323 lines
8.7 KiB
C
323 lines
8.7 KiB
C
/* packet-sscop.c
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* Routines for SSCOP (Q.2110, Q.SAAL) frame disassembly
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* Guy Harris <guy@alum.mit.edu>
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*
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* $Id: packet-sscop.c,v 1.6 2000/03/12 04:47:50 gram Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@zing.org>
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* Copyright 1998
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*
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#ifdef HAVE_SYS_TYPES_H
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# include <sys/types.h>
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#endif
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#include <stdio.h>
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#include <glib.h>
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#include <string.h>
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#include "packet.h"
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#include "packet-q2931.h"
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static int proto_sscop = -1;
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static gint ett_sscop = -1;
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/*
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* See
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*
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* http://www.protocols.com/pbook/atmsig.htm
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*
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* for some information on SSCOP, although, alas, not the actual PDU
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* type values - those I got from the FreeBSD 3.2 ATM code.
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*/
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/*
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* SSCOP PDU types.
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*/
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#define SSCOP_TYPE_MASK 0x0f
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#define SSCOP_BGN 0x01 /* Begin */
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#define SSCOP_BGAK 0x02 /* Begin Acknowledge */
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#define SSCOP_BGREJ 0x07 /* Begin Reject */
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#define SSCOP_END 0x03 /* End */
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#define SSCOP_ENDAK 0x04 /* End Acknowledge */
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#define SSCOP_RS 0x05 /* Resynchronization */
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#define SSCOP_RSAK 0x06 /* Resynchronization Acknowledge */
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#define SSCOP_SD 0x08 /* Sequenced Data */
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#define SSCOP_SDP 0x09 /* Sequenced Data with Poll */
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#define SSCOP_POLL 0x0a /* Status Request */
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#define SSCOP_STAT 0x0b /* Solicited Status Response */
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#define SSCOP_USTAT 0x0c /* Unsolicited Status Response */
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#define SSCOP_UD 0x0d /* Unnumbered Data */
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#define SSCOP_MD 0x0e /* Management Data */
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#define SSCOP_ER 0x09 /* Error Recovery */
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#define SSCOP_ERAK 0x0f /* Error Acknowledge */
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#define SSCOP_S 0x10 /* Source bit in End PDU */
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/*
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* XXX - how to distinguish SDP from ER?
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*/
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static const value_string sscop_type_vals[] = {
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{ SSCOP_BGN, "Begin" },
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{ SSCOP_BGAK, "Begin Acknowledge" },
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{ SSCOP_BGREJ, "Begin Reject" },
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{ SSCOP_END, "End" },
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{ SSCOP_ENDAK, "End Acknowledge" },
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{ SSCOP_RS, "Resynchronization" },
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{ SSCOP_RSAK, "Resynchronization Acknowledge" },
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{ SSCOP_SD, "Sequenced Data" },
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#if 0
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{ SSCOP_SDP, "Sequenced Data with Poll" },
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#endif
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{ SSCOP_POLL, "Status Request" },
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{ SSCOP_STAT, "Solicited Status Response" },
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{ SSCOP_USTAT, "Unsolicited Status Response" },
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{ SSCOP_UD, "Unnumbered Data" },
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{ SSCOP_MD, "Management Data" },
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{ SSCOP_ER, "Error Recovery" },
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{ SSCOP_ERAK, "Error Acknowledge" },
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{ 0, NULL }
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};
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/*
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* The SSCOP "header" is a trailer, so the "offsets" are computed based
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* on the length of the packet.
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*/
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/*
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* PDU type.
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*/
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#define SSCOP_PDU_TYPE (pi.len - 4) /* single byte */
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/*
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* Begin PDU, Begin Acknowledge PDU (no N(SQ) in it), Resynchronization
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* PDU, Resynchronization Acknowledge PDU (no N(SQ) in it in Q.SAAL),
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* Error Recovery PDU, Error Recovery Acknoledge PDU (no N(SQ) in it).
