dhcp: T3316: Migrate dhcp/dhcpv6 server to Kea

4 files changed, 452 insertions, 0 deletions

diff --git a/python/vyos/kea.py b/python/vyos/kea.py
new file mode 100644
index 000000000..0ee6871e7
--- /dev/null
+++ b/python/vyos/kea.py
@@ -0,0 +1,310 @@
+# Copyright 2023 VyOS maintainers and contributors <maintainers@vyos.io>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library 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
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+import json
+import os
+import socket
+
+from datetime import datetime
+
+from vyos.template import is_ipv6
+from vyos.template import isc_static_route
+from vyos.template import netmask_from_cidr
+from vyos.utils.dict import dict_search_args
+from vyos.utils.file import read_file
+
+kea4_options = {
+    'name_server': 'domain-name-servers',
+    'domain_name': 'domain-name',
+    'domain_search': 'domain-search',
+    'ntp_server': 'ntp-servers',
+    'pop_server': 'pop-server',
+    'smtp_server': 'smtp-server',
+    'time_server': 'time-servers',
+    'wins_server': 'netbios-name-servers',
+    'default_router': 'routers',
+    'server_identifier': 'dhcp-server-identifier',
+    'tftp_server_name': 'tftp-server-name',
+    'bootfile_size': 'boot-size',
+    'time_offset': 'time-offset',
+    'wpad_url': 'wpad-url',
+    'ipv6_only_preferred': 'v6-only-preferred'
+}
+
+kea6_options = {
+    'info_refresh_time': 'information-refresh-time',
+    'name_server': 'dns-servers',
+    'domain_search': 'domain-search',
+    'nis_domain': 'nis-domain-name',
+    'nis_server': 'nis-servers',
+    'nisplus_domain': 'nisp-domain-name',
+    'nisplus_server': 'nisp-servers',
+    'sntp_server': 'sntp-servers'
+}
+
+def kea_parse_options(config):
+    options = []
+
+    for node, option_name in kea4_options.items():
+        if node not in config:
+            continue
+
+        value = ", ".join(config[node]) if isinstance(config[node], list) else config[node]
+        options.append({'name': option_name, 'data': value})
+
+    if 'client_prefix_length' in config:
+        options.append({'name': 'subnet-mask', 'data': netmask_from_cidr('0.0.0.0/' + config['client_prefix_length'])})
+
+    if 'ip_forwarding' in config:
+        options.append({'name': 'ip-forwarding', 'data': "true"})
+
+    if 'static_route' in config:
+        default_route = ''
+
+        if 'default_router' in config:
+            default_route = isc_static_route('0.0.0.0/0', config['default_router'])
+
+        routes = [isc_static_route(route, route_options['next_hop']) for route, route_options in config['static_route'].items()]
+
+        options.append({'name': 'rfc3442-static-route', 'data': ", ".join(routes if not default_route else routes + [default_route])})
+        options.append({'name': 'windows-static-route', 'data': ", ".join(routes)})
+
+    return options
+
+def kea_parse_subnet(subnet, config):
+    out = {'subnet': subnet}
+    options = kea_parse_options(config)
+
+    if 'bootfile_name' in config:
+        out['boot-file-name'] = config['bootfile_name']
+
+    if 'bootfile_server' in config:
+        out['next-server'] = config['bootfile_server']
+
+    if 'lease' in config:
+        out['valid-lifetime'] = int(config['lease'])
+        out['max-valid-lifetime'] = int(config['lease'])
+
+    if 'range' in config:
+        pools = []
+        for num, range_config in config['range'].items():
+            start, stop = range_config['start'], range_config['stop']
+            pools.append({'pool': f'{start} - {stop}'})
+        out['pools'] = pools
+
+    if 'static_mapping' in config:
+        reservations = []
+        for host, host_config in config['static_mapping'].items():
+            if 'disable' in host_config:
+                continue
+
+            reservations.append({
