1 files changed, 161 insertions, 0 deletions
diff --git a/src/conf_mode/system_conntrack.py b/src/conf_mode/system_conntrack.py
new file mode 100755
index 000000000..9c43640a9
--- /dev/null
+++ b/src/conf_mode/system_conntrack.py
@@ -0,0 +1,161 @@
+#!/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
+import re
+
+from sys import exit
+
+from vyos.config import Config
+from vyos.firewall import find_nftables_rule
+from vyos.firewall import remove_nftables_rule
+from vyos.utils.process import process_named_running
+from vyos.utils.dict import dict_search
+from vyos.utils.process import cmd
+from vyos.utils.process import run
+from vyos.template import render
+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'
+nftables_ct_file = r'/run/nftables-ct.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' : {
+        'nftables' : ['ct helper set "rpc_tcp" tcp dport "{111}" return',
+                      'ct helper set "rpc_udp" udp dport "{111}" return']
+    },
+    'pptp' : {
+        'ko' : ['nf_nat_pptp', 'nf_conntrack_pptp'],
+     },
+    'sip' : {
+        'ko' : ['nf_nat_sip', 'nf_conntrack_sip'],
+     },
+    'sqlnet' : {
+        'nftables' : ['ct helper set "tns_tcp" tcp dport "{1521,1525,1536}" return']
+    },
+    '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,
+                                     with_recursive_defaults=True)
+
+    return conntrack
+
+def verify(conntrack):
+    if dict_search('ignore.rule', conntrack) != None:
+        for rule, rule_config in conntrack['ignore']['rule'].items():
+            if dict_search('destination.port', rule_config) or \
+               dict_search('source.port', rule_config):
+               if 'protocol' not in rule_config or rule_config['protocol'] not in ['tcp', 'udp']:
+                   raise ConfigError(f'Port requires tcp or udp as protocol in rule {rule}')
+
+    return None
+
+def generate(conntrack):
+    render(conntrack_config, 'conntrack/vyos_nf_conntrack.conf.j2', conntrack)
+    render(sysctl_file, 'conntrack/sysctl.conf.j2', conntrack)
+    render(nftables_ct_file, 'conntrack/nftables-ct.j2', conntrack)
+
+    # dry-run newly generated configuration
+    tmp = run(f'nft -c -f {nftables_ct_file}')
+    if tmp > 0:
+        if os.path.exists(nftables_ct_file):
+            os.unlink(nftables_ct_file)
+        raise ConfigError('Configuration file errors encountered!')
+
+    return None
+
+def find_nftables_ct_rule(rule):
+    helper_search = re.search('ct helper set "(\w+)"', rule)
+    if helper_search:
+        rule = helper_search[1]
+    return find_nftables_rule('raw', 'VYOS_CT_HELPER', [rule])
+
+def find_remove_rule(rule):
+    handle = find_nftables_ct_rule(rule)
+    if handle:
+        remove_nftables_rule('raw', 'VYOS_CT_HELPER', handle)
+
+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 'nftables' in module_config:
+                for rule in module_config['nftables']:
+                    find_remove_rule(rule)
+        else:
+            if 'ko' in module_config:
+                for mod in module_config['ko']:
+                    cmd(f'modprobe {mod}')
+            if 'nftables' in module_config:
+                for rule in module_config['nftables']:
+                    if not find_nftables_ct_rule(rule):
+                        cmd(f'nft insert rule ip raw VYOS_CT_HELPER {rule}')
+
+    # Load new nftables ruleset
+    cmd(f'nft -f {nftables_ct_file}')
+
+    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)