[mirror_frr.git] / pimd / pim_upstream.c

/*
 * PIM for Quagga
 * Copyright (C) 2008  Everton da Silva Marques
 *
 * 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 "zebra/rib.h"

#include "log.h"
#include "zclient.h"
#include "memory.h"
#include "thread.h"
#include "linklist.h"
#include "vty.h"
#include "plist.h"
#include "hash.h"
#include "jhash.h"
#include "wheel.h"

#include "pimd.h"
#include "pim_pim.h"
#include "pim_str.h"
#include "pim_time.h"
#include "pim_iface.h"
#include "pim_join.h"
#include "pim_zlookup.h"
#include "pim_upstream.h"
#include "pim_ifchannel.h"
#include "pim_neighbor.h"
#include "pim_rpf.h"
#include "pim_zebra.h"
#include "pim_oil.h"
#include "pim_macro.h"
#include "pim_rp.h"
#include "pim_br.h"
#include "pim_register.h"
#include "pim_msdp.h"
#include "pim_jp_agg.h"
#include "pim_nht.h"
#include "pim_ssm.h"

static void join_timer_stop(struct pim_upstream *up);
static void
pim_upstream_update_assert_tracking_desired(struct pim_upstream *up);

/*
 * A (*,G) or a (*,*) is going away
 * remove the parent pointer from
 * those pointing at us
 */
static void pim_upstream_remove_children(struct pim_instance *pim,
					 struct pim_upstream *up)
{
	struct pim_upstream *child;

	if (!up->sources)
		return;

	while (!list_isempty(up->sources)) {
		child = listnode_head(up->sources);
		listnode_delete(up->sources, child);
		if (PIM_UPSTREAM_FLAG_TEST_SRC_LHR(child->flags)) {
			PIM_UPSTREAM_FLAG_UNSET_SRC_LHR(child->flags);
			child = pim_upstream_del(pim, child,
						 __PRETTY_FUNCTION__);
		}
		if (child)
			child->parent = NULL;
	}
	list_delete(up->sources);
	up->sources = NULL;
}

/*
 * A (*,G) or a (*,*) is being created
 * Find the children that would point
 * at us.
 */
static void pim_upstream_find_new_children(struct pim_instance *pim,
					   struct pim_upstream *up)
{
	struct pim_upstream *child;
	struct listnode *ch_node;

	if ((up->sg.src.s_addr != INADDR_ANY)
	    && (up->sg.grp.s_addr != INADDR_ANY))
		return;

	if ((up->sg.src.s_addr == INADDR_ANY)
	    && (up->sg.grp.s_addr == INADDR_ANY))
		return;

	for (ALL_LIST_ELEMENTS_RO(pim->upstream_list, ch_node, child)) {
		if ((up->sg.grp.s_addr != INADDR_ANY)
		    && (child->sg.grp.s_addr == up->sg.grp.s_addr)
		    && (child != up)) {
			child->parent = up;
			listnode_add_sort(up->sources, child);
		}
	}
}

/*
 * If we have a (*,*) || (S,*) there is no parent
 * If we have a (S,G), find the (*,G)
 * If we have a (*,G), find the (*,*)
 */
static struct pim_upstream *pim_upstream_find_parent(struct pim_instance *pim,
						     struct pim_upstream *child)
{
	struct prefix_sg any = child->sg;
	struct pim_upstream *up = NULL;

	// (S,G)
	if ((child->sg.src.s_addr != INADDR_ANY)
	    && (child->sg.grp.s_addr != INADDR_ANY)) {
		any.src.s_addr = INADDR_ANY;
		up = pim_upstream_find(pim, &any);

		if (up)
			listnode_add(up->sources, child);

		return up;
	}

	return NULL;
}

void pim_upstream_free(struct pim_upstream *up)
{
	XFREE(MTYPE_PIM_UPSTREAM, up);
	up = NULL;
}

static void upstream_channel_oil_detach(struct pim_upstream *up)
{
	if (up->channel_oil) {
		/* Detaching from channel_oil, channel_oil may exist post del,
		   but upstream would not keep reference of it
		 */
		pim_channel_oil_del(up->channel_oil);
		up->channel_oil = NULL;
	}
}

struct pim_upstream *pim_upstream_del(struct pim_instance *pim,
				      struct pim_upstream *up, const char *name)
{
	bool notify_msdp = false;
	struct prefix nht_p;

	if (PIM_DEBUG_TRACE)
		zlog_debug(
			"%s(%s): Delete %s ref count: %d , flags: %d c_oil ref count %d (Pre decrement)",
			__PRETTY_FUNCTION__, name, up->sg_str, up->ref_count,
			up->flags, up->channel_oil->oil_ref_count);

	--up->ref_count;

	if (up->ref_count >= 1)
		return up;

	THREAD_OFF(up->t_ka_timer);
	THREAD_OFF(up->t_rs_timer);
	THREAD_OFF(up->t_msdp_reg_timer);

	if (up->join_state == PIM_UPSTREAM_JOINED) {
		pim_jp_agg_single_upstream_send(&up->rpf, up, 0);

		if (up->sg.src.s_addr == INADDR_ANY) {
			/* if a (*, G) entry in the joined state is being
			 * deleted we
			 * need to notify MSDP */
			notify_msdp = true;
		}
	}

	join_timer_stop(up);
	pim_jp_agg_upstream_verification(up, false);
	up->rpf.source_nexthop.interface = NULL;

	if (up->sg.src.s_addr != INADDR_ANY) {
		wheel_remove_item(pim->upstream_sg_wheel, up);
		notify_msdp = true;
	}

	pim_upstream_remove_children(pim, up);
	if (up->sources)
		list_delete(up->sources);
	up->sources = NULL;
	pim_mroute_del(up->channel_oil, __PRETTY_FUNCTION__);
	upstream_channel_oil_detach(up);

	list_delete(up->ifchannels);
	up->ifchannels = NULL;

	/*
	  notice that listnode_delete() can't be moved
	  into pim_upstream_free() because the later is
	  called by list_delete_all_node()
	*/
	if (up->parent && up->parent->sources)
		listnode_delete(up->parent->sources, up);
	up->parent = NULL;

	listnode_delete(pim->upstream_list, up);
	hash_release(pim->upstream_hash, up);

	if (notify_msdp) {
		pim_msdp_up_del(pim, &up->sg);
	}

	/* Deregister addr with Zebra NHT */
	nht_p.family = AF_INET;
	nht_p.prefixlen = IPV4_MAX_BITLEN;
	nht_p.u.prefix4 = up->upstream_addr;
	if (PIM_DEBUG_TRACE) {
		char buf[PREFIX2STR_BUFFER];
		prefix2str(&nht_p, buf, sizeof(buf));
		zlog_debug("%s: Deregister upstream %s addr %s with Zebra NHT",
			   __PRETTY_FUNCTION__, up->sg_str, buf);
	}
	pim_delete_tracked_nexthop(pim, &nht_p, up, NULL);

	pim_upstream_free(up);

	return NULL;
}

void pim_upstream_send_join(struct pim_upstream *up)
{
	if (PIM_DEBUG_TRACE) {
		char rpf_str[PREFIX_STRLEN];
		pim_addr_dump("<rpf?>", &up->rpf.rpf_addr, rpf_str,
			      sizeof(rpf_str));
		zlog_debug("%s: RPF'%s=%s(%s) for Interface %s",
			   __PRETTY_FUNCTION__, up->sg_str, rpf_str,
			   pim_upstream_state2str(up->join_state),
			   up->rpf.source_nexthop.interface->name);
		if (pim_rpf_addr_is_inaddr_any(&up->rpf)) {
			zlog_debug("%s: can't send join upstream: RPF'%s=%s",
				   __PRETTY_FUNCTION__, up->sg_str, rpf_str);
			/* warning only */
		}
	}

