Adding upstream version 8.4.4.upstream/8.4.4upstream

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

1 files changed, 1460 insertions, 0 deletions

diff --git a/pimd/pim_msdp.c b/pimd/pim_msdp.c
new file mode 100644
index 0000000..0711a63
--- /dev/null
+++ b/pimd/pim_msdp.c
@@ -0,0 +1,1460 @@
+/*
+ * IP MSDP for Quagga
+ * Copyright (C) 2016 Cumulus Networks, Inc.
+ *
+ * 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/jhash.h>
+#include <lib/log.h>
+#include <lib/prefix.h>
+#include <lib/sockunion.h>
+#include <lib/stream.h>
+#include <lib/thread.h>
+#include <lib/vty.h>
+#include <lib/plist.h>
+#include <lib/lib_errors.h>
+
+#include "pimd.h"
+#include "pim_memory.h"
+#include "pim_instance.h"
+#include "pim_iface.h"
+#include "pim_rp.h"
+#include "pim_str.h"
+#include "pim_time.h"
+#include "pim_upstream.h"
+#include "pim_oil.h"
+
+#include "pim_msdp.h"
+#include "pim_msdp_packet.h"
+#include "pim_msdp_socket.h"
+
+// struct pim_msdp pim_msdp, *msdp = &pim_msdp;
+
+static void pim_msdp_peer_listen(struct pim_msdp_peer *mp);
+static void pim_msdp_peer_cr_timer_setup(struct pim_msdp_peer *mp, bool start);
+static void pim_msdp_peer_ka_timer_setup(struct pim_msdp_peer *mp, bool start);
+static void pim_msdp_peer_hold_timer_setup(struct pim_msdp_peer *mp,
+					   bool start);
+static void pim_msdp_peer_free(struct pim_msdp_peer *mp);
+static void pim_msdp_enable(struct pim_instance *pim);
+static void pim_msdp_sa_adv_timer_setup(struct pim_instance *pim, bool start);
+static void pim_msdp_sa_deref(struct pim_msdp_sa *sa,
+			      enum pim_msdp_sa_flags flags);
+static int pim_msdp_mg_mbr_comp(const void *p1, const void *p2);
+static void pim_msdp_mg_mbr_free(struct pim_msdp_mg_mbr *mbr);
+
+/************************ SA cache management ******************************/
+static void pim_msdp_sa_timer_expiry_log(struct pim_msdp_sa *sa,
+					 const char *timer_str)
+{
+	zlog_debug("MSDP SA %s %s timer expired", sa->sg_str, timer_str);
+}
+
+/* RFC-3618:Sec-5.1 - global active source advertisement timer */
+static void pim_msdp_sa_adv_timer_cb(struct thread *t)
+{
+	struct pim_instance *pim = THREAD_ARG(t);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		zlog_debug("MSDP SA advertisement timer expired");
+	}
+
+	pim_msdp_sa_adv_timer_setup(pim, true /* start */);
+	pim_msdp_pkt_sa_tx(pim);
+}
+
+static void pim_msdp_sa_adv_timer_setup(struct pim_instance *pim, bool start)
+{
+	THREAD_OFF(pim->msdp.sa_adv_timer);
+	if (start) {
+		thread_add_timer(pim->msdp.master, pim_msdp_sa_adv_timer_cb,
+				 pim, PIM_MSDP_SA_ADVERTISMENT_TIME,
+				 &pim->msdp.sa_adv_timer);
+	}
+}
+
+/* RFC-3618:Sec-5.3 - SA cache state timer */
+static void pim_msdp_sa_state_timer_cb(struct thread *t)
+{
+	struct pim_msdp_sa *sa;
+
+	sa = THREAD_ARG(t);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		pim_msdp_sa_timer_expiry_log(sa, "state");
+	}
+
+	pim_msdp_sa_deref(sa, PIM_MSDP_SAF_PEER);
+}
+
+static void pim_msdp_sa_state_timer_setup(struct pim_msdp_sa *sa, bool start)
+{
+	THREAD_OFF(sa->sa_state_timer);
+	if (start) {
+		thread_add_timer(sa->pim->msdp.master,
+				 pim_msdp_sa_state_timer_cb, sa,
+				 PIM_MSDP_SA_HOLD_TIME, &sa->sa_state_timer);
+	}
+}
+
+static void pim_msdp_sa_upstream_del(struct pim_msdp_sa *sa)
+{
+	struct pim_upstream *up = sa->up;
+	if (!up) {
+		return;
+	}
+
+	sa->up = NULL;
+	if (PIM_UPSTREAM_FLAG_TEST_SRC_MSDP(up->flags)) {
+		PIM_UPSTREAM_FLAG_UNSET_SRC_MSDP(up->flags);
+		sa->flags |= PIM_MSDP_SAF_UP_DEL_IN_PROG;
+		up = pim_upstream_del(sa->pim, up, __func__);
+		/* re-eval joinDesired; clearing peer-msdp-sa flag can
+		 * cause JD to change
+		 */
+		if (up)
+			pim_upstream_update_join_desired(sa->pim, up);
+		sa->flags &= ~PIM_MSDP_SAF_UP_DEL_IN_PROG;
+	}
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		zlog_debug("MSDP SA %s de-referenced SPT", sa->sg_str);
+	}
+}
+
+static bool pim_msdp_sa_upstream_add_ok(struct pim_msdp_sa *sa,
+					struct pim_upstream *xg_up)
+{
+	if (!(sa->flags & PIM_MSDP_SAF_PEER)) {
+		/* SA should have been rxed from a peer */
+		return false;
+	}
+	/* check if we are RP */
+	if (!I_am_RP(sa->pim, sa->sg.grp)) {
+		return false;
+	}
+
+	/* check if we have a (*, G) with a non-empty immediate OIL */
+	if (!xg_up) {
+		pim_sgaddr sg;
+
+		memset(&sg, 0, sizeof(sg));
+		sg.grp = sa->sg.grp;
+
+		xg_up = pim_upstream_find(sa->pim, &sg);
+	}
+	if (!xg_up || (xg_up->join_state != PIM_UPSTREAM_JOINED)) {
+		/* join desired will be true for such (*, G) entries so we will
+		 * just look at join_state and let the PIM state machine do the
+		 * rest of
+		 * the magic */
+		return false;
+	}
+
+	return true;
+}
+
+/* Upstream add evaluation needs to happen everytime -
+ * 1. Peer reference is added or removed.
+ * 2. The RP for a group changes.
