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Diffstat (limited to 'epan/dissectors/packet-isdn.c')
| -rw-r--r-- | epan/dissectors/packet-isdn.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/epan/dissectors/packet-isdn.c b/epan/dissectors/packet-isdn.c new file mode 100644 index 0000000000..e1c2337cc2 --- /dev/null +++ b/epan/dissectors/packet-isdn.c @@ -0,0 +1,216 @@ +/* packet-isdn.c + * Routines for ISDN packet disassembly + * + * $Id$ + * + * Ethereal - Network traffic analyzer + * By Gerald Combs <gerald@ethereal.com> + * 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 <stdio.h> +#include <glib.h> +#include <epan/packet.h> +#include <epan/circuit.h> + +static int proto_isdn = -1; +static int hf_isdn_channel = -1; + +static gint ett_isdn = -1; + +static dissector_handle_t lapd_handle; +static dissector_handle_t ppp_hdlc_handle; +static dissector_handle_t v120_handle; +static dissector_handle_t data_handle; + +static const value_string channel_vals[] = { + { 0, "D" }, + { 1, "B1" }, + { 2, "B2" }, + { 3, "B3" }, + { 4, "B4" }, + { 5, "B5" }, + { 6, "B6" }, + { 7, "B7" }, + { 8, "B8" }, + { 9, "B9" }, + { 10, "B10" }, + { 11, "B11" }, + { 12, "B12" }, + { 13, "B13" }, + { 14, "B14" }, + { 15, "B15" }, + { 16, "B16" }, + { 17, "B17" }, + { 18, "B19" }, + { 19, "B19" }, + { 20, "B20" }, + { 21, "B21" }, + { 22, "B22" }, + { 23, "B23" }, + { 24, "B24" }, + { 25, "B25" }, + { 26, "B26" }, + { 27, "B27" }, + { 28, "B29" }, + { 29, "B29" }, + { 30, "B30" }, + { 0, NULL } +}; + +static void +dissect_isdn(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) +{ + proto_tree *isdn_tree; + proto_item *ti; + static const guint8 v120_sabme[3] = { 0x08, 0x01, 0x7F }; + static const guint8 ppp[2] = { 0xFF, 0x03 }; + circuit_t *circuit; + + if (check_col(pinfo->cinfo, COL_PROTOCOL)) + col_set_str(pinfo->cinfo, COL_PROTOCOL, "ISDN"); + + if (pinfo->pseudo_header->isdn.uton) { + if (check_col(pinfo->cinfo, COL_RES_DL_DST)) + col_set_str(pinfo->cinfo, COL_RES_DL_DST, "Network"); + if (check_col(pinfo->cinfo, COL_RES_DL_SRC)) + col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "User"); + } else { + if (check_col(pinfo->cinfo, COL_RES_DL_DST)) + col_set_str(pinfo->cinfo, COL_RES_DL_DST, "User"); + if (check_col(pinfo->cinfo, COL_RES_DL_SRC)) + col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "Network"); + } + + pinfo->ctype = CT_ISDN; + pinfo->circuit_id = pinfo->pseudo_header->isdn.channel; + + if (tree) { + ti = proto_tree_add_item(tree, proto_isdn, tvb, 0, 0, FALSE); + isdn_tree = proto_item_add_subtree(ti, ett_isdn); + + proto_tree_add_uint(isdn_tree, hf_isdn_channel, tvb, 0, 0, + pinfo->pseudo_header->isdn.channel); + } + + /* + * Set up a circuit for this channel, and assign it a dissector. + */ + circuit = find_circuit(pinfo->ctype, pinfo->circuit_id, pinfo->fd->num); + if (circuit == NULL) + circuit = circuit_new(pinfo->ctype, pinfo->circuit_id, + pinfo->fd->num); + + if (circuit_get_dissector(circuit) == NULL) { + /* + * We don't yet know the type of traffic on the circuit. + */ + switch (pinfo->pseudo_header->isdn.channel) { + + case 0: + /* + * D-channel. Treat it as LAPD. + */ + circuit_set_dissector(circuit, lapd_handle); + break; + + default: + /* + * B-channel. + * + * We don't know yet whether the datastream is + * V.120 or not; this heuristic tries to figure + * that out. + * + * We cannot glean this from the Q.931 SETUP message, + * because no commercial V.120 implementation I've + * seen actually sets the V.120 protocol discriminator + * (that, or I'm misreading the spec badly). + * + * TODO: close the circuit after a close on the B + * channel is detected. + * + * -Bert Driehuis (from the i4btrace reader; + * this heuristic was moved from there to + * here) + * + * XXX - I don't know that one can guarantee that + * the SABME will appear in the first frame on + * the channels, so we probably can't just say + * "it must be PPP" if we don't immediately see + * the V.120 SABME frame, so we do so only if + * we see the 0xFF 0x03. Unfortunately, that + * won't do the right thing if the PPP-over-HDLC + * headers aren't being used.... + */ + if (tvb_memeql(tvb, 0, v120_sabme, 3) == 0) { + /* + * We assume this is V.120. + */ + circuit_set_dissector(circuit, v120_handle); + } else if (tvb_memeql(tvb, 0, ppp, 2) == 0) { + /* + * We assume this is PPP. + */ + circuit_set_dissector(circuit, ppp_hdlc_handle); + } + break; + } + } + + if (!try_circuit_dissector(pinfo->ctype, pinfo->circuit_id, + pinfo->fd->num, tvb, pinfo, tree)) + call_dissector(data_handle, tvb, pinfo, tree); +} + +void +proto_register_isdn(void) +{ + static hf_register_info hf[] = { + { &hf_isdn_channel, + { "Channel", "isdn.channel", FT_UINT8, BASE_DEC, + VALS(channel_vals), 0x0, "", HFILL }}, + }; + static gint *ett[] = { + &ett_isdn, + }; + proto_isdn = proto_register_protocol("ISDN", "ISDN", "isdn"); + proto_register_field_array(proto_isdn, hf, array_length(hf)); + proto_register_subtree_array(ett, array_length(ett)); +} + +void +proto_reg_handoff_isdn(void) +{ + dissector_handle_t isdn_handle; + + /* + * Get handles for the LAPD, PPP, and V.120 dissectors. + */ + lapd_handle = find_dissector("lapd"); + ppp_hdlc_handle = find_dissector("ppp_hdlc"); + v120_handle = find_dissector("v120"); + data_handle = find_dissector("data"); + + isdn_handle = create_dissector_handle(dissect_isdn, proto_isdn); + + dissector_add("wtap_encap", WTAP_ENCAP_ISDN, isdn_handle); +} |