Adding upstream version 8.4.4.upstream/8.4.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2416 insertions, 0 deletions

diff --git a/vrrpd/vrrp.c b/vrrpd/vrrp.c
new file mode 100644
index 0000000..df749c6
--- /dev/null
+++ b/vrrpd/vrrp.c
@@ -0,0 +1,2416 @@
+/*
+ * VRRP global definitions and state machine.
+ * Copyright (C) 2018-2019 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 "lib/hash.h"
+#include "lib/hook.h"
+#include "lib/if.h"
+#include "lib/linklist.h"
+#include "lib/memory.h"
+#include "lib/network.h"
+#include "lib/prefix.h"
+#include "lib/sockopt.h"
+#include "lib/sockunion.h"
+#include "lib/vrf.h"
+#include "lib/vty.h"
+
+#include "vrrp.h"
+#include "vrrp_arp.h"
+#include "vrrp_debug.h"
+#include "vrrp_ndisc.h"
+#include "vrrp_packet.h"
+#include "vrrp_zebra.h"
+
+#define VRRP_LOGPFX "[CORE] "
+
+DEFINE_MTYPE_STATIC(VRRPD, VRRP_IP, "VRRP IP address");
+DEFINE_MTYPE_STATIC(VRRPD, VRRP_RTR, "VRRP Router");
+
+/* statics */
+struct hash *vrrp_vrouters_hash;
+bool vrrp_autoconfig_is_on;
+int vrrp_autoconfig_version;
+
+struct vrrp_defaults vd;
+
+const char *const vrrp_state_names[3] = {
+	[VRRP_STATE_INITIALIZE] = "Initialize",
+	[VRRP_STATE_MASTER] = "Master",
+	[VRRP_STATE_BACKUP] = "Backup",
+};
+
+static const char *const vrrp_event_names[2] = {
+	[VRRP_EVENT_STARTUP] = "Startup",
+	[VRRP_EVENT_SHUTDOWN] = "Shutdown",
+};
+
+
+/* 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;
+}
+
+/*
+ * Recalculates and sets skew_time and master_down_interval based
+ * values.
+ *
+ * r
+ *   VRRP Router to operate on
+ */
+static void vrrp_recalculate_timers(struct vrrp_router *r)
+{
+	uint16_t mdiadv = r->vr->version == 3 ? r->master_adver_interval
+					      : r->vr->advertisement_interval;
+	uint16_t skm = (r->vr->version == 3) ? r->master_adver_interval : 100;
+
+	r->skew_time = ((256 - r->vr->priority) * skm) / 256;
+	r->master_down_interval = 3 * mdiadv;
+	r->master_down_interval += r->skew_time;
+}
+
+/*
+ * Determines if a VRRP router is the owner of the specified address.
+ *
+ * The determining factor for whether an interface is the address owner is
+ * simply whether the address is assigned to the VRRP base interface by someone
+ * other than vrrpd.
+ *
+ * This function should always return the correct answer regardless of
+ * master/backup status.
+ *
+ * ifp
+ *    The interface to check owernship of. This should be the base interface of
+ *    a VRRP router.
+ *
+ * vr
+ *    Virtual Router
+ *
+ * Returns:
+ *    whether or not vr owns the specified address
+ */
+static bool vrrp_is_owner(struct interface *ifp, struct ipaddr *addr)
+{
+	/*
+	 * This code sanity checks implicit ownership configuration. Ideally,
+	 * the way we determine address ownership status for this VRRP router
+	 * is by looking at whether our VIPs are also assigned to the base
+	 * interface, and therefore count as "real" addresses. This frees the
+	 * user from having to manually configure priority 255 to indicate
+	 * address ownership. However, this means one of the VIPs will be used
+	 * as the source address for VRRP advertisements, which in turn means
+	 * that other VRRP routers will be receiving packets with a source
+	 * address they themselves have. This causes lots of different issues
+	 * so for now we're disabling this and forcing the user to configure
+	 * priority 255 to indicate ownership.
+	 */
+
+	return false;
+
+#if 0
+	struct prefix p;
+
+	p.family = IS_IPADDR_V4(addr) ? AF_INET : AF_INET6;
+	p.prefixlen = IS_IPADDR_V4(addr) ? IPV4_MAX_BITLEN : IPV6_MAX_BITLEN;
+	memcpy(&p.u, &addr->ip, sizeof(addr->ip));
+
+	return !!connected_lookup_prefix_exact(ifp, &p);
+#endif
+}
+
+/*
+ * Whether an interface has a MAC address that matches the VRRP RFC.
+ *
+ * ifp
+ *    Interface to check
+ *
+ * Returns:
+ *    Whether the interface has a VRRP mac or not
+ */
+static bool vrrp_ifp_has_vrrp_mac(struct interface *ifp)
+{
+	struct ethaddr vmac4;
+	struct ethaddr vmac6;
+
+	vrrp_mac_set(&vmac4, 0, 0x00);
+	vrrp_mac_set(&vmac6, 1, 0x00);
+
+	return !memcmp(ifp->hw_addr, vmac4.octet, sizeof(vmac4.octet) - 1)
+	       || !memcmp(ifp->hw_addr, vmac6.octet, sizeof(vmac6.octet) - 1);
+}
+
+/*
+ * Lookup a Virtual Router instance given a macvlan subinterface.
+ *
+ * The VRID is extracted from the interface MAC and the 2-tuple (iface, vrid)
+ * is used to look up any existing instances that match the interface. It does
+ * not matter whether the instance is already bound to the interface or not.
+ *
+ * Note that the interface linkages must be correct for this to work. In other
+ * words, the macvlan must have a valid VRRP MAC, and its link_ifindex must be
+ * be equal to the ifindex of another interface in the interface RB trees (its
+ * parent). If these conditions aren't satisfied we won't find the VR.
+ *
+ * mvl_ifp
+ *    Interface pointer to use to lookup. Should be a macvlan device.
+ *
+ * Returns:
+ *    Virtual Router, if found
+ *    NULL otherwise
+ */
+static struct vrrp_vrouter *vrrp_lookup_by_if_mvl(struct interface *mvl_ifp)
+{
+	struct interface *p;
+
+	if (!mvl_ifp || mvl_ifp->link_ifindex == 0
+	    || !vrrp_ifp_has_vrrp_mac(mvl_ifp)) {
+		if (mvl_ifp && mvl_ifp->link_ifindex == 0)
+			DEBUGD(&vrrp_dbg_zebra,
+			       VRRP_LOGPFX
+			       "Interface %s has no parent ifindex; disregarding",
+			       mvl_ifp->name);
+		if (mvl_ifp && !vrrp_ifp_has_vrrp_mac(mvl_ifp))
+			DEBUGD(&vrrp_dbg_zebra,
+			       VRRP_LOGPFX
+			       "Interface %s has a non-VRRP MAC; disregarding",
+			       mvl_ifp->name);
+		return NULL;
+	}
+
+	p = if_lookup_by_index(mvl_ifp->link_ifindex, mvl_ifp->vrf->vrf_id);
+
+	if (!p) {
+		DEBUGD(&vrrp_dbg_zebra,
+		       VRRP_LOGPFX
+		       "Tried to lookup interface %d, parent of %s, but it doesn't exist",
+		       mvl_ifp->link_ifindex, mvl_ifp->name);
+		return NULL;
+	}
+
+	uint8_t vrid = mvl_ifp->hw_addr[5];
+
+	return vrrp_lookup(p, vrid);
+}
+
+/*
+ * Lookup the Virtual Router instances configured on a particular interface.
+ *
+ * ifp
+ *    Interface pointer to use to lookup. Should not be a macvlan device.
+ *
+ * Returns:
+ *    List of virtual routers found
+ */
+static struct list *vrrp_lookup_by_if(struct interface *ifp)
+{
+	struct list *l = hash_to_list(vrrp_vrouters_hash);
+	struct listnode *ln, *nn;
+	struct vrrp_vrouter *vr;
+
+	for (ALL_LIST_ELEMENTS(l, ln, nn, vr))
+		if (vr->ifp != ifp)
+			list_delete_node(l, ln);
+
+	return l;
+}
+
+/*
+ * Lookup any Virtual Router instances associated with a particular interface.
+ * This is a combination of the results from vrrp_lookup_by_if_mvl and
+ * vrrp_lookup_by_if.
+ *
+ * Suppose the system interface list looks like the following:
+ *
+ * eth0
+ * \- eth0-v0 00:00:5e:00:01:01
+ * \- eth0-v1 00:00:5e:00:02:01
+ * \- eth0-v2 00:00:5e:00:01:0a
+ *
+ * Passing eth0-v2 to this function will give you the VRRP instance configured
+ * on eth0 with VRID 10. Passing eth0-v0 or eth0-v1 will give you the VRRP
+ * instance configured on eth0 with VRID 1. Passing eth0 will give you both.
+ *
+ * ifp
+ *    Interface pointer to use to lookup. Can be any interface.
