switzerland/common/Messages.py

   1 #!/usr/bin/env python
   2
   3 # Message.py -- Switzerland protocol messages.
   4
   5 import types
   6
   7 class Message:
   8     """
   9     Message: represents each message that can be sent by Alice or Switzerland
  10     or both.  We don't instantiate this class for every message on the wire;
  11     these objects are just used to fill static dicts that the *Link classes
  12     use to look up message properties.
  13     """
  14
  15     def __init__(self, name, arguments, expects_ack, expects_reply, is_reply):
  16         assert isinstance(name, types.StringType)
  17         assert isinstance(arguments, types.ListType)
  18
  19         self.name = name
  20         self.length = len(arguments) + 1
  21         self.expects_ack = expects_ack
  22         self.expects_reply = expects_reply
  23         self.is_reply = is_reply
  24
  25         if expects_ack or expects_reply:
  26             self.length += 1   # for a sequence number
  27
  28         if is_reply:
  29             self.length += 1   # for a reply sequence number
  30
  31 alice_in_messages = {}
  32 alice_out_messages = {}
  33 switzerland_in_messages = {}
  34 switzerland_out_messages = {}
  35
  36 # Some syntactic sugar -- concisely construct each message and place it in
  37 # the correct categories.
  38 def _cmsg(name, num_args, expects_ack=False, expects_reply=False,
  39           is_reply=None):
  40     """These go in either direction."""
  41
  42     msg = Message(name, num_args, expects_ack, expects_reply, is_reply)
  43     alice_in_messages[name] = switzerland_out_messages[name] = msg
  44     alice_out_messages[name] = switzerland_in_messages[name] = msg
  45
  46 def _amsg(name, num_args, expects_ack=False, expects_reply=False,
  47           is_reply=None):
  48     """Alice sends these to Switzerland."""
  49
  50     msg = Message(name, num_args, expects_ack, expects_reply, is_reply)
  51     alice_out_messages[name] = msg
  52     switzerland_in_messages[name] = msg
  53
  54 def _smsg(name, num_args, expects_ack=False, expects_reply=False,
  55           is_reply=None, assert_len=None):
  56     """Switzerland sends these to alice."""
  57
  58     msg = Message(name, num_args, expects_ack, expects_reply, is_reply)
  59     alice_in_messages[name] = msg
  60     switzerland_out_messages[name] = msg
  61
  62 # The contents of the arguments below are purely for documentation
  63
  64 # Messages that can be sent in either direction.
  65
  66 _cmsg("ping", [], expects_ack=True)
  67 _cmsg("error-bye", ["details"])
  68 _cmsg("error-cont", ["details"], expects_ack=True)
  69 _cmsg("signoff", [])
  70 _cmsg("ack", ["seq_no"], )     # sort of a special case for not having an is_ack
  71 _cmsg("test", ["alpha", "beta", "gamma"])
  72
  73 # Alice -> Switzerland
  74
  75 _amsg("parameters",
  76       [{"clock dispersion" : 0.085, "will send actual packets": False}])
  77 _amsg("my-ip", [["my private ip", "my public ip"]], expects_reply=True)
  78 _amsg("active_flows", [["new flows"], ["deleted flows"]])
  79 _amsg("flow_stats", [("flow", {"stat": "value"})])
  80 _amsg("sent", ["flow id", "timestamp", "concatenated hashes"])
  81 _amsg("recd", ["flow id", "timestamp", "concatenated hashes"])
  82 _amsg("fi-context", [{"hash": [("timestamp", "hash", "data")]}], is_reply=True, expects_reply=True)
  83 _amsg("fo-context", [{"hash": [("timestamp", "data")]}, {"hash": ["diff1","diff2"]}], is_reply=True)
  84 _amsg("rst-radar", [[("list", "of"), ("packet", "pairs")]])
  85 _amsg("traceroute", ["destination", "type", "results"])
  86
  87 # Switzerland -> Alice
  88
  89 _smsg("debug-ipid", ["ipid"])
  90 _smsg("public-ip", ["your public ip"], is_reply=True)
  91 _smsg("new-members", [[("ip1", "firewalled", "key"), ("ip2", "firewalled", "key")]], expects_ack=True)
  92
  93 # Other client hangs up.
  94 _smsg("farewell", ["ip"], expects_ack=True)
  95 # Other clients go missing.
  96 _smsg("igcognito", [["list", "of", "ips"]], expects_ack=True)
  97
  98 _smsg("forged-in", ["flow id", [("timestamp", "hash")]], expects_reply=True)
  99 _smsg("forged-out", ["flow id", [["context"]]], expects_reply=True, assert_len=2)
 100 _smsg("forged-details", ["flow id", [("timestamp", "context", "report")]], is_reply=True)
 101
 102 # The other side isn't reporting this flow in a way that allows us to match
 103 # them.
 104 _smsg("dangling-flow", ["flow id", "opening hash"])
 105
 106 # The other side isn't reporting this flow in a way that allows us to match
 107 # them.
 108 _smsg("flow-status", ["string"])
 109
 110 # vim: set ts=4