isisd: add MT configuration

Signed-off-by: Christian Franke <chris@opensourcerouting.org>

8 files changed, 525 insertions, 2 deletions

diff --git a/isisd/Makefile.am b/isisd/Makefile.am
index c97385f87..2973820ee 100644
--- a/isisd/Makefile.am
+++ b/isisd/Makefile.am
@@ -16,7 +16,7 @@ libisis_a_SOURCES = \
 	isis_tlv.c isisd.c isis_misc.c isis_zebra.c isis_dr.c \
 	isis_flags.c isis_dynhn.c iso_checksum.c isis_csm.c isis_events.c \
 	isis_spf.c isis_redist.c isis_route.c isis_routemap.c isis_te.c \
-	isis_vty.c
+	isis_vty.c isis_mt.c
 
 
 noinst_HEADERS = \
@@ -25,7 +25,7 @@ noinst_HEADERS = \
 	isis_lsp.h dict.h isis_circuit.h isis_misc.h isis_network.h \
 	isis_zebra.h isis_dr.h isis_flags.h isis_dynhn.h isis_common.h \
 	iso_checksum.h isis_csm.h isis_events.h isis_spf.h isis_redist.h \
-	isis_route.h isis_routemap.h isis_te.h
+	isis_route.h isis_routemap.h isis_te.h isis_mt.h
 
 isisd_SOURCES = \
 	isis_main.c $(libisis_a_SOURCES) \
diff --git a/isisd/isis_circuit.c b/isisd/isis_circuit.c
index 6207ae189..6caf8200e 100644
--- a/isisd/isis_circuit.c
+++ b/isisd/isis_circuit.c
@@ -60,6 +60,7 @@
 #include "isisd/isis_csm.h"
 #include "isisd/isis_events.h"
 #include "isisd/isis_te.h"
+#include "isisd/isis_mt.h"
 
 DEFINE_QOBJ_TYPE(isis_circuit)
 
@@ -102,6 +103,8 @@ isis_circuit_new ()
 
   circuit->mtc = mpls_te_circuit_new();
 
+  circuit_mt_init(circuit);
+
   QOBJ_REG (circuit, isis_circuit);
 
   return circuit;
@@ -117,6 +120,8 @@ isis_circuit_del (struct isis_circuit *circuit)
 
   isis_circuit_if_unbind (circuit, circuit->interface);
 
+  circuit_mt_finish(circuit);
+
   /* and lastly the circuit itself */
   XFREE (MTYPE_ISIS_CIRCUIT, circuit);
 
@@ -1215,6 +1220,7 @@ isis_interface_config_write (struct vty *vty)
                        VTY_NEWLINE);
               write++;
             }
+          write += circuit_write_mt_settings(circuit, vty);
         }
       vty_out (vty, "!%s", VTY_NEWLINE);
     }
@@ -1383,6 +1389,22 @@ isis_circuit_circ_type_set(struct isis_circuit *circuit, int circ_type)
 }
 
 int
+isis_circuit_mt_enabled_set (struct isis_circuit *circuit, uint16_t mtid,
+                             bool enabled)
+{
+  struct isis_circuit_mt_setting *setting;
+
+  setting = circuit_get_mt_setting(circuit, mtid);
+  if (setting->enabled != enabled)
+    {
+      setting->enabled = enabled;
+      lsp_regenerate_schedule (circuit->area, IS_LEVEL_1 | IS_LEVEL_2, 0);
+    }
+
+  return CMD_SUCCESS;
+}
+
+int
 isis_if_new_hook (struct interface *ifp)
 {
   return 0;
diff --git a/isisd/isis_circuit.h b/isisd/isis_circuit.h
index bb0dc0f98..16dfa6304 100644
--- a/isisd/isis_circuit.h
+++ b/isisd/isis_circuit.h
@@ -123,6 +123,7 @@ struct isis_circuit
   struct mpls_te_circuit *mtc; /* Support for MPLS-TE parameters - see isis_te.[c,h] */
   int ip_router;		/* Route IP ? */
   int is_passive;		/* Is Passive ? */
+  struct list *mt_settings;	/* IS-IS MT Settings */
   struct list *ip_addrs;	/* our IP addresses */
   int ipv6_router;		/* Route IPv6 ? */
   struct list *ipv6_link;	/* our link local IPv6 addresses */
@@ -187,4 +188,6 @@ int  isis_circuit_passwd_unset (struct isis_circuit *circuit);
 int  isis_circuit_passwd_cleartext_set (struct isis_circuit *circuit, const char *passwd);
 int  isis_circuit_passwd_hmac_md5_set (struct isis_circuit *circuit, const char *passwd);
 
