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#===============================================================================
# Copyright 2012 NetApp, Inc. All Rights Reserved,
# contribution by Jorge Mora <mora@netapp.com>
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
#===============================================================================
"""
Pkt module
Provides the object for a packet and the string representation of the packet.
This object has an attribute for each of the layers in the packet so each layer
can be accessed directly instead of going through each layer. To access the nfs
layer object you can use 'x.nfs' instead of using 'x.ethernet.ip.tcp.rpc.nfs'
which would be very cumbersome to use. Also, since NFS can be used with either
TCP or UDP it would be harder to access the nfs object independently of
the protocol.
Packet object attributes:
Pkt(
record = Record information (frame number, etc.)
ethernet = ETHERNET II (RFC 894) object
ip = IPv4 object
tcp = TCP object
rpc = RPC object
nfs = NFS object
)
"""
import nfstest_config as c
from baseobj import BaseObj
# Module constants
__author__ = "Jorge Mora (%s)" % c.NFSTEST_AUTHOR_EMAIL
__copyright__ = "Copyright (C) 2012 NetApp, Inc."
__license__ = "GPL v2"
__version__ = "1.4"
# The order in which to display all layers in the packet
PKT_layers = [
'record',
'ethernet', 'erf', 'vlan', 'sll',
'ip', 'arp', 'rarp',
'tcp', 'udp', 'ib', 'mpa', 'ddp', 'rdmap',
'rpcordma', 'rpc', 'ntp', 'dns', 'krb',
'gssd', 'nfs', 'mount', 'portmap', 'nlm', 'gssc',
]
# Required layers for debug_repr(1)
_PKT_rlayers = {'record', 'ip', 'ib'}
# Do not display these layers for debug_repr(1)
_PKT_nlayers = {'gssd', 'gssc'}
_maxlen = len(max(PKT_layers, key=len))
class Pkt(BaseObj):
"""Packet object
Usage:
from packet.pkt import Pkt
x = Pkt()
# Check if this is an NFS packet
if x == 'nfs':
print x.nfs
"""
# Class attributes
_attrlist = tuple(PKT_layers)
# Do not use BaseObj constructor to have a little bit of
# performance improvement
def __init__(self):
self._layers = ["record"]
@property
def is_truncated(self):
return (not self.record or self.record.length_orig != self.record.length_inc)
def __eq__(self, other):
"""Comparison method used to determine if object has a given layer"""
if isinstance(other, str):
return getattr(self, other.lower(), None) is not None
return False
def __ne__(self, other):
"""Comparison method used to determine if object does not have a given layer"""
return not self.__eq__(other)
def __str__(self):
"""String representation of object
The representation depends on the verbose level set by debug_repr().
If set to 0 the generic object representation is returned.
If set to 1 the representation of is condensed into a single line.
It contains, the frame number, IP source and destination and/or the
last layer:
'1 0.386615 192.168.0.62 -> 192.168.0.17 TCP 2049 -> 708, seq: 3395733180, ack: 3294169773, ACK,SYN'
'5 0.530957 00:0c:29:54:09:ef -> ff:ff:ff:ff:ff:ff, type: 0x806'
'19 0.434370 192.168.0.17 -> 192.168.0.62 NFS v4 COMPOUND4 call SEQUENCE;PUTFH;GETATTR'
If set to 2 the representation of the object is a line for each layer:
'Pkt(
RECORD: frame 19 @ 0.434370 secs, 238 bytes on wire, 238 bytes captured
ETHERNET: 00:0c:29:54:09:ef -> e4:ce:8f:58:9f:f4, type: 0x800(IPv4)
IP: 192.168.0.17 -> 192.168.0.62, protocol: 6(TCP), len: 224
TCP: src port 708 -> dst port 2049, seq: 3294170673, ack: 3395734137, len: 172, flags: ACK,PSH
RPC: CALL(0), program: 100003, version: 4, procedure: 1, xid: 0x1437d3d5
NFS: COMPOUND4args(tag='', minorversion=1, argarray=[nfs_argop4(argop=OP_SEQUENCE, ...), ...])
)'
"""
rdebug = self.debug_repr()
if rdebug > 0:
out = "Pkt(\n" if rdebug == 2 else ''
index = 0
if rdebug == 1:
layer_list = [x for x in self._layers if x not in _PKT_nlayers]
else:
layer_list = self._layers
lastkey = len(layer_list) - 1
for key in layer_list:
value = getattr(self, key, None)
if value is not None:
if rdebug == 1 and (index == lastkey or key in _PKT_rlayers or \
(not self.ip and not self.ib and key == "ethernet")):
out += str(value)
elif rdebug == 2:
if getattr(value, "_strname", None) is not None:
# Use object's name as layer name
name = value._strname
else:
name = key.upper()
sps = " " * (_maxlen - len(name))
out += " %s:%s %s\n" % (name, sps, str(value))
if index == lastkey and getattr(value, "data", "") and key != "nfs":
sps = " " * (_maxlen - 4)
out += " DATA:%s 0x%s\n" % (sps, value.data.hex())
index += 1
out += ")\n" if rdebug == 2 else ""
else:
out = BaseObj.__str__(self)
return out
def __repr__(self):
"""Formal string representation of packet object"""
rdebug = self.debug_repr()
if rdebug > 0:
sindent = self.sindent()
out = "Pkt(\n"
# Display layers in the order in which they were added
for key in self._layers:
layer = getattr(self, key, None)
if layer is not None:
# Add indentation to every line in the
# layer's representation
value = repr(layer).replace("\n", "\n"+sindent)
out += "%s%s = %s,\n" % (sindent, key, value)
out += ")\n"
else:
out = object.__repr__(self)
return out
def add_layer(self, name, layer):
"""Add layer to name and object to the packet"""
layer._pkt = self
setattr(self, name, layer)
self._layers.append(name)
def get_layers(self):
"""Return the list of layers currently in the packet"""
# Return a tuple instead of the list so it cannot be modified
return tuple(self._layers)
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