Beispiel #1
0
/* 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);
	}
}
Beispiel #2
0
void
dhcp_requesting(iu_tq_t *tqp, void *arg)
{
	dhcp_smach_t		*dsmp = arg;
	dhcp_pkt_t		*dpkt;
	PKT_LIST		*offer;
	lease_t			lease;
	boolean_t		isv6 = dsmp->dsm_isv6;

	/*
	 * We assume here that if tqp is set, then this means we're being
	 * called back by the offer wait timer.  If so, then drop our hold
	 * on the state machine.  Otherwise, cancel the timer if it's running.
	 */
	if (tqp != NULL) {
		dhcpmsg(MSG_VERBOSE,
		    "dhcp_requesting: offer wait timer on v%d %s",
		    isv6 ? 6 : 4, dsmp->dsm_name);
		dsmp->dsm_offer_timer = -1;
		if (!verify_smach(dsmp))
			return;
	} else {
		cancel_offer_timer(dsmp);
	}

	/*
	 * select the best OFFER; all others pitched.
	 */

	offer = select_best(dsmp);
	if (offer == NULL) {

		dhcpmsg(MSG_VERBOSE,
		    "no OFFERs/Advertisements on %s, waiting...",
		    dsmp->dsm_name);

		/*
		 * no acceptable OFFERs have come in.  reschedule
		 * ourself for callback.
		 */

		if ((dsmp->dsm_offer_timer = iu_schedule_timer(tq,
		    dsmp->dsm_offer_wait, dhcp_requesting, dsmp)) == -1) {

			/*
			 * ugh.  the best we can do at this point is
			 * revert back to INIT and wait for a user to
			 * restart us.
			 */

			dhcpmsg(MSG_WARNING, "dhcp_requesting: cannot "
			    "reschedule callback, reverting to INIT state on "
			    "%s", dsmp->dsm_name);

			stop_pkt_retransmission(dsmp);
			(void) set_smach_state(dsmp, INIT);
			dsmp->dsm_dflags |= DHCP_IF_FAILED;
			ipc_action_finish(dsmp, DHCP_IPC_E_MEMORY);
		} else {
			hold_smach(dsmp);
		}

		return;
	}

	/*
	 * With IPv4, the DHCPREQUEST packet we're about to transmit implicitly
	 * declines all other offers we've received.  We can no longer use any
	 * cached offers, so we must discard them now.  With DHCPv6, though,
	 * we're permitted to hang onto the advertisements (offers) and try
	 * them if the preferred one doesn't pan out.
	 */
	if (!isv6)
		free_pkt_list(&dsmp->dsm_recv_pkt_list);

	/* stop collecting packets. */

	stop_pkt_retransmission(dsmp);

	/*
	 * For IPv4, check to see whether we got an OFFER or a BOOTP packet.
	 * If we got a BOOTP packet, go to the BOUND state now.
	 */
	if (!isv6 && offer->opts[CD_DHCP_TYPE] == NULL) {
		free_pkt_list(&dsmp->dsm_recv_pkt_list);

		if (!set_smach_state(dsmp, REQUESTING)) {
			dhcp_restart(dsmp);
			return;
		}

		if (!dhcp_bound(dsmp, offer)) {
			dhcpmsg(MSG_WARNING, "dhcp_requesting: dhcp_bound "
			    "failed for %s", dsmp->dsm_name);
			dhcp_restart(dsmp);
			return;
		}

		return;
	}

	if (isv6) {
		const char *estr, *msg;
		const dhcpv6_option_t *d6o;
		uint_t olen, msglen;

		/* If there's a Status Code option, print the message */
		d6o = dhcpv6_pkt_option(offer, NULL, DHCPV6_OPT_STATUS_CODE,
		    &olen);
		(void) dhcpv6_status_code(d6o, olen, &estr, &msg, &msglen);
		print_server_msg(dsmp, msg, msglen);

		/* Copy in the Server ID (guaranteed to be present now) */
		if (!save_server_id(dsmp, offer))
			goto failure;