+int isis_circuit_mt_enabled_set (struct isis_circuit *circuit, uint16_t mtid, bool enabled);
+
 #endif /* _ZEBRA_ISIS_CIRCUIT_H */
diff --git a/isisd/isis_mt.c b/isisd/isis_mt.c
new file mode 100644
index 000000000..7908fd4bb
--- /dev/null
+++ b/isisd/isis_mt.c
@@ -0,0 +1,262 @@
+/*
+ * IS-IS Rout(e)ing protocol - Multi Topology Support
+ *
+ * Copyright (C) 2017 Christian Franke
+ *
+ * This file is part of FreeRangeRouting (FRR)
+ *
+ * FRR 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, or (at your option) any
+ * later version.
+ *
+ * FRR 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 FRR; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+#include <zebra.h>
+#include "isisd/isisd.h"
+#include "isisd/isis_memory.h"
+#include "isisd/isis_circuit.h"
+#include "isisd/isis_mt.h"
+
+DEFINE_MTYPE_STATIC(ISISD, MT_AREA_SETTING, "ISIS MT Area Setting")
+DEFINE_MTYPE_STATIC(ISISD, MT_CIRCUIT_SETTING, "ISIS MT Circuit Setting")
+
+/* MT naming api */
+const char *isis_mtid2str(uint16_t mtid)
+{
+  switch(mtid)
+    {
+      case ISIS_MT_IPV4_UNICAST:
+        return "ipv4-unicast";
+      case ISIS_MT_IPV4_MGMT:
+        return "ipv4-mgmt";
+      case ISIS_MT_IPV6_UNICAST:
+        return "ipv6-unicast";
+      case ISIS_MT_IPV4_MULTICAST:
+        return "ipv4-multicast";
+      case ISIS_MT_IPV6_MULTICAST:
+        return "ipv6-multicast";
+      case ISIS_MT_IPV6_MGMT:
+        return "ipv6-mgmt";
+      default:
+        return NULL;
+    }
+}
+
+uint16_t isis_str2mtid(const char *name)
+{
+  if (!strcmp(name,"ipv4-unicast"))
+    return ISIS_MT_IPV4_UNICAST;
+  if (!strcmp(name,"ipv4-mgmt"))
+    return ISIS_MT_IPV4_MGMT;
+  if (!strcmp(name,"ipv6-unicast"))
+    return ISIS_MT_IPV6_UNICAST;
+  if (!strcmp(name,"ipv4-multicast"))
+    return ISIS_MT_IPV4_MULTICAST;
+  if (!strcmp(name,"ipv6-multicast"))
+    return ISIS_MT_IPV6_MULTICAST;
+  if (!strcmp(name,"ipv6-mgmt"))
+    return ISIS_MT_IPV6_MGMT;
+  return -1;
+}
+
+/* General MT settings api */
+
+struct mt_setting {
+	ISIS_MT_INFO_FIELDS;
+};
+
+static void *
+lookup_mt_setting(struct list *mt_list, uint16_t mtid)
+{
+  struct listnode *node;
+  struct mt_setting *setting;
+
+  for (ALL_LIST_ELEMENTS_RO(mt_list, node, setting))
+    {
+      if (setting->mtid == mtid)
+        return setting;
+    }
+  return NULL;
+}
+
+static void
+add_mt_setting(struct list **mt_list, void *setting)
+{
+  if (!*mt_list)
+    *mt_list = list_new();
+  listnode_add(*mt_list, setting);
+}
+
+/* Area specific MT settings api */
+
+struct isis_area_mt_setting*
+area_lookup_mt_setting(struct isis_area *area, uint16_t mtid)
+{
+  return lookup_mt_setting(area->mt_settings, mtid);
+}
+
+struct isis_area_mt_setting*
+area_new_mt_setting(struct isis_area *area, uint16_t mtid)
+{
+  struct isis_area_mt_setting *setting;
+
+  setting = XCALLOC(MTYPE_MT_AREA_SETTING, sizeof(*setting));
+  setting->mtid = mtid;
+  return setting;
+}
+
+static void
+area_free_mt_setting(void *setting)
+{
+  XFREE(MTYPE_MT_AREA_SETTING, setting);
+}
+
+void
+area_add_mt_setting(struct isis_area *area, struct isis_area_mt_setting *setting)
+{
+  add_mt_setting(&area->mt_settings, setting);
+}
+
+void
+area_mt_init(struct isis_area *area)
+{
+  struct isis_area_mt_setting *v4_unicast_setting;
+
+  /* MTID 0 is always enabled */
+  v4_unicast_setting = area_new_mt_setting(area, ISIS_MT_IPV4_UNICAST);
+  v4_unicast_setting->enabled = true;
+  add_mt_setting(&area->mt_settings, v4_unicast_setting);
+  area->mt_settings->del = area_free_mt_setting;
+}
+
+void
+area_mt_finish(struct isis_area *area)
+{
+  list_delete(area->mt_settings);
+  area->mt_settings = NULL;
+}
+
+struct isis_area_mt_setting *
+area_get_mt_setting(struct isis_area *area, uint16_t mtid)
+{
+  struct isis_area_mt_setting *setting;
+
+  setting = area_lookup_mt_setting(area, mtid);
+  if (!setting)
+    {
+      setting = area_new_mt_setting(area, mtid);
+      area_add_mt_setting(area, setting);
+    }
+  return setting;
+}
+
+int
+area_write_mt_settings(struct isis_area *area, struct vty *vty)
+{
+  int written = 0;
+  struct listnode *node;
+  struct isis_area_mt_setting *setting;
+
+  for (ALL_LIST_ELEMENTS_RO(area->mt_settings, node, setting))
+    {
+      const char *name = isis_mtid2str(setting->mtid);
+      if (name && setting->enabled)
+        {
+          if (setting->mtid == ISIS_MT_IPV4_UNICAST)
+            continue; /* always enabled, no need to write out config */
+          vty_out (vty, " topology %s%s%s", name,
+                   setting->overload ? " overload" : "",
+                   VTY_NEWLINE);
+          written++;
+        }
+    }
+  return written;
+}
+
+/* Circuit specific MT settings api */
+
+struct isis_circuit_mt_setting*
+circuit_lookup_mt_setting(struct isis_circuit *circuit, uint16_t mtid)
+{
+  return lookup_mt_setting(circuit->mt_settings, mtid);
+}
+
+struct isis_circuit_mt_setting*
+circuit_new_mt_setting(struct isis_circuit *circuit, uint16_t mtid)
+{
+  struct isis_circuit_mt_setting *setting;
+
+  setting = XCALLOC(MTYPE_MT_CIRCUIT_SETTING, sizeof(*setting));
