T5530: isis: Adding loop free alternate feature

(cherry picked from commit 7a2b70bd73c8579a885348b93b8addfb20fb006c)

9 files changed, 353 insertions, 3 deletions

diff --git a/data/templates/frr/isisd.frr.j2 b/data/templates/frr/isisd.frr.j2
index dbb8c7305..1e1cc3c27 100644
--- a/data/templates/frr/isisd.frr.j2
+++ b/data/templates/frr/isisd.frr.j2
@@ -165,6 +165,48 @@ advertise-passive-only
 {%         endfor %}
 {%     endfor %}
 {% endif %}
+{% if fast_reroute.lfa is vyos_defined %}
+{%     if fast_reroute.lfa.local is vyos_defined %}
+{%         if fast_reroute.lfa.local.load_sharing.disable.level_1 is vyos_defined %}
+ fast-reroute load-sharing disable level-1
+{%         elif fast_reroute.lfa.local.load_sharing.disable.level_2 is vyos_defined %}
+ fast-reroute load-sharing disable level-2
+{%         elif fast_reroute.lfa.local.load_sharing.disable is vyos_defined %}
+ fast-reroute load-sharing disable
+{%         endif %}
+{%         if fast_reroute.lfa.local.priority_limit is vyos_defined %}
+{%             for priority, priority_limit_options in fast_reroute.lfa.local.priority_limit.items() %}
+{%                 for level in priority_limit_options %}
+ fast-reroute priority-limit {{ priority }} {{ level | replace('_', '-') }}
+{%                 endfor %}                   
+{%             endfor %}
+{%         endif %}
+{%         if fast_reroute.lfa.local.tiebreaker is vyos_defined %}
+{%             for tiebreaker, tiebreaker_options in fast_reroute.lfa.local.tiebreaker.items() %}
+{%                 for index, index_options in tiebreaker_options.items() %}
+{%                     for index_value, index_value_options in index_options.items() %}
+{%                         for level in index_value_options %}
+ fast-reroute lfa tiebreaker {{ tiebreaker | replace('_', '-') }} index {{ index_value }} {{ level | replace('_', '-') }}
+{%                         endfor %}
+{%                     endfor %}
+{%                 endfor %}
+{%             endfor %}
+{%         endif %}
+{%     endif %}
+{%     if fast_reroute.lfa.remote.prefix_list is vyos_defined %}
+{%         for prefix_list, prefix_list_options in fast_reroute.lfa.remote.prefix_list.items() %}
+{%             if prefix_list_options.level_1 is vyos_defined %}
+fast-reroute remote-lfa prefix-list {{ prefix_list }} level-1
+{%             endif %}
+{%             if prefix_list_options.level_2 is vyos_defined %}
+fast-reroute remote-lfa prefix-list {{ prefix_list }} level-2
+{%             endif %}
+{%             if prefix_list is vyos_defined and prefix_list_options.level_1 is not vyos_defined and prefix_list_options.level_2 is not vyos_defined %}
+fast-reroute remote-lfa prefix-list {{ prefix_list }}
+{%             endif %}
+{%         endfor %}
+{%     endif %}
+{% endif %}
 {% if redistribute.ipv4 is vyos_defined %}
 {%     for protocol, protocol_options in redistribute.ipv4.items() %}
 {%         for level, level_config in protocol_options.items() %}
diff --git a/interface-definitions/include/isis/level-1-2-leaf.xml.i b/interface-definitions/include/isis/level-1-2-leaf.xml.i
new file mode 100644
index 000000000..3703da1ed
--- /dev/null
+++ b/interface-definitions/include/isis/level-1-2-leaf.xml.i
@@ -0,0 +1,13 @@
+<!-- include start from isis/level-1-2-leaf.xml.i -->
+<leafNode name="level-1">
+  <properties>
+    <help>Match on IS-IS level-1 routes</help>
+    <valueless/>
+  </properties>
+</leafNode>
+<leafNode name="level-2">
+  <properties>
+    <help>Match on IS-IS level-2 routes</help>
+    <valueless/>
+  </properties>
+</leafNode>
\ No newline at end of file
diff --git a/interface-definitions/include/isis/lfa-local.xml.i b/interface-definitions/include/isis/lfa-local.xml.i
new file mode 100644
index 000000000..c5bf6a3eb
--- /dev/null
+++ b/interface-definitions/include/isis/lfa-local.xml.i
@@ -0,0 +1,128 @@
