2 * Routines for IGRP dissection
3 * Copyright 2000, Paul Ionescu <paul@acorp.ro>
7 * http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a00800c8ae1.shtml
11 * Wireshark - Network traffic analyzer
12 * By Gerald Combs <gerald@wireshark.org>
13 * Copyright 1998 Gerald Combs
15 * Copied from packet-syslog.c
17 * This program is free software; you can redistribute it and/or
18 * modify it under the terms of the GNU General Public License
19 * as published by the Free Software Foundation; either version 2
20 * of the License, or (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
27 * You should have received a copy of the GNU General Public License
28 * along with this program; if not, write to the Free Software
29 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
42 #include <epan/packet.h>
43 #include <epan/ipproto.h>
45 #define IGRP_HEADER_LENGTH 12
46 #define IGRP_ENTRY_LENGTH 14
48 static gint proto_igrp = -1;
49 static gint hf_igrp_update = -1;
50 static gint hf_igrp_as = -1;
52 static gint ett_igrp = -1;
53 static gint ett_igrp_vektor = -1;
54 static gint ett_igrp_net = -1;
56 static void dissect_vektor_igrp (tvbuff_t *tvb, proto_tree *igrp_vektor_tree, guint8 network);
58 static void dissect_igrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
60 guint8 ver_and_opcode,version,opcode,network;
61 gint offset=IGRP_HEADER_LENGTH;
62 guint16 ninterior,nsystem,nexterior;
65 proto_tree *igrp_tree, *igrp_vektor_tree;
68 col_set_str(pinfo->cinfo, COL_PROTOCOL, "IGRP");
69 if (check_col(pinfo->cinfo, COL_INFO))
70 col_clear(pinfo->cinfo, COL_INFO);
72 ver_and_opcode = tvb_get_guint8(tvb,0);
75 if (check_col(pinfo->cinfo, COL_INFO)) {
76 switch (ver_and_opcode) {
78 col_set_str(pinfo->cinfo, COL_INFO, "Response" );
81 col_set_str(pinfo->cinfo, COL_INFO, "Request" );
84 col_set_str(pinfo->cinfo, COL_INFO, "Unknown version or opcode");
92 ti = proto_tree_add_protocol_format(tree, proto_igrp, tvb, 0, -1,
95 igrp_tree = proto_item_add_subtree(ti, ett_igrp);
97 version = (ver_and_opcode&0xf0)>>4 ; /* version is the fist half of the byte */
98 opcode = ver_and_opcode&0x0f ; /* opcode is the last half of the byte */
100 proto_tree_add_text(igrp_tree, tvb, 0,1,"IGRP Version : %d %s",version,(version==1?" ":" - Unknown Version, The dissection may be inaccurate"));
101 proto_tree_add_text(igrp_tree, tvb, 0,1,"Command : %d %s",opcode,(opcode==1?"(Response)":"(Request)"));
102 proto_tree_add_item(igrp_tree, hf_igrp_update, tvb, 1,1, FALSE);
103 proto_tree_add_item(igrp_tree, hf_igrp_as, tvb, 2,2, FALSE);
105 ninterior = tvb_get_ntohs(tvb,4);
106 nsystem = tvb_get_ntohs(tvb,6);
107 nexterior = tvb_get_ntohs(tvb,8);
109 /* this is a ugly hack to find the first byte of the IP source address */
110 if (pinfo->net_src.type == AT_IPv4) {
111 ipsrc = pinfo->net_src.data;
114 network = 0; /* XXX - shouldn't happen */
116 ti = proto_tree_add_text(igrp_tree, tvb, 4,2,"Interior routes : %d",ninterior);
117 for( ; ninterior>0 ; ninterior-- ) {
118 igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_vektor);
119 next_tvb = tvb_new_subset(tvb, offset, IGRP_ENTRY_LENGTH, -1);
120 dissect_vektor_igrp (next_tvb,igrp_vektor_tree,network);
121 offset+=IGRP_ENTRY_LENGTH;
124 ti = proto_tree_add_text(igrp_tree, tvb, 6,2,"System routes : %d",nsystem);
125 for( ; nsystem>0 ; nsystem-- ) {
126 igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_vektor);
127 next_tvb = tvb_new_subset(tvb, offset, IGRP_ENTRY_LENGTH, -1);
