OptoMMP Dissector

Change-Id: I754335b9944a9de169e37c16a3e37a86d35543a6
Reviewed-on: https://code.wireshark.org/review/3110
Petri-Dish: Evan Huus <eapache@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Evan Huus <eapache@gmail.com>

3 files changed, 891 insertions, 0 deletions

diff --git a/epan/CMakeLists.txt b/epan/CMakeLists.txt
index 048b8a7661..3998a7a497 100644
--- a/epan/CMakeLists.txt
+++ b/epan/CMakeLists.txt
@@ -1052,6 +1052,7 @@ set(DISSECTOR_SRC
 	dissectors/packet-openvpn.c
 	dissectors/packet-openwire.c
 	dissectors/packet-opsi.c
+    dissectors/packet-optommp.c
 	dissectors/packet-osc.c
 	dissectors/packet-osi-options.c
 	dissectors/packet-osi.c
diff --git a/epan/dissectors/Makefile.common b/epan/dissectors/Makefile.common
index f9b8965e5e..243c06d548 100644
--- a/epan/dissectors/Makefile.common
+++ b/epan/dissectors/Makefile.common
@@ -976,6 +976,7 @@ DISSECTOR_SRC = \
 	packet-opensafety.c	\
 	packet-openvpn.c	\
 	packet-openwire.c	\
+    packet-optommp.c \
 	packet-osc.c	\
 	packet-osi-options.c	\
 	packet-osi.c		\
diff --git a/epan/dissectors/packet-optommp.c b/epan/dissectors/packet-optommp.c
new file mode 100644
index 0000000000..9f5ece6b25
--- /dev/null
+++ b/epan/dissectors/packet-optommp.c
@@ -0,0 +1,889 @@
+/* packet-optommp.c
+ * Routines for optommp dissection
+ * Copyright 2014, Opto22 wiresharkdissectorcoder@gmail.com
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/* Tabsize: 4 */
+
+#include "config.h"
+
+#include <glib.h>
+
+#include <epan/packet.h>
+#include <epan/dissectors/packet-tcp.h>
+#include <epan/proto.h>
+#include <epan/wmem/wmem.h>
+#include <epan/prefs.h>
+
+#define OPTO_FRAME_HEADER_LEN 8
+#define OPTOMMP_DEST_ID 0x0000
+#define OPTOMMP_RT 0x0
+#define OPTOMMP_HIGH_TCODE 0x7
+#define OPTOMMP_PRIORITY 0x0
+#define OPTOMMP_MIN_LENGTH 12
+#define OPTOMMP_MIN_HEURISTIC 0x4
+
+#define OPTOMMP_WRITE_QUADLET_REQUEST 0
+#define OPTOMMP_WRITE_BLOCK_REQUEST 1
+#define OPTOMMP_WRITE_RESPONSE 2
+#define OPTOMMP_READ_QUADLET_REQUEST 4
+#define OPTOMMP_READ_BLOCK_REQUEST 5
+#define OPTOMMP_READ_QUADLET_RESPONSE 6
+#define OPTOMMP_READ_BLOCK_RESPONSE 7
+
+/* Initialize the protocol and registered fields */
+static gint proto_optommp = -1;
+static dissector_handle_t optommp_tcp_handle;
+static dissector_handle_t optommp_udp_handle;
+static gint hf_optommp_tl = -1;
+static gint hf_optommp_tcode = -1;
+static gint hf_optommp_source_ID = -1;
+static gint hf_optommp_rcode = -1;
+static gint hf_optommp_quadlet_data = -1;
+static gint hf_optommp_data_length = -1;
+static gint hf_optommp_dest_offset  = -1;
+static gint hf_optommp_data_block_byte  = -1;
+static gint hf_optommp_data_block_quadlet  = -1;
+/* Initialize the subtree pointers */
+static gint ett_optommp = -1;
+static gint ett_data_block_q = -1;
+static gint ett_data_block_b = -1;
+/* PORT_PREF */
+static guint gOPTOMMP_PORT_PREF = 0;
+
+
+static const value_string optommp_tcode_names[] = {
+    { 0, "Write Quadlet Request" },
+    { 1, "Write Block Request" },
+    { 2, "Write Response" },
+    { 4, "Read Quadlet Request" },
+    { 5, "Read Block Request" },
+    { 6, "Read Quadlet Response" },
+    { 7, "Read Block Response" },
+    { 0, NULL }
+};
+
+static const value_string optommp_rcode_meanings[] = {
+    { 0x0, "No error" },
+    { 0x1, "Undefined command" },
+    { 0x2, "Invalid point type" },
+    { 0x3, "Invalid float" },
+    { 0x4, "Powerup Clear expected" },
+    { 0x5, "Invalid memory address/data" },
+    { 0x6, "Invalid command length" },
+    { 0x7, "Reserved" },
+    { 0x8, "Busy" },
+    { 0x9, "Cannot erase flash" },
+    { 0xa, "Cannot program flash" },
+    { 0xb, "Downloaded image too small" },
+    { 0xc, "Image CRC mismatch" },
+    { 0xd, "Image length mismatch" },
+    { 0xe, "Feature is not yet implemented" },
+    { 0xf, "Communications watchdog timeout" },
+    { 0, NULL }
+};
+
+static const range_string optommp_mm_areas[] = {
+    { 0xf0100000,   0xf01bffff,
+            "Expanded Analog & Digital Point Configuration - Read/Write" },
+    {   0xf01c0000, 0xf01c7fff,
+            "Expanded Analog Point Calc & Set - Read/Write" },
+    {   0xf01d4000, 0xf01dffff,
+            "Expanded Analog Point Read & Clear - Read/Write" },
+    {   0xf0260000, 0xf029ffff,
+            "Expanded Analog Point Read - Read" },