	/* send Join(S,G) to the current upstream neighbor */
	pim_jp_agg_single_upstream_send(&up->rpf, up, 1 /* join */);
}

static int on_join_timer(struct thread *t)
{
	struct pim_upstream *up;

	up = THREAD_ARG(t);

	/*
	 * In the case of a HFR we will not ahve anyone to send this to.
	 */
	if (PIM_UPSTREAM_FLAG_TEST_FHR(up->flags))
		return 0;

	/*
	 * Don't send the join if the outgoing interface is a loopback
	 * But since this might change leave the join timer running
	 */
	if (up->rpf.source_nexthop
		    .interface && !if_is_loopback(up->rpf.source_nexthop.interface))
		pim_upstream_send_join(up);

	join_timer_start(up);

	return 0;
}

static void join_timer_stop(struct pim_upstream *up)
{
	struct pim_neighbor *nbr;

	THREAD_OFF(up->t_join_timer);

	nbr = pim_neighbor_find(up->rpf.source_nexthop.interface,
				up->rpf.rpf_addr.u.prefix4);

	if (nbr)
		pim_jp_agg_remove_group(nbr->upstream_jp_agg, up);

	pim_jp_agg_upstream_verification(up, false);
}

void join_timer_start(struct pim_upstream *up)
{
	struct pim_neighbor *nbr = NULL;

	if (up->rpf.source_nexthop.interface) {
		nbr = pim_neighbor_find(up->rpf.source_nexthop.interface,
					up->rpf.rpf_addr.u.prefix4);

		if (PIM_DEBUG_PIM_EVENTS) {
			zlog_debug(
				"%s: starting %d sec timer for upstream (S,G)=%s",
				__PRETTY_FUNCTION__, qpim_t_periodic,
				up->sg_str);
		}
	}

	if (nbr)
		pim_jp_agg_add_group(nbr->upstream_jp_agg, up, 1);
	else {
		THREAD_OFF(up->t_join_timer);
		thread_add_timer(master, on_join_timer, up, qpim_t_periodic,
				 &up->t_join_timer);
	}
	pim_jp_agg_upstream_verification(up, true);
}

/*
 * This is only called when we are switching the upstream
 * J/P from one neighbor to another
 *
 * As such we need to remove from the old list and
 * add to the new list.
 */
void pim_upstream_join_timer_restart(struct pim_upstream *up,
				     struct pim_rpf *old)
{
	// THREAD_OFF(up->t_join_timer);
	join_timer_start(up);
}

static void pim_upstream_join_timer_restart_msec(struct pim_upstream *up,
						 int interval_msec)
{
	if (PIM_DEBUG_PIM_EVENTS) {
		zlog_debug("%s: restarting %d msec timer for upstream (S,G)=%s",
			   __PRETTY_FUNCTION__, interval_msec, up->sg_str);
	}

	THREAD_OFF(up->t_join_timer);
	thread_add_timer_msec(master, on_join_timer, up, interval_msec,
			      &up->t_join_timer);
}

void pim_upstream_join_suppress(struct pim_upstream *up,
				struct in_addr rpf_addr, int holdtime)
{
	long t_joinsuppress_msec;
	long join_timer_remain_msec;

	t_joinsuppress_msec =
		MIN(pim_if_t_suppressed_msec(up->rpf.source_nexthop.interface),
		    1000 * holdtime);

	join_timer_remain_msec = pim_time_timer_remain_msec(up->t_join_timer);

	if (PIM_DEBUG_TRACE) {
		char rpf_str[INET_ADDRSTRLEN];
		pim_inet4_dump("<rpf?>", rpf_addr, rpf_str, sizeof(rpf_str));
		zlog_debug(
			"%s %s: detected Join%s to RPF'(S,G)=%s: join_timer=%ld msec t_joinsuppress=%ld msec",
			__FILE__, __PRETTY_FUNCTION__, up->sg_str, rpf_str,
			join_timer_remain_msec, t_joinsuppress_msec);
	}

	if (join_timer_remain_msec < t_joinsuppress_msec) {
		if (PIM_DEBUG_TRACE) {
			zlog_debug(
				"%s %s: suppressing Join(S,G)=%s for %ld msec",
				__FILE__, __PRETTY_FUNCTION__, up->sg_str,
				t_joinsuppress_msec);
		}

		pim_upstream_join_timer_restart_msec(up, t_joinsuppress_msec);
	}
}

void pim_upstream_join_timer_decrease_to_t_override(const char *debug_label,
						    struct pim_upstream *up)
{
	long join_timer_remain_msec;
	int t_override_msec;

	join_timer_remain_msec = pim_time_timer_remain_msec(up->t_join_timer);
	t_override_msec =
		pim_if_t_override_msec(up->rpf.source_nexthop.interface);

	if (PIM_DEBUG_TRACE) {
		char rpf_str[INET_ADDRSTRLEN];
		pim_inet4_dump("<rpf?>", up->rpf.rpf_addr.u.prefix4, rpf_str,
			       sizeof(rpf_str));
		zlog_debug(
			"%s: to RPF'%s=%s: join_timer=%ld msec t_override=%d msec",
			debug_label, up->sg_str, rpf_str,
			join_timer_remain_msec, t_override_msec);
	}

	if (join_timer_remain_msec > t_override_msec) {
		if (PIM_DEBUG_TRACE) {
			zlog_debug(
				"%s: decreasing (S,G)=%s join timer to t_override=%d msec",
				debug_label, up->sg_str, t_override_msec);
		}

		pim_upstream_join_timer_restart_msec(up, t_override_msec);
	}
}

static void forward_on(struct pim_upstream *up)
{
	struct listnode *chnode;
	struct listnode *chnextnode;
	struct pim_ifchannel *ch = NULL;

	/* scan (S,G) state */
	for (ALL_LIST_ELEMENTS(up->ifchannels, chnode, chnextnode, ch)) {
		if (pim_macro_chisin_oiflist(ch))
			pim_forward_start(ch);

	} /* scan iface channel list */
}

static void forward_off(struct pim_upstream *up)
{
	struct listnode *chnode;
	struct listnode *chnextnode;
	struct pim_ifchannel *ch;

	/* scan per-interface (S,G) state */
	for (ALL_LIST_ELEMENTS(up->ifchannels, chnode, chnextnode, ch)) {

		pim_forward_stop(ch);

