frr/vrrpd/vrrp.c

/*
 * VRRPD global definitions
 * Copyright (C) 2018 Cumulus Networks, Inc.
 *               Quentin Young
 *
 * This program 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 2 of the License, or (at your option)
 * any later version.
 *
 * This program 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 this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include <zebra.h>

#include "memory.h"
#include "if.h"
#include "linklist.h"
#include "prefix.h"
#include "hash.h"
#include "vrf.h"
#include "hook.h"

#include "vrrp.h"

/* Utility functions ------------------------------------------------------- */

/*
 * Sets an ethaddr to RFC-defined Virtual Router MAC address.
 *
 * mac
 *    ethaddr to set
 *
 * v6
 *    Whether this is a V6 or V4 Virtual Router MAC
 *
 * vrid
 *    Virtual Router Identifier
 */
static void vrrp_mac_set(struct ethaddr *mac, bool v6, uint8_t vrid)
{
	/*
	 * V4: 00-00-5E-00-01-{VRID}
	 * V6: 00-00-5E-00-02-{VRID}
	 */
	mac->octet[0] = 0x00;
	mac->octet[1] = 0x00;
	mac->octet[2] = 0x5E;
	mac->octet[3] = 0x00;
	mac->octet[4] = v6 ? 0x02 : 0x01;
	mac->octet[5] = vrid;
}

/*
 * Sets advertisement_interval and master_adver_interval on a Virtual Router,
 * then recalculates and sets skew_time and master_down_interval based on these
 * values.
 *
 * vr
 *    Virtual Router to operate on
 *
 * advertisement_interval
 *    Advertisement_Interval to set
 *
 * master_adver_interval
 *    Master_Adver_Interval to set
 */
static void vrrp_update_times(struct vrrp_vrouter *vr, uint16_t advertisement_interval,
		       uint16_t master_adver_interval)
{
	vr->advertisement_interval = advertisement_interval;
	vr->master_adver_interval = master_adver_interval;
	vr->skew_time = (256 - vr->priority) * vr->master_adver_interval;
	vr->skew_time /= 256;
	vr->master_down_interval = (3 * vr->master_adver_interval);
	vr->master_down_interval /= 256;
}

struct vrrp_vrouter *vrrp_vrouter_create(struct interface *ifp, uint8_t vrid)
{
	struct vrrp_vrouter *vr =
		XCALLOC(MTYPE_TMP, sizeof(struct vrrp_vrouter));

	vr->sock = -1;
	vr->ifp = ifp;
	vr->vrid = vrid;
	vr->v4 = list_new();
	vr->v6 = list_new();
	vr->advint = VRRP_DEFAULT_ADVINT;
	vr->is_master = false;
	vr->priority = VRRP_DEFAULT_PRIORITY;
	vr->advertisement_interval = VRRP_DEFAULT_ADVINT;
	vr->master_adver_interval = 0;
	vr->skew_time = 0;
	vr->master_down_interval = 0;
	vr->preempt_mode = true;
	vr->accept_mode = false;
	vrrp_mac_set(&vr->vr_mac_v4, false, vrid);
	vrrp_mac_set(&vr->vr_mac_v6, true, vrid);
	vr->fsm.state = VRRP_STATE_INITIALIZE;

	hash_get(vrrp_vrouters_hash, vr, hash_alloc_intern);

	return vr;
}

struct vrrp_vrouter *vrrp_lookup(uint8_t vrid)
{
	struct vrrp_vrouter vr;
	vr.vrid = vrid;

	return hash_lookup(vrrp_vrouters_hash, &vr);
}

/* Network ----------------------------------------------------------------- */

/*
 * Create and broadcast VRRP ADVERTISEMENT message.
 *
 * vr
 *    Virtual Router for which to send ADVERTISEMENT
 */
static void vrrp_send_advertisement(struct vrrp_vrouter *vr)
{
}

/* FIXME:
static void vrrp_recv_advertisement(struct thread *thread)
{
}
*/

/*
 * Create Virtual Router listen socket and join it to the VRRP multicast group.
 *
 * The first connected address on the Virtual Router's interface is used as the
 * interface address.
 *
 * vr
 *    Virtual Router for which to create listen socket
 */
static int vrrp_socket(struct vrrp_vrouter *vr)
{
	struct ip_mreqn req;
	int ret;
	struct connected *c;

	vr->sock = socket(AF_INET, SOCK_RAW, IPPROTO_VRRP);

	if (vr->sock < 0) {
		/* FIXME */
	}

	/* Join the multicast group.*/

	 /* FIXME: Use first address on the interface and for imr_interface */
	if (!listcount(vr->ifp->connected))
		return -1;

	c = listhead(vr->ifp->connected)->data;
	struct in_addr v4 = c->address->u.prefix4;

	memset(&req, 0, sizeof(req));
	req.imr_multiaddr.s_addr = htonl(VRRP_MCAST_GROUP_HEX);
	req.imr_address = v4;
	req.imr_ifindex = 0; // FIXME: vr->ifp->ifindex ?
	ret = setsockopt(vr->sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&req,
			 sizeof(struct ip_mreq));
	if (ret < 0) {
		// int err = errno;
		/* VRRP_LOG(("cant do IP_ADD_MEMBERSHIP errno=%d\n", err)); */
		return -1;
	}
	return 0;
}


