bgpd: handle bgp pbr hash list destroy upon BGP destroy

Upon BGP destroy, the hash list related to PBR are removed.
The pbr_match entries, as well as the contained pbr_match_entries
entries.
Then the pbr_action entries. The order is important, since the former
are referencing pbr_action. So the references must be removed, prior to
remove pbr action.
Also, the zebra associated contexts are removed.

Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>

bgpd/bgp_pbr.c

@@ -309,6 +309,48 @@ static int bgp_pbr_build_and_validate_entry(struct prefix *p,
 	return 0;
 }
 
+static void bgp_pbr_match_entry_free(void *arg)
+{
+	struct bgp_pbr_match_entry *bpme;
+
+	bpme = (struct bgp_pbr_match_entry *)arg;
+
+	if (bpme->installed) {
+		bgp_send_pbr_ipset_entry_match(bpme, false);
+		bpme->installed = false;
+		bpme->backpointer = NULL;
+	}
+	XFREE(MTYPE_PBR_MATCH_ENTRY, bpme);
+}
+
+static void bgp_pbr_match_free(void *arg)
+{
+	struct bgp_pbr_match *bpm;
+
+	bpm = (struct bgp_pbr_match *)arg;
+
+	hash_clean(bpm->entry_hash, bgp_pbr_match_entry_free);
+
+	if (hashcount(bpm->entry_hash) == 0) {
+		/* delete iptable entry first */
+		/* then delete ipset match */
+		if (bpm->installed) {
+			if (bpm->installed_in_iptable) {
+				bgp_send_pbr_iptable(bpm->action,
+						     bpm, false);
+				bpm->installed_in_iptable = false;
+				bpm->action->refcnt--;
+			}
+			bgp_send_pbr_ipset_match(bpm, false);
+			bpm->installed = false;
+			bpm->action = NULL;
+		}
+	}
+	hash_free(bpm->entry_hash);
+
+	XFREE(MTYPE_PBR_MATCH, bpm);
+}
+
 static void *bgp_pbr_match_alloc_intern(void *arg)
 {
 	struct bgp_pbr_match *bpm, *new;
@@ -321,6 +363,24 @@ static void *bgp_pbr_match_alloc_intern(void *arg)
 	return new;
 }
 
+static void bgp_pbr_action_free(void *arg)
+{
+	struct bgp_pbr_action *bpa;
+
+	bpa = (struct bgp_pbr_action *)arg;
+
+	if (bpa->refcnt == 0) {
+		if (bpa->installed && bpa->table_id != 0) {
+			bgp_send_pbr_rule_action(bpa, false);
+			bgp_zebra_announce_default(bpa->bgp, &(bpa->nh),
+						   AFI_IP,
+						   bpa->table_id,
+						   false);
+		}
+	}
+	XFREE(MTYPE_PBR_ACTION, bpa);
+}
+
 static void *bgp_pbr_action_alloc_intern(void *arg)
 {
 	struct bgp_pbr_action *bpa, *new;
@@ -515,6 +575,20 @@ struct bgp_pbr_match *bgp_pbr_match_iptable_lookup(vrf_id_t vrf_id,
 	return bpmiu.bpm_found;
 }
 
+void bgp_pbr_cleanup(struct bgp *bgp)
+{
+	if (bgp->pbr_match_hash) {
+		hash_clean(bgp->pbr_match_hash, bgp_pbr_match_free);
+		hash_free(bgp->pbr_match_hash);
+		bgp->pbr_match_hash = NULL;
+	}
+	if (bgp->pbr_action_hash) {
+		hash_clean(bgp->pbr_action_hash, bgp_pbr_action_free);
+		hash_free(bgp->pbr_action_hash);
+		bgp->pbr_action_hash = NULL;
+	}
+}
+
 void bgp_pbr_init(struct bgp *bgp)
 {
 	bgp->pbr_match_hash =
@@ -685,6 +759,7 @@ static void bgp_pbr_flush_entry(struct bgp *bgp, struct bgp_pbr_action *bpa,
 				bgp_send_pbr_iptable(bpm->action,
 						     bpm, false);
 				bpm->installed_in_iptable = false;
+				bpm->action->refcnt--;
 			}
 			bgp_send_pbr_ipset_match(bpm, false);
 			bpm->installed = false;
@@ -695,6 +770,15 @@ static void bgp_pbr_flush_entry(struct bgp *bgp, struct bgp_pbr_action *bpa,
 		 * note that drop does not need to call send_pbr_action
 		 */
 	}
+	if (bpa->refcnt == 0) {
+		if (bpa->installed && bpa->table_id != 0) {
+			bgp_send_pbr_rule_action(bpa, false);
+			bgp_zebra_announce_default(bpa->bgp, &(bpa->nh),
+						   AFI_IP,
+						   bpa->table_id,
+						   false);
+		}
+	}
 }
 
 struct bgp_pbr_match_entry_remain {
@@ -821,6 +905,7 @@ static void bgp_pbr_policyroute_add_to_zebra(struct bgp *bgp,
 			bpa->table_id = bpa->fwmark;
 			bpa->installed = false;
 		}
+		bpa->bgp = bgp;
 		bpa->unique = ++bgp_pbr_action_counter_unique;
 		/* 0 value is forbidden */
 		bpa->install_in_progress = false;

bgpd/bgp_pbr.h

@@ -215,7 +215,8 @@ struct bgp_pbr_action {
 
 	bool installed;
 	bool install_in_progress;
-
+	uint32_t refcnt;
+	struct bgp *bgp;
 };
 
 extern struct bgp_pbr_action *bgp_pbr_action_rule_lookup(vrf_id_t vrf_id,
@@ -230,6 +231,7 @@ extern struct bgp_pbr_match_entry *bgp_pbr_match_ipset_entry_lookup(
 extern struct bgp_pbr_match *bgp_pbr_match_iptable_lookup(vrf_id_t vrf_id,
 							  uint32_t unique);
 
+extern void bgp_pbr_cleanup(struct bgp *bgp);
 extern void bgp_pbr_init(struct bgp *bgp);
 
 extern uint32_t bgp_pbr_action_hash_key(void *arg);

bgpd/bgp_zebra.c

@@ -2112,6 +2112,7 @@ static int iptable_notify_owner(int command, struct zclient *zclient,
 		if (BGP_DEBUG(zebra, ZEBRA))
 			zlog_debug("%s: Received IPTABLE_INSTALLED",
 				   __PRETTY_FUNCTION__);
+		bgpm->action->refcnt++;
 		break;
 	case ZAPI_IPTABLE_REMOVED:
 		if (BGP_DEBUG(zebra, ZEBRA))
@@ -2580,8 +2581,10 @@ void bgp_send_pbr_iptable(struct bgp_pbr_action *pba,
 	bgp_encode_pbr_iptable_match(s, pba, pbm);
 
 	stream_putw_at(s, 0, stream_get_endp(s));
-	if (!zclient_send_message(zclient) && install)
+	if (!zclient_send_message(zclient) && install) {
 		pbm->install_iptable_in_progress = true;
+		pba->refcnt++;
+	}
 }
 
 /* inject in table <table_id> a default route to:

bgpd/bgpd.c

@@ -3403,7 +3403,7 @@ void bgp_free(struct bgp *bgp)
 	bf_release_index(bm->rd_idspace, bgp->vrf_rd_id);
 
 	bgp_evpn_cleanup(bgp);
-
+	bgp_pbr_cleanup(bgp);
 	if (bgp->name)
 		XFREE(MTYPE_BGP, bgp->name);
 	if (bgp->name_pretty)