From 8ac38c611c2a6d2eedef2e568ee5eaee9b4bf1c0 Mon Sep 17 00:00:00 2001
From: Pierre LALET <pierre.lalet@cea.fr>
Date: Mon, 25 Sep 2017 11:07:38 +0200
Subject: [PATCH] Allow filters in the Packet slice / .getlayer() API
With a packet `pkt = IP() / IP(ttl=3) / IP()`, this will allow:
- pkt.getlayer(IP, ttl=3)
- pkt[IP, {"ttl": 3}]
This is particularly useful with Dot11Elt() layers, when you want a
specific value (the SSID or supported rates for example).
---
scapy/contrib/bgp.py | 13 ++++++-------
scapy/layers/eap.py | 13 ++++++-------
scapy/layers/ntp.py | 13 ++++++-------
scapy/layers/radius.py | 14 ++++++--------
scapy/packet.py | 34 +++++++++++++++++++---------------
test/regression.uts | 5 +++++
6 files changed, 48 insertions(+), 44 deletions(-)
diff --git a/scapy/contrib/bgp.py b/scapy/contrib/bgp.py
index a0a5fdad..48fcace7 100644
--- a/scapy/contrib/bgp.py
+++ b/scapy/contrib/bgp.py
@@ -619,16 +619,15 @@ class BGPCapability(six.with_metaclass(_BGPCapability_metaclass, Packet)):
ret = 1
return ret
- def getlayer(self, cls, nb=1, _track=None):
- layer = None
+ def getlayer(self, cls, nb=1, _track=None, **flt):
if cls == BGPCapability:
for cap_class in _capabilities_registry:
- if isinstance(self, _capabilities_registry[cap_class]):
- layer = self
- break
+ if isinstance(self, _capabilities_registry[cap_class]) and \
+ all(self.getfieldval(fldname) == fldvalue
+ for fldname, fldvalue in flt.iteritems()):
+ return self
else:
- layer = Packet.getlayer(self, cls, nb, _track)
- return layer
+ return Packet.getlayer(self, cls, nb, _track, **flt)
def post_build(self, p, pay):
length = 0
diff --git a/scapy/layers/eap.py b/scapy/layers/eap.py
index b441ff44..d86b78a1 100644
--- a/scapy/layers/eap.py
+++ b/scapy/layers/eap.py
@@ -248,16 +248,15 @@ class EAP(Packet):
ret = 1
return ret
- def getlayer(self, cls, nb=1, _track=None):
- layer = None
+ def getlayer(self, cls, nb=1, _track=None, **flt):
if cls == EAP:
for eap_class in EAP.registered_methods.values():
- if isinstance(self, eap_class):
- layer = self
- break
+ if isinstance(self, eap_class) and \
+ all(self.getfieldval(fldname) == fldvalue
+ for fldname, fldvalue in flt.iteritems()):
+ return self
else:
- layer = Packet.getlayer(self, cls, nb, _track)
- return layer
+ return Packet.getlayer(self, cls, nb, _track, **flt)
def answers(self, other):
if isinstance(other, EAP):
diff --git a/scapy/layers/ntp.py b/scapy/layers/ntp.py
index 2e75067e..a9512d5f 100644
--- a/scapy/layers/ntp.py
+++ b/scapy/layers/ntp.py
@@ -255,21 +255,20 @@ class NTP(Packet):
ret = 1
return ret
- def getlayer(self, cls, nb=1, _track=None):
+ def getlayer(self, cls, nb=1, _track=None, **flt):
ntp_classes = [
get_cls("NTPHeader"),
get_cls("NTPControl"),
get_cls("NTPPrivate")
]
- layer = None
if cls == NTP:
for ntp_class in ntp_classes:
- if isinstance(self, ntp_class):
- layer = self
- break
+ if isinstance(self, ntp_class) and \
+ all(self.getfieldval(fldname) == fldvalue
+ for fldname, fldvalue in flt.iteritems()):
+ return self
else:
- layer = Packet.getlayer(self, cls, nb, _track)
- return layer
+ return Packet.getlayer(self, cls, nb, _track, **flt)
def mysummary(self):
return self.sprintf("NTP v%ir,NTP.version%, %NTP.mode%")
diff --git a/scapy/layers/radius.py b/scapy/layers/radius.py
index 9b7507fb..118233c3 100644
--- a/scapy/layers/radius.py
+++ b/scapy/layers/radius.py
@@ -278,17 +278,15 @@ class RadiusAttribute(Packet):
return True
return False
- def getlayer(self, cls, nb=1, _track=None):
- layer = None
+ def getlayer(self, cls, nb=1, _track=None, **flt):
if cls == RadiusAttribute:
for attr_class in RadiusAttribute.registered_attributes.values():
- if isinstance(self, attr_class):
- layer = self
- break
+ if isinstance(self, attr_class) and \
+ all(self.getfieldval(fldname) == fldvalue
+ for fldname, fldvalue in flt.iteritems()):
+ return self
else:
- layer = Packet.getlayer(self, cls, nb, _track)
- return layer
-
+ return Packet.getlayer(self, cls, nb, _track, **flt)
def post_build(self, p, pay):
length = self.len
diff --git a/scapy/packet.py b/scapy/packet.py
index 326f15b1..50fe67a4 100644
--- a/scapy/packet.py
+++ b/scapy/packet.py
@@ -888,8 +888,12 @@ class Packet(six.with_metaclass(Packet_metaclass, BasePacket)):
if ret:
return ret
return self.payload.haslayer(cls)
- def getlayer(self, cls, nb=1, _track=None):
- """Return the nb^th layer that is an instance of cls."""
