from enum import Enum
from inspect import isclass
from struct import error, pack, unpack
+from time import time
from typing import (
Any,
Callable,
)
__all__ = (
+ "GPS303Conn",
+ "StreamError",
"class_by_prefix",
"inline_response",
"parse_message",
"UNKNOWN_B3",
)
+### Deframer ###
+
+MAXBUFFER: int = 4096
+
+
+class StreamError(Exception):
+ pass
+
+
+class GPS303Conn:
+ def __init__(self) -> None:
+ self.buffer = b""
+
+ @staticmethod
+ def enframe(buffer: bytes) -> bytes:
+ return b"xx" + buffer + b"\r\n"
+
+ def recv(self, segment: bytes) -> List[bytes]:
+ when = time()
+ self.buffer += segment
+ if len(self.buffer) > MAXBUFFER:
+ # We are receiving junk. Let's drop it or we run out of memory.
+ self.buffer = b""
+ raise StreamError(
+ f"More than {MAXBUFFER} unparseable data, dropping"
+ )
+ msgs = []
+ while True:
+ framestart = self.buffer.find(b"xx")
+ if framestart == -1: # No frames, return whatever we have
+ break
+ if framestart > 0: # Should not happen, report
+ self.buffer = self.buffer[framestart:]
+ raise StreamError(
+ f'Undecodable data ({framestart}) "{self.buffer[:framestart][:64].hex()}"'
+ )
+ # At this point, buffer starts with a packet
+ if len(self.buffer) < 6: # no len and proto - cannot proceed
+ break
+ exp_end = self.buffer[2] + 3 # Expect '\r\n' here
+ frameend = 0
+ # Length field can legitimeely be much less than the
+ # length of the packet (e.g. WiFi positioning), but
+ # it _should not_ be greater. Still sometimes it is.
+ # Luckily, not by too much: by maybe two or three bytes?
+ # Do this embarrassing hack to avoid accidental match
+ # of some binary data in the packet against '\r\n'.
+ while True:
+ frameend = self.buffer.find(b"\r\n", frameend + 1)
+ if frameend == -1 or frameend >= (
+ exp_end - 3
+ ): # Found realistic match or none
+ break
+ if frameend == -1: # Incomplete frame, return what we have
+ break
+ packet = self.buffer[2:frameend]
+ self.buffer = self.buffer[frameend + 2 :]
+ if len(packet) < 2: # frameend comes too early
+ raise StreamError(f"Packet too short: {packet.hex()}")
+ msgs.append(packet)
+ return msgs
+
+ def close(self) -> bytes:
+ ret = self.buffer
+ self.buffer = b""
+ return ret
+
+
+### Parser/Constructor ###
+
class DecodeError(Exception):
def __init__(self, e: Exception, **kwargs: Any) -> None:
setattr(self, k, v)
+def maybe(typ: type) -> Callable[[Any], Any]:
+ return lambda x: None if x is None else typ(x)
+
+
def intx(x: Union[str, int]) -> int:
if isinstance(x, str):
x = int(x, 0)
@property
def packed(self) -> bytes:
payload = self.encode()
- length = len(payload) + 1
+ length = getattr(self, "length", len(payload) + 1)
return pack("BB", length, self.PROTO) + payload
PROTO = 0x01
RESPOND = Respond.INL
# Default response for ACK, can also respond with STOP_UPLOAD
+ IN_KWARGS = (("imei", str, "0000000000000000"), ("ver", int, 0))
def in_decode(self, length: int, payload: bytes) -> None:
- self.imei = payload[:16].hex()
- self.ver = payload[16]
+ self.imei = payload[:8].ljust(8, b"\0").hex()
+ self.ver = payload[8]
+
+ def in_encode(self) -> bytes:
+ return bytes.fromhex(self.imei).ljust(8, b"\0")[:8] + pack(
+ "B", self.ver
+ )
class SUPERVISION(GPS303Pkt):
class STATUS(GPS303Pkt):
PROTO = 0x13
RESPOND = Respond.EXT
+ IN_KWARGS = (
+ ("batt", int, 100),
+ ("ver", int, 0),
+ ("timezone", int, 0),
+ ("intvl", int, 0),
+ ("signal", maybe(int), None),
+ )
OUT_KWARGS = (("upload_interval", int, 25),)
def in_decode(self, length: int, payload: bytes) -> None:
else:
self.signal = None
+ def in_encode(self) -> bytes:
+ return pack("BBBB", self.batt, self.ver, self.timezone, self.intvl) + (
+ b"" if self.signal is None else pack("B", self.signal)
+ )
+
def out_encode(self) -> bytes: # Set interval in minutes
return pack("B", self.upload_interval)
class HIBERNATION(GPS303Pkt): # Server can send to send devicee to sleep
PROTO = 0x14
+ def in_encode(self) -> bytes:
+ return b""
+
class RESET(GPS303Pkt):
# Device sends when it got reset SMS
class _WIFI_POSITIONING(GPS303Pkt):
+ IN_KWARGS: Tuple[Tuple[str, Callable[[Any], Any], Any], ...] = (
+ # IN_KWARGS = (
+ ("dtime", bytes, b"\0\0\0\0\0\0"),
+ ("wifi_aps", list, []),
+ ("mcc", int, 0),
+ ("mnc", int, 0),
+ ("gsm_cells", list, []),
+ )
+
def in_decode(self, length: int, payload: bytes) -> None:
self.dtime = payload[:6]
if self.dtime == b"\0\0\0\0\0\0":
)
self.gsm_cells.append((locac, cellid, -sigstr))
+ def in_encode(self) -> bytes:
+ self.length = len(self.wifi_aps)
+ return b"".join(
+ [
+ self.dtime,
+ b"".join(
+ [
+ bytes.fromhex(mac.replace(":", "")).ljust(6, b"\0")[:6]
+ + pack("B", -sigstr)
+ for mac, sigstr in self.wifi_aps
+ ]
+ ),
+ pack("!BHB", len(self.gsm_cells), self.mcc, self.mnc),
+ b"".join(
+ [
+ pack("!HHB", locac, cellid, -sigstr)
+ for locac, cellid, sigstr in self.gsm_cells
+ ]
+ ),
+ ]
+ )
+
class WIFI_OFFLINE_POSITIONING(_WIFI_POSITIONING):
PROTO = 0x17
+ [b";".join([el.encode() for el in self.phonenumbers])]
)
+ def in_encode(self) -> bytes:
+ return b""
+
class SYNCHRONOUS_WHITELIST(GPS303Pkt):
PROTO = 0x58
projects / loctrkd.git / blobdiff