+  setting->mtid = mtid;
+  setting->enabled = true; /* Enabled is default for circuit */
+  return setting;
+}
+
+static void
+circuit_free_mt_setting(void *setting)
+{
+  XFREE(MTYPE_MT_CIRCUIT_SETTING, setting);
+}
+
+void
+circuit_add_mt_setting(struct isis_circuit *circuit,
+                       struct isis_circuit_mt_setting *setting)
+{
+  add_mt_setting(&circuit->mt_settings, setting);
+}
+
+void
+circuit_mt_init(struct isis_circuit *circuit)
+{
+  circuit->mt_settings = list_new();
+  circuit->mt_settings->del = circuit_free_mt_setting;
+}
+
+void
+circuit_mt_finish(struct isis_circuit *circuit)
+{
+  list_delete(circuit->mt_settings);
+  circuit->mt_settings = NULL;
+}
+
+struct isis_circuit_mt_setting*
+circuit_get_mt_setting(struct isis_circuit *circuit, uint16_t mtid)
+{
+  struct isis_circuit_mt_setting *setting;
+
+  setting = circuit_lookup_mt_setting(circuit, mtid);
+  if (!setting)
+    {
+      setting = circuit_new_mt_setting(circuit, mtid);
+      circuit_add_mt_setting(circuit, setting);
+    }
+  return setting;
+}
+
+int
+circuit_write_mt_settings(struct isis_circuit *circuit, struct vty *vty)
+{
+  int written = 0;
+  struct listnode *node;
+  struct isis_circuit_mt_setting *setting;
+
+  for (ALL_LIST_ELEMENTS_RO (circuit->mt_settings, node, setting))
+    {
+      const char *name = isis_mtid2str(setting->mtid);
+      if (name && !setting->enabled)
+        {
+          vty_out (vty, " no isis topology %s%s", name, VTY_NEWLINE);
+          written++;
+        }
+    }
+  return written;
+}
diff --git a/isisd/isis_mt.h b/isisd/isis_mt.h
new file mode 100644
index 000000000..a6f401357
--- /dev/null
+++ b/isisd/isis_mt.h
@@ -0,0 +1,97 @@
+/*
+ * IS-IS Rout(e)ing protocol - Multi Topology Support
+ *
+ * Copyright (C) 2017 Christian Franke
+ *
+ * This file is part of FreeRangeRouting (FRR)
+ *
+ * FRR 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, or (at your option) any
+ * later version.
+ *
+ * FRR 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 FRR; see the file COPYING.  If not, write to the Free
+ * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ */
+#ifndef ISIS_MT_H
+#define ISIS_MT_H
+
+#define ISIS_MT_IPV4_UNICAST   0
+#define ISIS_MT_IPV4_MGMT      1
+#define ISIS_MT_IPV6_UNICAST   2
+#define ISIS_MT_IPV4_MULTICAST 3
+#define ISIS_MT_IPV6_MULTICAST 4
+#define ISIS_MT_IPV6_MGMT      5
+
+#define ISIS_MT_NAMES \
+    "<ipv4-unicast" \
+    "|ipv4-mgmt" \
+    "|ipv6-unicast" \
+    "|ipv4-multicast" \
+    "|ipv6-multicast" \
+    "|ipv6-mgmt" \
+    ">"
+
+#define ISIS_MT_DESCRIPTIONS \
+    "IPv4 unicast topology\n" \
+    "IPv4 management topology\n" \
+    "IPv6 unicast topology\n" \
+    "IPv4 multicast topology\n" \
+    "IPv6 multicast topology\n" \
+    "IPv6 management topology\n"
+
+#define ISIS_MT_INFO_FIELDS \
+  uint16_t mtid;
+
+struct isis_area_mt_setting {
+  ISIS_MT_INFO_FIELDS
+  bool enabled;
+  bool overload;
+};
+
+struct isis_circuit_mt_setting {
+  ISIS_MT_INFO_FIELDS
+  bool enabled;
+};
+
+const char *isis_mtid2str(uint16_t mtid);
+uint16_t isis_str2mtid(const char *name);
+
+struct isis_area;
+struct isis_circuit;
+
+struct isis_area_mt_setting* area_lookup_mt_setting(struct isis_area *area,
+                                                    uint16_t mtid);
+struct isis_area_mt_setting* area_new_mt_setting(struct isis_area *area,
+                                                 uint16_t mtid);
+void area_add_mt_setting(struct isis_area *area,
+                         struct isis_area_mt_setting *setting);
+
+void area_mt_init(struct isis_area *area);
+void area_mt_finish(struct isis_area *area);
+struct isis_area_mt_setting* area_get_mt_setting(struct isis_area *area,
+                                                 uint16_t mtid);
+int area_write_mt_settings(struct isis_area *area, struct vty *vty);
+
+struct isis_circuit_mt_setting* circuit_lookup_mt_setting(
+                                                struct isis_circuit *circuit,
+                                                uint16_t mtid);
+struct isis_circuit_mt_setting* circuit_new_mt_setting(
+                                                struct isis_circuit *circuit,
+                                                uint16_t mtid);
+void circuit_add_mt_setting(struct isis_circuit *circuit,
+                            struct isis_circuit_mt_setting *setting);
+void circuit_mt_init(struct isis_circuit *circuit);
+void circuit_mt_finish(struct isis_circuit *circuit);
+struct isis_circuit_mt_setting* circuit_get_mt_setting(
+                                                struct isis_circuit *circuit,
+                                                uint16_t mtid);
+int circuit_write_mt_settings(struct isis_circuit *circuit, struct vty *vty);
+#endif
diff --git a/isisd/isis_vty.c b/isisd/isis_vty.c
index 721959859..1658ca373 100644
--- a/isisd/isis_vty.c
+++ b/isisd/isis_vty.c
@@ -29,6 +29,7 @@
 #include "isis_circuit.h"
 #include "isis_csm.h"
 #include "isis_misc.h"
+#include "isis_mt.h"
 #include "isisd.h"
 
