/*
 * 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.
 * Copyright (c) 2016, Chris Fraire <cfraire@me.com>.
 */

#include <stdlib.h>
#include <sys/types.h>
#include <dhcpmsg.h>
#include <dhcpagent_ipc.h>

#include "agent.h"
#include "states.h"
#include "interface.h"
#include "ipc_action.h"
#include "util.h"

static iu_tq_callback_t ipc_action_timeout;

/*
 * ipc_action_init(): initializes the ipc_action structure
 *
 *   input: ipc_action_t *: the structure to initialize
 *  output: void
 */

void
ipc_action_init(ipc_action_t *ia)
{
        ia->ia_cmd = 0;
        ia->ia_fd = -1;
        ia->ia_tid = -1;
        ia->ia_eid = -1;
        ia->ia_request = NULL;
}

/*
 * ipc_action_start(): starts an ipc_action request on a DHCP state machine
 *
 *   input: dhcp_smach_t *: the state machine to start the action on
 *          ipc_action_t *: request structure
 *  output: B_TRUE if the request is started successfully, B_FALSE otherwise
 *          original request is still valid on failure, consumed otherwise.
 */

boolean_t
ipc_action_start(dhcp_smach_t *dsmp, ipc_action_t *iareq)
{
        struct ipc_action *ia = &dsmp->dsm_ia;

        if (ia->ia_fd != -1 || ia->ia_tid != -1 || iareq->ia_fd == -1) {
                dhcpmsg(MSG_CRIT, "ipc_action_start: attempted restart on %s",
                    dsmp->dsm_name);
                return (B_FALSE);
        }

        if (!async_cancel(dsmp)) {
                dhcpmsg(MSG_WARNING, "ipc_action_start: unable to cancel "
                    "action on %s", dsmp->dsm_name);
                return (B_FALSE);
        }

        if (iareq->ia_request->timeout == DHCP_IPC_WAIT_DEFAULT)
                iareq->ia_request->timeout = DHCP_IPC_DEFAULT_WAIT;

        if (iareq->ia_request->timeout == DHCP_IPC_WAIT_FOREVER) {
                iareq->ia_tid = -1;
        } else {
                iareq->ia_tid = iu_schedule_timer(tq,
                    iareq->ia_request->timeout, ipc_action_timeout, dsmp);

                if (iareq->ia_tid == -1) {
                        dhcpmsg(MSG_ERROR, "ipc_action_start: failed to set "
                            "timer for %s on %s",
                            dhcp_ipc_type_to_string(iareq->ia_cmd),
                            dsmp->dsm_name);
                        return (B_FALSE);
                }

                hold_smach(dsmp);
        }

        *ia = *iareq;

        /* We've taken ownership, so the input request is now invalid */
        ipc_action_init(iareq);

        dhcpmsg(MSG_DEBUG, "ipc_action_start: started %s (command %d) on %s,"
            " buffer length %u",
            dhcp_ipc_type_to_string(ia->ia_cmd), ia->ia_cmd, dsmp->dsm_name,
            ia->ia_request == NULL ? 0 : ia->ia_request->data_length);

        dsmp->dsm_dflags |= DHCP_IF_BUSY;

        /* This cannot fail due to the async_cancel above */
        (void) async_start(dsmp, ia->ia_cmd, B_TRUE);

        return (B_TRUE);
}

/*
 * ipc_action_finish(): completes an ipc_action request on an interface
 *
 *   input: dhcp_smach_t *: the state machine to complete the action on
 *          int: the reason why the action finished (nonzero on error)
 *  output: void
 */

void
ipc_action_finish(dhcp_smach_t *dsmp, int reason)
{
        struct ipc_action *ia = &dsmp->dsm_ia;

        dsmp->dsm_dflags &= ~DHCP_IF_BUSY;

        if (dsmp->dsm_ia.ia_fd == -1) {
                dhcpmsg(MSG_ERROR,
                    "ipc_action_finish: attempted to finish unknown action "
                    "on %s", dsmp->dsm_name);
                return;
        }

        dhcpmsg(MSG_DEBUG,
            "ipc_action_finish: finished %s (command %d) on %s: %d",
            dhcp_ipc_type_to_string(ia->ia_cmd), (int)ia->ia_cmd,
            dsmp->dsm_name, reason);