+<!-- include start from isis/lfa-local.xml.i -->
+<node name="local">
+  <properties>
+    <help>Local loop free alternate options</help>
+  </properties>
+  <children>
+    <node name="load-sharing">
+      <properties>
+        <help>Load share prefixes across multiple backups</help>
+      </properties>
+      <children>
+        <node name="disable">
+          <properties>
+            <help>Disable load sharing</help>
+          </properties>
+          <children>
+            #include <include/isis/level-1-2-leaf.xml.i>
+          </children>
+        </node>
+      </children>
+    </node>
+    <node name="priority-limit">
+      <properties>
+        <help>Limit backup computation up to the prefix priority</help>
+      </properties>
+      <children>
+        <node name="medium">
+          <properties>
+            <help>Compute for critical, high, and medium priority prefixes</help>
+          </properties>
+          <children>
+            #include <include/isis/level-1-2-leaf.xml.i>
+          </children>
+        </node>
+        <node name="high">
+          <properties>
+            <help>Compute for critical, and high priority prefixes</help>
+          </properties>
+          <children>
+            #include <include/isis/level-1-2-leaf.xml.i>
+          </children>
+        </node>
+        <node name="critical">
+          <properties>
+            <help>Compute for critical priority prefixes only</help>
+          </properties>
+          <children>
+            #include <include/isis/level-1-2-leaf.xml.i>
+          </children>
+        </node>
+      </children>
+    </node>
+    <node name="tiebreaker">
+      <properties>
+        <help>Configure tiebreaker for multiple backups</help>
+      </properties>
+      <children>
+        <node name="downstream">
+          <properties>
+            <help>Prefer backup path via downstream node</help>
+          </properties>
+          <children>
+            <tagNode name="index">
+              <properties>
+                <help>Set preference order among tiebreakers</help>
+                <valueHelp>
+                  <format>u32:1-255</format>
+                    <description>The index integer value</description>
+                </valueHelp>
+                <constraint>
+                  <validator name="numeric" argument="--range 1-255"/>
+                </constraint>
+              </properties>
+              <children>
+                #include <include/isis/level-1-2-leaf.xml.i>
+              </children>
+            </tagNode>
+          </children>
+        </node>
+        <node name="lowest-backup-metric">
+          <properties>
+            <help>Prefer backup path with lowest total metric</help>
+          </properties>
+          <children>
+            <tagNode name="index">
+              <properties>
+                <help>Set preference order among tiebreakers</help>
+                <valueHelp>
+                  <format>u32:1-255</format>
+                    <description>The index integer value</description>
+                </valueHelp>
+                <constraint>
+                  <validator name="numeric" argument="--range 1-255"/>
+                </constraint>
+              </properties>
+              <children>
+                #include <include/isis/level-1-2-leaf.xml.i>
+              </children>
+            </tagNode>
+          </children>
+        </node>
+        <node name="node-protecting">
+          <properties>
+            <help>Prefer node protecting backup path</help>
+          </properties>
+          <children>
+            <tagNode name="index">
+              <properties>
+                <help>Set preference order among tiebreakers</help>
+                <valueHelp>
+                  <format>u32:1-255</format>
+                    <description>The index integer value</description>
