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wireshark/epan/dissectors/packet-igrp.c
Michael Mann ad6fc87d64 Add proto_tree_add_checksum. 
This is an attempt to standardize display/handling of checksum fields for all dissectors.
The main target is for dissectors that do validation, but dissectors that just report the
checksum were also included just to make them easier to find in the future.

Bug: 10620
Bug: 12058
Ping-Bug: 8859
Change-Id: Ia8abd86e42eaf8ed50de6b173409e914b17993bf
Reviewed-on: https://code.wireshark.org/review/16380
Petri-Dish: Michael Mann <mmann78@netscape.net>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Jeff Morriss <jeff.morriss.ws@gmail.com>
Reviewed-by: Michael Mann <mmann78@netscape.net>
2016-07-21 12:35:22 +00:00

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/* packet-igrp.c
* Routines for IGRP dissection
* Copyright 2000, Paul Ionescu <paul@acorp.ro>
*
* See
*
* http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a00800c8ae1.shtml
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* Copied from packet-syslog.c
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/expert.h>
#include <epan/to_str.h>
#include <epan/ipproto.h>
void proto_register_igrp(void);
void proto_reg_handoff_igrp(void);
#define IGRP_HEADER_LENGTH 12
#define IGRP_ENTRY_LENGTH 14
static gint proto_igrp = -1;
static gint hf_igrp_update = -1;
static gint hf_igrp_as = -1;
/* Generated from convert_proto_tree_add_text.pl */
static int hf_igrp_load = -1;
static int hf_igrp_bandwidth = -1;
static int hf_igrp_command = -1;
static int hf_igrp_reliability = -1;
static int hf_igrp_network = -1;
static int hf_igrp_version = -1;
static int hf_igrp_interior_routes = -1;
static int hf_igrp_mtu = -1;
static int hf_igrp_hop_count = -1;
static int hf_igrp_exterior_routes = -1;
static int hf_igrp_delay = -1;
static int hf_igrp_checksum = -1;
static int hf_igrp_system_routes = -1;
static gint ett_igrp = -1;
static gint ett_igrp_vektor = -1;
static gint ett_igrp_net = -1;
static expert_field ei_igrp_version = EI_INIT;
static void dissect_vektor_igrp (tvbuff_t *tvb, proto_tree *igrp_vektor_tree, guint8 network);
static int dissect_igrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
{
guint8 ver_and_opcode,version,opcode,network;
gint offset=IGRP_HEADER_LENGTH;
guint16 ninterior,nsystem,nexterior;
const guint8 *ipsrc;
proto_item *ti;
proto_tree *igrp_tree, *igrp_vektor_tree;
tvbuff_t *next_tvb;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "IGRP");
col_clear(pinfo->cinfo, COL_INFO);
ver_and_opcode = tvb_get_guint8(tvb,0);
switch (ver_and_opcode) {
case 0x11:
col_set_str(pinfo->cinfo, COL_INFO, "Response" );
break;
case 0x12:
col_set_str(pinfo->cinfo, COL_INFO, "Request" );
break;
default:
col_set_str(pinfo->cinfo, COL_INFO, "Unknown version or opcode");
}
if (tree) {
ti = proto_tree_add_protocol_format(tree, proto_igrp, tvb, 0, -1,
"Cisco IGRP");
igrp_tree = proto_item_add_subtree(ti, ett_igrp);
version = (ver_and_opcode&0xf0)>>4 ; /* version is the fist half of the byte */
opcode = ver_and_opcode&0x0f ; /* opcode is the last half of the byte */
ti = proto_tree_add_item(igrp_tree, hf_igrp_version, tvb, 0, 1, ENC_BIG_ENDIAN);
if (version != 1)
expert_add_info(pinfo, ti, &ei_igrp_version);
ti = proto_tree_add_item(igrp_tree, hf_igrp_command, tvb, 0, 1, ENC_BIG_ENDIAN);
if (opcode==1)
proto_item_append_text(ti, " (Response)");
else
proto_item_append_text(ti, " (Request)");
proto_tree_add_item(igrp_tree, hf_igrp_update, tvb, 1,1, ENC_BIG_ENDIAN);