		/*
		 * Determine how to send this message.  If the Advertisement
		 * (offer) has the unicast option, then use the address
		 * specified in the option.  Otherwise, send via multicast.
		 */
		server_unicast_option(dsmp, offer);

		send_v6_request(dsmp);
	} else {
		/* if we got a message from the server, display it. */
		if (offer->opts[CD_MESSAGE] != NULL) {
			print_server_msg(dsmp,
			    (char *)offer->opts[CD_MESSAGE]->value,
			    offer->opts[CD_MESSAGE]->len);
		}

		/*
		 * assemble a DHCPREQUEST, with the ciaddr field set to 0,
		 * since we got here from the INIT state.
		 */

		dpkt = init_pkt(dsmp, REQUEST);

		/*
		 * Grab the lease out of the OFFER; we know it's valid because
		 * select_best() already checked.  The max dhcp message size
		 * option is set to the interface max, minus the size of the
		 * udp and ip headers.
		 */

		(void) memcpy(&lease, offer->opts[CD_LEASE_TIME]->value,
		    sizeof (lease_t));

		(void) add_pkt_opt32(dpkt, CD_LEASE_TIME, lease);
		(void) add_pkt_opt16(dpkt, CD_MAX_DHCP_SIZE,
		    htons(dsmp->dsm_lif->lif_max - sizeof (struct udpiphdr)));
		(void) add_pkt_opt32(dpkt, CD_REQUESTED_IP_ADDR,
		    offer->pkt->yiaddr.s_addr);
		(void) add_pkt_opt(dpkt, CD_SERVER_ID,
		    offer->opts[CD_SERVER_ID]->value,
		    offer->opts[CD_SERVER_ID]->len);

		if (class_id_len != 0) {
			(void) add_pkt_opt(dpkt, CD_CLASS_ID, class_id,
			    class_id_len);
		}
		(void) add_pkt_prl(dpkt, dsmp);

		/*
		 * dsm_reqhost was set for this state machine in
		 * dhcp_selecting() if the DF_REQUEST_HOSTNAME option set and a
		 * host name was found
		 */
		if (dsmp->dsm_reqhost != NULL) {
			(void) add_pkt_opt(dpkt, CD_HOSTNAME, dsmp->dsm_reqhost,
			    strlen(dsmp->dsm_reqhost));
		}
		(void) add_pkt_opt(dpkt, CD_END, NULL, 0);

		/*
		 * send out the REQUEST, trying retransmissions.  either a NAK
		 * or too many REQUEST attempts will revert us to SELECTING.
		 */

		if (!set_smach_state(dsmp, REQUESTING)) {
			dhcpmsg(MSG_ERROR, "dhcp_requesting: cannot switch to "
			    "REQUESTING state; reverting to INIT on %s",
			    dsmp->dsm_name);
			goto failure;
		}

		(void) send_pkt(dsmp, dpkt, htonl(INADDR_BROADCAST),
		    stop_requesting);
	}

	/* all done with the offer */
	free_pkt_entry(offer);

	return;

failure:
	dsmp->dsm_dflags |= DHCP_IF_FAILED;
	(void) set_smach_state(dsmp, INIT);
	ipc_action_finish(dsmp, DHCP_IPC_E_MEMORY);
	free_pkt_list(&dsmp->dsm_recv_pkt_list);
}
Beispiel #3
0
/* ARGSUSED */
static void
ipc_event(iu_eh_t *ehp, int fd, short events, iu_event_id_t id, void *arg)
{
	ipc_action_t		ia, *iap;
	dhcp_smach_t		*dsmp;
	int			error, is_priv = (int)arg;
	const char		*ifname;
	boolean_t		isv6;
	boolean_t		dsm_created = B_FALSE;

	ipc_action_init(&ia);
	error = dhcp_ipc_recv_request(fd, &ia.ia_request,
	    DHCP_IPC_REQUEST_WAIT);
	if (error != DHCP_IPC_SUCCESS) {
		if (error != DHCP_IPC_E_EOF) {
			dhcpmsg(MSG_ERROR,
			    "ipc_event: dhcp_ipc_recv_request failed: %s",
			    dhcp_ipc_strerror(error));
		} else {
			dhcpmsg(MSG_DEBUG, "ipc_event: connection closed");
		}
		if ((dsmp = lookup_smach_by_event(id)) != NULL) {
			ipc_action_finish(dsmp, error);
		} else {
			(void) iu_unregister_event(eh, id, NULL);
			(void) dhcp_ipc_close(fd);
		}
		return;
	}

