gps303/collector.py

   1 """ TCP server that communicates with terminals """
   2
   3 from configparser import ConfigParser
   4 from logging import getLogger
   5 from os import umask
   6 from socket import (
   7     socket,
   8     AF_INET6,
   9     SOCK_STREAM,
  10     SOL_SOCKET,
  11     SO_KEEPALIVE,
  12     SO_REUSEADDR,
  13 )
  14 from struct import pack
  15 from time import time
  16 from typing import Dict, List, Optional, Tuple
  17 import zmq
  18
  19 from . import common
  20 from .gps303proto import (
  21     GPS303Conn,
  22     StreamError,
  23     HIBERNATION,
  24     LOGIN,
  25     inline_response,
  26     parse_message,
  27     proto_of_message,
  28 )
  29 from .zmsg import Bcast, Resp
  30
  31 log = getLogger("gps303/collector")
  32
  33 MAXBUFFER: int = 4096
  34
  35
  36 class Client:
  37     """Connected socket to the terminal plus buffer and metadata"""
  38
  39     def __init__(self, sock: socket, addr: Tuple[str, int]) -> None:
  40         self.sock = sock
  41         self.addr = addr
  42         self.stream = GPS303Conn()
  43         self.imei: Optional[str] = None
  44
  45     def close(self) -> None:
  46         log.debug("Closing fd %d (IMEI %s)", self.sock.fileno(), self.imei)
  47         self.sock.close()
  48         rest = self.stream.close()
  49         if rest:
  50             log.warning("%d bytes in buffer on close: %s", len(rest), rest)
  51
  52     def recv(self) -> Optional[List[Tuple[float, Tuple[str, int], bytes]]]:
  53         """Read from the socket and parse complete messages"""
  54         try:
  55             segment = self.sock.recv(MAXBUFFER)
  56         except OSError as e:
  57             log.warning(
  58                 "Reading from fd %d (IMEI %s): %s",
  59                 self.sock.fileno(),
  60                 self.imei,
  61                 e,
  62             )
  63             return None
  64         if not segment:  # Terminal has closed connection
  65             log.info(
  66                 "EOF reading from fd %d (IMEI %s)",
  67                 self.sock.fileno(),
  68                 self.imei,
  69             )
  70             return None
  71         when = time()
  72         while True:
  73             try:
  74                 return [
  75                     (when, self.addr, packet)
  76                     for packet in self.stream.recv(segment)
  77                 ]
  78             except StreamError as e:
  79                 log.warning(
  80                     "%s from fd %d (IMEI %s)", e, self.sock.fileno(), self.imei
  81                 )
  82
  83     def send(self, buffer: bytes) -> None:
  84         try:
  85             self.sock.send(self.stream.enframe(buffer))
  86         except OSError as e:
  87             log.error(
  88                 "Sending to fd %d (IMEI %s): %s",
  89                 self.sock.fileno(),
  90                 self.imei,
  91                 e,
  92             )
  93
  94     def set_imei(self, imei: str) -> None:
  95         self.imei = imei
  96
  97
  98 class Clients:
  99     def __init__(self) -> None:
 100         self.by_fd: Dict[int, Client] = {}
 101         self.by_imei: Dict[str, Client] = {}
 102
 103     def add(self, clntsock: socket, clntaddr: Tuple[str, int]) -> int:
 104         fd = clntsock.fileno()
 105         log.info("Start serving fd %d from %s", fd, clntaddr)
 106         self.by_fd[fd] = Client(clntsock, clntaddr)
 107         return fd
 108
 109     def stop(self, fd: int) -> None:
 110         clnt = self.by_fd[fd]
 111         log.info("Stop serving fd %d (IMEI %s)", clnt.sock.fileno(), clnt.imei)
 112         clnt.close()
 113         if clnt.imei:
 114             del self.by_imei[clnt.imei]
 115         del self.by_fd[fd]
 116
 117     def recv(
 118         self, fd: int
 119     ) -> Optional[List[Tuple[Optional[str], float, Tuple[str, int], bytes]]]:
 120         clnt = self.by_fd[fd]
 121         msgs = clnt.recv()
 122         if msgs is None:
 123             return None
 124         result = []
 125         for when, peeraddr, packet in msgs:
 126             if proto_of_message(packet) == LOGIN.PROTO:
 127                 msg = parse_message(packet)
 128                 if isinstance(msg, LOGIN):  # Can be unparseable
 129                     if clnt.imei is None:
 130                         clnt.imei = msg.imei
 131                         log.info(
 132                             "LOGIN from fd %d (IMEI %s)",
 133                             clnt.sock.fileno(),
 134                             clnt.imei,
 135                         )
 136                         oldclnt = self.by_imei.get(clnt.imei)
 137                         if oldclnt is not None:
 138                             log.info(
 139                                 "Orphaning fd %d with the same IMEI",
 140                                 oldclnt.sock.fileno(),
 141                             )
 142                             oldclnt.imei = None
 143                     self.by_imei[clnt.imei] = clnt
 144                 else:
 145                     log.warning(
 146                         "Login message from %s: %s, but client imei unfilled",
 147                         peeraddr,
 148                         packet,
 149                     )
 150             result.append((clnt.imei, when, peeraddr, packet))
 151             log.debug(
 152                 "Received from %s (IMEI %s): %s",
 153                 peeraddr,
 154                 clnt.imei,
 155                 packet.hex(),
 156             )
 157         return result
 158
 159     def response(self, resp: Resp) -> None:
 160         if resp.imei in self.by_imei:
 161             self.by_imei[resp.imei].send(resp.packet)
 162         else:
 163             log.info("Not connected (IMEI %s)", resp.imei)
 164
 165
 166 def runserver(conf: ConfigParser, handle_hibernate: bool = True) -> None:
 167     # Is this https://github.com/zeromq/pyzmq/issues/1627 still not fixed?!
