chiark / gitweb /
wip
[hippotat.git] / server
diff --git a/server b/server
index 1a9049b845131db9c6148373e6f121853fd60e9a..de28624452c8dec55a20be22ad2d08e3aee0b141 100755 (executable)
--- a/server
+++ b/server
@@ -1,16 +1,35 @@
-#!/usr/bin/python2
+#!/usr/bin/python3
 
-from twisted.web.server import Site
-from twisted.web.resource import Resource
-from twisted.web.server import NOT_DONE_YET
+import signal
+signal.signal(signal.SIGINT, signal.SIG_DFL)
+
+import sys
+import os
+
+import twisted
+import twisted.internet
+import twisted.internet.endpoints
 from twisted.internet import reactor
+from twisted.web.server import NOT_DONE_YET
+from twisted.logger import LogLevel
 
-import ConfigParser
 import ipaddress
+from ipaddress import AddressValueError
+
+#import twisted.web.server import Site
+#from twisted.web.resource import Resource
+
+from optparse import OptionParser
+from configparser import ConfigParser
+from configparser import NoOptionError
+
+import collections
+
+import syslog
 
 clients = { }
 
-def ipaddress(input):
+def ipaddr(input):
   try:
     r = ipaddress.IPv4Address(input)
   except AddressValueError:
@@ -24,58 +43,238 @@ def ipnetwork(input):
     r = ipaddress.IPv6Network(input)
   return r
 
-defcfg = u'''
-[default]
-max_batch_down: 65536
-max_queue_time: 10
-max_request_time: 54
+defcfg = '''
+[DEFAULT]
+max_batch_down = 65536
+max_queue_time = 10
+max_request_time = 54
+
+[virtual]
+mtu = 1500
+# network
+# [host]
+# [relay]
+
+[server]
+ipif = userv root ipif %(host)s,%(relay)s,%(mtu)s,slip %(network)s
+addrs = 127.0.0.1 ::1
+port = 8099
 
-[global]
-max_batch_down: 262144
-max_queue_time: 121
-max_request_time: 121
+[limits]
+max_batch_down = 262144
+max_queue_time = 121
+max_request_time = 121
 '''
 