+ *
+ * Returns:
+ *    List of virtual routers found
+ */
+static struct list *vrrp_lookup_by_if_any(struct interface *ifp)
+{
+	struct vrrp_vrouter *vr;
+	struct list *vrs;
+
+	vr = vrrp_lookup_by_if_mvl(ifp);
+	vrs = vr ? list_new() : vrrp_lookup_by_if(ifp);
+
+	if (vr)
+		listnode_add(vrs, vr);
+
+	return vrs;
+}
+
+/* Configuration controllers ----------------------------------------------- */
+
+void vrrp_check_start(struct vrrp_vrouter *vr)
+{
+	struct vrrp_router *r;
+	bool start;
+	const char *whynot = NULL;
+
+	if (vr->shutdown || vr->ifp == NULL)
+		return;
+
+	r = vr->v4;
+	/* Must not already be started */
+	start = r->fsm.state == VRRP_STATE_INITIALIZE;
+	whynot = (!start && !whynot) ? "Already running" : whynot;
+	/* Must have a parent interface */
+	start = start && (vr->ifp != NULL);
+	whynot = (!start && !whynot) ? "No base interface" : whynot;
+#if 0
+	/* Parent interface must be up */
+	start = start && if_is_operative(vr->ifp);
+	start = (!start && !whynot) ? "Base interface inoperative" : whynot;
+#endif
+	/* Parent interface must have at least one v4 */
+	start = start && connected_count_by_family(vr->ifp, AF_INET) > 0;
+	whynot = (!start && !whynot) ? "No primary IPv4 address" : whynot;
+	/* Must have a macvlan interface */
+	start = start && (r->mvl_ifp != NULL);
+	whynot = (!start && !whynot) ? "No VRRP interface" : whynot;
+#if 0
+	/* Macvlan interface must be admin up */
+	start = start && CHECK_FLAG(r->mvl_ifp->flags, IFF_UP);
+	start = (!start && !whynot) ? "Macvlan device admin down" : whynot;
+#endif
+	/* Must have at least one VIP configured */
+	start = start && r->addrs->count > 0;
+	whynot = (!start && !whynot) ? "No Virtual IP address configured"
+				     : whynot;
+	if (start)
+		vrrp_event(r, VRRP_EVENT_STARTUP);
+	else if (whynot)
+		zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "Refusing to start Virtual Router: %s",
+			  vr->vrid, family2str(r->family), whynot);
+
+	whynot = NULL;
+
+	r = vr->v6;
+	/* Must not already be started */
+	start = r->fsm.state == VRRP_STATE_INITIALIZE;
+	whynot = (!start && !whynot) ? "Already running" : whynot;
+	/* Must not be v2 */
+	start = start && vr->version != 2;
+	whynot = (!start && !whynot) ? "VRRPv2 does not support v6" : whynot;
+	/* Must have a parent interface */
+	start = start && (vr->ifp != NULL);
+	whynot = (!start && !whynot) ? "No base interface" : whynot;
+#if 0
+	/* Parent interface must be up */
+	start = start && if_is_operative(vr->ifp);
+	start = (!start && !whynot) ? "Base interface inoperative" : whynot;
+#endif
+	/* Must have a macvlan interface */
+	start = start && (r->mvl_ifp != NULL);
+	whynot = (!start && !whynot) ? "No VRRP interface" : whynot;
+#if 0
+	/* Macvlan interface must be admin up */
+	start = start && CHECK_FLAG(r->mvl_ifp->flags, IFF_UP);
+	start = (!start && !whynot) ? "Macvlan device admin down" : whynot;
+	/* Macvlan interface must have a link local */
+	start = start && connected_get_linklocal(r->mvl_ifp);
+	whynot =
+		(!start && !whynot) ? "No link local address configured" : whynot;
+	/* Macvlan interface must have a v6 IP besides the link local */
+	start = start && (connected_count_by_family(r->mvl_ifp, AF_INET6) > 1);
+	whynot = (!start && !whynot)
+			 ? "No Virtual IPv6 address configured on macvlan device"
+			 : whynot;
+#endif
+	/* Must have at least one VIP configured */
+	start = start && r->addrs->count > 0;
+	whynot =
+		(!start && !whynot) ? "No Virtual IP address configured" : whynot;
+	if (start)
+		vrrp_event(r, VRRP_EVENT_STARTUP);
+	else if (whynot)
+		zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "Refusing to start Virtual Router: %s",
+			  vr->vrid, family2str(r->family), whynot);
+}
+
+void vrrp_set_priority(struct vrrp_vrouter *vr, uint8_t priority)
+{
+	vr->priority = priority;
+	vr->v4->priority = priority;
+	vr->v6->priority = priority;
+}
+
+void vrrp_set_advertisement_interval(struct vrrp_vrouter *vr,
+				     uint16_t advertisement_interval)
+{
+	if (vr->advertisement_interval == advertisement_interval)
+		return;
+
+	vr->advertisement_interval = advertisement_interval;
+	vrrp_recalculate_timers(vr->v4);
+	vrrp_recalculate_timers(vr->v6);
+}
+
+static bool vrrp_has_ip(struct vrrp_vrouter *vr, struct ipaddr *ip)
+{
+	struct vrrp_router *r = ip->ipa_type == IPADDR_V4 ? vr->v4 : vr->v6;
+	struct listnode *ln;
+	struct ipaddr *iter;
+
+	for (ALL_LIST_ELEMENTS_RO(r->addrs, ln, iter))
+		if (!ipaddr_cmp(iter, ip))
+			return true;
+
+	return false;
+}
+
+int vrrp_add_ip(struct vrrp_vrouter *vr, struct ipaddr *ip)
+{
+	struct vrrp_router *r = IS_IPADDR_V4(ip) ? vr->v4 : vr->v6;
+	int af = r->family;
+
+	assert(r->family == af);
+	assert(!(r->vr->version == 2 && ip->ipa_type == IPADDR_V6));
+
+	if (vrrp_has_ip(r->vr, ip))
+		return 0;
+
+	if (!vrrp_is_owner(r->vr->ifp, ip) && r->is_owner) {
+		char ipbuf[INET6_ADDRSTRLEN];
+
+		inet_ntop(r->family, &ip->ip, ipbuf, sizeof(ipbuf));
+		zlog_err(
+			VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			"This VRRP router is not the address owner of %s, but is the address owner of other addresses; this config is unsupported.",
+			r->vr->vrid, family2str(r->family), ipbuf);
+		return -1;
+	}
+
+	struct ipaddr *new = XCALLOC(MTYPE_VRRP_IP, sizeof(struct ipaddr));
+
+	*new = *ip;
+	listnode_add(r->addrs, new);
+
+	if (r->fsm.state == VRRP_STATE_MASTER) {
+		switch (r->family) {
+		case AF_INET:
+			vrrp_garp_send(r, &new->ipaddr_v4);
+			break;
+		case AF_INET6:
+			vrrp_ndisc_una_send(r, new);
+			break;
+		}
+	}
+
+	return 0;
+}
+
+int vrrp_add_ipv4(struct vrrp_vrouter *vr, struct in_addr v4)
+{
+	struct ipaddr ip;
+
+	ip.ipa_type = IPADDR_V4;
+	ip.ipaddr_v4 = v4;
+	return vrrp_add_ip(vr, &ip);
+}
+
+int vrrp_add_ipv6(struct vrrp_vrouter *vr, struct in6_addr v6)
+{
+	assert(vr->version != 2);
+
+	struct ipaddr ip;
+
+	ip.ipa_type = IPADDR_V6;
+	ip.ipaddr_v6 = v6;
+	return vrrp_add_ip(vr, &ip);
+}
+
+int vrrp_del_ip(struct vrrp_vrouter *vr, struct ipaddr *ip)
+{
+	struct listnode *ln, *nn;
+	struct ipaddr *iter;
+	int ret = 0;
+
+	struct vrrp_router *r = IS_IPADDR_V4(ip) ? vr->v4 : vr->v6;
+
+	if (!vrrp_has_ip(r->vr, ip))
+		return 0;
+
+	for (ALL_LIST_ELEMENTS(r->addrs, ln, nn, iter))
+		if (!ipaddr_cmp(iter, ip))
+			list_delete_node(r->addrs, ln);
+
+	/*
+	 * NB: Deleting the last address and then issuing a shutdown will cause
+	 * transmission of a priority 0 VRRP Advertisement - as per the RFC -
+	 * but it will have no addresses. This is not forbidden in the RFC but
+	 * might confuse other implementations.
+	 */
+	if (r->addrs->count == 0 && r->fsm.state != VRRP_STATE_INITIALIZE)
+		ret = vrrp_event(r, VRRP_EVENT_SHUTDOWN);
+
+	return ret;
+}
+
+int vrrp_del_ipv6(struct vrrp_vrouter *vr, struct in6_addr v6)
+{
+	struct ipaddr ip;
+
+	ip.ipa_type = IPADDR_V6;
+	ip.ipaddr_v6 = v6;
+	return vrrp_del_ip(vr, &ip);
+}
+
+int vrrp_del_ipv4(struct vrrp_vrouter *vr, struct in_addr v4)
+{
+	struct ipaddr ip;
+
+	ip.ipa_type = IPADDR_V4;
+	ip.ipaddr_v4 = v4;
+	return vrrp_del_ip(vr, &ip);
+}
+
+
+/* Creation and destruction ------------------------------------------------ */
+
+static void vrrp_router_addr_list_del_cb(void *val)
+{
+	struct ipaddr *ip = val;
+
+	XFREE(MTYPE_VRRP_IP, ip);
+}
+
+/*
+ * Search for a suitable macvlan subinterface we can attach to, and if found,
+ * attach to it.
+ *
+ * r
+ *    Router to attach to interface
+ *
+ * Returns:
+ *    Whether an interface was successfully attached
+ */
+static bool vrrp_attach_interface(struct vrrp_router *r)
+{
+	/* Search for existing interface with computed MAC address */
+	struct interface **ifps;
+
+	size_t ifps_cnt =
+		if_lookup_by_hwaddr(r->vmac.octet, sizeof(r->vmac.octet), &ifps,
+				    r->vr->ifp->vrf->vrf_id);
+
+	/*
+	 * Filter to only those macvlan interfaces whose parent is the base
+	 * interface this VRRP router is configured on.
+	 *
+	 * If there are still multiple interfaces we just select the first one,
+	 * as it should be functionally identical to the others.
