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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2016-2017, Chris Fraire <cfraire@me.com>.
*
* SELECTING state of the client state machine.
*/
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <time.h>
#include <netinet/in.h>
#include <net/route.h>
#include <net/if.h>
#include <netinet/dhcp.h>
#include <netinet/udp.h>
#include <netinet/ip_var.h>
#include <netinet/udp_var.h>
#include <dhcpmsg.h>
#include <dhcp_hostconf.h>
#include "states.h"
#include "agent.h"
#include "util.h"
#include "interface.h"
#include "packet.h"
#include "defaults.h"
static stop_func_t stop_selecting;
/*
* dhcp_start(): starts DHCP on a state machine
*
* input: iu_tq_t *: unused
* void *: the state machine on which to start DHCP
* output: void
*/
/* ARGSUSED */
static void
dhcp_start(iu_tq_t *tqp, void *arg)
{
dhcp_smach_t *dsmp = arg;
dsmp->dsm_start_timer = -1;
(void) set_smach_state(dsmp, INIT);
if (verify_smach(dsmp)) {
dhcpmsg(MSG_VERBOSE, "starting DHCP on %s", dsmp->dsm_name);
dhcp_selecting(dsmp);
}
}
/*
* set_start_timer(): sets a random timer to start a DHCP state machine
*
* input: dhcp_smach_t *: the state machine on which to start DHCP
* output: boolean_t: B_TRUE if a timer is now running
*/
boolean_t
set_start_timer(dhcp_smach_t *dsmp)
{
if (dsmp->dsm_start_timer != -1)
return (B_TRUE);
dsmp->dsm_start_timer = iu_schedule_timer_ms(tq,
lrand48() % DHCP_SELECT_WAIT, dhcp_start, dsmp);
if (dsmp->dsm_start_timer == -1)
return (B_FALSE);
hold_smach(dsmp);
return (B_TRUE);
}
/*
* dhcp_selecting(): sends a DISCOVER and sets up reception of OFFERs for
* IPv4, or sends a Solicit and sets up reception of
* Advertisements for DHCPv6.
*
* input: dhcp_smach_t *: the state machine on which to send the DISCOVER
* output: void
*/
void
dhcp_selecting(dhcp_smach_t *dsmp)
{
dhcp_pkt_t *dpkt;
/*
* We first set up to collect OFFER/Advertise packets as they arrive.
* We then send out DISCOVER/Solicit probes. Then we wait a
* user-tunable number of seconds before seeing if OFFERs/
* Advertisements have come in response to our DISCOVER/Solicit. If
* none have come in, we continue to wait, sending out our DISCOVER/
* Solicit probes with exponential backoff. If no OFFER/Advertisement
* is ever received, we will wait forever (note that since we're
* event-driven though, we're still able to service other state
* machines).
*
* Note that we do an reset_smach() here because we may be landing in
* dhcp_selecting() as a result of restarting DHCP, so the state
* machine may not be fresh.
*/
reset_smach(dsmp);
if (!set_smach_state(dsmp, SELECTING)) {
dhcpmsg(MSG_ERROR,
"dhcp_selecting: cannot switch to SELECTING state; "
"reverting to INIT on %s", dsmp->dsm_name);
goto failed;
}
/* Remove the stale hostconf file, if there is any */
(void) remove_hostconf(dsmp->dsm_name, dsmp->dsm_isv6);
dsmp->dsm_offer_timer = iu_schedule_timer(tq,
dsmp->dsm_offer_wait, dhcp_requesting, dsmp);
if (dsmp->dsm_offer_timer == -1) {
dhcpmsg(MSG_ERROR, "dhcp_selecting: cannot schedule to read "
"%s packets", dsmp->dsm_isv6 ? "Advertise" : "OFFER");
goto failed;
}
hold_smach(dsmp);
/*
* Assemble and send the DHCPDISCOVER or Solicit message.