+                'hw-address': host_config['mac_address'],
+                'ip-address': host_config['ip_address']
+            })
+        out['reservations'] = reservations
+
+    unifi_controller = dict_search_args(config, 'vendor_option', 'ubiquiti', 'unifi_controller')
+    if unifi_controller:
+        options.append({
+            'name': 'unifi-controller',
+            'data': unifi_controller,
+            'space': 'ubnt'
+        })
+
+    if options:
+        out['option-data'] = options
+
+    return out
+
+def kea6_parse_options(config):
+    options = []
+
+    if 'common_options' in config:
+        common_opt = config['common_options']
+
+        for node, option_name in kea6_options.items():
+            if node not in common_opt:
+                continue
+
+            value = ", ".join(common_opt[node]) if isinstance(common_opt[node], list) else common_opt[node]
+            options.append({'name': option_name, 'data': value})
+
+    for node, option_name in kea6_options.items():
+        if node not in config:
+            continue
+
+        value = ", ".join(config[node]) if isinstance(config[node], list) else config[node]
+        options.append({'name': option_name, 'data': value})
+
+    if 'sip_server' in config:
+        sip_servers = config['sip_server']
+
+        addrs = []
+        hosts = []
+
+        for server in sip_servers:
+            if is_ipv6(server):
+                addrs.append(server)
+            else:
+                hosts.append(server)
+
+        if addrs:
+            options.append({'name': 'sip-server-addr', 'data': ", ".join(addrs)})
+        
+        if hosts:
+            options.append({'name': 'sip-server-dns', 'data': ", ".join(hosts)})
+
+    cisco_tftp = dict_search_args(config, 'vendor_option', 'cisco', 'tftp-server')
+    if cisco_tftp:
+        options.append({'name': 'tftp-servers', 'code': 2, 'space': 'cisco', 'data': cisco_tftp})
+
+    return options
+
+def kea6_parse_subnet(subnet, config):
+    out = {'subnet': subnet}
+    options = kea6_parse_options(config)
+
+    if 'address_range' in config:
+        addr_range = config['address_range']
+        pools = []
+
+        if 'prefix' in addr_range:
+            for prefix in addr_range['prefix']:
+                pools.append({'pool': prefix})
+
+        if 'start' in addr_range:
+            for start, range_conf in addr_range['start'].items():
+                stop = range_conf['stop']
+                pools.append({'pool': f'{start} - {stop}'})
+
+        out['pools'] = pools
+
+    if 'prefix_delegation' in config:
+        pd_pools = []
+
+        if 'prefix' in config['prefix_delegation']:
+            for prefix, pd_conf in config['prefix_delegation']['prefix'].items():
+                pd_pools.append({
+                    'prefix': prefix,
+                    'prefix-len': int(pd_conf['prefix_length']),
+                    'delegated-len': int(pd_conf['delegated_length'])
+                })
+
+        out['pd-pools'] = pd_pools
+
+    if 'lease_time' in config:
+        if 'default' in config['lease_time']:
+            out['valid-lifetime'] = int(config['lease_time']['default'])
+        if 'maximum' in config['lease_time']:
+            out['max-valid-lifetime'] = int(config['lease_time']['maximum'])
+        if 'minimum' in config['lease_time']:
+            out['min-valid-lifetime'] = int(config['lease_time']['minimum'])
+
+    if 'static_mapping' in config:
+        reservations = []
+        for host, host_config in config['static_mapping'].items():
+            if 'disable' in host_config:
+                continue
+
+            reservation = {}
+
+            if 'identifier' in host_config:
+                reservation['duid'] = host_config['identifier']
+
+            if 'ipv6_address' in host_config:
+                reservation['ip-addresses'] = [ host_config['ipv6_address'] ]
+
+            if 'ipv6_prefix' in host_config:
+                reservation['prefixes'] = [ host_config['ipv6_prefix'] ]
+
+            reservations.append(reservation)
+
+        out['reservations'] = reservations
+
+    if options:
+        out['option-data'] = options
+
+    return out
+
+def kea_parse_leases(lease_path):
+    contents = read_file(lease_path)
+    lines = contents.split("\n")
+    output = []
+
+    if len(lines) < 2:
+        return output
+
+    headers = lines[0].split(",")
+
+    for line in lines[1:]:
+        line_out = dict(zip(headers, line.split(",")))
+
+        lifetime = int(line_out['valid_lifetime'])
+        expiry = int(line_out['expire'])
+
+        line_out['start_timestamp'] = datetime.utcfromtimestamp(expiry - lifetime)
+        line_out['expire_timestamp'] = datetime.utcfromtimestamp(expiry) if expiry else None
+
+        output.append(line_out)
+
+    return output
+
+def _ctrl_socket_command(path, command, args=None):
+    if not os.path.exists(path):
+        return None
+
+    with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as sock:
+        sock.connect(path)
+
+        payload = {'command': command}
+        if args:
+            payload['arguments'] = args
+
+        sock.send(bytes(json.dumps(payload), 'utf-8'))
+        result = b''
+        while True:
+            data = sock.recv(4096)
+            result += data
+            if len(data) < 4096:
+                break
+
+        return json.loads(result.decode('utf-8'))
+
+def kea_get_active_config(inet):
+    ctrl_socket = f'/run/kea/dhcp{inet}-ctrl-socket'
+
+    config = _ctrl_socket_command(ctrl_socket, 'config-get')
+    
+    if not config or 'result' not in config or config['result'] != 0:
+        return None
+
+    return config
+
+def kea_get_pool_from_subnet_id(config, inet, subnet_id):
+    shared_networks = dict_search_args(config, 'arguments', f'Dhcp{inet}', 'shared-networks')
+
+    if not shared_networks:
+        return None
+
+    for network in shared_networks:
+        if f'subnet{inet}' not in network:
+            continue
+
+        for subnet in network[f'subnet{inet}']:
+            if 'id' in subnet and int(subnet['id']) == int(subnet_id):
+                return network['name']
+
+    return None
diff --git a/python/vyos/template.py b/python/vyos/template.py
index 2d4beeec2..f0a50e728 100644
--- a/python/vyos/template.py
+++ b/python/vyos/template.py
@@ -791,6 +791,106 @@ def range_to_regex(num_range):
     regex = range_to_regex(num_range)
     return f'({regex})'
 
+@register_filter('kea_failover_json')
+def kea_failover_json(config):
+    from json import dumps
+
+    source_addr = config['source_address']
+    remote_addr = config['remote']
+
+    data = {
+        'this-server-name': os.uname()[1],
+        'mode': 'hot-standby',
+        'heartbeat-delay': 10000,
+        'max-response-delay': 10000,
+        'max-ack-delay': 5000,
+        'max-unacked-clients': 0,
+        'peers': [
+        {
+            'name': os.uname()[1],
+            'url': f'http://{source_addr}:647/',
+            'role': 'standby' if config['status'] == 'secondary' else 'primary',
+            'auto-failover': True
+        },
+        {
+            'name': config['name'],
+            'url': f'http://{remote_addr}:647/',
+            'role': 'primary' if config['status'] == 'secondary' else 'standby',
+            'auto-failover': True
+        }]
+    }
+
+    if 'ca_cert_file' in config:
+        data['trust-anchor'] = config['ca_cert_file']
+
+    if 'cert_file' in config:
+        data['cert-file'] = config['cert_file']
+
+    if 'cert_key_file' in config:
+        data['key-file'] = config['cert_key_file']
