1 files changed, 264 insertions, 0 deletions
diff --git a/src/op_mode/show_dhcp.py b/src/op_mode/show_dhcp.py
new file mode 100755
index 000000000..ff1e3cc56
--- /dev/null
+++ b/src/op_mode/show_dhcp.py
@@ -0,0 +1,264 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2018-2020 VyOS maintainers and contributors
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 or later as
+# published by the Free Software Foundation.
+#
+# 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, see <http://www.gnu.org/licenses/>.
+#
+# TODO: merge with show_dhcpv6.py
+
+from json import dumps
+from argparse import ArgumentParser
+from ipaddress import ip_address
+from tabulate import tabulate
+from sys import exit
+from collections import OrderedDict
+from datetime import datetime
+
+from isc_dhcp_leases import Lease, IscDhcpLeases
+
+from vyos.config import Config
+from vyos.util import call
+
+
+lease_file = "/config/dhcpd.leases"
+pool_key = "shared-networkname"
+
+lease_display_fields = OrderedDict()
+lease_display_fields['ip'] = 'IP address'
+lease_display_fields['hardware_address'] = 'Hardware address'
+lease_display_fields['state'] = 'State'
+lease_display_fields['start'] = 'Lease start'
+lease_display_fields['end'] = 'Lease expiration'
+lease_display_fields['remaining'] = 'Remaining'
+lease_display_fields['pool'] = 'Pool'
+lease_display_fields['hostname'] = 'Hostname'
+
+lease_valid_states = ['all', 'active', 'free', 'expired', 'released', 'abandoned', 'reset', 'backup']
+
+def in_pool(lease, pool):
+    if pool_key in lease.sets:
+        if lease.sets[pool_key] == pool:
+            return True
+
+    return False
+
+def utc_to_local(utc_dt):
+    return datetime.fromtimestamp((utc_dt - datetime(1970,1,1)).total_seconds())
+
+def get_lease_data(lease):
+    data = {}
+
+    # isc-dhcp lease times are in UTC so we need to convert them to local time to display
+    try:
+        data["start"] = utc_to_local(lease.start).strftime("%Y/%m/%d %H:%M:%S")
+    except:
+        data["start"] = ""
+
+    try:
+        data["end"] = utc_to_local(lease.end).strftime("%Y/%m/%d %H:%M:%S")
+    except:
+        data["end"] = ""
+
+    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"] = ""
+
+    # currently not used but might come in handy
+    # todo: parse into datetime string
+    for prop in ['tstp', 'tsfp', 'atsfp', 'cltt']:
+        if prop in lease.data:
+            data[prop] = lease.data[prop]
+        else:
+            data[prop] = ''
+
+    data["hardware_address"] = lease.ethernet
+    data["hostname"] = lease.hostname
+
+    data["state"] = lease.binding_state
+    data["ip"] = lease.ip
+
+    try:
+        data["pool"] = lease.sets[pool_key]
+    except:
+        data["pool"] = ""
+
+    return data
+
+def get_leases(config, leases, state, pool=None, sort='ip'):
+    # get leases from file
+    leases = IscDhcpLeases(lease_file).get()
+
+    # filter leases by state
+    if 'all' not in state:
+        leases = list(filter(lambda x: x.binding_state in state, leases))
+
+    # filter leases by pool name
+    if pool is not None:
+        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))
+            exit(0)
+
+    # should maybe filter all state=active by lease.valid here?