 static struct isis_circuit *
@@ -1271,6 +1272,48 @@ DEFUN (no_psnp_interval_l2,
   return CMD_SUCCESS;
 }
 
+DEFUN (circuit_topology,
+       circuit_topology_cmd,
+       "isis topology " ISIS_MT_NAMES,
+       "IS-IS commands\n"
+       "Configure interface IS-IS topologies\n"
+       ISIS_MT_DESCRIPTIONS)
+{
+  struct isis_circuit *circuit = isis_circuit_lookup (vty);
+  if (!circuit)
+    return CMD_ERR_NO_MATCH;
+  const char *arg = argv[2]->arg;
+  uint16_t mtid = isis_str2mtid(arg);
+  if (mtid == (uint16_t)-1)
+    {
+      vty_out (vty, "Don't know topology '%s'%s", arg, VTY_NEWLINE);
+      return CMD_ERR_AMBIGUOUS;
+    }
+
+  return isis_circuit_mt_enabled_set(circuit, mtid, true);
+}
+
+DEFUN (no_circuit_topology,
+       no_circuit_topology_cmd,
+       "no isis topology " ISIS_MT_NAMES,
+       NO_STR
+       "IS-IS commands\n"
+       "Configure interface IS-IS topologies\n"
+       ISIS_MT_DESCRIPTIONS)
+{
+  struct isis_circuit *circuit = isis_circuit_lookup (vty);
+  if (!circuit)
+    return CMD_ERR_NO_MATCH;
+  const char *arg = argv[3]->arg;
+  uint16_t mtid = isis_str2mtid(arg);
+  if (mtid == (uint16_t)-1)
+    {
+      vty_out (vty, "Don't know topology '%s'%s", arg, VTY_NEWLINE);
+      return CMD_ERR_AMBIGUOUS;
+    }
+
+  return isis_circuit_mt_enabled_set(circuit, mtid, false);
+}
 
