wip

[hippotat.git] / server

diff --git a/server b/server
index b3285ede37a062b0d4e1dd6bf62248a1a7ec4d7d..e813ca0b650e24f9dfe6a263f6b0b12c01d5517f 100755 (executable)
--- a/server
+++ b/server
@@ -65,12 +65,16 @@ max_request_time = 121
 
 #---------- "router" ----------
 
-def route(packet, daddr):
+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')
@@ -78,8 +82,9 @@ def route(packet, daddr):
     log_discard(packet, saddr, daddr, 'no client')
 
 def log_discard(packet, saddr, daddr, why):
-  syslog.syslog(syslog.LOG_DEBUG,
-                'discarded packet %s -> %s (%s)' % (saddr, daddr, why))
+  print('DROP ', saddr, daddr, why)
+#  syslog.syslog(syslog.LOG_DEBUG,
+#                'discarded packet %s -> %s (%s)' % (saddr, daddr, why))
 
 #---------- ipif (slip subprocess) ----------
 
@@ -88,12 +93,14 @@ class IpifProcessProtocol(twisted.internet.protocol.ProcessProtocol):
     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, daddr)
+      route(packet, saddr, daddr)
   def processEnded(self, status):
     status.raiseException()
 
@@ -101,7 +108,7 @@ def start_ipif():
   global ipif
   ipif = IpifProcessProtocol()
   reactor.spawnProcess(ipif,
-                       '/bin/sh',['sh','-c', ipif_command],
+                       '/bin/sh',['sh','-xc', ipif_command],
                        childFDs={0:'w', 1:'r', 2:2})
 
 def queue_inbound(packet):
@@ -109,6 +116,58 @@ def queue_inbound(packet):
   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():
@@ -133,7 +192,7 @@ class Client():
         (saddr, daddr) = packet_addrs(packet)
         if saddr != self._ip:
           raise ValueError('wrong source address %s' % saddr)
-        route(packet, daddr)
+        route(packet, saddr, daddr)
 
     def _req_cancel(self, request):
       request.finish()
@@ -229,7 +288,8 @@ def start_http():
       addr = ipaddress.IPv6Address(addrspec)
       endpointfactory = twisted.internet.endpoints.TCP6ServerEndpoint
     ep = endpointfactory(reactor, cfg.getint('server','port'), addr)
-    ep.listen(sitefactory)
+    defer = ep.listen(sitefactory)
+    defer.addErrback(lambda err: err.raiseException())
 
 #---------- config and setup ----------