proto_tree_add_item(igrp_tree, hf_igrp_as, tvb, 2,2, ENC_BIG_ENDIAN);
ninterior = tvb_get_ntohs(tvb,4);
nsystem = tvb_get_ntohs(tvb,6);
nexterior = tvb_get_ntohs(tvb,8);
/* this is a ugly hack to find the first byte of the IP source address */
if (pinfo->net_src.type == AT_IPv4) {
ipsrc = (const guint8 *)pinfo->net_src.data;
network = ipsrc[0];
} else
network = 0; /* XXX - shouldn't happen */
ti = proto_tree_add_item(igrp_tree, hf_igrp_interior_routes, tvb, 4, 2, ENC_BIG_ENDIAN);
for( ; ninterior>0 ; ninterior-- ) {
igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_vektor);
next_tvb = tvb_new_subset(tvb, offset, IGRP_ENTRY_LENGTH, -1);
dissect_vektor_igrp (next_tvb,igrp_vektor_tree,network);
offset+=IGRP_ENTRY_LENGTH;
}
ti = proto_tree_add_item(igrp_tree, hf_igrp_system_routes, tvb, 6, 2, ENC_BIG_ENDIAN);
for( ; nsystem>0 ; nsystem-- ) {
igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_vektor);
next_tvb = tvb_new_subset(tvb, offset, IGRP_ENTRY_LENGTH, -1);
dissect_vektor_igrp (next_tvb,igrp_vektor_tree,0);
offset+=IGRP_ENTRY_LENGTH;
}
ti = proto_tree_add_item(igrp_tree, hf_igrp_exterior_routes, tvb, 8, 2, ENC_BIG_ENDIAN);
for( ; nexterior>0 ; nexterior-- ) {
igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_vektor);
next_tvb = tvb_new_subset(tvb, offset, IGRP_ENTRY_LENGTH, -1);
dissect_vektor_igrp (next_tvb,igrp_vektor_tree,0);
offset+=IGRP_ENTRY_LENGTH;
}
proto_tree_add_checksum(igrp_tree, tvb, 10, hf_igrp_checksum, -1, NULL, pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS);
}
return tvb_captured_length(tvb);
}
static void dissect_vektor_igrp (tvbuff_t *tvb, proto_tree *igrp_vektor_tree, guint8 network)
{
union {
guint8 addr_bytes[4];
guint32 addr_word;
} addr;
address ip_addr;
if (network != 0) {
/*
* Interior route; network is the high-order byte, and the three
* bytes in the vector are the lower 3 bytes.
*/
addr.addr_bytes[0]=network;
addr.addr_bytes[1]=tvb_get_guint8(tvb,0);
addr.addr_bytes[2]=tvb_get_guint8(tvb,1);
addr.addr_bytes[3]=tvb_get_guint8(tvb,2);
} else {
/*
* System or exterior route; the three bytes in the vector are
* the three high-order bytes, and the low-order byte is 0.
*/
addr.addr_bytes[0]=tvb_get_guint8(tvb,0);
addr.addr_bytes[1]=tvb_get_guint8(tvb,1);
addr.addr_bytes[2]=tvb_get_guint8(tvb,2);
addr.addr_bytes[3]=0;
}
set_address(&ip_addr, AT_IPv4, 4, &addr);
igrp_vektor_tree = proto_tree_add_subtree_format(igrp_vektor_tree, tvb, 0 ,14,
ett_igrp_net, NULL, "Entry for network %s", address_to_str(wmem_packet_scope(), &ip_addr));
proto_tree_add_ipv4(igrp_vektor_tree, hf_igrp_network, tvb, 0, 3, addr.addr_word);
proto_tree_add_item(igrp_vektor_tree, hf_igrp_delay, tvb, 3, 3, ENC_BIG_ENDIAN);
proto_tree_add_item(igrp_vektor_tree, hf_igrp_bandwidth, tvb, 6, 3, ENC_BIG_ENDIAN);
proto_tree_add_uint_format_value(igrp_vektor_tree, hf_igrp_mtu, tvb, 9, 2, tvb_get_ntohs(tvb,9), "%d bytes", tvb_get_ntohs(tvb,9));
proto_tree_add_item(igrp_vektor_tree, hf_igrp_reliability, tvb, 11, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(igrp_vektor_tree, hf_igrp_load, tvb, 12, 1, ENC_BIG_ENDIAN);
proto_tree_add_item(igrp_vektor_tree, hf_igrp_hop_count, tvb, 13, 1, ENC_BIG_ENDIAN);
}
/* Register the protocol with Wireshark */
void proto_register_igrp(void)
{
/* Setup list of header fields */
static hf_register_info hf[] = {
{ &hf_igrp_update,
{ "Update Release", "igrp.update",
FT_UINT8, BASE_DEC, NULL, 0x0 ,
"Update Release number", HFILL }
},
{ &hf_igrp_as,
{ "Autonomous System", "igrp.as",
FT_UINT16, BASE_DEC, NULL, 0x0 ,
"Autonomous System number", HFILL }
},
