From 8b4f53ee3973ab7ba7ee844d179c329b8a477b7b Mon Sep 17 00:00:00 2001
From: Richard Neumann <mail@richard-neumann.de>
Date: Sun, 13 Feb 2022 17:04:27 +0100
Subject: [PATCH] Add BattlEye client

---
 rcon/battleye/__init__.py |   1 +
 rcon/battleye/client.py   |  30 +++++++++++
 rcon/battleye/proto.py    | 104 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 135 insertions(+)
 create mode 100644 rcon/battleye/__init__.py
 create mode 100644 rcon/battleye/client.py
 create mode 100644 rcon/battleye/proto.py

diff --git a/rcon/battleye/__init__.py b/rcon/battleye/__init__.py
new file mode 100644
index 0000000..51c33c9
--- /dev/null
+++ b/rcon/battleye/__init__.py
@@ -0,0 +1 @@
+"""BattlEye RCON implementation."""
\ No newline at end of file
diff --git a/rcon/battleye/client.py b/rcon/battleye/client.py
new file mode 100644
index 0000000..76b2e05
--- /dev/null
+++ b/rcon/battleye/client.py
@@ -0,0 +1,30 @@
+"""BattlEye RCon client."""
+
+from ipaddress import IPv4Address
+from typing import Union
+
+from rcon.battleye.proto import Command, LoginRequest
+from rcon.client import BaseClient
+
+
+__all__ = ['Client']
+
+
+Host = Union[str, IPv4Address]
+
+
+class Client(BaseClient):
+    """BattlEye RCon client."""
+
+    def communicate(self, data: bytes, *, recv: int = 4096) -> bytes:
+        """Sends and receives packets."""
+        self._socket.send(data)
+        return self._socket.recv(recv)
+
+    def login(self, passwd: str) -> bytes:
+        """Logs the user in."""
+        return self.communicate(bytes(LoginRequest.from_passwd(passwd)))
+
+    def command(self, command: str) -> bytes:
+        """Executes a command."""
+        return self.communicate(bytes(Command.from_command(command)))
diff --git a/rcon/battleye/proto.py b/rcon/battleye/proto.py
new file mode 100644
index 0000000..6019e94
--- /dev/null
+++ b/rcon/battleye/proto.py
@@ -0,0 +1,104 @@
+"""Low-level protocol stuff."""
+
+from typing import IO, NamedTuple
+from zlib import crc32
+
+
+__all__ = ['LoginRequest', 'Command']
+
+
+PREFIX = 'BE'
+SUFFIX = 0xff
+
+
+class Header(NamedTuple):
+    """Packet header."""
+
+    prefix: str
+    crc32: int
+    suffix: int
+
+    def __bytes__(self):
+        return b''.join((
+            self.prefix.encode('ascii'),
+            self.crc32.to_bytes(4, 'little'),
+            self.suffix.to_bytes(1, 'big')
+        ))
+
+    @classmethod
+    def from_payload(cls, payload: bytes):
+        """Creates a header for the given payload."""
+        return cls(
+            PREFIX,
+            crc32(SUFFIX.to_bytes(1, 'little') + payload),
+            SUFFIX
+        )
+
+    @classmethod
+    def from_bytes(cls, prefix: bytes, crc32sum: bytes, suffix: bytes):
+        """Creates a header from the given bytes."""
+        return cls(
+            prefix.decode('ascii'),
+            int.from_bytes(crc32sum, 'little'),
+            int.from_bytes(suffix, 'big')
+        )
+
+    @classmethod
+    def read(cls, file: IO):
+        """Reads the packet from a socket."""
+        return cls.from_bytes(file.read(2), file.read(4), file.read(1))
+
+
+class LoginRequest(NamedTuple):
+    """Login request packet."""
+
+    type: int
+    passwd: str
+
+    def __bytes__(self):
+        return bytes(self.header) + self.payload
+
+    @property
+    def payload(self) -> bytes:
+        """Returns the payload."""
+        return self.type.to_bytes(1, 'little') + self.passwd.encode('ascii')
+
+    @property
+    def header(self) -> Header:
+        """Returns the appropriate header."""
+        return Header.from_payload(self.payload)
+
+    @classmethod
+    def from_passwd(cls, passwd: str):
+        """Creates a login request with the given password."""
+        return cls(0x00, passwd)
+
+
+class Command(NamedTuple):
+    """Command packet."""
+
+    type: int
+    seq: int
+    command: str
+
+    def __bytes__(self):
+        return bytes(self.header) + self.payload
+
+    @property
+    def payload(self) -> bytes:
+        """Returns the payload."""
+        return b''.join((
+            self.type.to_bytes(1, 'little'),
+            self.seq.to_bytes(1, 'little'),
+            self.command.encode('ascii')
+        ))
+
+    @property
+    def header(self) -> Header:
+        """Returns the appropriate header."""
+        return Header.from_payload(self.payload)
+
+    @classmethod
+    def from_command(cls, command: str):
+        """Creates a command packet from the given command."""
+        return cls(0x01, 0x00, command)