1 files changed, 395 insertions, 0 deletions

diff --git a/pimd/pim_rpf.c b/pimd/pim_rpf.c
new file mode 100644
index 0000000..b17ae31
--- /dev/null
+++ b/pimd/pim_rpf.c
@@ -0,0 +1,395 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PIM for Quagga
+ * Copyright (C) 2008  Everton da Silva Marques
+ */
+
+#include <zebra.h>
+
+#include "if.h"
+
+#include "log.h"
+#include "prefix.h"
+#include "memory.h"
+#include "jhash.h"
+
+#include "pimd.h"
+#include "pim_instance.h"
+#include "pim_rpf.h"
+#include "pim_pim.h"
+#include "pim_str.h"
+#include "pim_iface.h"
+#include "pim_neighbor.h"
+#include "pim_zlookup.h"
+#include "pim_ifchannel.h"
+#include "pim_time.h"
+#include "pim_nht.h"
+#include "pim_oil.h"
+#include "pim_mlag.h"
+
+static pim_addr pim_rpf_find_rpf_addr(struct pim_upstream *up);
+
+void pim_rpf_set_refresh_time(struct pim_instance *pim)
+{
+	pim->last_route_change_time = pim_time_monotonic_usec();
+	if (PIM_DEBUG_PIM_TRACE)
+		zlog_debug("%s: vrf(%s) New last route change time: %" PRId64,
+			   __func__, pim->vrf->name,
+			   pim->last_route_change_time);
+}
+
+bool pim_nexthop_lookup(struct pim_instance *pim, struct pim_nexthop *nexthop,
+			pim_addr addr, int neighbor_needed)
+{
+	struct pim_zlookup_nexthop nexthop_tab[router->multipath];
+	struct pim_neighbor *nbr = NULL;
+	int num_ifindex;
+	struct interface *ifp = NULL;
+	ifindex_t first_ifindex = 0;
+	int found = 0;
+	int i = 0;
+	struct pim_interface *pim_ifp;
+
+#if PIM_IPV == 4
+	/*
+	 * We should not attempt to lookup a
+	 * 255.255.255.255 address, since
+	 * it will never work
+	 */
+	if (pim_addr_is_any(addr))
+		return false;
+#endif
+
+	if ((!pim_addr_cmp(nexthop->last_lookup, addr)) &&
+	    (nexthop->last_lookup_time > pim->last_route_change_time)) {
+		if (PIM_DEBUG_PIM_NHT)
+			zlog_debug(
+				"%s: Using last lookup for %pPAs at %lld, %" PRId64
+				" addr %pPAs",
+				__func__, &addr, nexthop->last_lookup_time,
+				pim->last_route_change_time,
+				&nexthop->mrib_nexthop_addr);
+		pim->nexthop_lookups_avoided++;
+		return true;
+	} else {
+		if (PIM_DEBUG_PIM_NHT)
+			zlog_debug(
+				"%s: Looking up: %pPAs, last lookup time: %lld, %" PRId64,
+				__func__, &addr, nexthop->last_lookup_time,
+				pim->last_route_change_time);
+	}
+
+	memset(nexthop_tab, 0,
+	       sizeof(struct pim_zlookup_nexthop) * router->multipath);
+	num_ifindex =
+		zclient_lookup_nexthop(pim, nexthop_tab, router->multipath,
+				       addr, PIM_NEXTHOP_LOOKUP_MAX);
+	if (num_ifindex < 1) {
+		if (PIM_DEBUG_PIM_NHT)
+			zlog_debug(
+				"%s %s: could not find nexthop ifindex for address %pPAs",
+				__FILE__, __func__, &addr);
+		return false;
+	}
+
+	while (!found && (i < num_ifindex)) {
+		first_ifindex = nexthop_tab[i].ifindex;
+
+		ifp = if_lookup_by_index(first_ifindex, pim->vrf->vrf_id);
+		if (!ifp) {
+			if (PIM_DEBUG_ZEBRA)
+				zlog_debug(
+					"%s %s: could not find interface for ifindex %d (address %pPAs)",
+					__FILE__, __func__, first_ifindex,
