Wireshark-dev: Re: [Wireshark-dev] preliminary code submission
From: Brian Oleksa <[email protected]>
Date: Wed, 03 Feb 2010 15:21:27 -0500
Jakub

Yes...you are right. I am not using alot of those variables. I was mislead by what I was doing before I started to use the built in routines. :-)
My code base keeps getting smaller and smaller. I do understand that 
code quality / readability is a key factor in this industry. I still 
need to fix my IDE to get the correct formatting.
Perhaps once last quick look..?? Attached is the updated file.

Thanks again for the great feedback..!!

Brian





Jakub Zawadzki wrote:
Hi,

On Wed, Feb 03, 2010 at 01:05:32PM -0500, Brian Oleksa wrote:
Jakub

Thanks for this feedback. It is always good to have an extra set of eyes :-)
You missunderstood my comment about check_col()

instead of:
    if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_TAG_HELEN); if (check_col(pinfo->cinfo, COL_INFO))
        col_clear(pinfo->cinfo, COL_INFO);

Just write:
col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_TAG_HELEN); col_clear(pinfo->cinfo, COL_INFO);
  
gfloat latitude;
latitude = tvb_get_ntohieee_float(tvb,offset);

Why do you think this variable is not being used..??
Well because it's not used :) What is used for?

And one more thing...

You declare: ett_helen_ipv6, ett_helen_nos, ...
I believe you need only ett_helen from ett_*

Cheers.
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <glib.h>
#include <epan/packet.h>
#include <time.h>
#include <string.h>

#define PROTO_TAG_HELEN    "HELEN"

static int proto_helen = -1;

static dissector_handle_t helen_handle;

void dissect_helen(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);

static int helen_port = 7636;
static const char *mon_names[12] = {"Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"};

static gint hf_helen_magic = -1;
static gint hf_helen_checksum = -1;
static gint hf_helen_txTime = -1;

static gint hf_helen = -1;
static gint hf_helen_time = -1;
static gint hf_helen_ipv4 = -1;
static gint hf_helen_ipv6 = -1;
static gint hf_helen_nos = -1;
static gint hf_helen_flowname = -1;
static gint hf_helen_longitude = -1;
static gint hf_helen_latitude = -1;
static gint hf_helen_altitude = -1;
static gint hf_helen_bearing = -1;
static gint hf_helen_speed = -1;
static gint hf_helen_sequence_num = -1;
static gint hf_helen_gpsstatus = -1;
static gint hf_helen_source = -1;

static gint ett_helen = -1;

void proto_reg_handoff_helen(void) {
    static gboolean initialized = FALSE;

        if (!initialized) {
            helen_handle = create_dissector_handle(dissect_helen, proto_helen);
            dissector_add("udp.port", helen_port, helen_handle);
        }
    initialized = TRUE;
}

void proto_register_helen(void) {
    static hf_register_info hf[] = {
        { &hf_helen,
            { "Data", "helen.data", FT_NONE, BASE_NONE, NULL, 0x0,
                "HELEN PDU", HFILL}},
        { &hf_helen_magic,
            { "Magic Number", "helen.magicNumber", FT_UINT8, BASE_HEX, NULL, 0x0,
                "Magic Number", HFILL}},
        { &hf_helen_checksum,
           { "Checksum", "helen.checksum", FT_UINT64, BASE_DEC, NULL, 0x0,
                "Checksum", HFILL}},
        { &hf_helen_txTime,
            { "System Tx Time", "helen.SystemTxTime", FT_ABSOLUTE_TIME, BASE_NONE, NULL, 0x0,
                "System Tx Time", HFILL}},
        { &hf_helen_time,
	        { "Time", "helen.time", FT_ABSOLUTE_TIME, BASE_NONE, NULL, 0x0,
	            "Time", HFILL}},
	    { &hf_helen_ipv4,
			{ "IPv4", "helen.ipv4address", FT_IPv4, BASE_NONE, NULL, 0x0,
	            "IPv4", HFILL}},
	    { &hf_helen_ipv6,
			{ "IPv6", "helen.ipv6address", FT_IPv6, BASE_NONE, NULL, 0x0,
	            "IPv6", HFILL}},
        { &hf_helen_sequence_num,
			{ "Sequence Number", "helen.sequenceNumber", FT_UINT32, BASE_DEC, NULL, 0x0,
                "Sequence Number", HFILL}},
        { &hf_helen_source,
			{ "Source", "helen.source", FT_UINT32, BASE_DEC, NULL, 0x0,
                "Source", HFILL}},
        { &hf_helen_nos,
			{ "Number of Satellites", "helen.numberOfSatellites", FT_UINT8, BASE_DEC, NULL, 0x0,
			"Number of satellites", HFILL}},
		{ &hf_helen_flowname,
			{ "Flowname", "helen.flowname", FT_STRING, BASE_NONE, NULL, 0x0,
			"Flowname", HFILL}},
		{ &hf_helen_gpsstatus,
			{ "GPS Status", "helen.gpsStatus", FT_STRING, BASE_NONE, NULL, 0x0,
			"GPS Status", HFILL}},
		{ &hf_helen_longitude,
			{ "Longitude", "helen.longitude", FT_FLOAT, BASE_DEC, NULL, 0x0,
			"Longitude", HFILL}},
		{ &hf_helen_latitude,
			{ "Latitude", "helen.latitude", FT_FLOAT, BASE_DEC, NULL, 0x0,
			"Latitude", HFILL}},
		{ &hf_helen_altitude,
			{ "Altitude", "helen.altitude", FT_FLOAT, BASE_DEC, NULL, 0x0,
			"Altitude", HFILL}},
		{ &hf_helen_bearing,
			{ "Bearing", "helen.bearing", FT_FLOAT, BASE_DEC, NULL, 0x0,
			"Bearing", HFILL}},
		{ &hf_helen_speed,
			{ "Speed", "helen.speed", FT_FLOAT, BASE_DEC, NULL, 0x0,
			"Speed", HFILL}},
    };