128 dissect_vektor_igrp (next_tvb,igrp_vektor_tree,0);
129 offset+=IGRP_ENTRY_LENGTH;
132 ti = proto_tree_add_text(igrp_tree, tvb, 8,2,"Exterior routes : %d",nexterior);
133 for( ; nexterior>0 ; nexterior-- ) {
134 igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_vektor);
135 next_tvb = tvb_new_subset(tvb, offset, IGRP_ENTRY_LENGTH, -1);
136 dissect_vektor_igrp (next_tvb,igrp_vektor_tree,0);
137 offset+=IGRP_ENTRY_LENGTH;
140 proto_tree_add_text(igrp_tree, tvb, 10,2,"Checksum = 0x%4x",tvb_get_ntohs(tvb,10));
144 static void dissect_vektor_igrp (tvbuff_t *tvb, proto_tree *igrp_vektor_tree, guint8 network)
147 guint8 *ptr_addr,addr[5];
150 addr[1]=tvb_get_guint8(tvb,0);
151 addr[2]=tvb_get_guint8(tvb,1);
152 addr[3]=tvb_get_guint8(tvb,2);
156 if (network==0) ptr_addr=&addr[1];
158 ti = proto_tree_add_text (igrp_vektor_tree, tvb, 0 ,14,
159 "Entry for network %s", ip_to_str(ptr_addr)) ;
160 igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_net);
161 proto_tree_add_text (igrp_vektor_tree, tvb, 0 ,3,"Network = %s",ip_to_str(ptr_addr)) ;
162 proto_tree_add_text (igrp_vektor_tree, tvb, 3 ,3,"Delay = %d",tvb_get_ntoh24(tvb,3)) ;
163 proto_tree_add_text (igrp_vektor_tree, tvb, 6 ,3,"Bandwidth = %d",tvb_get_ntoh24(tvb,6)) ;
164 proto_tree_add_text (igrp_vektor_tree, tvb, 9 ,2,"MTU = %d bytes",tvb_get_ntohs(tvb,9)) ;
165 proto_tree_add_text (igrp_vektor_tree, tvb, 11,1,"Reliability = %d",tvb_get_guint8(tvb,11)) ;
166 proto_tree_add_text (igrp_vektor_tree, tvb, 12,1,"Load = %d",tvb_get_guint8(tvb,12)) ;
167 proto_tree_add_text (igrp_vektor_tree, tvb, 13,1,"Hop count = %d hops",tvb_get_guint8(tvb,13)) ;
171 /* Register the protocol with Wireshark */
172 void proto_register_igrp(void)
175 /* Setup list of header fields */
176 static hf_register_info hf[] = {
179 { "Update Release", "igrp.update",
180 FT_UINT8, BASE_DEC, NULL, 0x0 ,
181 "Update Release number", HFILL }
184 { "Autonomous System", "igrp.as",
185 FT_UINT16, BASE_DEC, NULL, 0x0 ,
186 "Autonomous System number", HFILL }
190 /* Setup protocol subtree array */
191 static gint *ett[] = {
197 /* Register the protocol name and description */
198 proto_igrp = proto_register_protocol("Cisco Interior Gateway Routing Protocol",
201 /* Required function calls to register the header fields and subtrees used */
202 proto_register_field_array(proto_igrp, hf, array_length(hf));
203 proto_register_subtree_array(ett, array_length(ett));
207 proto_reg_handoff_igrp(void)
209 dissector_handle_t igrp_handle;
211 igrp_handle = create_dissector_handle(dissect_igrp, proto_igrp);
212 dissector_add("ip.proto", IP_PROTO_IGRP, igrp_handle);
215 /* IGRP Packet structure:
217 HEADER structure + k * VECTOR structure
218 where: k = (Number of Interior routes) + (Number of System routes) + (Number of Exterior routes)
220 HEADER structure is 12 bytes as follows :
222 4 bits Version (only version 1 is defined)
223 4 bits Opcode (1=Replay, 2=Request)
224 8 bits Update Release
225 16 bits Autonomous system number
226 16 bits Number of Interior routes
227 16 bits Number of System routes
228 16 bits Number of Exterior routes
233 VECTOR structure is 14 bytes as follows :
244 It is interesting how is coded an ip network address in 3 bytes because IGRP is a classful routing protocol:
245 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
246 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
248 If the Delay is 0xFFFFFF then the network is unreachable