/* packet-igrp.c * Routines for IGRP dissection * Copyright 2000, Paul Ionescu * * $Id: packet-igrp.c,v 1.14 2003/12/21 05:51:33 jmayer Exp $ * * Ethereal - Network traffic analyzer * By Gerald Combs * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include #include #include #include "ipproto.h" #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; static gint ett_igrp = -1; static gint ett_igrp_vektor = -1; static gint ett_igrp_net = -1; static void dissect_vektor_igrp (tvbuff_t *tvb, proto_tree *igrp_vektor_tree, guint8 network); static void dissect_igrp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { guint8 ver_and_opcode,version,opcode,update,network; gint offset=IGRP_HEADER_LENGTH; guint16 as,net1,net2,net3; proto_item *ti; proto_tree *igrp_tree, *igrp_vektor_tree; tvbuff_t *next_tvb; if (check_col(pinfo->cinfo, COL_PROTOCOL)) col_set_str(pinfo->cinfo, COL_PROTOCOL, "IGRP"); if (check_col(pinfo->cinfo, COL_INFO)) col_clear(pinfo->cinfo, COL_INFO); ver_and_opcode = tvb_get_guint8(tvb,0); update = tvb_get_guint8(tvb,1); as = tvb_get_ntohs(tvb,2); if (check_col(pinfo->cinfo, COL_INFO)) { switch (ver_and_opcode) { case 0x11: col_add_fstr(pinfo->cinfo, COL_INFO, "Response" ); break; case 0x12: col_add_fstr(pinfo->cinfo, COL_INFO, "Request" ); break; default: col_add_fstr(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 */ proto_tree_add_text(igrp_tree, tvb, 0,1,"IGRP Version : %d %s",version,(version==1?" ":" - Unknown Version, The dissection may be innacurate")); proto_tree_add_text(igrp_tree, tvb, 0,1,"Command : %d %s",opcode,(opcode==1?"(Response)":"(Request)")); proto_tree_add_uint(igrp_tree, hf_igrp_update, tvb, 1,1, update); proto_tree_add_uint(igrp_tree, hf_igrp_as, tvb, 2,2,as); net1 = tvb_get_ntohs(tvb,4); net2 = tvb_get_ntohs(tvb,6); net3 = tvb_get_ntohs(tvb,8); /* this is a ugly hack to find the first byte of the IP source address */ network = pinfo->net_src.data[0]; ti = proto_tree_add_text(igrp_tree, tvb, 4,2,"Interior routes : %d",net1); for( ; net1>0 ; net1-- ) { 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_text(igrp_tree, tvb, 6,2,"System routes : %d",net2); for( ; net2>0 ; net2-- ) { 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_text(igrp_tree, tvb, 8,2,"Exterior routes : %d",net3); for( ; net3>0 ; net3-- ) { 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_text(igrp_tree, tvb, 10,2,"Checksum = 0x%4x",tvb_get_ntohs(tvb,10)); } return; } static void dissect_vektor_igrp (tvbuff_t *tvb, proto_tree *igrp_vektor_tree, guint8 network) { proto_item *ti; guint8 *ptr_addr,addr[5]; addr[0]=network; addr[1]=tvb_get_guint8(tvb,0); addr[2]=tvb_get_guint8(tvb,1); addr[3]=tvb_get_guint8(tvb,2); addr[4]=0; ptr_addr=addr; if (network==0) ptr_addr=&addr[1]; ti = proto_tree_add_text (igrp_vektor_tree, tvb, 0 ,14, "Entry for network %s", ip_to_str(ptr_addr)) ; igrp_vektor_tree = proto_item_add_subtree(ti,ett_igrp_net); proto_tree_add_text (igrp_vektor_tree, tvb, 0 ,3,"Network = %s",ip_to_str(ptr_addr)) ; proto_tree_add_text (igrp_vektor_tree, tvb, 3 ,3,"Delay = %d",tvb_get_ntoh24(tvb,3)) ; proto_tree_add_text (igrp_vektor_tree, tvb, 6 ,3,"Bandwidth = %d",tvb_get_ntoh24(tvb,6)) ; proto_tree_add_text (igrp_vektor_tree, tvb, 9 ,2,"MTU = %d bytes",tvb_get_ntohs(tvb,9)) ; proto_tree_add_text (igrp_vektor_tree, tvb, 11,1,"Reliability = %d",tvb_get_guint8(tvb,11)) ; proto_tree_add_text (igrp_vektor_tree, tvb, 12,1,"Load = %d",tvb_get_guint8(tvb,12)) ; proto_tree_add_text (igrp_vektor_tree, tvb, 13,1,"Hop count = %d hops",tvb_get_guint8(tvb,13)) ; } /* Register the protocol with Ethereal */ 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 } } }; /* Setup protocol subtree array */ static gint *ett[] = { &ett_igrp, &ett_igrp_vektor, &ett_igrp_net }; /* 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)); } void proto_reg_handoff_igrp(void) { dissector_handle_t igrp_handle; igrp_handle = create_dissector_handle(dissect_igrp, proto_igrp); dissector_add("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 */