+ * 3. joinDesired for the associated (*, G) changes
+ * 4. associated (*, G) is removed - this seems like a bit redundant
+ *    (considering #4); but just in case an entry gets nuked without
+ *    upstream state transition
+ *    */
+static void pim_msdp_sa_upstream_update(struct pim_msdp_sa *sa,
+					struct pim_upstream *xg_up,
+					const char *ctx)
+{
+	struct pim_upstream *up;
+
+	if (!pim_msdp_sa_upstream_add_ok(sa, xg_up)) {
+		pim_msdp_sa_upstream_del(sa);
+		return;
+	}
+
+	if (sa->up) {
+		/* nothing to do */
+		return;
+	}
+
+	up = pim_upstream_find(sa->pim, &sa->sg);
+	if (up && (PIM_UPSTREAM_FLAG_TEST_SRC_MSDP(up->flags))) {
+		/* somehow we lost track of the upstream ptr? best log it */
+		sa->up = up;
+		if (PIM_DEBUG_MSDP_EVENTS) {
+			zlog_debug("MSDP SA %s SPT reference missing",
+				   sa->sg_str);
+		}
+		return;
+	}
+
+	/* RFC3618: "RP triggers a (S, G) join event towards the data source
+	 * as if a JP message was rxed addressed to the RP itself." */
+	up = pim_upstream_add(sa->pim, &sa->sg, NULL /* iif */,
+			      PIM_UPSTREAM_FLAG_MASK_SRC_MSDP, __func__, NULL);
+
+	sa->up = up;
+	if (up) {
+		/* update inherited oil */
+		pim_upstream_inherited_olist(sa->pim, up);
+		/* should we also start the kat in parallel? we will need it
+		 * when the
+		 * SA ages out */
+		if (PIM_DEBUG_MSDP_EVENTS) {
+			zlog_debug("MSDP SA %s referenced SPT", sa->sg_str);
+		}
+	} else {
+		if (PIM_DEBUG_MSDP_EVENTS) {
+			zlog_debug("MSDP SA %s SPT reference failed",
+				   sa->sg_str);
+		}
+	}
+}
+
+/* release all mem associated with a sa */
+static void pim_msdp_sa_free(struct pim_msdp_sa *sa)
+{
+	pim_msdp_sa_state_timer_setup(sa, false);
+
+	XFREE(MTYPE_PIM_MSDP_SA, sa);
+}
+
+static struct pim_msdp_sa *pim_msdp_sa_new(struct pim_instance *pim,
+					   pim_sgaddr *sg, struct in_addr rp)
+{
+	struct pim_msdp_sa *sa;
+
+	sa = XCALLOC(MTYPE_PIM_MSDP_SA, sizeof(*sa));
+
+	sa->pim = pim;
+	sa->sg = *sg;
+	snprintfrr(sa->sg_str, sizeof(sa->sg_str), "%pSG", sg);
+	sa->rp = rp;
+	sa->uptime = pim_time_monotonic_sec();
+
+	/* insert into misc tables for easy access */
+	sa = hash_get(pim->msdp.sa_hash, sa, hash_alloc_intern);
+	listnode_add_sort(pim->msdp.sa_list, sa);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		zlog_debug("MSDP SA %s created", sa->sg_str);
+	}
+
+	return sa;
+}
+
+static struct pim_msdp_sa *pim_msdp_sa_find(struct pim_instance *pim,
+					    pim_sgaddr *sg)
+{
+	struct pim_msdp_sa lookup;
+
+	lookup.sg = *sg;
+	return hash_lookup(pim->msdp.sa_hash, &lookup);
+}
+
+static struct pim_msdp_sa *pim_msdp_sa_add(struct pim_instance *pim,
+					   pim_sgaddr *sg, struct in_addr rp)
+{
+	struct pim_msdp_sa *sa;
+
+	sa = pim_msdp_sa_find(pim, sg);
+	if (sa) {
+		return sa;
+	}
+
+	return pim_msdp_sa_new(pim, sg, rp);
+}
+
+static void pim_msdp_sa_del(struct pim_msdp_sa *sa)
+{
+	/* this is somewhat redundant - still want to be careful not to leave
+	 * stale upstream references */
+	pim_msdp_sa_upstream_del(sa);
+
+	/* stop timers */
+	pim_msdp_sa_state_timer_setup(sa, false /* start */);
+
+	/* remove the entry from various tables */
+	listnode_delete(sa->pim->msdp.sa_list, sa);
+	hash_release(sa->pim->msdp.sa_hash, sa);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		zlog_debug("MSDP SA %s deleted", sa->sg_str);
+	}
+
+	/* free up any associated memory */
+	pim_msdp_sa_free(sa);
+}
+
+static void pim_msdp_sa_peer_ip_set(struct pim_msdp_sa *sa,
+				    struct pim_msdp_peer *mp, struct in_addr rp)
+{
+	struct pim_msdp_peer *old_mp;
+
+	/* optimize the "no change" case as it will happen
+	 * frequently/periodically */
+	if (mp && (sa->peer.s_addr == mp->peer.s_addr)) {
+		return;
+	}
+
+	/* any time the peer ip changes also update the rp address */
+	if (sa->peer.s_addr != INADDR_ANY) {
+		old_mp = pim_msdp_peer_find(sa->pim, sa->peer);
+		if (old_mp && old_mp->sa_cnt) {
+			--old_mp->sa_cnt;
+		}
+	}
+
+	if (mp) {
+		++mp->sa_cnt;
+		sa->peer = mp->peer;
+	} else {
+		sa->peer.s_addr = PIM_NET_INADDR_ANY;
+	}
+	sa->rp = rp;
+}
+
+/* When a local active-source is removed there is no way to withdraw the
+ * source from peers. We will simply remove it from the SA cache so it will
+ * not be sent in supsequent SA updates. Peers will consequently timeout the
+ * SA.
+ * Similarly a "peer-added" SA is never explicitly deleted. It is simply
+ * aged out overtime if not seen in the SA updates from the peers.