+#---------- error handling ----------
+
+def crash(err):
+  print('CRASH ', err, file=sys.stderr)
+  try: reactor.stop()
+  except twisted.internet.error.ReactorNotRunning: pass
+
+def crash_on_defer(defer):
+  defer.addErrback(lambda err: crash(err))
+
+def crash_on_critical(event):
+  if event.get('log_level') >= LogLevel.critical:
+    crash(twisted.logger.formatEvent(event))
+
+#---------- "router" ----------
+
+def route(packet, saddr, daddr):
+  print('TRACE ', saddr, daddr, packet)
+  try: client = clients[daddr]
+  except KeyError: dclient = None
+  if dclient is not None:
+    dclient.queue_outbound(packet)
+  elif saddr.is_link_local or daddr.is_link_local:
+    log_discard(packet, saddr, daddr, 'link-local')
+  elif daddr == host or daddr not in network:
+    print('TRACE INBOUND ', saddr, daddr, packet)
+    queue_inbound(packet)
+  elif daddr == relay:
+    log_discard(packet, saddr, daddr, 'relay')
+  else:
+    log_discard(packet, saddr, daddr, 'no client')
+
+def log_discard(packet, saddr, daddr, why):
+  print('DROP ', saddr, daddr, why)
+#  syslog.syslog(syslog.LOG_DEBUG,
+#                'discarded packet %s -> %s (%s)' % (saddr, daddr, why))
+
+#---------- ipif (slip subprocess) ----------
+
+class IpifProcessProtocol(twisted.internet.protocol.ProcessProtocol):
+  def __init__(self):
+    self._buffer = b''
+  def connectionMade(self): pass
+  def outReceived(self, data):
+    #print('RECV ', repr(data))
+    self._buffer += data
+    packets = slip_decode(self._buffer)
+    self._buffer = packets.pop()
+    for packet in packets:
+      if not len(packet): continue
+      (saddr, daddr) = packet_addrs(packet)
+      route(packet, saddr, daddr)
+  def processEnded(self, status):
+    status.raiseException()
+
+def start_ipif():
+  global ipif
+  ipif = IpifProcessProtocol()
+  reactor.spawnProcess(ipif,
+                       '/bin/sh',['sh','-xc', ipif_command],
+                       childFDs={0:'w', 1:'r', 2:2})
+
+def queue_inbound(packet):
+  ipif.transport.write(slip_delimiter)
+  ipif.transport.write(slip_encode(packet))
+  ipif.transport.write(slip_delimiter)
+
+#---------- SLIP handling ----------
+
+slip_end = b'\300'
+slip_esc = b'\333'
+slip_esc_end = b'\334'
+slip_esc_esc = b'\335'
+slip_delimiter = slip_end
+
+def slip_encode(packet):
+  return (packet
+          .replace(slip_esc, slip_esc + slip_esc_esc)
+          .replace(slip_end, slip_esc + slip_esc_end))
+
+def slip_decode(data):
+  print('DECODE ', repr(data))
+  out = []
+  for packet in data.split(slip_end):
+    pdata = b''
+    while True:
+      eix = packet.find(slip_esc)
+      if eix == -1:
+        pdata += packet
+        break
+      #print('ESC ', repr((pdata, packet, eix)))
+      pdata += packet[0 : eix]
+      ck = packet[eix+1]
+      if   ck == slip_esc_esc: pdata += slip_esc
+      elif ck == slip_esc_end: pdata += slip_end
+      else: raise ValueError('invalid SLIP escape')
+      packet = packet[eix+2 : ]
+    out.append(pdata)
+  print('DECODED ', repr(out))
+  return out
+
+#---------- packet parsing ----------
+
+def packet_addrs(packet):
+  version = packet[0] >> 4
+  if version == 4:
+    addrlen = 4
+    saddroff = 3*4
+    factory = ipaddress.IPv4Address
+  elif version == 6:
+    addrlen = 16
+    saddroff = 2*4
+    factory = ipaddress.IPv6Address
+  else:
+    raise ValueError('unsupported IP version %d' % version)
+  saddr = factory(packet[ saddroff           : saddroff + addrlen   ])
+  daddr = factory(packet[ saddroff + addrlen : saddroff + addrlen*2 ])
+  return (saddr, daddr)
+
+#---------- client ----------
+
 class Client():
-  def __init__(ip, cs):
+  def __init__(self, ip, cs):
     # instance data members
     self._ip = ip
     self._cs = cs
     self.pw = cfg.get(cs, 'password')
-    # plus:
-    #  .cfg[<config-key>]
-    self.cfg = { }
+    self._rq = collections.deque() # requests
+    self._pq = collections.deque() # packets
+    # plus from config:
+    #  .max_batch_down
+    #  .max_queue_time
+    #  .max_request_time
     for k in ('max_batch_down','max_queue_time','max_request_time'):
       req = cfg.getint(cs, k)
-      limit = cfg.getint('global',k)
-      self.cfg[k] = min(req, limit)
+      limit = cfg.getint('limits',k)
+      self.__dict__[k] = min(req, limit)
 
-    def process_arriving_data(d):
-      
+    def process_arriving_data(self, d):
+      for packet in slip_decode(d):
+        (saddr, daddr) = packet_addrs(packet)
+        if saddr != self._ip:
+          raise ValueError('wrong source address %s' % saddr)
+        route(packet, saddr, daddr)
 
-def process_cfg():
-  global network
-  global ourself
+    def _req_cancel(self, request):
+      request.finish()
 
-  network = ipnetwork(cfg.get('virtual','network'))
-  try:
-    ourself = cfg.get('virtual','server')
-  except ConfigParser.NoOptionError:
-    ourself = network.hosts().next()
+    def _req_error(self, err, request):
+      self._req_cancel(request)
 
