From 683ae19eae7d0260baa56af5331ab446926e26cd Mon Sep 17 00:00:00 2001
From: "zer0@platinum" <zer0@platinum>
Date: Tue, 29 Dec 2009 19:22:23 +0100
Subject: [PATCH] Support GRE RFC 1701
This includes: key, gre routing infos, sequence number, ...
---
scapy/layers/l2.py | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)
diff --git a/scapy/layers/l2.py b/scapy/layers/l2.py
index 97ed5a1a..6fd1141f 100644
--- a/scapy/layers/l2.py
+++ b/scapy/layers/l2.py
@@ -348,22 +348,38 @@ class ARP(Packet):
conf.neighbor.register_l3(Ether, ARP, lambda l2,l3: getmacbyip(l3.pdst))
+class GRErouting(Packet):
+ name = "GRE routing informations"
+ fields_desc = [ ShortField("address_family",0),
+ ByteField("SRE_offset", 0),
+ FieldLenField("SRE_len", None, "routing_info", "B"),
+ StrLenField("routing_info", "", "SRE_len"),
+ ]
+
+
class GRE(Packet):
name = "GRE"
- fields_desc = [ BitField("chksumpresent",0,1),
- BitField("reserved0",0,12),
+ fields_desc = [ BitField("chksum_present",0,1),
+ BitField("routing_present",0,1),
+ BitField("key_present",0,1),
+ BitField("seqnum_present",0,1),
+ BitField("strict_route_source",0,1),
+ BitField("recursion control",0,3),
+ BitField("flags",0,5),
BitField("version",0,3),
XShortEnumField("proto", 0x0000, ETHER_TYPES),
- ConditionalField(XShortField("chksum",None),lambda pkt:pkt.chksumpresent==1),
- ConditionalField(XShortField("reserved1",None),lambda pkt:pkt.chksumpresent==1),
+ ConditionalField(XShortField("chksum",None), lambda pkt:pkt.chksum_present==1 or pkt.routing_present==1),
+ ConditionalField(XShortField("offset",None), lambda pkt:pkt.chksum_present==1 or pkt.routing_present==1),
+ ConditionalField(XIntField("key",None), lambda pkt:pkt.key_present==1),
+ ConditionalField(XIntField("seqence_number",None), lambda pkt:pkt.seqnum_present==1),
]
def post_build(self, p, pay):
p += pay
- if self.chksumpresent and self.chksum is None:
+ if self.chksum_present and self.chksum is None:
c = checksum(p)
p = p[:4]+chr((c>>8)&0xff)+chr(c&0xff)+p[6:]
return p
-
+
@@ -384,6 +400,9 @@ bind_layers( GRE, Dot1Q, proto=33024)
bind_layers( GRE, Ether, proto=1)
bind_layers( GRE, ARP, proto=2054)
bind_layers( GRE, EAPOL, proto=34958)
+bind_layers( GRE, GRErouting, { "routing_present" : 1 } )
+bind_layers( GRErouting, Raw, { "address_family" : 0, "SRE_len" : 0 })
+bind_layers( GRErouting, GRErouting, { } )
bind_layers( EAPOL, EAP, type=0)
bind_layers( LLC, STP, dsap=66, ssap=66, ctrl=3)
bind_layers( LLC, SNAP, dsap=170, ssap=170, ctrl=3)
--
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