xref: /onnv-gate/usr/src/cmd/cmd-inet/sbin/dhcpagent/select.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  *
26*0Sstevel@tonic-gate  * SELECTING state of the client state machine.
27*0Sstevel@tonic-gate  */
28*0Sstevel@tonic-gate 
29*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
30*0Sstevel@tonic-gate 
31*0Sstevel@tonic-gate #include <sys/types.h>
32*0Sstevel@tonic-gate #include <stdlib.h>
33*0Sstevel@tonic-gate #include <stdio.h>
34*0Sstevel@tonic-gate #include <strings.h>
35*0Sstevel@tonic-gate #include <time.h>
36*0Sstevel@tonic-gate #include <limits.h>
37*0Sstevel@tonic-gate #include <netinet/in.h>
38*0Sstevel@tonic-gate #include <sys/socket.h>
39*0Sstevel@tonic-gate #include <net/route.h>
40*0Sstevel@tonic-gate #include <net/if.h>
41*0Sstevel@tonic-gate #include <netinet/dhcp.h>
42*0Sstevel@tonic-gate #include <netinet/udp.h>
43*0Sstevel@tonic-gate #include <netinet/ip_var.h>
44*0Sstevel@tonic-gate #include <netinet/udp_var.h>
45*0Sstevel@tonic-gate #include <stropts.h>				/* FLUSHR/FLUSHW */
46*0Sstevel@tonic-gate #include <dhcpmsg.h>
47*0Sstevel@tonic-gate 
48*0Sstevel@tonic-gate #include "states.h"
49*0Sstevel@tonic-gate #include "agent.h"
50*0Sstevel@tonic-gate #include "util.h"
51*0Sstevel@tonic-gate #include "interface.h"
52*0Sstevel@tonic-gate #include "packet.h"
53*0Sstevel@tonic-gate #include "defaults.h"
54*0Sstevel@tonic-gate 
55*0Sstevel@tonic-gate static iu_eh_callback_t	dhcp_collect_offers;
56*0Sstevel@tonic-gate static stop_func_t	stop_selecting;
57*0Sstevel@tonic-gate 
58*0Sstevel@tonic-gate /*
59*0Sstevel@tonic-gate  * dhcp_start(): starts DHCP on an interface
60*0Sstevel@tonic-gate  *
61*0Sstevel@tonic-gate  *   input: iu_tq_t *: unused
62*0Sstevel@tonic-gate  *	    void *: the interface to start DHCP on
63*0Sstevel@tonic-gate  *  output: void
64*0Sstevel@tonic-gate  */
65*0Sstevel@tonic-gate 
66*0Sstevel@tonic-gate /* ARGSUSED */
67*0Sstevel@tonic-gate void
68*0Sstevel@tonic-gate dhcp_start(iu_tq_t *tqp, void *arg)
69*0Sstevel@tonic-gate {
70*0Sstevel@tonic-gate 	struct ifslist	*ifsp = (struct ifslist *)arg;
71*0Sstevel@tonic-gate 
72*0Sstevel@tonic-gate 	if (check_ifs(ifsp) == 0) {
73*0Sstevel@tonic-gate 		(void) release_ifs(ifsp);
74*0Sstevel@tonic-gate 		return;
75*0Sstevel@tonic-gate 	}
76*0Sstevel@tonic-gate 
77*0Sstevel@tonic-gate 	dhcpmsg(MSG_VERBOSE, "starting DHCP on %s", ifsp->if_name);
78*0Sstevel@tonic-gate 	dhcp_selecting(ifsp);
79*0Sstevel@tonic-gate }
80*0Sstevel@tonic-gate 
81*0Sstevel@tonic-gate /*
82*0Sstevel@tonic-gate  * dhcp_selecting(): sends a DISCOVER and sets up reception for an OFFER
83*0Sstevel@tonic-gate  *
84*0Sstevel@tonic-gate  *   input: struct ifslist *: the interface to send the DISCOVER on, ...
85*0Sstevel@tonic-gate  *  output: void
86*0Sstevel@tonic-gate  */
87*0Sstevel@tonic-gate 
88*0Sstevel@tonic-gate void
89*0Sstevel@tonic-gate dhcp_selecting(struct ifslist *ifsp)
90*0Sstevel@tonic-gate {
91*0Sstevel@tonic-gate 	dhcp_pkt_t		*dpkt;
92*0Sstevel@tonic-gate 	const char		*reqhost;
93*0Sstevel@tonic-gate 	char			hostfile[PATH_MAX + 1];
94*0Sstevel@tonic-gate 
95*0Sstevel@tonic-gate 	/*
96*0Sstevel@tonic-gate 	 * we first set up to collect OFFER packets as they arrive.
97*0Sstevel@tonic-gate 	 * we then send out DISCOVER probes.  then we wait at a
98*0Sstevel@tonic-gate 	 * user-tunable number of seconds before seeing if OFFERs have
99*0Sstevel@tonic-gate 	 * come in response to our DISCOVER.  if none have come in, we
100*0Sstevel@tonic-gate 	 * continue to wait, sending out our DISCOVER probes with
101*0Sstevel@tonic-gate 	 * exponential backoff.  if an OFFER is never received, we
102*0Sstevel@tonic-gate 	 * will wait forever (note that since we're event-driven
103*0Sstevel@tonic-gate 	 * though, we're still able to service other interfaces.)
