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