T4977: Add Babel routing protocol support

This PR adds basic Babel routing protocol support using the implementation in
FRR.

Signed-off-by: Yuxiang Zhu <vfreex@gmail.com>

1 files changed, 163 insertions, 0 deletions

diff --git a/src/conf_mode/protocols_babel.py b/src/conf_mode/protocols_babel.py
new file mode 100755
index 000000000..20821c7f2
--- /dev/null
+++ b/src/conf_mode/protocols_babel.py
@@ -0,0 +1,163 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021-2023 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 dict_merge
+from vyos.configdict import node_changed
+from vyos.configverify import verify_common_route_maps
+from vyos.configverify import verify_access_list
+from vyos.configverify import verify_prefix_list
+from vyos.util import dict_search
+from vyos.xml import defaults
+from vyos.template import render_to_string
+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', 'babel']
+    babel = conf.get_config_dict(base, key_mangling=('-', '_'), get_first_key=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:
+        babel['interface_removed'] = list(interfaces_removed)
+
+    # Bail out early if configuration tree does not exist
+    if not conf.exists(base):
+        babel.update({'deleted' : ''})
+        return babel
+
+    # We have gathered the dict representation of the CLI, but there are default
+    # options which we need to update into the dictionary retrived.
+    default_values = defaults(base)
+
+    # XXX: T2665: we currently have no nice way for defaults under tag nodes,
+    # clean them out and add them manually :(
+    del default_values['interface']
+
+    # merge in remaining default values
+    babel = dict_merge(default_values, babel)
+
+    # We also need some additional information from the config, prefix-lists
+    # and route-maps for instance. They will be used in verify().
+    #
+    # XXX: one MUST always call this without the key_mangling() option! See
+    # vyos.configverify.verify_common_route_maps() for more information.
+    tmp = conf.get_config_dict(['policy'])
+    # Merge policy dict into "regular" config dict
+    babel = dict_merge(tmp, babel)
+    return babel
+
+def verify(babel):
+    if not babel:
+        return None
+
+    # verify distribute_list
+    if "distribute_list" in babel:
+        acl_keys = {
+            "ipv4": [
+                "distribute_list.ipv4.access_list.in",
+                "distribute_list.ipv4.access_list.out",
+            ],
+            "ipv6": [
+                "distribute_list.ipv6.access_list.in",
+                "distribute_list.ipv6.access_list.out",
+            ]
+        }
+        prefix_list_keys = {
+            "ipv4": [
+                "distribute_list.ipv4.prefix_list.in",
+                "distribute_list.ipv4.prefix_list.out",
+            ],
+            "ipv6":[
+                "distribute_list.ipv6.prefix_list.in",
+                "distribute_list.ipv6.prefix_list.out",
+            ]
+        }
+        for address_family in ["ipv4", "ipv6"]:
+            for iface_key in babel["distribute_list"].get(address_family, {}).get("interface", {}).keys():
+                acl_keys[address_family].extend([
+                    f"distribute_list.{address_family}.interface.{iface_key}.access_list.in",
+                    f"distribute_list.{address_family}.interface.{iface_key}.access_list.out"
+                ])
+                prefix_list_keys[address_family].extend([
+                    f"distribute_list.{address_family}.interface.{iface_key}.prefix_list.in",
+                    f"distribute_list.{address_family}.interface.{iface_key}.prefix_list.out"
+                ])
+
+        for address_family, keys in acl_keys.items():
+            for key in keys:
+                acl = dict_search(key, babel)
+                if acl:
+                    verify_access_list(acl, babel, version='6' if address_family == 'ipv6' else '')
+
+        for address_family, keys in prefix_list_keys.items():
+            for key in keys:
+                prefix_list = dict_search(key, babel)
+                if prefix_list:
+                    verify_prefix_list(prefix_list, babel, version='6' if address_family == 'ipv6' else '')
+
+
+def generate(babel):
+    if not babel or 'deleted' in babel:
+        return None
+
+    babel['new_frr_config'] = render_to_string('frr/babeld.frr.j2', babel)
+    return None
+
+def apply(babel):
+    babel_daemon = 'babeld'
+
+    # Save original configuration prior to starting any commit actions
+    frr_cfg = frr.FRRConfig()
+
+    frr_cfg.load_configuration(babel_daemon)
+    frr_cfg.modify_section('^router babel', stop_pattern='^exit', remove_stop_mark=True)
+
+    for key in ['interface', 'interface_removed']:
+        if key not in babel:
+            continue
+        for interface in babel[key]:
+            frr_cfg.modify_section(f'^interface {interface}', stop_pattern='^exit', remove_stop_mark=True)
+
+    if 'new_frr_config' in babel:
+        frr_cfg.add_before(frr.default_add_before, babel['new_frr_config'])
+    frr_cfg.commit_configuration(babel_daemon)
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)