+	 */
+	unsigned int candidates = 0;
+	struct interface *selection = NULL;
+
+	for (unsigned int i = 0; i < ifps_cnt; i++) {
+		if (ifps[i]->link_ifindex != r->vr->ifp->ifindex)
+			ifps[i] = NULL;
+		else {
+			selection = selection ? selection : ifps[i];
+			candidates++;
+		}
+	}
+
+	if (ifps_cnt)
+		XFREE(MTYPE_TMP, ifps);
+
+	char ethstr[ETHER_ADDR_STRLEN];
+
+	prefix_mac2str(&r->vmac, ethstr, sizeof(ethstr));
+
+	assert(!!selection == !!candidates);
+
+	if (candidates == 0)
+		zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "Interface: None (no interface found w/ MAC %s)",
+			  r->vr->vrid, family2str(r->family), ethstr);
+	else if (candidates > 1)
+		zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "Interface: Multiple interfaces found; using %s",
+			  r->vr->vrid, family2str(r->family), selection->name);
+	else
+		zlog_info(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "Interface: %s",
+			  r->vr->vrid, family2str(r->family), selection->name);
+
+	r->mvl_ifp = selection;
+
+	return !!r->mvl_ifp;
+}
+
+static struct vrrp_router *vrrp_router_create(struct vrrp_vrouter *vr,
+					      int family)
+{
+	struct vrrp_router *r =
+		XCALLOC(MTYPE_VRRP_RTR, sizeof(struct vrrp_router));
+
+	r->family = family;
+	r->sock_rx = -1;
+	r->sock_tx = -1;
+	r->vr = vr;
+	r->addrs = list_new();
+	r->addrs->del = vrrp_router_addr_list_del_cb;
+	r->priority = vr->priority;
+	r->fsm.state = VRRP_STATE_INITIALIZE;
+	vrrp_mac_set(&r->vmac, family == AF_INET6, vr->vrid);
+
+	vrrp_attach_interface(r);
+
+	return r;
+}
+
+static void vrrp_router_destroy(struct vrrp_router *r)
+{
+	if (r->is_active)
+		vrrp_event(r, VRRP_EVENT_SHUTDOWN);
+
+	if (r->sock_rx >= 0)
+		close(r->sock_rx);
+	if (r->sock_tx >= 0)
+		close(r->sock_tx);
+
+	/* FIXME: also delete list elements */
+	list_delete(&r->addrs);
+	XFREE(MTYPE_VRRP_RTR, r);
+}
+
+struct vrrp_vrouter *vrrp_vrouter_create(struct interface *ifp, uint8_t vrid,
+					 uint8_t version)
+{
+	struct vrrp_vrouter *vr = vrrp_lookup(ifp, vrid);
+
+	if (vr)
+		return vr;
+
+	if (version != 2 && version != 3)
+		return NULL;
+
+	vr = XCALLOC(MTYPE_VRRP_RTR, sizeof(struct vrrp_vrouter));
+
+	vr->ifp = ifp;
+	vr->version = version;
+	vr->vrid = vrid;
+	vr->priority = vd.priority;
+	vr->preempt_mode = vd.preempt_mode;
+	vr->accept_mode = vd.accept_mode;
+	vr->shutdown = vd.shutdown;
+
+	vr->v4 = vrrp_router_create(vr, AF_INET);
+	vr->v6 = vrrp_router_create(vr, AF_INET6);
+
+	vrrp_set_advertisement_interval(vr, vd.advertisement_interval);
+
+	(void)hash_get(vrrp_vrouters_hash, vr, hash_alloc_intern);
+
+	return vr;
+}
+
+void vrrp_vrouter_destroy(struct vrrp_vrouter *vr)
+{
+	vrrp_router_destroy(vr->v4);
+	vrrp_router_destroy(vr->v6);
+	hash_release(vrrp_vrouters_hash, vr);
+	XFREE(MTYPE_VRRP_RTR, vr);
+}
+
+struct vrrp_vrouter *vrrp_lookup(const struct interface *ifp, uint8_t vrid)
+{
+	if (!ifp)
+		return NULL;
+
+	struct vrrp_vrouter vr;
+
+	vr.vrid = vrid;
+	vr.ifp = (struct interface *)ifp;
+
+	return hash_lookup(vrrp_vrouters_hash, &vr);
+}
+
+/* Network ----------------------------------------------------------------- */
+
+/* Forward decls */
+static void vrrp_change_state(struct vrrp_router *r, int to);
+static void vrrp_adver_timer_expire(struct thread *thread);
+static void vrrp_master_down_timer_expire(struct thread *thread);
+
+/*
+ * Finds the first connected address of the appropriate family on a VRRP
+ * router's interface and binds the Tx socket of the VRRP router to that
+ * address.
+ *
+ * Also sets src field of vrrp_router.
+ *
+ * r
+ *    VRRP router to operate on
+ *
+ * Returns:
+ *     0 on success
+ *    -1 on failure
+ */
+static int vrrp_bind_to_primary_connected(struct vrrp_router *r)
+{
+	struct interface *ifp;
+
+	/*
+	 * A slight quirk: the RFC specifies that advertisements under IPv6 must
+	 * be transmitted using the link local address of the source interface
+	 */
+	ifp = r->family == AF_INET ? r->vr->ifp : r->mvl_ifp;
+
+	struct listnode *ln;
+	struct connected *c = NULL;
+
+	for (ALL_LIST_ELEMENTS_RO(ifp->connected, ln, c))
+		if (c->address->family == r->family) {
+			if (r->family == AF_INET6
+			    && IN6_IS_ADDR_LINKLOCAL(&c->address->u.prefix6))
+				break;
+			else if (r->family == AF_INET)
+				break;
+		}
+
+	if (c == NULL) {
+		zlog_err(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			 "Failed to find address to bind on %s",
+			 r->vr->vrid, family2str(r->family), ifp->name);
+		return -1;
+	}
+
+	union sockunion su;
+
+	memset(&su, 0x00, sizeof(su));
+
+	switch (r->family) {
+	case AF_INET:
+		r->src.ipa_type = IPADDR_V4;
+		r->src.ipaddr_v4 = c->address->u.prefix4;
+		su.sin.sin_family = AF_INET;
+		su.sin.sin_addr = c->address->u.prefix4;
+		break;
+	case AF_INET6:
+		r->src.ipa_type = IPADDR_V6;
+		r->src.ipaddr_v6 = c->address->u.prefix6;
+		su.sin6.sin6_family = AF_INET6;
+		su.sin6.sin6_scope_id = ifp->ifindex;
+		su.sin6.sin6_addr = c->address->u.prefix6;
+		break;
+	}
+
+	int ret = 0;
+
+	sockopt_reuseaddr(r->sock_tx);
+	if (bind(r->sock_tx, (const struct sockaddr *)&su, sizeof(su)) < 0) {
+		zlog_err(
+			VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			"Failed to bind Tx socket to primary IP address %pFX: %s",
+			r->vr->vrid, family2str(r->family), c->address,
+			safe_strerror(errno));
+		ret = -1;
+	} else {
+		DEBUGD(&vrrp_dbg_sock,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Bound Tx socket to primary IP address %pFX",
+		       r->vr->vrid, family2str(r->family), c->address);
+	}
+
+	return ret;
+}
+
+
+/*
+ * Create and multicast a VRRP ADVERTISEMENT message.
+ *
+ * r
+ *    VRRP Router for which to send ADVERTISEMENT
+ */
+static void vrrp_send_advertisement(struct vrrp_router *r)
+{
+	struct vrrp_pkt *pkt;
+	ssize_t pktsz;
+	struct ipaddr *addrs[r->addrs->count];
+	union sockunion dest;
+
+	if (r->src.ipa_type == IPADDR_NONE
+	    && vrrp_bind_to_primary_connected(r) < 0)
+		return;
+
+	list_to_array(r->addrs, (void **)addrs, r->addrs->count);
+
+	pktsz = vrrp_pkt_adver_build(&pkt, &r->src, r->vr->version, r->vr->vrid,
+				     r->priority, r->vr->advertisement_interval,
+				     r->addrs->count, (struct ipaddr **)&addrs);
+
+	if (DEBUG_MODE_CHECK(&vrrp_dbg_pkt, DEBUG_MODE_ALL))
+		zlog_hexdump(pkt, (size_t)pktsz);
+
+	const char *group = r->family == AF_INET ? VRRP_MCASTV4_GROUP_STR
+						 : VRRP_MCASTV6_GROUP_STR;
+	(void)str2sockunion(group, &dest);
+
+	ssize_t sent = sendto(r->sock_tx, pkt, (size_t)pktsz, 0, &dest.sa,
+			      sockunion_sizeof(&dest));
+
+	vrrp_pkt_free(pkt);
+
+	if (sent < 0) {
+		zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "Failed to send VRRP Advertisement: %s",
+			  r->vr->vrid, family2str(r->family),
+			  safe_strerror(errno));
+	} else {
+		++r->stats.adver_tx_cnt;
+	}
+}
+
+/*
+ * Receive and parse VRRP advertisement.
+ *
+ * By the time we get here all fields have been validated for basic correctness
+ * and the packet is a valid VRRP packet.
+ *
+ * However, we have not validated whether the VRID is correct for this virtual
+ * router, nor whether the priority is correct (i.e. is not 255 when we are the
+ * address owner), nor whether the advertisement interval equals our own
+ * configured value (this check is only performed in VRRPv2).
+ *
+ * r
+ *    VRRP Router associated with the socket this advertisement was received on
+ *
+ * src
+ *    Source address of sender
+ *
+ * pkt
+ *    The advertisement they sent
+ *
+ * pktsize
+ *    Size of advertisement
+ *
+ * Returns:
+ *    -1 if advertisement is invalid
+ *     0 otherwise
+ */
+static int vrrp_recv_advertisement(struct vrrp_router *r, struct ipaddr *src,
+				   struct vrrp_pkt *pkt, size_t pktsize)
+{
+	char sipstr[INET6_ADDRSTRLEN];
+	char dipstr[INET6_ADDRSTRLEN];
+
+	ipaddr2str(src, sipstr, sizeof(sipstr));
+	ipaddr2str(&r->src, dipstr, sizeof(dipstr));
+
+	char dumpbuf[BUFSIZ];
+
+	vrrp_pkt_adver_dump(dumpbuf, sizeof(dumpbuf), pkt);
+	DEBUGD(&vrrp_dbg_proto,
+	       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+	       "Received VRRP Advertisement from %s: %s",
+	       r->vr->vrid, family2str(r->family), sipstr, dumpbuf);
+
+	/* Check that VRID matches our configured VRID */
+	if (pkt->hdr.vrid != r->vr->vrid) {
+		DEBUGD(&vrrp_dbg_proto,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Datagram invalid: Advertisement contains VRID %hhu which does not match our instance",
+		       r->vr->vrid, family2str(r->family), pkt->hdr.vrid);
+		return -1;
+	}
+
+	/* Verify that we are not the IPvX address owner */
+	if (r->is_owner) {
+		DEBUGD(&vrrp_dbg_proto,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Datagram invalid: Received advertisement but we are the address owner",
+		       r->vr->vrid, family2str(r->family));
+		return -1;
+	}
+
+	/* If v2, verify that adver time matches ours */
+	bool adveq = (pkt->hdr.v2.adver_int
+		      == MAX(r->vr->advertisement_interval / 100, 1));
+	if (r->vr->version == 2 && !adveq) {
+		DEBUGD(&vrrp_dbg_proto,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Datagram invalid: Received advertisement with advertisement interval %hhu unequal to our configured value %u",
+		       r->vr->vrid, family2str(r->family),
+		       pkt->hdr.v2.adver_int,
+		       MAX(r->vr->advertisement_interval / 100, 1));
+		return -1;
+	}
+
+
+	/* Check that # IPs received matches our # configured IPs */
+	if (pkt->hdr.naddr != r->addrs->count)
+		DEBUGD(&vrrp_dbg_proto,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Datagram has %hhu addresses, but this VRRP instance has %u",
+		       r->vr->vrid, family2str(r->family), pkt->hdr.naddr,
+		       r->addrs->count);
+
+	++r->stats.adver_rx_cnt;
+
+	int addrcmp;
+
+	switch (r->fsm.state) {
+	case VRRP_STATE_MASTER:
+		addrcmp = ipaddr_cmp(src, &r->src);
+
+		if (pkt->hdr.priority == 0) {
+			vrrp_send_advertisement(r);
+			THREAD_OFF(r->t_adver_timer);
+			thread_add_timer_msec(
+				master, vrrp_adver_timer_expire, r,
+				r->vr->advertisement_interval * CS2MS,
+				&r->t_adver_timer);
+		} else if (pkt->hdr.priority > r->priority
+			   || ((pkt->hdr.priority == r->priority)
+			       && addrcmp > 0)) {
+			zlog_info(
+				VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				"Received advertisement from %s w/ priority %hhu; switching to Backup",
+				r->vr->vrid, family2str(r->family), sipstr,
+				pkt->hdr.priority);
+			THREAD_OFF(r->t_adver_timer);
+			if (r->vr->version == 3) {
+				r->master_adver_interval =
+					htons(pkt->hdr.v3.adver_int);
+			}
+			vrrp_recalculate_timers(r);
+			THREAD_OFF(r->t_master_down_timer);
+			thread_add_timer_msec(master,
+					      vrrp_master_down_timer_expire, r,
+					      r->master_down_interval * CS2MS,
+					      &r->t_master_down_timer);
+			vrrp_change_state(r, VRRP_STATE_BACKUP);
+		} else {
+			/* Discard advertisement */
+			DEBUGD(&vrrp_dbg_proto,
+			       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			       "Discarding advertisement from %s (%hhu <= %hhu & %s <= %s)",
+			       r->vr->vrid, family2str(r->family), sipstr,
+			       pkt->hdr.priority, r->priority, sipstr, dipstr);
+		}
+		break;
+	case VRRP_STATE_BACKUP:
+		if (pkt->hdr.priority == 0) {
+			THREAD_OFF(r->t_master_down_timer);
+			thread_add_timer_msec(
+				master, vrrp_master_down_timer_expire, r,
+				r->skew_time * CS2MS, &r->t_master_down_timer);
+		} else if (!r->vr->preempt_mode
+			   || pkt->hdr.priority >= r->priority) {
+			if (r->vr->version == 3) {
+				r->master_adver_interval =
+					ntohs(pkt->hdr.v3.adver_int);
+			}
+			vrrp_recalculate_timers(r);
+			THREAD_OFF(r->t_master_down_timer);
+			thread_add_timer_msec(master,
+					      vrrp_master_down_timer_expire, r,
+					      r->master_down_interval * CS2MS,
+					      &r->t_master_down_timer);
+		} else if (r->vr->preempt_mode
+			   && pkt->hdr.priority < r->priority) {
+			/* Discard advertisement */
+			DEBUGD(&vrrp_dbg_proto,
+			       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			       "Discarding advertisement from %s (%hhu < %hhu & preempt = true)",
+			       r->vr->vrid, family2str(r->family), sipstr,
+			       pkt->hdr.priority, r->priority);
+		}
+		break;
+	case VRRP_STATE_INITIALIZE:
+		zlog_err(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			 "Received ADVERTISEMENT in state %s; this is a bug",
+			 r->vr->vrid, family2str(r->family),
+			 vrrp_state_names[r->fsm.state]);
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ * Read and process next IPvX datagram.
