T3355: always work with UNIX timestamps for dhcp client lease display

ISC dhcp client contains least_update timestamp in human readable format this
makes less sense for an API and also the expiry timestamp is provided in UNIX
time. Convert string (e.g. Sun Jul 30 18:13:44 CEST 2023) to UNIX time (1690733624)

vyos@vyos:~$ ${vyos_op_scripts_dir}/dhcp.py show_client_leases --family inet --interface eth0.10
Interface    eth0.10
IP address   172.16.33.123                  [Active]
Subnet Mask  255.255.255.0
Domain Name  vyos.net
Router       172.16.33.254
Name Server  172.16.254.30
DHCP Server  172.16.33.254
DHCP Server  86400
Last Update  Sun Jul 30 18:13:44 CEST 2023
Expiry       Mon Jul 31 18:13:43 CEST 2023

vyos@vyos:~$ ${vyos_op_scripts_dir}/dhcp.py show_client_leases --family inet --interface eth0.10 --raw
[
    {
        "last_update": 1690733624,
        "reason": "RENEW",
        "interface": "eth0.10",
        "new_expiry": "1690820023",
        "new_dhcp_lease_time": "86400",
        "medium": "",
        "alias_ip_address": "",
        "new_ip_address": "172.16.33.123",
        "new_broadcast_address": "172.16.33.255",
        "new_subnet_mask": "255.255.255.0",
        "new_domain_name": "vyos.net",
        "new_network_number": "172.16.33.0",
        "new_domain_name_servers": "172.16.254.30",
        "new_routers": "172.16.33.254",
        "new_static_routes": "",
        "new_dhcp_server_identifier": "172.16.33.254",
        "new_dhcp_message_type": "5",
        "old_ip_address": "172.16.33.123",
        "old_subnet_mask": "255.255.255.0",
        "old_domain_name": "vyos.net",
        "old_domain_name_servers": "172.16.254.30",
        "old_routers": "172.16.33.254",
        "old_static_routes": ""
    }
]

1 files changed, 13 insertions, 3 deletions

diff --git a/src/op_mode/dhcp.py b/src/op_mode/dhcp.py
index 653e670c5..20ef698bd 100755
--- a/src/op_mode/dhcp.py
+++ b/src/op_mode/dhcp.py
@@ -34,6 +34,8 @@ from vyos.utils.file import read_file
 from vyos.utils.process import cmd
 from vyos.utils.process import is_systemd_service_running
 
+time_string = "%a %b %d %H:%M:%S %Z %Y"
+
 config = ConfigTreeQuery()
 lease_valid_states = ['all', 'active', 'free', 'expired', 'released', 'abandoned', 'reset', 'backup']
 sort_valid_inet = ['end', 'mac', 'hostname', 'ip', 'pool', 'remaining', 'start', 'state']
@@ -291,6 +293,9 @@ def show_server_leases(raw: bool, family: ArgFamily, pool: typing.Optional[str],
 
 
 def _get_raw_client_leases(family='inet', interface=None):
+    from time import mktime
+    from datetime import datetime
+
     lease_dir = '/var/lib/dhcp'
     lease_files = []
     lease_data = []
@@ -309,7 +314,11 @@ def _get_raw_client_leases(family='inet', interface=None):
             for line in f.readlines():
                 line = line.rstrip()
                 if 'last_update' not in tmp:
-                    tmp.update({'last_update' : line})
+                    # ISC dhcp client contains least_update timestamp in human readable
+                    # format this makes less sense for an API and also the expiry
+                    # timestamp is provided in UNIX time. Convert string (e.g. Sun Jul
+                    # 30 18:13:44 CEST 2023) to UNIX time (1690733624)
+                    tmp.update({'last_update' : int(mktime(datetime.strptime(line, time_string).timetuple()))})
                     continue
 
                 k, v = line.split('=')
@@ -344,9 +353,10 @@ def _get_formatted_client_leases(lease_data, family):
         if 'new_dhcp_lease_time' in lease:
             data_entries.append(["DHCP Server", lease['new_dhcp_lease_time']])
         if 'last_update' in lease:
-            data_entries.append(["Last Update", lease['last_update']])
+            tmp = strftime(time_string, localtime(int(lease['last_update'])))
+            data_entries.append(["Last Update", tmp])
         if 'new_expiry' in lease:
-            tmp = strftime('%a %b %d %H:%M:%S %Z %Y', localtime(int(lease['new_expiry'])))
+            tmp = strftime(time_string, localtime(int(lease['new_expiry'])))
             data_entries.append(["Expiry", tmp])
 
         # Add empty marker