+    {   0xf02a0000, 0xf02dffff,
+            "Expanded Analog Point Write - Read/Write" },
+    {   0xf02e0000, 0xf02f7fff,
+            "Expanded Digital Point Read & Clear - Read/Write" },
+    {   0xf0300000, 0xf030024b,
+            "Status Area Read - Read Only" },
+    {   0xf0310400, 0xf031110f,
+            "Communications Port Configuration - Read/Write" },
+    {   0xf0329000, 0xf032efff,
+            "Serial Pass-Through - Read/Write" },
+    {   0xf0350000, 0xf0350023,
+            "Date and Time Configuration - Read/Write" },
+    {   0xf0380000, 0xf0380297,
+            "Status Area Write - Read/Write" },
+    {   0xf0390000, 0xf0390003,
+            "Modbus Configuration - Read/Write" },
+    {   0xf03a0004, 0xf03a0073,
+            "Network Security Configuration - Read/Write" },
+    {   0xf03a1000, 0xf03a1fff,
+            "SSI Module Configuration - Read/Write" },
+    {   0xf03a7f00, 0xf03a7ffa,
+            "Serial Module Identification - Read Only" },
+    {   0xf03a8000, 0xf03a840f,
+            "Serial Module Configuration - Read/Write" },
+    {   0xf03a8500, 0xf03a8dc3,
+            "Wiegand Serial Module Configuration - Read/Write" },
+    {   0xf03a9000, 0xf03a92bf,
+            "SNAP-SCM-CAN2B Serial Module Configuration -Read/Write" },
+    {   0xf03c0000, 0xf03c030b,
+            "SNMP Configuration - Read/Write" },
+    {   0xf03d0000, 0xf03d0079,
+            "FTP User Name/Password Configuration - Read/Write" },
+    {   0xf03e0000, 0xf03eb107,
+            "PPP Configuration - Read/Write" },
+    {   0xf03eb800, 0xf03fb827,
+            "PPP Status - Read Only" },
+    {   0xf03fffc4, 0xf03fffff,
+            "Streaming Configuration - Read/Write" },
+    {   0xf0400000, 0xf04001ff,
+            "Digital Bank Read - Read Only" },
+    {   0xf0500000, 0xf050001f,
+            "Digital Bank Write - Read/Write" },
+    {   0xf0600000, 0xf06003ff,
+            "Analog Bank Read - Read Only" },
+    {   0xf0700000, 0xf07001ff,
+            "Analog Bank Write - Read/Write" },
+    {   0xf0800000, 0xf0800fd3,
+            "Digital Point Read - Read Only" },
+    {   0xf0900000, 0xf0900fcf,
+            "Digital Point Write - Read/Write" },
+    {   0xf0a00000, 0xf0a00fcf,
+            "Old Analog Point Read - Read Only" },
+    {   0xf0b00000, 0xf0b00fcf,
+            "Old Analog Point Write - Read/Write" },
+    {   0xf0c00000, 0xf0c011ff,
+            "Old A&D Point Configuration Information - Read/Write" },
+    {   0xf0d00000, 0xf0d01fff,
+            "Old Digital Events and Reactions - Read/Write" },
+    {   0xf0d40000, 0xf0d4ffff,
+            "Digital Events - Expanded - Read/Write" },
+    {   0xf0d80000, 0xf0dc81ff,
+            "Scratch Pad - Read/Write" },
+    {   0xf0e00000, 0xf0e001ff,
+            "Old Analog Point Calculation and Set - Read Only" },
+    {   0xf0f00000, 0xf0f002ff,
+            "Old Digital Read and Clear - Read Only" },
+    {   0xf0f80000, 0xf0f801ff,
+            "Old Analog Read and Clear/Restart - Read Only" },
+    {   0xf1000000, 0xf100021f,
+            "Streaming - Read Only" },
+    {   0xf1001000, 0xf10017ff,
+            "Analog EU or Digital Counter Packed Data - Read" },
+    {   0xf1001800, 0xf100183f,
+            "Digital Packed Data - Read/Write" },
+    {   0xf1100000, 0xf1101fff,
+            "Alarm Event Settings - Read/Write" },
+    {   0xf1200000, 0xf12111ff,
+            "Event Message Configuration - Read/Write" },
+    {   0xf1300000, 0xf13000a3,
+            "Email Configuration - Read/Write" },
+    {   0xf1540000, 0xf1540efc,
+            "Serial Event Configuration - Read/Write" },
+    {   0xf1560000, 0xf1f60f7f,
+            "Wiegand Serial Event Configuration - Read/Write" },
+    {   0xf1808000, 0xf1809ffe,
+            "SNAP High-Density Digital - Read Only" },
+    {   0xf180a000, 0xf180bffe,
+            "SNAP High-Density Digital Read and Clear - Read/Write" },
+    {   0xf180c000, 0xf180c3fe,
+            "SNAP High-Density Digital Write - Read/Write" },
+    {   0xf2000000, 0xf2002edf,
+            "PID Configuration and Status - Read/Write" },
+    {   0xf2100000, 0xf21047ff,
+            "PID Configuration and Status - Read/Write" },
+    {   0xf3000000, 0xf3000707,
+            "Data Logging Configuration - Read/Write" },
+    {   0xf3020000, 0xf302176f,
