bgp: T3741: "parameter default no-ipv4-unicast" is now a default option

1 files changed, 77 insertions, 0 deletions

diff --git a/src/migration-scripts/bgp/1-to-2 b/src/migration-scripts/bgp/1-to-2
new file mode 100755
index 000000000..4c6d5ceb8
--- /dev/null
+++ b/src/migration-scripts/bgp/1-to-2
@@ -0,0 +1,77 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2021 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/>.
+
+# T3741: no-ipv4-unicast is now enabled by default
+
+from sys import argv
+from sys import exit
+
+from vyos.configtree import ConfigTree
+from vyos.template import is_ipv4
+
+if (len(argv) < 1):
+    print("Must specify file name!")
+    exit(1)
+
+file_name = argv[1]
+
+with open(file_name, 'r') as f:
+    config_file = f.read()
+
+base = ['protocols', 'bgp']
+config = ConfigTree(config_file)
+
+if not config.exists(base):
+    # Nothing to do
+    exit(0)
+
+# This is now a default option - simply delete it.
+# As it was configured explicitly - we can also bail out early as we need to
+# do nothing!
+if config.exists(base + ['parameters', 'default', 'no-ipv4-unicast']):
+    config.delete(base + ['parameters', 'default', 'no-ipv4-unicast'])
+
+    # Check if the "default" node is now empty, if so - remove it
+    if len(config.list_nodes(base + ['parameters', 'default'])) == 0:
+        config.delete(base + ['parameters', 'default'])
+
+    # Check if the "default" node is now empty, if so - remove it
+    if len(config.list_nodes(base + ['parameters'])) == 0:
+        config.delete(base + ['parameters'])
+
+    exit(0)
+
+# As we now install a new default option into BGP we need to migrate all
+# existing BGP neighbors and restore the old behavior
+if config.exists(base + ['neighbor']):
+    for neighbor in config.list_nodes(base + ['neighbor']):
+        peer_group = base + ['neighbor', neighbor, 'peer-group']
+        if config.exists(peer_group):
+            peer_group_name = config.return_value(peer_group)
+            # peer group enables old behavior for neighbor - bail out
+            if config.exists(base + ['peer-group', peer_group_name, 'address-family', 'ipv4-unicast']):
+                continue
+
+        afi_ipv4 = base + ['neighbor', neighbor, 'address-family', 'ipv4-unicast']
+        if not config.exists(afi_ipv4):
+            config.set(afi_ipv4)
+
+try:
+    with open(file_name, 'w') as f:
+        f.write(config.to_string())
+except OSError as e:
+    print(f'Failed to save the modified config: {e}')
+    exit(1)