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

* Rename table to vyos_nat
* Add static NAT smoketest

2 files changed, 67 insertions, 0 deletions

diff --git a/python/vyos/nat.py b/python/vyos/nat.py
index 44dd65372..31bbdc386 100644
--- a/python/vyos/nat.py
+++ b/python/vyos/nat.py
@@ -124,3 +124,65 @@ def parse_nat_rule(rule_conf, rule_id, nat_type, ipv6=False):
     output.append(f'comment "{log_prefix}"')
 
     return " ".join(output)
+
+def parse_nat_static_rule(rule_conf, rule_id, nat_type):
+    output = []
+    log_prefix = ('STATIC-DST' if nat_type == 'destination' else 'STATIC-SRC') + f'-NAT-{rule_id}'
+    log_suffix = ''
+
+    ignore_type_addr = False
+    translation_str = ''
+
+    if 'inbound_interface' in rule_conf:
+        ifname = rule_conf['inbound_interface']
+        ifprefix = 'i' if nat_type == 'destination' else 'o'
+        if ifname != 'any':
+            output.append(f'{ifprefix}ifname "{ifname}"')
+
+    if 'exclude' in rule_conf:
+        translation_str = 'return'
+        log_suffix = '-EXCL'
+    elif 'translation' in rule_conf:
+        translation_prefix = nat_type[:1]
+        translation_output = [f'{translation_prefix}nat']
+        addr = dict_search_args(rule_conf, 'translation', 'address')
+        map_addr =  dict_search_args(rule_conf, 'destination', 'address')
+
+        if nat_type == 'source':
+            addr, map_addr = map_addr, addr # Swap
+
+        if addr and is_ip_network(addr):
+            translation_output.append(f'ip prefix to ip {translation_prefix}addr map {{ {map_addr} : {addr} }}')
+            ignore_type_addr = True
+        elif addr:
+            translation_output.append(f'to {addr}')
+
+        options = []
+        addr_mapping = dict_search_args(rule_conf, 'translation', 'options', 'address_mapping')
+        port_mapping = dict_search_args(rule_conf, 'translation', 'options', 'port_mapping')
+        if addr_mapping == 'persistent':
+            options.append('persistent')
+        if port_mapping and port_mapping != 'none':
+            options.append(port_mapping)
+
+        if options:
+            translation_output.append(",".join(options))
+
+        translation_str = " ".join(translation_output)
+
+    prefix = nat_type[:1]
+    addr = dict_search_args(rule_conf, 'translation' if nat_type == 'source' else nat_type, 'address')
+    if addr and not ignore_type_addr:
+        output.append(f'ip {prefix}addr {addr}')
+
+    output.append('counter')
+
+    if translation_str:
+        output.append(translation_str)
+
+    if 'log' in rule_conf:
+        output.append(f'log prefix "[{log_prefix}{log_suffix}]"')
+
+    output.append(f'comment "{log_prefix}"')
+
+    return " ".join(output)
diff --git a/python/vyos/template.py b/python/vyos/template.py
index d9ff98d2e..0870a0523 100644
--- a/python/vyos/template.py
+++ b/python/vyos/template.py
@@ -621,6 +621,11 @@ def nat_rule(rule_conf, rule_id, nat_type, ipv6=False):
     from vyos.nat import parse_nat_rule
     return parse_nat_rule(rule_conf, rule_id, nat_type, ipv6)
 
+@register_filter('nat_static_rule')
+def nat_static_rule(rule_conf, rule_id, nat_type):
+    from vyos.nat import parse_nat_static_rule
+    return parse_nat_static_rule(rule_conf, rule_id, nat_type)
+
 @register_filter('range_to_regex')
 def range_to_regex(num_range):
     from vyos.range_regex import range_to_regex