+ * XXX: should we provide a knob to drop entries learnt from a peer when the
+ * peer goes down? */
+static void pim_msdp_sa_deref(struct pim_msdp_sa *sa,
+			      enum pim_msdp_sa_flags flags)
+{
+	bool update_up = false;
+
+	if ((sa->flags & PIM_MSDP_SAF_LOCAL)) {
+		if (flags & PIM_MSDP_SAF_LOCAL) {
+			if (PIM_DEBUG_MSDP_EVENTS) {
+				zlog_debug("MSDP SA %s local reference removed",
+					   sa->sg_str);
+			}
+			if (sa->pim->msdp.local_cnt)
+				--sa->pim->msdp.local_cnt;
+		}
+	}
+
+	if ((sa->flags & PIM_MSDP_SAF_PEER)) {
+		if (flags & PIM_MSDP_SAF_PEER) {
+			struct in_addr rp;
+
+			if (PIM_DEBUG_MSDP_EVENTS) {
+				zlog_debug("MSDP SA %s peer reference removed",
+					   sa->sg_str);
+			}
+			pim_msdp_sa_state_timer_setup(sa, false /* start */);
+			rp.s_addr = INADDR_ANY;
+			pim_msdp_sa_peer_ip_set(sa, NULL /* mp */, rp);
+			/* if peer ref was removed we need to remove the msdp
+			 * reference on the
+			 * msdp entry */
+			update_up = true;
+		}
+	}
+
+	sa->flags &= ~flags;
+	if (update_up) {
+		pim_msdp_sa_upstream_update(sa, NULL /* xg_up */, "sa-deref");
+	}
+
+	if (!(sa->flags & PIM_MSDP_SAF_REF)) {
+		pim_msdp_sa_del(sa);
+	}
+}
+
+void pim_msdp_sa_ref(struct pim_instance *pim, struct pim_msdp_peer *mp,
+		     pim_sgaddr *sg, struct in_addr rp)
+{
+	struct pim_msdp_sa *sa;
+
+	sa = pim_msdp_sa_add(pim, sg, rp);
+	if (!sa) {
+		return;
+	}
+
+	/* reference it */
+	if (mp) {
+		if (!(sa->flags & PIM_MSDP_SAF_PEER)) {
+			sa->flags |= PIM_MSDP_SAF_PEER;
+			if (PIM_DEBUG_MSDP_EVENTS) {
+				zlog_debug("MSDP SA %s added by peer",
+					   sa->sg_str);
+			}
+		}
+		pim_msdp_sa_peer_ip_set(sa, mp, rp);
+		/* start/re-start the state timer to prevent cache expiry */
+		pim_msdp_sa_state_timer_setup(sa, true /* start */);
+		/* We re-evaluate SA "SPT-trigger" everytime we hear abt it from
+		 * a
+		 * peer. XXX: If this becomes too much of a periodic overhead we
+		 * can make it event based */
+		pim_msdp_sa_upstream_update(sa, NULL /* xg_up */, "peer-ref");
+	} else {
+		if (!(sa->flags & PIM_MSDP_SAF_LOCAL)) {
+			sa->flags |= PIM_MSDP_SAF_LOCAL;
+			++sa->pim->msdp.local_cnt;
+			if (PIM_DEBUG_MSDP_EVENTS) {
+				zlog_debug("MSDP SA %s added locally",
+					   sa->sg_str);
+			}
+			/* send an immediate SA update to peers */
+			sa->rp = pim->msdp.originator_id;
+			pim_msdp_pkt_sa_tx_one(sa);
+		}
+		sa->flags &= ~PIM_MSDP_SAF_STALE;
+	}
+}
+
+/* The following criteria must be met to originate an SA from the MSDP
+ * speaker -
+ * 1. KAT must be running i.e. source is active.
+ * 2. We must be RP for the group.
+ * 3. Source must be registrable to the RP (this is where the RFC is vague
+ *    and especially ambiguous in CLOS networks; with anycast RP all sources
+ *    are potentially registrable to all RPs in the domain). We assume #3 is
+ *    satisfied if -
+ *    a. We are also the FHR-DR for the source (OR)
+ *    b. We rxed a pim register (null or data encapsulated) within the last
+ *       (3 * (1.5 * register_suppression_timer))).
+ */
+static bool pim_msdp_sa_local_add_ok(struct pim_upstream *up)
+{
+	struct pim_instance *pim = up->channel_oil->pim;
+
+	if (!(pim->msdp.flags & PIM_MSDPF_ENABLE)) {
+		return false;
+	}
+
+	if (!pim_upstream_is_kat_running(up))
+		/* stream is not active */
+		return false;
+
+	if (!I_am_RP(pim, up->sg.grp)) {
+		/* we are not RP for the group */
+		return false;
+	}
+
+	/* we are the FHR-DR for this stream  or we are RP and have seen
+	 * registers
+	 * from a FHR for this source */
+	if (PIM_UPSTREAM_FLAG_TEST_FHR(up->flags) || up->t_msdp_reg_timer) {
+		return true;
+	}
+
+	return false;
+}
+
+static void pim_msdp_sa_local_add(struct pim_instance *pim, pim_sgaddr *sg)
+{
+	struct in_addr rp;
+	rp.s_addr = INADDR_ANY;
+	pim_msdp_sa_ref(pim, NULL /* mp */, sg, rp);
+}
+
+void pim_msdp_sa_local_del(struct pim_instance *pim, pim_sgaddr *sg)
+{
+	struct pim_msdp_sa *sa;
+
+	sa = pim_msdp_sa_find(pim, sg);
+	if (sa) {
+		pim_msdp_sa_deref(sa, PIM_MSDP_SAF_LOCAL);
+	}
+}
+
+/* we need to be very cautious with this API as SA del too can trigger an
+ * upstream del and we will get stuck in a simple loop */
+static void pim_msdp_sa_local_del_on_up_del(struct pim_instance *pim,
+					    pim_sgaddr *sg)
+{
+	struct pim_msdp_sa *sa;
+
+	sa = pim_msdp_sa_find(pim, sg);
+	if (sa) {
+		if (PIM_DEBUG_MSDP_INTERNAL) {
+			zlog_debug("MSDP local sa %s del on up del",
+				   sa->sg_str);
+		}
+
+		/* if there is no local reference escape */
+		if (!(sa->flags & PIM_MSDP_SAF_LOCAL)) {
+			if (PIM_DEBUG_MSDP_INTERNAL) {
+				zlog_debug("MSDP local sa %s del; no local ref",
+					   sa->sg_str);
+			}
+			return;
+		}
+
+		if (sa->flags & PIM_MSDP_SAF_UP_DEL_IN_PROG) {
+			/* MSDP is the one that triggered the upstream del. if
+			 * this happens
+			 * we most certainly have a bug in the PIM upstream
+			 * state machine. We
+			 * will not have a local reference unless the KAT is
+			 * running. And if the
+			 * KAT is running there MUST be an additional
+			 * source-stream reference to
+			 * the flow. Accounting for such cases requires lot of
+			 * changes; perhaps
+			 * address this in the next release? - XXX  */
+			flog_err(
+				EC_LIB_DEVELOPMENT,
+				"MSDP sa %s SPT teardown is causing the local entry to be removed",
+				sa->sg_str);
+			return;
+		}
+
+		/* we are dropping the sa on upstream del we should not have an
+		 * upstream reference */
+		if (sa->up) {
+			if (PIM_DEBUG_MSDP_INTERNAL) {
+				zlog_debug("MSDP local sa %s del; up non-NULL",
+					   sa->sg_str);
+			}
+			sa->up = NULL;
+		}
+		pim_msdp_sa_deref(sa, PIM_MSDP_SAF_LOCAL);
+	}
+}
+
+/* Local SA qualification needs to be re-evaluated when -
+ * 1. KAT is started or stopped
+ * 2. on RP changes
+ * 3. Whenever FHR status changes for a (S,G) - XXX - currently there
+ *    is no clear path to transition an entry out of "MASK_FHR" need
+ *    to discuss this with Donald. May result in some strangeness if the
+ *    FHR is also the RP.
