forked from osmocom/wireshark
250 lines
7.8 KiB
C
250 lines
7.8 KiB
C
/* packet-igrp.c
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* Routines for IGRP dissection
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* Copyright 2000, Paul Ionescu <paul@acorp.ro>
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*
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* $Id: packet-igrp.c,v 1.14 2003/12/21 05:51:33 jmayer Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1998 Gerald Combs
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*
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* Copied from packet-syslog.c
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#include <string.h>
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#include <glib.h>
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#include <epan/packet.h>
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#include "ipproto.h"
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#define IGRP_HEADER_LENGTH 12
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#define IGRP_ENTRY_LENGTH 14
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static gint proto_igrp = -1;
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static gint hf_igrp_update = -1;
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static gint hf_igrp_as = -1;
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static gint ett_igrp = -1;
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static gint ett_igrp_vektor = -1;
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static gint ett_igrp_net = -1;
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static void dissect_vektor_igrp (tvbuff_t *tvb, proto_tree *igrp_vektor_tree, guint8 network);
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static void dissect_igrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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guint8 ver_and_opcode,version,opcode,update,network;
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gint offset=IGRP_HEADER_LENGTH;
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guint16 as,net1,net2,net3;
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proto_item *ti;
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proto_tree *igrp_tree, *igrp_vektor_tree;
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tvbuff_t *next_tvb;
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "IGRP");
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if (check_col(pinfo->cinfo, COL_INFO))
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col_clear(pinfo->cinfo, COL_INFO);
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ver_and_opcode = tvb_get_guint8(tvb,0);
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update = tvb_get_guint8(tvb,1);
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as = tvb_get_ntohs(tvb,2);
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if (check_col(pinfo->cinfo, COL_INFO)) {
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switch (ver_and_opcode) {
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case 0x11:
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col_add_fstr(pinfo->cinfo, COL_INFO, "Response" );
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break;
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case 0x12:
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col_add_fstr(pinfo->cinfo, COL_INFO, "Request" );
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break;
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default:
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col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown version or opcode");
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}
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}
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_igrp, tvb, 0, -1,
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"Cisco IGRP");
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igrp_tree = proto_item_add_subtree(ti, ett_igrp);
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version = (ver_and_opcode&0xf0)>>4 ; /* version is the fist half of the byte */
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opcode = ver_and_opcode&0x0f ; /* opcode is the last half of the byte */
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proto_tree_add_text(igrp_tree, tvb, 0,1,"IGRP Version : %d %s",version,(version==1?" ":" - Unknown Version, The dissection may be innacurate"));
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proto_tree_add_text(igrp_tree, tvb, 0,1,"Command : %d %s",opcode,(opcode==1?"(Response)":"(Request)"));
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proto_tree_add_uint(igrp_tree, hf_igrp_update, tvb, 1,1, update);
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proto_tree_add_uint(igrp_tree, hf_igrp_as, tvb, 2,2,as);
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net1 = tvb_get_ntohs(tvb,4);
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net2 = tvb_get_ntohs(tvb,6);
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net3 = tvb_get_ntohs(tvb,8);
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/* this is a ugly hack to find the first byte of the IP source address */
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network = pinfo->net_src.data[0];
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ti = proto_tree_add_text(igrp_tree, tvb, 4,2,"Interior routes : %d",net1);
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for( ; net1>0 ; net1-- )
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{
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igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_vektor);
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next_tvb = tvb_new_subset(tvb, offset, IGRP_ENTRY_LENGTH, -1);
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dissect_vektor_igrp (next_tvb,igrp_vektor_tree,network);
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offset+=IGRP_ENTRY_LENGTH;
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}
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ti = proto_tree_add_text(igrp_tree, tvb, 6,2,"System routes : %d",net2);
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for( ; net2>0 ; net2-- )
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{
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igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_vektor);
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next_tvb = tvb_new_subset(tvb, offset, IGRP_ENTRY_LENGTH, -1);
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dissect_vektor_igrp (next_tvb,igrp_vektor_tree,0);
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offset+=IGRP_ENTRY_LENGTH;
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}
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ti = proto_tree_add_text(igrp_tree, tvb, 8,2,"Exterior routes : %d",net3);
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for( ; net3>0 ; net3-- )
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{
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igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_vektor);
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next_tvb = tvb_new_subset(tvb, offset, IGRP_ENTRY_LENGTH, -1);
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dissect_vektor_igrp (next_tvb,igrp_vektor_tree,0);
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offset+=IGRP_ENTRY_LENGTH;
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}
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proto_tree_add_text(igrp_tree, tvb, 10,2,"Checksum = 0x%4x",tvb_get_ntohs(tvb,10));
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}
