102 lines
2.6 KiB
Python
Executable file
102 lines
2.6 KiB
Python
Executable file
#!/usr/bin/env python3
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from nftables import Nftables
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from os import path
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import sys
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import json
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NFT = Nftables()
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NAME = path.basename(__file__)
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TABLE_NAME = "inet filter"
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def error(message, code):
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print("%s: %s" % (NAME, message), file = sys.stderr)
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exit(code)
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def error_no_arg(arg_name):
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error("no %s provided" % (arg_name), 1)
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def error_invalid_arg(arg_name, value):
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error('invalid %s "%s"' % (arg_name, value), 2)
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def usage():
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print("""
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{name}: dumb Python wrapper for nftables o_O
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usage:
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{name} list - show currently allowed ports
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{name} help - show this :)
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{name} allow|deny <protocol> <port number> - add or remove a port from the filtered sets
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""".format(name = NAME).strip())
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def get_nft_set_for(protocol):
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return json.loads(NFT.cmd("list set %s allowed_%s" % (TABLE_NAME, protocol))[1])["nftables"][1]["set"]
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def show_ports():
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NFT.set_json_output(True)
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tcp_ports = get_nft_set_for("tcp")
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udp_ports = get_nft_set_for("udp")
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if "elem" in tcp_ports:
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print("Allowed TCP ports : %s" % (tcp_ports["elem"]))
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if "elem" in udp_ports:
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print("Allowed UDP ports: %s" % (udp_ports["elem"]))
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def allowed_ports(operation, protocol, port):
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if operation != "add" and operation != "delete":
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raise ValueError("not a valid nftables operation")
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if protocol != "tcp" and protocol != "udp":
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raise ValueError("not a valid protocol")
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if port < 0 or port > 65535:
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raise ValueError("not a valid port number")
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NFT.cmd("%s element %s allowed_%s { %d }" % (operation, TABLE_NAME, protocol, port))
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def manage_ports(action, args):
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match action:
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case "allow":
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operation = "add"
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case "deny":
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operation = "delete"
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case _:
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raise ValueError("invalid action")
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try:
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protocol = args.pop(0)
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except IndexError:
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error_no_arg("protocol")
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try:
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port = args.pop(0)
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except IndexError:
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error_no_arg("port")
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try:
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port = int(port)
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except ValueError:
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error_invalid_arg("port", port)
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try:
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allowed_ports(operation, protocol, port)
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except ValueError as e:
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error(e, 3)
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if __name__ == "__main__":
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sys.argv.pop(0)
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try:
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action = sys.argv.pop(0)
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except IndexError:
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error_no_arg("action")
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match action:
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case "help":
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usage()
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case "allow" | "deny":
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manage_ports(action, sys.argv)
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case "list":
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show_ports()
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case _:
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error_invalid_arg("action", action)
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