/* packet-chdlc.c * Routines for Cisco HDLC packet disassembly * * $Id: packet-chdlc.c,v 1.21 2003/10/25 07:17:26 guy Exp $ * * Ethereal - 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include "etypes.h" #include "prefs.h" #include "chdlctypes.h" #include #include "packet-chdlc.h" #include "packet-ppp.h" #include "packet-ip.h" /* * See section 4.3.1 of RFC 1547, and * * http://www.nethelp.no/net/cisco-hdlc.txt */ static int proto_chdlc = -1; static int hf_chdlc_addr = -1; static int hf_chdlc_proto = -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_mysequence = -1; static int hf_slarp_yoursequence = -1; static gint ett_slarp = -1; static dissector_handle_t data_handle; /* * 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. * * Perhaps we should set up a protocol table for those protocols * that differ between Ethernet and Cisco HDLC, and have the PPP * code first try that table and, if it finds nothing in that * table, call "ethertype()". (Unfortunately, that means that - * assuming we had a Cisco SLARP dissector - said dissector were * disabled, SLARP packets would be dissected as Reverse ARP * packets, not as data.) */ #define CISCO_SLARP 0x8035 /* Cisco SLARP protocol */ static dissector_table_t subdissector_table; 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"}, {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} }; void capture_chdlc( const guchar *pd, int offset, int len, packet_counts *ld ) { if (!BYTES_ARE_IN_FRAME(offset, len, 4)) { ld->other++; return; } switch (pntohs(&pd[offset + 2])) { case ETHERTYPE_IP: capture_ip(pd, offset + 4, len, ld); break; default: ld->other++; break; } } void chdlctype(guint16 chdlctype, tvbuff_t *tvb, int offset_after_chdlctype, packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree, int chdlctype_id) { tvbuff_t *next_tvb; if (tree) { proto_tree_add_uint(fh_tree, chdlctype_id, tvb, offset_after_chdlctype - 2, 2, chdlctype); } next_tvb = tvb_new_subset(tvb, offset_after_chdlctype, -1, -1); /* do lookup with the subdissector table */ if (!dissector_try_port(subdissector_table, chdlctype, next_tvb, pinfo, tree)) { if (check_col(pinfo->cinfo, COL_PROTOCOL)) col_add_fstr(pinfo->cinfo, COL_PROTOCOL, "0x%04x", chdlctype); call_dissector(data_handle,next_tvb, pinfo, tree); } } static gint chdlc_fcs_decode = 0; /* 0 = No FCS, 1 = 16 bit FCS, 2 = 32 bit FCS */ static void dissect_chdlc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_item *ti; proto_tree *fh_tree = NULL; guint8 addr; guint16 proto; if (check_col(pinfo->cinfo, COL_PROTOCOL)) col_set_str(pinfo->cinfo, COL_PROTOCOL, "CHDLC"); if (check_col(pinfo->cinfo, COL_INFO)) col_clear(pinfo->cinfo, COL_INFO); switch (pinfo->p2p_dir) { case P2P_DIR_SENT: if (check_col(pinfo->cinfo, COL_RES_DL_SRC)) col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE"); if (check_col(pinfo->cinfo, COL_RES_DL_DST)) col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE"); break; case P2P_DIR_RECV: if (check_col(pinfo->cinfo, COL_RES_DL_SRC)) col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE"); if (check_col(pinfo->cinfo, COL_RES_DL_DST)) col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE"); break; default: if (check_col(pinfo->cinfo, COL_RES_DL_SRC)) col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "N/A"); if (check_col(pinfo->cinfo, COL_RES_DL_DST)) col_set_str(pinfo->cinfo, COL_RES_DL_DST, "N/A"); break; } addr = tvb_get_guint8(tvb, 0); proto = tvb_get_ntohs(tvb, 2); if (tree) { ti = proto_tree_add_item(tree, proto_chdlc, tvb, 0, 