+            "Data Log - Read/Write" },
+    {   0xf4000000, 0xf4000f6f,
+            "PID Module Configuration - Read/Write" },
+    {   0xf4080000, 0xf4080007,
+            "Control Engine - Read/Write" },
+    {   0xf7002000, 0xf7002103,
+            "Serial Brain Communication - Read/Write" },
+    {   0xf7002200, 0xf7002207,
+            "microSD Card - Read/Write" },
+    {   0xf7003000, 0xf700308f,
+            "WLAN Status - Read Only" },
+    {   0xf7004000, 0xf700553b,
+            "WLAN Configuration - Read/Write" },
+    {   0xf8000000, 0xf800000b,
+            "WLAN Enable - Read/Write" },
+    {   0xfffff008, 0xfffff077,
+            "IP Settings - Read/Write" },
+    {   0,          0,          NULL }
+};
+
+/* Function Prototypes */
+static guint get_optommp_message_len(packet_info *pinfo _U_, tvbuff_t *tvb,
+    gint offset);
+static gint dissect_optommp_reassemble_tcp(tvbuff_t *tvb, packet_info *pinfo,
+    proto_tree *tree, void *data);
+static gint dissect_optommp_reassemble_udp(tvbuff_t *tvb, packet_info *pinfo,
+    proto_tree *tree, void *data);
+static gint dissect_optommp(tvbuff_t *tvb, packet_info *pinfo, proto_tree
+    *tree, void * data _U_);
+static void dissect_optommp_write_quadlet_request(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_write_block_request(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_write_response(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_read_quadlet_request(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_read_block_request(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_read_quadlet_response(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_read_block_response(proto_item **ti, proto_tree
+    *tree, tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_source_ID(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_destination_offset_6(proto_item **ti,
+     proto_tree *tree, tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_quadlet_data(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_rcode(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset);
+static guint16 dissect_optommp_data_length(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_data_block(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset, guint16 data_length);
+static void dissect_optommp_data_block_byte(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset);
+static void dissect_optommp_data_block_quadlet(proto_item **ti, proto_tree
+    *tree, tvbuff_t *tvb, guint *poffset);
+static gint optommp_has_destination_offset(guint8 tcode);
+void proto_reg_handoff_optommp(void);
+
+/****************************************************************************
+function:       get_optommp_message_len()
+parameters:     pinfo: not used
+                tvb: poiner to packet data
+                offset: not used
+purpose:        Gets the message length depending on tcode and data_block len
+****************************************************************************/
+static guint get_optommp_message_len(packet_info *pinfo _U_, tvbuff_t *tvb,
+    gint offset)
+{
+    guint len = OPTO_FRAME_HEADER_LEN;
+    guint8 tcode = 0;
+
+    /* Just want the most significant nibble */
+    tcode = tvb_get_guint8(tvb, offset + 3) >> 4;
+
+    if( tcode == OPTOMMP_WRITE_QUADLET_REQUEST ||
+        tcode == OPTOMMP_WRITE_BLOCK_REQUEST ||
+        tcode == OPTOMMP_READ_BLOCK_REQUEST ||
+        tcode == OPTOMMP_READ_QUADLET_RESPONSE ||
+        tcode == OPTOMMP_READ_BLOCK_RESPONSE )
+    {
+        len = 16;
+    }
+    else if( tcode == OPTOMMP_WRITE_RESPONSE ||
+        tcode == OPTOMMP_READ_QUADLET_REQUEST )
+    {
+        len = 12;
+    }
+
+    if( (tcode == OPTOMMP_WRITE_BLOCK_REQUEST ||
+        tcode == OPTOMMP_READ_BLOCK_RESPONSE) &&
+        tvb_reported_length_remaining(tvb, offset) >= 14 )
+    {
+        /* offset + 12 is the data_length of the packet */
+        len += (guint) tvb_get_ntohs(tvb, offset + 12);
+    }
+
+    return len;
+}
+
+/****************************************************************************
+function:       dissect_optommp_reassemble_tcp()
+parameters:     void
+purpose:        reassemble packets then send to dissector
+****************************************************************************/