+ * 4. When msdp_reg timer is started or stopped
+ */
+void pim_msdp_sa_local_update(struct pim_upstream *up)
+{
+	struct pim_instance *pim = up->channel_oil->pim;
+
+	if (pim_msdp_sa_local_add_ok(up)) {
+		pim_msdp_sa_local_add(pim, &up->sg);
+	} else {
+		pim_msdp_sa_local_del(pim, &up->sg);
+	}
+}
+
+static void pim_msdp_sa_local_setup(struct pim_instance *pim)
+{
+	struct pim_upstream *up;
+
+	frr_each (rb_pim_upstream, &pim->upstream_head, up)
+		pim_msdp_sa_local_update(up);
+}
+
+/* whenever the RP changes we need to re-evaluate the "local" SA-cache */
+/* XXX: needs to be tested */
+void pim_msdp_i_am_rp_changed(struct pim_instance *pim)
+{
+	struct listnode *sanode;
+	struct listnode *nextnode;
+	struct pim_msdp_sa *sa;
+
+	if (!(pim->msdp.flags & PIM_MSDPF_ENABLE)) {
+		/* if the feature is not enabled do nothing */
+		return;
+	}
+
+	if (PIM_DEBUG_MSDP_INTERNAL) {
+		zlog_debug("MSDP i_am_rp changed");
+	}
+
+	/* mark all local entries as stale */
+	for (ALL_LIST_ELEMENTS_RO(pim->msdp.sa_list, sanode, sa)) {
+		if (sa->flags & PIM_MSDP_SAF_LOCAL) {
+			sa->flags |= PIM_MSDP_SAF_STALE;
+		}
+	}
+
+	/* re-setup local SA entries */
+	pim_msdp_sa_local_setup(pim);
+
+	for (ALL_LIST_ELEMENTS(pim->msdp.sa_list, sanode, nextnode, sa)) {
+		/* purge stale SA entries */
+		if (sa->flags & PIM_MSDP_SAF_STALE) {
+			/* clear the stale flag; the entry may be kept even
+			 * after
+			 * "local-deref" */
+			sa->flags &= ~PIM_MSDP_SAF_STALE;
+			/* sa_deref can end up freeing the sa; so don't access
+			 * contents after */
+			pim_msdp_sa_deref(sa, PIM_MSDP_SAF_LOCAL);
+		} else {
+			/* if the souce is still active check if we can
+			 * influence SPT */
+			pim_msdp_sa_upstream_update(sa, NULL /* xg_up */,
+						    "rp-change");
+		}
+	}
+}
+
+/* We track the join state of (*, G) entries. If G has sources in the SA-cache
+ * we need to setup or teardown SPT when the JoinDesired status changes for
+ * (*, G) */
+void pim_msdp_up_join_state_changed(struct pim_instance *pim,
+				    struct pim_upstream *xg_up)
+{
+	struct listnode *sanode;
+	struct pim_msdp_sa *sa;
+
+	if (PIM_DEBUG_MSDP_INTERNAL) {
+		zlog_debug("MSDP join state changed for %s", xg_up->sg_str);
+	}
+
+	/* If this is not really an XG entry just move on */
+	if (!pim_addr_is_any(xg_up->sg.src) || pim_addr_is_any(xg_up->sg.grp)) {
+		return;
+	}
+
+	/* XXX: Need to maintain SAs per-group to avoid all this unnecessary
+	 * walking */
+	for (ALL_LIST_ELEMENTS_RO(pim->msdp.sa_list, sanode, sa)) {
+		if (pim_addr_cmp(sa->sg.grp, xg_up->sg.grp)) {
+			continue;
+		}
+		pim_msdp_sa_upstream_update(sa, xg_up, "up-jp-change");
+	}
+}
+
+static void pim_msdp_up_xg_del(struct pim_instance *pim, pim_sgaddr *sg)
+{
+	struct listnode *sanode;
+	struct pim_msdp_sa *sa;
+
+	if (PIM_DEBUG_MSDP_INTERNAL) {
+		zlog_debug("MSDP %pSG del", sg);
+	}
+
+	/* If this is not really an XG entry just move on */
+	if (!pim_addr_is_any(sg->src) || pim_addr_is_any(sg->grp)) {
+		return;
+	}
+
+	/* XXX: Need to maintain SAs per-group to avoid all this unnecessary
+	 * walking */
+	for (ALL_LIST_ELEMENTS_RO(pim->msdp.sa_list, sanode, sa)) {
+		if (pim_addr_cmp(sa->sg.grp, sg->grp)) {
+			continue;
+		}
+		pim_msdp_sa_upstream_update(sa, NULL /* xg */, "up-jp-change");
+	}
+}
+
+void pim_msdp_up_del(struct pim_instance *pim, pim_sgaddr *sg)
+{
+	if (PIM_DEBUG_MSDP_INTERNAL) {
+		zlog_debug("MSDP up %pSG del", sg);
+	}
+	if (pim_addr_is_any(sg->src)) {
+		pim_msdp_up_xg_del(pim, sg);
+	} else {
+		pim_msdp_sa_local_del_on_up_del(pim, sg);
+	}
+}
+
+/* sa hash and peer list helpers */
+static unsigned int pim_msdp_sa_hash_key_make(const void *p)
+{
+	const struct pim_msdp_sa *sa = p;
+
+	return pim_sgaddr_hash(sa->sg, 0);
+}
+
+static bool pim_msdp_sa_hash_eq(const void *p1, const void *p2)
+{
+	const struct pim_msdp_sa *sa1 = p1;
+	const struct pim_msdp_sa *sa2 = p2;
+
+	return !pim_sgaddr_cmp(sa1->sg, sa2->sg);
+}
+
+static int pim_msdp_sa_comp(const void *p1, const void *p2)
+{
+	const struct pim_msdp_sa *sa1 = p1;
+	const struct pim_msdp_sa *sa2 = p2;
+
+	return pim_sgaddr_cmp(sa1->sg, sa2->sg);
+}
+
+/* RFC-3618:Sec-10.1.3 - Peer-RPF forwarding */
+/* XXX: this can use a bit of refining and extensions */
+bool pim_msdp_peer_rpf_check(struct pim_msdp_peer *mp, struct in_addr rp)
+{
+	struct pim_nexthop nexthop = {0};
+
+	if (mp->peer.s_addr == rp.s_addr) {
+		return true;
+	}
+
+	/* check if the MSDP peer is the nexthop for the RP */
+	if (pim_nexthop_lookup(mp->pim, &nexthop, rp, 0) &&
+	    nexthop.mrib_nexthop_addr.s_addr == mp->peer.s_addr) {
+		return true;
+	}
+
+	return false;
+}
+
+/************************ Peer session management **************************/
+char *pim_msdp_state_dump(enum pim_msdp_peer_state state, char *buf,
+			  int buf_size)
+{
+	switch (state) {
+	case PIM_MSDP_DISABLED:
+		snprintf(buf, buf_size, "%s", "disabled");
+		break;
+	case PIM_MSDP_INACTIVE:
