xref: /illumos-gate/usr/src/lib/libsldap/common/ns_connmgmt.h (revision 695ef821379e863d33c30fb148f4ecf87038b246)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  *
25  * Copyright 2017 Nexenta Systems, Inc.  All rights reserved.
26  */
27 
28 #ifndef	_NS_CONNMGMT_H
29 #define	_NS_CONNMGMT_H
30 
31 #ifdef __cplusplus
32 extern "C" {
33 #endif
34 
35 #include <thread.h>
36 #include "ns_sldap.h"
37 #include "ns_internal.h"
38 #include "ns_cache_door.h"
39 
40 struct ns_conn_user; /* connection user, forward definition */
41 struct ns_conn_mt;   /* multi-threaded (MT) connection, forward definition */
42 struct ns_conn_mgmt; /* connection management, forward definition */
43 
44 #define	NS_CONN_MT_USER_NO_MAX	-1
45 #define	NS_CONN_MT_USER_MAX	NS_CONN_MT_USER_NO_MAX
46 #define	NS_LIST_TRY_MAX		3
47 
48 /*
49  * Structure for handling the waiter of a pending multi-threaded (MT) connection
50  */
51 typedef struct ns_conn_waiter {
52 	cond_t			waitcv;
53 	uint8_t			signaled;
54 	struct ns_conn_user	*key;
55 	struct ns_conn_waiter	*next, *prev;
56 } ns_conn_waiter_t;
57 
58 /*
59  * type of a connection user
60  */
61 typedef enum {
62 	NS_CONN_USER_SEARCH	= 1,
63 	NS_CONN_USER_WRITE	= 2,
64 	NS_CONN_USER_AUTH	= 3,
65 	NS_CONN_USER_GETENT	= 4
66 } ns_conn_user_type_t;
67 
68 /*
69  * state of a connection user
70  */
71 typedef enum {
72 	NS_CONN_USER_UNINITED		= 0,
73 	NS_CONN_USER_ALLOCATED		= 1,
74 	NS_CONN_USER_FINDING		= 2, /* looking for an MT connection */
75 	NS_CONN_USER_WAITING		= 3, /* waiting for an MT connection */
76 	NS_CONN_USER_WOKEUP		= 4,
77 	NS_CONN_USER_CONNECT_ERROR	= 5,
78 	NS_CONN_USER_CONNECTED  	= 6,
79 	NS_CONN_USER_DISCONNECTED	= 7,
80 	NS_CONN_USER_FREED		= 8
81 } ns_conn_user_state_t;
82 
83 /*
84  * A connection user represents a request processed by libsldap. It
85  * usually is a thread using the same connection from start to end.
86  * Different connection users of the same type can share the same
87  * connection opened for that type. But search and getent users can
88  * share the same connection opened for either search or getent. AUTH
89  * connection are not shareable.
90  *
91  * A getent user may have a longer lifespan and live outside of libsldap.
92  * This is because the associated search cookie is passed back to the caller
93  * via the firstEntry call and used in the subsequent nextEntry or endEntry
94  * calls. Even though the firstEntry and the nextEntry/endEntry calls may
95  * be running in a different thread, the connection being used will be the
96  * same. It is the one assigend during the firstEntry call.
97  */
98 struct ns_conn_user {
99 	ns_conn_user_type_t	type; /* search, write, auth, getent, ... */
100 	ns_conn_user_state_t	state;
101 	thread_t		tid;   /* id of the thread starts the request */
102 	struct ns_conn_user	*next; /* next conn_user in the linked list */
103 	struct ns_conn_mt	*conn_mt; /* the MT connection being used */
104 	struct ns_conn_mgmt	*conn_mgmt; /* ref counted conn management */
105 	void			*userinfo; /* private data of the request */
106 	ns_ldap_return_code	ns_rc; /* error return code */
107 	ns_ldap_error_t		*ns_error; /* error info */
108 	boolean_t		referral; /* using a referred server ? */
109 	boolean_t		retry; /* retry the request on certain error? */
110 	boolean_t		keep_conn; /* keep the conn for reuse ? */
111 	boolean_t		use_mt_conn; /* using/used an MT connection ? */
112 	boolean_t		bad_mt_conn; /* MT connection is not usable ? */
113 };
114 
115 /*
116  * state of an MT connection
117  */
118 typedef enum {
119 	NS_CONN_MT_UNINITED		= 0,
120 	NS_CONN_MT_CONNECTING		= 1,
121 	NS_CONN_MT_CONNECT_ERROR	= 2,
122 	NS_CONN_MT_CONNECTED		= 3,
123 	NS_CONN_MT_CLOSING		= 4
124 } ns_conn_mt_state_t;
125 
126 /*
127  * An ns_conn_mt (or MT connection) represents an ldap connection
128  * that can be shared among multiple threads. It also represents
129  * the set of connection users using the ldap connection. It contains
130  * a pointer to the Connection structure that has the physical info
131  * of the connection (server name, address, ldap handle, etc). It
132  * also contains a linked list of all the conn_user using the ldap
133  * connection. The connection users can wait on an MT connection
134  * to become available or be told to abort and clean up when one of
135  * the connection user detects an error and knows that the connection
136  * is no longer usable. The error info is then saved in the structure
137  * for other users to consume.