	} /* scan iface channel list */
}

static int pim_upstream_could_register(struct pim_upstream *up)
{
	struct pim_interface *pim_ifp = NULL;

	if (up->rpf.source_nexthop.interface)
		pim_ifp = up->rpf.source_nexthop.interface->info;
	else {
		if (PIM_DEBUG_TRACE)
			zlog_debug("%s: up %s RPF is not present",
				   __PRETTY_FUNCTION__, up->sg_str);
	}

	if (pim_ifp && PIM_I_am_DR(pim_ifp)
	    && pim_if_connected_to_source(up->rpf.source_nexthop.interface,
					  up->sg.src))
		return 1;

	return 0;
}

/* Source registration is supressed for SSM groups. When the SSM range changes
 * we re-revaluate register setup for existing upstream entries */
void pim_upstream_register_reevaluate(struct pim_instance *pim)
{
	struct listnode *upnode;
	struct pim_upstream *up;

	for (ALL_LIST_ELEMENTS_RO(pim->upstream_list, upnode, up)) {
		/* If FHR is set CouldRegister is True. Also check if the flow
		 * is actually active; if it is not kat setup will trigger
		 * source
		 * registration whenever the flow becomes active. */
		if (!PIM_UPSTREAM_FLAG_TEST_FHR(up->flags) || !up->t_ka_timer)
			continue;

		if (pim_is_grp_ssm(pim, up->sg.grp)) {
			/* clear the register state  for SSM groups */
			if (up->reg_state != PIM_REG_NOINFO) {
				if (PIM_DEBUG_PIM_EVENTS)
					zlog_debug(
						"Clear register for %s as G is now SSM",
						up->sg_str);
				/* remove regiface from the OIL if it is there*/
				pim_channel_del_oif(up->channel_oil,
						    pim->regiface,
						    PIM_OIF_FLAG_PROTO_PIM);
				up->reg_state = PIM_REG_NOINFO;
			}
		} else {
			/* register ASM sources with the RP */
			if (up->reg_state == PIM_REG_NOINFO) {
				if (PIM_DEBUG_PIM_EVENTS)
					zlog_debug(
						"Register %s as G is now ASM",
						up->sg_str);
				pim_channel_add_oif(up->channel_oil,
						    pim->regiface,
						    PIM_OIF_FLAG_PROTO_PIM);
				up->reg_state = PIM_REG_JOIN;
			}
		}
	}
}

void pim_upstream_switch(struct pim_upstream *up,
			 enum pim_upstream_state new_state)
{
	enum pim_upstream_state old_state = up->join_state;

	if (PIM_DEBUG_PIM_EVENTS) {
		zlog_debug("%s: PIM_UPSTREAM_%s: (S,G) old: %s new: %s",
			   __PRETTY_FUNCTION__, up->sg_str,
			   pim_upstream_state2str(up->join_state),
			   pim_upstream_state2str(new_state));
	}

	up->join_state = new_state;
	if (old_state != new_state)
		up->state_transition = pim_time_monotonic_sec();

	pim_upstream_update_assert_tracking_desired(up);

	if (new_state == PIM_UPSTREAM_JOINED) {
		if (old_state != PIM_UPSTREAM_JOINED) {
			int old_fhr = PIM_UPSTREAM_FLAG_TEST_FHR(up->flags);
			forward_on(up);
			pim_msdp_up_join_state_changed(up);
			if (pim_upstream_could_register(up)) {
				PIM_UPSTREAM_FLAG_SET_FHR(up->flags);
				if (!old_fhr
				    && PIM_UPSTREAM_FLAG_TEST_SRC_STREAM(
					       up->flags)) {
					pim_upstream_keep_alive_timer_start(
						up, qpim_keep_alive_time);
					pim_register_join(up);
				}
			} else {
				pim_upstream_send_join(up);
				join_timer_start(up);
			}
		} else {
			forward_on(up);
		}
	} else {

		forward_off(up);
		if (old_state == PIM_UPSTREAM_JOINED)
			pim_msdp_up_join_state_changed(up);

		/* IHR, Trigger SGRpt on *,G IIF to prune S,G from RPT towards
		   RP.
		   If I am RP for G then send S,G prune to its IIF. */
		if (pim_upstream_is_sg_rpt(up) && up->parent
		    && !I_am_RP(up->channel_oil->pim, up->sg.grp)) {
			if (PIM_DEBUG_PIM_TRACE_DETAIL)
				zlog_debug(
					"%s: *,G IIF %s S,G IIF %s ",
					__PRETTY_FUNCTION__,
					up->parent->rpf.source_nexthop
						.interface->name,
					up->rpf.source_nexthop.interface->name);
			pim_jp_agg_single_upstream_send(&up->parent->rpf,
							up->parent,
							1 /* (W,G) Join */);
		} else
			pim_jp_agg_single_upstream_send(&up->rpf, up,
							0 /* prune */);
		join_timer_stop(up);
	}
}

int pim_upstream_compare(void *arg1, void *arg2)
{
	const struct pim_upstream *up1 = (const struct pim_upstream *)arg1;
	const struct pim_upstream *up2 = (const struct pim_upstream *)arg2;

	if (ntohl(up1->sg.grp.s_addr) < ntohl(up2->sg.grp.s_addr))
		return -1;

	if (ntohl(up1->sg.grp.s_addr) > ntohl(up2->sg.grp.s_addr))
		return 1;

	if (ntohl(up1->sg.src.s_addr) < ntohl(up2->sg.src.s_addr))
		return -1;

	if (ntohl(up1->sg.src.s_addr) > ntohl(up2->sg.src.s_addr))
		return 1;

	return 0;
}

static struct pim_upstream *pim_upstream_new(struct pim_instance *pim,
					     struct prefix_sg *sg,
					     struct interface *incoming,
					     int flags)
{
	enum pim_rpf_result rpf_result;
	struct pim_interface *pim_ifp;
	struct pim_upstream *up;

	up = XCALLOC(MTYPE_PIM_UPSTREAM, sizeof(*up));
	if (!up) {
		zlog_err("%s: PIM XCALLOC(%zu) failure", __PRETTY_FUNCTION__,
			 sizeof(*up));
		return NULL;
	}

	up->sg = *sg;
	pim_str_sg_set(sg, up->sg_str);
	up = hash_get(pim->upstream_hash, up, hash_alloc_intern);
	if (!pim_rp_set_upstream_addr(pim, &up->upstream_addr, sg->src,
				      sg->grp)) {
		if (PIM_DEBUG_TRACE)
			zlog_debug("%s: Received a (*,G) with no RP configured",
				   __PRETTY_FUNCTION__);

		hash_release(pim->upstream_hash, up);
		XFREE(MTYPE_PIM_UPSTREAM, up);
		return NULL;
	}

	up->parent = pim_upstream_find_parent(pim, up);
	if (up->sg.src.s_addr == INADDR_ANY) {
		up->sources = list_new();
		up->sources->cmp = pim_upstream_compare;
	} else
		up->sources = NULL;

	pim_upstream_find_new_children(pim, up);
	up->flags = flags;
	up->ref_count = 1;
	up->t_join_timer = NULL;
	up->t_ka_timer = NULL;
	up->t_rs_timer = NULL;
	up->t_msdp_reg_timer = NULL;
	up->join_state = PIM_UPSTREAM_NOTJOINED;
	up->reg_state = PIM_REG_NOINFO;
	up->state_transition = pim_time_monotonic_sec();
	up->channel_oil = NULL;
	up->sptbit = PIM_UPSTREAM_SPTBIT_FALSE;

	up->rpf.source_nexthop.interface = NULL;
	up->rpf.source_nexthop.mrib_nexthop_addr.family = AF_INET;
	up->rpf.source_nexthop.mrib_nexthop_addr.u.prefix4.s_addr =
		PIM_NET_INADDR_ANY;
	up->rpf.source_nexthop.mrib_metric_preference =
		qpim_infinite_assert_metric.metric_preference;
	up->rpf.source_nexthop.mrib_route_metric =
		qpim_infinite_assert_metric.route_metric;
	up->rpf.rpf_addr.family = AF_INET;
	up->rpf.rpf_addr.u.prefix4.s_addr = PIM_NET_INADDR_ANY;

	up->ifchannels = list_new();
	up->ifchannels->cmp = (int (*)(void *, void *))pim_ifchannel_compare;

	if (up->sg.src.s_addr != INADDR_ANY)
		wheel_add_item(pim->upstream_sg_wheel, up);

	rpf_result = pim_rpf_update(pim, up, NULL, 1);
	if (rpf_result == PIM_RPF_FAILURE) {
		struct prefix nht_p;

		if (PIM_DEBUG_TRACE)
			zlog_debug(
				"%s: Attempting to create upstream(%s), Unable to RPF for source",
				__PRETTY_FUNCTION__, up->sg_str);