-  for cs in cfg.sections():
-    if not (':' in cs or '.' in cs): continue
-    ci = ipaddress(cs)
-    if ci not in network:
-      raise ValueError('client %s not in network' % ci)
-    if ci in clients:
-      raise ValueError('multiple client cfg sections for %s' % ci)
-    clients[ci] = Client(ci, cs)
+    def queue_outbound(self, packet):
+      self._pq.append((time.monotonic(), packet))
+
+    def http_request(self, request):
+      request.setHeader('Content-Type','application/octet-stream')
+      reactor.callLater(self.max_request_time, self._req_cancel, request)
+      request.notifyFinish().addErrback(self._req_error, request)
+      self._rq.append(request)
+      self._check_outbound()
+
+    def _check_outbound(self):
+      while True:
+        try: request = self._rq[0]
+        except IndexError: request = None
+        if request and request.finished:
+          self._rq.popleft()
+          continue
+
+        # now request is an unfinished request, or None
+        try: (queuetime, packet) = self._pq[0]
+        except IndexError:
+          # no packets, oh well
+          break
+
+        age = time.monotonic() - queuetime
+        if age > self.max_queue_time:
+          self._pq.popleft()
+          continue
+
+        if request is None:
+          # no request
+          break
+
+        # request, and also some non-expired packets
+        while True:
+          try: (dummy, packet) = self._pq[0]
+          except IndexError: break
+
+          encoded = slip_encode(packet)
+          
+          if request.sentLength > 0:
+            if (request.sentLength + len(slip_delimiter)
+                + len(encoded) > self.max_batch_down):
+              break
+            request.write(slip_delimiter)
+
+          request.write(encoded)
+          self._pq.popLeft()
 
-class FormPage(Resource):
+        assert(request.sentLength)
+        self._rq.popLeft()
+        request.finish()
+        # round again, looking for more to do
+
+class IphttpResource(twisted.web.resource.Resource):
   def render_POST(self, request):
     # find client, update config, etc.
-    ci = ipaddress(request.args['i'])
+    ci = ipaddr(request.args['i'])
     c = clients[ci]
     pw = request.args['pw']
     if pw != c.pw: raise ValueError('bad password')
@@ -87,11 +286,90 @@ class FormPage(Resource):
       try: v = request.args[r]
       except KeyError: continue
       v = int(v)
-      c.cfg[w] = v
+      c.__dict__[w] = v
 
     try: d = request.args['d']
     except KeyError: d = ''
 
     c.process_arriving_data(d)
+    c.new_request(request)
+
+def start_http():
+  resource = IphttpResource()
+  sitefactory = twisted.web.server.Site(resource)
+  for addrspec in cfg.get('server','addrs').split():
+    try:
+      addr = ipaddress.IPv4Address(addrspec)
+      endpointfactory = twisted.internet.endpoints.TCP4ServerEndpoint
+    except AddressValueError:
+      addr = ipaddress.IPv6Address(addrspec)
+      endpointfactory = twisted.internet.endpoints.TCP6ServerEndpoint
+    ep = endpointfactory(reactor, cfg.getint('server','port'), addr)
+    crash_on_defer(ep.listen(sitefactory))
+
+#---------- config and setup ----------
+        
+def process_cfg():
+  global network
+  global host
+  global relay
+  global ipif_command
+
+  network = ipnetwork(cfg.get('virtual','network'))
+  if network.num_addresses < 3 + 2:
+    raise ValueError('network needs at least 2^3 addresses')
+
+  try:
+    host = cfg.get('virtual','host')
+  except NoOptionError:
+    host = next(network.hosts())
+
+  try:
+    relay = cfg.get('virtual','relay')
+  except NoOptionError:
+    for search in network.hosts():
+      if search == host: continue
+      relay = search
+      break
+
+  for cs in cfg.sections():
+    if not (':' in cs or '.' in cs): continue
+    ci = ipaddr(cs)
+    if ci not in network:
+      raise ValueError('client %s not in network' % ci)
+    if ci in clients:
+      raise ValueError('multiple client cfg sections for %s' % ci)
+    clients[ci] = Client(ci, cs)
+
+  global mtu
+  mtu = cfg.get('virtual','mtu')
+
+  iic_vars = { }
+  for k in ('host','relay','mtu','network'):
+    iic_vars[k] = globals()[k]
+
+  ipif_command = cfg.get('server','ipif', vars=iic_vars)
+
+def startup():
+  global cfg
+
+  op = OptionParser()
+  op.add_option('-c', '--config', dest='configfile',
+                default='/etc/hippottd/server.conf')
+  global opts
+  (opts, args) = op.parse_args()
+  if len(args): op.error('no non-option arguments please')
+
+  twisted.logger.globalLogPublisher.addObserver(crash_on_critical)
+
+  cfg = ConfigParser()
+  cfg.read_string(defcfg)
+  cfg.read(opts.configfile)
+  process_cfg()
+
+  start_ipif()
+  start_http()
 
-    reactor.
+startup()
+reactor.run()
+print('CRASHED (end)', file=sys.stderr)