/* State machine ----------------------------------------------------------- */

DEFINE_HOOK(vrrp_change_state_hook, (struct vrrp_vrouter *vr, int to), (vr, to));

/*
 * Handle any necessary actions during state change to MASTER state.
 *
 * vr
 *    Virtual Router to operate on
 */
static void vrrp_change_state_master(struct vrrp_vrouter *vr)
{
}

/*
 * Handle any necessary actions during state change to BACKUP state.
 *
 * vr
 *    Virtual Router to operate on
 */
static void vrrp_change_state_backup(struct vrrp_vrouter *vr)
{
	/* Uninstall ARP entry for vrouter MAC */
	/* ... */
}

/*
 * Handle any necessary actions during state change to INITIALIZE state.
 *
 * This is not called for initial startup, only when transitioning from MASTER
 * or BACKUP.
 *
 * vr
 *    Virtual Router to operate on
 */
static void vrrp_change_state_initialize(struct vrrp_vrouter *vr)
{
}

void (*vrrp_change_state_handlers[])(struct vrrp_vrouter *vr) = {
	[VRRP_STATE_MASTER] = vrrp_change_state_master,
	[VRRP_STATE_BACKUP] = vrrp_change_state_backup,
	[VRRP_STATE_INITIALIZE] = vrrp_change_state_initialize,
};

/*
 * Change Virtual Router FSM position. Handles transitional actions and calls
 * any subscribers to the state change hook.
 *
 * vr
 *    Virtual Router for which to change state
 *
 * to
 *    State to change to
 */
static void vrrp_change_state(struct vrrp_vrouter *vr, int to)
{
	/* Call our handlers, then any subscribers */
	vrrp_change_state_handlers[to](vr);
	hook_call(vrrp_change_state_hook, vr, to);
	vr->fsm.state = to;
}

/*
 * Called when Adver_Timer expires.
 */
static int vrrp_adver_timer_expire(struct thread *thread)
{
	struct vrrp_vrouter *vr = thread->arg;

	if (vr->fsm.state == VRRP_STATE_BACKUP) {
		vrrp_send_advertisement(vr);
		/* FIXME: vrrp_send_gratuitous_arp(vr); */
	} else if (vr->fsm.state == VRRP_STATE_MASTER) {

	} else if (vr->fsm.state == VRRP_STATE_INITIALIZE) {
		assert(!"FUCK");
	}
	return 0;
}

/*
 * Called when Master_Down timer expires.
 */
static int vrrp_master_down_timer_expire(struct thread *thread)
{
	/* struct vrrp_vrouter *vr = thread->arg; */

	return 0;
}

/*
 * Event handler for Startup event.
 *
 * Creates sockets, sends advertisements and ARP requests, starts timers,
 * updates state machine.
 *
 * vr
 *    Virtual Router on which to apply Startup event
 */
static int vrrp_startup(struct vrrp_vrouter *vr)
{
	/* Create socket */
	int ret = vrrp_socket(vr);
	if (ret < 0) {
		zlog_warn("Cannot create VRRP socket\n");
		return ret;
	}

	/* Schedule listener */
	/* ... */

	if (vr->priority == VRRP_PRIO_MASTER) {
		vrrp_send_advertisement(vr);
		/* FIXME: vrrp_send_gratuitous_arp(vr); */

		thread_add_timer_msec(master, vrrp_adver_timer_expire, vr,
				      vr->advertisement_interval * 10,
				      &vr->t_adver_timer);
		vrrp_change_state(vr, VRRP_STATE_MASTER);
	} else {
		vrrp_update_times(vr, vr->advertisement_interval,
				  vr->advertisement_interval);
		thread_add_timer_msec(master, vrrp_master_down_timer_expire, vr,
				      vr->master_down_interval * 10,
				      &vr->t_master_down_timer);
		vrrp_change_state(vr, VRRP_STATE_BACKUP);
	}

	return 0;
}

static int vrrp_shutdown(struct vrrp_vrouter *vr)
{
	/* NOTHING */
	return 0;
}

static int (*vrrp_event_handlers[])(struct vrrp_vrouter *vr) = {
	[VRRP_EVENT_STARTUP] = vrrp_startup,
	[VRRP_EVENT_SHUTDOWN] = vrrp_shutdown,
};

/*
 * Spawn a VRRP FSM event on a Virtual Router.
 *
 * vr
 *    Virtual Router on which to spawn event
 *
 * event
 *    The event to spawn
 */
int vrrp_event(struct vrrp_vrouter *vr, int event)
{
	return vrrp_event_handlers[event](vr);
}


/* Other ------------------------------------------------------------------- */

static unsigned int vrrp_hash_key(void *arg)
{
	struct vrrp_vrouter *vr = arg;

	return vr->vrid;
}

static bool vrrp_hash_cmp(const void *arg1, const void *arg2)
{
	const struct vrrp_vrouter *vr1 = arg1;
	const struct vrrp_vrouter *vr2 = arg2;

	return vr1->vrid > vr2->vrid;
}

void vrrp_init(void)
{
	vrrp_vrouters_hash = hash_create(&vrrp_hash_key, vrrp_hash_cmp,
					 "VRRP virtual router hash");
	vrf_init(NULL, NULL, NULL, NULL, NULL);
}