pimd,yang: Reimplement RPF lookup vty in router pim

Add rpf-lookup-mode MODE vty command under router pim block.
Including NB piping and config write. Using the mode still pending.

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

8 files changed, 130 insertions, 5 deletions

diff --git a/pimd/pim_cmd.c b/pimd/pim_cmd.c
index 3fabe1706c..1d89ec100a 100644
--- a/pimd/pim_cmd.c
+++ b/pimd/pim_cmd.c
@@ -8851,6 +8851,24 @@ done:
 	return ret;
 }
 
+DEFPY_YANG(pim_rpf_lookup_mode, pim_rpf_lookup_mode_cmd,
+           "[no] rpf-lookup-mode ![urib-only|mrib-only|mrib-then-urib|lower-distance|longer-prefix]$mode",
+           NO_STR
+           "RPF lookup behavior\n"
+           "Lookup in unicast RIB only\n"
+           "Lookup in multicast RIB only\n"
+           "Try multicast RIB first, fall back to unicast RIB\n"
+           "Lookup both, use entry with lower distance\n"
+           "Lookup both, use entry with longer prefix\n")
+{
+	if (no)
+		nb_cli_enqueue_change(vty, "./mcast-rpf-lookup", NB_OP_DESTROY, NULL);
+	else
+		nb_cli_enqueue_change(vty, "./mcast-rpf-lookup", NB_OP_MODIFY, mode);
+
+	return nb_cli_apply_changes(vty, NULL);
+}
+
 struct cmd_node pim_node = {
 	.name = "pim",
 	.node = PIM_NODE,
@@ -9017,6 +9035,8 @@ void pim_cmd_init(void)
 	install_element(PIM_NODE, &pim_bsr_candidate_rp_group_cmd);
 	install_element(PIM_NODE, &pim_bsr_candidate_bsr_cmd);
 
+	install_element(PIM_NODE, &pim_rpf_lookup_mode_cmd);
+
 	install_element(INTERFACE_NODE, &interface_ip_igmp_cmd);
 	install_element(INTERFACE_NODE, &interface_no_ip_igmp_cmd);
 	install_element(INTERFACE_NODE, &interface_ip_igmp_join_cmd);
diff --git a/pimd/pim_instance.h b/pimd/pim_instance.h
index 93acb5e9fd..d491cd63c6 100644
--- a/pimd/pim_instance.h
+++ b/pimd/pim_instance.h
@@ -116,6 +116,7 @@ struct pim_instance {
 	char *register_plist;
 
 	struct hash *rpf_hash;
+	enum pim_rpf_lookup_mode rpf_mode;
 
 	void *ssm_info; /* per-vrf SSM configuration */
 
diff --git a/pimd/pim_nb.c b/pimd/pim_nb.c
index b5d20419dd..7bb529d44c 100644
--- a/pimd/pim_nb.c
+++ b/pimd/pim_nb.c
@@ -257,6 +257,12 @@ const struct frr_yang_module_info frr_pim_info = {
 			}
 		},
 		{
+			.xpath = "/frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-pim:pim/address-family/mcast-rpf-lookup",
+			.cbs = {
+				.modify = routing_control_plane_protocols_control_plane_protocol_pim_address_family_mcast_rpf_lookup_modify,
+			}
+		},
+		{
 			.xpath = "/frr-interface:lib/interface/frr-pim:pim/address-family",
 			.cbs = {
 				.create = lib_interface_pim_address_family_create,
diff --git a/pimd/pim_nb.h b/pimd/pim_nb.h
index 7d30db04be..15ae74e711 100644
--- a/pimd/pim_nb.h
+++ b/pimd/pim_nb.h
@@ -100,6 +100,8 @@ int routing_control_plane_protocols_control_plane_protocol_pim_address_family_re
 	struct nb_cb_modify_args *args);
 int routing_control_plane_protocols_control_plane_protocol_pim_address_family_register_accept_list_destroy(
 	struct nb_cb_destroy_args *args);
+int routing_control_plane_protocols_control_plane_protocol_pim_address_family_mcast_rpf_lookup_modify(
+	struct nb_cb_modify_args *args);
 int lib_interface_pim_address_family_dr_priority_modify(
 	struct nb_cb_modify_args *args);
 int lib_interface_pim_address_family_create(struct nb_cb_create_args *args);
diff --git a/pimd/pim_nb_config.c b/pimd/pim_nb_config.c
index fb7047aa49..905bc5a137 100644
--- a/pimd/pim_nb_config.c
+++ b/pimd/pim_nb_config.c
@@ -1847,6 +1847,34 @@ int routing_control_plane_protocols_control_plane_protocol_pim_address_family_re
 }
 