138  *
139  * An MT connection is meant to be shared concurrently and persistent.
140  * Even when there's no current user, it will be kept by the connection
141  * management, waiting for the next user. It will be closed when
142  * a connection error is detected, when a better server should be
143  * used, when the Native LDAP configuration change, or when the libsldap
144  * is being unloaded.
145  */
146 typedef struct ns_conn_mt {
147 	mutex_t			lock;
148 	ns_conn_mt_state_t	state;
149 	pid_t			pid; /* process creates the connection */
150 	thread_t		tid; /* thread creates the connection */
151 	struct ns_conn_mt	*next; /* next conn_mt in the linked list */
152 	ns_conn_user_t		*cu_head; /* head of conn_user linked list */
153 	ns_conn_user_t		*cu_tail; /* tail of conn_user linked list */
154 	struct ns_conn_mgmt	*conn_mgmt; /* ref counted conn management */
155 	ns_conn_waiter_t	waiter; /* first of the connection waiters */
156 	uint_t			cu_cnt; /* number of the using conn_user */
157 	int32_t			cu_max; /* max. allowed number of conn_user */
158 	uint_t			waiter_cnt; /* number of waiters */
159 	ns_conn_user_type_t	opened_for; /* type of conn_user opened for */
160 	Connection		*conn; /* name, IP address, ldap handle, etc */
161 	time_t			create_time; /* time when connection created */
162 	time_t			access_time; /* time when last used */
163 	ns_ldap_return_code	ns_rc; /* saved error code */
164 	ns_ldap_error_t		*ns_error; /* saved error info */
165 	boolean_t		close_when_nouser;  /* close connection when */
166 						    /* last user is done ? */
167 	boolean_t		detached; /* no longer in connection pool? */
168 	boolean_t		referral; /* using a referred server ? */
169 } ns_conn_mt_t;
170 
171 /*
172  * state of a connection management
173  * (a connection pool sharing the same native LDAP configuration)
174  */
175 typedef enum {
176 	NS_CONN_MGMT_UNINITED	= 0,
177 	NS_CONN_MGMT_INACTIVE	= 1, /* conn sharing not yet requested */
178 	NS_CONN_MGMT_ACTIVE	= 2, /* connection sharing required/requested */
179 	NS_CONN_MGMT_DETACHED	= 3  /* on the way down, no new user allowed */
180 } ns_conn_mgmt_state_t;
181 
182 /*
183  * An ns_conn_mgmt (or connection management) represents the set of MT
184  * connections using the same native LDAP configuration. It is a connection
185  * pool that can adjust the MT connection status and usage based on the
186  * change notifications it receives from the ldap_cachemgr daemon, OR When
187  * the change is detected at config refresh time. When a server status
188  * change (up or down) notification is received or detected, it will
189  * close the MT connections using the server. Or mark them as to-be-closed
190  * and close them when all users are done using them. When a config change
191  * notice is received, it will detach itself and allow a new ns_conn_mgmt be
192  * created for the new configuration. The old config would still be used
193  * by the detached ns_conn_mgmt. Both will be destroyed when all existing
194  * conn_user are done. Any conn_user and MT connection created after the
195  * configuration switch will use the new configuration.
196  *
197  * Note that there's always just one current ns_conn_mgmt. Its usage is
198  * reference counted. Any new conn_user or MT connection referencing
199  * the ns_conn_mgmt adds 1 to the count, any release of the ns_conn_mgmt
200  * decrement the count by 1. The ns_conn_mgmt can not be freed until
201  * the reference count becomes zero.
202  *
203  * Each ns_conn_mgmt references a native LDAP configuration. The config
204  * component of this library always maintains a global configuration. It is
205  * referred to as the current global config. The current ns_conn_mgmt
206  * uses that global config. When an ns_conn_mgmt is detached, or not
207  * longer active/current, the config it uses is no longer the current global
208  * one, which is referred as the per connection management config. When
209  * the ns_conn_mgmt is freed, the config will also be destroyed.
