T3275: conntrack: Backport XML/Python implementation of conntrack CLI

1 files changed, 139 insertions, 0 deletions

diff --git a/src/conf_mode/conntrack.py b/src/conf_mode/conntrack.py
new file mode 100755
index 000000000..68877f794
--- /dev/null
+++ b/src/conf_mode/conntrack.py
@@ -0,0 +1,139 @@
+#!/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/>.
+
+import os
+
+from sys import exit
+
+from vyos.config import Config
+from vyos.configdict import dict_merge
+from vyos.util import cmd
+from vyos.util import run
+from vyos.util import process_named_running
+from vyos.util import dict_search
+from vyos.template import render
+from vyos.xml import defaults
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+conntrack_config = r'/etc/modprobe.d/vyatta_nf_conntrack.conf'
+sysctl_file = r'/run/sysctl/10-vyos-conntrack.conf'
+
+# Every ALG (Application Layer Gateway) consists of either a Kernel Object
+# also called a Kernel Module/Driver or some rules present in iptables
+module_map = {
+    'ftp' : {
+        'ko' : ['nf_nat_ftp', 'nf_conntrack_ftp'],
+    },
+    'h323' : {
+        'ko' : ['nf_nat_h323', 'nf_conntrack_h323'],
+    },
+    'nfs' : {
+        'iptables' : ['VYATTA_CT_HELPER --table raw --proto tcp --dport 111 --jump CT --helper rpc',
+                      'VYATTA_CT_HELPER --table raw --proto udp --dport 111 --jump CT --helper rpc'],
+    },
+    'pptp' : {
+        'ko' : ['nf_nat_pptp', 'nf_conntrack_pptp'],
+     },
+    'sip' : {
+        'ko' : ['nf_nat_sip', 'nf_conntrack_sip'],
+     },
+    'sqlnet' : {
+        'iptables' : ['VYATTA_CT_HELPER --table raw --proto tcp --dport 1521 --jump CT --helper tns',
+                      'VYATTA_CT_HELPER --table raw --proto tcp --dport 1525 --jump CT --helper tns',
+                      'VYATTA_CT_HELPER --table raw --proto tcp --dport 1536 --jump CT --helper tns'],
+    },
+    'tftp' : {
+        'ko' : ['nf_nat_tftp', 'nf_conntrack_tftp'],
+     },
+}
+
+def resync_conntrackd():
+    tmp = run('/usr/libexec/vyos/conf_mode/conntrack_sync.py')
+    if tmp > 0:
+        print('ERROR: error restarting conntrackd!')
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+    base = ['system', 'conntrack']
+
+    conntrack = conf.get_config_dict(base, key_mangling=('-', '_'),
+                                     get_first_key=True)
+
+    # 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)
+    conntrack = dict_merge(default_values, conntrack)
+
+    return conntrack
+
+def verify(conntrack):
+    return None
+
+def generate(conntrack):
+    render(conntrack_config, 'conntrack/vyos_nf_conntrack.conf.tmpl', conntrack)
+    render(sysctl_file, 'conntrack/sysctl.conf.tmpl', conntrack)
+
+    return None
+
+def apply(conntrack):
+    # Depending on the enable/disable state of the ALG (Application Layer Gateway)
+    # modules we need to either insmod or rmmod the helpers.
+    for module, module_config in module_map.items():
+        if dict_search(f'modules.{module}', conntrack) is None:
+            if 'ko' in module_config:
+                for mod in module_config['ko']:
+                    # Only remove the module if it's loaded
+                    if os.path.exists(f'/sys/module/{mod}'):
+                        cmd(f'rmmod {mod}')
+            if 'iptables' in module_config:
+                for rule in module_config['iptables']:
+                    # Only install iptables rule if it does not exist
+                    tmp = run(f'iptables --check {rule}')
+                    if tmp == 0: cmd(f'iptables --delete {rule}')
+        else:
+            if 'ko' in module_config:
+                for mod in module_config['ko']:
+                    cmd(f'modprobe {mod}')
+            if 'iptables' in module_config:
+                for rule in module_config['iptables']:
+                    # Only install iptables rule if it does not exist
+                    tmp = run(f'iptables --check {rule}')
+                    if tmp > 0: cmd(f'iptables --insert {rule}')
+
+    if process_named_running('conntrackd'):
+        # Reload conntrack-sync daemon to fetch new sysctl values
+        resync_conntrackd()
+
+    # We silently ignore all errors
+    # See: https://bugzilla.redhat.com/show_bug.cgi?id=1264080
+    cmd(f'sysctl -f {sysctl_file}')
+
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)