+
+ def getlayer(self, cls, nb=1, _track=None, **flt):
+ """Return the nb^th layer that is an instance of cls, matching flt
+values.
+
+ """
if isinstance(cls, int):
nb = cls+1
cls = None
@@ -898,13 +902,15 @@ class Packet(six.with_metaclass(Packet_metaclass, BasePacket)):
else:
ccls,fld = cls,None
if cls is None or self.__class__ == cls or self.__class__.__name__ == ccls:
- if nb == 1:
- if fld is None:
- return self
+ if all(self.getfieldval(fldname) == fldvalue
+ for fldname, fldvalue in flt.iteritems()):
+ if nb == 1:
+ if fld is None:
+ return self
+ else:
+ return self.getfieldval(fld)
else:
- return self.getfieldval(fld)
- else:
- nb -=1
+ nb -=1
for f in self.packetfields:
fvalue_gen = self.getfieldval(f.name)
if fvalue_gen is None:
@@ -918,7 +924,7 @@ class Packet(six.with_metaclass(Packet_metaclass, BasePacket)):
if ret is not None:
return ret
nb = track[0]
- return self.payload.getlayer(cls,nb,_track=_track)
+ return self.payload.getlayer(cls, nb=nb, _track=_track, **flt)
def firstlayer(self):
q = self
@@ -930,13 +936,11 @@ class Packet(six.with_metaclass(Packet_metaclass, BasePacket)):
if isinstance(cls, slice):
lname = cls.start
if cls.stop:
- ret = self.getlayer(cls.start, cls.stop)
+ ret = self.getlayer(cls.start, nb=cls.stop, **(cls.step or {}))
else:
- ret = self.getlayer(cls.start)
- if ret is None and cls.step is not None:
- ret = cls.step
+ ret = self.getlayer(cls.start, **(cls.step or {}))
else:
- lname=cls
+ lname = cls
ret = self.getlayer(cls)
if ret is None:
if isinstance(lname, Packet_metaclass):
@@ -1287,7 +1291,7 @@ class NoPayload(Packet):
return isinstance(other, NoPayload) or isinstance(other, conf.padding_layer)
def haslayer(self, cls):
return 0
- def getlayer(self, cls, nb=1, _track=None):
+ def getlayer(self, cls, nb=1, _track=None, **flt):
if _track is not None:
_track.append(nb)
return None
diff --git a/test/regression.uts b/test/regression.uts
index 43e5543a..dff21aa8 100644
--- a/test/regression.uts
+++ b/test/regression.uts
@@ -8645,6 +8645,11 @@ Dot11(type=0, subtype=1).answers(query) == True
assert Dot11Elt(info="scapy").summary() == "SSID='scapy'"
assert Dot11Elt(ID=1).mysummary() == ""
+= Multiple Dot11Elt layers
+pkt = Dot11() / Dot11Beacon() / Dot11Elt(ID="Rates") / Dot11Elt(ID="SSID", info="Scapy")
+assert pkt[Dot11Elt::{"ID": 0}].info == "Scapy"
+assert pkt.getlayer(Dot11Elt, ID=0).info == "Scapy"
+
= Dot11WEP - build
~ crypto
conf.wepkey = ""
--
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