        /*
         * if we can't cancel this timer, we're really in the
         * twilight zone.  however, as long as we don't drop the
         * reference to the state machine, it shouldn't hurt us
         */

        if (dsmp->dsm_ia.ia_tid != -1 &&
            iu_cancel_timer(tq, dsmp->dsm_ia.ia_tid, NULL) == 1) {
                dsmp->dsm_ia.ia_tid = -1;
                release_smach(dsmp);
        }

        if (reason == 0)
                send_ok_reply(ia);
        else
                send_error_reply(ia, reason);

        async_finish(dsmp);
}

/*
 * ipc_action_timeout(): times out an ipc_action on a state machine (the
 *                       request continues asynchronously, however)
 *
 *   input: iu_tq_t *: unused
 *          void *: the dhcp_smach_t * the ipc_action was pending on
 *  output: void
 */

/* ARGSUSED */
static void
ipc_action_timeout(iu_tq_t *tq, void *arg)
{
        dhcp_smach_t            *dsmp = arg;
        struct ipc_action       *ia = &dsmp->dsm_ia;

        dsmp->dsm_dflags &= ~DHCP_IF_BUSY;

        ia->ia_tid = -1;

        dhcpmsg(MSG_VERBOSE, "ipc timeout waiting for agent to complete "
            "%s (command %d) for %s", dhcp_ipc_type_to_string(ia->ia_cmd),
            ia->ia_cmd, dsmp->dsm_name);

        send_error_reply(ia, DHCP_IPC_E_TIMEOUT);

        async_finish(dsmp);
        release_smach(dsmp);
}

/*
 * send_ok_reply(): sends an "ok" reply to a request and closes the ipc
 *                  connection
 *
 *   input: ipc_action_t *: the request to reply to
 *  output: void
 *    note: the request is freed (thus the request must be on the heap).
 */

void
send_ok_reply(ipc_action_t *ia)
{
        send_error_reply(ia, 0);
}

/*
 * send_error_reply(): sends an "error" reply to a request and closes the ipc
 *                     connection
 *
 *   input: ipc_action_t *: the request to reply to
 *          int: the error to send back on the ipc connection
 *  output: void
 *    note: the request is freed (thus the request must be on the heap).
 */

void
send_error_reply(ipc_action_t *ia, int error)
{
        send_data_reply(ia, error, DHCP_TYPE_NONE, NULL, 0);
}

/*
 * send_data_reply(): sends a reply to a request and closes the ipc connection
 *
 *   input: ipc_action_t *: the request to reply to
 *          int: the status to send back on the ipc connection (zero for
 *               success, DHCP_IPC_E_* otherwise).
 *          dhcp_data_type_t: the type of the payload in the reply
 *          const void *: the payload for the reply, or NULL if there is no
 *                        payload
 *          size_t: the size of the payload
 *  output: void
 *    note: the request is freed (thus the request must be on the heap).
 */

void
send_data_reply(ipc_action_t *ia, int error, dhcp_data_type_t type,
    const void *buffer, size_t size)
{
        dhcp_ipc_reply_t        *reply;
        int retval;

        if (ia->ia_fd == -1 || ia->ia_request == NULL)
                return;

        reply = dhcp_ipc_alloc_reply(ia->ia_request, error, buffer, size,
            type);
        if (reply == NULL) {
                dhcpmsg(MSG_ERR, "send_data_reply: cannot allocate reply");

        } else if ((retval = dhcp_ipc_send_reply(ia->ia_fd, reply)) != 0) {
                dhcpmsg(MSG_ERROR, "send_data_reply: dhcp_ipc_send_reply: %s",
                    dhcp_ipc_strerror(retval));
        }

        /*
         * free the request since we've now used it to send our reply.
         * we can also close the socket since the reply has been sent.
         */

        free(reply);
        free(ia->ia_request);
        if (ia->ia_eid != -1)
                (void) iu_unregister_event(eh, ia->ia_eid, NULL);
        (void) dhcp_ipc_close(ia->ia_fd);
        ia->ia_request = NULL;
        ia->ia_fd = -1;
        ia->ia_eid = -1;
}