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diff --git a/epan/dissectors/packet-sscop.c b/epan/dissectors/packet-sscop.c
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+/* packet-sscop.c
+ * Routines for SSCOP (Q.2110, Q.SAAL) frame disassembly
+ * Guy Harris <guy@alum.mit.edu>
+ *
+ * $Id$
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * Copyright 1998
+ *
+ *
+ * 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 <string.h>
+#include <epan/packet.h>
+
+static int proto_sscop = -1;
+
+static gint ett_sscop = -1;
+
+static dissector_handle_t q2931_handle;
+static dissector_handle_t data_handle;
+
+/*
+ * See
+ *
+ * http://www.protocols.com/pbook/atmsig.htm
+ *
+ * for some information on SSCOP, although, alas, not the actual PDU
+ * type values - those I got from the FreeBSD 3.2 ATM code.
+ */
+
+/*
+ * SSCOP PDU types.
+ */
+#define SSCOP_TYPE_MASK 0x0f
+
+#define SSCOP_BGN 0x01 /* Begin */
+#define SSCOP_BGAK 0x02 /* Begin Acknowledge */
+#define SSCOP_BGREJ 0x07 /* Begin Reject */
+#define SSCOP_END 0x03 /* End */
+#define SSCOP_ENDAK 0x04 /* End Acknowledge */
+#define SSCOP_RS 0x05 /* Resynchronization */
+#define SSCOP_RSAK 0x06 /* Resynchronization Acknowledge */
+#define SSCOP_SD 0x08 /* Sequenced Data */
+#define SSCOP_SDP 0x09 /* Sequenced Data with Poll */
+#define SSCOP_POLL 0x0a /* Status Request */
+#define SSCOP_STAT 0x0b /* Solicited Status Response */
+#define SSCOP_USTAT 0x0c /* Unsolicited Status Response */
+#define SSCOP_UD 0x0d /* Unnumbered Data */
+#define SSCOP_MD 0x0e /* Management Data */
+#define SSCOP_ER 0x09 /* Error Recovery */
+#define SSCOP_ERAK 0x0f /* Error Acknowledge */
+
+#define SSCOP_S 0x10 /* Source bit in End PDU */
+
+/*
+ * XXX - how to distinguish SDP from ER?
+ */
+static const value_string sscop_type_vals[] = {
+ { SSCOP_BGN, "Begin" },
+ { SSCOP_BGAK, "Begin Acknowledge" },
+ { SSCOP_BGREJ, "Begin Reject" },
+ { SSCOP_END, "End" },
+ { SSCOP_ENDAK, "End Acknowledge" },
+ { SSCOP_RS, "Resynchronization" },
+ { SSCOP_RSAK, "Resynchronization Acknowledge" },
+ { SSCOP_SD, "Sequenced Data" },
+#if 0
+ { SSCOP_SDP, "Sequenced Data with Poll" },
+#endif
+ { SSCOP_POLL, "Status Request" },
+ { SSCOP_STAT, "Solicited Status Response" },
+ { SSCOP_USTAT, "Unsolicited Status Response" },
+ { SSCOP_UD, "Unnumbered Data" },
+ { SSCOP_MD, "Management Data" },
+ { SSCOP_ER, "Error Recovery" },
+ { SSCOP_ERAK, "Error Acknowledge" },
+ { 0, NULL }
+};
+
+/*
+ * The SSCOP "header" is a trailer, so the "offsets" are computed based
+ * on the length of the packet.
+ */
+
+/*
+ * PDU type.
+ */
+#define SSCOP_PDU_TYPE (reported_length - 4) /* single byte */
+
+/*
+ * Begin PDU, Begin Acknowledge PDU (no N(SQ) in it), Resynchronization
+ * PDU, Resynchronization Acknowledge PDU (no N(SQ) in it in Q.SAAL),
+ * Error Recovery PDU, Error Recovery Acknoledge PDU (no N(SQ) in it).