	/* Fill in temporary ipc_action structure for utility functions */
	ia.ia_cmd = DHCP_IPC_CMD(ia.ia_request->message_type);
	ia.ia_fd = fd;
	ia.ia_eid = id;

	if (ia.ia_cmd >= DHCP_NIPC) {
		dhcpmsg(MSG_ERROR,
		    "ipc_event: invalid command (%s) attempted on %s",
		    dhcp_ipc_type_to_string(ia.ia_cmd), ia.ia_request->ifname);
		send_error_reply(&ia, DHCP_IPC_E_CMD_UNKNOWN);
		return;
	}

	/* return EPERM for any of the privileged actions */

	if (!is_priv && (ipc_cmd_flags[ia.ia_cmd] & CMD_ISPRIV)) {
		dhcpmsg(MSG_WARNING,
		    "ipc_event: privileged ipc command (%s) attempted on %s",
		    dhcp_ipc_type_to_string(ia.ia_cmd), ia.ia_request->ifname);
		send_error_reply(&ia, DHCP_IPC_E_PERM);
		return;
	}

	/*
	 * Try to locate the state machine associated with this command.  If
	 * the command is DHCP_START or DHCP_INFORM and there isn't a state
	 * machine already, make one (there may already be one from a previous
	 * failed attempt to START or INFORM).  Otherwise, verify the reference
	 * is still valid.
	 *
	 * The interface name may be blank.  In that case, we look up the
	 * primary interface, and the requested type (v4 or v6) doesn't matter.
	 */

	isv6 = (ia.ia_request->message_type & DHCP_V6) != 0;
	ifname = ia.ia_request->ifname;
	if (*ifname == '\0')
		dsmp = primary_smach(isv6);
	else
		dsmp = lookup_smach(ifname, isv6);

	if (dsmp != NULL) {
		/* Note that verify_smach drops a reference */
		hold_smach(dsmp);
		if (!verify_smach(dsmp))
			dsmp = NULL;
	}

	if (dsmp == NULL) {
		/*
		 * If the user asked for the primary DHCP interface by giving
		 * an empty string and there is no primary, then check if we're
		 * handling dhcpinfo.  If so, then simulate primary selection.
		 * Otherwise, report failure.
		 */
		if (ifname[0] == '\0') {
			if (ia.ia_cmd == DHCP_GET_TAG)
				dsmp = info_primary_smach(isv6);
			if (dsmp == NULL)
				error = DHCP_IPC_E_NOPRIMARY;

		/*
		 * If there's no interface, and we're starting up, then create
		 * it now, along with a state machine for it.  Note that if
		 * insert_smach fails, it discards the LIF reference.
		 */
		} else if (ipc_cmd_flags[ia.ia_cmd] & CMD_CREATE) {
			dhcp_lif_t *lif;

			lif = attach_lif(ifname, isv6, &error);
			if (lif != NULL &&
			    (dsmp = insert_smach(lif, &error)) != NULL) {
				/*
				 * Get client ID for logical interface.  (V4
				 * only, because V6 plumbs its own interfaces.)
				 */
				error = get_smach_cid(dsmp);
				if (error != DHCP_IPC_SUCCESS) {
					remove_smach(dsmp);
					dsmp = NULL;
				}
				dsm_created = (dsmp != NULL);
			}

		/*
		 * Otherwise, this is an operation on an unknown interface.
		 */
		} else {
			error = DHCP_IPC_E_UNKIF;
		}
		if (dsmp == NULL) {
			send_error_reply(&ia, error);
			return;
		}
	}

	/*
	 * If this is a request for DHCP to manage a lease on an address,
	 * ensure that IFF_DHCPRUNNING is set (we don't set this when the lif
	 * is created because the lif may have been created for INFORM).
	 */
	if (ia.ia_cmd == DHCP_START &&
	    (error = set_lif_dhcp(dsmp->dsm_lif)) != DHCP_IPC_SUCCESS) {
		if (dsm_created)
			remove_smach(dsmp);
		send_error_reply(&ia, error);
		return;
	}

	if ((dsmp->dsm_dflags & DHCP_IF_BOOTP) &&
	    !(ipc_cmd_flags[ia.ia_cmd] & CMD_BOOTP)) {
		dhcpmsg(MSG_ERROR, "command %s not valid for BOOTP on %s",
		    dhcp_ipc_type_to_string(ia.ia_cmd), dsmp->dsm_name);
		send_error_reply(&ia, DHCP_IPC_E_BOOTP);
		return;
	}

