![Guy Harris](/assets/img/avatar_default.png)
statements. Move the setting of the Protocol column in various dissectors before anything is fetched from the packet, and also clear the Info column at that point in those and some other dissectors, so that if an exception is thrown, the columns don't reflect the previous protocol. Make the IP dissector static, as it's called only via dissector tables or dissector handles. Also make the "dissect the TOS field as the DiffServ DS field" flag static, as it's not referred to outside of "packet-ip.c". In the NCP dissector, refer to the port type through "pinfo" rather than through the global "pi", as it's a tvbuffified dissector. svn path=/trunk/; revision=2929
247 lines
7.8 KiB
C
247 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 1.5 2001/01/22 03:33:45 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@zing.org>
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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 "packet.h"
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#define IP_PROTO_IGRP 9
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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->fd, COL_PROTOCOL))
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col_set_str(pinfo->fd, COL_PROTOCOL, "IGRP");
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if (check_col(pinfo->fd, COL_INFO))
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col_clear(pinfo->fd, 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->fd, COL_INFO)) {
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switch (ver_and_opcode) {
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case 0x11:
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col_add_fstr(pinfo->fd, COL_INFO, "Response" );
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break;
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case 0x12:
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col_add_fstr(pinfo->fd, COL_INFO, "Request" );
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break;
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default:
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col_add_fstr(pinfo->fd, 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,
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tvb_length(tvb), "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" },
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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" }
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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_add("ip.proto", IP_PROTO_IGRP, dissect_igrp, proto_igrp);
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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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