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 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  * Copyright (c) 2016-2017, Chris Fraire <cfraire@me.com>.
25  */
26 
27 #ifndef	STATES_H
28 #define	STATES_H
29 
30 #include <sys/types.h>
31 #include <netinet/in.h>
32 #include <netinet/dhcp.h>
33 #include <libinetutil.h>
34 
35 #include "common.h"
36 #include "ipc_action.h"
37 #include "async.h"
38 #include "packet.h"
39 #include "util.h"
40 
41 /*
42  * interfaces for state transition/action functions.  these functions
43  * can be found in suitably named .c files, such as inform.c, select.c,
44  * renew.c, etc.
45  */
46 
47 #ifdef	__cplusplus
48 extern "C" {
49 #endif
50 
51 /*
52  * DHCP state machine representation: includes all of the information used for
53  * a state machine instance.  For IPv4, this represents a single logical
54  * interface and (usually) a leased address.  For IPv6, it represents a
55  * DUID+IAID combination.  Note that if multiple DUID+IAID instances are one
56  * day allowed per interface, this will need to become a list.
57  */
58 struct dhcp_smach_s {
59 	dhcp_smach_t	*dsm_next;	/* Note: must be first */
60 	dhcp_smach_t	*dsm_prev;
61 
62 	/*
63 	 * The name of the state machine.  This is currently just a pointer to
64 	 * the controlling LIF's name, but could be otherwise.
65 	 */
66 	const char	*dsm_name;
67 	dhcp_lif_t	*dsm_lif;	/* Controlling LIF */
68 	uint_t		dsm_hold_count;	/* reference count */
69 
70 	dhcp_lease_t	*dsm_leases;	/* List of leases */
71 	uint_t		dsm_lif_wait;	/* LIFs waiting on DAD */
72 	uint_t		dsm_lif_down;	/* LIFs failed */
73 
74 	/*
75 	 * each state machine can have at most one pending asynchronous
76 	 * action, which is represented in a `struct async_action'.
77 	 * if that asynchronous action was a result of a user request,
78 	 * then the `struct ipc_action' is used to hold information
79 	 * about the user request.  these structures are opaque to
80 	 * users of the ifslist, and the functional interfaces
81 	 * provided in async.[ch] and ipc_action.[ch] should be used
82 	 * to maintain them.
83 	 */
84 
85 	ipc_action_t	dsm_ia;
86 	async_action_t	dsm_async;
87 
88 	uchar_t		*dsm_cid;	/* client id */
89 	uchar_t		dsm_cidlen;	/* client id len */
90 
91 	/*
92 	 * current state of the machine
93 	 */
94 
95 	DHCPSTATE	dsm_state;
96 	boolean_t	dsm_droprelease;  /* soon to call finished_smach */
97 
98 	uint16_t	dsm_dflags;	/* DHCP_IF_* (shared with IPC) */
99 
100 	uint16_t	*dsm_prl;	/* if non-NULL, param request list */
101 	uint_t		dsm_prllen;	/* param request list len */
102 	uint16_t	*dsm_pil;	/* if non-NULL, param ignore list */
103 	uint_t		dsm_pillen;	/* param ignore list len */
104 
105 	uint_t		dsm_nrouters;	/* the number of default routers */
106 	struct in_addr	*dsm_routers;	/* an array of default routers */
107 
108 	in6_addr_t	dsm_server;	/* our DHCP server */
109 	uchar_t		*dsm_serverid;	/* server DUID for v6 */
110 	uint_t		dsm_serveridlen; /* DUID length */
111 
112 	/*
113 	 * We retain the very first ack obtained on the state machine to
114 	 * provide access to options which were originally assigned by
115 	 * the server but may not have been included in subsequent
116 	 * acks, as there are servers which do this and customers have
117 	 * had unsatisfactory results when using our agent with them.
118 	 * ipc_event() in agent.c provides a fallback to the original
119 	 * ack when the current ack doesn't have the information
120 	 * requested.
121 	 *
122 	 * Note that neither of these is actually a list of packets.  There's
123 	 * exactly one packet here, so use free_pkt_entry.
124 	 */
125 	PKT_LIST	*dsm_ack;
126 	PKT_LIST	*dsm_orig_ack;
127 
128 	/*
129 	 * other miscellaneous variables set or needed in the process
130 	 * of acquiring a lease.
131 	 */
132 
133 	int		dsm_offer_wait;	/* seconds between sending offers */
134 	iu_timer_id_t	dsm_offer_timer; /* timer associated with offer wait */
135 
136 	/*
137 	 * time we sent the DISCOVER relative to dsm_neg_hrtime, so that the
138 	 * REQUEST can have the same pkt->secs.
