pimd: Only create and bind the autorp socket when really needed

Previously, the autorp socket would get created and bind if needed
by autorp configuration.
This update limits it further to also require pim enabled interfaces
in the vrf before the socket is created and bind.
So now the socket will automatically close if there are no pim
enabled interfaces left, or if autorp is turned off. It will
automatically turn on if autorp is turned on and there are pim
enabled interfaces in the vrf.

Signed-off-by: Nathan Bahr <nbahr@atcorp.com>

pimd/pim_autorp.c

@@ -113,10 +113,33 @@ static void pim_autorp_free(struct pim_autorp *autorp)
 		XFREE(MTYPE_PIM_AUTORP_ANNOUNCE, autorp->announce_pkt);
 }
 
+static bool autorp_is_pim_interface(struct interface *ifp)
+{
+	struct pim_interface *pim_ifp = ifp->info;
+
+	return CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_ACTIVE) && pim_ifp && pim_ifp->pim_enable &&
+	       !pim_ifp->pim_passive_enable;
+}
+
+static bool pim_autorp_should_enable_socket(struct pim_autorp *autorp)
+{
+	struct interface *ifp;
+
+	/* Only enable the socket if there are any PIM enabled interfaces */
+	FOR_ALL_INTERFACES (autorp->pim->vrf, ifp) {
+		if (autorp_is_pim_interface(ifp))
+			return true;
+	}
+	return false;
+}
+
 static bool pim_autorp_should_close(struct pim_autorp *autorp)
 {
-	/* If discovery or mapping agent is active, then we need the socket open */
+	/* If discovery or mapping agent is active, then we need the socket open. We also want to leave
-	return !autorp->do_discovery && !autorp->send_rp_discovery;
+	 * the socket open if there are any pim interfaces and we have an announcement packet to send.
+	 */
+	return !autorp->do_discovery && !autorp->send_rp_discovery &&
+	       !(pim_autorp_should_enable_socket(autorp) && autorp->announce_timer != NULL);
 }
 
 static bool pim_autorp_join_groups(struct interface *ifp)
@@ -684,8 +707,14 @@ static void autorp_send_discovery_on(struct pim_autorp *autorp)
 	int interval = 5;
 
 	/* Make sure the socket is open and ready */
-	if (!pim_autorp_socket_enable(autorp)) {
+	if (pim_autorp_should_enable_socket(autorp)) {
-		zlog_err("%s: AutoRP failed to open socket", __func__);
+		if (!pim_autorp_socket_enable(autorp)) {
+			zlog_err("%s: AutoRP failed to open socket", __func__);
+			return;
+		}
+	} else {
+		if (PIM_DEBUG_AUTORP)
+			zlog_debug("%s: No PIM interfaces, not enabling socket", __func__);
 		return;
 	}
 
@@ -964,6 +993,7 @@ err:
 	return;
 }
 
+static void pim_autorp_new_announcement(struct pim_instance *pim);
 static bool pim_autorp_socket_enable(struct pim_autorp *autorp)
 {
 	int fd;
@@ -1006,9 +1036,19 @@ static bool pim_autorp_socket_enable(struct pim_autorp *autorp)
 	if (PIM_DEBUG_AUTORP)
 		zlog_debug("%s: AutoRP socket enabled (fd=%u)", __func__, fd);
 
+	if (autorp->do_discovery)
+		autorp_read_on(autorp);
+
+	if (autorp->send_rp_discovery)
+		autorp_send_discovery_on(autorp);
+
+	/* Try to build a new announcement to make sure the send timer is enabled */
+	pim_autorp_new_announcement(autorp->pim);
+
 	return true;
 }
 
+static void autorp_announcement_off(struct pim_autorp *autorp);
 static bool pim_autorp_socket_disable(struct pim_autorp *autorp)
 {
 	/* Return early if socket is already disabled */
@@ -1022,6 +1062,8 @@ static bool pim_autorp_socket_disable(struct pim_autorp *autorp)
 		return false;
 	}
 
+	autorp_send_discovery_off(autorp);
+	autorp_announcement_off(autorp);
 	autorp_read_off(autorp);
 	autorp->sock = -1;
 
@@ -1058,8 +1100,7 @@ static void autorp_send_announcement(struct event *evt)
 			/* Only send on active interfaces with full pim enabled, non-passive
 			 * and have a primary address set.
 			 */
-			if (CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_ACTIVE) && pim_ifp &&
+			if (autorp_is_pim_interface(ifp) &&
-			    pim_ifp->pim_enable && !pim_ifp->pim_passive_enable &&
 			    !pim_addr_is_any(pim_ifp->primary_address)) {
 				if (setsockopt(autorp->sock, IPPROTO_IP, IP_MULTICAST_IF,
 					       &(pim_ifp->primary_address),
@@ -1108,6 +1149,10 @@ static void autorp_announcement_off(struct pim_autorp *autorp)
 		if (PIM_DEBUG_AUTORP)
 			zlog_debug("%s: AutoRP announcement sending disabled", __func__);
 	event_cancel(&(autorp->announce_timer));
+
+	/* Close the socket if we need to */
+	if (pim_autorp_should_close(autorp) && !pim_autorp_socket_disable(autorp))
+		zlog_warn("%s: AutoRP failed to close socket", __func__);
 }
 