+                </valueHelp>
+                <constraint>
+                  <validator name="numeric" argument="--range 1-255"/>
+                </constraint>
+              </properties>
+              <children>
+                #include <include/isis/level-1-2-leaf.xml.i>
+              </children>
+            </tagNode>
+          </children>
+        </node>
+      </children>
+    </node>
+  </children>
+</node>
+<!-- include end -->
\ No newline at end of file
diff --git a/interface-definitions/include/isis/lfa-protocol.xml.i b/interface-definitions/include/isis/lfa-protocol.xml.i
new file mode 100644
index 000000000..cfb1a6dc1
--- /dev/null
+++ b/interface-definitions/include/isis/lfa-protocol.xml.i
@@ -0,0 +1,11 @@
+<!-- include start from isis/lfa-protocol.xml.i -->
+<node name="lfa">
+  <properties>
+    <help>Loop free alternate functionality</help>
+  </properties>
+  <children>
+    #include <include/isis/lfa-remote.xml.i>
+    #include <include/isis/lfa-local.xml.i>
+  </children>
+</node>
+<!-- include end -->
\ No newline at end of file
diff --git a/interface-definitions/include/isis/lfa-remote.xml.i b/interface-definitions/include/isis/lfa-remote.xml.i
new file mode 100644
index 000000000..8434e35bf
--- /dev/null
+++ b/interface-definitions/include/isis/lfa-remote.xml.i
@@ -0,0 +1,28 @@
+<!-- include start from isis/lfa-remote.xml.i -->
+<node name="remote">
+  <properties>
+    <help>Remote loop free alternate options</help>
+  </properties>
+  <children>
+    <tagNode name="prefix-list">
+      <properties>
+        <help>Filter PQ node router ID based on prefix list</help>
+        <completionHelp>
+          <path>policy prefix-list</path>
+        </completionHelp>
+        <valueHelp>
+          <format>txt</format>
+          <description>Name of IPv4/IPv6 prefix-list</description>
+        </valueHelp>
+        <constraint>
+          #include <include/constraint/alpha-numeric-hyphen-underscore.xml.i>
+        </constraint>
+        <constraintErrorMessage>Name of prefix-list can only contain alpha-numeric letters, hyphen and underscores</constraintErrorMessage>
+      </properties>
+      <children>
+        #include <include/isis/level-1-2-leaf.xml.i>
+      </children>
+    </tagNode>
+  </children>
+</node>
+<!-- include end -->
\ No newline at end of file
diff --git a/interface-definitions/include/isis/protocol-common-config.xml.i b/interface-definitions/include/isis/protocol-common-config.xml.i
index 648f2b319..404f03cb5 100644
--- a/interface-definitions/include/isis/protocol-common-config.xml.i
+++ b/interface-definitions/include/isis/protocol-common-config.xml.i
@@ -165,6 +165,14 @@
   </properties>
 </leafNode>
 #include <include/isis/ldp-sync-protocol.xml.i>
+<node name="fast-reroute">
+  <properties>
+    <help>IS-IS fast reroute configuration</help>
+  </properties>
+  <children>
+    #include <include/isis/lfa-protocol.xml.i>
+  </children>
+</node>
 <leafNode name="net">
   <properties>
     <help>A Network Entity Title for this process (ISO only)</help>
diff --git a/op-mode-definitions/include/isis-common.xml.i b/op-mode-definitions/include/isis-common.xml.i
index e94d868e8..493a56633 100644
--- a/op-mode-definitions/include/isis-common.xml.i
+++ b/op-mode-definitions/include/isis-common.xml.i
@@ -17,6 +17,33 @@
   </properties>
   <command>${vyos_op_scripts_dir}/vtysh_wrapper.sh $@</command>
 </tagNode>
+<node name="fast-reroute">
+  <properties>
+    <help>Show IS-IS fast reroute/loop free alternate (lfa) information</help>
+  </properties>
+  <children>
+    <node name="summary">
+      <properties>
+        <help>Show summary of fast reroute/loop free alternate (lfa) information</help>
+      </properties>
+      <children>
+        <leafNode name="level-1">
+          <properties>
+            <help>Show level-1 specific fast reroute/loop free alternate (lfa) information</help>