 static int
 validate_metric_style_narrow (struct vty *vty, struct isis_area *area)
@@ -2116,6 +2159,9 @@ isis_vty_init (void)
   install_element (INTERFACE_NODE, &psnp_interval_l2_cmd);
   install_element (INTERFACE_NODE, &no_psnp_interval_l2_cmd);
 
+  install_element (INTERFACE_NODE, &circuit_topology_cmd);
+  install_element (INTERFACE_NODE, &no_circuit_topology_cmd);
+
   install_element (ISIS_NODE, &metric_style_cmd);
   install_element (ISIS_NODE, &no_metric_style_cmd);
 
diff --git a/isisd/isisd.c b/isisd/isisd.c
index f226c4a1f..179e43098 100644
--- a/isisd/isisd.c
+++ b/isisd/isisd.c
@@ -56,6 +56,7 @@
 #include "isisd/isis_zebra.h"
 #include "isisd/isis_events.h"
 #include "isisd/isis_te.h"
+#include "isisd/isis_mt.h"
 
 struct isis *isis = NULL;
 
@@ -156,6 +157,8 @@ isis_area_create (const char *area_tag)
   area->lsp_frag_threshold = 90;
   area->lsp_mtu = DEFAULT_LSP_MTU;
 
+  area_mt_init(area);
+
   area->area_tag = strdup (area_tag);
   listnode_add (isis->area_list, area);
   area->isis = isis;
@@ -296,6 +299,8 @@ isis_area_destroy (struct vty *vty, const char *area_tag)
 
   free (area->area_tag);
 
+  area_mt_finish(area);
+
   XFREE (MTYPE_ISIS_AREA, area);
 
   if (listcount (isis->area_list) == 0)
@@ -307,6 +312,33 @@ isis_area_destroy (struct vty *vty, const char *area_tag)
   return CMD_SUCCESS;
 }
 
