T5474: establish common file name pattern for XML conf mode commands

We will use _ as CLI level divider. The XML definition filename and also
the Python helper should match the CLI node.

Example:
set interfaces ethernet -> interfaces_ethernet.xml.in
set interfaces bond -> interfaces_bond.xml.in
set service dhcp-server -> service_dhcp-server-xml.in

(cherry picked from commit 4ef110fd2c501b718344c72d495ad7e16d2bd465)

1 files changed, 195 insertions, 0 deletions

diff --git a/src/conf_mode/service_dhcpv6-server.py b/src/conf_mode/service_dhcpv6-server.py
new file mode 100755
index 000000000..427001609
--- /dev/null
+++ b/src/conf_mode/service_dhcpv6-server.py
@@ -0,0 +1,195 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2018-2022 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/>.
+
+import os
+
+from ipaddress import ip_address
+from ipaddress import ip_network
+from sys import exit
+
+from vyos.config import Config
+from vyos.template import render
+from vyos.template import is_ipv6
+from vyos.utils.process import call
+from vyos.utils.dict import dict_search
+from vyos.utils.network import is_subnet_connected
+from vyos import ConfigError
+from vyos import airbag
+airbag.enable()
+
+config_file = '/run/dhcp-server/dhcpdv6.conf'
+
+def get_config(config=None):
+    if config:
+        conf = config
+    else:
+        conf = Config()
+    base = ['service', 'dhcpv6-server']
+    if not conf.exists(base):
+        return None
+
+    dhcpv6 = conf.get_config_dict(base, key_mangling=('-', '_'),
+                                  get_first_key=True,
+                                  no_tag_node_value_mangle=True)
+    return dhcpv6
+
+def verify(dhcpv6):
+    # bail out early - looks like removal from running config
+    if not dhcpv6 or 'disable' in dhcpv6:
+        return None
+
+    # If DHCP is enabled we need one share-network
+    if 'shared_network_name' not in dhcpv6:
+        raise ConfigError('No DHCPv6 shared networks configured. At least '\
+                          'one DHCPv6 shared network must be configured.')
+
+    # Inspect shared-network/subnet
+    subnets = []
+    listen_ok = False
+    for network, network_config in dhcpv6['shared_network_name'].items():
+        # A shared-network requires a subnet definition
+        if 'subnet' not in network_config:
+            raise ConfigError(f'No DHCPv6 lease subnets configured for "{network}". '\
+                              'At least one lease subnet must be configured for '\
+                              'each shared network!')
+
+        for subnet, subnet_config in network_config['subnet'].items():
+            if 'address_range' in subnet_config:
+                if 'start' in subnet_config['address_range']:
+                    range6_start = []
+                    range6_stop = []
+                    for start, start_config in subnet_config['address_range']['start'].items():
+                        if 'stop' not in start_config:
+                            raise ConfigError(f'address-range stop address for start "{start}" is not defined!')
+                        stop = start_config['stop']
+
+                        # Start address must be inside network
+                        if not ip_address(start) in ip_network(subnet):
+                            raise ConfigError(f'address-range start address "{start}" is not in subnet "{subnet}"!')
+
+                        # Stop address must be inside network
+                        if not ip_address(stop) in ip_network(subnet):
+                             raise ConfigError(f'address-range stop address "{stop}" is not in subnet "{subnet}"!')
+
+                        # Stop address must be greater or equal to start address
+                        if not ip_address(stop) >= ip_address(start):
+                            raise ConfigError(f'address-range stop address "{stop}" must be greater then or equal ' \
+                                              f'to the range start address "{start}"!')
+
+                        # DHCPv6 range start address must be unique - two ranges can't
+                        # start with the same address - makes no sense
+                        if start in range6_start:
+                            raise ConfigError(f'Conflicting DHCPv6 lease range: '\
+                                              f'Pool start address "{start}" defined multipe times!')
+                        range6_start.append(start)
+
