openstack
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os-ken
Code Issues Proposed changes

packet: Better validate parameters to constructors better icmp 

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 <vjo@duke.edu>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
This commit is contained in:
Victor Orlikowski 2016-01-31 14:54:06 +09:00 committed by FUJITA Tomonori
parent 0b00bfb274
commit 8f7d302fd5
1 changed files with 11 additions and 2 deletions
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13
ryu/lib/packet/icmp.py
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@ -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