	/*
	 * verify that the state machine is in a state which will allow the
	 * command.  we do this up front so that we can return an error
	 * *before* needlessly cancelling an in-progress transaction.
	 */

	if (!check_cmd_allowed(dsmp->dsm_state, ia.ia_cmd)) {
		dhcpmsg(MSG_DEBUG,
		    "in state %s; not allowing %s command on %s",
		    dhcp_state_to_string(dsmp->dsm_state),
		    dhcp_ipc_type_to_string(ia.ia_cmd), dsmp->dsm_name);
		send_error_reply(&ia,
		    ia.ia_cmd == DHCP_START && dsmp->dsm_state != INIT ?
		    DHCP_IPC_E_RUNNING : DHCP_IPC_E_OUTSTATE);
		return;
	}

	dhcpmsg(MSG_DEBUG, "in state %s; allowing %s command on %s",
	    dhcp_state_to_string(dsmp->dsm_state),
	    dhcp_ipc_type_to_string(ia.ia_cmd), dsmp->dsm_name);

	if ((ia.ia_request->message_type & DHCP_PRIMARY) && is_priv)
		make_primary(dsmp);

	/*
	 * The current design dictates that there can be only one outstanding
	 * transaction per state machine -- this simplifies the code
	 * considerably and also fits well with RFCs 2131 and 3315.  It is
	 * worth classifying the different DHCP commands into synchronous
	 * (those which we will handle now and reply to immediately) and
	 * asynchronous (those which require transactions and will be completed
	 * at an indeterminate time in the future):
	 *
	 *    DROP: removes the agent's management of a state machine.
	 *	    asynchronous as the script program may be invoked.
	 *
	 *    PING: checks to see if the agent has a named state machine.
	 *	    synchronous, since no packets need to be sent
	 *	    to the DHCP server.
	 *
	 *  STATUS: returns information about a state machine.
	 *	    synchronous, since no packets need to be sent
	 *	    to the DHCP server.
	 *
	 * RELEASE: releases the agent's management of a state machine
	 *	    and brings the associated interfaces down.  asynchronous
	 *	    as the script program may be invoked.
	 *
	 *  EXTEND: renews a lease.  asynchronous, since the agent
	 *	    needs to wait for an ACK, etc.
	 *
	 *   START: starts DHCP on a named state machine.  asynchronous since
	 *	    the agent needs to wait for OFFERs, ACKs, etc.
	 *
	 *  INFORM: obtains configuration parameters for the system using
	 *	    externally configured interface.  asynchronous, since the
	 *	    agent needs to wait for an ACK.
	 *
	 * Notice that EXTEND, INFORM, START, DROP and RELEASE are
	 * asynchronous.  Notice also that asynchronous commands may occur from
	 * within the agent -- for instance, the agent will need to do implicit
	 * EXTENDs to extend the lease. In order to make the code simpler, the
	 * following rules apply for asynchronous commands:
	 *
	 * There can only be one asynchronous command at a time per state
	 * machine.  The current asynchronous command is managed by the async_*
	 * api: async_start(), async_finish(), and async_cancel().
	 * async_start() starts management of a new asynchronous command on an
	 * state machine, which should only be done after async_cancel() to
	 * terminate a previous command.  When the command is completed,
	 * async_finish() should be called.
	 *
	 * Asynchronous commands started by a user command have an associated
	 * ipc_action which provides the agent with information for how to get
	 * in touch with the user command when the action completes.  These
	 * ipc_action records also have an associated timeout which may be
	 * infinite.  ipc_action_start() should be called when starting an
	 * asynchronous command requested by a user, which sets up the timer
	 * and keeps track of the ipc information (file descriptor, request
	 * type).  When the asynchronous command completes, ipc_action_finish()
	 * should be called to return a command status code to the user and
	 * close the ipc connection).  If the command does not complete before
	 * the timer fires, ipc_action_timeout() is called which closes the ipc
	 * connection and returns DHCP_IPC_E_TIMEOUT to the user.  Note that
	 * independent of ipc_action_timeout(), ipc_action_finish() should be
	 * called.
	 *
	 * on a case-by-case basis, here is what happens (per state machine):
	 *
	 *    o When an asynchronous command is requested, then
	 *	async_cancel() is called to terminate any non-user
	 *	action in progress.  If there's a user action running,
	 *	the user command is sent DHCP_IPC_E_PEND.
	 *
	 *    o otherwise, the the transaction is started with
	 *	async_start().  if the transaction is on behalf
	 *	of a user, ipc_action_start() is called to keep
	 *	track of the ipc information and set up the
	 *	ipc_action timer.
	 *
	 *    o if the command completes normally and before a
	 *	timeout fires, then async_finish() is called.
	 *	if there was an associated ipc_action,
	 *	ipc_action_finish() is called to complete it.
	 *
	 *    o if the command fails before a timeout fires, then
	 *	async_finish() is called, and the state machine is
	 *	is returned to a known state based on the command.
	 *	if there was an associated ipc_action,
	 *	ipc_action_finish() is called to complete it.
	 *
	 *    o if the ipc_action timer fires before command
	 *	completion, then DHCP_IPC_E_TIMEOUT is returned to
	 *	the user.  however, the transaction continues to
	 *	be carried out asynchronously.
	 */

