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-rw-r--r--python/vyos/firewall.py259
1 files changed, 259 insertions, 0 deletions
diff --git a/python/vyos/firewall.py b/python/vyos/firewall.py
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+++ b/python/vyos/firewall.py
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+#!/usr/bin/env python3
+#
+# Copyright (C) 2021 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 re
+
+from vyos.util import cmd
+from vyos.util import dict_search_args
+
+def find_nftables_rule(table, chain, rule_matches=[]):
+ # Find rule in table/chain that matches all criteria and return the handle
+ results = cmd(f'sudo nft -a list chain {table} {chain}').split("\n")
+ for line in results:
+ if all(rule_match in line for rule_match in rule_matches):
+ handle_search = re.search('handle (\d+)', line)
+ if handle_search:
+ return handle_search[1]
+ return None
+
+def remove_nftables_rule(table, chain, handle):
+ cmd(f'sudo nft delete rule {table} {chain} handle {handle}')
+
+# Functions below used by template generation
+
+def nft_action(vyos_action):
+ if vyos_action == 'accept':
+ return 'return'
+ return vyos_action
+
+def parse_rule(rule_conf, fw_name, rule_id, ip_name):
+ output = []
+ def_suffix = '6' if ip_name == 'ip6' else ''
+
+ if 'state' in rule_conf and rule_conf['state']:
+ states = ",".join([s for s, v in rule_conf['state'].items() if v == 'enable'])
+
+ if states:
+ output.append(f'ct state {{{states}}}')
+
+ if 'connection_status' in rule_conf and rule_conf['connection_status']:
+ status = rule_conf['connection_status']
+ if status['nat'] == 'destination':
+ nat_status = '{dnat}'
+ output.append(f'ct status {nat_status}')
+ if status['nat'] == 'source':
+ nat_status = '{snat}'
+ output.append(f'ct status {nat_status}')
+
+ if 'protocol' in rule_conf and rule_conf['protocol'] != 'all':
+ proto = rule_conf['protocol']
+ operator = ''
+ if proto[0] == '!':
+ operator = '!='
+ proto = proto[1:]
+ if proto == 'tcp_udp':
+ proto = '{tcp, udp}'
+ output.append(f'meta l4proto {operator} {proto}')
+
+ for side in ['destination', 'source']:
+ if side in rule_conf:
+ prefix = side[0]
+ side_conf = rule_conf[side]
+
+ if 'address' in side_conf:
+ suffix = side_conf['address']
+ if suffix[0] == '!':
+ suffix = f'!= {suffix[1:]}'
+ output.append(f'{ip_name} {prefix}addr {suffix}')
+
+ if 'mac_address' in side_conf:
+ suffix = side_conf["mac_address"]
+ if suffix[0] == '!':
+ suffix = f'!= {suffix[1:]}'
+ output.append(f'ether {prefix}addr {suffix}')
+
+ if 'port' in side_conf:
+ proto = rule_conf['protocol']
+ port = side_conf['port'].split(',')
+
+ ports = []
+ negated_ports = []
+
+ for p in port:
+ if p[0] == '!':
+ negated_ports.append(p[1:])
+ else:
+ ports.append(p)
+
+ if proto == 'tcp_udp':
+ proto = 'th'
+
+ if ports:
+ ports_str = ','.join(ports)
+ output.append(f'{proto} {prefix}port {{{ports_str}}}')
+
+ if negated_ports:
+ negated_ports_str = ','.join(negated_ports)
+ output.append(f'{proto} {prefix}port != {{{negated_ports_str}}}')
+
+ if 'group' in side_conf:
+ group = side_conf['group']
+ if 'address_group' in group:
+ group_name = group['address_group']
+ operator = ''
+ if group_name[0] == '!':
+ operator = '!='
+ group_name = group_name[1:]
+ output.append(f'{ip_name} {prefix}addr {operator} $A{def_suffix}_{group_name}')
+ elif 'network_group' in group:
+ group_name = group['network_group']
+ operator = ''
+ if group_name[0] == '!':
+ operator = '!='
+ group_name = group_name[1:]
+ output.append(f'{ip_name} {prefix}addr {operator} $N{def_suffix}_{group_name}')
+ if 'mac_group' in group:
+ group_name = group['mac_group']
+ operator = ''
+ if group_name[0] == '!':
+ operator = '!='
+ group_name = group_name[1:]
+ output.append(f'ether {prefix}addr {operator} $M_{group_name}')
+ if 'port_group' in group:
+ proto = rule_conf['protocol']
+ group_name = group['port_group']
+
+ if proto == 'tcp_udp':
+ proto = 'th'
+
+ operator = ''
+ if group_name[0] == '!':
+ operator = '!='