+
+    return dumps(data)
+
+@register_filter('kea_shared_network_json')
+def kea_shared_network_json(shared_networks):
+    from vyos.kea import kea_parse_options
+    from vyos.kea import kea_parse_subnet
+    from json import dumps
+    out = []
+
+    for name, config in shared_networks.items():
+        if 'disable' in config:
+            continue
+
+        network = {
+            'name': name,
+            'authoritative': ('authoritative' in config),
+            'subnet4': []
+        }
+        options = kea_parse_options(config)
+
+        if 'subnet' in config:
+            for subnet, subnet_config in config['subnet'].items():
+                network['subnet4'].append(kea_parse_subnet(subnet, subnet_config))
+
+        if options:
+            network['option-data'] = options
+
+        out.append(network)
+
+    return dumps(out, indent=4)
+
+@register_filter('kea6_shared_network_json')
+def kea6_shared_network_json(shared_networks):
+    from vyos.kea import kea6_parse_options
+    from vyos.kea import kea6_parse_subnet
+    from json import dumps
+    out = []
+
+    for name, config in shared_networks.items():
+        if 'disable' in config:
+            continue
+
+        network = {
+            'name': name,
+            'subnet6': []
+        }
+        options = kea6_parse_options(config)
+
+        if 'interface' in config:
+            network['interface'] = config['interface']
+
+        if 'subnet' in config:
+            for subnet, subnet_config in config['subnet'].items():
+                network['subnet6'].append(kea6_parse_subnet(subnet, subnet_config))
+
+        if options:
+            network['option-data'] = options
+
+        out.append(network)
+
+    return dumps(out, indent=4)
+
 @register_test('vyos_defined')
 def vyos_defined(value, test_value=None, var_type=None):
     """
diff --git a/python/vyos/utils/file.py b/python/vyos/utils/file.py
index 9f27a7fb9..2af87a0ca 100644
--- a/python/vyos/utils/file.py
+++ b/python/vyos/utils/file.py
@@ -141,6 +141,14 @@ def chmod_2775(path):
     bitmask = S_ISGID | S_IRWXU | S_IRWXG | S_IROTH | S_IXOTH
     chmod(path, bitmask)
 
+def chmod_775(path):
+    """ Make file executable by all """
+    from stat import S_IRUSR, S_IWUSR, S_IXUSR, S_IRGRP, S_IWGRP, S_IXGRP, S_IROTH, S_IXOTH
+
+    bitmask = S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP | \
+              S_IROTH | S_IXOTH
+    chmod(path, bitmask)
+
 def makedir(path, user=None, group=None):
     if os.path.exists(path):
         return
diff --git a/python/vyos/utils/network.py b/python/vyos/utils/network.py
index 2a0808fca..abc3d4e5b 100644
--- a/python/vyos/utils/network.py
+++ b/python/vyos/utils/network.py
@@ -519,3 +519,37 @@ def get_vxlan_vni_filter(interface: str) -> list:
             os_configured_vnis.append(str(vniStart))
 
     return os_configured_vnis
+
+# Calculate prefix length of an IPv6 range, where possible
+# Python-ified from source: https://gitlab.isc.org/isc-projects/dhcp/-/blob/master/keama/confparse.c#L4591
+def ipv6_prefix_length(low, high):
+    import socket
+
+    bytemasks = [0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff]
+
+    try:
+        lo = bytearray(socket.inet_pton(socket.AF_INET6, low))
+        hi = bytearray(socket.inet_pton(socket.AF_INET6, high))
+    except:
+        return None
+
+    xor = bytearray(a ^ b for a, b in zip(lo, hi))
+        
+    plen = 0
+    while plen < 128 and xor[plen // 8] == 0:
+        plen += 8
+        
+    if plen == 128:
+        return plen
+    
+    for i in range((plen // 8) + 1, 16):
+        if xor[i] != 0:
+            return None
+    
+    for i in range(8):
+        msk = ~xor[plen // 8] & 0xff
+        
+        if msk == bytemasks[i]:
+            return plen + i + 1
+
+    return None