From 9f20bee81c0a0f4632aa152297d0fdf89139d6af Mon Sep 17 00:00:00 2001
From: Jernej Jakob <jernej.jakob@gmail.com>
Date: Fri, 19 Jul 2019 02:28:53 +0200
Subject: T1376: improve show_dhcp and show_dhcpv6

---
 src/op_mode/show_dhcpv6.py | 61 ++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 51 insertions(+), 10 deletions(-)

(limited to 'src/op_mode/show_dhcpv6.py')

diff --git a/src/op_mode/show_dhcpv6.py b/src/op_mode/show_dhcpv6.py
index f1f5a6a55..1a6ee62e6 100755
--- a/src/op_mode/show_dhcpv6.py
+++ b/src/op_mode/show_dhcpv6.py
@@ -21,6 +21,8 @@ import ipaddress
 import tabulate
 import sys
 import collections
+import os
+from datetime import datetime
 
 from vyos.config import Config
 from isc_dhcp_leases import Lease, IscDhcpLeases
@@ -33,6 +35,7 @@ lease_display_fields['ip'] = 'IPv6 address'
 lease_display_fields['state'] = 'State'
 lease_display_fields['last_comm'] = 'Last communication'
 lease_display_fields['expires'] = 'Lease expiration'
+lease_display_fields['remaining'] = 'Remaining'
 lease_display_fields['type'] = 'Type'
 lease_display_fields['pool'] = 'Pool'
 lease_display_fields['iaid_duid'] = 'IAID_DUID'
@@ -57,20 +60,35 @@ def format_hex_string(in_str):
 
     return out_str
 
+def utc_to_local(utc_dt):
+    return datetime.fromtimestamp((utc_dt - datetime(1970,1,1)).total_seconds())
+
 def get_lease_data(lease):
     data = {}
 
-    # End time may not be present in backup leases
+    # isc-dhcp lease times are in UTC so we need to convert them to local time to display
     try:
-        data["expires"] = lease.end.strftime("%Y/%m/%d %H:%M:%S")
+        data["expires"] = utc_to_local(lease.end).strftime("%Y/%m/%d %H:%M:%S")
     except:
         data["expires"] = ""
 
     try:
-        data["last_comm"] = lease.last_communication.strftime("%Y/%m/%d %H:%M:%S")
+        data["last_comm"] = utc_to_local(lease.last_communication).strftime("%Y/%m/%d %H:%M:%S")
     except:
         data["last_comm"] = ""
 
+    try:
+        data["remaining"] = lease.end - datetime.utcnow()
+        # negative timedelta prints wrong so bypass it
+        if (data["remaining"].days >= 0):
+            # substraction gives us a timedelta object which can't be formatted with strftime
+            # so we use str(), split gets rid of the microseconds
+            data["remaining"] = str(data["remaining"]).split('.')[0]
+        else:
+            data["remaining"] = ""
+    except:
+        data["remaining"] = ""
+
     # isc-dhcp records lease declarations as ia_{na|ta|pd} IAID_DUID {...}
     # where IAID_DUID is the combined IAID and DUID
     data["iaid_duid"] = format_hex_string(lease.host_identifier_string)
@@ -91,16 +109,35 @@ def get_lease_data(lease):
 def get_leases(leases, state, pool=None, sort='ip'):
     leases = IscDhcpLeases(lease_file).get()
 
-    if state != 'all':
-        leases = list(filter(lambda x: x.binding_state == state, leases))
+    # filter leases by state
+    if 'all' not in state:
+        leases = list(filter(lambda x: x.binding_state in state, leases))
 
-    # filter lease by pool name
+    # filter leases by pool name
     if pool is not None:
-        leases = list(filter(lambda x: in_pool(x, pool), leases))
+        if config.exists_effective("service dhcp-server shared-network-name {0}".format(pool)):
+            leases = list(filter(lambda x: in_pool(x, pool), leases))
+        else:
+            print("Pool {0} does not exist.".format(pool))
+            sys.exit(0)
 
-    leases = list(map(get_lease_data, leases))
+    # should maybe filter all state=active by lease.valid here?
+
+    # sort by last_comm time to dedupe (newest lease overrides older)
+    leases = sorted(leases, key = lambda lease: lease.last_communication)
+
+    # dedupe by converting to dict
+    leases_dict = {}
+    for lease in leases:
+        # dedupe by IP
+        leases_dict[lease.ip] = lease
+
+    # convert the lease data
+    leases = list(map(get_lease_data, leases_dict.values()))
+
+    # apply output/display sort
     if sort == 'ip':
-        leases = sorted(leases, key = lambda k: int(ipaddress.IPv6Address(k['ip'])))
+        leases = sorted(leases, key = lambda k: int(ipaddress.ip_address(k['ip'])))
     else:
         leases = sorted(leases, key = lambda k: k[sort])
 
@@ -128,7 +165,7 @@ if __name__ == '__main__':
 
     parser.add_argument("-p", "--pool", type=str, help="Show lease for specific pool")
     parser.add_argument("-S", "--sort", type=str, choices=lease_display_fields.keys(), default='ip', help="Sort by")
-    parser.add_argument("-t", "--state", type=str, choices=lease_valid_states, default="active", help="Lease state to show")
+    parser.add_argument("-t", "--state", type=str, nargs="+", choices=lease_valid_states, default="active", help="Lease state to show (can specify multiple with spaces)")
     parser.add_argument("-j", "--json", action="store_true", default=False, help="Produce JSON output")
 
     args = parser.parse_args()
@@ -139,6 +176,10 @@ if __name__ == '__main__':
         print("DHCPv6 service is not configured")
         sys.exit(0)
 
+    # if dhcp server is down, inactive leases may still be shown as active, so warn the user.
+    if os.system('systemctl -q is-active isc-dhcpv6-server.service') != 0:
+        print("WARNING: DHCPv6 server is configured but not started. Data may be stale.")
+
     if args.leases:
         leases = get_leases(lease_file, args.state, args.pool, args.sort)
 
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