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*/
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#define SSCOP_N_SQ (pi.len - 5) /* One byte */
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#define SSCOP_N_MR (pi.len - 4) /* lower 3 bytes thereof */
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/*
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* Sequenced Data PDU (no N(PS) in it), Sequenced Data with Poll PDU,
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* Poll PDU.
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*/
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#define SSCOP_N_PS (pi.len - 8) /* lower 3 bytes thereof */
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#define SSCOP_N_S (pi.len - 4) /* lower 3 bytes thereof */
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/*
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* Solicited Status PDU, Unsolicited Status PDU (no N(PS) in it).
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*/
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#define SSCOP_SS_N_PS (pi.len - 12) /* lower 3 bytes thereof */
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#define SSCOP_SS_N_MR (pi.len - 8) /* lower 3 bytes thereof */
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#define SSCOP_SS_N_R (pi.len - 4) /* lower 3 bytes thereof */
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void
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dissect_sscop(const u_char *pd, int offset, frame_data *fd, proto_tree *tree)
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{
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proto_item *ti;
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proto_tree *sscop_tree = NULL;
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guint8 pdu_type;
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int pdu_len;
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int pad_len;
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/*
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* The SSCOP "header" is a trailer, and the PDU type is in the
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* last-minus-3 byte of the frame; if the captured length is less
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* than the actual length by 3 or more bytes, give up, as we don't
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* have the PDU type.
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*/
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if ((pi.len - pi.captured_len) >= 3) {
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dissect_data(pd, offset, fd, tree);
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return;
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}
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pdu_type = pd[SSCOP_PDU_TYPE] & SSCOP_TYPE_MASK;
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if (check_col(fd, COL_PROTOCOL))
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col_add_str(fd, COL_PROTOCOL, "SSCOP");
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if (check_col(fd, COL_INFO))
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col_add_str(fd, COL_INFO, val_to_str(pdu_type, sscop_type_vals,
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"Unknown PDU type (0x%02x)"));
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/*
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* Find the length of the PDU and, if there's any payload and
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* padding, the length of the padding.
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*/
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switch (pdu_type) {
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case SSCOP_SD:
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pad_len = (pd[SSCOP_PDU_TYPE] >> 6) & 0x03;
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pdu_len = 4;
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break;
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case SSCOP_BGN:
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case SSCOP_BGAK:
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case SSCOP_BGREJ:
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case SSCOP_END:
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case SSCOP_RS:
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#if 0
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case SSCOP_SDP:
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#endif
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pad_len = (pd[SSCOP_PDU_TYPE] >> 6) & 0x03;
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pdu_len = 8;
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break;
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case SSCOP_UD:
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pad_len = (pd[SSCOP_PDU_TYPE] >> 6) & 0x03;
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pdu_len = 4;
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break;
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default:
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pad_len = 0;
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pdu_len = pi.len; /* No payload, just SSCOP */
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break;
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}
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_sscop, pi.len - pdu_len,
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pdu_len, "SSCOP");
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sscop_tree = proto_item_add_subtree(ti, ett_sscop);
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proto_tree_add_text(sscop_tree, SSCOP_PDU_TYPE, 1,
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"PDU Type: %s",
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val_to_str(pdu_type, sscop_type_vals,
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"Unknown (0x%02x)"));
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switch (pdu_type) {
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case SSCOP_BGN:
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case SSCOP_RS:
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case SSCOP_ER:
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proto_tree_add_text(sscop_tree, SSCOP_N_SQ, 1,
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"N(SQ): %u", pd[SSCOP_N_SQ]);
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proto_tree_add_text(sscop_tree, SSCOP_N_MR + 1, 3,
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"N(MR): %u", pntohl(&pd[SSCOP_N_MR]) & 0xFFFFFF);
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break;
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case SSCOP_END:
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proto_tree_add_text(sscop_tree, SSCOP_PDU_TYPE, 1,
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"Source: %s", (pd[SSCOP_PDU_TYPE] & SSCOP_S) ? "SSCOP" : "User");
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break;
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case SSCOP_BGAK:
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case SSCOP_RSAK:
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proto_tree_add_text(sscop_tree, SSCOP_N_MR + 1, 3,
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"N(MR): %u", pntohl(&pd[SSCOP_N_MR]) & 0xFFFFFF);
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break;
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case SSCOP_ERAK:
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proto_tree_add_text(sscop_tree, SSCOP_N_MR + 3, 3,
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"N(MR): %u", pntohl(&pd[SSCOP_N_MR]) & 0xFFFFFF);
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break;
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case SSCOP_SD:
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proto_tree_add_text(sscop_tree, SSCOP_N_S + 1, 3,
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"N(S): %u", pntohl(&pd[SSCOP_N_S]) & 0xFFFFFF);
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break;
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#if 0
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case SSCOP_SDP:
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#endif
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case SSCOP_POLL:
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proto_tree_add_text(sscop_tree, SSCOP_N_PS + 1, 3,
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"N(PS): %u", pntohl(&pd[SSCOP_N_PS]) & 0xFFFFFF);
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proto_tree_add_text(sscop_tree, SSCOP_N_S + 1, 3,
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"N(S): %u", pntohl(&pd[SSCOP_N_S]) & 0xFFFFFF);
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break;
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case SSCOP_STAT:
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/*
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* XXX - dissect the list elements....
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*/
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proto_tree_add_text(sscop_tree, SSCOP_SS_N_PS + 1, 3,
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"N(PS): %u", pntohl(&pd[SSCOP_SS_N_PS]) & 0xFFFFFF);
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proto_tree_add_text(sscop_tree, SSCOP_SS_N_MR + 1, 3,
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"N(MR): %u", pntohl(&pd[SSCOP_SS_N_MR]) & 0xFFFFFF);
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proto_tree_add_text(sscop_tree, SSCOP_SS_N_R + 1, 3,
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"N(R): %u", pntohl(&pd[SSCOP_SS_N_R]) & 0xFFFFFF);
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break;
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case SSCOP_USTAT:
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/*
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* XXX - dissect the list elements....
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*/
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proto_tree_add_text(sscop_tree, SSCOP_SS_N_MR + 1, 3,
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"N(MR): %u", pntohl(&pd[SSCOP_SS_N_MR]) & 0xFFFFFF);
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proto_tree_add_text(sscop_tree, SSCOP_SS_N_R + 1, 3,
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"N(R): %u", pntohl(&pd[SSCOP_SS_N_R]) & 0xFFFFFF);
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break;
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}
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}
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/*
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* Dissect the payload, if any.
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*
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* XXX - what about a Management Data PDU?
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*/
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switch (pdu_type) {
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case SSCOP_SD:
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case SSCOP_UD:
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case SSCOP_BGN:
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case SSCOP_BGAK:
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case SSCOP_BGREJ:
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case SSCOP_END:
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case SSCOP_RS:
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#if 0
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case SSCOP_SDP:
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#endif
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if (tree) {
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proto_tree_add_text(sscop_tree, SSCOP_PDU_TYPE, 1,
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"Pad length: %u", pad_len);
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}
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/*
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* Compute length of data in PDU - subtract the trailer length
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* and the pad length.
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*/
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pi.len -= (pdu_len + pad_len);
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if (pi.len < pi.captured_len)
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pi.captured_len = pi.len;
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/*
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* XXX - if more than just Q.2931 uses SSCOP, we need to tell
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* SSCOP what dissector to use here.
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*/
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if (pi.len != 0) {
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if (pdu_type == SSCOP_SD)
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dissect_q2931(pd, offset, fd, tree);
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else
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dissect_data(pd, offset, fd, tree);
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}
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break;
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}
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}
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void
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proto_register_sscop(void)
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{
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static gint *ett[] = {
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&ett_sscop,
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};
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proto_sscop = proto_register_protocol("SSCOP", "sscop");
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proto_register_subtree_array(ett, array_length(ett));
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}
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