T7283: VPP add static NAT support (#24)

* T7283: VPP add static NAT support

Add static mapping NAT implementation

```
set vpp nat44 static rule 10 outbound-interface 'eth0'
set vpp nat44 static rule 10 inbound-interface 'eth1'
set vpp nat44 static rule 10 destination address 192.168.122.10    # optional, if not set outbound interface ip address is used
set vpp nat44 static rule 10 destination port 6545                 # optional
set vpp nat44 static rule 10 protocol tcp|udp|icmp|all             # optional, defaults to "all"
set vpp nat44 static rule 10 translation address 100.64.0.10
set vpp nat44 static rule 10 translation port 64010                # optional
```

* Improve help strings (Daniil Baturin)

---------

Co-authored-by: Daniil Baturin <daniil@baturin.org>

1 files changed, 183 insertions, 0 deletions

diff --git a/src/op_mode/show_vpp_nat44.py b/src/op_mode/show_vpp_nat44.py
new file mode 100644
index 000000000..1aae8164e
--- /dev/null
+++ b/src/op_mode/show_vpp_nat44.py
@@ -0,0 +1,183 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2025 VyOS Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# 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, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+import json
+import sys
+from tabulate import tabulate
+
+import vyos.opmode
+from vyos.configquery import ConfigTreeQuery
+
+from vyos.vpp import VPPControl
+
+
+protocol_map = {
+    0: 'all',
+    1: 'icmp',
+    6: 'tcp',
+    17: 'udp',
+}
+
+
+def _verify(func):
+    """Decorator checks if config for VPP NAT44 exists"""
+    from functools import wraps
+
+    @wraps(func)
+    def _wrapper(*args, **kwargs):
+        config = ConfigTreeQuery()
+        base = 'vpp nat44'
+        if not config.exists(base):
+            raise vyos.opmode.UnconfiguredSubsystem(f'{base} is not configured')
+
+        return func(*args, **kwargs)
+
+    return _wrapper
+
+
+def _get_raw_output_sessions(vpp_api):
+    users: list[dict] = vpp_api.nat44_user_dump()
+    sessions_list: list[dict] = []
+    for user in users:
+        ip_address = str(user._asdict().get('ip_address'))
+        user_sessions_dump = vpp_api.nat44_user_session_v3_dump(ip_address=ip_address)
+        user_sessions = [
+            json.loads(json.dumps(session._asdict(), default=str))
+            for session in user_sessions_dump
+        ]
+        sessions_list.extend(user_sessions)
+    return sorted(sessions_list, key=lambda x: x["inside_ip_address"])
+
+
+def _get_formatted_output_sessions(sessions_list):
+    print('NAT44 ED sessions:')
+    print(f'---------------  {len(sessions_list)} sessions  ---------------')
+    for session in sessions_list:
+        in_ip_addr = session.get('inside_ip_address')
+        in_port = session.get('inside_port')
+        out_ip_addr = session.get('outside_ip_address')
+        out_port = session.get('outside_port')
+        protocol = protocol_map[session.get('protocol')].upper()
+        last_heard = session.get('last_heard')
+        time_since_last_heard = session.get('time_since_last_heard')
+        total_bytes = session.get('total_bytes')
+        total_pkts = session.get('total_pkts')
+        ext_host_address = session.get('ext_host_address')
+        ext_host_port = session.get('ext_host_port')
+        is_timed_out = session.get('is_timed_out')
+
+        print(f'   i2o {in_ip_addr} proto {protocol} port {in_port}')
+        print(f'   o2i {out_ip_addr} proto {protocol} port {out_port}')
+        print(f'      external host {ext_host_address}:{ext_host_port}')
+        print(
+            f'      i2o flow: match: saddr {in_ip_addr} sport {in_port} daddr {ext_host_address} dport {ext_host_port} proto {protocol} rewrite: saddr {out_ip_addr}'
+            + (
+                f' sport {out_port}'
+                if protocol != 'ICMP'
+                else f' daddr {ext_host_address} icmp-id {ext_host_port}'
+            )
+        )
+        print(
+            f'      o2i flow: match: saddr {ext_host_address} sport {ext_host_port} daddr {out_ip_addr} dport {out_port} proto {protocol} rewrite: '
+            + (
+                f'daddr {in_ip_addr} dport {in_port}'
+                if protocol != 'ICMP'
+                else f' saddr {ext_host_address} daddr {in_ip_addr} icmp-id {ext_host_port}'
+            )
+        )
+        print(f'      last heard {last_heard}')
+        print(f'      time since last heard {time_since_last_heard}')
+        print(f'      total packets {total_pkts}, total bytes {total_bytes}')
+        if is_timed_out:
+            print('      session timed out')
+        print('\n')
+
+
+def _get_raw_output_static_rules(vpp_api):
+    nat_static_dump = vpp_api.nat44_static_mapping_dump()
+    rules_list = [
+        json.loads(json.dumps(rule._asdict(), default=str)) for rule in nat_static_dump
+    ]
+    return rules_list
+
+
+def _get_formatted_output_rules(vpp, rules_list):
+    data_entries = []
+    for rule in rules_list:
+        dest_address = rule.get('external_ip_address')
+        dest_port = rule.get('external_port') or ''
+        trans_address = rule.get('local_ip_address')
+        trans_port = rule.get('local_port') or ''
+        protocol = protocol_map[rule.get('protocol', 0)]
+        dest_sh_if_index = rule.get('external_sw_if_index')
+
+        vpp_if_name = vpp.get_interface_name(dest_sh_if_index)
+        if vpp_if_name:
+            dest_address = vpp_if_name
+
+        values = [dest_address, dest_port, trans_address, trans_port, protocol]
+        data_entries.append(values)
+    headers = [
+        'Des_address/interface',
+        'Dest_port',
+        'Trans_address',
+        'Trans_port',
+        'Protocol',
+    ]
+    out = sorted(data_entries, key=lambda x: x[2])
+    return tabulate(out, headers=headers, tablefmt='simple')
+
+
+@_verify
+def show_sessions(raw: bool):
+    vpp = VPPControl()
+    sessions_list: list[dict] = _get_raw_output_sessions(vpp.api)
+
+    if raw:
+        return sessions_list
+
+    else:
+        return _get_formatted_output_sessions(sessions_list)
+
+
+@_verify
+def show_summary(raw: bool):
+    vpp = VPPControl()
+    return vpp.cli_cmd('show nat44 summary').reply
+
+
+@_verify
+def show_static(raw: bool):
+    vpp = VPPControl()
+    rules_list: list[dict] = _get_raw_output_static_rules(vpp.api)
+
+    if raw:
+        return rules_list
+
+    else:
+        return _get_formatted_output_rules(vpp, rules_list)
+
+
+if __name__ == '__main__':
+    try:
+        res = vyos.opmode.run(sys.modules[__name__])
+        if res:
+            print(res)
+    except (ValueError, vyos.opmode.Error) as e:
+        print(e)
+        sys.exit(1)