+					&addr);
+			i++;
+			continue;
+		}
+
+		pim_ifp = ifp->info;
+		if (!pim_ifp || !pim_ifp->pim_enable) {
+			if (PIM_DEBUG_ZEBRA)
+				zlog_debug(
+					"%s: pim not enabled on input interface %s (ifindex=%d, RPF for source %pPAs)",
+					__func__, ifp->name, first_ifindex,
+					&addr);
+			i++;
+		} else if (neighbor_needed &&
+			   !pim_if_connected_to_source(ifp, addr)) {
+			nbr = pim_neighbor_find(
+				ifp, nexthop_tab[i].nexthop_addr, true);
+			if (PIM_DEBUG_PIM_TRACE_DETAIL)
+				zlog_debug("ifp name: %s, pim nbr: %p",
+					   ifp->name, nbr);
+			if (!nbr && !if_is_loopback(ifp))
+				i++;
+			else
+				found = 1;
+		} else
+			found = 1;
+	}
+
+	if (found) {
+		if (PIM_DEBUG_ZEBRA)
+			zlog_debug(
+				"%s %s: found nexthop %pPAs for address %pPAs: interface %s ifindex=%d metric=%d pref=%d",
+				__FILE__, __func__,
+				&nexthop_tab[i].nexthop_addr, &addr, ifp->name,
+				first_ifindex, nexthop_tab[i].route_metric,
+				nexthop_tab[i].protocol_distance);
+
+		/* update nexthop data */
+		nexthop->interface = ifp;
+		nexthop->mrib_nexthop_addr = nexthop_tab[i].nexthop_addr;
+		nexthop->mrib_metric_preference =
+			nexthop_tab[i].protocol_distance;
+		nexthop->mrib_route_metric = nexthop_tab[i].route_metric;
+		nexthop->last_lookup = addr;
+		nexthop->last_lookup_time = pim_time_monotonic_usec();
+		nexthop->nbr = nbr;
+		return true;
+	} else
+		return false;
+}
+
+static int nexthop_mismatch(const struct pim_nexthop *nh1,
+			    const struct pim_nexthop *nh2)
+{
+	return (nh1->interface != nh2->interface) ||
+	       (pim_addr_cmp(nh1->mrib_nexthop_addr, nh2->mrib_nexthop_addr)) ||
+	       (nh1->mrib_metric_preference != nh2->mrib_metric_preference) ||
+	       (nh1->mrib_route_metric != nh2->mrib_route_metric);
+}
+
+static void pim_rpf_cost_change(struct pim_instance *pim,
+		struct pim_upstream *up, uint32_t old_cost)
+{
+	struct pim_rpf *rpf = &up->rpf;
+	uint32_t new_cost;
+
+	new_cost = pim_up_mlag_local_cost(up);
+	if (PIM_DEBUG_MLAG)
+		zlog_debug(
+			"%s: Cost_to_rp of upstream-%s changed to:%u, from:%u",
+			__func__, up->sg_str, new_cost, old_cost);
+
+	if (old_cost == new_cost)
+		return;
+
+	/* Cost changed, it might Impact MLAG DF election, update */
+	if (PIM_DEBUG_MLAG)
+		zlog_debug(
+			"%s: Cost_to_rp of upstream-%s changed to:%u",
+			__func__, up->sg_str,
+			rpf->source_nexthop.mrib_route_metric);
+
+	if (pim_up_mlag_is_local(up))
+		pim_mlag_up_local_add(pim, up);
+}
+
+enum pim_rpf_result pim_rpf_update(struct pim_instance *pim,
+		struct pim_upstream *up, struct pim_rpf *old,
+		const char *caller)
+{
+	struct pim_rpf *rpf = &up->rpf;
+	struct pim_rpf saved;
+	pim_addr src;
+	struct prefix grp;
+	bool neigh_needed = true;
+	uint32_t saved_mrib_route_metric;
+
+	if (PIM_UPSTREAM_FLAG_TEST_STATIC_IIF(up->flags))
+		return PIM_RPF_OK;
+
+	if (pim_addr_is_any(up->upstream_addr)) {
+		zlog_debug("%s(%s): RP is not configured yet for %s",
+			__func__, caller, up->sg_str);
