/* packet-carp.c * Routines for the Common Address Redundancy Protocol (CARP) * Copyright 2013, Uli Heilmeier * Based on packet-vrrp.c by Heikki Vatiainen * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * 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 #include #include #include void proto_register_carp(void); void proto_reg_handoff_carp(void); static gint proto_carp = -1; static gint ett_carp = -1; static gint ett_carp_ver_type = -1; static gint hf_carp_ver_type = -1; static gint hf_carp_version = -1; static gint hf_carp_type = -1; static gint hf_carp_vhid = -1; static gint hf_carp_advskew = -1; static gint hf_carp_authlen = -1; static gint hf_carp_demotion = -1; static gint hf_carp_advbase = -1; static gint hf_carp_counter = -1; static gint hf_carp_hmac = -1; static gint hf_carp_checksum = -1; static gint hf_carp_checksum_status = -1; static expert_field ei_carp_checksum = EI_INIT; #define CARP_VERSION_MASK 0xf0 #define CARP_TYPE_MASK 0x0f #define CARP_TYPE_ADVERTISEMENT 1 static const value_string carp_type_vals[] = { {CARP_TYPE_ADVERTISEMENT, "Advertisement"}, {0, NULL} }; static gboolean test_carp_packet(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree _U_, void *data _U_) { guint8 ver_type, version, auth_length; /* First some simple check if the data is really CARP */ if (tvb_captured_length(tvb) < 36) return FALSE; /* Version must be 1 or 2, type must be in carp_type_vals */ ver_type = tvb_get_guint8(tvb, 0); version = hi_nibble(ver_type); if ((version == 0) || (version > 2) || (try_val_to_str(lo_nibble(ver_type), carp_type_vals) == NULL)) return FALSE; auth_length = tvb_get_guint8(tvb, 3); if ( auth_length != 7 ) return FALSE; return TRUE; } static int dissect_carp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) { int offset = 0; guint carp_len; guint8 vhid; vec_t cksum_vec[4]; proto_item *ti, *tv; proto_tree *carp_tree, *ver_type_tree; guint8 ver_type; /* Make sure it's a CARP packet */ if (!test_carp_packet(tvb, pinfo, tree, data)) return 0; col_set_str(pinfo->cinfo, COL_PROTOCOL, "CARP"); col_clear(pinfo->cinfo, COL_INFO); vhid = tvb_get_guint8(tvb, 1); col_add_fstr(pinfo->cinfo, COL_INFO, "%s (Virtual Host ID: %u)", "Announcement", vhid); ti = proto_tree_add_item(tree, proto_carp, tvb, 0, -1, ENC_NA); carp_tree = proto_item_add_subtree(ti, ett_carp); ver_type = tvb_get_guint8(tvb, 0); tv = proto_tree_add_uint_format(carp_tree, hf_carp_ver_type, tvb, offset, 1, ver_type, "Version %u, Packet type %u (%s)", hi_nibble(ver_type), lo_nibble(ver_type), val_to_str_const(lo_nibble(ver_type), carp_type_vals, "Unknown")); ver_type_tree = proto_item_add_subtree(tv, ett_carp_ver_type); proto_tree_add_uint(ver_type_tree, hf_carp_version, tvb, offset, 1, ver_type); proto_tree_add_uint(ver_type_tree, hf_carp_type, tvb, offset, 1, ver_type); offset++; proto_tree_add_item(carp_tree, hf_carp_vhid, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(carp_tree, hf_carp_advskew, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(carp_tree, hf_carp_authlen, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(carp_tree, hf_carp_demotion, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(carp_tree, hf_carp_advbase, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; carp_len = tvb_reported_length(tvb); if (!pinfo->fragmented && tvb_captured_length(tvb) >= carp_len) { /* The packet isn't part of a fragmented datagram and isn't truncated, so we can checksum it. */ SET_CKSUM_VEC_TVB(cksum_vec[0], tvb, 0, carp_len); proto_tree_add_checksum(carp_tree, tvb, offset, hf_carp_checksum, hf_carp_checksum_status, &ei_carp_checksum, pinfo, in_cksum(&cksum_vec[0], 1), ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_IN_CKSUM); } else { proto_tree_add_checksum(carp_tree, tvb, offset, hf_carp_checksum, hf_carp_checksum_status, &ei_carp_checksum, pinfo, 0, ENC_BIG_ENDIAN, PROTO_CHECKSUM_NO_FLAGS); } offset+=2; /* Counter */ proto_tree_add_item(carp_tree, hf_carp_counter, tvb, offset, 8, ENC_BIG_ENDIAN); offset+=8; proto_tree_add_item(carp_tree, hf_carp_hmac, tvb, offset, 20, ENC_NA); offset+=20; return offset; } /* heuristic dissector */ static gboolean dissect_carp_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) { if (!test_carp_packet(tvb, pinfo, tree, data)) return FALSE; dissect_carp(tvb, pinfo, tree, data); return TRUE; } void proto_register_carp(void) { static hf_register_info hf[] = { { &hf_carp_ver_type, {"CARP message version and type", "carp.typever", FT_UINT8, BASE_DEC, NULL, 0x0, "CARP version and type", HFILL }}, { &hf_carp_version, {"CARP protocol version", "carp.version", FT_UINT8, BASE_DEC, NULL, CARP_VERSION_MASK, "CARP version", HFILL }}, { &hf_carp_type, {"CARP packet type", "carp.type", FT_UINT8, BASE_DEC, VALS(carp_type_vals), CARP_TYPE_MASK, "CARP type", HFILL }}, { &hf_carp_vhid, {"Virtual Host ID", "carp.vhid", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }}, { &hf_carp_advskew, {"Advertisement Skew", "carp.advskew", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }}, { &hf_carp_authlen, {"Auth Len", "carp.authlen", FT_UINT8, BASE_DEC, NULL, 0x0, "Size of counter+hash in 32bit chunks", HFILL }}, { &hf_carp_demotion, {"Demotion indicator", "carp.demotion", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }}, { &hf_carp_advbase, {"Adver Int", "carp.adver_int", FT_UINT8, BASE_DEC, NULL, 0x0, "Time interval (in seconds) between ADVERTISEMENTS", HFILL }}, { &hf_carp_counter, {"Counter", "carp.counter", FT_UINT64, BASE_DEC, NULL, 0x0, NULL, HFILL }}, { &hf_carp_hmac, {"HMAC", "carp.hmac", FT_BYTES, BASE_NONE, NULL, 0x0, "SHA-1 HMAC", HFILL }}, { &hf_carp_checksum, {"Checksum", "carp.checksum", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL }}, { &hf_carp_checksum_status, {"Checksum Status", "carp.checksum.status", FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x0, NULL, HFILL }}, }; static gint *ett[] = { &ett_carp, &ett_carp_ver_type }; static ei_register_info ei[] = { { &ei_carp_checksum, { "carp.bad_checksum", PI_CHECKSUM, PI_ERROR, "Bad checksum", EXPFILL }}, }; expert_module_t* expert_carp; proto_carp = proto_register_protocol("Common Address Redundancy Protocol", "CARP", "carp"); proto_register_field_array(proto_carp, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); expert_carp = expert_register_protocol(proto_carp); expert_register_field_array(expert_carp, ei, array_length(ei)); } void proto_reg_handoff_carp(void) { dissector_handle_t carp_handle; carp_handle = create_dissector_handle(dissect_carp, proto_carp); dissector_add_uint("ip.proto", IP_PROTO_VRRP, carp_handle); heur_dissector_add( "ip", dissect_carp_heur, "CARP over IP", "carp_ip", proto_carp, HEURISTIC_ENABLE); } /* * Editor modelines - http://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 4 * tab-width: 8 * indent-tabs-mode: nil * End: * * vi: set shiftwidth=4 tabstop=8 expandtab: * :indentSize=4:tabSize=8:noTabs=true: */