From d6108d6e0a14f32d7ee28df01b5a4fcd678acada Mon Sep 17 00:00:00 2001
From: Viacheslav Hletenko <v.gletenko@vyos.io>
Date: Mon, 10 Jun 2024 11:11:02 +0000
Subject: T6442: CGNAT add log for address allocation

Add the configuration command to log current CGNAT allocation

set nat cgnat log-allocation
---
 interface-definitions/nat_cgnat.xml.in |  6 ++++++
 src/conf_mode/nat_cgnat.py             | 30 ++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/interface-definitions/nat_cgnat.xml.in b/interface-definitions/nat_cgnat.xml.in
index fce5e655d..71f4d67b0 100644
--- a/interface-definitions/nat_cgnat.xml.in
+++ b/interface-definitions/nat_cgnat.xml.in
@@ -8,6 +8,12 @@
           <priority>221</priority>
         </properties>
         <children>
+          <leafNode name="log-allocation">
+            <properties>
+              <help>Log IP address and port allocation</help>
+              <valueless/>
+            </properties>
+          </leafNode>
           <node name="pool">
             <properties>
               <help>External and internal pool parameters</help>
diff --git a/src/conf_mode/nat_cgnat.py b/src/conf_mode/nat_cgnat.py
index 957b12c28..bd6855e8b 100755
--- a/src/conf_mode/nat_cgnat.py
+++ b/src/conf_mode/nat_cgnat.py
@@ -16,9 +16,11 @@
 
 import ipaddress
 import jmespath
+import logging
 import os
 
 from sys import exit
+from logging.handlers import SysLogHandler
 
 from vyos.config import Config
 from vyos.template import render
@@ -32,6 +34,18 @@ airbag.enable()
 
 nftables_cgnat_config = '/run/nftables-cgnat.nft'
 
+# Logging
+logger = logging.getLogger('cgnat')
+logger.setLevel(logging.DEBUG)
+
+syslog_handler = SysLogHandler(address="/dev/log")
+syslog_handler.setLevel(logging.INFO)
+
+formatter = logging.Formatter('%(name)s: %(message)s')
+syslog_handler.setFormatter(formatter)
+
+logger.addHandler(syslog_handler)
+
 
 class IPOperations:
     def __init__(self, ip_prefix: str):
@@ -315,6 +329,22 @@ def apply(config):
         return None
     cmd(f'nft --file {nftables_cgnat_config}')
 
+    # Logging allocations
+    if 'log_allocation' in config:
+        allocations = config['proto_map_elements']
+        allocations = allocations.split(',')
+        for allocation in allocations:
+            try:
+                # Split based on the delimiters used in the nft data format
+                internal_host, rest = allocation.split(' : ')
+                external_host, port_range = rest.split(' . ')
+                # Log the parsed data
+                logger.info(
+                    f"Internal host: {internal_host.lstrip()}, external host: {external_host}, Port range: {port_range}")
+            except ValueError as e:
+                # Log error message
+                logger.error(f"Error processing line '{allocation}': {e}")
+
 
 if __name__ == '__main__':
     try:
-- 
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