+		snprintf(buf, buf_size, "%s", "inactive");
+		break;
+	case PIM_MSDP_LISTEN:
+		snprintf(buf, buf_size, "%s", "listen");
+		break;
+	case PIM_MSDP_CONNECTING:
+		snprintf(buf, buf_size, "%s", "connecting");
+		break;
+	case PIM_MSDP_ESTABLISHED:
+		snprintf(buf, buf_size, "%s", "established");
+		break;
+	default:
+		snprintf(buf, buf_size, "unk-%d", state);
+	}
+	return buf;
+}
+
+static void pim_msdp_peer_state_chg_log(struct pim_msdp_peer *mp)
+{
+	char state_str[PIM_MSDP_STATE_STRLEN];
+
+	pim_msdp_state_dump(mp->state, state_str, sizeof(state_str));
+	zlog_debug("MSDP peer %s state chg to %s", mp->key_str, state_str);
+}
+
+/* MSDP Connection State Machine actions (defined in RFC-3618:Sec-11.2) */
+/* 11.2.A2: active peer - start connect retry timer; when the timer fires
+ * a tcp connection will be made */
+static void pim_msdp_peer_connect(struct pim_msdp_peer *mp)
+{
+	mp->state = PIM_MSDP_CONNECTING;
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		pim_msdp_peer_state_chg_log(mp);
+	}
+
+	pim_msdp_peer_cr_timer_setup(mp, true /* start */);
+}
+
+/* 11.2.A3: passive peer - just listen for connections */
+static void pim_msdp_peer_listen(struct pim_msdp_peer *mp)
+{
+	mp->state = PIM_MSDP_LISTEN;
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		pim_msdp_peer_state_chg_log(mp);
+	}
+
+	/* this is interntionally asymmetric i.e. we set up listen-socket when
+	* the
+	* first listening peer is configured; but don't bother tearing it down
+	* when
+	* all the peers go down */
+	pim_msdp_sock_listen(mp->pim);
+}
+
+/* 11.2.A4 and 11.2.A5: transition active or passive peer to
+ * established state */
+void pim_msdp_peer_established(struct pim_msdp_peer *mp)
+{
+	if (mp->state != PIM_MSDP_ESTABLISHED) {
+		++mp->est_flaps;
+	}
+
+	mp->state = PIM_MSDP_ESTABLISHED;
+	mp->uptime = pim_time_monotonic_sec();
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		pim_msdp_peer_state_chg_log(mp);
+	}
+
+	/* stop retry timer on active peers */
+	pim_msdp_peer_cr_timer_setup(mp, false /* start */);
+
+	/* send KA; start KA and hold timers */
+	pim_msdp_pkt_ka_tx(mp);
+	pim_msdp_peer_ka_timer_setup(mp, true /* start */);
+	pim_msdp_peer_hold_timer_setup(mp, true /* start */);
+
+	pim_msdp_pkt_sa_tx_to_one_peer(mp);
+
+	PIM_MSDP_PEER_WRITE_ON(mp);
+	PIM_MSDP_PEER_READ_ON(mp);
+}
+
+/* 11.2.A6, 11.2.A7 and 11.2.A8: shutdown the peer tcp connection */
+void pim_msdp_peer_stop_tcp_conn(struct pim_msdp_peer *mp, bool chg_state)
+{
+	if (chg_state) {
+		if (mp->state == PIM_MSDP_ESTABLISHED) {
+			++mp->est_flaps;
+		}
+		mp->state = PIM_MSDP_INACTIVE;
+		if (PIM_DEBUG_MSDP_EVENTS) {
+			pim_msdp_peer_state_chg_log(mp);
+		}
+	}
+
+	if (PIM_DEBUG_MSDP_INTERNAL) {
+		zlog_debug("MSDP peer %s pim_msdp_peer_stop_tcp_conn",
+			   mp->key_str);
+	}
+	/* stop read and write threads */
+	PIM_MSDP_PEER_READ_OFF(mp);
+	PIM_MSDP_PEER_WRITE_OFF(mp);
+
+	/* reset buffers */
+	mp->packet_size = 0;
+	if (mp->ibuf)
+		stream_reset(mp->ibuf);
+	if (mp->obuf)
+		stream_fifo_clean(mp->obuf);
+
+	/* stop all peer timers */
+	pim_msdp_peer_ka_timer_setup(mp, false /* start */);
+	pim_msdp_peer_cr_timer_setup(mp, false /* start */);
+	pim_msdp_peer_hold_timer_setup(mp, false /* start */);
+
+	/* close connection */
+	if (mp->fd >= 0) {
+		close(mp->fd);
+		mp->fd = -1;
+	}
+}
+
+/* RFC-3618:Sec-5.6 - stop the peer tcp connection and startover */
+void pim_msdp_peer_reset_tcp_conn(struct pim_msdp_peer *mp, const char *rc_str)
+{
+	if (PIM_DEBUG_EVENTS) {
+		zlog_debug("MSDP peer %s tcp reset %s", mp->key_str, rc_str);
+		snprintf(mp->last_reset, sizeof(mp->last_reset), "%s", rc_str);
+	}
+
+	/* close the connection and transition to listening or connecting */
+	pim_msdp_peer_stop_tcp_conn(mp, true /* chg_state */);
+	if (PIM_MSDP_PEER_IS_LISTENER(mp)) {
+		pim_msdp_peer_listen(mp);
+	} else {
+		pim_msdp_peer_connect(mp);
+	}
+}
+
+static void pim_msdp_peer_timer_expiry_log(struct pim_msdp_peer *mp,
+					   const char *timer_str)
+{
+	zlog_debug("MSDP peer %s %s timer expired", mp->key_str, timer_str);
+}
+
+/* RFC-3618:Sec-5.4 - peer hold timer */
+static void pim_msdp_peer_hold_timer_cb(struct thread *t)
+{
+	struct pim_msdp_peer *mp;
+
+	mp = THREAD_ARG(t);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		pim_msdp_peer_timer_expiry_log(mp, "hold");
+	}
+
+	if (mp->state != PIM_MSDP_ESTABLISHED) {
+		return;
+	}
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		pim_msdp_peer_state_chg_log(mp);
+	}
+	pim_msdp_peer_reset_tcp_conn(mp, "ht-expired");
+}
+
+static void pim_msdp_peer_hold_timer_setup(struct pim_msdp_peer *mp, bool start)
+{
+	struct pim_instance *pim = mp->pim;
+	THREAD_OFF(mp->hold_timer);
+	if (start) {
+		thread_add_timer(pim->msdp.master, pim_msdp_peer_hold_timer_cb,
+				 mp, pim->msdp.hold_time, &mp->hold_timer);
+	}
+}
+
+
+/* RFC-3618:Sec-5.5 - peer keepalive timer */
+static void pim_msdp_peer_ka_timer_cb(struct thread *t)
+{