+static gint dissect_optommp_reassemble_tcp(tvbuff_t *tvb, packet_info *pinfo,
+    proto_tree *tree, void *data)
+{
+    tcp_dissect_pdus(tvb, pinfo, tree, TRUE, OPTO_FRAME_HEADER_LEN,
+        get_optommp_message_len, dissect_optommp, data);
+
+    return tvb_captured_length(tvb);
+}
+
+/****************************************************************************
+function:       dissect_optommp_reassemble_udp()
+parameters:     void
+purpose:        reassemble packets then send to dissector
+****************************************************************************/
+static gint dissect_optommp_reassemble_udp(tvbuff_t *tvb, packet_info *pinfo,
+    proto_tree *tree, void *data)
+{
+    dissect_optommp(tvb, pinfo, tree, data);
+
+    return tvb_captured_length(tvb);
+}
+
+/****************************************************************************
+function:       dissect_optommp()
+parameters:     void
+purpose:        add the optommp protocol subtree
+****************************************************************************/
+static gint dissect_optommp(tvbuff_t *tvb, packet_info *pinfo, proto_tree
+    *tree, void *data _U_)
+{
+    /* Declare and init variables for each part of the packet */
+    guint8 tcode = 0;
+
+    /* Provide a summary label */
+    col_set_str(pinfo->cinfo, COL_PROTOCOL, "OptoMMP");
+    col_clear(pinfo->cinfo, COL_INFO);
+    if( tvb_reported_length(tvb) >= OPTOMMP_MIN_LENGTH)
+    {
+        /* the tcode is the most sig nibble of the 3 byte */
+        tcode = tvb_get_guint8(tvb, 3) >> 4;
+        if( optommp_has_destination_offset(tcode) != 0 &&
+            tvb_reported_length(tvb) >= 12)
+        {
+            guint64 destination_offset = 0;
+            destination_offset = tvb_get_ntoh48(tvb, 6);
+            col_add_fstr(pinfo->cinfo, COL_INFO,
+                " type: %s, dest_off: 0x%012" G_GINT64_MODIFIER "x",
+                val_to_str(tcode, optommp_tcode_names, "Unknown (0x%02x)"),
+                destination_offset);
+        }
+        else
+        {
+            col_add_fstr(pinfo->cinfo, COL_INFO, " type: %s",
+                val_to_str(tcode, optommp_tcode_names, "Unknown (0x%02x)"));
+        }
+    }
+
+    if( tree )
+    {
+        proto_item *root_ti = NULL;
+        proto_item *ti = NULL;
+        proto_tree *optommp_tree = NULL;
+        guint offset = 0;
+
+        /* Add the root node of our protocol */
+        root_ti = proto_tree_add_item(tree, proto_optommp, tvb, 0, -1,
+            ENC_NA);
+        if( tvb_reported_length(tvb) >= OPTOMMP_MIN_LENGTH)
+        {
+            tcode = tvb_get_guint8(tvb, 3) >> 4;
+            proto_item_append_text(root_ti, ", type: %s", val_to_str(tcode,
+                optommp_tcode_names, "Unknown (0x%02x)"));
+            if( optommp_has_destination_offset(tcode) != 0 )
+            {
+                guint64 destination_offset = 0;
+                destination_offset = tvb_get_ntoh48(tvb, 6);
+                proto_item_append_text(root_ti,
+                    ", dest_off: 0x%012" G_GINT64_MODIFIER "x",
+                    destination_offset);
+            }
+            /* Add an expansion to the tree */
+            optommp_tree = proto_item_add_subtree(root_ti, ett_optommp);
+            /* Skip destination_ID */
+            offset += 2;
+            /* Dissect transaction label */
+            ti = proto_tree_add_item(optommp_tree, hf_optommp_tl, tvb, offset,
+                1, ENC_BIG_ENDIAN);
+            ++offset;
+            /* Dissect tcode */
+            proto_tree_add_item(optommp_tree, hf_optommp_tcode, tvb,
+                offset, 1, ENC_BIG_ENDIAN);
+            tcode = tvb_get_guint8(tvb, offset) >> 4;
+            ++offset;
+            /* Dissect the rest of the packet according to type */
+            switch( tcode )
+            {
+            case 0:
+                dissect_optommp_write_quadlet_request(&ti, optommp_tree, tvb,
+                    &offset);
+                break;
+            case 1:
+                dissect_optommp_write_block_request(&ti, optommp_tree, tvb,
+                    &offset);
+                break;
+            case 2:
+                dissect_optommp_write_response(&ti, optommp_tree, tvb,
+                    &offset);
+                break;
+            case 4:
+                dissect_optommp_read_quadlet_request(&ti, optommp_tree, tvb,
