/* packet-chdlc.c * Routines for Cisco HDLC packet disassembly * * 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 #include #include #include #include #include "packet-chdlc.h" #include "packet-ppp.h" #include "packet-ip.h" #include "packet-juniper.h" #include "packet-l2tp.h" #include /* * See section 4.3.1 of RFC 1547, and * * http://www.nethelp.no/net/cisco-hdlc.txt */ void proto_register_chdlc(void); void proto_reg_handoff_chdlc(void); void proto_register_slarp(void); void proto_reg_handoff_slarp(void); static int proto_chdlc = -1; static int hf_chdlc_addr = -1; static int hf_chdlc_control = -1; static int hf_chdlc_proto = -1; static int hf_chdlc_clns_padding = -1; static gint ett_chdlc = -1; static int proto_slarp = -1; static int hf_slarp_ptype = -1; static int hf_slarp_address = -1; static int hf_slarp_netmask = -1; static int hf_slarp_mysequence = -1; static int hf_slarp_yoursequence = -1; static int hf_slarp_reliability = -1; static expert_field ei_slarp_reliability = EI_INIT; static gint ett_slarp = -1; /* * Protocol types for the Cisco HDLC format. * * As per the above, according to RFC 1547, these are "standard 16 bit * Ethernet protocol type code[s]", but 0x8035 is Reverse ARP, and * that is (at least according to the Linux ISDN code) not the * same as Cisco SLARP. * * In addition, 0x2000 is apparently the Cisco Discovery Protocol, but * on Ethernet those are encapsulated inside SNAP with an OUI of * OUI_CISCO, not OUI_ENCAP_ETHER. * * We thus have a separate dissector table for Cisco HDLC types. * We could perhaps have that table hold only type values that * wouldn't be in the Ethernet dissector table, and check that * table first and the Ethernet dissector table if that fails. */ #define CISCO_SLARP 0x8035 /* Cisco SLARP protocol */ static dissector_table_t subdissector_table; static dissector_handle_t chdlc_handle; static capture_dissector_handle_t ip_cap_handle; static const value_string chdlc_address_vals[] = { {CHDLC_ADDR_UNICAST, "Unicast"}, {CHDLC_ADDR_MULTICAST, "Multicast"}, {0, NULL} }; const value_string chdlc_vals[] = { {0x2000, "Cisco Discovery Protocol"}, {ETHERTYPE_IP, "IP"}, {ETHERTYPE_IPv6, "IPv6"}, {CISCO_SLARP, "SLARP"}, {ETHERTYPE_DEC_LB, "DEC LanBridge"}, {CHDLCTYPE_BPDU, "Spanning Tree BPDU"}, {ETHERTYPE_ATALK, "Appletalk"}, {ETHERTYPE_AARP, "AARP"}, {ETHERTYPE_IPX, "Netware IPX/SPX"}, {ETHERTYPE_ETHBRIDGE, "Transparent Ethernet bridging" }, {CHDLCTYPE_OSI, "OSI" }, {ETHERTYPE_MPLS, "MPLS unicast"}, {ETHERTYPE_MPLS_MULTI, "MPLS multicast"}, {0, NULL} }; static gboolean capture_chdlc( const guchar *pd, int offset, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header) { if (!BYTES_ARE_IN_FRAME(offset, len, 4)) return FALSE; switch (pntoh16(&pd[offset + 2])) { case ETHERTYPE_IP: return call_capture_dissector(ip_cap_handle, pd, offset + 4, len, cpinfo, pseudo_header); } return FALSE; } void chdlctype(guint16 chdlc_type, tvbuff_t *tvb, int offset_after_chdlctype, packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree, int chdlctype_id) { tvbuff_t *next_tvb; int padbyte; proto_tree_add_uint(fh_tree, chdlctype_id, tvb, offset_after_chdlctype - 2, 2, chdlc_type); padbyte = tvb_get_guint8(tvb, offset_after_chdlctype); if (chdlc_type == CHDLCTYPE_OSI && !