+          </properties>
+          <command>${vyos_op_scripts_dir}/vtysh_wrapper.sh $@</command>
+        </leafNode>
+        <leafNode name="level-2">
+          <properties>
+            <help>Show level-2 specific fast reroute/loop free alternate (lfa) information</help>
+          </properties>
+          <command>${vyos_op_scripts_dir}/vtysh_wrapper.sh $@</command>
+        </leafNode>
+      </children>
+      <command>${vyos_op_scripts_dir}/vtysh_wrapper.sh $@</command>
+    </node>
+  </children>
+</node>
 <leafNode name="hostname">
   <properties>
     <help>Show IS-IS dynamic hostname mapping</help>
diff --git a/smoketest/scripts/cli/test_protocols_isis.py b/smoketest/scripts/cli/test_protocols_isis.py
index c82836b72..94f4ec5c9 100755
--- a/smoketest/scripts/cli/test_protocols_isis.py
+++ b/smoketest/scripts/cli/test_protocols_isis.py
@@ -329,5 +329,65 @@ class TestProtocolsISIS(VyOSUnitTestSHIM.TestCase):
             self.assertIn(f' ipv6 router isis {domain}', tmp)
             self.assertIn(f' no isis mpls ldp-sync', tmp)
 
+    def test_isis_09_lfa(self):
+        prefix_list = 'lfa-prefix-list-test-1'
+        prefix_list_address = '192.168.255.255/32'
+        interface = 'lo'
+
+        self.cli_set(base_path + ['net', net])
+        self.cli_set(base_path + ['interface', interface])
+        self.cli_set(['policy', 'prefix-list', prefix_list, 'rule', '1', 'action', 'permit'])
+        self.cli_set(['policy', 'prefix-list', prefix_list, 'rule', '1', 'prefix', prefix_list_address])
+        
+        # Commit main ISIS changes
+        self.cli_commit()
+
+        # Add remote portion of LFA with prefix list with validation
+        for level in ['level-1', 'level-2']:
+            self.cli_set(base_path + ['fast-reroute', 'lfa', 'remote', 'prefix-list', prefix_list, level])
+            self.cli_commit()
+            tmp = self.getFRRconfig(f'router isis {domain}', daemon='isisd')
+            self.assertIn(f' net {net}', tmp)
+            self.assertIn(f' fast-reroute remote-lfa prefix-list {prefix_list} {level}', tmp)
+            self.cli_delete(base_path + ['fast-reroute'])
+            self.cli_commit()
+
+        # Add local portion of LFA load-sharing portion with validation
+        for level in ['level-1', 'level-2']:
+            self.cli_set(base_path + ['fast-reroute', 'lfa', 'local', 'load-sharing', 'disable', level])
+            self.cli_commit()
+            tmp = self.getFRRconfig(f'router isis {domain}', daemon='isisd')
+            self.assertIn(f' net {net}', tmp)
+            self.assertIn(f' fast-reroute load-sharing disable {level}', tmp)
+            self.cli_delete(base_path + ['fast-reroute'])
+            self.cli_commit()
+
+        # Add local portion of LFA priority-limit portion with validation
+        for priority in ['critical', 'high', 'medium']:
+            for level in ['level-1', 'level-2']:
+                self.cli_set(base_path + ['fast-reroute', 'lfa', 'local', 'priority-limit', priority, level])
+                self.cli_commit()
+                tmp = self.getFRRconfig(f'router isis {domain}', daemon='isisd')
+                self.assertIn(f' net {net}', tmp)
+                self.assertIn(f' fast-reroute priority-limit {priority} {level}', tmp)
+                self.cli_delete(base_path + ['fast-reroute'])
+                self.cli_commit()
+
+        # Add local portion of LFA tiebreaker portion with validation
+        index = '100'
+        for tiebreaker in ['downstream','lowest-backup-metric','node-protecting']:
+            for level in ['level-1', 'level-2']:
+                self.cli_set(base_path + ['fast-reroute', 'lfa', 'local', 'tiebreaker', tiebreaker, 'index', index, level])
+                self.cli_commit()
+                tmp = self.getFRRconfig(f'router isis {domain}', daemon='isisd')
