/*
 * vrrp.c - init VRRP instance and VRRP state functions
 *
 * Copyright (C) 2014 Arnaud Andre 
 *
 * This file is part of uvrrpd.
 *
 * uvrrpd is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * uvrrpd is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with uvrrpd.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdio.h>
/* pselect() */
#include <sys/select.h>
#include <signal.h>

#include "vrrp.h"
#include "vrrp_timer.h"
#include "vrrp_net.h"
#include "vrrp_state.h"
#include "vrrp_ctrl.h"

#include "uvrrpd.h"
#include "bits.h"

#include "log.h"

extern unsigned long reg;

/**
 * vrrp_init() - init struct vrrp with default values
 */
void vrrp_init(struct vrrp *vrrp)
{
	/* VRRP version */
	vrrp->version = RFC3768;

	vrrp->vrid = 0;
	vrrp->priority = PRIO_DFL;
	vrrp->naddr = 0;

	/* auth */
	vrrp->auth_type = NOAUTH;
	vrrp->auth_data = NULL;

	/* state */
	vrrp->state = INIT;
	vrrp->preempt = PREEMPT_DFL;

	/* script */
	vrrp->scriptname = NULL;
	vrrp->argv = NULL;

	/* timers */
	vrrp->adv_int = 0;
	vrrp->start_delay = 0;
	vrrp->master_adv_int = 0;
	vrrp_timer_clear(&vrrp->adv_timer);
	vrrp_timer_clear(&vrrp->masterdown_timer);
}

/**
 * vrrp_context() - dump vrrp info 
 */
static void vrrp_context(struct vrrp *vrrp)
{
	log_notice("====================");
	log_notice("VRID          %d", vrrp->vrid);
	log_notice("current_state %s", STR_STATE(vrrp->state));
	log_notice("priority      %d", vrrp->priority);
	log_notice("adv_int       %d", vrrp->adv_int);
	if (vrrp->version == RFC5798)
		log_notice("master_adv_int      %d", vrrp->master_adv_int);
	log_notice("preempt       %s", STR_PREEMPT(vrrp->preempt));
	log_notice("naddr         %d", vrrp->naddr);
	log_notice("====================");
}


/**
 * vrrp_process() - vrrp control and state machine
 */
int vrrp_process(struct vrrp *vrrp, struct vrrp_net *vnet)
{
	switch (vrrp->state) {
	case INIT:
		vrrp_state_init(vrrp, vnet);
		break;

	case BACKUP:
		vrrp_state_backup(vrrp, vnet);
		break;

	case MASTER:
		vrrp_state_master(vrrp, vnet);
		break;

	default:
		/* invalid state */
		return -ENOSYS;
		break;
	}

	if (test_and_clear_bit(UVRRPD_DUMP, &reg))
		vrrp_context(vrrp);

	return 0;
}

/**
 * vrrp_listen() - Wait for a event (VRRP pkt, msg on fifo ...)
 *
 * @return vrrp_event_t
 *   TIMER if current timer is expired
 *   another event else
 */
vrrp_event_t vrrp_listen(struct vrrp *vrrp, struct vrrp_net *vnet)
{
	struct vrrp_timer *vt;
	int max_fd;

	/* Check which timer is running
	 * Advertisement timer or Masterdown timer ? 
	 */
	if (vrrp_timer_is_running(&vrrp->adv_timer)) {
		log_debug("vrid %d :: adv_timer is running", vrrp->vrid);
		vt = &vrrp->adv_timer;
	}
	else if (vrrp_timer_is_running(&vrrp->masterdown_timer)) {
		log_debug("vrid %d :: masterdown_timer is running", vrrp->vrid);
		vt = &vrrp->masterdown_timer;
	}
	else {	/* No timer ? ... exit */
		log_error("vrid %d :: no timer running !", vrrp->vrid);
		/* TODO die() */
		exit(EXIT_FAILURE);
	}

	/* update timer before pselect() */
	if (vrrp_timer_update(vt)) {
		log_debug("vrid %d :: timer expired before pselect",
			  vrrp->vrid);
		/* timer expired or invalid */
		return TIMER;
	}

	/* pselect */
	fd_set readfds;
	FD_ZERO(&readfds);
	FD_SET(vnet->socket, &readfds);
	FD_SET(vrrp->ctrl.fd, &readfds);
	max_fd = max(vnet->socket, vrrp->ctrl.fd);

	sigset_t emptyset;
	sigemptyset(&emptyset);

	/* Wait for packet or timer expiration */
	if (pselect
	    (max_fd + 1, &readfds, NULL, NULL,
	     (const struct timespec *) &vt->delta, &emptyset) >= 0) {


		/* Timer is expired */
		if (vrrp_timer_is_expired(vt)) {
			log_debug("vrid %d :: timer expired", vrrp->vrid);
			return TIMER;
		}

		/* Else we have received a pkt */
		log_debug("vrid %d :: VRRP pkt received", vrrp->vrid);

		if (FD_ISSET(vnet->socket, &readfds)) 
			/* check if received is valid or not */
			return vrrp_net_recv(vnet, vrrp);

		if (FD_ISSET(vrrp->ctrl.fd, &readfds)) {
			return vrrp_ctrl_read(vrrp, vnet);
		}
	}
	else {	/* Signal or pselect error */
		if (errno == EINTR) {
			log_debug("vrid %d :: signal caught", vrrp->vrid);

			return SIGNAL;
		}

		log_error("vrid %d :: pselect - %m", vrrp->vrid);
	}

	return INVALID;
}


/**
 * vrrp_cleanup() - clean before exiting
 */
void vrrp_cleanup(struct vrrp *vrrp)
{
	free(vrrp->scriptname);
	free(vrrp->auth_data);
}