/*
 * 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 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident	"%Z%%M%	%I%	%E% SMI"

/*
 * This file contains the core logic of nwamd.
 *
 * This functionality is built around state_machine() which consumes an event.
 * The events which are input to this function are generated by either a change
 * in interface state or a signal.  The events which correspond to signals are
 * either external requests to shutdown or a timer event.  The interface events
 * indicate if an interface has acquired a new address (via DHCP) or if a new
 * interface has appeared on the system.  The latter event is used to detect new
 * links.
 *
 * state_machine() calls high level routines in llp.c and interface.c to act on
 * the state of the machine in response to events.
 */

#include <assert.h>
#include <arpa/inet.h>
#include <errno.h>
#include <libsysevent.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <netinet/in.h>
#include <pthread.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/nvpair.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/types.h>
#include <syslog.h>
#include <unistd.h>

#include "defines.h"
#include "structures.h"
#include "functions.h"
#include "variables.h"

void
state_machine(struct np_event *e)
{
	struct interface *evif;
	llp_t *evllp, *prefllp = NULL;
	uint64_t flags;
	boolean_t dhcp_restored = B_FALSE;

	dprintf("state_machine(event type: %s, name: %s)",
	    npe_type_str(e->npe_type), STRING(e->npe_name));
	switch (e->npe_type) {
	case EV_TIMER:
		/* Our timer popped; check our dhcp status. */
		if ((evif = get_interface(e->npe_name)) == NULL) {
			dprintf("couldn't find waiting interface; "
			    "ignoring EV_TIMER event");
			break;
		}
		flags = get_ifflags(evif->if_name, evif->if_family);
		if ((flags & IFF_DHCPRUNNING) == 0 || (flags & IFF_UP) != 0) {
			/*
			 * dhcp did come up successfully, or we're no
			 * longer trying to do dhcp in this interface;
			 * so no need to worry about the timer expiring.
			 */
			dprintf("timer popped for %s, but dhcp state is okay "
			    "(ifflags 0x%llx)", evif->if_name, flags);
			break;
		}
		/*
		 * dhcp has not yet completed; give up on it for
		 * now and, if it is the currently active llp,
		 * switch to the next best.
		 */
		dprintf("giving up on dhcp on %s (ifflags 0x%llx)",
		    evif->if_name, flags);
		evif->if_lflags |= IF_DHCPFAILED;
		if (interface_is_active(evif)) {
			prefllp = llp_best_avail();
			llp_swap(prefllp);
		}

		break;

	case EV_ROUTING:
		if ((evif = get_interface(e->npe_name)) == NULL ||
		    (evllp = llp_lookup(e->npe_name)) == NULL) {
			dprintf("state_machine: either no intf (%p) or no llp "
			    "(%p) for %s; ignoring EV_ROUTING event",
			    (void *)evif, (void *)evllp, STRING(e->npe_name));
			break;
		}
		prefllp = llp_best_avail();
		if (prefllp != link_layer_profile) {
			dprintf("state_machine: change in state of link %s "
			    "resulted in new preferred llp: %s (was %s)",
			    llp_prnm(evllp), llp_prnm(prefllp),
			    llp_prnm(link_layer_profile));
			llp_swap(prefllp);
		}

		break;

	case EV_NEWADDR:
		if ((evif = get_interface(e->npe_name)) == NULL ||
		    (evllp = llp_lookup(e->npe_name)) == NULL) {
			dprintf("state_machine: either no intf (%p) or no llp "
			    "(%p) for %s; ignoring EV_NEWADDR event",
			    (void *)evif, (void *)evllp, STRING(e->npe_name));
			break;
		}
		flags = get_ifflags(evif->if_name, evif->if_family);
		if (!(flags & IFF_DHCPRUNNING) && !(flags & IFF_UP) &&
		    evllp->llp_ipv4src == IPV4SRC_DHCP) {
			evif->if_timer_expire = 0;
			if ((evif->if_lflags & IF_DHCPFAILED) != 0) {
				evif->if_lflags &= ~IF_DHCPFAILED;
				dhcp_restored = B_TRUE;
			}
		}
		if (evllp != link_layer_profile) {
			if (dhcp_restored &&
			    llp_high_pri(evllp, link_layer_profile) == evllp) {
				dprintf("state_machine: dhcp completed on "
				    "higher priority llp (%s); swapping",
				    llp_prnm(evllp));
				llp_swap(evllp);
			} else {
				dprintf("state_machine: newaddr event was for "
				    "%s, not for current active link (%s); "
				    "taking down %s", evllp->llp_lname,
				    llp_prnm(link_layer_profile),
				    evllp->llp_lname);
				takedowninterface(evllp->llp_lname,
				    evllp->llp_ipv4src == IPV4SRC_DHCP, B_FALSE,
				    evllp->llp_ipv6onlink);
				break;
			}
		}
		/*
		 * An address has been assigned to the current active link.
		 * Notify the user, and activate the upper layer profile.
		 *
		 * Since other changes to the link (netmask change, broadcast
		 * addr change, etc.) can cause a NEWADDR event (XXX would
		 * be good if our event generator could do a better job
		 * filtering!), only do this if there is not currently an
		 * active ulp.
		 */
		if (!ulp_is_active()) {
			show_if_status(evllp->llp_lname);
			activate_upper_layer_profile(evllp->llp_ipv4src ==
			    IPV4SRC_DHCP, evllp->llp_lname);
		}
		break;

	case EV_SHUTDOWN:
		/* Cleanup not expecting to see any more events after this */
		cleanup();
		return;
		/* NOTREACHED */

	default:
		dprintf("unknown event");
		break;
	}
}

void
cleanup(void)
{
	if (link_layer_profile != NULL) {
		deactivate_upper_layer_profile();
		takedowninterface(link_layer_profile->llp_lname,
		    link_layer_profile->llp_ipv4src == IPV4SRC_DHCP, B_FALSE,
		    link_layer_profile->llp_ipv6onlink);
	}
	/*
	 * Since actions taken in nwamd result in dhcpagent being
	 * launched, it's under our contract.  Thus, it needs to be
	 * stopped when our stop method is executed.  But it needs
	 * to stick around long enough for us to release any leases
	 * we might have; thus, we don't want the stop method to
	 * explicitly kill it.  We do it here, when we know we've
	 * finished any dhcp cleanup that needed to be done.
	 */
	dprintf("killing dhcpagent");
	(void) start_child(PKILL, "-z", zonename, "dhcpagent", NULL);
}