		nht_p.family = AF_INET;
		nht_p.prefixlen = IPV4_MAX_BITLEN;
		nht_p.u.prefix4 = up->upstream_addr;
		pim_delete_tracked_nexthop(pim, &nht_p, up, NULL);

		if (up->parent) {
			listnode_delete(up->parent->sources, up);
			up->parent = NULL;
		}

		if (up->sg.src.s_addr != INADDR_ANY)
			wheel_remove_item(pim->upstream_sg_wheel, up);

		pim_upstream_remove_children(pim, up);
		if (up->sources)
			list_delete(up->sources);

		hash_release(pim->upstream_hash, up);
		XFREE(MTYPE_PIM_UPSTREAM, up);
		return NULL;
	}

	if (up->rpf.source_nexthop.interface) {
		pim_ifp = up->rpf.source_nexthop.interface->info;
		if (pim_ifp)
			up->channel_oil = pim_channel_oil_add(
				pim, &up->sg, pim_ifp->mroute_vif_index);
	}
	listnode_add_sort(pim->upstream_list, up);

	if (PIM_DEBUG_TRACE) {
		zlog_debug(
			"%s: Created Upstream %s upstream_addr %s ref count %d increment",
			__PRETTY_FUNCTION__, up->sg_str,
			inet_ntoa(up->upstream_addr), up->ref_count);
	}

	return up;
}

struct pim_upstream *pim_upstream_find(struct pim_instance *pim,
				       struct prefix_sg *sg)
{
	struct pim_upstream lookup;
	struct pim_upstream *up = NULL;

	lookup.sg = *sg;
	up = hash_lookup(pim->upstream_hash, &lookup);
	return up;
}

struct pim_upstream *pim_upstream_find_or_add(struct prefix_sg *sg,
					      struct interface *incoming,
					      int flags, const char *name)
{
	struct pim_upstream *up;
	struct pim_interface *pim_ifp;

	pim_ifp = incoming->info;

	up = pim_upstream_find(pim_ifp->pim, sg);

	if (up) {
		if (!(up->flags & flags)) {
			up->flags |= flags;
			up->ref_count++;
			if (PIM_DEBUG_TRACE)
				zlog_debug(
					"%s(%s): upstream %s ref count %d increment",
					__PRETTY_FUNCTION__, name, up->sg_str,
					up->ref_count);
		}
	} else
		up = pim_upstream_add(pim_ifp->pim, sg, incoming, flags, name);

	return up;
}

void pim_upstream_ref(struct pim_upstream *up, int flags, const char *name)
{
	up->flags |= flags;
	++up->ref_count;
	if (PIM_DEBUG_TRACE)
		zlog_debug("%s(%s): upstream %s ref count %d increment",
			   __PRETTY_FUNCTION__, name, up->sg_str,
			   up->ref_count);
}

struct pim_upstream *pim_upstream_add(struct pim_instance *pim,
				      struct prefix_sg *sg,
				      struct interface *incoming, int flags,
				      const char *name)
{
	struct pim_upstream *up = NULL;
	int found = 0;

	up = pim_upstream_find(pim, sg);
	if (up) {
		pim_upstream_ref(up, flags, name);
		found = 1;
	} else {
		up = pim_upstream_new(pim, sg, incoming, flags);
	}

	if (PIM_DEBUG_TRACE) {
		if (up) {
			char buf[PREFIX2STR_BUFFER];
			prefix2str(&up->rpf.rpf_addr, buf, sizeof(buf));
			zlog_debug("%s(%s): %s, iif %s (%s) found: %d: ref_count: %d",
		   __PRETTY_FUNCTION__, name,
		   up->sg_str, buf, up->rpf.source_nexthop.interface ?
                   up->rpf.source_nexthop.interface->name : "NIL" ,
		   found, up->ref_count);
		} else
			zlog_debug("%s(%s): (%s) failure to create",
				   __PRETTY_FUNCTION__, name,
				   pim_str_sg_dump(sg));
	}

	return up;
}

/*
 * Passed in up must be the upstream for ch.  starch is NULL if no
 * information
 */
int pim_upstream_evaluate_join_desired_interface(struct pim_upstream *up,
						 struct pim_ifchannel *ch,
						 struct pim_ifchannel *starch)
{
	if (ch) {
		if (PIM_IF_FLAG_TEST_S_G_RPT(ch->flags))
			return 0;

		if (!pim_macro_ch_lost_assert(ch)
		    && pim_macro_chisin_joins_or_include(ch))
			return 1;
	}

	/*
	 * joins (*,G)
	 */
	if (starch) {
		if (PIM_IF_FLAG_TEST_S_G_RPT(starch->upstream->flags))
			return 0;

		if (!pim_macro_ch_lost_assert(starch)
		    && pim_macro_chisin_joins_or_include(starch))
			return 1;
	}

	return 0;
}

/*
  Evaluate JoinDesired(S,G):

  JoinDesired(S,G) is true if there is a downstream (S,G) interface I
  in the set:

  inherited_olist(S,G) =
  joins(S,G) (+) pim_include(S,G) (-) lost_assert(S,G)

  JoinDesired(S,G) may be affected by changes in the following:

  pim_ifp->primary_address
  pim_ifp->pim_dr_addr
  ch->ifassert_winner_metric
  ch->ifassert_winner
  ch->local_ifmembership
  ch->ifjoin_state
  ch->upstream->rpf.source_nexthop.mrib_metric_preference
  ch->upstream->rpf.source_nexthop.mrib_route_metric
  ch->upstream->rpf.source_nexthop.interface

  See also pim_upstream_update_join_desired() below.
 */
int pim_upstream_evaluate_join_desired(struct pim_instance *pim,
				       struct pim_upstream *up)
{
	struct interface *ifp;
	struct listnode *node;
	struct pim_ifchannel *ch, *starch;
	struct pim_upstream *starup = up->parent;
	int ret = 0;

	for (ALL_LIST_ELEMENTS_RO(vrf_iflist(pim->vrf_id), node, ifp)) {
		if (!ifp->info)
			continue;

		ch = pim_ifchannel_find(ifp, &up->sg);

		if (starup)
			starch = pim_ifchannel_find(ifp, &starup->sg);
		else
			starch = NULL;

		if (!ch && !starch)
			continue;

		ret += pim_upstream_evaluate_join_desired_interface(up, ch,
								    starch);
	} /* scan iface channel list */

	return ret; /* false */
}

/*
  See also pim_upstream_evaluate_join_desired() above.
*/
void pim_upstream_update_join_desired(struct pim_instance *pim,
				      struct pim_upstream *up)
{
	int was_join_desired; /* boolean */
	int is_join_desired;  /* boolean */

	was_join_desired = PIM_UPSTREAM_FLAG_TEST_DR_JOIN_DESIRED(up->flags);

	is_join_desired = pim_upstream_evaluate_join_desired(pim, up);
	if (is_join_desired)
		PIM_UPSTREAM_FLAG_SET_DR_JOIN_DESIRED(up->flags);
	else
		PIM_UPSTREAM_FLAG_UNSET_DR_JOIN_DESIRED(up->flags);

	/* switched from false to true */
	if (is_join_desired && !was_join_desired) {
		pim_upstream_switch(up, PIM_UPSTREAM_JOINED);
		return;
	}

	/* switched from true to false */
	if (!is_join_desired && was_join_desired) {
		pim_upstream_switch(up, PIM_UPSTREAM_NOTJOINED);
		return;
	}
}

/*
  RFC 4601 4.5.7. Sending (S,G) Join/Prune Messages
  Transitions from Joined State
  RPF'(S,G) GenID changes

