From a5d8291ba6cee9520abb501966796cc8740ee28e Mon Sep 17 00:00:00 2001
From: Guillaume Valadon <guillaume@valadon.net>
Date: Tue, 23 Dec 2014 09:59:36 +0100
Subject: [PATCH] GTP_U_Header.post_build() fixed
--HG--
branch : GTP support
---
scapy/contrib/gtp.py | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)
diff --git a/scapy/contrib/gtp.py b/scapy/contrib/gtp.py
index fcd35985..64529be2 100644
--- a/scapy/contrib/gtp.py
+++ b/scapy/contrib/gtp.py
@@ -353,7 +353,7 @@ class GTP_U_Header(Packet):
BitField("E", 0,1),
BitField("S", 0, 1),
BitField("PN", 0, 1),
- ByteEnumField("type", None, GTPmessageType),
+ ByteEnumField("gtp_type", None, GTPmessageType),
BitField("length", None, 16),
XBitField("TEID", 0, 32),
ConditionalField(XBitField("seq", 0, 16), lambda pkt:pkt.E==1 or pkt.S==1 or pkt.PN==1),
@@ -363,25 +363,14 @@ class GTP_U_Header(Packet):
def post_build(self, p, pay):
p += pay
- warning("Packet length: " + str(len(p)-8))
if self.length is None:
l = len(p)-8
- p = p[:1] + struct.pack("!i",l)+ p[4:]
- if self.type is None:
- if isinstance(self.payload, IP):
- t = 255
- else:
- warning("GTP-U Header: Not PDU detected.")
- t = 255
- p = p[:1] + struct.pack("!B",t) + p[3:]
+ p = p[:2] + struct.pack("!H", l)+ p[4:]
return p
class GTPmorethan1500(Packet):
# 3GPP TS 29.060 V9.1.0 (2009-12)
name = "GTP More than 1500"
- # GTP-U protocol is used to transmit T-PDUs between GSN pairs (or between an SGSN and an RNC in UMTS),
- # encapsulated in G-PDUs. A G-PDU is a packet including a GTP-U header and a T-PDU. The Path Protocol
- # defines the path and the GTP-U header defines the tunnel. Several tunnels may be multiplexed on a single path.
fields_desc = [ ByteEnumField("IE_Cause", "Cause", IEType),
BitField("IE", 1, 12000),]
@@ -395,7 +384,7 @@ bind_layers(GTPHeader, GTPDeletePDPContextRequest, gtp_type = 20)
bind_layers(GTPHeader, GTPDeletePDPContextResponse, gtp_type = 21)
# Bind GTP-U
bind_layers(UDP, GTP_U_Header)
-bind_layers(GTP_U_Header, IP)
+bind_layers(GTP_U_Header, IP, gtp_type = 255)
if __name__ == "__main__":
interact(mydict=globals(), mybanner="Test GTPv1 add-on v0.1")
--
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