According to RFC 4884 (which supersedes RFC 792), the Destination Unreachable and Time Exceeded ICMP message get a new “length” field. This length field, for ICMPv4, is interpreted in 32 bit units.
In the constructor, we cannot validate that the length specified matches the length of the data passed; the length may need to be larger (in 32 bit units) in order to accommodate the data that is actually being sent. We *should*, however, ensure that the data_len parameter passed fits into a single byte. It may make sense to document the fact that the length is specified 32 bit units, for when users of the icmp class get a ValueError back from these constructors. Signed-off-by: Victor J. Orlikowski <[email protected]> diff --git a/ryu/lib/packet/icmp.py b/ryu/lib/packet/icmp.py index 57b153c..1a6cd76 100644 --- a/ryu/lib/packet/icmp.py +++ b/ryu/lib/packet/icmp.py @@ -214,7 +214,12 @@ class dest_unreach(stringify.StringifyMixin): def __init__(self, data_len=0, mtu=0, data=None): super(dest_unreach, self).__init__() - self.data_len = data_len + + if ((data_len >= 0) and (data_len <= 255)): + self.data_len = data_len + else: + raise ValueError('Specified data length (%d) is invalid.' % data_len) + self.mtu = mtu self.data = data @@ -273,7 +278,11 @@ class TimeExceeded(stringify.StringifyMixin): _MIN_LEN = struct.calcsize(_PACK_STR) def __init__(self, data_len=0, data=None): - self.data_len = data_len + if ((data_len >= 0) and (data_len <= 255)): + self.data_len = data_len + else: + raise ValueError('Specified data length (%d) is invalid.' % data_len) + self.data = data @classmethod Best, Victor -- Victor J. Orlikowski <> vjo@[cs.]duke.edu ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Ryu-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/ryu-devel
