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Diffstat (limited to 'packet-chdlc.c')
| -rw-r--r-- | packet-chdlc.c | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/packet-chdlc.c b/packet-chdlc.c new file mode 100644 index 0000000000..7c5d6d64aa --- /dev/null +++ b/packet-chdlc.c @@ -0,0 +1,306 @@ +/* packet-chdlc.c + * Routines for Cisco HDLC packet disassembly + * + * $Id: packet-chdlc.c,v 1.1 2001/03/15 09:11:00 guy Exp $ + * + * Ethereal - Network traffic analyzer + * By Gerald Combs <gerald@zing.org> + * + * 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 + +#ifdef HAVE_SYS_TYPES_H +# include <sys/types.h> +#endif + +#include <glib.h> +#include "packet.h" +#include "etypes.h" +#include "resolv.h" +#include "packet-chdlc.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; + +/* + * 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"}, + {ETHERTYPE_ATALK, "Appletalk"}, + {ETHERTYPE_AARP, "AARP"}, + {ETHERTYPE_IPX, "Netware IPX/SPX"}, + {0, NULL} +}; + +void +capture_chdlc( const u_char *pd, int offset, packet_counts *ld ) { + switch (pntohs(&pd[offset + 2])) { + case ETHERTYPE_IP: + capture_ip(pd, offset + 4, 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->fd, COL_PROTOCOL)) + col_add_fstr(pinfo->fd, COL_PROTOCOL, "0x%04x", chdlctype); + dissect_data(next_tvb, 0, pinfo, tree); + } +} + +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->fd, COL_RES_DL_SRC)) + col_set_str(pinfo->fd, COL_RES_DL_SRC, "N/A"); + if (check_col(pinfo->fd, COL_RES_DL_DST)) + col_set_str(pinfo->fd, COL_RES_DL_DST, "N/A"); + if (check_col(pinfo->fd, COL_PROTOCOL)) + col_set_str(pinfo->fd, COL_PROTOCOL, "CHDLC"); + if (check_col(pinfo->fd, COL_INFO)) + col_clear(pinfo->fd, COL_INFO); + + 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); + } + + 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, "" }}, + { &hf_chdlc_proto, + { "Protocol", "chdlc.protocol", FT_UINT16, BASE_HEX, + VALS(chdlc_vals), 0x0, "" }}, + }; + static gint *ett[] = { + &ett_chdlc, + }; + + 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"); + + register_dissector("chdlc", dissect_chdlc, proto_chdlc); +} + +void +proto_reg_handoff_chdlc(void) +{ + dissector_add("wtap_encap", WTAP_ENCAP_CHDLC, dissect_chdlc, proto_chdlc); +} + +#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 mysequence; + guint32 yoursequence; + + if (check_col(pinfo->fd, COL_PROTOCOL)) + col_set_str(pinfo->fd, COL_PROTOCOL, "SLARP"); + if (check_col(pinfo->fd, COL_INFO)) + col_clear(pinfo->fd, 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->fd, COL_INFO)) { + col_add_fstr(pinfo->fd, COL_INFO, "%s, from %s, mask %s", + match_strval(code, slarp_ptype_vals), + get_hostname(tvb_get_ntohl(tvb, 4)), + 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->fd, COL_INFO)) { + col_add_fstr(pinfo->fd, 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->fd, COL_INFO)) + col_add_fstr(pinfo->fd, COL_INFO, "Unknown packet type 0x%08X", code); + if (tree) { + proto_tree_add_uint(slarp_tree, hf_slarp_ptype, tvb, 0, 4, code); + dissect_data(tvb, 4, 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, "" }}, + { &hf_slarp_address, + { "Address", "slarp.address", FT_IPv4, BASE_NONE, + NULL, 0x0, "" }}, + /* 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, "" }}, + { &hf_slarp_yoursequence, + { "Returned sequence number", "slarp.yoursequence", FT_UINT32, BASE_DEC, + NULL, 0x0, "" }}, + }; + static gint *ett[] = { + &ett_chdlc, + }; + + 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_add("chdlctype", CISCO_SLARP, dissect_slarp, proto_slarp); +} |