+ */
+#define SSCOP_N_SQ (reported_length - 5) /* One byte */
+#define SSCOP_N_MR (reported_length - 4) /* lower 3 bytes thereof */
+
+/*
+ * Sequenced Data PDU (no N(PS) in it), Sequenced Data with Poll PDU,
+ * Poll PDU.
+ */
+#define SSCOP_N_PS (reported_length - 8) /* lower 3 bytes thereof */
+#define SSCOP_N_S (reported_length - 4) /* lower 3 bytes thereof */
+
+/*
+ * Solicited Status PDU, Unsolicited Status PDU (no N(PS) in it).
+ */
+#define SSCOP_SS_N_PS (reported_length - 12) /* lower 3 bytes thereof */
+#define SSCOP_SS_N_MR (reported_length - 8) /* lower 3 bytes thereof */
+#define SSCOP_SS_N_R (reported_length - 4) /* lower 3 bytes thereof */
+
+static void
+dissect_sscop(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+ guint reported_length;
+ proto_item *ti;
+ proto_tree *sscop_tree = NULL;
+ guint8 sscop_pdu_type;
+ guint8 pdu_type;
+ int pdu_len;
+ int pad_len;
+ tvbuff_t *next_tvb;
+
+ reported_length = tvb_reported_length(tvb); /* frame length */
+ sscop_pdu_type = tvb_get_guint8(tvb, SSCOP_PDU_TYPE);
+ pdu_type = sscop_pdu_type & SSCOP_TYPE_MASK;
+ if (check_col(pinfo->cinfo, COL_PROTOCOL))
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "SSCOP");
+ if (check_col(pinfo->cinfo, COL_INFO))
+ col_add_str(pinfo->cinfo, COL_INFO, val_to_str(pdu_type, sscop_type_vals,
+ "Unknown PDU type (0x%02x)"));
+
+ /*
+ * Find the length of the PDU and, if there's any payload and
+ * padding, the length of the padding.
+ */
+ switch (pdu_type) {
+
+ case SSCOP_SD:
+ pad_len = (sscop_pdu_type >> 6) & 0x03;
+ pdu_len = 4;
+ break;
+
+ case SSCOP_BGN:
+ case SSCOP_BGAK:
+ case SSCOP_BGREJ:
+ case SSCOP_END:
+ case SSCOP_RS:
+#if 0
+ case SSCOP_SDP:
+#endif
+ pad_len = (sscop_pdu_type >> 6) & 0x03;
+ pdu_len = 8;
+ break;
+
+ case SSCOP_UD:
+ pad_len = (sscop_pdu_type >> 6) & 0x03;
+ pdu_len = 4;
+ break;
+
+ default:
+ pad_len = 0;
+ pdu_len = reported_length; /* No payload, just SSCOP */
+ break;
+ }
+ if (tree) {
+ ti = proto_tree_add_protocol_format(tree, proto_sscop, tvb,
+ reported_length - pdu_len,
+ pdu_len, "SSCOP");
+ sscop_tree = proto_item_add_subtree(ti, ett_sscop);
+
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_PDU_TYPE, 1,
+ "PDU Type: %s",
+ val_to_str(pdu_type, sscop_type_vals,
+ "Unknown (0x%02x)"));
+
+ switch (pdu_type) {
+
+ case SSCOP_BGN:
+ case SSCOP_RS:
+ case SSCOP_ER:
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_N_SQ, 1,
+ "N(SQ): %u", tvb_get_guint8(tvb, SSCOP_N_SQ));
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_N_MR + 1, 3,
+ "N(MR): %u", tvb_get_ntohl(tvb, SSCOP_N_MR) & 0xFFFFFF);
+ break;
+
+ case SSCOP_END:
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_PDU_TYPE, 1,
+ "Source: %s", (sscop_pdu_type & SSCOP_S) ? "SSCOP" : "User");
+ break;
+
+ case SSCOP_BGAK:
+ case SSCOP_RSAK:
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_N_MR + 1, 3,
+ "N(MR): %u", tvb_get_ntohl(tvb, SSCOP_N_MR) & 0xFFFFFF);
+ break;
+
+ case SSCOP_ERAK:
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_N_MR + 3, 3,
+ "N(MR): %u", tvb_get_ntohl(tvb, SSCOP_N_MR) & 0xFFFFFF);
+ break;
+
+ case SSCOP_SD:
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_N_S + 1, 3,
+ "N(S): %u", tvb_get_ntohl(tvb, SSCOP_N_S) & 0xFFFFFF);
+ break;
+
+#if 0
+ case SSCOP_SDP:
+#endif
+ case SSCOP_POLL:
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_N_PS + 1, 3,
+ "N(PS): %u", tvb_get_ntohl(tvb, SSCOP_N_PS) & 0xFFFFFF);
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_N_S + 1, 3,
+ "N(S): %u", tvb_get_ntohl(tvb, SSCOP_N_S) & 0xFFFFFF);
+ break;
+
+ case SSCOP_STAT:
+ /*
+ * XXX - dissect the list elements....