4, FALSE); fh_tree = proto_item_add_subtree(ti, ett_chdlc); proto_tree_add_uint(fh_tree, hf_chdlc_addr, tvb, 0, 1, addr); } decode_fcs(tvb, fh_tree, chdlc_fcs_decode, 2); chdlctype(proto, tvb, 4, pinfo, tree, fh_tree, hf_chdlc_proto); } 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, "", HFILL }}, { &hf_chdlc_proto, { "Protocol", "chdlc.protocol", FT_UINT16, BASE_HEX, VALS(chdlc_vals), 0x0, "", 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("chdlctype", "Cisco HDLC frame type", FT_UINT16, BASE_HEX); 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, FALSE); } void proto_reg_handoff_chdlc(void) { dissector_handle_t chdlc_handle; data_handle = find_dissector("data"); chdlc_handle = find_dissector("chdlc"); dissector_add("wtap_encap", WTAP_ENCAP_CHDLC, chdlc_handle); dissector_add("wtap_encap", WTAP_ENCAP_CHDLC_WITH_PHDR, chdlc_handle); } #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 void dissect_slarp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) { proto_item *ti; proto_tree *slarp_tree = NULL; guint32 code; guint32 address; guint32 mysequence; guint32 yoursequence; if (check_col(pinfo->cinfo, COL_PROTOCOL)) col_set_str(pinfo->cinfo, COL_PROTOCOL, "SLARP"); if (check_col(pinfo->cinfo, COL_INFO)) col_clear(pinfo->cinfo, COL_INFO); code = tvb_get_ntohl(tvb, 0); if (tree) { ti = proto_tree_add_item(tree, proto_slarp, tvb, 0, 14, FALSE); slarp_tree = proto_item_add_subtree(ti, ett_slarp); } switch (code) { case SLARP_REQUEST: case SLARP_REPLY: if (check_col(pinfo->cinfo, COL_INFO)) { tvb_memcpy(tvb, (guint8 *)&address, 4, 4); col_add_fstr(pinfo->cinfo, COL_INFO, "%s, from %s, mask %s", match_strval(code, slarp_ptype_vals), get_hostname(address), ip_to_str(tvb_get_ptr(tvb, 8, 4))); } 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, FALSE); proto_tree_add_text(slarp_tree, tvb, 8, 4, "Netmask: %s", ip_to_str(tvb_get_ptr(tvb, 8, 4))); } break; case SLARP_LINECHECK: mysequence = tvb_get_ntohl(tvb, 4); yoursequence = tvb_get_ntohl(tvb, 8); if (check_col(pinfo->cinfo, COL_INFO)) { col_add_fstr(pinfo->cinfo, COL_INFO, "%s, outgoing sequence %u, returned sequence %u", match_strval(code, slarp_ptype_vals), mysequence, yoursequence); } if (tree) { 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_mysequence, tvb, 8, 4, yoursequence); } break; default: if (check_col(pinfo->cinfo, COL_INFO)) col_add_fstr(pinfo->cinfo, COL_INFO, "Unknown packet type 0x%08X", code); if (tree) { proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code); call_dissector(data_handle, tvb_new_subset(tvb, 4, -1, -1), pinfo, slarp_tree); } break; } } void proto_register_slarp(void) { static hf_register_info hf[] = { { &hf_slarp_ptype, { "Packet type", "slarp.ptype", FT_UINT32, BASE_DEC, VALS(slarp_ptype_vals), 0x0, "", HFILL }}, { &hf_slarp_address, { "Address", "slarp.address", FT_IPv4, BASE_NONE, NULL, 0x0, "", HFILL }}, /* XXX - need an FT_ for netmasks, which is like FT_IPV4 but doesn't get translated to a host name. */ { &hf_slarp_mysequence, { "Outgoing sequence number", "slarp.mysequence", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }}, { &hf_slarp_yoursequence, { "Returned sequence number", "slarp.yoursequence", FT_UINT32, BASE_DEC, NULL, 0x0, "", HFILL }}, }; static gint *ett[] = { &ett_chdlc, &ett_slarp, }; 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)); } void proto_reg_handoff_slarp(void) { dissector_handle_t slarp_handle; slarp_handle = create_dissector_handle(dissect_slarp, proto_slarp); dissector_add("chdlctype", CISCO_SLARP, slarp_handle); }