Initial version

.gitignore

@@ -161,4 +161,3 @@ cython_debug/
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
 #.idea/
-

LICENSE

@@ -0,0 +1,9 @@
+MIT+NIGGER License
+
+Copyright (c) <current year> <László Károlyi>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice, this permission notice and the word "NIGGER" shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

f2b-responder.py

@@ -0,0 +1,135 @@
+#!/usr/bin/env python
+
+from http import HTTPStatus
+from http.server import SimpleHTTPRequestHandler, ThreadingHTTPServer
+from pathlib import Path
+from random import choices
+from signal import SIGTERM, signal
+from socket import socket
+from sqlite3 import connect
+from string import ascii_lowercase
+from tempfile import gettempdir
+from threading import Thread
+from types import FrameType
+from typing import NamedTuple
+
+_F2B_DBPATH = Path('/', 'var', 'db', 'fail2ban', 'fail2ban.sqlite3')
+_CONFIG_RESULT = """\
+graph_category fail2ban
+graph_title {db_table} DB table statistics
+graph_vlabel Database record count by jail name
+graph_printf \\%3.0lf
+"""
+
+
+class _JailInfo(NamedTuple):
+    id: int
+    name: str
+
+
+class F2bRemoteRequestHandler(SimpleHTTPRequestHandler):
+    server_version = 'F2bRemoteRequestHandler'
+    _randompath = Path(
+        gettempdir(),
+        ''.join(choices(population=ascii_lowercase, k=15)))
+
+    def __init__(
+            self, request: socket, client_address: tuple[str, int],
+            server: ThreadingHTTPServer):
+        super().__init__(
+            request=request, client_address=client_address, server=server,
+            directory=str(self._randompath))
+
+    def __send_403(self) -> None:
+        'Send a HTTP 403.'
+        self.send_error(code=HTTPStatus.FORBIDDEN)
+
+    def __get_jails(self) -> list[_JailInfo]:
+        'Return the list of jails.'
+        cursor = self.__connection.cursor()
+        cursor.execute('SELECT `ROWID`, `name` FROM `jails` ORDER BY `ROWID`')
+        result = list[_JailInfo]()
+        while row := cursor.fetchone():
+            result.append(_JailInfo(*row))
+        cursor.close()
+        return result
+
+    def __send_data_response(self, body: str) -> None:
+        'Encode and send a response with a HTTP 200.'
+        body_bytes = body.encode(encoding='utf-8', errors='surrogateescape')
+        self.send_response(code=HTTPStatus.OK)
+        self.send_header(
+            keyword='Content-Type', value='text/plain; charset=utf-8')
+        self.send_header(keyword='Content-Length', value=str(len(body_bytes)))
+        self.send_header(keyword='Connection', value='close')
+        self.end_headers()
+        self.wfile.write(body_bytes)
+
+    def __get_config(self, db_table: str) -> None:
+        'Send the current plugin configuration for `db_table`.'
+        message = _CONFIG_RESULT.format(db_table=db_table)
+        for jail in self.__get_jails():
+            message += f'usercount{jail.id}.label {jail.name}\n'
+        self.__send_data_response(body=message)
+
+    def __get_data(self, db_table: str) -> None:
+        'Return organized data for the requested `db_table`.'
+        output = ''
+        cursor = self.__connection.cursor()
+        jails = self.__get_jails()
+        in_clause = ', '.join(f'\'{jail.name}\'' for jail in jails)
+        db_query = (
+            f'SELECT `jail`, COUNT(*) FROM `{db_table}` WHERE `jail` IN '
+            f'({in_clause}) GROUP BY `jail`')
+        cursor.execute(db_query)
+        result = dict[str, int]()
+        while row := cursor.fetchone():
+            jail_name, count = row
+            result[jail_name] = count
+        cursor.close()
+        for jail_id, jail_name in jails:
+            count = result.get(jail_name) or 0
+            output += f'usercount{jail_id}.value: {count}\n'
+        self.__send_data_response(body=output)
+
+    def do_GET(self) -> None:
+        'Overwriting `do_GET`.'
+        self.__connection = connect(database=_F2B_DBPATH)
+        match(self.path):
+            case '/db/bans/config/':
+                self.__get_config(db_table='bans')
+            case '/db/bips/config/':
+                self.__get_config(db_table='bips')
+            case '/db/bans/data/':
+                self.__get_data(db_table='bans')
+            case '/db/bips/data/':
+                self.__get_data(db_table='bips')
+            case _:
+                self.__send_403()
+        self.__connection.close()
+
+    do_HEAD = do_POST = __send_403
+
+
+server = ThreadingHTTPServer(
+    server_address=('', 8000), RequestHandlerClass=F2bRemoteRequestHandler,
+    bind_and_activate=True)
+
+
+def shutdown(signalnum: int, frame: FrameType | None):
+    'Shut down upon SIGTERM.'
+    print('Shutting down.')
+    server.shutdown()
+
+
+if __name__ == '__main__':
+    signal(signalnum=SIGTERM, handler=shutdown)
+    run_thread = Thread(
+        target=server.serve_forever, kwargs=dict(poll_interval=1))
+    print('Serving.')
+    run_thread.start()
+    try:
+        run_thread.join()
+    except KeyboardInterrupt:
+        pass
+    print('Server is shut down.')