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#!/usr/bin/env python3
#
# Copyright (C) 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 jmespath
import json
import sys
from sys import exit
from tabulate import tabulate
from vyos.util import cmd
from vyos.util import dict_search
import vyos.opmode
def _get_json_data(direction):
"""
Get NAT format JSON
"""
if direction == 'source':
chain = 'POSTROUTING'
if direction == 'destination':
chain = 'PREROUTING'
return cmd(f'sudo nft --json list chain ip nat {chain}')
def _get_raw_data_rules(direction):
"""Get interested rules
:returns dict
"""
data = _get_json_data(direction)
data_dict = json.loads(data)
rules = []
for rule in data_dict['nftables']:
if 'rule' in rule and 'comment' in rule['rule']:
rules.append(rule)
return rules
def _get_formatted_output_rules(data, direction):
# Add default values before loop
sport, dport, proto = 'any', 'any', 'any'
saddr, daddr = '0.0.0.0/0', '0.0.0.0/0'
data_entries = []
for rule in data:
if 'comment' in rule['rule']:
comment = rule.get('rule').get('comment')
rule_number = comment.split('-')[-1]
rule_number = rule_number.split(' ')[0]
if 'expr' in rule['rule']:
interface = rule.get('rule').get('expr')[0].get('match').get('right') \
if jmespath.search('rule.expr[*].match.left.meta', rule) else 'any'
for index, match in enumerate(jmespath.search('rule.expr[*].match', rule)):
if 'payload' in match['left']:
if 'prefix' in match['right'] or 'set' in match['right']:
# Merge dict src/dst l3_l4 parameters
my_dict = {**match['left']['payload'], **match['right']}
proto = my_dict.get('protocol').upper()
if my_dict['field'] == 'saddr':
saddr = f'{my_dict["prefix"]["addr"]}/{my_dict["prefix"]["len"]}'
elif my_dict['field'] == 'daddr':
daddr = f'{my_dict["prefix"]["addr"]}/{my_dict["prefix"]["len"]}'
elif my_dict['field'] == 'sport':
# Port range or single port
if jmespath.search('set[*].range', my_dict):
sport = my_dict['set'][0]['range']
sport = '-'.join(map(str, sport))
else:
sport = my_dict.get('set')
sport = ','.join(map(str, sport))
elif my_dict['field'] == 'dport':
# Port range or single port
if jmespath.search('set[*].range', my_dict):
dport = my_dict["set"][0]["range"]
dport = '-'.join(map(str, dport))
else:
dport = my_dict.get('set')
dport = ','.join(map(str, dport))
else:
if jmespath.search('left.payload.field', match) == 'saddr':
saddr = match.get('right')
if jmespath.search('left.payload.field', match) == 'daddr':
daddr = match.get('right')
else:
saddr = '0.0.0.0/0'
daddr = '0.0.0.0/0'
sport = 'any'
dport = 'any'
proto = 'any'
source = f'''{saddr}
sport {sport}'''
destination = f'''{daddr}
dport {dport}'''
if jmespath.search('left.payload.field', match) == 'protocol':
field_proto = match.get('right').upper()
for expr in rule.get('rule').get('expr'):
if 'snat' in expr:
translation = dict_search('snat.addr', expr)
if expr['snat'] and 'port' in expr['snat']:
if jmespath.search('snat.port.range', expr):
port = dict_search('snat.port.range', expr)
port = '-'.join(map(str, port))
else:
port = expr['snat']['port']
translation = f'''{translation}
port {port}'''
elif 'masquerade' in expr:
translation = 'masquerade'
if expr['masquerade'] and 'port' in expr['masquerade']:
if jmespath.search('masquerade.port.range', expr):
port = dict_search('masquerade.port.range', expr)
port = '-'.join(map(str, port))
else:
port = expr['masquerade']['port']
translation = f'''{translation}
port {port}'''
else:
translation = 'exclude'
# Overwrite match loop 'proto' if specified filed 'protocol' exist
if 'protocol' in jmespath.search('rule.expr[*].match.left.payload.field', rule):
proto = jmespath.search('rule.expr[0].match.right', rule).upper()
data_entries.append([rule_number, source, destination, proto, interface, translation])
interface_header = 'Out-Int' if direction == 'source' else 'In-Int'
headers = ["Rule", "Source", "Destination", "Proto", interface_header, "Translation"]
output = tabulate(data_entries, headers, numalign="left")
return output
def show_rules(raw: bool, direction: str):
nat_rules = _get_raw_data_rules(direction)
if raw:
return nat_rules
else:
return _get_formatted_output_rules(nat_rules, direction)
if __name__ == '__main__':
try:
res = vyos.opmode.run(sys.modules[__name__])
if res:
print(res)
except ValueError as e:
print(e)
sys.exit(1)
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