+	struct pim_msdp_peer *mp;
+
+	mp = THREAD_ARG(t);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		pim_msdp_peer_timer_expiry_log(mp, "ka");
+	}
+
+	pim_msdp_pkt_ka_tx(mp);
+	pim_msdp_peer_ka_timer_setup(mp, true /* start */);
+}
+
+static void pim_msdp_peer_ka_timer_setup(struct pim_msdp_peer *mp, bool start)
+{
+	THREAD_OFF(mp->ka_timer);
+	if (start) {
+		thread_add_timer(mp->pim->msdp.master,
+				 pim_msdp_peer_ka_timer_cb, mp,
+				 mp->pim->msdp.keep_alive, &mp->ka_timer);
+	}
+}
+
+static void pim_msdp_peer_active_connect(struct pim_msdp_peer *mp)
+{
+	int rc;
+	++mp->conn_attempts;
+	rc = pim_msdp_sock_connect(mp);
+
+	if (PIM_DEBUG_MSDP_INTERNAL) {
+		zlog_debug("MSDP peer %s pim_msdp_peer_active_connect: %d",
+			   mp->key_str, rc);
+	}
+
+	switch (rc) {
+	case connect_error:
+	case -1:
+		/* connect failed restart the connect-retry timer */
+		pim_msdp_peer_cr_timer_setup(mp, true /* start */);
+		break;
+
+	case connect_success:
+		/* connect was sucessful move to established */
+		pim_msdp_peer_established(mp);
+		break;
+
+	case connect_in_progress:
+		/* for NB content we need to wait till sock is readable or
+		 * writeable */
+		PIM_MSDP_PEER_WRITE_ON(mp);
+		PIM_MSDP_PEER_READ_ON(mp);
+		/* also restart connect-retry timer to reset the socket if
+		 * connect is
+		 * not sucessful */
+		pim_msdp_peer_cr_timer_setup(mp, true /* start */);
+		break;
+	}
+}
+
+/* RFC-3618:Sec-5.6 - connection retry on active peer */
+static void pim_msdp_peer_cr_timer_cb(struct thread *t)
+{
+	struct pim_msdp_peer *mp;
+
+	mp = THREAD_ARG(t);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		pim_msdp_peer_timer_expiry_log(mp, "connect-retry");
+	}
+
+	if (mp->state != PIM_MSDP_CONNECTING || PIM_MSDP_PEER_IS_LISTENER(mp)) {
+		return;
+	}
+
+	pim_msdp_peer_active_connect(mp);
+}
+
+static void pim_msdp_peer_cr_timer_setup(struct pim_msdp_peer *mp, bool start)
+{
+	THREAD_OFF(mp->cr_timer);
+	if (start) {
+		thread_add_timer(mp->pim->msdp.master,
+				 pim_msdp_peer_cr_timer_cb, mp,
+				 mp->pim->msdp.connection_retry, &mp->cr_timer);
+	}
+}
+
+/* if a valid packet is rxed from the peer we can restart hold timer */
+void pim_msdp_peer_pkt_rxed(struct pim_msdp_peer *mp)
+{
+	if (mp->state == PIM_MSDP_ESTABLISHED) {
+		pim_msdp_peer_hold_timer_setup(mp, true /* start */);
+	}
+}
+
+/* if a valid packet is txed to the peer we can restart ka timer and avoid
+ * unnecessary ka noise in the network */
+void pim_msdp_peer_pkt_txed(struct pim_msdp_peer *mp)
+{
+	if (mp->state == PIM_MSDP_ESTABLISHED) {
+		pim_msdp_peer_ka_timer_setup(mp, true /* start */);
+		if (PIM_DEBUG_MSDP_INTERNAL) {
+			zlog_debug("MSDP ka timer restart on pkt tx to %s",
+				   mp->key_str);
+		}
+	}
+}
+
+static void pim_msdp_addr2su(union sockunion *su, struct in_addr addr)
+{
+	sockunion_init(su);
+	su->sin.sin_addr = addr;
+	su->sin.sin_family = AF_INET;
+#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
+	su->sin.sin_len = sizeof(struct sockaddr_in);
+#endif /* HAVE_STRUCT_SOCKADDR_IN_SIN_LEN */
+}
+
+/* 11.2.A1: create a new peer and transition state to listen or connecting */
+struct pim_msdp_peer *pim_msdp_peer_add(struct pim_instance *pim,
+					const struct in_addr *peer,
+					const struct in_addr *local,
+					const char *mesh_group_name)
+{
+	struct pim_msdp_peer *mp;
+
+	pim_msdp_enable(pim);
+
+	mp = XCALLOC(MTYPE_PIM_MSDP_PEER, sizeof(*mp));
+
+	mp->pim = pim;
+	mp->peer = *peer;
+	pim_inet4_dump("<peer?>", mp->peer, mp->key_str, sizeof(mp->key_str));
+	pim_msdp_addr2su(&mp->su_peer, mp->peer);
+	mp->local = *local;
+	/* XXX: originator_id setting needs to move to the mesh group */
+	pim->msdp.originator_id = *local;
+	pim_msdp_addr2su(&mp->su_local, mp->local);
+	if (mesh_group_name)
+		mp->mesh_group_name =
+			XSTRDUP(MTYPE_PIM_MSDP_MG_NAME, mesh_group_name);
+
+	mp->state = PIM_MSDP_INACTIVE;
+	mp->fd = -1;
+	strlcpy(mp->last_reset, "-", sizeof(mp->last_reset));
+	/* higher IP address is listener */
+	if (ntohl(mp->local.s_addr) > ntohl(mp->peer.s_addr)) {
+		mp->flags |= PIM_MSDP_PEERF_LISTENER;
+	}
+
+	/* setup packet buffers */
+	mp->ibuf = stream_new(PIM_MSDP_MAX_PACKET_SIZE);
+	mp->obuf = stream_fifo_new();
+
+	/* insert into misc tables for easy access */
+	mp = hash_get(pim->msdp.peer_hash, mp, hash_alloc_intern);
+	listnode_add_sort(pim->msdp.peer_list, mp);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		zlog_debug("MSDP peer %s created", mp->key_str);
+
+		pim_msdp_peer_state_chg_log(mp);
+	}
+
+	/* fireup the connect state machine */
+	if (PIM_MSDP_PEER_IS_LISTENER(mp)) {
+		pim_msdp_peer_listen(mp);
+	} else {
+		pim_msdp_peer_connect(mp);
+	}
+	return mp;
+}
+
+struct pim_msdp_peer *pim_msdp_peer_find(struct pim_instance *pim,
+					 struct in_addr peer_addr)
+{
+	struct pim_msdp_peer lookup;
+
+	lookup.peer = peer_addr;
+	return hash_lookup(pim->msdp.peer_hash, &lookup);
+}
+
+/* release all mem associated with a peer */