139 	 */
140 
141 	uint16_t	dsm_disc_secs;
142 
143 	/*
144 	 * this is a chain of packets which have been received on this
145 	 * state machine over some interval of time.  the packets may have
146 	 * to meet some criteria in order to be put on this list.  in
147 	 * general, packets are put on this list through recv_pkt()
148 	 */
149 
150 	PKT_LIST	*dsm_recv_pkt_list;
151 
152 	/*
153 	 * these three fields are initially zero, and get incremented
154 	 * as the ifslist goes from INIT -> BOUND.  if and when the
155 	 * ifslist moves to the RENEWING state, these fields are
156 	 * reset, so they always either indicate the number of packets
157 	 * sent, received, and declined while obtaining the current
158 	 * lease (if BOUND), or the number of packets sent, received,
159 	 * and declined while attempting to obtain a future lease
160 	 * (if any other state).
161 	 */
162 
163 	uint32_t	dsm_sent;
164 	uint32_t	dsm_received;
165 	uint32_t	dsm_bad_offers;
166 
167 	/*
168 	 * dsm_send_pkt.pkt is dynamically allocated to be as big a
169 	 * packet as we can send out on this state machine.  the remainder
170 	 * of this information is needed to make it easy to handle
171 	 * retransmissions.  note that other than dsm_bad_offers, all
172 	 * of these fields are maintained internally in send_pkt(),
173 	 * and consequently should never need to be modified by any
174 	 * other functions.
175 	 */
176 
177 	dhcp_pkt_t	dsm_send_pkt;
178 	union {
179 		struct sockaddr_in v4;
180 		struct sockaddr_in6 v6;
181 	} dsm_send_dest;
182 
183 	/*
184 	 * For v4, dsm_send_tcenter is used to track the central timer value in
185 	 * milliseconds (4000, 8000, 16000, 32000, 64000), and dsm_send_timeout
186 	 * is that value plus the +/- 1000 millisecond fuzz.
187 	 *
188 	 * For v6, dsm_send_tcenter is the MRT (maximum retransmit timer)
189 	 * value, and dsm_send_timeout must be set to the IRT (initial
190 	 * retransmit timer) value by the sender.
191 	 */
192 	uint_t		dsm_send_timeout;
193 	uint_t		dsm_send_tcenter;
194 	stop_func_t	*dsm_send_stop_func;
195 	uint32_t	dsm_packet_sent;
196 	iu_timer_id_t	dsm_retrans_timer;
197 
198 	/*
199 	 * The host name we've been asked to request is remembered
200 	 * here between the DISCOVER and the REQUEST.  (v4 only)
201 	 */
202 	char		*dsm_reqhost;
203 
204 	/*
205 	 * The host name we've been asked by IPC message (e.g.,
206 	 * `ipadm -T dhcp -h ...') to request is remembered here until it is
207 	 * reset by another external message.
208 	 */
209 	char		*dsm_msg_reqhost;
210 
211 	/*
212 	 * The domain name returned for v4 DNSdmain is decoded here for use
213 	 * (if configured and needed) to determine an FQDN.
214 	 */
215 	char		*dsm_dhcp_domainname;
216 
217 	/*
218 	 * V4 and V6 use slightly different timers.  For v4, we must count
219 	 * seconds from the point where we first try to configure the
220 	 * interface.  For v6, only seconds while performing a transaction
221 	 * matter.
222 	 *
223 	 * In v4, `dsm_neg_hrtime' represents the time since DHCP started
224 	 * configuring the interface, and is used for computing the pkt->secs
225 	 * field in v4.  In v6, it represents the time since the current
226 	 * transaction (if any) was started, and is used for the ELAPSED_TIME
227 	 * option.
228 	 *
229 	 * `dsm_newstart_monosec' represents the time the ACKed REQUEST was
230 	 * sent, which represents the start time of a new batch of leases.
231 	 * When the lease time actually begins (and thus becomes current),
232 	 * `dsm_curstart_monosec' is set to `dsm_newstart_monosec'.
233 	 */
234 	hrtime_t	dsm_neg_hrtime;
235 	monosec_t	dsm_newstart_monosec;
236 	monosec_t	dsm_curstart_monosec;
237 
238 	int		dsm_script_fd;
239 	pid_t		dsm_script_pid;
240 	pid_t		dsm_script_helper_pid;
241 	const char	*dsm_script_event;
242 	iu_event_id_t	dsm_script_event_id;
243 	void		*dsm_callback_arg;
244 	script_callback_t *dsm_script_callback;
245 
246 	iu_timer_id_t	dsm_start_timer;
247 };
248 
249 #define	dsm_isv6	dsm_lif->lif_pif->pif_isv6
250 #define	dsm_hwtype	dsm_lif->lif_pif->pif_hwtype
251 
252 struct dhcp_lease_s {
253 	dhcp_lease_t	*dl_next;	/* Note: must be first */
254 	dhcp_lease_t	*dl_prev;
255 
256 	dhcp_smach_t	*dl_smach;	/* back pointer to state machine */
257 	dhcp_lif_t	*dl_lifs;	/* LIFs configured by this lease */
258 	uint_t		dl_nlifs;	/* Number of configured LIFs */
259 	uint_t		dl_hold_count;	/* reference counter */
260 	boolean_t	dl_removed;	/* Set if removed from list */
261 	boolean_t	dl_stale;	/* not updated by Renew/bind */
262 
263 	/*
264 	 * the following fields are set when a lease is acquired, and
265 	 * may be updated over the lifetime of the lease.  they are
266 	 * all reset by reset_smach().
