nat: T4605: Refactor NAT to use python module for parsing rules

* Rename table to vyos_nat
* Refactor tests to use `verify_nftables` format

2 files changed, 68 insertions, 74 deletions

diff --git a/smoketest/scripts/cli/test_load_balancning_wan.py b/smoketest/scripts/cli/test_load_balancning_wan.py
index 303dece86..23020b9b1 100755
--- a/smoketest/scripts/cli/test_load_balancning_wan.py
+++ b/smoketest/scripts/cli/test_load_balancning_wan.py
@@ -177,6 +177,7 @@ class TestLoadBalancingWan(VyOSUnitTestSHIM.TestCase):
 }"""
         nat_vyos_pre_snat_hook = """table ip nat {
 	chain VYOS_PRE_SNAT_HOOK {
+		type nat hook postrouting priority srcnat - 1; policy accept;
 		counter jump WANLOADBALANCE
 		return
 	}
diff --git a/smoketest/scripts/cli/test_nat.py b/smoketest/scripts/cli/test_nat.py
index 408facfb3..5863409be 100755
--- a/smoketest/scripts/cli/test_nat.py
+++ b/smoketest/scripts/cli/test_nat.py
@@ -26,6 +26,7 @@ from vyos.util import dict_search
 base_path = ['nat']
 src_path = base_path + ['source']
 dst_path = base_path + ['destination']
+static_path = base_path + ['static']
 
 class TestNAT(VyOSUnitTestSHIM.TestCase):
     @classmethod
@@ -40,10 +41,24 @@ class TestNAT(VyOSUnitTestSHIM.TestCase):
         self.cli_delete(base_path)
         self.cli_commit()
 
+    def verify_nftables(self, nftables_search, table, inverse=False, args=''):
+        nftables_output = cmd(f'sudo nft {args} list table {table}')
+
+        for search in nftables_search:
+            matched = False
+            for line in nftables_output.split("\n"):
+                if all(item in line for item in search):
+                    matched = True
+                    break
+            self.assertTrue(not matched if inverse else matched, msg=search)
+
     def test_snat(self):
         rules = ['100', '110', '120', '130', '200', '210', '220', '230']
         outbound_iface_100 = 'eth0'
         outbound_iface_200 = 'eth1'
+
+        nftables_search = ['jump VYOS_PRE_SNAT_HOOK']
+
         for rule in rules:
             network = f'192.168.{rule}.0/24'
             # depending of rule order we check either for source address for NAT
@@ -52,51 +67,16 @@ class TestNAT(VyOSUnitTestSHIM.TestCase):
                 self.cli_set(src_path + ['rule', rule, 'source', 'address', network])
                 self.cli_set(src_path + ['rule', rule, 'outbound-interface', outbound_iface_100])
                 self.cli_set(src_path + ['rule', rule, 'translation', 'address', 'masquerade'])
+                nftables_search.append([f'saddr {network}', f'oifname "{outbound_iface_100}"', 'masquerade'])
             else:
                 self.cli_set(src_path + ['rule', rule, 'destination', 'address', network])
                 self.cli_set(src_path + ['rule', rule, 'outbound-interface', outbound_iface_200])
                 self.cli_set(src_path + ['rule', rule, 'exclude'])
+                nftables_search.append([f'daddr {network}', f'oifname "{outbound_iface_200}"', 'return'])
 
         self.cli_commit()
 
-        tmp = cmd('sudo nft -j list chain ip nat POSTROUTING')
-        data_json = jmespath.search('nftables[?rule].rule[?chain]', json.loads(tmp))
-
-        for idx in range(0, len(data_json)):
-            data = data_json[idx]
-            if idx == 0:
-                self.assertEqual(data['chain'], 'POSTROUTING')
-                self.assertEqual(data['family'], 'ip')
-                self.assertEqual(data['table'], 'nat')
-
-                jump_target = dict_search('jump.target', data['expr'][1])
-                self.assertEqual(jump_target,'VYOS_PRE_SNAT_HOOK')
-            else:
-                rule = str(rules[idx - 1])
-                network = f'192.168.{rule}.0/24'
-
-                self.assertEqual(data['chain'], 'POSTROUTING')
-                self.assertEqual(data['comment'], f'SRC-NAT-{rule}')
-                self.assertEqual(data['family'], 'ip')
-                self.assertEqual(data['table'], 'nat')
-
-                iface = dict_search('match.right', data['expr'][0])
-                direction = dict_search('match.left.payload.field', data['expr'][1])
-                address = dict_search('match.right.prefix.addr', data['expr'][1])
-                mask = dict_search('match.right.prefix.len', data['expr'][1])
-
-                if int(rule) < 200:
-                    self.assertEqual(direction, 'saddr')
-                    self.assertEqual(iface, outbound_iface_100)
-                    # check for masquerade keyword
-                    self.assertIn('masquerade', data['expr'][3])
-                else:
-                    self.assertEqual(direction, 'daddr')
-                    self.assertEqual(iface, outbound_iface_200)
-                    # check for return keyword due to 'exclude'
-                    self.assertIn('return', data['expr'][3])
-
-                self.assertEqual(f'{address}/{mask}', network)
+        self.verify_nftables(nftables_search, 'ip vyos_nat')
 
     def test_dnat(self):
         rules = ['100', '110', '120', '130', '200', '210', '220', '230']
@@ -105,56 +85,29 @@ class TestNAT(VyOSUnitTestSHIM.TestCase):
         inbound_proto_100 = 'udp'
         inbound_proto_200 = 'tcp'
 