+ */
+static void vrrp_read(struct thread *thread)
+{
+	struct vrrp_router *r = THREAD_ARG(thread);
+
+	struct vrrp_pkt *pkt;
+	ssize_t pktsize;
+	ssize_t nbytes;
+	bool resched;
+	char errbuf[BUFSIZ];
+	struct sockaddr_storage sa;
+	uint8_t control[64];
+	struct ipaddr src = {};
+
+	struct msghdr m = {};
+	struct iovec iov;
+
+	iov.iov_base = r->ibuf;
+	iov.iov_len = sizeof(r->ibuf);
+	m.msg_name = &sa;
+	m.msg_namelen = sizeof(sa);
+	m.msg_iov = &iov;
+	m.msg_iovlen = 1;
+	m.msg_control = control;
+	m.msg_controllen = sizeof(control);
+
+	nbytes = recvmsg(r->sock_rx, &m, MSG_DONTWAIT);
+
+	if ((nbytes < 0 && ERRNO_IO_RETRY(errno))) {
+		resched = true;
+		goto done;
+	} else if (nbytes <= 0) {
+		vrrp_event(r, VRRP_EVENT_SHUTDOWN);
+		resched = false;
+		goto done;
+	}
+
+	if (DEBUG_MODE_CHECK(&vrrp_dbg_pkt, DEBUG_MODE_ALL)) {
+		DEBUGD(&vrrp_dbg_pkt,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Datagram rx: ",
+		       r->vr->vrid, family2str(r->family));
+		zlog_hexdump(r->ibuf, nbytes);
+	}
+
+	pktsize = vrrp_pkt_parse_datagram(r->family, r->vr->version, &m, nbytes,
+					  &src, &pkt, errbuf, sizeof(errbuf));
+
+	if (pktsize < 0)
+		DEBUGD(&vrrp_dbg_pkt,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Datagram invalid: %s",
+		       r->vr->vrid, family2str(r->family), errbuf);
+	else
+		vrrp_recv_advertisement(r, &src, pkt, pktsize);
+
+	resched = true;
+
+done:
+	memset(r->ibuf, 0x00, sizeof(r->ibuf));
+
+	if (resched)
+		thread_add_read(master, vrrp_read, r, r->sock_rx, &r->t_read);
+}
+
+/*
+ * Creates and configures VRRP router sockets.
+ *
+ * This function:
+ * - Creates two sockets, one for Tx, one for Rx
+ * - Binds the Tx socket to the macvlan device, if necessary (VRF case)
+ * - Binds the Rx socket to the base interface
+ * - Joins the Rx socket to the appropriate VRRP multicast group
+ * - Sets the Tx socket to set the TTL (v4) or Hop Limit (v6) field to 255 for
+ *   all transmitted IPvX packets
+ * - Requests the kernel to deliver IPv6 header values needed to validate VRRP
+ *   packets
+ *
+ * If any of the above fail, the sockets are closed. The only exception is if
+ * the TTL / Hop Limit settings fail; these are logged, but configuration
+ * proceeds.
+ *
+ * The first connected address on the Virtual Router's interface is used as the
+ * interface address.
+ *
+ * r
+ *    VRRP Router for which to create listen socket
+ *
+ * Returns:
+ *     0 on success
+ *    -1 on failure
+ */
+static int vrrp_socket(struct vrrp_router *r)
+{
+	int ret;
+	bool failed = false;
+
+	frr_with_privs(&vrrp_privs) {
+		r->sock_rx = vrf_socket(r->family, SOCK_RAW, IPPROTO_VRRP,
+					r->vr->ifp->vrf->vrf_id, NULL);
+		r->sock_tx = vrf_socket(r->family, SOCK_RAW, IPPROTO_VRRP,
+					r->vr->ifp->vrf->vrf_id, NULL);
+	}
+
+	if (r->sock_rx < 0 || r->sock_tx < 0) {
+		const char *rxtx = r->sock_rx < 0 ? "Rx" : "Tx";
+
+		zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "Can't create VRRP %s socket",
+			  r->vr->vrid, family2str(r->family), rxtx);
+		failed = true;
+		goto done;
+	}
+
+	/*
+	 * Bind Tx socket to macvlan device - necessary for VRF support,
+	 * otherwise the kernel will select the vrf device
+	 */
+	if (r->vr->ifp->vrf->vrf_id != VRF_DEFAULT) {
+		frr_with_privs (&vrrp_privs) {
+			ret = setsockopt(r->sock_tx, SOL_SOCKET,
+					 SO_BINDTODEVICE, r->mvl_ifp->name,
+					 strlen(r->mvl_ifp->name));
+		}
+
+		if (ret < 0) {
+			zlog_warn(
+				VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				"Failed to bind Tx socket to macvlan device '%s'",
+				r->vr->vrid, family2str(r->family),
+				r->mvl_ifp->name);
+			failed = true;
+			goto done;
+		}
+	}
+	/* Configure sockets */
+	if (r->family == AF_INET) {
+		/* Set Tx socket to always Tx with TTL set to 255 */
+		int ttl = 255;
+
+		ret = setsockopt(r->sock_tx, IPPROTO_IP, IP_MULTICAST_TTL, &ttl,
+				 sizeof(ttl));
+		if (ret < 0) {
+			zlog_warn(
+				VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				"Failed to set outgoing multicast TTL count to 255; RFC 5798 compliant implementations will drop our packets",
+				r->vr->vrid, family2str(r->family));
+		}
+
+		/* Set Tx socket DSCP byte */
+		setsockopt_ipv4_tos(r->sock_tx, IPTOS_PREC_INTERNETCONTROL);
+
+		/* Turn off multicast loop on Tx */
+		setsockopt_ipv4_multicast_loop(r->sock_tx, 0);
+
+		/* Bind Rx socket to exact interface */
+		frr_with_privs(&vrrp_privs) {
+			ret = setsockopt(r->sock_rx, SOL_SOCKET,
+					 SO_BINDTODEVICE, r->vr->ifp->name,
+					 strlen(r->vr->ifp->name));
+		}
+		if (ret) {
+			zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				  "Failed to bind Rx socket to %s: %s",
+				  r->vr->vrid, family2str(r->family),
+				  r->vr->ifp->name, safe_strerror(errno));
+			failed = true;
+			goto done;
+		}
+		DEBUGD(&vrrp_dbg_sock,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Bound Rx socket to %s",
+		       r->vr->vrid, family2str(r->family), r->vr->ifp->name);
+
+		/* Bind Rx socket to v4 multicast address */
+		struct sockaddr_in sa = {0};
+
+		sa.sin_family = AF_INET;
+		sa.sin_addr.s_addr = htonl(VRRP_MCASTV4_GROUP);
+		if (bind(r->sock_rx, (struct sockaddr *)&sa, sizeof(sa))) {
+			zlog_err(
+				VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				"Failed to bind Rx socket to VRRP multicast group: %s",
+				r->vr->vrid, family2str(r->family),
+				safe_strerror(errno));
+			failed = true;
+			goto done;
+		}
+		DEBUGD(&vrrp_dbg_sock,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Bound Rx socket to VRRP multicast group",
+		       r->vr->vrid, family2str(r->family));
+
+		/* Join Rx socket to VRRP IPv4 multicast group */
+		assert(listhead(r->vr->ifp->connected));
+		struct connected *c = listhead(r->vr->ifp->connected)->data;
+		struct in_addr v4 = c->address->u.prefix4;
+
+		ret = setsockopt_ipv4_multicast(r->sock_rx, IP_ADD_MEMBERSHIP,
+						v4, htonl(VRRP_MCASTV4_GROUP),
+						r->vr->ifp->ifindex);
+		if (ret < 0) {
+			zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID
+				  "Failed to join VRRP %s multicast group",
+				  r->vr->vrid, family2str(r->family));
+			failed = true;
+			goto done;
+		}
+		DEBUGD(&vrrp_dbg_sock,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Joined VRRP multicast group",
+		       r->vr->vrid, family2str(r->family));
+
+		/* Set outgoing interface for advertisements */
+		struct ip_mreqn mreqn = {};
+
+		mreqn.imr_ifindex = r->mvl_ifp->ifindex;
+		ret = setsockopt(r->sock_tx, IPPROTO_IP, IP_MULTICAST_IF,
+				 (void *)&mreqn, sizeof(mreqn));
+		if (ret < 0) {
+			zlog_warn(
+				VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				"Could not set %s as outgoing multicast interface",
+				r->vr->vrid, family2str(r->family),
+				r->mvl_ifp->name);
+			failed = true;
+			goto done;
+		}
+		DEBUGD(&vrrp_dbg_sock,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Set %s as outgoing multicast interface",
+		       r->vr->vrid, family2str(r->family), r->mvl_ifp->name);
+
+		/* Select and bind source address */
+		if (vrrp_bind_to_primary_connected(r) < 0) {
+			failed = true;
+			goto done;
+		}
+
+	} else if (r->family == AF_INET6) {
+		/* Always transmit IPv6 packets with hop limit set to 255 */
+		ret = setsockopt_ipv6_multicast_hops(r->sock_tx, 255);
+		if (ret < 0) {
+			zlog_warn(
+				VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				"Failed to set outgoing multicast hop count to 255; RFC 5798 compliant implementations will drop our packets",
+				r->vr->vrid, family2str(r->family));
+		}
+
+		/* Set Tx socket DSCP byte */
+		setsockopt_ipv6_tclass(r->sock_tx, IPTOS_PREC_INTERNETCONTROL);
+