+static void pim_msdp_peer_free(struct pim_msdp_peer *mp)
+{
+	/*
+	 * Let's make sure we are not running when we delete
+	 * the underlying data structure
+	 */
+	pim_msdp_peer_stop_tcp_conn(mp, false);
+
+	if (mp->ibuf) {
+		stream_free(mp->ibuf);
+	}
+
+	if (mp->obuf) {
+		stream_fifo_free(mp->obuf);
+	}
+
+	XFREE(MTYPE_PIM_MSDP_MG_NAME, mp->mesh_group_name);
+
+	mp->pim = NULL;
+	XFREE(MTYPE_PIM_MSDP_PEER, mp);
+}
+
+/* delete the peer config */
+void pim_msdp_peer_del(struct pim_msdp_peer **mp)
+{
+	if (*mp == NULL)
+		return;
+
+	/* stop the tcp connection and shutdown all timers */
+	pim_msdp_peer_stop_tcp_conn(*mp, true /* chg_state */);
+
+	/* remove the session from various tables */
+	listnode_delete((*mp)->pim->msdp.peer_list, *mp);
+	hash_release((*mp)->pim->msdp.peer_hash, *mp);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		zlog_debug("MSDP peer %s deleted", (*mp)->key_str);
+	}
+
+	/* free up any associated memory */
+	pim_msdp_peer_free(*mp);
+	*mp = NULL;
+}
+
+void pim_msdp_peer_change_source(struct pim_msdp_peer *mp,
+				 const struct in_addr *addr)
+{
+	pim_msdp_peer_stop_tcp_conn(mp, true);
+
+	mp->local = *addr;
+
+	if (PIM_MSDP_PEER_IS_LISTENER(mp))
+		pim_msdp_peer_listen(mp);
+	else
+		pim_msdp_peer_connect(mp);
+}
+
+/* peer hash and peer list helpers */
+static unsigned int pim_msdp_peer_hash_key_make(const void *p)
+{
+	const struct pim_msdp_peer *mp = p;
+	return (jhash_1word(mp->peer.s_addr, 0));
+}
+
+static bool pim_msdp_peer_hash_eq(const void *p1, const void *p2)
+{
+	const struct pim_msdp_peer *mp1 = p1;
+	const struct pim_msdp_peer *mp2 = p2;
+
+	return (mp1->peer.s_addr == mp2->peer.s_addr);
+}
+
+static int pim_msdp_peer_comp(const void *p1, const void *p2)
+{
+	const struct pim_msdp_peer *mp1 = p1;
+	const struct pim_msdp_peer *mp2 = p2;
+
+	if (ntohl(mp1->peer.s_addr) < ntohl(mp2->peer.s_addr))
+		return -1;
+
+	if (ntohl(mp1->peer.s_addr) > ntohl(mp2->peer.s_addr))
+		return 1;
+
+	return 0;
+}
+
+/************************** Mesh group management **************************/
+void pim_msdp_mg_free(struct pim_instance *pim, struct pim_msdp_mg **mgp)
+{
+	struct pim_msdp_mg_mbr *mbr;
+	struct listnode *n, *nn;
+
+	if (*mgp == NULL)
+		return;
+
+	/* SIP is being removed - tear down all active peer sessions */
+	for (ALL_LIST_ELEMENTS((*mgp)->mbr_list, n, nn, mbr))
+		pim_msdp_mg_mbr_del((*mgp), mbr);
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		zlog_debug("MSDP mesh-group %s deleted",
+			   (*mgp)->mesh_group_name);
+	}
+
+	XFREE(MTYPE_PIM_MSDP_MG_NAME, (*mgp)->mesh_group_name);
+
+	if ((*mgp)->mbr_list)
+		list_delete(&(*mgp)->mbr_list);
+
+	SLIST_REMOVE(&pim->msdp.mglist, (*mgp), pim_msdp_mg, mg_entry);
+	XFREE(MTYPE_PIM_MSDP_MG, (*mgp));
+}
+
+struct pim_msdp_mg *pim_msdp_mg_new(struct pim_instance *pim,
+				    const char *mesh_group_name)
+{
+	struct pim_msdp_mg *mg;
+
+	mg = XCALLOC(MTYPE_PIM_MSDP_MG, sizeof(*mg));
+
+	mg->mesh_group_name = XSTRDUP(MTYPE_PIM_MSDP_MG_NAME, mesh_group_name);
+	mg->mbr_list = list_new();
+	mg->mbr_list->del = (void (*)(void *))pim_msdp_mg_mbr_free;
+	mg->mbr_list->cmp = (int (*)(void *, void *))pim_msdp_mg_mbr_comp;
+
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		zlog_debug("MSDP mesh-group %s created", mg->mesh_group_name);
+	}
+
+	SLIST_INSERT_HEAD(&pim->msdp.mglist, mg, mg_entry);
+
+	return mg;
+}
+
+static int pim_msdp_mg_mbr_comp(const void *p1, const void *p2)
+{
+	const struct pim_msdp_mg_mbr *mbr1 = p1;
+	const struct pim_msdp_mg_mbr *mbr2 = p2;
+
+	if (ntohl(mbr1->mbr_ip.s_addr) < ntohl(mbr2->mbr_ip.s_addr))
+		return -1;
+
+	if (ntohl(mbr1->mbr_ip.s_addr) > ntohl(mbr2->mbr_ip.s_addr))
+		return 1;
+
+	return 0;
+}
+
+static void pim_msdp_mg_mbr_free(struct pim_msdp_mg_mbr *mbr)
+{
+	XFREE(MTYPE_PIM_MSDP_MG_MBR, mbr);
+}
+
+void pim_msdp_mg_mbr_del(struct pim_msdp_mg *mg, struct pim_msdp_mg_mbr *mbr)
+{
+	/* Delete active peer session if any */
+	if (mbr->mp) {
+		pim_msdp_peer_del(&mbr->mp);
+	}
+
+	listnode_delete(mg->mbr_list, mbr);
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		char ip_str[INET_ADDRSTRLEN];
+		pim_inet4_dump("<mbr?>", mbr->mbr_ip, ip_str, sizeof(ip_str));
+		zlog_debug("MSDP mesh-group %s mbr %s deleted",
+			   mg->mesh_group_name, ip_str);
+	}
+	pim_msdp_mg_mbr_free(mbr);
+	if (mg->mbr_cnt) {
+		--mg->mbr_cnt;
+	}
+}
+
+static void pim_msdp_src_del(struct pim_msdp_mg *mg)
+{
+	struct pim_msdp_mg_mbr *mbr;
+	struct listnode *mbr_node;
+
+	/* SIP is being removed - tear down all active peer sessions */
+	for (ALL_LIST_ELEMENTS_RO(mg->mbr_list, mbr_node, mbr)) {
+		if (mbr->mp)
+			pim_msdp_peer_del(&mbr->mp);
+	}
+	if (PIM_DEBUG_MSDP_EVENTS) {
+		zlog_debug("MSDP mesh-group %s src cleared",
+			   mg->mesh_group_name);
+	}
+}
+
+/*********************** MSDP feature APIs *********************************/
+int pim_msdp_config_write(struct pim_instance *pim, struct vty *vty,