  The upstream (S,G) state machine remains in Joined state.  If the
  Join Timer is set to expire in more than t_override seconds, reset
  it so that it expires after t_override seconds.
*/
void pim_upstream_rpf_genid_changed(struct pim_instance *pim,
				    struct in_addr neigh_addr)
{
	struct listnode *up_node;
	struct listnode *up_nextnode;
	struct pim_upstream *up;

	/*
	 * Scan all (S,G) upstreams searching for RPF'(S,G)=neigh_addr
	 */
	for (ALL_LIST_ELEMENTS(pim->upstream_list, up_node, up_nextnode, up)) {

		if (PIM_DEBUG_TRACE) {
			char neigh_str[INET_ADDRSTRLEN];
			char rpf_addr_str[PREFIX_STRLEN];
			pim_inet4_dump("<neigh?>", neigh_addr, neigh_str,
				       sizeof(neigh_str));
			pim_addr_dump("<rpf?>", &up->rpf.rpf_addr, rpf_addr_str,
				      sizeof(rpf_addr_str));
			zlog_debug(
				"%s: matching neigh=%s against upstream (S,G)=%s joined=%d rpf_addr=%s",
				__PRETTY_FUNCTION__, neigh_str, up->sg_str,
				up->join_state == PIM_UPSTREAM_JOINED,
				rpf_addr_str);
		}

		/* consider only (S,G) upstream in Joined state */
		if (up->join_state != PIM_UPSTREAM_JOINED)
			continue;

		/* match RPF'(S,G)=neigh_addr */
		if (up->rpf.rpf_addr.u.prefix4.s_addr != neigh_addr.s_addr)
			continue;

		pim_upstream_join_timer_decrease_to_t_override(
			"RPF'(S,G) GenID change", up);
	}
}


void pim_upstream_rpf_interface_changed(struct pim_upstream *up,
					struct interface *old_rpf_ifp)
{
	struct listnode *chnode;
	struct listnode *chnextnode;
	struct pim_ifchannel *ch;

	/* search all ifchannels */
	for (ALL_LIST_ELEMENTS(up->ifchannels, chnode, chnextnode, ch)) {
		if (ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
			if (
				/* RPF_interface(S) was NOT I */
				(old_rpf_ifp == ch->interface) &&
				/* RPF_interface(S) stopped being I */
				(ch->upstream->rpf.source_nexthop
					 .interface != ch->interface)) {
				assert_action_a5(ch);
			}
		} /* PIM_IFASSERT_I_AM_LOSER */

		pim_ifchannel_update_assert_tracking_desired(ch);
	}
}

void pim_upstream_update_could_assert(struct pim_upstream *up)
{
	struct listnode *chnode;
	struct listnode *chnextnode;
	struct pim_ifchannel *ch;

	/* scan per-interface (S,G) state */
	for (ALL_LIST_ELEMENTS(up->ifchannels, chnode, chnextnode, ch)) {
		pim_ifchannel_update_could_assert(ch);
	} /* scan iface channel list */
}

void pim_upstream_update_my_assert_metric(struct pim_upstream *up)
{
	struct listnode *chnode;
	struct listnode *chnextnode;
	struct pim_ifchannel *ch;

	/* scan per-interface (S,G) state */
	for (ALL_LIST_ELEMENTS(up->ifchannels, chnode, chnextnode, ch)) {
		pim_ifchannel_update_my_assert_metric(ch);

	} /* scan iface channel list */
}

static void pim_upstream_update_assert_tracking_desired(struct pim_upstream *up)
{
	struct listnode *chnode;
	struct listnode *chnextnode;
	struct pim_interface *pim_ifp;
	struct pim_ifchannel *ch;

	/* scan per-interface (S,G) state */
	for (ALL_LIST_ELEMENTS(up->ifchannels, chnode, chnextnode, ch)) {
		if (!ch->interface)
			continue;
		pim_ifp = ch->interface->info;
		if (!pim_ifp)
			continue;

		pim_ifchannel_update_assert_tracking_desired(ch);

	} /* scan iface channel list */
}

/* When kat is stopped CouldRegister goes to false so we need to
 * transition  the (S, G) on FHR to NI state and remove reg tunnel
 * from the OIL */
static void pim_upstream_fhr_kat_expiry(struct pim_instance *pim,
					struct pim_upstream *up)
{
	if (!PIM_UPSTREAM_FLAG_TEST_FHR(up->flags))
		return;

	if (PIM_DEBUG_TRACE)
		zlog_debug("kat expired on %s; clear fhr reg state",
			   up->sg_str);

	/* stop reg-stop timer */
	THREAD_OFF(up->t_rs_timer);
	/* remove regiface from the OIL if it is there*/
	pim_channel_del_oif(up->channel_oil, pim->regiface,
			    PIM_OIF_FLAG_PROTO_PIM);
	/* clear the register state */
	up->reg_state = PIM_REG_NOINFO;
	PIM_UPSTREAM_FLAG_UNSET_FHR(up->flags);
}

/* When kat is started CouldRegister can go to true. And if it does we
 * need to transition  the (S, G) on FHR to JOINED state and add reg tunnel
 * to the OIL */
static void pim_upstream_fhr_kat_start(struct pim_upstream *up)
{
	if (pim_upstream_could_register(up)) {
		if (PIM_DEBUG_TRACE)
			zlog_debug(
				"kat started on %s; set fhr reg state to joined",
				up->sg_str);

		PIM_UPSTREAM_FLAG_SET_FHR(up->flags);
		if (up->reg_state == PIM_REG_NOINFO)
			pim_register_join(up);
	}
}

/*
 * On an RP, the PMBR value must be cleared when the
 * Keepalive Timer expires
 * KAT expiry indicates that flow is inactive. If the flow was created or
 * maintained by activity now is the time to deref it.
 */
static int pim_upstream_keep_alive_timer(struct thread *t)
{
	struct pim_upstream *up;
	struct pim_instance *pim;

	up = THREAD_ARG(t);
	pim = up->channel_oil->pim;

	if (I_am_RP(pim, up->sg.grp)) {
		pim_br_clear_pmbr(&up->sg);
		/*
		 * We need to do more here :)
		 * But this is the start.
		 */
	}

	/* source is no longer active - pull the SA from MSDP's cache */
	pim_msdp_sa_local_del(pim, &up->sg);

	/* if entry was created because of activity we need to deref it */
	if (PIM_UPSTREAM_FLAG_TEST_SRC_STREAM(up->flags)) {
		pim_upstream_fhr_kat_expiry(pim, up);
		if (PIM_DEBUG_TRACE)
			zlog_debug("kat expired on %s; remove stream reference",
				   up->sg_str);
		PIM_UPSTREAM_FLAG_UNSET_SRC_STREAM(up->flags);
		pim_upstream_del(pim, up, __PRETTY_FUNCTION__);
	} else if (PIM_UPSTREAM_FLAG_TEST_SRC_LHR(up->flags)) {
		PIM_UPSTREAM_FLAG_UNSET_SRC_LHR(up->flags);
		pim_upstream_del(pim, up, __PRETTY_FUNCTION__);
	}

	return 0;
}

void pim_upstream_keep_alive_timer_start(struct pim_upstream *up, uint32_t time)
{
	if (!PIM_UPSTREAM_FLAG_TEST_SRC_STREAM(up->flags)) {
		if (PIM_DEBUG_TRACE)
			zlog_debug("kat start on %s with no stream reference",
				   up->sg_str);
	}
	THREAD_OFF(up->t_ka_timer);
	thread_add_timer(master, pim_upstream_keep_alive_timer, up, time,
			 &up->t_ka_timer);