210  */
211 
212 typedef struct ns_conn_mgmt {
213 	mutex_t		lock;
214 	ns_conn_mgmt_state_t state;
215 	pid_t		pid; /* process creates the conn_mgmt */
216 	thread_t	procchg_tid; /* id of the change monitor thread */
217 	ns_conn_mt_t	*cm_head; /* head of the conn_mt linked list */
218 	ns_conn_mt_t	*cm_tail; /* tail of the conn_mt linked list */
219 	mutex_t		cfg_lock; /* lock serializes access to config */
220 	ldap_get_chg_cookie_t cfg_cookie; /* used to detect if config changes */
221 	ns_config_t	*config; /* the native LDAP config being used */
222 	char		**pservers; /* preferred servers defined in config */
223 	uint_t		cm_cnt;  /* number of MT connection in the pool */
224 	uint_t		ref_cnt; /* number of reference by conn_MT/conn_user */
225 	boolean_t	is_nscd; /* running in a nscd ? */
226 	boolean_t	is_peruser_nscd; /* running in a per-user nscd ? */
227 	boolean_t	ldap_mt; /* libldap supports multi-threaded client ? */
228 	boolean_t	do_mt_conn;	/* need and able to do MT conn ? */
229 	boolean_t	shutting_down;  /* on the way down ? */
230 	boolean_t	cfg_reloaded;   /* config is not current ? */
231 	boolean_t	procchg_started; /* change monitor thread started ? */
232 	boolean_t	procchg_door_call; /* in door call and waiting ? */
233 	boolean_t	pservers_loaded; /* pservers array is set ? */
234 } ns_conn_mgmt_t;
235 
236 /*
237  * For a connection management and the conn_mt connections it manages, it is
238  * very helpful to know exactly when the Native LDAP configuration changes
239  * and when the status of the configured servers change. If the config
240  * changes, new connection management will be created. If servers go up
241  * or down, conn_mt connections being used need to be dropped or switched.
242  * For processes other than the main nscd, the changes has to be detected
243  * in a less efficient way by libsldap. For the main nscd (not including
244  * peruser nscd), the connection management which has active conn_mt
245  * connections can rely on the ldap_cachemgr daemon to report if there's any
246  * change in servers' status or if the native LDAP configuration has changed.
247  *
248  * The mechanism for reporting of the changes is a door call sent from
249  * libsldap to ldap_cachemgr. The call will not be returned until changes
250  * detected by ldap_cachemgr. When the change info is passed back to
251  * libsldap, the change monitor thread will wake up from the door call
252  * and process the notification. For servers went from up to down, the
253  * associated MT connections will be closed, and then all conn_users'
254  * state will be marked as closing. When a conn_user notices it, the
255  * operations represented by that conn_user will be ended with error
256  * info. When a more preferred server is up, MT connections using
257  * less preferred servers will be marked as closed-when-all-user-done,
258  * so that new connection will be opened and using the preferred server.
259  * A configuration change causes the current connection management and
260  * the configuration it uses to become detached but continually being
261  * used by the old MT connections. Any new MT connection opened will
262  * be put in a new connection management and uses the new configuration
263  * immediately.
264  */
265 typedef enum {
266 	NS_SERVER_UP	= 1,
267 	NS_SERVER_DOWN	= 2
268 } ns_server_status_t;
269 
270 typedef struct ns_server_status_change {
271 	int			num_server;
272 	boolean_t		config_changed;
273 	ns_server_status_t	*changes;	/* array of status change */
274 	char			**servers;	/* array of server */
275 } ns_server_status_change_t;
276 
277 /*
278  * connection management functions
279  */
280 ns_conn_mgmt_t *__s_api_conn_mgmt_init();
281 int __s_api_setup_mt_ld(LDAP *ld);
282 int __s_api_check_mtckey();
283 void __s_api_use_prev_conn_mgmt(int, ns_config_t *);
284 ns_conn_user_t *__s_api_conn_user_init(int, void *, boolean_t);
285 void __s_api_conn_mt_return(ns_conn_user_t *);
286 void __s_api_conn_user_free(ns_conn_user_t *);
287 int __s_api_conn_mt_add(Connection *con, ns_conn_user_t *, ns_ldap_error_t **);
288 int __s_api_conn_mt_get(const char *, const int, const ns_cred_t *,
289 	Connection **, ns_ldap_error_t **, ns_conn_user_t *);
290 void __s_api_conn_mt_remove(ns_conn_user_t *, int, ns_ldap_error_t **);
291 int __s_api_check_libldap_MT_conn_support(ns_conn_user_t *, LDAP *ld,
292 	ns_ldap_error_t **);
293 void __s_api_conn_mt_close(ns_conn_user_t *, int, ns_ldap_error_t **);
294 void __s_api_reinit_conn_mgmt_new_config(ns_config_t *);
295 int __s_api_setup_retry_search(ns_conn_user_t **, ns_conn_user_type_t, int *,
296 	int *, ns_ldap_error_t **);
297 int __s_api_setup_getnext(ns_conn_user_t *, int *, ns_ldap_error_t **);
298 void __s_api_shutdown_conn_mgmt();
299 
300 #ifdef __cplusplus
301 }
302 #endif
303 
304 #endif /* _NS_CONNMGMT_H */
305