+                self.assertIn(f' net {net}', tmp)
+                self.assertIn(f' fast-reroute lfa tiebreaker {tiebreaker} index {index} {level}', tmp)
+                self.cli_delete(base_path + ['fast-reroute'])
+                self.cli_commit()
+
+        # Clean up and remove prefix list
+        self.cli_delete(['policy', 'prefix-list', prefix_list])
+        self.cli_commit()
+
 if __name__ == '__main__':
-    unittest.main(verbosity=2)
+    unittest.main(verbosity=2)
\ No newline at end of file
diff --git a/src/conf_mode/protocols_isis.py b/src/conf_mode/protocols_isis.py
index e00c58ee4..ce67ccff7 100755
--- a/src/conf_mode/protocols_isis.py
+++ b/src/conf_mode/protocols_isis.py
@@ -48,7 +48,8 @@ def get_config(config=None):
     # eqivalent of the C foo ? 'a' : 'b' statement
     base = vrf and ['vrf', 'name', vrf, 'protocols', 'isis'] or base_path
     isis = conf.get_config_dict(base, key_mangling=('-', '_'),
-                                get_first_key=True)
+                                get_first_key=True,
+                                no_tag_node_value_mangle=True)
 
     # Assign the name of our VRF context. This MUST be done before the return
     # statement below, else on deletion we will delete the default instance
@@ -219,6 +220,38 @@ def verify(isis):
                 if ("explicit_null" in prefix_config['index']) and ("no_php_flag" in prefix_config['index']):
                     raise ConfigError(f'Segment routing prefix {prefix} cannot have both explicit-null '\
                                       f'and no-php-flag configured at the same time.')
+                
+    # Check for LFA tiebreaker index duplication
+    if dict_search('fast_reroute.lfa.local.tiebreaker', isis):
+        comparison_dictionary = {}
+        for item, item_options in isis['fast_reroute']['lfa']['local']['tiebreaker'].items():
+            for index, index_options in item_options.items():
+                for index_value, index_value_options in index_options.items():
+                    if index_value not in comparison_dictionary.keys():
+                        comparison_dictionary[index_value] = [item]
+                    else:
+                        comparison_dictionary[index_value].append(item)
+        for index, index_length in comparison_dictionary.items():
+            if int(len(index_length)) > 1:
+                raise ConfigError(f'LFA index {index} cannot have more than one tiebreaker configured.')
+
+    # Check for LFA priority-limit configured multiple times per level
+    if dict_search('fast_reroute.lfa.local.priority_limit', isis):
+        comparison_dictionary = {}
+        for priority, priority_options in isis['fast_reroute']['lfa']['local']['priority_limit'].items():
+            for level, level_options in priority_options.items():
+                if level not in comparison_dictionary.keys():
+                    comparison_dictionary[level] = [priority]
+                else:
+                    comparison_dictionary[level].append(priority)
+            for level, level_length in comparison_dictionary.items():
+                if int(len(level_length)) > 1:
+                    raise ConfigError(f'LFA priority-limit on {level.replace("_", "-")} cannot have more than one priority configured.')
+
+    # Check for LFA remote prefix list configured with more than one list
+    if dict_search('fast_reroute.lfa.remote.prefix_list', isis):
+        if int(len(isis['fast_reroute']['lfa']['remote']['prefix_list'].items())) > 1:
+            raise ConfigError(f'LFA remote prefix-list has more than one configured. Cannot have more than one configured.')
 
     return None
 
@@ -265,4 +298,4 @@ if __name__ == '__main__':
         apply(c)
     except ConfigError as e:
         print(e)
-        exit(1)
+        exit(1)
\ No newline at end of file