+		/* Request hop limit delivery */
+		setsockopt_ipv6_hoplimit(r->sock_rx, 1);
+		if (ret < 0) {
+			zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				  "Failed to request IPv6 Hop Limit delivery",
+				  r->vr->vrid, family2str(r->family));
+			failed = true;
+			goto done;
+		}
+
+		/* Turn off multicast loop on Tx */
+		setsockopt_ipv6_multicast_loop(r->sock_tx, 0);
+
+		/* Bind Rx socket to exact interface */
+		frr_with_privs(&vrrp_privs) {
+			ret = setsockopt(r->sock_rx, SOL_SOCKET,
+					 SO_BINDTODEVICE, r->vr->ifp->name,
+					 strlen(r->vr->ifp->name));
+		}
+		if (ret) {
+			zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				  "Failed to bind Rx socket to %s: %s",
+				  r->vr->vrid, family2str(r->family),
+				  r->vr->ifp->name, safe_strerror(errno));
+			failed = true;
+			goto done;
+		}
+		DEBUGD(&vrrp_dbg_sock,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Bound Rx socket to %s",
+		       r->vr->vrid, family2str(r->family), r->vr->ifp->name);
+
+		/* Bind Rx socket to v6 multicast address */
+		struct sockaddr_in6 sa = {0};
+
+		sa.sin6_family = AF_INET6;
+		inet_pton(AF_INET6, VRRP_MCASTV6_GROUP_STR, &sa.sin6_addr);
+		if (bind(r->sock_rx, (struct sockaddr *)&sa, sizeof(sa))) {
+			zlog_err(
+				VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				"Failed to bind Rx socket to VRRP multicast group: %s",
+				r->vr->vrid, family2str(r->family),
+				safe_strerror(errno));
+			failed = true;
+			goto done;
+		}
+		DEBUGD(&vrrp_dbg_sock,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Bound Rx socket to VRRP multicast group",
+		       r->vr->vrid, family2str(r->family));
+
+		/* Join VRRP IPv6 multicast group */
+		struct ipv6_mreq mreq;
+
+		inet_pton(AF_INET6, VRRP_MCASTV6_GROUP_STR,
+			  &mreq.ipv6mr_multiaddr);
+		mreq.ipv6mr_interface = r->vr->ifp->ifindex;
+		ret = setsockopt(r->sock_rx, IPPROTO_IPV6, IPV6_JOIN_GROUP,
+				 &mreq, sizeof(mreq));
+		if (ret < 0) {
+			zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				  "Failed to join VRRP multicast group",
+				  r->vr->vrid, family2str(r->family));
+			failed = true;
+			goto done;
+		}
+		DEBUGD(&vrrp_dbg_sock,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Joined VRRP multicast group",
+		       r->vr->vrid, family2str(r->family));
+
+		/* Set outgoing interface for advertisements */
+		ret = setsockopt(r->sock_tx, IPPROTO_IPV6, IPV6_MULTICAST_IF,
+				 &r->mvl_ifp->ifindex, sizeof(ifindex_t));
+		if (ret < 0) {
+			zlog_warn(
+				VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+				"Could not set %s as outgoing multicast interface",
+				r->vr->vrid, family2str(r->family),
+				r->mvl_ifp->name);
+			failed = true;
+			goto done;
+		}
+		DEBUGD(&vrrp_dbg_sock,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Set %s as outgoing multicast interface",
+		       r->vr->vrid, family2str(r->family), r->mvl_ifp->name);
+	}
+
+done:
+	ret = 0;
+	if (failed) {
+		zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "Failed to initialize VRRP router",
+			  r->vr->vrid, family2str(r->family));
+		if (r->sock_rx >= 0) {
+			close(r->sock_rx);
+			r->sock_rx = -1;
+		}
+		if (r->sock_tx >= 0) {
+			close(r->sock_tx);
+			r->sock_tx = -1;
+		}
+		ret = -1;
+	}
+
+	return ret;
+}
+
+
+/* State machine ----------------------------------------------------------- */
+
+DEFINE_HOOK(vrrp_change_state_hook, (struct vrrp_router *r, int to), (r, to));
+
+/*
+ * Handle any necessary actions during state change to MASTER state.
+ *
+ * r
+ *    VRRP Router to operate on
+ */
+static void vrrp_change_state_master(struct vrrp_router *r)
+{
+	/* Enable ND Router Advertisements */
+	if (r->family == AF_INET6)
+		vrrp_zebra_radv_set(r, true);
+
+	/* Set protodown off */
+	vrrp_zclient_send_interface_protodown(r->mvl_ifp, false);
+
+	/*
+	 * If protodown is already off, we can send our stuff, otherwise we
+	 * have to delay until the interface is all the way up
+	 */
+	if (if_is_operative(r->mvl_ifp)) {
+		vrrp_send_advertisement(r);
+
+		if (r->family == AF_INET)
+			vrrp_garp_send_all(r);
+		else if (r->family == AF_INET6)
+			vrrp_ndisc_una_send_all(r);
+	} else {
+		DEBUGD(&vrrp_dbg_proto,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Delaying VRRP advertisement until interface is up",
+		       r->vr->vrid, family2str(r->family));
+		r->advert_pending = true;
+
+		if (r->family == AF_INET) {
+			DEBUGD(&vrrp_dbg_proto,
+			       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			       "Delaying VRRP gratuitous ARPs until interface is up",
+			       r->vr->vrid, family2str(r->family));
+			r->garp_pending = true;
+		} else if (r->family == AF_INET6) {
+			DEBUGD(&vrrp_dbg_proto,
+			       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			       "Delaying VRRP unsolicited neighbor advertisement until interface is up",
+			       r->vr->vrid, family2str(r->family));
+			r->ndisc_pending = true;
+		}
+	}
+}
+
+/*
+ * Handle any necessary actions during state change to BACKUP state.
+ *
+ * r
+ *    Virtual Router to operate on
+ */
+static void vrrp_change_state_backup(struct vrrp_router *r)
+{
+	/* Disable ND Router Advertisements */
+	if (r->family == AF_INET6)
+		vrrp_zebra_radv_set(r, false);
+
+	/* Disable Adver_Timer */
+	THREAD_OFF(r->t_adver_timer);
+
+	r->advert_pending = false;
+	r->garp_pending = false;
+	r->ndisc_pending = false;
+	memset(&r->src, 0x00, sizeof(r->src));
+
+	vrrp_zclient_send_interface_protodown(r->mvl_ifp, true);
+}
+
+/*
+ * Handle any necessary actions during state change to INITIALIZE state.
+ *
+ * This is not called for initial startup, only when transitioning from MASTER
+ * or BACKUP.
+ *
+ * r
+ *    VRRP Router to operate on
+ */
+static void vrrp_change_state_initialize(struct vrrp_router *r)
+{
+	r->master_adver_interval = 0;
+	vrrp_recalculate_timers(r);
+
+	r->advert_pending = false;
+	r->garp_pending = false;
+	r->ndisc_pending = false;
+
+	/* Disable ND Router Advertisements */
+	if (r->family == AF_INET6 && r->mvl_ifp)
+		vrrp_zebra_radv_set(r, false);
+}
+
+void (*const vrrp_change_state_handlers[])(struct vrrp_router *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.
+ *
+ * r
+ *    Virtual Router for which to change state
+ *
+ * to
+ *    State to change to
+ */
+static void vrrp_change_state(struct vrrp_router *r, int to)
+{
+	if (r->fsm.state == to)
+		return;
+
+	/* Call our handlers, then any subscribers */
+	vrrp_change_state_handlers[to](r);
+	hook_call(vrrp_change_state_hook, r, to);
+	zlog_info(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM "%s -> %s",
+		  r->vr->vrid, family2str(r->family),
+		  vrrp_state_names[r->fsm.state], vrrp_state_names[to]);
+	r->fsm.state = to;
+
+	++r->stats.trans_cnt;
+}
+
+/*
+ * Called when Adver_Timer expires.
+ */
+static void vrrp_adver_timer_expire(struct thread *thread)
+{
+	struct vrrp_router *r = THREAD_ARG(thread);
+
+	DEBUGD(&vrrp_dbg_proto,
+	       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+	       "Adver_Timer expired",
+	       r->vr->vrid, family2str(r->family));
+
+	if (r->fsm.state == VRRP_STATE_MASTER) {
+		/* Send an ADVERTISEMENT */
+		vrrp_send_advertisement(r);
+
+		/* Reset the Adver_Timer to Advertisement_Interval */
+		thread_add_timer_msec(master, vrrp_adver_timer_expire, r,
+				      r->vr->advertisement_interval * CS2MS,
+				      &r->t_adver_timer);
+	} else {
+		zlog_err(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			 "Adver_Timer expired in state '%s'; this is a bug",
+			 r->vr->vrid, family2str(r->family),
+			 vrrp_state_names[r->fsm.state]);
+	}
+}
+
+/*
+ * Called when Master_Down_Timer expires.
