Add support for SSCOP protocol; dissect signalling AAL packets using it.

It's in a file of its own, as I think there may be, or may have been
proposed, non-ATM uses of it as well.

svn path=/trunk/; revision=1064

1 files changed, 286 insertions, 0 deletions

diff --git a/packet-sscop.c b/packet-sscop.c
new file mode 100644
index 0000000000..34a40a3ec4
--- /dev/null
+++ b/packet-sscop.c
@@ -0,0 +1,286 @@
+/* packet-sscop.c
+ * Routines for SSCOP (Q.2110, Q.SAAL) frame disassembly
+ * Guy Harris <guy@alum.mit.edu>
+ *
+ * $Id: packet-sscop.c,v 1.1 1999/11/19 07:28:15 guy Exp $
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@zing.org>
+ * 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
+
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+
+#include <stdio.h>
+#include <glib.h>
+#include <string.h>
+#include "packet.h"
+
+static int proto_sscop = -1;
+
+static gint ett_sscop = -1;
+
+/*
+ * 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 */
+
+/*
+ * 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	(pi.len - 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	(pi.len - 8)	/* lower 3 bytes thereof */
+#define	SSCOP_N_MR	(pi.len - 4)	/* lower 3 bytes thereof */
+
+/*
+ * Sequenced Data PDU (no N(PS) in it), Sequenced Data with Poll PDU,
+ * Poll PDU.
+ */
+#define	SSCOP_N_PS	(pi.len - 8)	/* lower 3 bytes thereof */
+#define	SSCOP_N_S	(pi.len - 4)	/* lower 3 bytes thereof */
+
+/*
+ * Solicited Status PDU, Unsolicited Status PDU (no N(PS) in it).
+ */
+#define	SSCOP_SS_N_PS	(pi.len - 12)	/* lower 3 bytes thereof */
+#define	SSCOP_SS_N_MR	(pi.len - 8)	/* lower 3 bytes thereof */
+#define	SSCOP_SS_N_R	(pi.len - 4)	/* lower 3 bytes thereof */
+
+void
+dissect_sscop(const u_char *pd, int offset, frame_data *fd, proto_tree *tree) 
+{
+  proto_item *ti;
+  proto_tree *sscop_tree;
+  guint8 pdu_type;
+  int pdu_len;
+  int pad_len;
+
+  /*
+   * The SSCOP "header" is a trailer, and the PDU type is in the
+   * last-minus-3 byte of the frame; if the captured length is less
+   * than the actual length by 3 or more bytes, give up, as we don't
+   * have the PDU type.
+   */
+  if ((pi.len - pi.captured_len) >= 3) {
+    dissect_data(pd, offset, fd, tree);
+    return;
+  }
+  pdu_type = pd[SSCOP_PDU_TYPE] & SSCOP_TYPE_MASK;
+  if (check_col(fd, COL_PROTOCOL))
+    col_add_str(fd, COL_PROTOCOL, "SSCOP");
+  if (check_col(fd, COL_INFO))
+    col_add_str(fd, COL_INFO, val_to_str(pdu_type, sscop_type_vals,
+					"Unknown PDU type (0x%02x)"));
+
+  if (tree) {
+    /*
+     * 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 = (pd[SSCOP_PDU_TYPE] >> 6) & 0x03;
+      pdu_len = 4;
+      break;
+
+#if 0
+    case SSCOP_SDP:
+      pad_len = (pd[SSCOP_PDU_TYPE] >> 6) & 0x03;
+      pdu_len = 8;
+      break;
+#endif
+
+    case SSCOP_UD:
+      pad_len = (pd[SSCOP_PDU_TYPE] >> 6) & 0x03;
+      pdu_len = 4;
+      break;
+
+    default:
+      pad_len = 0;
+      pdu_len = pi.len;	/* No payload, just SSCOP */
+      break;
+    }