104*0Sstevel@tonic-gate 	 *
105*0Sstevel@tonic-gate 	 * note that we do an reset_ifs() here because we may be
106*0Sstevel@tonic-gate 	 * landing in dhcp_selecting() as a result of restarting DHCP,
107*0Sstevel@tonic-gate 	 * so the ifs may not be fresh.
108*0Sstevel@tonic-gate 	 */
109*0Sstevel@tonic-gate 
110*0Sstevel@tonic-gate 	reset_ifs(ifsp);
111*0Sstevel@tonic-gate 	ifsp->if_state = SELECTING;
112*0Sstevel@tonic-gate 
113*0Sstevel@tonic-gate 	if ((ifsp->if_offer_id = iu_register_event(eh, ifsp->if_dlpi_fd, POLLIN,
114*0Sstevel@tonic-gate 	    dhcp_collect_offers, ifsp)) == -1) {
115*0Sstevel@tonic-gate 
116*0Sstevel@tonic-gate 		dhcpmsg(MSG_ERROR, "dhcp_selecting: cannot register to collect "
117*0Sstevel@tonic-gate 		    "OFFER packets, reverting to INIT on %s",
118*0Sstevel@tonic-gate 		    ifsp->if_name);
119*0Sstevel@tonic-gate 
120*0Sstevel@tonic-gate 		ifsp->if_state   = INIT;
121*0Sstevel@tonic-gate 		ifsp->if_dflags |= DHCP_IF_FAILED;
122*0Sstevel@tonic-gate 		ipc_action_finish(ifsp, DHCP_IPC_E_MEMORY);
123*0Sstevel@tonic-gate 		async_finish(ifsp);
124*0Sstevel@tonic-gate 		return;
125*0Sstevel@tonic-gate 	} else
126*0Sstevel@tonic-gate 		hold_ifs(ifsp);
127*0Sstevel@tonic-gate 
128*0Sstevel@tonic-gate 
129*0Sstevel@tonic-gate 	if (iu_schedule_timer(tq, ifsp->if_offer_wait, dhcp_requesting,
130*0Sstevel@tonic-gate 		ifsp) == -1) {
131*0Sstevel@tonic-gate 
132*0Sstevel@tonic-gate 		dhcpmsg(MSG_ERROR, "dhcp_selecting: cannot schedule to read "
133*0Sstevel@tonic-gate 		    "OFFER packets");
134*0Sstevel@tonic-gate 
135*0Sstevel@tonic-gate 		if (iu_unregister_event(eh, ifsp->if_offer_id, NULL) != 0) {
136*0Sstevel@tonic-gate 			ifsp->if_offer_id = -1;
137*0Sstevel@tonic-gate 			(void) release_ifs(ifsp);
138*0Sstevel@tonic-gate 		}
139*0Sstevel@tonic-gate 
140*0Sstevel@tonic-gate 		ifsp->if_state   = INIT;
141*0Sstevel@tonic-gate 		ifsp->if_dflags |= DHCP_IF_FAILED;
142*0Sstevel@tonic-gate 		ipc_action_finish(ifsp, DHCP_IPC_E_MEMORY);
143*0Sstevel@tonic-gate 		async_finish(ifsp);
144*0Sstevel@tonic-gate 		return;
145*0Sstevel@tonic-gate 	} else
146*0Sstevel@tonic-gate 		hold_ifs(ifsp);
147*0Sstevel@tonic-gate 
148*0Sstevel@tonic-gate 	/*
149*0Sstevel@tonic-gate 	 * Assemble DHCPDISCOVER message.  The max dhcp message size
150*0Sstevel@tonic-gate 	 * option is set to the interface max, minus the size of the udp and
151*0Sstevel@tonic-gate 	 * ip headers.