+		return PIM_RPF_OK;
+	}
+
+	saved.source_nexthop = rpf->source_nexthop;
+	saved.rpf_addr = rpf->rpf_addr;
+	saved_mrib_route_metric = pim_up_mlag_local_cost(up);
+	if (old) {
+		old->source_nexthop = saved.source_nexthop;
+		old->rpf_addr = saved.rpf_addr;
+	}
+
+	src = up->upstream_addr; // RP or Src address
+	pim_addr_to_prefix(&grp, up->sg.grp);
+
+	if ((pim_addr_is_any(up->sg.src) && I_am_RP(pim, up->sg.grp)) ||
+	    PIM_UPSTREAM_FLAG_TEST_FHR(up->flags))
+		neigh_needed = false;
+	pim_find_or_track_nexthop(pim, up->upstream_addr, up, NULL, NULL);
+	if (!pim_ecmp_nexthop_lookup(pim, &rpf->source_nexthop, src, &grp,
+				     neigh_needed)) {
+		/* Route is Deleted in Zebra, reset the stored NH data */
+		pim_upstream_rpf_clear(pim, up);
+		pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
+		return PIM_RPF_FAILURE;
+	}
+
+	rpf->rpf_addr = pim_rpf_find_rpf_addr(up);
+
+	if (pim_rpf_addr_is_inaddr_any(rpf) && PIM_DEBUG_ZEBRA) {
+		/* RPF'(S,G) not found */
+		zlog_debug("%s(%s): RPF'%s not found: won't send join upstream",
+			   __func__, caller, up->sg_str);
+		/* warning only */
+	}
+
+	/* detect change in pim_nexthop */
+	if (nexthop_mismatch(&rpf->source_nexthop, &saved.source_nexthop)) {
+
+		if (PIM_DEBUG_ZEBRA)
+			zlog_debug("%s(%s): (S,G)=%s source nexthop now is: interface=%s address=%pPAs pref=%d metric=%d",
+		 __func__, caller,
+		 up->sg_str,
+		 rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<ifname?>",
+		 &rpf->source_nexthop.mrib_nexthop_addr,
+		 rpf->source_nexthop.mrib_metric_preference,
+		 rpf->source_nexthop.mrib_route_metric);
+
+		pim_upstream_update_join_desired(pim, up);
+		pim_upstream_update_could_assert(up);
+		pim_upstream_update_my_assert_metric(up);
+	}
+
+	/* detect change in RPF_interface(S) */
+	if (saved.source_nexthop.interface != rpf->source_nexthop.interface) {
+
+		if (PIM_DEBUG_ZEBRA) {
+			zlog_debug("%s(%s): (S,G)=%s RPF_interface(S) changed from %s to %s",
+		 __func__, caller,
+		 up->sg_str,
+		 saved.source_nexthop.interface ? saved.source_nexthop.interface->name : "<oldif?>",
+		 rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<newif?>");
+			/* warning only */
+		}
+
+		pim_upstream_rpf_interface_changed(
+			up, saved.source_nexthop.interface);
+	}
+
+	/* detect change in RPF'(S,G) */
+	if (pim_addr_cmp(saved.rpf_addr, rpf->rpf_addr) ||
+	    saved.source_nexthop.interface != rpf->source_nexthop.interface) {
+		pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
+		return PIM_RPF_CHANGED;
+	}
+
+	if (PIM_DEBUG_MLAG)
+		zlog_debug(
+			"%s(%s): Cost_to_rp of upstream-%s changed to:%u",
+			__func__, caller, up->sg_str,
+			rpf->source_nexthop.mrib_route_metric);
+
+	pim_rpf_cost_change(pim, up, saved_mrib_route_metric);
+
+	return PIM_RPF_OK;
+}
+
+/*
+ * In the case of RP deletion and RP unreachablity,
+ * uninstall the mroute in the kernel and clear the
+ * rpf information in the pim upstream and pim channel
+ * oil data structure.