*
* If this fails, we'll wait for the select timer to go off
* before trying again.
*/
if (dsmp->dsm_isv6) {
dhcpv6_ia_na_t d6in;
if ((dpkt = init_pkt(dsmp, DHCPV6_MSG_SOLICIT)) == NULL) {
dhcpmsg(MSG_ERROR, "dhcp_selecting: unable to set up "
"Solicit packet");
return;
}
/* Add an IA_NA option for our controlling LIF */
d6in.d6in_iaid = htonl(dsmp->dsm_lif->lif_iaid);
d6in.d6in_t1 = htonl(0);
d6in.d6in_t2 = htonl(0);
(void) add_pkt_opt(dpkt, DHCPV6_OPT_IA_NA,
(dhcpv6_option_t *)&d6in + 1,
sizeof (d6in) - sizeof (dhcpv6_option_t));
/* Option Request option for desired information */
(void) add_pkt_prl(dpkt, dsmp);
/* Enable Rapid-Commit */
(void) add_pkt_opt(dpkt, DHCPV6_OPT_RAPID_COMMIT, NULL, 0);
/* xxx add Reconfigure Accept */
(void) send_pkt_v6(dsmp, dpkt, ipv6_all_dhcp_relay_and_servers,
stop_selecting, DHCPV6_SOL_TIMEOUT, DHCPV6_SOL_MAX_RT);
} else {
if ((dpkt = init_pkt(dsmp, DISCOVER)) == NULL) {
dhcpmsg(MSG_ERROR, "dhcp_selecting: unable to set up "
"DISCOVER packet");
return;
}
/*
* The max DHCP message size option is set to the interface
* MTU, minus the size of the UDP and IP headers.
*/
(void) add_pkt_opt16(dpkt, CD_MAX_DHCP_SIZE,
htons(dsmp->dsm_lif->lif_max - sizeof (struct udpiphdr)));
(void) add_pkt_opt32(dpkt, CD_LEASE_TIME, htonl(DHCP_PERM));
if (class_id_len != 0) {
(void) add_pkt_opt(dpkt, CD_CLASS_ID, class_id,
class_id_len);
}
(void) add_pkt_prl(dpkt, dsmp);
if (!dhcp_add_fqdn_opt(dpkt, dsmp))
(void) dhcp_add_hostname_opt(dpkt, dsmp);
(void) add_pkt_opt(dpkt, CD_END, NULL, 0);
(void) send_pkt(dsmp, dpkt, htonl(INADDR_BROADCAST),
stop_selecting);
}
return;
failed:
(void) set_smach_state(dsmp, INIT);
dsmp->dsm_dflags |= DHCP_IF_FAILED;
ipc_action_finish(dsmp, DHCP_IPC_E_MEMORY);
}
/*
* stop_selecting(): decides when to stop retransmitting DISCOVERs -- only when
* abandoning the state machine. For DHCPv6, this timer may
* go off before the offer wait timer. If so, then this is a
* good time to check for valid Advertisements, so cancel the
* timer and go check.
*
* input: dhcp_smach_t *: the state machine DISCOVERs are being sent on
* unsigned int: the number of DISCOVERs sent so far
* output: boolean_t: B_TRUE if retransmissions should stop
*/
/* ARGSUSED1 */
static boolean_t
stop_selecting(dhcp_smach_t *dsmp, unsigned int n_discovers)
{
/*
* If we're using v4 and the underlying LIF we're trying to configure
* has been touched by the user, then bail out.
*/
if (!dsmp->dsm_isv6 && !verify_lif(dsmp->dsm_lif)) {
finished_smach(dsmp, DHCP_IPC_E_UNKIF);
return (B_TRUE);
}
if (dsmp->dsm_recv_pkt_list != NULL) {
dhcp_requesting(NULL, dsmp);
if (dsmp->dsm_state != SELECTING)
return (B_TRUE);
}
return (B_FALSE);
}
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