( padbyte == NLPID_ISO8473_CLNP || /* older Juniper SW does not send a padbyte */ padbyte == NLPID_ISO9542_ESIS || padbyte == NLPID_ISO10589_ISIS)) { /* There is a Padding Byte for CLNS protocols over Cisco HDLC */ proto_tree_add_item(fh_tree, hf_chdlc_clns_padding, tvb, offset_after_chdlctype, 1, ENC_BIG_ENDIAN); next_tvb = tvb_new_subset_remaining(tvb, offset_after_chdlctype + 1); } else { next_tvb = tvb_new_subset_remaining(tvb, offset_after_chdlctype); } /* do lookup with the subdissector table */ if (!dissector_try_uint(subdissector_table, chdlc_type, next_tvb, pinfo, tree)) { col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x", chdlc_type); call_data_dissector(next_tvb, pinfo, tree); } } static gint chdlc_fcs_decode = 0; /* 0 = No FCS, 1 = 16 bit FCS, 2 = 32 bit FCS */ static int dissect_chdlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { proto_item *ti; proto_tree *fh_tree = NULL; guint16 proto; col_set_str(pinfo->cinfo, COL_PROTOCOL, "CHDLC"); col_clear(pinfo->cinfo, COL_INFO); switch (pinfo->p2p_dir) { case P2P_DIR_SENT: col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE"); col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE"); break; case P2P_DIR_RECV: col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE"); col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE"); break; default: col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A"); col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A"); break; } proto = tvb_get_ntohs(tvb, 2); if (tree) { ti = proto_tree_add_item(tree, proto_chdlc, tvb, 0, 4, ENC_NA); fh_tree = proto_item_add_subtree(ti, ett_chdlc); proto_tree_add_item(fh_tree, hf_chdlc_addr, tvb, 0, 1, ENC_NA); proto_tree_add_item(fh_tree, hf_chdlc_control, tvb, 1, 1, ENC_NA); } decode_fcs(tvb, pinfo, fh_tree, chdlc_fcs_decode, 2); chdlctype(proto, tvb, 4, pinfo, tree, fh_tree, hf_chdlc_proto); return tvb_captured_length(tvb); } void proto_register_chdlc(void) { static hf_register_info hf[] = { { &hf_chdlc_addr, { "Address", "chdlc.address", FT_UINT8, BASE_HEX, VALS(chdlc_address_vals), 0x0, NULL, HFILL }}, { &hf_chdlc_control, { "Control", "chdlc.control", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }}, { &hf_chdlc_proto, { "Protocol", "chdlc.protocol", FT_UINT16, BASE_HEX, VALS(chdlc_vals), 0x0, NULL, HFILL }}, { &hf_chdlc_clns_padding, { "CLNS Padding", "chdlc.clns_padding", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }}, }; static gint *ett[] = { &ett_chdlc, }; module_t *chdlc_module; proto_chdlc = proto_register_protocol("Cisco HDLC", "CHDLC", "chdlc"); proto_register_field_array(proto_chdlc, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); /* subdissector code */ subdissector_table = register_dissector_table("chdlc.protocol", "Cisco HDLC protocol", proto_chdlc, FT_UINT16, BASE_HEX); chdlc_handle = register_dissector("chdlc", dissect_chdlc, proto_chdlc); /* Register the preferences for the chdlc protocol */ chdlc_module = prefs_register_protocol(proto_chdlc, NULL); prefs_register_enum_preference(chdlc_module, "fcs_type", "CHDLC Frame Checksum Type", "The type of CHDLC frame checksum (none, 16-bit, 32-bit)", &chdlc_fcs_decode, fcs_options, ENC_BIG_ENDIAN); register_capture_dissector("chdlc", capture_chdlc, proto_chdlc); } void proto_reg_handoff_chdlc(void) { capture_dissector_handle_t chdlc_cap_handle; dissector_add_uint("wtap_encap", WTAP_ENCAP_CHDLC, chdlc_handle); dissector_add_uint("wtap_encap", WTAP_ENCAP_CHDLC_WITH_PHDR, chdlc_handle); dissector_add_uint("juniper.proto", JUNIPER_PROTO_CHDLC, chdlc_handle); dissector_add_uint("l2tp.pw_type", L2TPv3_PROTOCOL_CHDLC, chdlc_handle); chdlc_cap_handle = find_capture_dissector("chdlc"); capture_dissector_add_uint("wtap_encap", WTAP_ENCAP_CHDLC, chdlc_cap_handle); ip_cap_handle = find_capture_dissector("ip"); } #define SLARP_REQUEST 0 #define SLARP_REPLY 1 #define SLARP_LINECHECK 2 static const value_string slarp_ptype_vals[] = { {SLARP_REQUEST, "Request"}, {SLARP_REPLY, "Reply"}, {SLARP_LINECHECK, "Line keepalive"}, {0, NULL} }; static int dissect_slarp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { proto_item *ti; proto_tree *slarp_tree; guint32 code; guint32 addr; guint32 mysequence; guint32 yoursequence; proto_item* reliability_item; col_set_str(pinfo->cinfo, COL_PROTOCOL, "SLARP"); col_clear(pinfo->cinfo, COL_INFO); code = tvb_get_ntohl(tvb, 0); ti = proto_tree_add_item(tree, proto_slarp, tvb, 0, 14, ENC_NA); slarp_tree = proto_item_add_subtree(ti, ett_slarp); switch (code) { case SLARP_REQUEST: case SLARP_REPLY: addr = tvb_get_ipv4(tvb, 4); col_add_fstr(pinfo->cinfo, COL_INFO, "%s, from %s, mask %s", val_to_str(code, slarp_ptype_vals, "Unknown (%d)"), get_hostname(addr), tvb_ip_to_str(tvb, 8)); if (tree) { proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code); proto_tree_add_item(slarp_tree, hf_slarp_address, tvb, 4, 4, ENC_BIG_ENDIAN); proto_tree_add_item(slarp_tree, hf_slarp_netmask, tvb, 8, 4, ENC_BIG_ENDIAN); } break; case SLARP_LINECHECK: mysequence = tvb_get_ntohl(tvb, 4); yoursequence = tvb_get_ntohl(tvb, 8); col_add_fstr(pinfo->cinfo, COL_INFO, "%s, outgoing sequence %u, returned sequence %u", val_to_str(code, slarp_ptype_vals, "Unknown (%d)"), mysequence, yoursequence); proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code); proto_tree_add_uint(slarp_tree, hf_slarp_mysequence, tvb, 4, 4, mysequence); proto_tree_add_uint(slarp_tree, hf_slarp_yoursequence, tvb, 8, 4, yoursequence); reliability_item = proto_tree_add_item(slarp_tree, hf_slarp_reliability, tvb, 12, 2, ENC_BIG_ENDIAN); if (tvb_get_ntohs(tvb, 12) != 0xFFFF) { expert_add_info(pinfo, reliability_item, &ei_slarp_reliability); } break; default: col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown packet type 0x%08X", code); proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code); call_data_dissector(tvb_new_subset_remaining(tvb, 4), pinfo, slarp_tree); break; } return tvb_captured_length(tvb); } void proto_register_slarp(void) { expert_module_t* expert_slarp; static hf_register_info hf[] = { { &hf_slarp_ptype, { "Packet type", "slarp.ptype", FT_UINT32, BASE_DEC, VALS(slarp_ptype_vals), 0x0, NULL, HFILL }}, { &hf_slarp_address, { "Address", "slarp.address", FT_IPv4, BASE_NONE, NULL, 0x0, NULL, HFILL }}, /* XXX - need an FT_ for netmasks, which is like FT_IPV4 but doesn't get translated to a host name. */ { &hf_slarp_netmask, { "Netmask", "slarp.netmask", FT_IPv4, BASE_NETMASK, NULL, 0x0, NULL, HFILL }}, { &hf_slarp_mysequence, { "Outgoing sequence number", "slarp.mysequence", FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL }}, { &hf_slarp_yoursequence, { "Returned sequence number", "slarp.yoursequence", FT_UINT32, BASE_DEC, NULL, 0x0, NULL, HFILL }}, { &hf_slarp_reliability, { "Reliability", "slarp.reliability", FT_UINT16, BASE_HEX, NULL, 0x0, NULL, HFILL }}, }; static gint *ett[] = { &ett_slarp, }; static ei_register_info ei[] = { { &ei_slarp_reliability, { "slarp.reliability.invalid", PI_MALFORMED, PI_ERROR, "Reliability must be 0xFFFF", EXPFILL }} }; proto_slarp = proto_register_protocol("Cisco SLARP", "SLARP", "slarp"); proto_register_field_array(proto_slarp, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); expert_slarp = expert_register_protocol(proto_slarp); expert_register_field_array(expert_slarp, ei, array_length(ei)); } void proto_reg_handoff_slarp(void) { dissector_handle_t slarp_handle; slarp_handle = create_dissector_handle(dissect_slarp, proto_slarp); dissector_add_uint("chdlc.protocol", CISCO_SLARP, slarp_handle); } /* * Editor modelines - http://www.wireshark.org/tools/modelines.html * * Local Variables: * c-basic-offset: 2 * tab-width: 8 * indent-tabs-mode: nil * End: * * ex: set shiftwidth=2 tabstop=8 expandtab: * :indentSize=2:tabSize=8:noTabs=true: */