+ */
+static void vrrp_master_down_timer_expire(struct thread *thread)
+{
+	struct vrrp_router *r = THREAD_ARG(thread);
+
+	zlog_info(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		  "Master_Down_Timer expired",
+		  r->vr->vrid, family2str(r->family));
+
+	thread_add_timer_msec(master, vrrp_adver_timer_expire, r,
+			      r->vr->advertisement_interval * CS2MS,
+			      &r->t_adver_timer);
+	vrrp_change_state(r, VRRP_STATE_MASTER);
+}
+
+/*
+ * Event handler for Startup event.
+ *
+ * Creates sockets, sends advertisements and ARP requests, starts timers,
+ * and transitions the Virtual Router to either Master or Backup states.
+ *
+ * This function will also initialize the program's global ARP subsystem if it
+ * has not yet been initialized.
+ *
+ * r
+ *    VRRP Router on which to apply Startup event
+ *
+ * Returns:
+ *    < 0 if the session socket could not be created, or the state is not
+ *        Initialize
+ *      0 on success
+ */
+static int vrrp_startup(struct vrrp_router *r)
+{
+	/* May only be called when the state is Initialize */
+	if (r->fsm.state != VRRP_STATE_INITIALIZE)
+		return -1;
+
+	/* Must have a valid macvlan interface available */
+	if (r->mvl_ifp == NULL && !vrrp_attach_interface(r)) {
+		zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "No appropriate interface found",
+			  r->vr->vrid, family2str(r->family));
+		return -1;
+	}
+
+	/* Initialize global gratuitous ARP socket if necessary */
+	if (r->family == AF_INET && !vrrp_garp_is_init())
+		vrrp_garp_init();
+	if (r->family == AF_INET6 && !vrrp_ndisc_is_init())
+		vrrp_ndisc_init();
+
+	/* Create socket */
+	if (r->sock_rx < 0 || r->sock_tx < 0) {
+		int ret = vrrp_socket(r);
+
+		if (ret < 0 || r->sock_tx < 0 || r->sock_rx < 0)
+			return ret;
+	}
+
+	/* Schedule listener */
+	thread_add_read(master, vrrp_read, r, r->sock_rx, &r->t_read);
+
+	/* Configure effective priority */
+	assert(listhead(r->addrs));
+	struct ipaddr *primary = (struct ipaddr *)listhead(r->addrs)->data;
+	char ipbuf[INET6_ADDRSTRLEN];
+
+	inet_ntop(r->family, &primary->ip.addr, ipbuf, sizeof(ipbuf));
+
+	if (r->vr->priority == VRRP_PRIO_MASTER
+	    || vrrp_is_owner(r->vr->ifp, primary)) {
+		r->priority = VRRP_PRIO_MASTER;
+		vrrp_recalculate_timers(r);
+
+		zlog_info(
+			VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			"%s has priority set to 255 or owns primary Virtual Router IP %s; electing self as Master",
+			r->vr->vrid, family2str(r->family), r->vr->ifp->name,
+			ipbuf);
+	}
+
+	if (r->priority == VRRP_PRIO_MASTER) {
+		thread_add_timer_msec(master, vrrp_adver_timer_expire, r,
+				      r->vr->advertisement_interval * CS2MS,
+				      &r->t_adver_timer);
+		vrrp_change_state(r, VRRP_STATE_MASTER);
+	} else {
+		r->master_adver_interval = r->vr->advertisement_interval;
+		vrrp_recalculate_timers(r);
+		thread_add_timer_msec(master, vrrp_master_down_timer_expire, r,
+				      r->master_down_interval * CS2MS,
+				      &r->t_master_down_timer);
+		vrrp_change_state(r, VRRP_STATE_BACKUP);
+	}
+
+	r->is_active = true;
+
+	return 0;
+}
+
+/*
+ * Shuts down a Virtual Router and transitions it to Initialize.
+ *
+ * This call must be idempotent; it is safe to call multiple times on the same
+ * VRRP Router.
+ */
+static int vrrp_shutdown(struct vrrp_router *r)
+{
+	uint8_t saved_prio;
+
+	switch (r->fsm.state) {
+	case VRRP_STATE_MASTER:
+		/* Send an ADVERTISEMENT with Priority = 0 */
+		saved_prio = r->priority;
+		r->priority = 0;
+		vrrp_send_advertisement(r);
+		r->priority = saved_prio;
+		break;
+	case VRRP_STATE_BACKUP:
+		break;
+	case VRRP_STATE_INITIALIZE:
+		DEBUGD(&vrrp_dbg_proto,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Received '%s' event in '%s' state; ignoring",
+		       r->vr->vrid, family2str(r->family),
+		       vrrp_event_names[VRRP_EVENT_SHUTDOWN],
+		       vrrp_state_names[VRRP_STATE_INITIALIZE]);
+		return 0;
+	}
+
+	/* Cancel all timers */
+	THREAD_OFF(r->t_adver_timer);
+	THREAD_OFF(r->t_master_down_timer);
+	THREAD_OFF(r->t_read);
+	THREAD_OFF(r->t_write);
+
+	/* Protodown macvlan */
+	if (r->mvl_ifp)
+		vrrp_zclient_send_interface_protodown(r->mvl_ifp, true);
+
+	/* Throw away our source address */
+	memset(&r->src, 0x00, sizeof(r->src));
+
+	if (r->sock_rx > 0) {
+		close(r->sock_rx);
+		r->sock_rx = -1;
+	}
+	if (r->sock_tx > 0) {
+		close(r->sock_tx);
+		r->sock_tx = -1;
+	}
+
+	vrrp_change_state(r, VRRP_STATE_INITIALIZE);
+
+	r->is_active = false;
+
+	return 0;
+}
+
+static int (*const vrrp_event_handlers[])(struct vrrp_router *r) = {
+	[VRRP_EVENT_STARTUP] = vrrp_startup,
+	[VRRP_EVENT_SHUTDOWN] = vrrp_shutdown,
+};
+
+/*
+ * Spawn a VRRP FSM event on a VRRP Router.
+ *
+ * vr
+ *    VRRP Router on which to spawn event
+ *
+ * event
+ *    The event to spawn
+ *
+ * Returns:
+ *    -1 on failure
+ *     0 otherwise
+ */
+int vrrp_event(struct vrrp_router *r, int event)
+{
+	zlog_info(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM "'%s' event",
+		  r->vr->vrid, family2str(r->family), vrrp_event_names[event]);
+	return vrrp_event_handlers[event](r);
+}
+
+
+/* Autoconfig -------------------------------------------------------------- */
+
+/*
+ * Set the configured addresses for this VRRP instance to exactly the addresses
+ * present on its macvlan subinterface(s).
+ *
+ * vr
+ *    VRRP router to act on
+ */
+static void vrrp_autoconfig_autoaddrupdate(struct vrrp_router *r)
+{
+	struct listnode *ln;
+	struct connected *c = NULL;
+	bool is_v6_ll;
+
+	if (!r->mvl_ifp)
+		return;
+
+	DEBUGD(&vrrp_dbg_auto,
+	       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+	       "Setting Virtual IP list to match IPv4 addresses on %s",
+	       r->vr->vrid, family2str(r->family), r->mvl_ifp->name);
+	for (ALL_LIST_ELEMENTS_RO(r->mvl_ifp->connected, ln, c)) {
+		is_v6_ll = (c->address->family == AF_INET6
+			    && IN6_IS_ADDR_LINKLOCAL(&c->address->u.prefix6));
+		if (c->address->family == r->family && !is_v6_ll) {
+			DEBUGD(&vrrp_dbg_auto,
+			       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			       "Adding %pFX",
+			       r->vr->vrid, family2str(r->family), c->address);
+			if (r->family == AF_INET)
+				vrrp_add_ipv4(r->vr, c->address->u.prefix4);
+			else if (r->vr->version == 3)
+				vrrp_add_ipv6(r->vr, c->address->u.prefix6);
+		}
+	}
+
+	vrrp_check_start(r->vr);
+
+	if (r->addrs->count == 0 && r->fsm.state != VRRP_STATE_INITIALIZE) {
+		DEBUGD(&vrrp_dbg_auto,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+		       "Virtual IP list is empty; shutting down",
+		       r->vr->vrid, family2str(r->family));
+		vrrp_event(r, VRRP_EVENT_SHUTDOWN);
+	}
+}
+
+static struct vrrp_vrouter *
+vrrp_autoconfig_autocreate(struct interface *mvl_ifp)
+{
+	struct interface *p;
+	struct vrrp_vrouter *vr;
+
+	p = if_lookup_by_index(mvl_ifp->link_ifindex, mvl_ifp->vrf->vrf_id);
+
+	if (!p)
+		return NULL;
+
+	uint8_t vrid = mvl_ifp->hw_addr[5];
+	uint8_t fam = mvl_ifp->hw_addr[4];
+
+	DEBUGD(&vrrp_dbg_auto,
+	       VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+	       "Autoconfiguring VRRP on %s",
+	       vrid, family2str(fam), p->name);
+
+	vr = vrrp_vrouter_create(p, vrid, vrrp_autoconfig_version);
+
+	if (!vr) {
+		zlog_warn(VRRP_LOGPFX VRRP_LOGPFX_VRID VRRP_LOGPFX_FAM
+			  "Failed to autoconfigure VRRP on %s",
+			  vrid, family2str(fam), p->name);
+		return NULL;
+	}
+
+	vr->autoconf = true;
+
+	/*
+	 * If these interfaces are protodown on, we need to un-protodown them
+	 * in order to get Zebra to send us their addresses so we can
+	 * autoconfigure them.
+	 */
+	if (vr->v4->mvl_ifp)
+		vrrp_zclient_send_interface_protodown(vr->v4->mvl_ifp, false);
+	if (vr->v6->mvl_ifp)
+		vrrp_zclient_send_interface_protodown(vr->v6->mvl_ifp, false);
+
+	 /* If they're not, we can go ahead and add the addresses we have */
+	vrrp_autoconfig_autoaddrupdate(vr->v4);
+	vrrp_autoconfig_autoaddrupdate(vr->v6);
+
+	return vr;
+}
+
+/*
+ * Callback to notify autoconfig of interface add.
+ *
+ * If the interface is a VRRP-compatible device, and there is no existing VRRP
+ * router running on it, one is created. All addresses on the interface are
+ * added to the router.