	/* any time keepalive is started against a SG we will have to
	 * re-evaluate our active source database */
	pim_msdp_sa_local_update(up);
}

/* MSDP on RP needs to know if a source is registerable to this RP */
static int pim_upstream_msdp_reg_timer(struct thread *t)
{
	struct pim_upstream *up = THREAD_ARG(t);
	struct pim_instance *pim = up->channel_oil->pim;

	/* source is no longer active - pull the SA from MSDP's cache */
	pim_msdp_sa_local_del(pim, &up->sg);
	return 1;
}
void pim_upstream_msdp_reg_timer_start(struct pim_upstream *up)
{
	THREAD_OFF(up->t_msdp_reg_timer);
	thread_add_timer(master, pim_upstream_msdp_reg_timer, up,
			 PIM_MSDP_REG_RXED_PERIOD, &up->t_msdp_reg_timer);

	pim_msdp_sa_local_update(up);
}

/*
 * 4.2.1 Last-Hop Switchover to the SPT
 *
 *  In Sparse-Mode PIM, last-hop routers join the shared tree towards the
 *  RP.  Once traffic from sources to joined groups arrives at a last-hop
 *  router, it has the option of switching to receive the traffic on a
 *  shortest path tree (SPT).
 *
 *  The decision for a router to switch to the SPT is controlled as
 *  follows:
 *
 *    void
 *    CheckSwitchToSpt(S,G) {
 *      if ( ( pim_include(*,G) (-) pim_exclude(S,G)
 *             (+) pim_include(S,G) != NULL )
 *           AND SwitchToSptDesired(S,G) ) {
 *             # Note: Restarting the KAT will result in the SPT switch
 *             set KeepaliveTimer(S,G) to Keepalive_Period
 *      }
 *    }
 *
 *  SwitchToSptDesired(S,G) is a policy function that is implementation
 *  defined.  An "infinite threshold" policy can be implemented by making
 *  SwitchToSptDesired(S,G) return false all the time.  A "switch on
 *  first packet" policy can be implemented by making
 *  SwitchToSptDesired(S,G) return true once a single packet has been
 *  received for the source and group.
 */
int pim_upstream_switch_to_spt_desired(struct pim_instance *pim,
				       struct prefix_sg *sg)
{
	if (I_am_RP(pim, sg->grp))
		return 1;

	return 0;
}

int pim_upstream_is_sg_rpt(struct pim_upstream *up)
{
	struct listnode *chnode;
	struct pim_ifchannel *ch;

	for (ALL_LIST_ELEMENTS_RO(up->ifchannels, chnode, ch)) {
		if (PIM_IF_FLAG_TEST_S_G_RPT(ch->flags))
			return 1;
	}

	return 0;
}
/*
 *  After receiving a packet set SPTbit:
 *   void
 *   Update_SPTbit(S,G,iif) {
 *     if ( iif == RPF_interface(S)
 *           AND JoinDesired(S,G) == TRUE
 *           AND ( DirectlyConnected(S) == TRUE
 *                 OR RPF_interface(S) != RPF_interface(RP(G))
 *                 OR inherited_olist(S,G,rpt) == NULL
 *                 OR ( ( RPF'(S,G) == RPF'(*,G) ) AND
 *                      ( RPF'(S,G) != NULL ) )
 *                 OR ( I_Am_Assert_Loser(S,G,iif) ) {
 *        Set SPTbit(S,G) to TRUE
 *     }
 *   }
 */
void pim_upstream_set_sptbit(struct pim_upstream *up,
			     struct interface *incoming)
{
	struct pim_upstream *starup = up->parent;

	// iif == RPF_interfvace(S)
	if (up->rpf.source_nexthop.interface != incoming) {
		if (PIM_DEBUG_TRACE)
			zlog_debug(
				"%s: Incoming Interface: %s is different than RPF_interface(S) %s",
				__PRETTY_FUNCTION__, incoming->name,
				up->rpf.source_nexthop.interface->name);
		return;
	}

	// AND JoinDesired(S,G) == TRUE
	// FIXME

	// DirectlyConnected(S) == TRUE
	if (pim_if_connected_to_source(up->rpf.source_nexthop.interface,
				       up->sg.src)) {
		if (PIM_DEBUG_TRACE)
			zlog_debug("%s: %s is directly connected to the source",
				   __PRETTY_FUNCTION__, up->sg_str);
		up->sptbit = PIM_UPSTREAM_SPTBIT_TRUE;
		return;
	}

	// OR RPF_interface(S) != RPF_interface(RP(G))
	if (!starup
	    || up->rpf.source_nexthop
			       .interface != starup->rpf.source_nexthop.interface) {
		if (PIM_DEBUG_TRACE)
			zlog_debug(
				"%s: %s RPF_interface(S) != RPF_interface(RP(G))",
				__PRETTY_FUNCTION__, up->sg_str);
		up->sptbit = PIM_UPSTREAM_SPTBIT_TRUE;
		return;
	}

	// OR inherited_olist(S,G,rpt) == NULL
	if (pim_upstream_is_sg_rpt(up)
	    && pim_upstream_empty_inherited_olist(up)) {
		if (PIM_DEBUG_TRACE)
			zlog_debug("%s: %s OR inherited_olist(S,G,rpt) == NULL",
				   __PRETTY_FUNCTION__, up->sg_str);
		up->sptbit = PIM_UPSTREAM_SPTBIT_TRUE;
		return;
	}

	// OR ( ( RPF'(S,G) == RPF'(*,G) ) AND
	//      ( RPF'(S,G) != NULL ) )
	if (up->parent && pim_rpf_is_same(&up->rpf, &up->parent->rpf)) {
		if (PIM_DEBUG_TRACE)
			zlog_debug("%s: %s RPF'(S,G) is the same as RPF'(*,G)",
				   __PRETTY_FUNCTION__, up->sg_str);
		up->sptbit = PIM_UPSTREAM_SPTBIT_TRUE;
		return;
	}

	return;
}

const char *pim_upstream_state2str(enum pim_upstream_state join_state)
{
	switch (join_state) {
	case PIM_UPSTREAM_NOTJOINED:
		return "NotJoined";
		break;
	case PIM_UPSTREAM_JOINED:
		return "Joined";
		break;
	}
	return "Unknown";
}

const char *pim_reg_state2str(enum pim_reg_state reg_state, char *state_str)
{
	switch (reg_state) {
	case PIM_REG_NOINFO:
		strcpy(state_str, "RegNoInfo");
		break;
	case PIM_REG_JOIN:
		strcpy(state_str, "RegJoined");
		break;
	case PIM_REG_JOIN_PENDING:
		strcpy(state_str, "RegJoinPend");
		break;
	case PIM_REG_PRUNE:
		strcpy(state_str, "RegPrune");
		break;
	default:
		strcpy(state_str, "RegUnknown");
	}
	return state_str;
}

static int pim_upstream_register_stop_timer(struct thread *t)
{
	struct pim_interface *pim_ifp;
	struct pim_instance *pim;
	struct pim_upstream *up;
	struct pim_rpf *rpg;
	struct ip ip_hdr;
	up = THREAD_ARG(t);
	pim = up->channel_oil->pim;

	if (PIM_DEBUG_TRACE) {
		char state_str[PIM_REG_STATE_STR_LEN];
		zlog_debug("%s: (S,G)=%s upstream register stop timer %s",
			   __PRETTY_FUNCTION__, up->sg_str,
			   pim_reg_state2str(up->reg_state, state_str));
	}