+    ti = proto_tree_add_item_format(tree, proto_sscop, pi.len - pdu_len,
+    					pdu_len, NULL, "SSCOP");
+    sscop_tree = proto_item_add_subtree(ti, ett_sscop);
+    switch (pdu_type) {
+
+    case SSCOP_BGN:
+    case SSCOP_BGAK:
+    case SSCOP_RS:
+    case SSCOP_ER:
+      proto_tree_add_text(sscop_tree, SSCOP_N_SQ + 1, 3,
+          "N(SQ): %u", pntohl(&pd[SSCOP_N_SQ]) & 0xFFFFFF);
+      proto_tree_add_text(sscop_tree, SSCOP_N_MR + 1, 3,
+          "N(MR): %u", pntohl(&pd[SSCOP_N_MR]) & 0xFFFFFF);
+      break;
+
+    case SSCOP_RSAK:
+      proto_tree_add_text(sscop_tree, SSCOP_N_MR + 1, 3,
+          "N(MR): %u", pntohl(&pd[SSCOP_N_MR]) & 0xFFFFFF);
+      break;
+
+    case SSCOP_ERAK:
+      proto_tree_add_text(sscop_tree, SSCOP_N_MR + 3, 3,
+          "N(MR): %u", pntohl(&pd[SSCOP_N_MR]) & 0xFFFFFF);
+      break;
+
+    case SSCOP_SD:
+      proto_tree_add_text(sscop_tree, SSCOP_N_S + 1, 3,
+          "N(S): %u", pntohl(&pd[SSCOP_N_S]) & 0xFFFFFF);
+      break;
+
+#if 0
+    case SSCOP_SDP:
+#endif
+    case SSCOP_POLL:
+      proto_tree_add_text(sscop_tree, SSCOP_N_PS + 1, 3,
+          "N(PS): %u", pntohl(&pd[SSCOP_N_PS]) & 0xFFFFFF);
+      proto_tree_add_text(sscop_tree, SSCOP_N_S + 1, 3,
+          "N(S): %u", pntohl(&pd[SSCOP_N_S]) & 0xFFFFFF);
+      break;
+
+    case SSCOP_STAT:
+      /*
+       * XXX - dissect the list elements....
+       */
+      proto_tree_add_text(sscop_tree, SSCOP_SS_N_PS + 1, 3,
+          "N(PS): %u", pntohl(&pd[SSCOP_SS_N_PS]) & 0xFFFFFF);
+      proto_tree_add_text(sscop_tree, SSCOP_SS_N_MR + 1, 3,
+          "N(MR): %u", pntohl(&pd[SSCOP_SS_N_MR]) & 0xFFFFFF);
+      proto_tree_add_text(sscop_tree, SSCOP_SS_N_R + 1, 3,
+          "N(R): %u", pntohl(&pd[SSCOP_SS_N_R]) & 0xFFFFFF);
+      break;
+
+    case SSCOP_USTAT:
+      /*
+       * XXX - dissect the list elements....
+       */
+      proto_tree_add_text(sscop_tree, SSCOP_SS_N_MR + 1, 3,
+          "N(MR): %u", pntohl(&pd[SSCOP_SS_N_MR]) & 0xFFFFFF);
+      proto_tree_add_text(sscop_tree, SSCOP_SS_N_R + 1, 3,
+          "N(R): %u", pntohl(&pd[SSCOP_SS_N_R]) & 0xFFFFFF);
+      break;
+    }
+
+    proto_tree_add_text(sscop_tree, SSCOP_PDU_TYPE, 1,
+			"PDU Type: %s",
+			val_to_str(pdu_type, sscop_type_vals,
+				"Unknown (0x%02x)"));
+    /*
+     * XXX - what about a Management Data PDU?
+     */
+    switch (pdu_type) {
+
+    case SSCOP_SD:
+    case SSCOP_UD:
+      pad_len = (pd[SSCOP_PDU_TYPE] >> 6) & 0x03;
+      proto_tree_add_text(sscop_tree, SSCOP_PDU_TYPE, 1,
+			"Pad length: %u", pad_len);
+
+      /*
+       * Compute length of data in PDU - subtract the trailer length
+       * and the pad length.
+       */
+      pi.len -= (pdu_len + pad_len);
+      if (pi.len < pi.captured_len)
+        pi.captured_len = pi.len;
+      dissect_data(pd, offset, fd, tree);
+      break;
+    }
+  }
+}
+
+void
+proto_register_sscop(void)
+{
+	static gint *ett[] = {
+		&ett_sscop,
+	};
+	proto_sscop = proto_register_protocol("SSCOP", "sscop");
+	proto_register_subtree_array(ett, array_length(ett));
+}