 /* Pack the groups of the RP
@@ -1279,8 +1324,20 @@ static void pim_autorp_new_announcement(struct pim_instance *pim)
 	autorp->announce_pkt_sz += sizeof(struct autorp_pkt_hdr);
 
 	/* Only turn on the announcement timer if we have a packet to send */
-	if (autorp->announce_pkt_sz >= MIN_AUTORP_PKT_SZ)
+	if (autorp->announce_pkt_sz >= MIN_AUTORP_PKT_SZ) {
+		/* We are sending an announcement, but discovery could be off, so make sure the socket is open */
+		if (pim_autorp_should_enable_socket(autorp)) {
+			if (!pim_autorp_socket_enable(autorp)) {
+				zlog_err("%s: AutoRP failed to open socket", __func__);
+				return;
+			}
+		} else {
+			if (PIM_DEBUG_AUTORP)
+				zlog_debug("%s: No PIM interfaces, not enabling socket", __func__);
+			return;
+		}
 		autorp_announcement_on(autorp);
+	}
 }
 
 void pim_autorp_prefix_list_update(struct pim_instance *pim, struct prefix_list *plist)
@@ -1453,10 +1510,15 @@ void pim_autorp_add_ifp(struct interface *ifp)
 	struct pim_interface *pim_ifp;
 
 	pim_ifp = ifp->info;
-	if (CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_ACTIVE) && pim_ifp && pim_ifp->pim_enable) {
+	if (autorp_is_pim_interface(ifp)) {
 		pim = pim_ifp->pim;
-		if (pim && pim->autorp &&
+		if (pim && pim->autorp && !pim_autorp_should_close(pim->autorp)) {
-		    (pim->autorp->do_discovery || pim->autorp->send_rp_discovery)) {
+			/* Make sure the socket is open and ready */
+			if (!pim_autorp_socket_enable(pim->autorp)) {
+				zlog_err("%s: AutoRP failed to open socket", __func__);
+				return;
+			}
+
 			if (PIM_DEBUG_AUTORP)
 				zlog_debug("%s: Adding interface %s to AutoRP, joining AutoRP groups",
 					   __func__, ifp->name);
@@ -1475,11 +1537,13 @@ void pim_autorp_rm_ifp(struct interface *ifp)
 	 */
 	struct pim_instance *pim;
 	struct pim_interface *pim_ifp;
+	struct pim_autorp *autorp = NULL;
 
 	pim_ifp = ifp->info;
 	if (CHECK_FLAG(ifp->status, ZEBRA_INTERFACE_ACTIVE) && pim_ifp) {
 		pim = pim_ifp->pim;
 		if (pim && pim->autorp) {
+			autorp = pim->autorp;
 			if (PIM_DEBUG_AUTORP)
 				zlog_debug("%s: Removing interface %s from AutoRP, leaving AutoRP groups",
 					   __func__, ifp->name);
@@ -1488,6 +1552,11 @@ void pim_autorp_rm_ifp(struct interface *ifp)
 					  safe_strerror(errno));
 		}
 	}
+
+	if (autorp != NULL && !pim_autorp_should_enable_socket(autorp)) {
+		/* Removed the last pim enabled interface, close the socket */
+		pim_autorp_socket_disable(autorp);
+	}
 }
 
 void pim_autorp_start_discovery(struct pim_instance *pim)
@@ -1500,8 +1569,14 @@ void pim_autorp_start_discovery(struct pim_instance *pim)
 	autorp->do_discovery = true;
 
 	/* Make sure the socket is open and ready */
-	if (!pim_autorp_socket_enable(autorp)) {
+	if (pim_autorp_should_enable_socket(autorp)) {
-		zlog_err("%s: AutoRP failed to open socket", __func__);
+		if (!pim_autorp_socket_enable(autorp)) {
+			zlog_err("%s: AutoRP failed to open socket", __func__);
+			return;
+		}
+	} else {
+		if (PIM_DEBUG_AUTORP)
+			zlog_debug("%s: No PIM interfaces, not enabling socket", __func__);
 		return;
 	}
 

pimd/pim_iface.c

@@ -2017,12 +2017,12 @@ void pim_pim_interface_delete(struct interface *ifp)
 	if (!pim_ifp)
 		return;
 
+	pim_ifp->pim_enable = false;
+
 #if PIM_IPV == 4
 	pim_autorp_rm_ifp(ifp);
 #endif
 
-	pim_ifp->pim_enable = false;
-
 	pim_if_membership_clear(ifp);
 
 	/*

pimd/pim_nb_config.c

@@ -3285,7 +3285,6 @@ int routing_control_plane_protocols_control_plane_protocol_pim_address_family_rp
 {
 	struct vrf *vrf;
 	struct pim_instance *pim;
-	bool enabled;
 
 	switch (args->event) {
 	case NB_EV_VALIDATE:
@@ -3295,10 +3294,8 @@ int routing_control_plane_protocols_control_plane_protocol_pim_address_family_rp
 	case NB_EV_APPLY:
 		vrf = nb_running_get_entry(args->dnode, NULL, true);
 		pim = vrf->info;
-		enabled = yang_dnode_get_bool(args->dnode, NULL);
 		/* Run AutoRP discovery by default */
-		if (!enabled)
+		pim_autorp_start_discovery(pim);
-			pim_autorp_start_discovery(pim);
 		break;
 	}