+                    &offset);
+                break;
+            case 5:
+                dissect_optommp_read_block_request(&ti, optommp_tree, tvb,
+                    &offset);
+                break;
+            case 6:
+                dissect_optommp_read_quadlet_response(&ti, optommp_tree, tvb,
+                    &offset);
+                break;
+            case 7:
+                dissect_optommp_read_block_response(&ti, optommp_tree, tvb,
+                    &offset);
+                break;
+            }
+        }
+    }
+
+    return tvb_captured_length(tvb);
+}
+
+/****************************************************************************
+function:       dissect_optommp_write_quadlet_request()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect a write quadlet request
+****************************************************************************/
+static void dissect_optommp_write_quadlet_request(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset)
+{
+    dissect_optommp_source_ID(ti, tree, tvb, poffset);
+    dissect_optommp_destination_offset_6(ti, tree, tvb, poffset);
+    dissect_optommp_quadlet_data(ti, tree, tvb, poffset);
+}
+
+/****************************************************************************
+function:       dissect_optommp_write_block_request()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect a write block request
+****************************************************************************/
+static void dissect_optommp_write_block_request(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset)
+{
+    guint16 data_length = 0;
+    dissect_optommp_source_ID(ti, tree, tvb, poffset);
+    dissect_optommp_destination_offset_6(ti, tree, tvb, poffset);
+    data_length = dissect_optommp_data_length(ti, tree, tvb, poffset);
+    *poffset += 2; /* skip extended_tcode */
+    dissect_optommp_data_block(ti, tree, tvb, poffset, data_length);
+}
+
+/****************************************************************************
+function:       dissect_optommp_write_response()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect a write response
+****************************************************************************/
+static void dissect_optommp_write_response(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset)
+{
+    dissect_optommp_source_ID(ti, tree, tvb, poffset);
+    dissect_optommp_rcode(ti, tree, tvb, poffset);
+}
+
+/****************************************************************************
+function:       dissect_optommp_read_quadlet_request()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect a read quadlet request
+****************************************************************************/
+static void dissect_optommp_read_quadlet_request(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset)
+{
+    dissect_optommp_source_ID(ti, tree, tvb, poffset);
+    dissect_optommp_destination_offset_6(ti, tree, tvb, poffset);
+}
+
+/****************************************************************************
+function:       dissect_optommp_read_block_request()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect a read block request
+****************************************************************************/
+static void dissect_optommp_read_block_request(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset)
+{
+    dissect_optommp_source_ID(ti, tree, tvb, poffset);
+    dissect_optommp_destination_offset_6(ti, tree, tvb, poffset);
+    dissect_optommp_data_length(ti, tree, tvb, poffset);
+}
+
+/****************************************************************************
+function:       dissect_optommp_read_quadlet_response
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect a read quadlet response
+****************************************************************************/
+static void dissect_optommp_read_quadlet_response(proto_item **ti,
+    proto_tree *tree, tvbuff_t *tvb, guint *poffset)
+{
+    dissect_optommp_source_ID(ti, tree, tvb, poffset);
+    dissect_optommp_rcode(ti, tree, tvb, poffset);
+    *poffset += 5; /* Skip reserved part for now */
+    dissect_optommp_quadlet_data(ti, tree, tvb, poffset);
+}
+
+/****************************************************************************