	if (ipc_cmd_flags[ia.ia_cmd] & CMD_IMMED) {
		/*
		 * Only immediate commands (ping, status, get_tag) need to
		 * worry about freeing ia through one of the reply functions
		 * before returning.
		 */
		iap = &ia;
	} else {
		/*
		 * if shutdown request has been received, send back an error.
		 */
		if (shutdown_started) {
			send_error_reply(&ia, DHCP_IPC_E_OUTSTATE);
			return;
		}

		if (dsmp->dsm_dflags & DHCP_IF_BUSY) {
			send_error_reply(&ia, DHCP_IPC_E_PEND);
			return;
		}

		if (!ipc_action_start(dsmp, &ia)) {
			dhcpmsg(MSG_WARNING, "ipc_event: ipc_action_start "
			    "failed for %s", dsmp->dsm_name);
			send_error_reply(&ia, DHCP_IPC_E_MEMORY);
			return;
		}

		/* Action structure consumed by above function */
		iap = &dsmp->dsm_ia;
	}

	switch (iap->ia_cmd) {

	case DHCP_DROP:
		if (dsmp->dsm_droprelease)
			break;
		dsmp->dsm_droprelease = B_TRUE;

		/*
		 * Ensure that a timer associated with the existing state
		 * doesn't pop while we're waiting for the script to complete.
		 * (If so, chaos can result -- e.g., a timer causes us to end
		 * up in dhcp_selecting() would start acquiring a new lease on
		 * dsmp while our DHCP_DROP dismantling is ongoing.)
		 */
		cancel_smach_timers(dsmp);
		(void) script_start(dsmp, isv6 ? EVENT_DROP6 : EVENT_DROP,
		    dhcp_drop, NULL, NULL);
		break;		/* not an immediate function */

	case DHCP_EXTEND:
		dhcp_smach_set_msg_reqhost(dsmp, iap);
		(void) dhcp_extending(dsmp);
		break;

	case DHCP_GET_TAG: {
		dhcp_optnum_t	optnum;
		void		*opt = NULL;
		uint_t		optlen;
		boolean_t	did_alloc = B_FALSE;
		PKT_LIST	*ack = dsmp->dsm_ack;
		int		i;

		/*
		 * verify the request makes sense.
		 */

		if (iap->ia_request->data_type   != DHCP_TYPE_OPTNUM ||
		    iap->ia_request->data_length != sizeof (dhcp_optnum_t)) {
			send_error_reply(iap, DHCP_IPC_E_PROTO);
			break;
		}

