bundlewrap/bundles/nftables/metadata.py

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from bundlewrap.exceptions import BundleError
@metadata_reactor.provides(
'nftables/rules/99-port_rules',
)
def port_rules_to_nftables(metadata):
# Using this, bundles can simply set up port based rules. This
# reactor will then take care of converting those rules to actual
# nftables rules
ruleset = set()
# Plese note we do not set any defaults for ports. Bundles are
# expected to know themselves which default to use.
for portdef, targets in metadata.get('firewall/port_rules', {}).items():
if '/' in portdef:
port, proto = portdef.split('/', 2)
if proto not in {'udp'}:
raise BundleError(f'firewall/port_rules: illegal identifier {portdef} in metadata for {node.name}')
else:
port = portdef
proto = 'tcp'
for target in targets:
if port == '*' and target == '*':
raise BundleError('firewall/port_rules: setting both port and target to * is unsupported')
comment = f'comment "port_rules {target}"'
if port != '*':
if ':' in port:
parts = port.split(':')
port_str = f'{proto} dport {{ {parts[0]}-{parts[1]} }}'
else:
port_str = f'{proto} dport {port}'
else:
port_str = f'meta l4proto {proto}'
if target in ('ipv4', 'ipv6'):
version_str = f'meta nfproto {target}'
else:
version_str = ''
if target in ('*', 'ipv4', 'ipv6'):
ruleset.add(f'inet filter input {version_str} {port_str} accept {comment}')
else:
resolved = repo.libs.tools.resolve_identifier(repo, target)
for address in resolved['ipv4']:
ruleset.add(f'inet filter input meta nfproto ipv4 {port_str} ip saddr {address} accept {comment}')
for address in resolved['ipv6']:
ruleset.add(f'inet filter input meta nfproto ipv6 {port_str} ip6 saddr {address} accept {comment}')
return {
'nftables': {
'rules': {
# order does not matter here.
'99-port_rules': sorted(ruleset),
},
},
}