 168     zctx = zmq.Context()  # type: ignore
 169     zpub = zctx.socket(zmq.PUB)  # type: ignore
 170     zpull = zctx.socket(zmq.PULL)  # type: ignore
 171     oldmask = umask(0o117)
 172     zpub.bind(conf.get("collector", "publishurl"))
 173     zpull.bind(conf.get("collector", "listenurl"))
 174     umask(oldmask)
 175     tcpl = socket(AF_INET6, SOCK_STREAM)
 176     tcpl.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
 177     tcpl.bind(("", conf.getint("collector", "port")))
 178     tcpl.listen(5)
 179     tcpfd = tcpl.fileno()
 180     poller = zmq.Poller()  # type: ignore
 181     poller.register(zpull, flags=zmq.POLLIN)
 182     poller.register(tcpfd, flags=zmq.POLLIN)
 183     clients = Clients()
 184     try:
 185         while True:
 186             tosend = []
 187             topoll = []
 188             tostop = []
 189             events = poller.poll(1000)
 190             for sk, fl in events:
 191                 if sk is zpull:
 192                     while True:
 193                         try:
 194                             msg = zpull.recv(zmq.NOBLOCK)
 195                             zmsg = Resp(msg)
 196                             tosend.append(zmsg)
 197                         except zmq.Again:
 198                             break
 199                 elif sk == tcpfd:
 200                     clntsock, clntaddr = tcpl.accept()
 201                     clntsock.setsockopt(SOL_SOCKET, SO_KEEPALIVE, 1)
 202                     topoll.append((clntsock, clntaddr))
 203                 elif fl & zmq.POLLIN:
 204                     received = clients.recv(sk)
 205                     if received is None:
 206                         log.debug("Terminal gone from fd %d", sk)
 207                         tostop.append(sk)
 208                     else:
 209                         for imei, when, peeraddr, packet in received:
 210                             proto = proto_of_message(packet)
 211                             zpub.send(
 212                                 Bcast(
 213                                     proto=proto,
 214                                     imei=imei,
 215                                     when=when,
 216                                     peeraddr=peeraddr,
 217                                     packet=packet,
 218                                 ).packed
 219                             )
 220                             if proto == HIBERNATION.PROTO and handle_hibernate:
 221                                 log.debug(
 222                                     "HIBERNATION from fd %d (IMEI %s)",
 223                                     sk,
 224                                     imei,
 225                                 )
 226                                 tostop.append(sk)
 227                             respmsg = inline_response(packet)
 228                             if respmsg is not None:
 229                                 tosend.append(
 230                                     Resp(imei=imei, when=when, packet=respmsg)
 231                                 )
 232                 else:
 233                     log.debug("Stray event: %s on socket %s", fl, sk)
 234             # poll queue consumed, make changes now
 235             for zmsg in tosend:
 236                 zpub.send(
 237                     Bcast(
 238                         is_incoming=False,
 239                         proto=proto_of_message(zmsg.packet),
 240                         when=zmsg.when,
 241                         imei=zmsg.imei,
 242                         packet=zmsg.packet,
 243                     ).packed
 244                 )
 245                 log.debug("Sending to the client: %s", zmsg)
 246                 clients.response(zmsg)
 247             for fd in tostop:
 248                 poller.unregister(fd)  # type: ignore
 249                 clients.stop(fd)
 250             for clntsock, clntaddr in topoll:
 251                 fd = clients.add(clntsock, clntaddr)
 252                 poller.register(fd, flags=zmq.POLLIN)
 253     except KeyboardInterrupt:
 254         zpub.close()
 255         zpull.close()
 256         zctx.destroy()  # type: ignore
 257         tcpl.close()
 258
 259
 260 if __name__.endswith("__main__"):
 261     runserver(common.init(log))