		(void) memcpy(&optnum, iap->ia_request->buffer,
		    sizeof (dhcp_optnum_t));

load_option:
		switch (optnum.category) {

		case DSYM_SITE:			/* FALLTHRU */
		case DSYM_STANDARD:
			for (i = 0; i < dsmp->dsm_pillen; i++) {
				if (dsmp->dsm_pil[i] == optnum.code)
					break;
			}
			if (i < dsmp->dsm_pillen)
				break;
			if (isv6) {
				opt = dhcpv6_pkt_option(ack, NULL, optnum.code,
				    NULL);
			} else {
				opt = dhcp_get_ack_or_state(dsmp, ack,
				    optnum.code, &did_alloc);
			}
			break;

		case DSYM_VENDOR:
			if (isv6) {
				dhcpv6_option_t *d6o;
				uint32_t ent;

				/*
				 * Look through vendor options to find our
				 * enterprise number.
				 */
				d6o = NULL;
				for (;;) {
					d6o = dhcpv6_pkt_option(ack, d6o,
					    DHCPV6_OPT_VENDOR_OPT, &optlen);
					if (d6o == NULL)
						break;
					optlen -= sizeof (*d6o);
					if (optlen < sizeof (ent))
						continue;
					(void) memcpy(&ent, d6o + 1,
					    sizeof (ent));
					if (ntohl(ent) != DHCPV6_SUN_ENT)
						continue;
					break;
				}
				if (d6o != NULL) {
					/*
					 * Now find the requested vendor option
					 * within the vendor options block.
					 */
					opt = dhcpv6_find_option(
					    (char *)(d6o + 1) + sizeof (ent),
					    optlen - sizeof (ent), NULL,
					    optnum.code, NULL);
				}
			} else {
				/*
				 * the test against VS_OPTION_START is broken
				 * up into two tests to avoid compiler warnings
				 * under intel.
				 */
				if ((optnum.code > VS_OPTION_START ||
				    optnum.code == VS_OPTION_START) &&
				    optnum.code <= VS_OPTION_END)
					opt = ack->vs[optnum.code];
			}
			break;

		case DSYM_FIELD:
			if (isv6) {
				dhcpv6_message_t *d6m =
				    (dhcpv6_message_t *)ack->pkt;
				dhcpv6_option_t *d6o;

				/* Validate the packet field the user wants */
				optlen = optnum.code + optnum.size;
				if (d6m->d6m_msg_type ==
				    DHCPV6_MSG_RELAY_FORW ||
				    d6m->d6m_msg_type ==
				    DHCPV6_MSG_RELAY_REPL) {
					if (optlen > sizeof (dhcpv6_relay_t))
						break;
				} else {
					if (optlen > sizeof (*d6m))
						break;
				}

				opt = malloc(sizeof (*d6o) + optnum.size);
				if (opt != NULL) {
					d6o = opt;
					d6o->d6o_code = htons(optnum.code);
					d6o->d6o_len = htons(optnum.size);
					(void) memcpy(d6o + 1, (caddr_t)d6m +
					    optnum.code, optnum.size);
				}
			} else {
				if (optnum.code + optnum.size > sizeof (PKT))
					break;

				opt = malloc(optnum.size + DHCP_OPT_META_LEN);
				if (opt != NULL) {
					DHCP_OPT *v4opt = opt;

					v4opt->len  = optnum.size;
					v4opt->code = optnum.code;
					(void) memcpy(v4opt->value,
					    (caddr_t)ack->pkt + optnum.code,
					    optnum.size);
				}
			}

			if (opt == NULL) {
				send_error_reply(iap, DHCP_IPC_E_MEMORY);
				return;
			}
			did_alloc = B_TRUE;
			break;

		default:
			send_error_reply(iap, DHCP_IPC_E_PROTO);
			return;
		}

		/*
		 * return the option payload, if there was one.
		 */

		if (opt != NULL) {
			if (isv6) {
				dhcpv6_option_t d6ov;

				(void) memcpy(&d6ov, opt, sizeof (d6ov));
				optlen = ntohs(d6ov.d6o_len) + sizeof (d6ov);
			} else {
				optlen = ((DHCP_OPT *)opt)->len +
				    DHCP_OPT_META_LEN;
			}
			send_data_reply(iap, 0, DHCP_TYPE_OPTION, opt, optlen);

			if (did_alloc)
				free(opt);
			break;
		} else if (ack != dsmp->dsm_orig_ack) {
			/*
			 * There wasn't any definition for the option in the
			 * current ack, so now retry with the original ack if
			 * the original ack is not the current ack.
			 */
			ack = dsmp->dsm_orig_ack;
			goto load_option;
		}

