region, which
* is then passed to the openvpn_plugin_func_v2 function.
* This function is called every time the OpenVPN server
* constructs a client instance object, which normally
* occurs when a session-initiating packet is received
* by a new client, even before the client has authenticated.
*
* This function should allocate the private memory needed
* by the plugin to track individual OpenVPN clients, and
* return a void * to this memory region.
*
* REQUIRED: NO
*
* ARGUMENTS
*
* handle : the openvpn_plugin_handle_t value which was returned by
* openvpn_plugin_open.
*
* RETURN VALUE
*
* void * pointer to plugin's private per-client memory region, or NULL
* if no memory region is required.
*/
OPENVPN_PLUGIN_DEF void * OPENVPN_PLUGIN_FUNC(openvpn_plugin_client_constructor_v1)
(openvpn_plugin_handle_t handle);
/*
* FUNCTION: openvpn_plugin_client_destructor_v1
*
* This function is called on client instance object destruction.
*
* REQUIRED: NO
*
* ARGUMENTS
*
* handle : the openvpn_plugin_handle_t value which was returned by
* openvpn_plugin_open.
*
* per_client_context : the per-client context pointer which was returned by
* openvpn_plugin_client_constructor_v1, if defined.
*/
OPENVPN_PLUGIN_DEF void OPENVPN_PLUGIN_FUNC(openvpn_plugin_client_destructor_v1)
(openvpn_plugin_handle_t handle, void *per_client_context);
/*
* FUNCTION: openvpn_plugin_select_initialization_point_v1
*
* Several different points exist in OpenVPN's initialization sequence where
* the openvpn_plugin_open function can be called. While the default is
* OPENVPN_PLUGIN_INIT_PRE_DAEMON, this function can be used to select a
* different initialization point. For example, if your plugin needs to
* return configuration parameters to OpenVPN, use
* OPENVPN_PLUGIN_INIT_PRE_CONFIG_PARSE.
*
* REQUIRED: NO
*
* RETURN VALUE:
*
* An OPENVPN_PLUGIN_INIT_x value.
*/
#define OPENVPN_PLUGIN_INIT_PRE_CONFIG_PARSE 1
#define OPENVPN_PLUGIN_INIT_PRE_DAEMON 2 /* default */
#define OPENVPN_PLUGIN_INIT_POST_DAEMON 3
#define OPENVPN_PLUGIN_INIT_POST_UID_CHANGE 4
OPENVPN_PLUGIN_DEF int OPENVPN_PLUGIN_FUNC(openvpn_plugin_select_initialization_point_v1)
(void);
/*
* FUNCTION: openvpn_plugin_min_version_required_v1
*
* This function is called by OpenVPN to query the minimum
plugin interface version number required by the plugin.
*
* REQUIRED: NO
*
* RETURN VALUE
*
* The minimum OpenVPN plugin interface version number necessary to support
* this plugin.
*/
OPENVPN_PLUGIN_DEF int OPENVPN_PLUGIN_FUNC(openvpn_plugin_min_version_required_v1)
(void);
/*
* Deprecated functions which are still supported for backward compatibility.
*/
OPENVPN_PLUGIN_DEF openvpn_plugin_handle_t OPENVPN_PLUGIN_FUNC(openvpn_plugin_open_v1)
(unsigned int *type_mask,
const char *argv[],
const char *envp[]);
OPENVPN_PLUGIN_DEF int OPENVPN_PLUGIN_FUNC(openvpn_plugin_func_v1)
(openvpn_plugin_handle_t handle, const int type, const char *argv[], const char *envp[]);