+			  const char *spaces)
+{
+	struct pim_msdp_mg *mg;
+	struct listnode *mbrnode;
+	struct pim_msdp_mg_mbr *mbr;
+	char src_str[INET_ADDRSTRLEN];
+	int count = 0;
+
+	if (SLIST_EMPTY(&pim->msdp.mglist))
+		return count;
+
+	SLIST_FOREACH (mg, &pim->msdp.mglist, mg_entry) {
+		if (mg->src_ip.s_addr != INADDR_ANY) {
+			pim_inet4_dump("<src?>", mg->src_ip, src_str,
+				       sizeof(src_str));
+			vty_out(vty, "%sip msdp mesh-group %s source %s\n",
+				spaces, mg->mesh_group_name, src_str);
+			++count;
+		}
+
+		for (ALL_LIST_ELEMENTS_RO(mg->mbr_list, mbrnode, mbr)) {
+			vty_out(vty, "%sip msdp mesh-group %s member %pI4\n",
+				spaces, mg->mesh_group_name, &mbr->mbr_ip);
+			++count;
+		}
+	}
+
+	return count;
+}
+
+bool pim_msdp_peer_config_write(struct vty *vty, struct pim_instance *pim,
+				const char *spaces)
+{
+	struct pim_msdp_peer *mp;
+	struct listnode *node;
+	bool written = false;
+
+	for (ALL_LIST_ELEMENTS_RO(pim->msdp.peer_list, node, mp)) {
+		/* Skip meshed group peers. */
+		if (mp->flags & PIM_MSDP_PEERF_IN_GROUP)
+			continue;
+
+		vty_out(vty, "%sip msdp peer %pI4 source %pI4\n", spaces,
+			&mp->peer, &mp->local);
+		written = true;
+	}
+
+	return written;
+}
+
+/* Enable feature including active/periodic timers etc. on the first peer
+ * config. Till then MSDP should just stay quiet. */
+static void pim_msdp_enable(struct pim_instance *pim)
+{
+	if (pim->msdp.flags & PIM_MSDPF_ENABLE) {
+		/* feature is already enabled */
+		return;
+	}
+	pim->msdp.flags |= PIM_MSDPF_ENABLE;
+	pim->msdp.work_obuf = stream_new(PIM_MSDP_MAX_PACKET_SIZE);
+	pim_msdp_sa_adv_timer_setup(pim, true /* start */);
+	/* setup sa cache based on local sources */
+	pim_msdp_sa_local_setup(pim);
+}
+
+/* MSDP init */
+void pim_msdp_init(struct pim_instance *pim, struct thread_master *master)
+{
+	pim->msdp.master = master;
+	char hash_name[64];
+
+	snprintf(hash_name, sizeof(hash_name), "PIM %s MSDP Peer Hash",
+		 pim->vrf->name);
+	pim->msdp.peer_hash = hash_create(pim_msdp_peer_hash_key_make,
+					  pim_msdp_peer_hash_eq, hash_name);
+	pim->msdp.peer_list = list_new();
+	pim->msdp.peer_list->del = (void (*)(void *))pim_msdp_peer_free;
+	pim->msdp.peer_list->cmp = (int (*)(void *, void *))pim_msdp_peer_comp;
+
+	snprintf(hash_name, sizeof(hash_name), "PIM %s MSDP SA Hash",
+		 pim->vrf->name);
+	pim->msdp.sa_hash = hash_create(pim_msdp_sa_hash_key_make,
+					pim_msdp_sa_hash_eq, hash_name);
+	pim->msdp.sa_list = list_new();
+	pim->msdp.sa_list->del = (void (*)(void *))pim_msdp_sa_free;
+	pim->msdp.sa_list->cmp = (int (*)(void *, void *))pim_msdp_sa_comp;
+}
+
+/* counterpart to MSDP init; XXX: unused currently */
+void pim_msdp_exit(struct pim_instance *pim)
+{
+	struct pim_msdp_mg *mg;
+
+	pim_msdp_sa_adv_timer_setup(pim, false);
+
+	/* Stop listener and delete all peer sessions */
+	while ((mg = SLIST_FIRST(&pim->msdp.mglist)) != NULL)
+		pim_msdp_mg_free(pim, &mg);
+
+	if (pim->msdp.peer_hash) {
+		hash_clean(pim->msdp.peer_hash, NULL);
+		hash_free(pim->msdp.peer_hash);
+		pim->msdp.peer_hash = NULL;
+	}
+
+	if (pim->msdp.peer_list) {
+		list_delete(&pim->msdp.peer_list);
+	}
+
+	if (pim->msdp.sa_hash) {
+		hash_clean(pim->msdp.sa_hash, NULL);
+		hash_free(pim->msdp.sa_hash);
+		pim->msdp.sa_hash = NULL;
+	}
+
+	if (pim->msdp.sa_list) {
+		list_delete(&pim->msdp.sa_list);
+	}
+
+	if (pim->msdp.work_obuf)
+		stream_free(pim->msdp.work_obuf);
+	pim->msdp.work_obuf = NULL;
+}
+
+void pim_msdp_mg_src_add(struct pim_instance *pim, struct pim_msdp_mg *mg,
+			 struct in_addr *ai)
+{
+	struct pim_msdp_mg_mbr *mbr;
+	struct listnode *mbr_node;
+
+	/* Stop all connections and remove data structures. */
+	pim_msdp_src_del(mg);
+
+	/* Set new address. */
+	mg->src_ip = *ai;
+
+	/* No new address, disable everyone. */
+	if (ai->s_addr == INADDR_ANY) {
+		if (PIM_DEBUG_MSDP_EVENTS)
+			zlog_debug("MSDP mesh-group %s src unset",
+				   mg->mesh_group_name);
+		return;
+	}
+
+	/* Create data structures and start TCP connection. */
+	for (ALL_LIST_ELEMENTS_RO(mg->mbr_list, mbr_node, mbr))
+		mbr->mp = pim_msdp_peer_add(pim, &mbr->mbr_ip, &mg->src_ip,
+					    mg->mesh_group_name);
+
+	if (PIM_DEBUG_MSDP_EVENTS)
+		zlog_debug("MSDP mesh-group %s src %pI4 set",
+			   mg->mesh_group_name, &mg->src_ip);
+}
+
+struct pim_msdp_mg_mbr *pim_msdp_mg_mbr_add(struct pim_instance *pim,
+					    struct pim_msdp_mg *mg,
+					    struct in_addr *ia)
+{
+	struct pim_msdp_mg_mbr *mbr;
+
+	mbr = XCALLOC(MTYPE_PIM_MSDP_MG_MBR, sizeof(*mbr));
+	mbr->mbr_ip = *ia;
+	listnode_add_sort(mg->mbr_list, mbr);
+
+	/* if valid SIP has been configured add peer session */
+	if (mg->src_ip.s_addr != INADDR_ANY)
+		mbr->mp = pim_msdp_peer_add(pim, &mbr->mbr_ip, &mg->src_ip,
+					    mg->mesh_group_name);
+
+	if (PIM_DEBUG_MSDP_EVENTS)
+		zlog_debug("MSDP mesh-group %s mbr %pI4 created",
+			   mg->mesh_group_name, &mbr->mbr_ip);
+
+	++mg->mbr_cnt;
+
+	return mbr;
+}