+ */
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_SS_N_PS + 1, 3,
+ "N(PS): %u", tvb_get_ntohl(tvb, SSCOP_SS_N_PS) & 0xFFFFFF);
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_SS_N_MR + 1, 3,
+ "N(MR): %u", tvb_get_ntohl(tvb, SSCOP_SS_N_MR) & 0xFFFFFF);
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_SS_N_R + 1, 3,
+ "N(R): %u", tvb_get_ntohl(tvb, SSCOP_SS_N_R) & 0xFFFFFF);
+ break;
+
+ case SSCOP_USTAT:
+ /*
+ * XXX - dissect the list elements....
+ */
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_SS_N_MR + 1, 3,
+ "N(MR): %u", tvb_get_ntohl(tvb, SSCOP_SS_N_MR) & 0xFFFFFF);
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_SS_N_R + 1, 3,
+ "N(R): %u", tvb_get_ntohl(tvb, SSCOP_SS_N_R) & 0xFFFFFF);
+ break;
+ }
+ }
+
+ /*
+ * Dissect the payload, if any.
+ *
+ * XXX - what about a Management Data PDU?
+ */
+ switch (pdu_type) {
+
+ case SSCOP_SD:
+ case SSCOP_UD:
+ case SSCOP_BGN:
+ case SSCOP_BGAK:
+ case SSCOP_BGREJ:
+ case SSCOP_END:
+ case SSCOP_RS:
+#if 0
+ case SSCOP_SDP:
+#endif
+ if (tree) {
+ proto_tree_add_text(sscop_tree, tvb, SSCOP_PDU_TYPE, 1,
+ "Pad length: %u", pad_len);
+ }
+
+ /*
+ * Compute length of data in PDU - subtract the trailer length
+ * and the pad length from the reported length.
+ */
+ reported_length -= (pdu_len + pad_len);
+
+ /*
+ * XXX - if more than just Q.2931 uses SSCOP, we need to tell
+ * SSCOP what dissector to use here.
+ */
+ if (reported_length != 0) {
+ /*
+ * We know that we have all of the payload, because we know we have
+ * at least 4 bytes of data after the payload, i.e. the SSCOP trailer.
+ * Therefore, we know that the captured length of the payload is
+ * equal to the length of the payload.
+ */
+ next_tvb = tvb_new_subset(tvb, 0, reported_length, reported_length);
+ if (pdu_type == SSCOP_SD)
+ call_dissector(q2931_handle, next_tvb, pinfo, tree);
+ else
+ call_dissector(data_handle,next_tvb, pinfo, tree);
+ }
+ break;
+ }
+}
+
+void
+proto_register_sscop(void)
+{
+ static gint *ett[] = {
+ &ett_sscop,
+ };
+ proto_sscop = proto_register_protocol("SSCOP", "SSCOP", "sscop");
+ proto_register_subtree_array(ett, array_length(ett));
+ register_dissector("sscop", dissect_sscop, proto_sscop);
+}
+
+void
+proto_reg_handoff_sscop(void)
+{
+ /*
+ * Get handle for the Q.2931 dissector.
+ */
+ q2931_handle = find_dissector("q2931");
+ data_handle = find_dissector("data");
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-19 10:59:38 +0000