+                        # DHCPv6 range stop address must be unique - two ranges can't
+                        # end with the same address - makes no sense
+                        if stop in range6_stop:
+                            raise ConfigError(f'Conflicting DHCPv6 lease range: '\
+                                              f'Pool stop address "{stop}" defined multipe times!')
+                        range6_stop.append(stop)
+
+                if 'prefix' in subnet_config:
+                    for prefix in subnet_config['prefix']:
+                        if ip_network(prefix) not in ip_network(subnet):
+                            raise ConfigError(f'address-range prefix "{prefix}" is not in subnet "{subnet}""')
+
+            # Prefix delegation sanity checks
+            if 'prefix_delegation' in subnet_config:
+                if 'start' not in subnet_config['prefix_delegation']:
+                    raise ConfigError('prefix-delegation start address not defined!')
+
+                for prefix, prefix_config in subnet_config['prefix_delegation']['start'].items():
+                    if 'stop' not in prefix_config:
+                        raise ConfigError(f'Stop address of delegated IPv6 prefix range "{prefix}" '\
+                                          f'must be configured')
+
+                    if 'prefix_length' not in prefix_config:
+                        raise ConfigError('Length of delegated IPv6 prefix must be configured')
+
+            # Static mappings don't require anything (but check if IP is in subnet if it's set)
+            if 'static_mapping' in subnet_config:
+                for mapping, mapping_config in subnet_config['static_mapping'].items():
+                    if 'ipv6_address' in mapping_config:
+                        # Static address must be in subnet
+                        if ip_address(mapping_config['ipv6_address']) not in ip_network(subnet):
+                            raise ConfigError(f'static-mapping address for mapping "{mapping}" is not in subnet "{subnet}"!')
+
+            if 'vendor_option' in subnet_config:
+                if len(dict_search('vendor_option.cisco.tftp_server', subnet_config)) > 2:
+                    raise ConfigError(f'No more then two Cisco tftp-servers should be defined for subnet "{subnet}"!')
+
+            # Subnets must be unique
+            if subnet in subnets:
+                raise ConfigError(f'DHCPv6 subnets must be unique! Subnet {subnet} defined multiple times!')
+            subnets.append(subnet)
+
+        # DHCPv6 requires at least one configured address range or one static mapping
+        # (FIXME: is not actually checked right now?)
+
+        # There must be one subnet connected to a listen interface if network is not disabled.
+        if 'disable' not in network_config:
+            if is_subnet_connected(subnet):
+                listen_ok = True
+
+            # DHCPv6 subnet must not overlap. ISC DHCP also complains about overlapping
+            # subnets: "Warning: subnet 2001:db8::/32 overlaps subnet 2001:db8:1::/32"
+            net = ip_network(subnet)
+            for n in subnets:
+                net2 = ip_network(n)
+                if (net != net2):
+                    if net.overlaps(net2):
+                        raise ConfigError('DHCPv6 conflicting subnet ranges: {0} overlaps {1}'.format(net, net2))
+
+    if not listen_ok:
+        raise ConfigError('None of the DHCPv6 subnets are connected to a subnet6 on '\
+                          'this machine. At least one subnet6 must be connected such that '\
+                          'DHCPv6 listens on an interface!')
+
+
+    return None
+
+def generate(dhcpv6):
+    # bail out early - looks like removal from running config
+    if not dhcpv6 or 'disable' in dhcpv6:
+        return None
+
+    render(config_file, 'dhcp-server/dhcpdv6.conf.j2', dhcpv6)
+    return None
+
+def apply(dhcpv6):
+    # bail out early - looks like removal from running config
+    service_name = 'isc-dhcp-server6.service'
+    if not dhcpv6 or 'disable' in dhcpv6:
+        # DHCP server is removed in the commit
+        call(f'systemctl stop {service_name}')
+        if os.path.exists(config_file):
+            os.unlink(config_file)
+        return None
+
+    call(f'systemctl restart {service_name}')
+    return None
+
+if __name__ == '__main__':
+    try:
+        c = get_config()
+        verify(c)
+        generate(c)
+        apply(c)
+    except ConfigError as e:
+        print(e)
+        exit(1)