	switch (up->reg_state) {
	case PIM_REG_JOIN_PENDING:
		up->reg_state = PIM_REG_JOIN;
		pim_channel_add_oif(up->channel_oil, pim->regiface,
				    PIM_OIF_FLAG_PROTO_PIM);
		break;
	case PIM_REG_JOIN:
		break;
	case PIM_REG_PRUNE:
		pim_ifp = up->rpf.source_nexthop.interface->info;
		if (!pim_ifp) {
			if (PIM_DEBUG_TRACE)
				zlog_debug(
					"%s: Interface: %s is not configured for pim",
					__PRETTY_FUNCTION__,
					up->rpf.source_nexthop.interface->name);
			return 0;
		}
		up->reg_state = PIM_REG_JOIN_PENDING;
		pim_upstream_start_register_stop_timer(up, 1);

		if (((up->channel_oil->cc.lastused / 100)
		     > PIM_KEEPALIVE_PERIOD)
		    && (I_am_RP(pim_ifp->pim, up->sg.grp))) {
			if (PIM_DEBUG_TRACE)
				zlog_debug(
					"%s: Stop sending the register, because I am the RP and we haven't seen a packet in a while",
					__PRETTY_FUNCTION__);
			return 0;
		}
		rpg = RP(pim_ifp->pim, up->sg.grp);
		memset(&ip_hdr, 0, sizeof(struct ip));
		ip_hdr.ip_p = PIM_IP_PROTO_PIM;
		ip_hdr.ip_hl = 5;
		ip_hdr.ip_v = 4;
		ip_hdr.ip_src = up->sg.src;
		ip_hdr.ip_dst = up->sg.grp;
		ip_hdr.ip_len = htons(20);
		// checksum is broken
		pim_register_send((uint8_t *)&ip_hdr, sizeof(struct ip),
				  pim_ifp->primary_address, rpg, 1, up);
		break;
	default:
		break;
	}

	return 0;
}

void pim_upstream_start_register_stop_timer(struct pim_upstream *up,
					    int null_register)
{
	uint32_t time;

	THREAD_TIMER_OFF(up->t_rs_timer);

	if (!null_register) {
		uint32_t lower = (0.5 * PIM_REGISTER_SUPPRESSION_PERIOD);
		uint32_t upper = (1.5 * PIM_REGISTER_SUPPRESSION_PERIOD);
		time = lower + (random() % (upper - lower + 1))
		       - PIM_REGISTER_PROBE_PERIOD;
	} else
		time = PIM_REGISTER_PROBE_PERIOD;

	if (PIM_DEBUG_TRACE) {
		zlog_debug(
			"%s: (S,G)=%s Starting upstream register stop timer %d",
			__PRETTY_FUNCTION__, up->sg_str, time);
	}
	thread_add_timer(master, pim_upstream_register_stop_timer, up, time,
			 &up->t_rs_timer);
}

int pim_upstream_inherited_olist_decide(struct pim_instance *pim,
					struct pim_upstream *up)
{
	struct interface *ifp;
	struct pim_interface *pim_ifp = NULL;
	struct pim_ifchannel *ch, *starch;
	struct listnode *node;
	struct pim_upstream *starup = up->parent;
	int output_intf = 0;

	if (up->rpf.source_nexthop.interface)
		pim_ifp = up->rpf.source_nexthop.interface->info;
	else {
		if (PIM_DEBUG_TRACE)
			zlog_debug("%s: up %s RPF is not present",
				   __PRETTY_FUNCTION__, up->sg_str);
	}
	if (pim_ifp && !up->channel_oil)
		up->channel_oil = pim_channel_oil_add(
			pim, &up->sg, pim_ifp->mroute_vif_index);

	for (ALL_LIST_ELEMENTS_RO(vrf_iflist(pim->vrf_id), node, ifp)) {
		if (!ifp->info)
			continue;

		ch = pim_ifchannel_find(ifp, &up->sg);

		if (starup)
			starch = pim_ifchannel_find(ifp, &starup->sg);
		else
			starch = NULL;

		if (!ch && !starch)
			continue;

		if (pim_upstream_evaluate_join_desired_interface(up, ch,
								 starch)) {
			int flag = PIM_OIF_FLAG_PROTO_PIM;

			if (!ch)
				flag = PIM_OIF_FLAG_PROTO_STAR;

			pim_channel_add_oif(up->channel_oil, ifp, flag);
			output_intf++;
		}
	}

	return output_intf;
}

/*
 * For a given upstream, determine the inherited_olist
 * and apply it.
 *
 * inherited_olist(S,G,rpt) =
 *           ( joins(*,*,RP(G)) (+) joins(*,G) (-) prunes(S,G,rpt) )
 *      (+) ( pim_include(*,G) (-) pim_exclude(S,G))
 *      (-) ( lost_assert(*,G) (+) lost_assert(S,G,rpt) )
 *
 *  inherited_olist(S,G) =
 *      inherited_olist(S,G,rpt) (+)
 *      joins(S,G) (+) pim_include(S,G) (-) lost_assert(S,G)
 *
 * return 1 if there are any output interfaces
 * return 0 if there are not any output interfaces
 */
int pim_upstream_inherited_olist(struct pim_instance *pim,
				 struct pim_upstream *up)
{
	int output_intf = pim_upstream_inherited_olist_decide(pim, up);

	/*
	 * If we have output_intf switch state to Join and work like normal
	 * If we don't have an output_intf that means we are probably a
	 * switch on a stick so turn on forwarding to just accept the
	 * incoming packets so we don't bother the other stuff!
	 */
	if (output_intf)
		pim_upstream_switch(up, PIM_UPSTREAM_JOINED);
	else
		forward_on(up);

	return output_intf;
}

int pim_upstream_empty_inherited_olist(struct pim_upstream *up)
{
	return pim_channel_oil_empty(up->channel_oil);
}

/*
 * When we have a new neighbor,
 * find upstreams that don't have their rpf_addr
 * set and see if the new neighbor allows
 * the join to be sent
 */
void pim_upstream_find_new_rpf(struct pim_instance *pim)
{
	struct listnode *up_node;
	struct listnode *up_nextnode;
	struct pim_upstream *up;

	/*
	 * Scan all (S,G) upstreams searching for RPF'(S,G)=neigh_addr
	 */
	for (ALL_LIST_ELEMENTS(pim->upstream_list, up_node, up_nextnode, up)) {
		if (pim_rpf_addr_is_inaddr_any(&up->rpf)) {
			if (PIM_DEBUG_TRACE)
				zlog_debug(
					"Upstream %s without a path to send join, checking",
					up->sg_str);
			pim_rpf_update(pim, up, NULL, 1);
		}
	}
}

static unsigned int pim_upstream_hash_key(void *arg)
{
	struct pim_upstream *up = (struct pim_upstream *)arg;

	return jhash_2words(up->sg.src.s_addr, up->sg.grp.s_addr, 0);
}

void pim_upstream_terminate(struct pim_instance *pim)
{
	if (pim->upstream_list)
		list_delete(pim->upstream_list);
	pim->upstream_list = NULL;

	if (pim->upstream_hash)
		hash_free(pim->upstream_hash);
	pim->upstream_hash = NULL;
}

static int pim_upstream_equal(const void *arg1, const void *arg2)
{
	const struct pim_upstream *up1 = (const struct pim_upstream *)arg1;
	const struct pim_upstream *up2 = (const struct pim_upstream *)arg2;

	if ((up1->sg.grp.s_addr == up2->sg.grp.s_addr)
	    && (up1->sg.src.s_addr == up2->sg.src.s_addr))
		return 1;

	return 0;
}

/* rfc4601:section-4.2:"Data Packet Forwarding Rules" defines
 * the cases where kat has to be restarted on rxing traffic -
 *
 * if( DirectlyConnected(S) == TRUE AND iif == RPF_interface(S) ) {
 * set KeepaliveTimer(S,G) to Keepalive_Period
 * # Note: a register state transition or UpstreamJPState(S,G)
 * # transition may happen as a result of restarting
 * # KeepaliveTimer, and must be dealt with here.
 * }
 * if( iif == RPF_interface(S) AND UpstreamJPState(S,G) == Joined AND
 * inherited_olist(S,G) != NULL ) {
 * set KeepaliveTimer(S,G) to Keepalive_Period
 * }
 */
static bool pim_upstream_kat_start_ok(struct pim_upstream *up)
{
	struct pim_instance *pim = up->channel_oil->pim;