+function:       dissect_optommp_read_block_response()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect a read block response
+****************************************************************************/
+static void dissect_optommp_read_block_response(proto_item **ti, proto_tree
+    *tree, tvbuff_t *tvb, guint *poffset)
+{
+    guint16 data_length = 0;
+    dissect_optommp_source_ID(ti, tree, tvb, poffset);
+    dissect_optommp_rcode(ti, tree, tvb, poffset);
+    *poffset += 5; /* Skip the reserved part for now */
+    data_length = dissect_optommp_data_length(ti, tree, tvb, poffset);
+    *poffset += 2; /* skip extended_tcode */
+    dissect_optommp_data_block(ti, tree, tvb, poffset, data_length);
+}
+
+/****************************************************************************
+function:       dissect_optommp_source_ID()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect the source id field.
+****************************************************************************/
+static void dissect_optommp_source_ID(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset)
+{
+    if( tvb_reported_length(tvb) >= *poffset + 2 )
+    {
+        *ti = proto_tree_add_item(tree, hf_optommp_source_ID, tvb, *poffset,
+            2, ENC_BIG_ENDIAN);
+    }
+    *poffset += 2;
+}
+
+/****************************************************************************
+function:       dissect_optommp_destination_offset_6()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Get the destination offset byte by byte and then reassemble
+note:           This must be called when the reported length < offset + 8
+****************************************************************************/
+static void dissect_optommp_destination_offset_6(proto_item **ti,
+     proto_tree *tree, tvbuff_t *tvb, guint *poffset)
+{
+    if( tvb_reported_length(tvb) >= *poffset + 6 )
+    {
+        *poffset += 2; /* The first two bytes are always 0xFFFF */
+        *ti = proto_tree_add_item(tree, hf_optommp_dest_offset, tvb,
+            *poffset, 4, ENC_BIG_ENDIAN);
+    }
+    *poffset += 4;
+}
+
+/****************************************************************************
+function:       dissect_optommp_quadlet_data()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect the quadlet data part for packets that have it
+****************************************************************************/
+static void dissect_optommp_quadlet_data(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset)
+{
+    if( tvb_reported_length(tvb) >= *poffset + 4 )
+    {
+        *ti = proto_tree_add_item(tree, hf_optommp_quadlet_data, tvb,
+            *poffset, 4, ENC_BIG_ENDIAN);
+    }
+    *poffset += 4;
+}
+
+/****************************************************************************
+function:       dissect_optommp_data_length()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect data length
+****************************************************************************/
+static guint16 dissect_optommp_data_length(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset)
+{
+    guint16 data_length = 0;
+
+    if( tvb_reported_length(tvb) >= *poffset + 2 )
+    {
+        data_length = tvb_get_ntohs(tvb, *poffset);
+        *ti = proto_tree_add_item(tree, hf_optommp_data_length, tvb,
+            *poffset, 2, ENC_BIG_ENDIAN);
+    }
+
+    *poffset += 2;
+
+    return data_length;
+}
+
+/****************************************************************************
+function:       dissect_optommp_rcode()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect rcode part for packets that have it
+****************************************************************************/
+static void dissect_optommp_rcode(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset)
+{
+    if( tvb_reported_length(tvb) >= *poffset + 1 )
+    {
+        *ti = proto_tree_add_item(tree, hf_optommp_rcode, tvb, *poffset,
+            1, ENC_BIG_ENDIAN);
+    }
+
+    ++(*poffset);
+}
+
+/****************************************************************************
+function:       dissect_optommp_data_block()
+parameters:     ti:         The node to add the subtree to
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+                data_length:number of bytes in the data_block
+purpose:        Dissect a data block.