+static void
+area_set_mt_enabled(struct isis_area *area, uint16_t mtid, bool enabled)
+{
+  struct isis_area_mt_setting *setting;
+
+  setting = area_get_mt_setting(area, mtid);
+  if (setting->enabled != enabled)
+    {
+      setting->enabled = enabled;
+      lsp_regenerate_schedule (area, IS_LEVEL_1 | IS_LEVEL_2, 0);
+    }
+}
+
+static void
+area_set_mt_overload(struct isis_area *area, uint16_t mtid, bool overload)
+{
+  struct isis_area_mt_setting *setting;
+
+  setting = area_get_mt_setting(area, mtid);
+  if (setting->overload != overload)
+    {
+      setting->overload = overload;
+      if (setting->enabled)
+        lsp_regenerate_schedule (area, IS_LEVEL_1 | IS_LEVEL_2, 0);
+    }
+}
+
 int
 area_net_title (struct vty *vty, const char *net_title)
 {
@@ -1626,6 +1658,61 @@ DEFUN (no_net,
   return area_clear_net_title (vty, argv[idx_word]->arg);
 }
 
+DEFUN (isis_topology,
+       isis_topology_cmd,
+       "topology " ISIS_MT_NAMES " [overload]",
+       "Configure IS-IS topologies\n"
+       ISIS_MT_DESCRIPTIONS
+       "Set overload bit for topology\n")
+{
+  VTY_DECLVAR_CONTEXT (isis_area, area);
+
+  const char *arg = argv[1]->arg;
+  uint16_t mtid = isis_str2mtid(arg);
+  if (mtid == (uint16_t)-1)
+    {
+      vty_out (vty, "Don't know topology '%s'%s", arg, VTY_NEWLINE);
+      return CMD_ERR_AMBIGUOUS;
+    }
+  if (mtid == ISIS_MT_IPV4_UNICAST)
+    {
+      vty_out (vty, "Cannot configure IPv4 unicast topology%s", VTY_NEWLINE);
+      return CMD_ERR_AMBIGUOUS;
+    }
+
+  area_set_mt_enabled(area, mtid, true);
+  area_set_mt_overload(area, mtid, (argc == 3));
+  return CMD_SUCCESS;
+}
+
+DEFUN (no_isis_topology,
+       no_isis_topology_cmd,
+       "no topology " ISIS_MT_NAMES " [overload]",
+       NO_STR
+       "Configure IS-IS topologies\n"
+       ISIS_MT_DESCRIPTIONS
+       "Set overload bit for topology\n")
+{
+  VTY_DECLVAR_CONTEXT (isis_area, area);
+
+  const char *arg = argv[2]->arg;
+  uint16_t mtid = isis_str2mtid(arg);
+  if (mtid == (uint16_t)-1)
+    {
+      vty_out (vty, "Don't know topology '%s'%s", arg, VTY_NEWLINE);
+      return CMD_ERR_AMBIGUOUS;
+    }
+  if (mtid == ISIS_MT_IPV4_UNICAST)
+    {
+      vty_out (vty, "Cannot configure IPv4 unicast topology%s", VTY_NEWLINE);
+      return CMD_ERR_AMBIGUOUS;
+    }
+
+  area_set_mt_enabled(area, mtid, false);
+  area_set_mt_overload(area, mtid, false);
+  return CMD_SUCCESS;
+}
+
 void isis_area_lsp_mtu_set(struct isis_area *area, unsigned int lsp_mtu)
 {
   area->lsp_mtu = lsp_mtu;
@@ -2148,6 +2235,7 @@ isis_config_write (struct vty *vty)
 	    write++;
 	  }
 
+	write += area_write_mt_settings(area, vty);
       }
     isis_mpls_te_config_write_router(vty);
     }
@@ -2254,6 +2342,9 @@ isis_init ()
   install_element (ISIS_NODE, &net_cmd);
   install_element (ISIS_NODE, &no_net_cmd);
 
+  install_element (ISIS_NODE, &isis_topology_cmd);
+  install_element (ISIS_NODE, &no_isis_topology_cmd);
+
   install_element (ISIS_NODE, &log_adj_changes_cmd);
   install_element (ISIS_NODE, &no_log_adj_changes_cmd);
 
diff --git a/isisd/isisd.h b/isisd/isisd.h
index e1d3a69f8..a8cf3673f 100644
--- a/isisd/isisd.h
+++ b/isisd/isisd.h
@@ -120,6 +120,8 @@ struct isis_area
   int ip_circuits;
   /* logging adjacency changes? */
   u_char log_adj_changes;
+  /* multi topology settings */
+  struct list *mt_settings;
   int ipv6_circuits;
   /* Counters */
   u_int32_t circuit_state_changes;