From c58e3184e2940106d5bd880bfbe8a2efeeadd4c1 Mon Sep 17 00:00:00 2001
From: Phil <phil@secdev.org>
Date: Sun, 8 Mar 2009 10:56:22 +0100
Subject: [PATCH] Ability to reference a packet's fields in another packet's
fields description
class Test(Packet):
fields_desc = [ IntField("test1",0),
SNAP,
IntField("test2",1) ]
>>> ls(SNAP)
OUI : X3BytesField = (0)
code : XShortEnumField = (0)
>>> ls(Test)
test1 : IntField = (0)
OUI : X3BytesField = (0)
code : XShortEnumField = (0)
test2 : IntField = (1)
---
scapy/base_classes.py | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)
diff --git a/scapy/base_classes.py b/scapy/base_classes.py
index 1a77642e..221ada6b 100644
--- a/scapy/base_classes.py
+++ b/scapy/base_classes.py
@@ -122,8 +122,35 @@ class OID(Gen):
class Packet_metaclass(type):
def __new__(cls, name, bases, dct):
+ if "fields_desc" in dct: # perform resolution of references to other packets
+ current_fld = dct["fields_desc"]
+ resolved_fld = []
+ for f in current_fld:
+ if isinstance(f, Packet_metaclass): # reference to another fields_desc
+ for f2 in f.fields_desc:
+ resolved_fld.append(f2)
+ else:
+ resolved_fld.append(f)
+ else: # look for a field_desc in parent classes
+ resolved_fld = None
+ for b in bases:
+ if hasattr(b,"fields_desc"):
+ resolved_fld = b.fields_desc
+ break
+
+ if resolved_fld: # perform default value replacements
+ final_fld = []
+ for f in resolved_fld:
+ if f.name in dct:
+ f = f.copy()
+ f.default = dct[f.name]
+ del(dct[f.name])
+ final_fld.append(f)
+
+ dct["fields_desc"] = final_fld
+
newcls = super(Packet_metaclass, cls).__new__(cls, name, bases, dct)
- for f in newcls.fields_desc:
+ for f in newcls.fields_desc:
f.register_owner(newcls)
config.conf.layers.register(newcls)
return newcls
--
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