1 files changed, 118 insertions, 0 deletions
diff --git a/src/conf_mode/protocols_segment-routing.py b/src/conf_mode/protocols_segment-routing.py
new file mode 100755
index 000000000..d865c2ac0
--- /dev/null
+++ b/src/conf_mode/protocols_segment-routing.py
@@ -0,0 +1,118 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2023 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+
+from sys import exit
+
+from vyos.config import Config
+from vyos.configdict import node_changed
+from vyos.template import render_to_string
+from vyos.utils.dict import dict_search
+from vyos.utils.system import sysctl_write
+from vyos import ConfigError
+from vyos import frr
+from vyos import airbag
+airbag.enable()
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+
+    base = ['protocols', 'segment-routing']
+    sr = conf.get_config_dict(base, key_mangling=('-', '_'),
+                              get_first_key=True,
+                              no_tag_node_value_mangle=True,
+                              with_recursive_defaults=True)
+
+    # FRR has VRF support for different routing daemons. As interfaces belong
+    # to VRFs - or the global VRF, we need to check for changed interfaces so
+    # that they will be properly rendered for the FRR config. Also this eases
+    # removal of interfaces from the running configuration.
+    interfaces_removed = node_changed(conf, base + ['interface'])
+    if interfaces_removed:
+        sr['interface_removed'] = list(interfaces_removed)
+
+    import pprint
+    pprint.pprint(sr)
+    return sr
+
+def verify(sr):
+    if 'srv6' in sr:
+        srv6_enable = False
+        if 'interface' in sr:
+            for interface, interface_config in sr['interface'].items():
+                if 'srv6' in interface_config:
+                    srv6_enable = True
+                    break
+        if not srv6_enable:
+            raise ConfigError('SRv6 should be enabled on at least one interface!')
+    return None
+
+def generate(sr):
+    if not sr:
+        return None
+
+    sr['new_frr_config'] = render_to_string('frr/zebra.segment_routing.frr.j2', sr)
+    return None
+
+def apply(sr):
+    zebra_daemon = 'zebra'
+
+    if 'interface_removed' in sr:
+        for interface in sr['interface_removed']:
+            # Disable processing of IPv6-SR packets
+            sysctl_write(f'net.ipv6.conf.{interface}.seg6_enabled', '0')
+
+    if 'interface' in sr:
+        for interface, interface_config in sr['interface'].items():
+            # Accept or drop SR-enabled IPv6 packets on this interface
+            if 'srv6' in interface_config:
+                sysctl_write(f'net.ipv6.conf.{interface}.seg6_enabled', '1')
+                # Define HMAC policy for ingress SR-enabled packets on this interface
+                # It's a redundant check as HMAC has a default value - but better safe
+                # then sorry
+                tmp = dict_search('srv6.hmac', interface_config)
+                if tmp == 'accept':
+                    sysctl_write(f'net.ipv6.conf.{interface}.seg6_require_hmac', '0')
+                elif tmp == 'drop':
+                    sysctl_write(f'net.ipv6.conf.{interface}.seg6_require_hmac', '1')
+                elif tmp == 'ignore':
+                    sysctl_write(f'net.ipv6.conf.{interface}.seg6_require_hmac', '-1')
+            else:
+                sysctl_write(f'net.ipv6.conf.{interface}.seg6_enabled', '0')
+
+    # Save original configuration prior to starting any commit actions
+    frr_cfg = frr.FRRConfig()
+    frr_cfg.load_configuration(zebra_daemon)
+    frr_cfg.modify_section(r'^segment-routing')
+    if 'new_frr_config' in sr:
+        frr_cfg.add_before(frr.default_add_before, sr['new_frr_config'])
+    frr_cfg.commit_configuration(zebra_daemon)
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)