+****************************************************************************/
+static void dissect_optommp_data_block(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset, guint16 data_length)
+{
+    proto_tree *data_block_tree_b = NULL;
+    proto_tree *data_block_tree_q = NULL;
+    guint i = 0;
+    guint quadlet_offset = 0;
+    guint byte_offset = 0;
+    quadlet_offset = *poffset;
+    byte_offset = *poffset;
+
+    /* Create and fill quadlet subtree */
+    data_block_tree_q = proto_tree_add_subtree(tree, tvb, *poffset,
+        data_length, ett_data_block_q, ti, "data_block (as quadlets)");
+
+    for( i = 0; i < (guint16) (data_length / 4); ++i )
+    {
+        dissect_optommp_data_block_quadlet(ti, data_block_tree_q, tvb,
+            &quadlet_offset);
+    }
+
+    /* Create and fill byte subtree */
+    data_block_tree_b = proto_tree_add_subtree(tree, tvb, *poffset,
+        data_length, ett_data_block_b, ti, "data_block (as bytes)");
+
+    for( i = 0; i < data_length; ++i )
+    {
+        dissect_optommp_data_block_byte(ti, data_block_tree_b, tvb,
+            &byte_offset);
+    }
+}
+
+/****************************************************************************
+function:       dissect_optommp_data_block_byte()
+parameters:     ti:         Reserved for future use
+                tree:       The subtree to append nodes to
+                tvb:        The data of the current node
+                poffset:    Keeps track of our location in the tree
+purpose:        Dissect a data block.
+****************************************************************************/
+static void dissect_optommp_data_block_byte(proto_item **ti, proto_tree *tree,
+    tvbuff_t *tvb, guint *poffset)
+{
+    if( tvb_reported_length(tvb) >= *poffset + 1 )
+    {
+        GByteArray *unused_ret_val = NULL;
+        unused_ret_val = g_byte_array_new();
+        /* CheckAPI.pl complained when using ENC_BIG_ENDIAN as the sixth
+        *  parameter, so set it to 0x0 */
+        *ti = proto_tree_add_bytes_item(tree, hf_optommp_data_block_byte, tvb,
+            *poffset, 1, 0x0, unused_ret_val, NULL, NULL);
+        g_byte_array_free(unused_ret_val, TRUE);
+    }
+
+    ++(*poffset);
+}
+
+/****************************************************************************
+function:       dissect_optommp_data_block_quadlet()
+parameters:     ti:             Reserved for future use
+                tree:           The subtree to append nodes to
+                tvb:            The data of the current node
+                poffset:        Keeps track of our location in the tree
+purpose:        Dissect a data block.
+****************************************************************************/
+static void dissect_optommp_data_block_quadlet(proto_item **ti, proto_tree
+    *tree, tvbuff_t *tvb, guint *poffset)
+{
+    if( tvb_reported_length(tvb) >= *poffset + 4 )
+    {
+        *ti = proto_tree_add_item(tree, hf_optommp_data_block_quadlet,
+            tvb, *poffset, 4, ENC_NA);
+    }
+
+    *poffset += 4;
+}
+
+/****************************************************************************
+function:       dissect_optommp_data_block_quadlet()
+parameters:     ti:             Reserved for future use
+                tree:           The subtree to append nodes to
+                tvb:            The data of the current node
+                poffset:        Keeps track of our location in the tree
+returns:        1 if packet type has destination_offset field, 0 otherwise
+purpose:        Dissect a data block.
