""" TCP server that communicates with terminals """
from configparser import ConfigParser
+from importlib import import_module
from logging import getLogger
from os import umask
from socket import (
)
from struct import pack
from time import time
-from typing import Dict, List, Optional, Tuple
+from typing import Any, cast, Dict, List, Optional, Tuple, Union
import zmq
from . import common
-from .gps303proto import (
- HIBERNATION,
- LOGIN,
- inline_response,
- parse_message,
- proto_of_message,
-)
from .zmsg import Bcast, Resp
log = getLogger("gps303/collector")
MAXBUFFER: int = 4096
+class ProtoModule:
+ class Stream:
+ @staticmethod
+ def enframe(buffer: bytes) -> bytes:
+ ...
+
+ def recv(self, segment: bytes) -> List[Union[bytes, str]]:
+ ...
+
+ def close(self) -> bytes:
+ ...
+
+ @staticmethod
+ def probe_buffer(buffer: bytes) -> bool:
+ ...
+
+ @staticmethod
+ def parse_message(packet: bytes, is_incoming: bool = True) -> Any:
+ ...
+
+ @staticmethod
+ def inline_response(packet: bytes) -> Optional[bytes]:
+ ...
+
+ @staticmethod
+ def is_goodbye_packet(packet: bytes) -> bool:
+ ...
+
+ @staticmethod
+ def imei_from_packet(packet: bytes) -> Optional[str]:
+ ...
+
+ @staticmethod
+ def proto_of_message(packet: bytes) -> str:
+ ...
+
+ @staticmethod
+ def proto_by_name(name: str) -> int:
+ ...
+
+
+pmods: List[ProtoModule] = []
+
+
class Client:
"""Connected socket to the terminal plus buffer and metadata"""
def __init__(self, sock: socket, addr: Tuple[str, int]) -> None:
self.sock = sock
self.addr = addr
- self.buffer = b""
+ self.pmod: Optional[ProtoModule] = None
+ self.stream: Optional[ProtoModule.Stream] = None
self.imei: Optional[str] = None
def close(self) -> None:
log.debug("Closing fd %d (IMEI %s)", self.sock.fileno(), self.imei)
self.sock.close()
- self.buffer = b""
+ if self.stream:
+ rest = self.stream.close()
+ else:
+ rest = b""
+ if rest:
+ log.warning(
+ "%d bytes in buffer on close: %s", len(rest), rest[:64].hex()
+ )
def recv(self) -> Optional[List[Tuple[float, Tuple[str, int], bytes]]]:
"""Read from the socket and parse complete messages"""
self.imei,
)
return None
+ if self.stream is None:
+ for pmod in pmods:
+ if pmod.probe_buffer(segment):
+ self.pmod = pmod
+ self.stream = pmod.Stream()
+ break
+ if self.stream is None:
+ log.info(
+ "unrecognizable %d bytes of data %s from fd %d",
+ len(segment),
+ segment[:32].hex(),
+ self.sock.fileno(),
+ )
+ return []
when = time()
- self.buffer += segment
- if len(self.buffer) > MAXBUFFER:
- # We are receiving junk. Let's drop it or we run out of memory.
- log.warning("More than %d unparseable data, dropping", MAXBUFFER)
- self.buffer = b""
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
+ for elem in self.stream.recv(segment):
+ if isinstance(elem, bytes):
+ msgs.append((when, self.addr, elem))
+ else:
log.warning(
- 'Undecodable data (%d) "%s" from fd %d (IMEI %s)',
- framestart,
- self.buffer[:framestart][:64].hex(),
+ "%s from fd %d (IMEI %s)",
+ elem,
self.sock.fileno(),
self.imei,
)
- self.buffer = self.buffer[framestart:]
- # 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
- log.warning("Packet too short: %s", packet)
- break
- if proto_of_message(packet) == LOGIN.PROTO:
- msg = parse_message(packet)
- if isinstance(msg, LOGIN): # Can be unparseable
- self.imei = msg.imei
- log.info(
- "LOGIN from fd %d (IMEI %s)",
- self.sock.fileno(),
- self.imei,
- )
- msgs.append((when, self.addr, packet))
return msgs
def send(self, buffer: bytes) -> None:
+ assert self.stream is not None
try:
- self.sock.send(b"xx" + buffer + b"\r\n")
+ self.sock.send(self.stream.enframe(buffer))
except OSError as e:
log.error(
"Sending to fd %d (IMEI %s): %s",
def recv(
self, fd: int
- ) -> Optional[List[Tuple[Optional[str], float, Tuple[str, int], bytes]]]:
+ ) -> Optional[
+ List[Tuple[ProtoModule, Optional[str], float, Tuple[str, int], bytes]]
+ ]:
clnt = self.by_fd[fd]
msgs = clnt.recv()
if msgs is None:
return None
result = []
for when, peeraddr, packet in msgs:
- if proto_of_message(packet) == LOGIN.PROTO: # Could do blindly...
