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#!/usr/bin/env python3
#
# Copyright (C) 2023-2024 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/>.
# pylint: disable=empty-docstring,missing-module-docstring
import csv
import os
import re
from ipaddress import IPv6Network, IPv6Address
from json import dumps as json_write
from vyos import ConfigError
from vyos import airbag
from vyos.config import Config
from vyos.configdict import is_node_changed
from vyos.utils.dict import dict_search
from vyos.utils.file import write_file
from vyos.utils.kernel import check_kmod
from vyos.utils.process import cmd
from vyos.utils.process import run
airbag.enable()
INSTANCE_REGEX = re.compile(r"instance-(\d+)")
JOOL_CONFIG_DIR = "/run/jool"
def get_config(config: Config | None = None) -> None:
if config is None:
config = Config()
base = ["nat64"]
nat64 = config.get_config_dict(base, key_mangling=("-", "_"), get_first_key=True)
return nat64
def verify(nat64) -> None:
check_kmod(["jool"])
base_src = ["nat64", "source", "rule"]
# Load in existing instances so we can destroy any unknown
lines = cmd("jool instance display --csv").splitlines()
for _, instance, _ in csv.reader(lines):
match = INSTANCE_REGEX.fullmatch(instance)
if not match:
# FIXME: Instances that don't match should be ignored but WARN'ed to the user
continue
num = match.group(1)
rules = nat64.setdefault("source", {}).setdefault("rule", {})
# Mark it for deletion
if num not in rules:
rules[num] = {"deleted": True}
continue
# If the user changes the mode, recreate the instance else Jool fails with:
# Jool error: Sorry; you can't change an instance's framework for now.
if is_node_changed(config, base_src + [f"instance-{num}", "mode"]):
rules[num]["recreate"] = True
# If the user changes the pool6, recreate the instance else Jool fails with:
# Jool error: Sorry; you can't change a NAT64 instance's pool6 for now.
if dict_search("source.prefix", rules[num]) and is_node_changed(
config,
base_src + [num, "source", "prefix"],
):
rules[num]["recreate"] = True
if not nat64:
# nothing left to do
return
if dict_search("source.rule", nat64):
# Ensure only 1 netfilter instance per namespace
nf_rules = filter(
lambda i: "deleted" not in i and i.get('mode') == "netfilter",
nat64["source"]["rule"].values(),
)
next(nf_rules, None) # Discard the first element
if next(nf_rules, None) is not None:
raise ConfigError(
"Jool permits only 1 NAT64 netfilter instance (per network namespace)"
)
for rule, instance in nat64["source"]["rule"].items():
if "deleted" in instance:
continue
# Verify that source.prefix is set and is a /96
if not dict_search("source.prefix", instance):
raise ConfigError(f"Source NAT64 rule {rule} missing source prefix")
src_prefix = IPv6Network(instance["source"]["prefix"])
if src_prefix.prefixlen != 96:
raise ConfigError(f"Source NAT64 rule {rule} source prefix must be /96")
if (int(src_prefix[0]) & int(IPv6Address('0:0:0:0:ff00::'))) != 0:
raise ConfigError(
f'Source NAT64 rule {rule} source prefix is not RFC6052-compliant: '
'bits 64 to 71 (9th octet) must be zeroed'
)
pools = dict_search("translation.pool", instance)
if pools:
for num, pool in pools.items():
if "address" not in pool:
raise ConfigError(
f"Source NAT64 rule {rule} translation pool "
f"{num} missing address/prefix"
)
if "port" not in pool:
raise ConfigError(
f"Source NAT64 rule {rule} translation pool "
f"{num} missing port(-range)"
)
def generate(nat64) -> None:
if not nat64:
return
os.makedirs(JOOL_CONFIG_DIR, exist_ok=True)
if dict_search("source.rule", nat64):
for rule, instance in nat64["source"]["rule"].items():
if "deleted" in instance:
# Delete the unused instance file
os.unlink(os.path.join(JOOL_CONFIG_DIR, f"instance-{rule}.json"))
continue
name = f"instance-{rule}"
config = {
"instance": name,
"framework": "netfilter",
"global": {
"pool6": instance["source"]["prefix"],
"manually-enabled": "disable" not in instance,
},
# "bib": [],
}
if "description" in instance:
config["comment"] = instance["description"]
if dict_search("translation.pool", instance):
pool4 = []
# mark
mark = ''
if dict_search("match.mark", instance):
mark = instance["match"]["mark"]
for pool in instance["translation"]["pool"].values():
if "disable" in pool:
continue
protos = pool.get("protocol", {}).keys() or ("tcp", "udp", "icmp")
for proto in protos:
obj = {
"protocol": proto.upper(),
"prefix": pool["address"],
"port range": pool["port"],
}
if mark:
obj["mark"] = int(mark)
if "description" in pool:
obj["comment"] = pool["description"]
pool4.append(obj)
if pool4:
config["pool4"] = pool4
write_file(f'{JOOL_CONFIG_DIR}/{name}.json', json_write(config, indent=2))
def apply(nat64) -> None:
if not nat64:
unload_kmod(['jool'])
return
if dict_search("source.rule", nat64):
# Deletions first to avoid conflicts
for rule, instance in nat64["source"]["rule"].items():
if not any(k in instance for k in ("deleted", "recreate")):
continue
ret = run(f"jool instance remove instance-{rule}")
if ret != 0:
raise ConfigError(
f"Failed to remove nat64 source rule {rule} (jool instance instance-{rule})"
)
# Now creations
for rule, instance in nat64["source"]["rule"].items():
if "deleted" in instance:
continue
name = f"instance-{rule}"
ret = run(f"jool -i {name} file handle {JOOL_CONFIG_DIR}/{name}.json")
if ret != 0:
raise ConfigError(f"Failed to set jool instance {name}")
if __name__ == "__main__":
try:
c = get_config()
verify(c)
generate(c)
apply(c)
except ConfigError as e:
print(e)
exit(1)
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