+ group_name = group_name[1:]
+
+ output.append(f'{proto} {prefix}port {operator} $P_{group_name}')
+
+ if 'log' in rule_conf and rule_conf['log'] == 'enable':
+ action = rule_conf['action'] if 'action' in rule_conf else 'accept'
+ output.append(f'log prefix "[{fw_name[:19]}-{rule_id}-{action[:1].upper()}] "')
+
+ if 'hop_limit' in rule_conf:
+ operators = {'eq': '==', 'gt': '>', 'lt': '<'}
+ for op, operator in operators.items():
+ if op in rule_conf['hop_limit']:
+ value = rule_conf['hop_limit'][op]
+ output.append(f'ip6 hoplimit {operator} {value}')
+
+ for icmp in ['icmp', 'icmpv6']:
+ if icmp in rule_conf:
+ if 'type_name' in rule_conf[icmp]:
+ output.append(icmp + ' type ' + rule_conf[icmp]['type_name'])
+ else:
+ if 'code' in rule_conf[icmp]:
+ output.append(icmp + ' code ' + rule_conf[icmp]['code'])
+ if 'type' in rule_conf[icmp]:
+ output.append(icmp + ' type ' + rule_conf[icmp]['type'])
+
+ if 'ipsec' in rule_conf:
+ if 'match_ipsec' in rule_conf['ipsec']:
+ output.append('meta ipsec == 1')
+ if 'match_non_ipsec' in rule_conf['ipsec']:
+ output.append('meta ipsec == 0')
+
+ if 'fragment' in rule_conf:
+ # Checking for fragmentation after priority -400 is not possible,
+ # so we use a priority -450 hook to set a mark
+ if 'match_frag' in rule_conf['fragment']:
+ output.append('meta mark 0xffff1')
+ if 'match_non_frag' in rule_conf['fragment']:
+ output.append('meta mark != 0xffff1')
+
+ if 'limit' in rule_conf:
+ if 'rate' in rule_conf['limit']:
+ output.append(f'limit rate {rule_conf["limit"]["rate"]}')
+ if 'burst' in rule_conf['limit']:
+ output.append(f'burst {rule_conf["limit"]["burst"]} packets')
+
+ if 'recent' in rule_conf:
+ count = rule_conf['recent']['count']
+ time = rule_conf['recent']['time']
+ output.append(f'add @RECENT{def_suffix}_{fw_name}_{rule_id} {{ {ip_name} saddr limit rate over {count}/{time} burst {count} packets }}')
+
+ if 'time' in rule_conf:
+ output.append(parse_time(rule_conf['time']))
+
+ tcp_flags = dict_search_args(rule_conf, 'tcp', 'flags')
+ if tcp_flags:
+ output.append(parse_tcp_flags(tcp_flags))
+
+ output.append('counter')
+
+ if 'set' in rule_conf:
+ output.append(parse_policy_set(rule_conf['set'], def_suffix))
+
+ if 'action' in rule_conf:
+ output.append(nft_action(rule_conf['action']))
+ else:
+ output.append('return')
+
+ output.append(f'comment "{fw_name}-{rule_id}"')
+ return " ".join(output)
+
+def parse_tcp_flags(flags):
+ include = [flag for flag in flags if flag != 'not']
+ exclude = list(flags['not']) if 'not' in flags else []
+ return f'tcp flags & ({"|".join(include + exclude)}) == {"|".join(include) if include else "0x0"}'
+
+def parse_time(time):
+ out = []
+ if 'startdate' in time:
+ start = time['startdate']
+ if 'T' not in start and 'starttime' in time:
+ start += f' {time["starttime"]}'
+ out.append(f'time >= "{start}"')
+ if 'starttime' in time and 'startdate' not in time:
+ out.append(f'hour >= "{time["starttime"]}"')
+ if 'stopdate' in time:
+ stop = time['stopdate']
+ if 'T' not in stop and 'stoptime' in time:
+ stop += f' {time["stoptime"]}'
+ out.append(f'time < "{stop}"')
+ if 'stoptime' in time and 'stopdate' not in time:
+ out.append(f'hour < "{time["stoptime"]}"')
+ if 'weekdays' in time:
+ days = time['weekdays'].split(",")
+ out_days = [f'"{day}"' for day in days if day[0] != '!']
+ out.append(f'day {{{",".join(out_days)}}}')
+ return " ".join(out)
+
+def parse_policy_set(set_conf, def_suffix):
+ out = []
+ if 'dscp' in set_conf:
+ dscp = set_conf['dscp']
+ out.append(f'ip{def_suffix} dscp set {dscp}')
+ if 'mark' in set_conf:
+ mark = set_conf['mark']
+ out.append(f'meta mark set {mark}')
+ if 'table' in set_conf:
+ table = set_conf['table']
+ if table == 'main':
+ table = '254'
+ mark = 0x7FFFFFFF - int(table)
+ out.append(f'meta mark set {mark}')
+ if 'tcp_mss' in set_conf:
+ mss = set_conf['tcp_mss']
+ out.append(f'tcp option maxseg size set {mss}')
+ return " ".join(out)
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-12 21:38:53 +0000