- if clnt.imei:
+ assert clnt.pmod is not None
+ if clnt.imei is None:
+ imei = clnt.pmod.imei_from_packet(packet)
+ if imei is not None:
+ log.info("LOGIN from fd %d (IMEI %s)", fd, imei)
+ clnt.imei = imei
+ oldclnt = self.by_imei.get(clnt.imei)
+ if oldclnt is not None:
+ log.info(
+ "Orphaning fd %d with the same IMEI",
+ oldclnt.sock.fileno(),
+ )
+ oldclnt.imei = None
self.by_imei[clnt.imei] = clnt
else:
log.warning(
peeraddr,
packet,
)
- result.append((clnt.imei, when, peeraddr, packet))
+ result.append((clnt.pmod, clnt.imei, when, peeraddr, packet))
log.debug(
"Received from %s (IMEI %s): %s",
peeraddr,
)
return result
- def response(self, resp: Resp) -> None:
+ def response(self, resp: Resp) -> Optional[ProtoModule]:
if resp.imei in self.by_imei:
- self.by_imei[resp.imei].send(resp.packet)
+ clnt = self.by_imei[resp.imei]
+ clnt.send(resp.packet)
+ return clnt.pmod
else:
log.info("Not connected (IMEI %s)", resp.imei)
+ return None
def runserver(conf: ConfigParser, handle_hibernate: bool = True) -> None:
+ global pmods
+ pmods = [
+ cast(ProtoModule, import_module("." + modnm, __package__))
+ for modnm in conf.get("collector", "protocols").split(",")
+ ]
# Is this https://github.com/zeromq/pyzmq/issues/1627 still not fixed?!
zctx = zmq.Context() # type: ignore
zpub = zctx.socket(zmq.PUB) # type: ignore
log.debug("Terminal gone from fd %d", sk)
tostop.append(sk)
else:
- for imei, when, peeraddr, packet in received:
- proto = proto_of_message(packet)
+ for pmod, imei, when, peeraddr, packet in received:
+ proto = pmod.proto_of_message(packet)
zpub.send(
Bcast(
proto=proto,
packet=packet,
).packed
)
- if proto == HIBERNATION.PROTO and handle_hibernate:
+ if (
+ pmod.is_goodbye_packet(packet)
+ and handle_hibernate
+ ):
log.debug(
- "HIBERNATION from fd %d (IMEI %s)",
+ "Goodbye from fd %d (IMEI %s)",
sk,
imei,
)
tostop.append(sk)
- respmsg = inline_response(packet)
+ respmsg = pmod.inline_response(packet)
if respmsg is not None:
tosend.append(
Resp(imei=imei, when=when, packet=respmsg)
else:
log.debug("Stray event: %s on socket %s", fl, sk)
# poll queue consumed, make changes now
+ for zmsg in tosend:
+ log.debug("Sending to the client: %s", zmsg)
+ rpmod = clients.response(zmsg)
+ if rpmod is not None:
+ zpub.send(
+ Bcast(
+ is_incoming=False,
+ proto=rpmod.proto_of_message(zmsg.packet),
+ when=zmsg.when,
+ imei=zmsg.imei,
+ packet=zmsg.packet,
+ ).packed
+ )
for fd in tostop:
poller.unregister(fd) # type: ignore
clients.stop(fd)
- for zmsg in tosend:
- zpub.send(
- Bcast(
- is_incoming=False,
- proto=proto_of_message(zmsg.packet),
- when=zmsg.when,
- imei=zmsg.imei,
- packet=zmsg.packet,
- ).packed
- )
- log.debug("Sending to the client: %s", zmsg)
- clients.response(zmsg)
for clntsock, clntaddr in topoll:
fd = clients.add(clntsock, clntaddr)
poller.register(fd, flags=zmq.POLLIN)