+        nftables_search = ['jump VYOS_PRE_DNAT_HOOK']
+
         for rule in rules:
             port = f'10{rule}'
             self.cli_set(dst_path + ['rule', rule, 'source', 'port', port])
             self.cli_set(dst_path + ['rule', rule, 'translation', 'address', '192.0.2.1'])
             self.cli_set(dst_path + ['rule', rule, 'translation', 'port', port])
+            rule_search = [f'dnat to 192.0.2.1:{port}']
             if int(rule) < 200:
                 self.cli_set(dst_path + ['rule', rule, 'protocol', inbound_proto_100])
                 self.cli_set(dst_path + ['rule', rule, 'inbound-interface', inbound_iface_100])
+                rule_search.append(f'{inbound_proto_100} sport {port}')
+                rule_search.append(f'iifname "{inbound_iface_100}"')
             else:
                 self.cli_set(dst_path + ['rule', rule, 'protocol', inbound_proto_200])
                 self.cli_set(dst_path + ['rule', rule, 'inbound-interface', inbound_iface_200])
+                rule_search.append(f'iifname "{inbound_iface_200}"')
 
-        self.cli_commit()
-
-        tmp = cmd('sudo nft -j list chain ip nat PREROUTING')
-        data_json = jmespath.search('nftables[?rule].rule[?chain]', json.loads(tmp))
-
-        for idx in range(0, len(data_json)):
-            data = data_json[idx]
-            if idx == 0:
-                self.assertEqual(data['chain'], 'PREROUTING')
-                self.assertEqual(data['family'], 'ip')
-                self.assertEqual(data['table'], 'nat')
+            nftables_search.append(rule_search)
 
-                jump_target = dict_search('jump.target', data['expr'][1])
-                self.assertEqual(jump_target,'VYOS_PRE_DNAT_HOOK')
-            else:
+        self.cli_commit()
 
-                rule = str(rules[idx - 1])
-                port = int(f'10{rule}')
-
-                self.assertEqual(data['chain'], 'PREROUTING')
-                self.assertEqual(data['comment'].split()[0], f'DST-NAT-{rule}')
-                self.assertEqual(data['family'], 'ip')
-                self.assertEqual(data['table'], 'nat')
-
-                iface = dict_search('match.right', data['expr'][0])
-                direction = dict_search('match.left.payload.field', data['expr'][1])
-                protocol = dict_search('match.left.payload.protocol', data['expr'][1])
-                dnat_addr = dict_search('dnat.addr', data['expr'][3])
-                dnat_port = dict_search('dnat.port', data['expr'][3])
-
-                self.assertEqual(direction, 'sport')
-                self.assertEqual(dnat_addr, '192.0.2.1')
-                self.assertEqual(dnat_port, port)
-                if int(rule) < 200:
-                    self.assertEqual(iface, inbound_iface_100)
-                    self.assertEqual(protocol, inbound_proto_100)
-                else:
-                    self.assertEqual(iface, inbound_iface_200)
+        self.verify_nftables(nftables_search, 'ip vyos_nat')
 
     def test_snat_required_translation_address(self):
         # T2813: Ensure translation address is specified
@@ -193,8 +146,48 @@ class TestNAT(VyOSUnitTestSHIM.TestCase):
         # without any rule
         self.cli_set(src_path)
         self.cli_set(dst_path)
+        self.cli_set(static_path)
+        self.cli_commit()
+
+    def test_dnat_without_translation_address(self):
+        self.cli_set(dst_path + ['rule', '1', 'inbound-interface', 'eth1'])
+        self.cli_set(dst_path + ['rule', '1', 'destination', 'port', '443'])
+        self.cli_set(dst_path + ['rule', '1', 'protocol', 'tcp'])
+        self.cli_set(dst_path + ['rule', '1', 'translation', 'port', '443'])
+
+        self.cli_commit()
+
+        nftables_search = [
+            ['iifname "eth1"', 'tcp dport 443', 'dnat to :443']
+        ]
+
+        self.verify_nftables(nftables_search, 'ip vyos_nat')
+
+    def test_static_nat(self):
+        dst_addr_1 = '10.0.1.1'
+        translate_addr_1 = '192.168.1.1'
+        dst_addr_2 = '203.0.113.0/24'
+        translate_addr_2 = '192.0.2.0/24'
+        ifname = 'eth0'
+
+        self.cli_set(static_path + ['rule', '10', 'destination', 'address', dst_addr_1])
+        self.cli_set(static_path + ['rule', '10', 'inbound-interface', ifname])
+        self.cli_set(static_path + ['rule', '10', 'translation', 'address', translate_addr_1])
+
+        self.cli_set(static_path + ['rule', '20', 'destination', 'address', dst_addr_2])
+        self.cli_set(static_path + ['rule', '20', 'inbound-interface', ifname])
+        self.cli_set(static_path + ['rule', '20', 'translation', 'address', translate_addr_2])
+
         self.cli_commit()
 
+        nftables_search = [
+            [f'iifname "{ifname}"', f'ip daddr {dst_addr_1}', f'dnat to {translate_addr_1}'],
+            [f'oifname "{ifname}"', f'ip saddr {translate_addr_1}', f'snat to {dst_addr_1}'],
+            [f'iifname "{ifname}"', f'dnat ip prefix to ip daddr map {{ {dst_addr_2} : {translate_addr_2} }}'],
+            [f'oifname "{ifname}"', f'snat ip prefix to ip daddr map {{ {translate_addr_2} : {dst_addr_2} }}']
+        ]
+
+        self.verify_nftables(nftables_search, 'ip vyos_nat')
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)