		/*
		 * note that an "okay" response is returned either in
		 * the case of an unknown option or a known option
		 * with no payload.  this is okay (for now) since
		 * dhcpinfo checks whether an option is valid before
		 * ever performing ipc with the agent.
		 */

		send_ok_reply(iap);
		break;
	}

	case DHCP_INFORM:
		dhcp_inform(dsmp);
		/* next destination: dhcp_acknak() */
		break;		/* not an immediate function */

	case DHCP_PING:
		if (dsmp->dsm_dflags & DHCP_IF_FAILED)
			send_error_reply(iap, DHCP_IPC_E_FAILEDIF);
		else
			send_ok_reply(iap);
		break;

	case DHCP_RELEASE:
		if (dsmp->dsm_droprelease)
			break;
		dsmp->dsm_droprelease = B_TRUE;
		cancel_smach_timers(dsmp); /* see comment in DHCP_DROP above */
		(void) script_start(dsmp, isv6 ? EVENT_RELEASE6 :
		    EVENT_RELEASE, dhcp_release, "Finished with lease.", NULL);
		break;		/* not an immediate function */

	case DHCP_START: {
		PKT_LIST *ack, *oack;
		PKT_LIST *plp[2];

		deprecate_leases(dsmp);
		dhcp_smach_set_msg_reqhost(dsmp, iap);

		/*
		 * if we have a valid hostconf lying around, then jump
		 * into INIT_REBOOT.  if it fails, we'll end up going
		 * through the whole selecting() procedure again.
		 */

		error = read_hostconf(dsmp->dsm_name, plp, 2, dsmp->dsm_isv6);
		ack = error > 0 ? plp[0] : NULL;
		oack = error > 1 ? plp[1] : NULL;

		/*
		 * If the allocation of the old ack fails, that's fine;
		 * continue without it.
		 */
		if (oack == NULL)
			oack = ack;

		/*
		 * As long as we've allocated something, start using it.
		 */
		if (ack != NULL) {
			dsmp->dsm_orig_ack = oack;
			dsmp->dsm_ack = ack;
			dhcp_init_reboot(dsmp);
			/* next destination: dhcp_acknak() */
			break;
		}

		/*
		 * if not debugging, wait for a few seconds before
		 * going into SELECTING.
		 */

		if (debug_level != 0 || !set_start_timer(dsmp)) {
			dhcp_selecting(dsmp);
			/* next destination: dhcp_requesting() */
		}
		/* else next destination: dhcp_start() */
	}
	break;

	case DHCP_STATUS: {
		dhcp_status_t	status;
		dhcp_lease_t	*dlp;

		status.if_began = monosec_to_time(dsmp->dsm_curstart_monosec);

		/*
		 * We return information on just the first lease as being
		 * representative of the lot.  A better status mechanism is
		 * needed.
		 */
		dlp = dsmp->dsm_leases;

		if (dlp == NULL ||
		    dlp->dl_lifs->lif_expire.dt_start == DHCP_PERM) {
			status.if_t1	= DHCP_PERM;
			status.if_t2	= DHCP_PERM;
			status.if_lease	= DHCP_PERM;
		} else {
			status.if_t1	= status.if_began +
			    dlp->dl_t1.dt_start;
			status.if_t2	= status.if_began +
			    dlp->dl_t2.dt_start;
			status.if_lease	= status.if_began +
			    dlp->dl_lifs->lif_expire.dt_start;
		}

		status.version		= DHCP_STATUS_VER;
		status.if_state		= dsmp->dsm_state;
		status.if_dflags	= dsmp->dsm_dflags;
		status.if_sent		= dsmp->dsm_sent;
		status.if_recv		= dsmp->dsm_received;
		status.if_bad_offers	= dsmp->dsm_bad_offers;

		(void) strlcpy(status.if_name, dsmp->dsm_name, LIFNAMSIZ);

		send_data_reply(iap, 0, DHCP_TYPE_STATUS, &status,
		    sizeof (dhcp_status_t));
		break;
	}
	}
}