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return;
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}
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static void dissect_vektor_igrp (tvbuff_t *tvb, proto_tree *igrp_vektor_tree, guint8 network)
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{
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proto_item *ti;
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guint8 *ptr_addr,addr[5];
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addr[0]=network;
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addr[1]=tvb_get_guint8(tvb,0);
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addr[2]=tvb_get_guint8(tvb,1);
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addr[3]=tvb_get_guint8(tvb,2);
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addr[4]=0;
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ptr_addr=addr;
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if (network==0) ptr_addr=&addr[1];
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ti = proto_tree_add_text (igrp_vektor_tree, tvb, 0 ,14,
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"Entry for network %s", ip_to_str(ptr_addr)) ;
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igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_net);
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proto_tree_add_text (igrp_vektor_tree, tvb, 0 ,3,"Network = %s",ip_to_str(ptr_addr)) ;
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proto_tree_add_text (igrp_vektor_tree, tvb, 3 ,3,"Delay = %d",tvb_get_ntoh24(tvb,3)) ;
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proto_tree_add_text (igrp_vektor_tree, tvb, 6 ,3,"Bandwidth = %d",tvb_get_ntoh24(tvb,6)) ;
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proto_tree_add_text (igrp_vektor_tree, tvb, 9 ,2,"MTU = %d bytes",tvb_get_ntohs(tvb,9)) ;
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proto_tree_add_text (igrp_vektor_tree, tvb, 11,1,"Reliability = %d",tvb_get_guint8(tvb,11)) ;
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proto_tree_add_text (igrp_vektor_tree, tvb, 12,1,"Load = %d",tvb_get_guint8(tvb,12)) ;
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proto_tree_add_text (igrp_vektor_tree, tvb, 13,1,"Hop count = %d hops",tvb_get_guint8(tvb,13)) ;
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}
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/* Register the protocol with Ethereal */
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void proto_register_igrp(void)
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{
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/* Setup list of header fields */
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static hf_register_info hf[] = {
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{ &hf_igrp_update,
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{ "Update Release", "igrp.update",
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FT_UINT8, BASE_DEC, NULL, 0x0 ,
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"Update Release number", HFILL }
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},
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{ &hf_igrp_as,
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{ "Autonomous System", "igrp.as",
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FT_UINT16, BASE_DEC, NULL, 0x0 ,
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"Autonomous System number", HFILL }
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}
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};
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/* Setup protocol subtree array */
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static gint *ett[] = {
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&ett_igrp,
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&ett_igrp_vektor,
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&ett_igrp_net
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};
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/* Register the protocol name and description */
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proto_igrp = proto_register_protocol("Cisco Interior Gateway Routing Protocol",
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"IGRP", "igrp");
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/* Required function calls to register the header fields and subtrees used */
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proto_register_field_array(proto_igrp, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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}
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void
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proto_reg_handoff_igrp(void)
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{
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dissector_handle_t igrp_handle;
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igrp_handle = create_dissector_handle(dissect_igrp, proto_igrp);
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dissector_add("ip.proto", IP_PROTO_IGRP, igrp_handle);
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}
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/* IGRP Packet structure:
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HEADER structure + k * VECTOR structure
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where: k = (Number of Interior routes) + (Number of System routes) + (Number of Exterior routes)
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HEADER structure is 12 bytes as follows :
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4 bits Version (only version 1 is defined)
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4 bits Opcode (1=Replay, 2=Request)
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8 bits Update Release
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16 bits Autonomous system number
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16 bits Number of Interior routes
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16 bits Number of System routes
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16 bits Number of Exterior routes
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16 bits Checksum
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-------
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12 bytes in header
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VECTOR structure is 14 bytes as follows :
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24 bits Network
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24 bits Delay
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24 bits Bandwidth
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16 bits MTU
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8 bits Reliability
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8 bits Load
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8 bits Hop count
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-------
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14 bytes in 1 vector
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It is interesting how is coded an ip network address in 3 bytes because IGRP is a classful routing protocol:
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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
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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
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If the Delay is 0xFFFFFF then the network is unreachable
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*/
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