 /*
+ * XPath: /frr-routing:routing/control-plane-protocols/control-plane-protocol/frr-pim:pim/address-family/mcast-rpf-lookup
+ */
+int routing_control_plane_protocols_control_plane_protocol_pim_address_family_mcast_rpf_lookup_modify(
+	struct nb_cb_modify_args *args)
+{
+	struct vrf *vrf;
+	struct pim_instance *pim;
+	enum pim_rpf_lookup_mode old_mode;
+
+	switch (args->event) {
+	case NB_EV_VALIDATE:
+	case NB_EV_PREPARE:
+	case NB_EV_ABORT:
+		break;
+	case NB_EV_APPLY:
+		vrf = nb_running_get_entry(args->dnode, NULL, true);
+		pim = vrf->info;
+		old_mode = pim->rpf_mode;
+		pim->rpf_mode = yang_dnode_get_enum(args->dnode, NULL);
+
+		/* TODO: Signal to redo lookups? */
+		break;
+	}
+
+	return NB_OK;
+}
+
+/*
  * XPath: /frr-interface:lib/interface/frr-pim:pim/address-family
  */
 int lib_interface_pim_address_family_create(struct nb_cb_create_args *args)
@@ -2666,9 +2694,8 @@ int lib_interface_pim_address_family_mroute_oif_modify(
 
 #ifdef PIM_ENFORCE_LOOPFREE_MFC
 		iif = nb_running_get_entry(args->dnode, NULL, false);
-		if (!iif) {
+		if (!iif)
 			return NB_OK;
-		}
 
 		pim_iifp = iif->info;
 		pim = pim_iifp->pim;
diff --git a/pimd/pim_rpf.h b/pimd/pim_rpf.h
index 7dae53f8fc..6ff4d87b55 100644
--- a/pimd/pim_rpf.h
+++ b/pimd/pim_rpf.h
@@ -41,6 +41,17 @@ struct pim_rpf {
 
 enum pim_rpf_result { PIM_RPF_OK = 0, PIM_RPF_CHANGED, PIM_RPF_FAILURE };
 
+/* RPF lookup behaviour */
+enum pim_rpf_lookup_mode {
+	MCAST_NO_CONFIG = 0,  /* MIX_MRIB_FIRST, but no show in config write */
+	MCAST_MRIB_ONLY,      /* MRIB only */
+	MCAST_URIB_ONLY,      /* URIB only */
+	MCAST_MIX_MRIB_FIRST, /* MRIB, if nothing at all then URIB */
+	MCAST_MIX_DISTANCE,   /* MRIB & URIB, lower distance wins */
+	MCAST_MIX_PFXLEN,     /* MRIB & URIB, longer prefix wins */
+			      /* on equal value, MRIB wins for last 2 */
+};
+
 struct pim_upstream;
 
 unsigned int pim_rpf_hash_key(const void *arg);
diff --git a/pimd/pim_vty.c b/pimd/pim_vty.c
index fc9781b239..974cf30cf1 100644
--- a/pimd/pim_vty.c
+++ b/pimd/pim_vty.c
@@ -275,6 +275,16 @@ int pim_global_config_write_worker(struct pim_instance *pim, struct vty *vty)
 		}
 	}
 
+	if (pim->rpf_mode != MCAST_NO_CONFIG) {
+		++writes;
+		vty_out(vty, " rpf-lookup-mode %s\n",
+			pim->rpf_mode == MCAST_URIB_ONLY	? "urib-only"
+			: pim->rpf_mode == MCAST_MRIB_ONLY	? "mrib-only"
+			: pim->rpf_mode == MCAST_MIX_MRIB_FIRST ? "mrib-then-urib"
+			: pim->rpf_mode == MCAST_MIX_DISTANCE	? "lower-distance"
+								: "longer-prefix");
+	}
+
 	return writes;
 }
 
diff --git a/yang/frr-pim.yang b/yang/frr-pim.yang
index 6e5fc3c6ce..e371894474 100644
--- a/yang/frr-pim.yang
+++ b/yang/frr-pim.yang
@@ -83,6 +83,47 @@ module frr-pim {
   }
 
   /*
+   * Multicast RPF mode configurable type
+   */
+
+  typedef mcast-rpf-lookup-mode {
+    type enumeration {
+      enum "none" {
+        value 0;
+        description
+          "No mode set.";
+      }
+      enum "mrib-only" {
+        value 1;
+        description
+          "Lookup in unicast RIB only.";
+      }
+      enum "urib-only" {
+        value 2;
+        description
+          "Lookup in multicast RIB only.";
+      }
+      enum "mrib-then-urib" {
+        value 3;
+        description
+          "Try multicast RIB first, fall back to unicast RIB.";
+      }
+      enum "lower-distance" {
+        value 4;
+        description
+          "Lookup both unicast and mcast, use entry with lower distance.";
+      }
+      enum "longer-prefix" {
+        value 5;
+        description
+          "Lookup both unicast and mcast, use entry with longer prefix.";
+      }
+    }
+    description
+      "Multicast RPF lookup behavior";
+  }
+
+  /*
    * Groupings
    */
 
@@ -161,20 +202,27 @@ module frr-pim {
     description
       "A grouping defining per address family pim global attributes";
 
+    leaf mcast-rpf-lookup {
+      type mcast-rpf-lookup-mode;
+      default "none";
+      description
+        "Multicast RPF lookup behavior.";
+    }
+
     leaf ecmp {
       type boolean;
       default "false";
       description
         "Enable PIM ECMP.";
     }
-    
+
     leaf ecmp-rebalance {
       type boolean;
       default "false";
       description
         "Enable PIM ECMP Rebalance.";
     }
-    
+
     leaf keep-alive-timer {
       type uint16 {
         range "1..max";
@@ -183,7 +231,7 @@ module frr-pim {
       description
         "Keep alive Timer in seconds.";
     }
-    
+
     leaf rp-keep-alive-timer {
       type uint16 {
         range "1..max";