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-rwxr-xr-xsrc/conf_mode/nat.py71
1 files changed, 40 insertions, 31 deletions
diff --git a/src/conf_mode/nat.py b/src/conf_mode/nat.py
index 916f63f09..580a06136 100755
--- a/src/conf_mode/nat.py
+++ b/src/conf_mode/nat.py
@@ -14,6 +14,7 @@
# 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 jmespath
import json
import os
@@ -29,6 +30,7 @@ from vyos import ConfigError
default_config_data = {
'deleted': False,
'destination': [],
+ 'helper_functions': None,
'pre_ct_helper': '',
'pre_ct_conntrack': '',
'out_ct_helper': '',
@@ -47,25 +49,15 @@ def _check_kmod():
raise ConfigError(f'Loading Kernel module {module} failed')
-def get_handler(chain, target):
- """ Get handler number of given chain/target combination. Handler is
- required when adding NAT/Conntrack helper targets """
- tmp = json.loads(cmd('nft -j list table raw'))
- for rule in tmp.get('nftables'):
- # We're only interested in rules - not chains
- if not 'rule' in rule.keys():
+def get_handler(json, chain, target):
+ """ Get nftable rule handler number of given chain/target combination.
+ Handler is required when adding NAT/Conntrack helper targets """
+ for x in json:
+ if x['chain'] != chain:
continue
-
- # Search for chain of interest
- if rule['rule']['chain'] == chain:
- for expr in rule['rule']['expr']:
- # We're only interested in jump targets
- if not 'jump' in expr.keys():
- continue
-
- # Search for target of interest
- if expr['jump']['target'] == target:
- return rule['rule']['handle']
+ if x['target'] != target:
+ continue
+ return x['handle']
return None
@@ -141,24 +133,40 @@ def get_config():
nat = deepcopy(default_config_data)
conf = Config()
+ # read in current nftable (once) for further processing
+ tmp = cmd('nft -j list table raw')
+ nftable_json = json.loads(tmp)
+
+ # condense the full JSON table into a list with only relevand informations
+ pattern = 'nftables[?rule].rule[?expr[].jump].{chain: chain, handle: handle, target: expr[].jump.target | [0]}'
+ condensed_json = jmespath.search(pattern, nftable_json)
+
if not conf.exists(['nat']):
+ nat['helper_functions'] = 'remove'
+
# Retrieve current table handler positions
- nat['pre_ct_ignore'] = get_handler('PREROUTING', 'VYATTA_CT_HELPER')
- nat['pre_ct_conntrack'] = get_handler('PREROUTING', 'NAT_CONNTRACK')
- nat['out_ct_ignore'] = get_handler('OUTPUT', 'VYATTA_CT_HELPER')
- nat['out_ct_conntrack'] = get_handler('OUTPUT', 'NAT_CONNTRACK')
+ nat['pre_ct_ignore'] = get_handler(condensed_json, 'PREROUTING', 'VYATTA_CT_HELPER')
+ nat['pre_ct_conntrack'] = get_handler(condensed_json, 'PREROUTING', 'NAT_CONNTRACK')
+ nat['out_ct_ignore'] = get_handler(condensed_json, 'OUTPUT', 'VYATTA_CT_HELPER')
+ nat['out_ct_conntrack'] = get_handler(condensed_json, 'OUTPUT', 'NAT_CONNTRACK')
nat['deleted'] = True
return nat
- else:
- conf.set_level(['nat'])
- # Retrieve current table handler positions
- nat['pre_ct_ignore'] = get_handler('PREROUTING', 'VYATTA_CT_IGNORE')
- nat['pre_ct_conntrack'] = get_handler('PREROUTING', 'VYATTA_CT_PREROUTING_HOOK')
- nat['out_ct_ignore'] = get_handler('OUTPUT', 'VYATTA_CT_IGNORE')
- nat['out_ct_conntrack'] = get_handler('OUTPUT', 'VYATTA_CT_OUTPUT_HOOK')
+ # check if NAT connection tracking helpers need to be set up - this has to
+ # be done only once
+ if not get_handler(condensed_json, 'PREROUTING', 'NAT_CONNTRACK'):
+ nat['helper_functions'] = 'add'
+
+ # Retrieve current table handler positions
+ nat['pre_ct_ignore'] = get_handler(condensed_json, 'PREROUTING', 'VYATTA_CT_IGNORE')
+ nat['pre_ct_conntrack'] = get_handler(condensed_json, 'PREROUTING', 'VYATTA_CT_PREROUTING_HOOK')
+ nat['out_ct_ignore'] = get_handler(condensed_json, 'OUTPUT', 'VYATTA_CT_IGNORE')
+ nat['out_ct_conntrack'] = get_handler(condensed_json, 'OUTPUT', 'VYATTA_CT_OUTPUT_HOOK')
+
+ # set config level for parsing in NAT configuration
+ conf.set_level(['nat'])
# use a common wrapper function to read in the source / destination
# tree from the config - thus we do not need to replicate almost the
@@ -173,8 +181,9 @@ def verify(nat):
# no need to verify the CLI as NAT is going to be deactivated
return None
- if not (nat['pre_ct_ignore'] or nat['pre_ct_conntrack'] or nat['out_ct_ignore'] or nat['out_ct_conntrack']):
- raise Exception('could not determine nftable ruleset handlers')
+ if nat['helper_functions']:
+ if not (nat['pre_ct_ignore'] or nat['pre_ct_conntrack'] or nat['out_ct_ignore'] or nat['out_ct_conntrack']):
+ raise Exception('could not determine nftable ruleset handlers')
for rule in nat['source']:
interface = rule['interface_out']