+ *
+ * ifp
+ *    Interface to operate on
+ *
+ * Returns:
+ *    -1 on failure
+ *     0 otherwise
+ */
+static int vrrp_autoconfig_if_add(struct interface *ifp)
+{
+	bool created = false;
+	struct vrrp_vrouter *vr;
+
+	if (!vrrp_autoconfig_is_on)
+		return 0;
+
+	if (!ifp || !ifp->link_ifindex || !vrrp_ifp_has_vrrp_mac(ifp))
+		return -1;
+
+	vr = vrrp_lookup_by_if_mvl(ifp);
+
+	if (!vr) {
+		vr = vrrp_autoconfig_autocreate(ifp);
+		created = true;
+	}
+
+	if (!vr || !vr->autoconf)
+		return 0;
+
+	if (!created) {
+		/*
+		 * We didn't create it, but it has already been autoconfigured.
+		 * Try to attach this interface to the existing instance.
+		 */
+		if (!vr->v4->mvl_ifp) {
+			vrrp_attach_interface(vr->v4);
+			/* If we just attached it, make sure it's turned on */
+			if (vr->v4->mvl_ifp) {
+				vrrp_zclient_send_interface_protodown(
+					vr->v4->mvl_ifp, false);
+				/*
+				 * If it's already up, we can go ahead and add
+				 * the addresses we have
+				 */
+				vrrp_autoconfig_autoaddrupdate(vr->v4);
+			}
+		}
+		if (!vr->v6->mvl_ifp) {
+			vrrp_attach_interface(vr->v6);
+			/* If we just attached it, make sure it's turned on */
+			if (vr->v6->mvl_ifp) {
+				vrrp_zclient_send_interface_protodown(
+					vr->v6->mvl_ifp, false);
+				/*
+				 * If it's already up, we can go ahead and add
+				 * the addresses we have
+				 */
+				vrrp_autoconfig_autoaddrupdate(vr->v6);
+			}
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Callback to notify autoconfig of interface delete.
+ *
+ * If the interface is a VRRP-compatible device, and a VRRP router is running
+ * on it, and that VRRP router was automatically configured, it will be
+ * deleted. If that was the last router for the corresponding VRID (i.e., if
+ * this interface was a v4 VRRP interface and no v6 router is configured for
+ * the same VRID) then the entire virtual router is deleted.
+ *
+ * ifp
+ *    Interface to operate on
+ *
+ * Returns:
+ *    -1 on failure
+ *     0 otherwise
+ */
+static int vrrp_autoconfig_if_del(struct interface *ifp)
+{
+	if (!vrrp_autoconfig_is_on)
+		return 0;
+
+	struct vrrp_vrouter *vr;
+	struct listnode *ln;
+	struct list *vrs;
+
+	vrs = vrrp_lookup_by_if_any(ifp);
+
+	for (ALL_LIST_ELEMENTS_RO(vrs, ln, vr))
+		if (vr->autoconf
+		    && (!vr->ifp || (!vr->v4->mvl_ifp && !vr->v6->mvl_ifp))) {
+			DEBUGD(&vrrp_dbg_auto,
+			       VRRP_LOGPFX VRRP_LOGPFX_VRID
+			       "All VRRP interfaces for instance deleted; destroying autoconfigured VRRP router",
+			       vr->vrid);
+			vrrp_vrouter_destroy(vr);
+		}
+
+	list_delete(&vrs);
+
+	return 0;
+}
+
+/*
+ * Callback to notify autoconfig of interface up.
+ *
+ * Creates VRRP instance on interface if it does not exist. Otherwise does
+ * nothing.
+ *
+ * ifp
+ *    Interface to operate on
+ *
+ * Returns:
+ *    -1 on failure
+ *     0 otherwise
+ */
+static int vrrp_autoconfig_if_up(struct interface *ifp)
+{
+	if (!vrrp_autoconfig_is_on)
+		return 0;
+
+	struct vrrp_vrouter *vr = vrrp_lookup_by_if_mvl(ifp);
+
+	if (vr && !vr->autoconf)
+		return 0;
+
+	if (!vr) {
+		vrrp_autoconfig_if_add(ifp);
+		return 0;
+	}
+
+	return 0;
+}
+
+/*
+ * Callback to notify autoconfig of interface down.
+ *
+ * Does nothing. An interface down event is accompanied by address deletion
+ * events for all the addresses on the interface; if an autoconfigured VRRP
+ * router exists on this interface, then it will have all its addresses deleted
+ * and end up in Initialize.
+ *
+ * ifp
+ *    Interface to operate on
+ *
+ * Returns:
+ *    -1 on failure
+ *     0 otherwise
+ */
+static int vrrp_autoconfig_if_down(struct interface *ifp)
+{
+	if (!vrrp_autoconfig_is_on)
+		return 0;
+
+	return 0;
+}
+
+/*
+ * Callback to notify autoconfig of a new interface address.
+ *
+ * If a VRRP router exists on this interface, its address list is updated to
+ * match the new address list. If no addresses remain, a Shutdown event is
+ * issued to the VRRP router.
+ *
+ * ifp
+ *    Interface to operate on
+ *
+ * Returns:
+ *    -1 on failure
+ *     0 otherwise
+ *
+ */
+static int vrrp_autoconfig_if_address_add(struct interface *ifp)
+{
+	if (!vrrp_autoconfig_is_on)
+		return 0;
+
+	struct vrrp_vrouter *vr = vrrp_lookup_by_if_mvl(ifp);
+
+	if (vr && vr->autoconf) {
+		if (vr->v4->mvl_ifp == ifp)
+			vrrp_autoconfig_autoaddrupdate(vr->v4);
+		else if (vr->v6->mvl_ifp == ifp)
+			vrrp_autoconfig_autoaddrupdate(vr->v6);
+	}
+
+	return 0;
+}
+
+/*
+ * Callback to notify autoconfig of a removed interface address.
+ *
+ * If a VRRP router exists on this interface, its address list is updated to
+ * match the new address list. If no addresses remain, a Shutdown event is
+ * issued to the VRRP router.
+ *
+ * ifp
+ *    Interface to operate on
+ *
+ * Returns:
+ *    -1 on failure
+ *     0 otherwise
+ *
+ */
+static int vrrp_autoconfig_if_address_del(struct interface *ifp)
+{
+	if (!vrrp_autoconfig_is_on)
+		return 0;
+
+	struct vrrp_vrouter *vr = vrrp_lookup_by_if_mvl(ifp);
+
+	if (vr && vr->autoconf) {
+		if (vr->v4->mvl_ifp == ifp)
+			vrrp_autoconfig_autoaddrupdate(vr->v4);
+		else if (vr->v6->mvl_ifp == ifp)
+			vrrp_autoconfig_autoaddrupdate(vr->v6);
+	}
+
+	return 0;
+}
+
+int vrrp_autoconfig(void)
+{
+	if (!vrrp_autoconfig_is_on)
+		return 0;
+
+	struct vrf *vrf;
+	struct interface *ifp;
+
+	RB_FOREACH (vrf, vrf_name_head, &vrfs_by_name) {
+		FOR_ALL_INTERFACES (vrf, ifp)
+			vrrp_autoconfig_if_add(ifp);
+	}
+
+	return 0;
+}
+
+void vrrp_autoconfig_on(int version)
+{
+	vrrp_autoconfig_is_on = true;
+	vrrp_autoconfig_version = version;
+
+	vrrp_autoconfig();
+}
+
+void vrrp_autoconfig_off(void)
+{
+	vrrp_autoconfig_is_on = false;
+
+	struct list *ll = hash_to_list(vrrp_vrouters_hash);
+
+	struct listnode *ln;
+	struct vrrp_vrouter *vr;
+
+	for (ALL_LIST_ELEMENTS_RO(ll, ln, vr))
+		if (vr->autoconf)
+			vrrp_vrouter_destroy(vr);
+
+	list_delete(&ll);
+}
+
+/* Interface tracking ------------------------------------------------------ */
+
+/*
+ * Bind any pending interfaces.
+ *
+ * mvl_ifp
+ *    macvlan interface that some VRRP instances might want to bind to
+ */
+static void vrrp_bind_pending(struct interface *mvl_ifp)
+{
+	struct vrrp_vrouter *vr;
+
+	DEBUGD(&vrrp_dbg_zebra,
+	       VRRP_LOGPFX
+	       "Searching for instances that could use interface %s",
+	       mvl_ifp->name);
+
+	vr = vrrp_lookup_by_if_mvl(mvl_ifp);
+
+	if (vr) {
+		DEBUGD(&vrrp_dbg_zebra,
+		       VRRP_LOGPFX VRRP_LOGPFX_VRID
+		       "<-- This instance can probably use interface %s",
+		       vr->vrid, mvl_ifp->name);
+
+		if (mvl_ifp->hw_addr[4] == 0x01 && !vr->v4->mvl_ifp)
+			vrrp_attach_interface(vr->v4);
+		else if (mvl_ifp->hw_addr[4] == 0x02 && !vr->v6->mvl_ifp)
+			vrrp_attach_interface(vr->v6);
+	}
+}
+
+void vrrp_if_up(struct interface *ifp)
+{
+	struct vrrp_vrouter *vr;
+	struct listnode *ln;
+	struct list *vrs;
+
+	vrrp_bind_pending(ifp);
+
+	vrs = vrrp_lookup_by_if_any(ifp);
+
+	for (ALL_LIST_ELEMENTS_RO(vrs, ln, vr)) {
+		vrrp_check_start(vr);
+
+		if (!if_is_operative(ifp))
+			continue;
+
+		/*
+		 * Handle the situation in which we performed a state
+		 * transition on this VRRP router but needed to wait for the
+		 * macvlan interface to come up to perform some actions
+		 */
+		if (ifp == vr->v4->mvl_ifp) {
+			if (vr->v4->advert_pending) {
+				DEBUGD(&vrrp_dbg_proto,
+				       VRRP_LOGPFX VRRP_LOGPFX_VRID
+					       VRRP_LOGPFX_FAM
+				       "Interface up; sending pending advertisement",
+				       vr->vrid, family2str(vr->v4->family));
+				vrrp_send_advertisement(vr->v4);
+				vr->v4->advert_pending = false;
+			}
+			if (vr->v4->garp_pending) {
+				DEBUGD(&vrrp_dbg_proto,
+				       VRRP_LOGPFX VRRP_LOGPFX_VRID
+					       VRRP_LOGPFX_FAM
+				       "Interface up; sending pending gratuitous ARP",
+				       vr->vrid, family2str(vr->v4->family));
+				vrrp_garp_send_all(vr->v4);
+				vr->v4->garp_pending = false;
+			}
+		}
+		if (ifp == vr->v6->mvl_ifp) {
+			if (vr->v6->advert_pending) {
+				DEBUGD(&vrrp_dbg_proto,
+				       VRRP_LOGPFX VRRP_LOGPFX_VRID
+					       VRRP_LOGPFX_FAM
+				       "Interface up; sending pending advertisement",
+				       vr->vrid, family2str(vr->v6->family));
+				vrrp_send_advertisement(vr->v6);
+				vr->v6->advert_pending = false;
+			}
+			if (vr->v6->ndisc_pending) {
+				DEBUGD(&vrrp_dbg_proto,
+				       VRRP_LOGPFX VRRP_LOGPFX_VRID
+					       VRRP_LOGPFX_FAM
+				       "Interface up; sending pending Unsolicited Neighbor Advertisement",
+				       vr->vrid, family2str(vr->v6->family));
+				vrrp_ndisc_una_send_all(vr->v6);
+				vr->v6->ndisc_pending = false;
+			}
+		}
+	}
+
+	list_delete(&vrs);
+
+	vrrp_autoconfig_if_up(ifp);
+}
+
+void vrrp_if_down(struct interface *ifp)
+{
+	struct vrrp_vrouter *vr;
+	struct listnode *ln;
+	struct list *vrs;
+
+	vrrp_bind_pending(ifp);
+
+	vrs = vrrp_lookup_by_if_any(ifp);
+
+	for (ALL_LIST_ELEMENTS_RO(vrs, ln, vr)) {
+		vrrp_check_start(vr);
+
+		if (vr->ifp == ifp || vr->v4->mvl_ifp == ifp
+		    || vr->v6->mvl_ifp == ifp) {
+			DEBUGD(&vrrp_dbg_auto,
+			       VRRP_LOGPFX VRRP_LOGPFX_VRID "Interface %s down",
+			       vr->vrid, ifp->name);
+		}
+	}
+
+	list_delete(&vrs);
+
+	vrrp_autoconfig_if_down(ifp);
+}
+
+void vrrp_if_add(struct interface *ifp)
+{
+	vrrp_bind_pending(ifp);
+
+	/* thanks, zebra */
+	if (CHECK_FLAG(ifp->flags, IFF_UP))
+		vrrp_if_up(ifp);
+
+	vrrp_autoconfig_if_add(ifp);
+}
+
+void vrrp_if_del(struct interface *ifp)
+{
+	struct listnode *ln;
+	struct vrrp_vrouter *vr;
+
+	vrrp_if_down(ifp);
+
+	/*
+	 * You think we'd be able use vrrp_lookup_by_if_any to find interfaces?