+ */
+void pim_upstream_rpf_clear(struct pim_instance *pim,
+			    struct pim_upstream *up)
+{
+	if (up->rpf.source_nexthop.interface) {
+		pim_upstream_switch(pim, up, PIM_UPSTREAM_NOTJOINED);
+		up->rpf.source_nexthop.interface = NULL;
+		up->rpf.source_nexthop.mrib_nexthop_addr = PIMADDR_ANY;
+		up->rpf.source_nexthop.mrib_metric_preference =
+			router->infinite_assert_metric.metric_preference;
+		up->rpf.source_nexthop.mrib_route_metric =
+			router->infinite_assert_metric.route_metric;
+		up->rpf.rpf_addr = PIMADDR_ANY;
+		pim_upstream_mroute_iif_update(up->channel_oil, __func__);
+	}
+}
+
+/*
+  RFC 4601: 4.1.6.  State Summarization Macros
+
+     neighbor RPF'(S,G) {
+	 if ( I_Am_Assert_Loser(S, G, RPF_interface(S) )) {
+	      return AssertWinner(S, G, RPF_interface(S) )
+	 } else {
+	      return NBR( RPF_interface(S), MRIB.next_hop( S ) )
+	 }
+     }
+
+  RPF'(*,G) and RPF'(S,G) indicate the neighbor from which data
+  packets should be coming and to which joins should be sent on the RP
+  tree and SPT, respectively.
+*/
+static pim_addr pim_rpf_find_rpf_addr(struct pim_upstream *up)
+{
+	struct pim_ifchannel *rpf_ch;
+	struct pim_neighbor *neigh;
+	pim_addr rpf_addr;
+
+	if (!up->rpf.source_nexthop.interface) {
+		zlog_warn("%s: missing RPF interface for upstream (S,G)=%s",
+			  __func__, up->sg_str);
+
+		return PIMADDR_ANY;
+	}
+
+	rpf_ch = pim_ifchannel_find(up->rpf.source_nexthop.interface, &up->sg);
+	if (rpf_ch) {
+		if (rpf_ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
+			return rpf_ch->ifassert_winner;
+		}
+	}
+
+	/* return NBR( RPF_interface(S), MRIB.next_hop( S ) ) */
+
+	neigh = pim_if_find_neighbor(up->rpf.source_nexthop.interface,
+				     up->rpf.source_nexthop.mrib_nexthop_addr);
+	if (neigh)
+		rpf_addr = neigh->source_addr;
+	else
+		rpf_addr = PIMADDR_ANY;
+
+	return rpf_addr;
+}
+
+int pim_rpf_addr_is_inaddr_any(struct pim_rpf *rpf)
+{
+	return pim_addr_is_any(rpf->rpf_addr);
+}
+
+int pim_rpf_is_same(struct pim_rpf *rpf1, struct pim_rpf *rpf2)
+{
+	if (rpf1->source_nexthop.interface == rpf2->source_nexthop.interface)
+		return 1;
+
+	return 0;
+}
+
+unsigned int pim_rpf_hash_key(const void *arg)
+{
+	const struct pim_nexthop_cache *r = arg;
+
+#if PIM_IPV == 4
+	return jhash_1word(r->rpf.rpf_addr.s_addr, 0);
+#else
+	return jhash2(r->rpf.rpf_addr.s6_addr32,
+		      array_size(r->rpf.rpf_addr.s6_addr32), 0);
+#endif
+}
+
+bool pim_rpf_equal(const void *arg1, const void *arg2)
+{
+	const struct pim_nexthop_cache *r1 =
+		(const struct pim_nexthop_cache *)arg1;
+	const struct pim_nexthop_cache *r2 =
+		(const struct pim_nexthop_cache *)arg2;
+
+	return (!pim_addr_cmp(r1->rpf.rpf_addr, r2->rpf.rpf_addr));
+}