+****************************************************************************/
+static gint optommp_has_destination_offset(guint8 tcode)
+{
+    if( tcode == 0 || tcode == 1 || tcode == 4 || tcode == 5 )
+        return 1;
+
+    return 0;
+}
+
+/****************************************************************************
+function:       proto_register_optommp()
+parameters:     void
+purpose:        create and register the protocol, trees, and fields
+****************************************************************************/
+void proto_register_optommp(void)
+{
+    module_t *optommp_module;
+    /* The fields */
+    static hf_register_info hf[] =
+    {
+        { &hf_optommp_tl,
+            { "tl", "optommp.tl",
+            FT_UINT8, BASE_HEX,
+            NULL, 0xFC,
+            NULL, HFILL }
+        },
+        { &hf_optommp_tcode,
+            { "tcode", "optommp.tcode",
+            FT_UINT8, BASE_HEX,
+            VALS(optommp_tcode_names), 0xF0,
+            NULL, HFILL }
+        },
+        { &hf_optommp_source_ID,
+            { "source_ID", "optommp.source_id",
+            FT_UINT16, BASE_HEX,
+            NULL, 0x0,
+            NULL, HFILL }
+        },
+        { &hf_optommp_rcode,
+            { "rcode", "optommp.rcode",
+            FT_UINT8, BASE_HEX,
+            VALS(optommp_rcode_meanings), 0xF0,
+            NULL, HFILL }
+        },
+        { &hf_optommp_quadlet_data,
+            { "quadlet_data", "optommp.quadlet_data",
+            FT_UINT32, BASE_HEX,
+            NULL, 0x0,
+            NULL, HFILL }
+        },
+        { &hf_optommp_data_length,
+            { "data_length", "optommp.data_length",
+            FT_UINT16, BASE_HEX,
+            NULL, 0x0,
+            NULL, HFILL }
+        },
+        { &hf_optommp_dest_offset,
+            { "destination_offset", "optommp.destination_offset",
+            FT_UINT32, BASE_HEX | BASE_RANGE_STRING,
+            RVALS(optommp_mm_areas), 0x0,
+            NULL, HFILL }
+        },
+        { &hf_optommp_data_block_byte,
+            { "data_block_byte", "optommp.data_block_byte",
+            FT_BYTES, BASE_NONE,
+            NULL, 0x0,
+            NULL, HFILL }
+        },
+        { &hf_optommp_data_block_quadlet,
+            { "data_block_quadlet", "optommp.data_block_quadlet",
+            FT_BYTES, BASE_NONE,
+            NULL, 0x0,
+            NULL, HFILL }
+        }
+    };
+
+    /* The subtrees */
+    static gint *ett[] =
+    {
+        &ett_optommp,
+        &ett_data_block_q,
+        &ett_data_block_b
+    };
+    /* The protocol */
+    proto_optommp = proto_register_protocol(
+        "OptoMMP",
+        "OptoMMP",
+        "optommp");
+    proto_register_field_array(proto_optommp, hf, array_length(hf));
+    proto_register_subtree_array(ett, array_length(ett));
+    optommp_module = prefs_register_protocol(proto_optommp,
+        proto_reg_handoff_optommp);
+    prefs_register_uint_preference(optommp_module, "tcp.port",
+        "OptoMMP TCP Port", " OptoMMP TCP port if other than the default",
+        10, &gOPTOMMP_PORT_PREF);
+}
+
+/****************************************************************************
+function:       proto_reg_handoff()
+parameters:     void
+purpose:        plug into wireshark with a handle
+****************************************************************************/
+void proto_reg_handoff_optommp(void)
+{
+    static gboolean initialized = FALSE;
+    static gint currentPort;
+
+    if( !initialized )
+    {
+        optommp_tcp_handle = new_create_dissector_handle(
+            dissect_optommp_reassemble_tcp, proto_optommp);
+        optommp_udp_handle = new_create_dissector_handle(
+            dissect_optommp_reassemble_udp, proto_optommp);
+        initialized = TRUE;
+    }
+    else
+    {
+        dissector_delete_uint("tcp.port", currentPort, optommp_tcp_handle);
+        dissector_delete_uint("udp.port", currentPort, optommp_udp_handle);
+    }
+
+    currentPort = gOPTOMMP_PORT_PREF;
+    dissector_add_uint("tcp.port", currentPort, optommp_tcp_handle);
+    dissector_add_uint("udp.port", currentPort, optommp_udp_handle);
+}