152*0Sstevel@tonic-gate 	 */
153*0Sstevel@tonic-gate 
154*0Sstevel@tonic-gate 	dpkt = init_pkt(ifsp, DISCOVER);
155*0Sstevel@tonic-gate 
156*0Sstevel@tonic-gate 	add_pkt_opt16(dpkt, CD_MAX_DHCP_SIZE, htons(ifsp->if_max -
157*0Sstevel@tonic-gate 			sizeof (struct udpiphdr)));
158*0Sstevel@tonic-gate 	add_pkt_opt32(dpkt, CD_LEASE_TIME, htonl(DHCP_PERM));
159*0Sstevel@tonic-gate 
160*0Sstevel@tonic-gate 	add_pkt_opt(dpkt, CD_CLASS_ID, class_id, class_id_len);
161*0Sstevel@tonic-gate 	add_pkt_opt(dpkt, CD_REQUEST_LIST, ifsp->if_prl, ifsp->if_prllen);
162*0Sstevel@tonic-gate 
163*0Sstevel@tonic-gate 	if (df_get_bool(ifsp->if_name, DF_REQUEST_HOSTNAME)) {
164*0Sstevel@tonic-gate 		dhcpmsg(MSG_DEBUG, "dhcp_selecting: DF_REQUEST_HOSTNAME");
165*0Sstevel@tonic-gate 		(void) snprintf(hostfile, sizeof (hostfile), "/etc/hostname.%s",
166*0Sstevel@tonic-gate 		    ifsp->if_name);
167*0Sstevel@tonic-gate 
168*0Sstevel@tonic-gate 		if ((reqhost = iffile_to_hostname(hostfile)) != NULL) {
169*0Sstevel@tonic-gate 			dhcpmsg(MSG_DEBUG, "dhcp_selecting: host %s", reqhost);
170*0Sstevel@tonic-gate 			if ((ifsp->if_reqhost = strdup(reqhost)) != NULL)
171*0Sstevel@tonic-gate 				add_pkt_opt(dpkt, CD_HOSTNAME, ifsp->if_reqhost,
172*0Sstevel@tonic-gate 				    strlen(ifsp->if_reqhost));
173*0Sstevel@tonic-gate 			else
174*0Sstevel@tonic-gate 				dhcpmsg(MSG_WARNING, "dhcp_selecting: cannot"
175*0Sstevel@tonic-gate 				    " allocate memory for host name option");
176*0Sstevel@tonic-gate 		}
177*0Sstevel@tonic-gate 	}
178*0Sstevel@tonic-gate 	add_pkt_opt(dpkt, CD_END, NULL, 0);
179*0Sstevel@tonic-gate 
180*0Sstevel@tonic-gate 	(void) send_pkt(ifsp, dpkt, htonl(INADDR_BROADCAST), stop_selecting);
181*0Sstevel@tonic-gate }
182*0Sstevel@tonic-gate 
183*0Sstevel@tonic-gate /*
184*0Sstevel@tonic-gate  * dhcp_collect_offers(): collects incoming OFFERs to a DISCOVER
185*0Sstevel@tonic-gate  *
186*0Sstevel@tonic-gate  *   input: iu_eh_t *: unused
187*0Sstevel@tonic-gate  *	    int: the file descriptor the OFFER arrived on
188*0Sstevel@tonic-gate  *	    short: unused
189*0Sstevel@tonic-gate  *	    iu_event_id_t: the id of this event callback with the handler
190*0Sstevel@tonic-gate  *	    void *: the interface that received the OFFER
191*0Sstevel@tonic-gate  *  output: void
192*0Sstevel@tonic-gate  */
193*0Sstevel@tonic-gate 
194*0Sstevel@tonic-gate /* ARGSUSED */
195*0Sstevel@tonic-gate static void
196*0Sstevel@tonic-gate dhcp_collect_offers(iu_eh_t *eh, int fd, short events, iu_event_id_t id,
197*0Sstevel@tonic-gate     void *arg)
198*0Sstevel@tonic-gate {
199*0Sstevel@tonic-gate 	struct ifslist	*ifsp = (struct ifslist *)arg;
200*0Sstevel@tonic-gate 
201*0Sstevel@tonic-gate 	if (verify_ifs(ifsp) == 0) {
202*0Sstevel@tonic-gate 		(void) ioctl(fd, I_FLUSH, FLUSHR|FLUSHW);
203*0Sstevel@tonic-gate 		return;
204*0Sstevel@tonic-gate 	}
205*0Sstevel@tonic-gate 
206*0Sstevel@tonic-gate 	/*
207*0Sstevel@tonic-gate 	 * DHCP_PUNTYPED messages are BOOTP server responses.
208*0Sstevel@tonic-gate 	 */
209*0Sstevel@tonic-gate 
210*0Sstevel@tonic-gate 	(void) recv_pkt(ifsp, fd, DHCP_POFFER|DHCP_PUNTYPED, B_TRUE);
211*0Sstevel@tonic-gate }
212*0Sstevel@tonic-gate 
213*0Sstevel@tonic-gate /*
214*0Sstevel@tonic-gate  * stop_selecting(): decides when to stop retransmitting DISCOVERs (never)
215*0Sstevel@tonic-gate  *
216*0Sstevel@tonic-gate  *   input: struct ifslist *: the interface DISCOVERs are being sent on
217*0Sstevel@tonic-gate  *	    unsigned int: the number of DISCOVERs sent so far
218*0Sstevel@tonic-gate  *  output: boolean_t: B_TRUE if retransmissions should stop
219*0Sstevel@tonic-gate  */
220*0Sstevel@tonic-gate 
221*0Sstevel@tonic-gate /* ARGSUSED */
222*0Sstevel@tonic-gate static boolean_t
223*0Sstevel@tonic-gate stop_selecting(struct ifslist *ifsp, unsigned int n_discovers)
224*0Sstevel@tonic-gate {
225*0Sstevel@tonic-gate 	return (B_FALSE);
226*0Sstevel@tonic-gate }
227