+	 * Nah. FRR's interface management is insane. There are no ordering
+	 * guarantees about what interfaces are deleted when. Maybe this is a
+	 * macvlan and its parent was already deleted, in which case its
+	 * ifindex is now IFINDEX_INTERNAL, so ifp->link_ifindex - while still
+	 * valid - doesn't match any interface on the system, meaning we can't
+	 * use any of the vrrp_lookup* functions since they rely on finding the
+	 * base interface of what they're given by following link_ifindex.
+	 *
+	 * Since we need to actually NULL out pointers in this function to
+	 * avoid a UAF - since the caller will (might) free ifp after we return
+	 * - we need to look up based on pointers.
+	 */
+	struct list *vrs = hash_to_list(vrrp_vrouters_hash);
+
+	for (ALL_LIST_ELEMENTS_RO(vrs, ln, vr)) {
+		if (ifp == vr->ifp) {
+			vrrp_event(vr->v4, VRRP_EVENT_SHUTDOWN);
+			vrrp_event(vr->v6, VRRP_EVENT_SHUTDOWN);
+			/*
+			 * Stands to reason if the base was deleted, so were
+			 * (or will be) its children
+			 */
+			vr->v4->mvl_ifp = NULL;
+			vr->v6->mvl_ifp = NULL;
+			/*
+			 * We shouldn't need to lose the reference if it's the
+			 * primary interface, because that was configured
+			 * explicitly in our config, and thus will be kept as a
+			 * stub; to avoid stupid bugs, double check that
+			 */
+			assert(ifp->configured);
+		} else if (ifp == vr->v4->mvl_ifp) {
+			vrrp_event(vr->v4, VRRP_EVENT_SHUTDOWN);
+			/*
+			 * If this is a macvlan, then it wasn't explicitly
+			 * configured and will be deleted when we return from
+			 * this function, so we need to lose the reference
+			 */
+			vr->v4->mvl_ifp = NULL;
+		} else if (ifp == vr->v6->mvl_ifp) {
+			vrrp_event(vr->v6, VRRP_EVENT_SHUTDOWN);
+			/*
+			 * If this is a macvlan, then it wasn't explicitly
+			 * configured and will be deleted when we return from
+			 * this function, so we need to lose the reference
+			 */
+			vr->v6->mvl_ifp = NULL;
+		}
+	}
+
+	list_delete(&vrs);
+
+	vrrp_autoconfig_if_del(ifp);
+}
+
+void vrrp_if_address_add(struct interface *ifp)
+{
+	struct vrrp_vrouter *vr;
+	struct listnode *ln;
+	struct list *vrs;
+
+	/*
+	 * We have to do a wide search here, because we need to know when a v6
+	 * macvlan device gets a new address. This is because the macvlan link
+	 * local is used as the source address for v6 advertisements, and hence
+	 * "do I have a link local" constitutes an activation condition for v6
+	 * virtual routers.
+	 */
+	vrs = vrrp_lookup_by_if_any(ifp);
+
+	for (ALL_LIST_ELEMENTS_RO(vrs, ln, vr))
+		vrrp_check_start(vr);
+
+	list_delete(&vrs);
+
+	vrrp_autoconfig_if_address_add(ifp);
+}
+
+void vrrp_if_address_del(struct interface *ifp)
+{
+	/*
+	 * Zebra is stupid and sends us address deletion notifications
+	 * when any of the following condition sets are met:
+	 *
+	 * - if_is_operative && address deleted
+	 * - if_is_operative -> !if_is_operative
+	 *
+	 * Note that the second one is nonsense, because Zebra behaves as
+	 * though an interface going down means all the addresses on that
+	 * interface got deleted. Which is a problem for autoconfig because all
+	 * the addresses on an interface going away means the VRRP session goes
+	 * to Initialize. However interfaces go down whenever we transition to
+	 * Backup, so this effectively means that for autoconfigured instances
+	 * we actually end up in Initialize whenever we try to go into Backup.
+	 *
+	 * Also, Zebra does NOT send us notifications when:
+	 * - !if_is_operative && address deleted
+	 *
+	 * Which means if we're in backup and an address is deleted out from
+	 * under us, we won't even know.
+	 *
+	 * The only solution here is to only resynchronize our address list
+	 * when:
+	 *
+	 * - An interfaces comes up
+	 * - An interface address is added
+	 * - An interface address is deleted AND the interface is up
+	 *
+	 * Even though this is only a problem with autoconfig at the moment I'm
+	 * papering over Zebra's braindead semantics here. Every piece of code
+	 * in this function should be protected by a check that the interface
+	 * is up.
+	 */
+	if (if_is_operative(ifp))
+		vrrp_autoconfig_if_address_del(ifp);
+}
+
+/* Other ------------------------------------------------------------------- */
+
+int vrrp_config_write_global(struct vty *vty)
+{
+	unsigned int writes = 0;
+
+	if (vrrp_autoconfig_is_on && ++writes)
+		vty_out(vty, "vrrp autoconfigure%s\n",
+			vrrp_autoconfig_version == 2 ? " version 2" : "");
+
+	/* FIXME: needs to be udpated for full YANG conversion. */
+	if (vd.priority != VRRP_DEFAULT_PRIORITY && ++writes)
+		vty_out(vty, "vrrp default priority %hhu\n", vd.priority);
+
+	if (vd.advertisement_interval != VRRP_DEFAULT_ADVINT && ++writes)
+		vty_out(vty,
+			"vrrp default advertisement-interval %u\n",
+			vd.advertisement_interval * CS2MS);
+
+	if (vd.preempt_mode != VRRP_DEFAULT_PREEMPT && ++writes)
+		vty_out(vty, "%svrrp default preempt\n",
+			!vd.preempt_mode ? "no " : "");
+
+	if (vd.accept_mode != VRRP_DEFAULT_ACCEPT && ++writes)
+		vty_out(vty, "%svrrp default accept\n",
+			!vd.accept_mode ? "no " : "");
+
+	if (vd.shutdown != VRRP_DEFAULT_SHUTDOWN && ++writes)
+		vty_out(vty, "%svrrp default shutdown\n",
+			!vd.shutdown ? "no " : "");
+
+	return writes;
+}
+
+static unsigned int vrrp_hash_key(const void *arg)
+{
+	const struct vrrp_vrouter *vr = arg;
+	char key[IFNAMSIZ + 64];
+
+	snprintf(key, sizeof(key), "%s@%u", vr->ifp->name, vr->vrid);
+
+	return string_hash_make(key);
+}
+
+static bool vrrp_hash_cmp(const void *arg1, const void *arg2)
+{
+	const struct vrrp_vrouter *vr1 = arg1;
+	const struct vrrp_vrouter *vr2 = arg2;
+
+	if (vr1->ifp != vr2->ifp)
+		return false;
+	if (vr1->vrid != vr2->vrid)
+		return false;
+
+	return true;
+}
+
+void vrrp_init(void)
+{
+	/* Set default defaults */
+	vd.version = yang_get_default_uint8("%s/version", VRRP_XPATH_FULL);
+	vd.priority = yang_get_default_uint8("%s/priority", VRRP_XPATH_FULL);
+	vd.advertisement_interval = yang_get_default_uint16(
+		"%s/advertisement-interval", VRRP_XPATH_FULL);
+	vd.preempt_mode = yang_get_default_bool("%s/preempt", VRRP_XPATH_FULL);
+	vd.accept_mode =
+		yang_get_default_bool("%s/accept-mode", VRRP_XPATH_FULL);
+	vd.shutdown = VRRP_DEFAULT_SHUTDOWN;
+
+	vrrp_autoconfig_version = 3;
+	vrrp_vrouters_hash = hash_create(&vrrp_hash_key, vrrp_hash_cmp,
+					 "VRRP virtual router hash");
+	vrf_init(NULL, NULL, NULL, NULL);
+}
+
+void vrrp_fini(void)
+{
+	/* Destroy all instances */
+	struct list *vrs = hash_to_list(vrrp_vrouters_hash);
+
+	struct listnode *ln;
+	struct vrrp_vrouter *vr;
+
+	for (ALL_LIST_ELEMENTS_RO(vrs, ln, vr))
+		vrrp_vrouter_destroy(vr);
+
+	list_delete(&vrs);
+
+	hash_clean(vrrp_vrouters_hash, NULL);
+	hash_free(vrrp_vrouters_hash);
+}