+
+    # sort by start time to dedupe (newest lease overrides older)
+    leases = sorted(leases, key = lambda lease: lease.start)
+
+    # 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 lease: int(ip_address(lease['ip'])))
+    else:
+        leases = sorted(leases, key = lambda lease: lease[sort])
+
+    return leases
+
+def show_leases(leases):
+    lease_list = []
+    for l in leases:
+        lease_list_params = []
+        for k in lease_display_fields.keys():
+            lease_list_params.append(l[k])
+        lease_list.append(lease_list_params)
+
+    output = tabulate(lease_list, lease_display_fields.values())
+
+    print(output)
+
+def get_pool_size(config, pool):
+    size = 0
+    subnets = config.list_effective_nodes("service dhcp-server shared-network-name {0} subnet".format(pool))
+    for s in subnets:
+        ranges = config.list_effective_nodes("service dhcp-server shared-network-name {0} subnet {1} range".format(pool, s))
+        for r in ranges:
+            start = config.return_effective_value("service dhcp-server shared-network-name {0} subnet {1} range {2} start".format(pool, s, r))
+            stop = config.return_effective_value("service dhcp-server shared-network-name {0} subnet {1} range {2} stop".format(pool, s, r))
+
+            # Add +1 because both range boundaries are inclusive
+            size += int(ip_address(stop)) - int(ip_address(start)) + 1
+
+    return size
+
+def show_pool_stats(stats):
+    headers = ["Pool", "Size", "Leases", "Available", "Usage"]
+    output = tabulate(stats, headers)
+
+    print(output)
+
+if __name__ == '__main__':
+    parser = ArgumentParser()
+
+    group = parser.add_mutually_exclusive_group()
+    group.add_argument("-l", "--leases", action="store_true", help="Show DHCP leases")
+    group.add_argument("-s", "--statistics", action="store_true", help="Show DHCP statistics")
+    group.add_argument("--allowed", type=str, choices=["pool", "sort", "state"], help="Show allowed values for argument")
+
+    parser.add_argument("-p", "--pool", type=str, help="Show lease for specific pool")
+    parser.add_argument("-S", "--sort", type=str, default='ip', help="Sort by")
+    parser.add_argument("-t", "--state", type=str, nargs="+", 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()
+
+    conf = Config()
+
+    if args.allowed == 'pool':
+        if conf.exists_effective('service dhcp-server'):
+            print(' '.join(conf.list_effective_nodes("service dhcp-server shared-network-name")))
+        exit(0)
+    elif args.allowed == 'sort':
+        print(' '.join(lease_display_fields.keys()))
+        exit(0)
+    elif args.allowed == 'state':
+        print(' '.join(lease_valid_states))
+        exit(0)
+    elif args.allowed:
+        parser.print_help()
+        exit(1)
+
+    if args.sort not in lease_display_fields.keys():
+        print(f'Invalid sort key, choose from: {list(lease_display_fields.keys())}')
+        exit(0)
+
+    if not set(args.state) < set(lease_valid_states):
+            print(f'Invalid lease state, choose from: {lease_valid_states}')
+            exit(0)
+
+    # Do nothing if service is not configured
+    if not conf.exists_effective('service dhcp-server'):
+        print("DHCP service is not configured.")
+        exit(0)
+
+    # if dhcp server is down, inactive leases may still be shown as active, so warn the user.
+    if call('systemctl -q is-active isc-dhcp-server.service') != 0:
+        print("WARNING: DHCP server is configured but not started. Data may be stale.")
+
+    if args.leases:
+        leases = get_leases(conf, lease_file, args.state, args.pool, args.sort)
+
+        if args.json:
+            print(dumps(leases, indent=4))
+        else:
+            show_leases(leases)
+
+    elif args.statistics:
+        pools = []
+
+        # Get relevant pools
+        if args.pool:
+            pools = [args.pool]
+        else:
+            pools = conf.list_effective_nodes("service dhcp-server shared-network-name")
+
+        # Get pool usage stats
+        stats = []
+        for p in pools:
+            size = get_pool_size(conf, p)
+            leases = len(get_leases(conf, lease_file, state='active', pool=p))
+
+            use_percentage = round(leases / size * 100) if size != 0 else 0
+
+            if args.json:
+                pool_stats = {"pool": p, "size": size, "leases": leases,
+                              "available": (size - leases), "percentage": use_percentage}
+            else:
+                # For tabulate
+                pool_stats = [p, size, leases, size - leases, "{0}%".format(use_percentage)]
+            stats.append(pool_stats)
+
+        # Print stats
+        if args.json:
+            print(dumps(stats, indent=4))
+        else:
+            show_pool_stats(stats)
+
+    else:
+        parser.print_help()
+        exit(1)