	/* "iif == RPF_interface(S)" check has to be done by the kernel or hw
	 * so we will skip that here */
	if (pim_if_connected_to_source(up->rpf.source_nexthop.interface,
				       up->sg.src)) {
		return true;
	}

	if ((up->join_state == PIM_UPSTREAM_JOINED)
	    && !pim_upstream_empty_inherited_olist(up)) {
		/* XXX: I have added this RP check just for 3.2 and it's a
		 * digression from
		 * what rfc-4601 says. Till now we were only running KAT on FHR
		 * and RP and
		 * there is some angst around making the change to run it all
		 * routers that
		 * maintain the (S, G) state. This is tracked via CM-13601 and
		 * MUST be
		 * removed to handle spt turn-arounds correctly in a 3-tier clos
		 */
		if (I_am_RP(pim, up->sg.grp))
			return true;
	}

	return false;
}

/*
 * Code to check and see if we've received packets on a S,G mroute
 * and if so to set the SPT bit appropriately
 */
static void pim_upstream_sg_running(void *arg)
{
	struct pim_upstream *up = (struct pim_upstream *)arg;
	struct pim_instance *pim = up->channel_oil->pim;

	// No packet can have arrived here if this is the case
	if (!up->channel_oil->installed) {
		if (PIM_DEBUG_TRACE)
			zlog_debug("%s: %s is not installed in mroute",
				   __PRETTY_FUNCTION__, up->sg_str);
		return;
	}

	/*
	 * This is a bit of a hack
	 * We've noted that we should rescan but
	 * we've missed the window for doing so in
	 * pim_zebra.c for some reason.  I am
	 * only doing this at this point in time
	 * to get us up and working for the moment
	 */
	if (up->channel_oil->oil_inherited_rescan) {
		if (PIM_DEBUG_TRACE)
			zlog_debug(
				"%s: Handling unscanned inherited_olist for %s",
				__PRETTY_FUNCTION__, up->sg_str);
		pim_upstream_inherited_olist_decide(pim, up);
		up->channel_oil->oil_inherited_rescan = 0;
	}
	pim_mroute_update_counters(up->channel_oil);

	// Have we seen packets?
	if ((up->channel_oil->cc.oldpktcnt >= up->channel_oil->cc.pktcnt)
	    && (up->channel_oil->cc.lastused / 100 > 30)) {
		if (PIM_DEBUG_TRACE) {
			zlog_debug(
				"%s: %s old packet count is equal or lastused is greater than 30, (%ld,%ld,%lld)",
				__PRETTY_FUNCTION__, up->sg_str,
				up->channel_oil->cc.oldpktcnt,
				up->channel_oil->cc.pktcnt,
				up->channel_oil->cc.lastused / 100);
		}
		return;
	}

	if (pim_upstream_kat_start_ok(up)) {
		/* Add a source reference to the stream if
		 * one doesn't already exist */
		if (!PIM_UPSTREAM_FLAG_TEST_SRC_STREAM(up->flags)) {
			if (PIM_DEBUG_TRACE)
				zlog_debug(
					"source reference created on kat restart %s",
					up->sg_str);

			pim_upstream_ref(up, PIM_UPSTREAM_FLAG_MASK_SRC_STREAM,
					 __PRETTY_FUNCTION__);
			PIM_UPSTREAM_FLAG_SET_SRC_STREAM(up->flags);
			pim_upstream_fhr_kat_start(up);
		}
		pim_upstream_keep_alive_timer_start(up, qpim_keep_alive_time);
	} else if (PIM_UPSTREAM_FLAG_TEST_SRC_LHR(up->flags))
		pim_upstream_keep_alive_timer_start(up, qpim_keep_alive_time);

	if (up->sptbit != PIM_UPSTREAM_SPTBIT_TRUE) {
		pim_upstream_set_sptbit(up, up->rpf.source_nexthop.interface);
	}
	return;
}

void pim_upstream_add_lhr_star_pimreg(struct pim_instance *pim)
{
	struct pim_upstream *up;
	struct listnode *node;

	for (ALL_LIST_ELEMENTS_RO(pim->upstream_list, node, up)) {
		if (up->sg.src.s_addr != INADDR_ANY)
			continue;

		if (!PIM_UPSTREAM_FLAG_TEST_SRC_IGMP(up->flags))
			continue;

		pim_channel_add_oif(up->channel_oil, pim->regiface,
				    PIM_OIF_FLAG_PROTO_IGMP);
	}
}

void pim_upstream_spt_prefix_list_update(struct pim_instance *pim,
					 struct prefix_list *pl)
{
	const char *pname = prefix_list_name(pl);

	if (pim->spt.plist && strcmp(pim->spt.plist, pname) == 0) {
		pim_upstream_remove_lhr_star_pimreg(pim, pname);
	}
}

/*
 * nlist -> The new prefix list
 *
 * Per Group Application of pimreg to the OIL
 * If the prefix list tells us DENY then
 * we need to Switchover to SPT immediate
 * so add the pimreg.
 * If the prefix list tells us to ACCEPT than
 * we need to Never do the SPT so remove
 * the interface
 *
 */
void pim_upstream_remove_lhr_star_pimreg(struct pim_instance *pim,
					 const char *nlist)
{
	struct pim_upstream *up;
	struct listnode *node;
	struct prefix_list *np;
	struct prefix g;
	enum prefix_list_type apply_new;

	np = prefix_list_lookup(AFI_IP, nlist);

	g.family = AF_INET;
	g.prefixlen = IPV4_MAX_PREFIXLEN;

	for (ALL_LIST_ELEMENTS_RO(pim->upstream_list, node, up)) {
		if (up->sg.src.s_addr != INADDR_ANY)
			continue;

		if (!PIM_UPSTREAM_FLAG_TEST_SRC_IGMP(up->flags))
			continue;

		if (!nlist) {
			pim_channel_del_oif(up->channel_oil, pim->regiface,
					    PIM_OIF_FLAG_PROTO_IGMP);
			continue;
		}
		g.u.prefix4 = up->sg.grp;
		apply_new = prefix_list_apply(np, &g);
		if (apply_new == PREFIX_DENY)
			pim_channel_add_oif(up->channel_oil, pim->regiface,
					    PIM_OIF_FLAG_PROTO_IGMP);
		else
			pim_channel_del_oif(up->channel_oil, pim->regiface,
					    PIM_OIF_FLAG_PROTO_IGMP);
	}
}

void pim_upstream_init(struct pim_instance *pim)
{
	pim->upstream_sg_wheel =
		wheel_init(master, 31000, 100, pim_upstream_hash_key,
			   pim_upstream_sg_running);
	pim->upstream_hash = hash_create_size(8192, pim_upstream_hash_key,
					      pim_upstream_equal, NULL);

	pim->upstream_list = list_new();
	pim->upstream_list->del = (void (*)(void *))pim_upstream_free;
	pim->upstream_list->cmp = pim_upstream_compare;
}