267 	 */
268 
269 	dhcp_timer_t	dl_t1;		/* relative renewal start time, hbo */
270 	dhcp_timer_t	dl_t2;		/* relative rebinding start time, hbo */
271 };
272 
273 /* The IU event callback functions */
274 iu_eh_callback_t	dhcp_acknak_global;
275 iu_eh_callback_t	dhcp_packet_lif;
276 
277 /* Common state-machine related routines throughout dhcpagent */
278 boolean_t	dhcp_adopt(void);
279 void		dhcp_adopt_complete(dhcp_smach_t *);
280 boolean_t	dhcp_bound(dhcp_smach_t *, PKT_LIST *);
281 void		dhcp_bound_complete(dhcp_smach_t *);
282 int		dhcp_drop(dhcp_smach_t *, void *);
283 void		dhcp_deprecate(iu_tq_t *, void *);
284 void		dhcp_expire(iu_tq_t *, void *);
285 boolean_t	dhcp_extending(dhcp_smach_t *);
286 void		dhcp_inform(dhcp_smach_t *);
287 void		dhcp_init_reboot(dhcp_smach_t *);
288 void		dhcp_rebind(iu_tq_t *, void *);
289 int		dhcp_release(dhcp_smach_t *, void *);
290 void		dhcp_renew(iu_tq_t *, void *);
291 void		dhcp_requesting(iu_tq_t *, void *);
292 void		dhcp_restart(dhcp_smach_t *);
293 void		dhcp_selecting(dhcp_smach_t *);
294 boolean_t	set_start_timer(dhcp_smach_t *);
295 void		send_declines(dhcp_smach_t *);
296 void		send_v6_request(dhcp_smach_t *);
297 boolean_t	save_server_id(dhcp_smach_t *, PKT_LIST *);
298 void		server_unicast_option(dhcp_smach_t *, PKT_LIST *);
299 
300 /* State machine support functions in states.c */
301 dhcp_smach_t	*insert_smach(dhcp_lif_t *, int *);
302 void		hold_smach(dhcp_smach_t *);
303 void		release_smach(dhcp_smach_t *);
304 void		remove_smach(dhcp_smach_t *);
305 dhcp_smach_t	*next_smach(dhcp_smach_t *, boolean_t);
306 dhcp_smach_t	*primary_smach(boolean_t);
307 dhcp_smach_t	*info_primary_smach(boolean_t);
308 void		make_primary(dhcp_smach_t *);
309 dhcp_smach_t	*lookup_smach(const char *, boolean_t);
310 dhcp_smach_t	*lookup_smach_by_uindex(uint16_t, dhcp_smach_t *, boolean_t);
311 dhcp_smach_t	*lookup_smach_by_xid(uint32_t, dhcp_smach_t *, boolean_t);
312 dhcp_smach_t	*lookup_smach_by_event(iu_event_id_t);
313 void		finished_smach(dhcp_smach_t *, int);
314 boolean_t	set_smach_state(dhcp_smach_t *, DHCPSTATE);
315 int		get_smach_cid(dhcp_smach_t *);
316 boolean_t	verify_smach(dhcp_smach_t *);
317 uint_t		smach_count(void);
318 void		reset_smach(dhcp_smach_t *);
319 void		refresh_smachs(iu_eh_t *, int, void *);
320 void		refresh_smach(dhcp_smach_t *);
321 void		nuke_smach_list(void);
322 boolean_t	schedule_smach_timer(dhcp_smach_t *, int, uint32_t,
323 		    iu_tq_callback_t *);
324 void		cancel_offer_timer(dhcp_smach_t *);
325 void		cancel_smach_timers(dhcp_smach_t *);
326 void		discard_default_routes(dhcp_smach_t *);
327 void		remove_default_routes(dhcp_smach_t *);
328 boolean_t	is_bound_state(DHCPSTATE);
329 
330 /* Lease-related support functions in states.c */
331 dhcp_lease_t	*insert_lease(dhcp_smach_t *);
332 void		hold_lease(dhcp_lease_t *);
333 void		release_lease(dhcp_lease_t *);
334 void		remove_lease(dhcp_lease_t *);
335 void		deprecate_leases(dhcp_smach_t *);
336 void		cancel_lease_timers(dhcp_lease_t *);
337 boolean_t	schedule_lease_timer(dhcp_lease_t *, dhcp_timer_t *,
338 		    iu_tq_callback_t *);
339 
340 #ifdef	__cplusplus
341 }
342 #endif
343 
344 #endif	/* STATES_H */
345