/* Generated from convert_proto_tree_add_text.pl */
{ &hf_igrp_version, { "IGRP Version", "igrp.version", FT_UINT8, BASE_DEC, NULL, 0xF0, NULL, HFILL }},
{ &hf_igrp_command, { "Command", "igrp.command", FT_UINT8, BASE_DEC, NULL, 0x0F, NULL, HFILL }},
{ &hf_igrp_interior_routes, { "Interior routes", "igrp.interior_routes", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_system_routes, { "System routes", "igrp.system_routes", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_exterior_routes, { "Exterior routes", "igrp.exterior_routes", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_checksum, { "Checksum", "igrp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_network, { "Network", "igrp.network", FT_IPv4, BASE_NONE, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_delay, { "Delay", "igrp.delay", FT_UINT24, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_bandwidth, { "Bandwidth", "igrp.bandwidth", FT_UINT24, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_mtu, { "MTU", "igrp.mtu", FT_UINT16, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_reliability, { "Reliability", "igrp.reliability", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_load, { "Load", "igrp.load", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
{ &hf_igrp_hop_count, { "Hop count", "igrp.hop_count", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_igrp,
&ett_igrp_vektor,
&ett_igrp_net
};
static ei_register_info ei[] = {
{ &ei_igrp_version, { "igrp.version.invalid", PI_PROTOCOL, PI_WARN, "Unknown Version, The dissection may be inaccurate", EXPFILL }},
};
expert_module_t* expert_igrp;
/* Register the protocol name and description */
proto_igrp = proto_register_protocol("Cisco Interior Gateway Routing Protocol",
"IGRP", "igrp");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_igrp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_igrp = expert_register_protocol(proto_igrp);
expert_register_field_array(expert_igrp, ei, array_length(ei));
}
void
proto_reg_handoff_igrp(void)
{
dissector_handle_t igrp_handle;
igrp_handle = create_dissector_handle(dissect_igrp, proto_igrp);
dissector_add_uint("ip.proto", IP_PROTO_IGRP, igrp_handle);
}
/* IGRP Packet structure:
HEADER structure + k * VECTOR structure
where: k = (Number of Interior routes) + (Number of System routes) + (Number of Exterior routes)
HEADER structure is 12 bytes as follows :
4 bits Version (only version 1 is defined)
4 bits Opcode (1=Replay, 2=Request)
8 bits Update Release
16 bits Autonomous system number
16 bits Number of Interior routes
16 bits Number of System routes
16 bits Number of Exterior routes
16 bits Checksum
-------
12 bytes in header
VECTOR structure is 14 bytes as follows :
24 bits Network
24 bits Delay
24 bits Bandwidth
16 bits MTU
8 bits Reliability
8 bits Load
8 bits Hop count
-------
14 bytes in 1 vector
It is interesting how is coded an ip network address in 3 bytes because IGRP is a classful routing protocol:
If it is a interior route then this 3 bytes are the final bytes, and the first one is taken from the source ip address of the ip packet
If it is a system route or a exterior route then this 3 bytes are the first three and the last byte is not important
If the Delay is 0xFFFFFF then the network is unreachable
*/
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local Variables:
* c-basic-offset: 2
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* ex: set shiftwidth=2 tabstop=8 expandtab:
* :indentSize=2:tabSize=8:noTabs=true:
*/
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