    static gint * ett[] = {&ett_helen};

    proto_helen = proto_register_protocol("HELEN", "HELEN", "helen");
    proto_register_field_array(proto_helen, hf, array_length(hf));
    proto_register_subtree_array(ett, array_length(ett));
    register_dissector("helen", dissect_helen, proto_helen);
}

void dissect_helen(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {

    proto_item *helen_item = NULL;
    proto_item *helen_sub_item = NULL;
    proto_tree *helen_tree = NULL;
    proto_tree *helen_header_tree = NULL;

	col_set_str(pinfo->cinfo, COL_PROTOCOL, PROTO_TAG_HELEN);
    col_clear(pinfo->cinfo, COL_INFO);

    if (tree) {
        guint32 offset = 0;
        guint32 orig_offset = 18;
        nstime_t t;
		guint64 msecs_since_the_epoch;
		struct tm *tmp;
        helen_item = proto_tree_add_item(tree, proto_helen, tvb, 0, -1, FALSE);
        helen_tree = proto_item_add_subtree(helen_item, ett_helen);
        helen_header_tree = proto_item_add_subtree(helen_item, ett_helen);
        helen_sub_item = proto_tree_add_item(helen_tree, hf_helen_magic, tvb, offset, 2, FALSE);
        offset += 2;
		helen_sub_item = proto_tree_add_item(helen_tree, hf_helen_checksum, tvb, offset, 8, FALSE);
		offset += 8;

		msecs_since_the_epoch = tvb_get_ntoh64(tvb, offset);
		t.secs = msecs_since_the_epoch/1000;
		t.nsecs = (msecs_since_the_epoch%1000)*1000000;	/* milliseconds to nanoseconds */
		tmp = gmtime(&t.secs);
        proto_tree_add_time_format(helen_tree, hf_helen_txTime, tvb, offset, 8, &t,
            "Date: %s %2d, %d %02d:%02d:%02d UTC",mon_names[tmp->tm_mon],tmp->tm_mday,
			tmp->tm_year + 1900,tmp->tm_hour,tmp->tm_min,tmp->tm_sec,(long)t.nsecs);

        helen_header_tree = proto_item_add_subtree(helen_sub_item, ett_helen);
        {
            #define MAX_BUFFER 100
			char *buf = (char*)ep_alloc(MAX_BUFFER);
            char * packet_name = "";
            proto_tree *helen_sub_tree = NULL;
            offset = 18;

            for (;;) {
                guint16 code;
                guint16 numBytes = 0;
                guint unknownPacket = 0;
                guint codeOffset;
                offset = orig_offset;
		    	code = tvb_get_ntohs(tvb, offset);
                codeOffset = offset;
                offset += 2;
                numBytes = tvb_get_ntohs(tvb, offset);
                offset += 2;

                switch (code) {
                    case 0: packet_name = "End of Packet";
                        break;
                    case 1: packet_name = "GPS Extension";
                        break;
                    case 2: packet_name = "Flow Extension";
                        break;
                    case 3: packet_name = "Host Extension";
                        break;
                    default: packet_name = "Unknown code";
                        unknownPacket = 1;
                        break;
                }

                g_snprintf(buf, MAX_BUFFER, "%s", packet_name);

                if (unknownPacket) {
                    g_snprintf(buf, MAX_BUFFER, "Unknown packet: %d", code);
                }
                helen_item = proto_tree_add_text(tree, tvb, codeOffset, 2, "%s", buf);
                helen_sub_tree = proto_item_add_subtree(helen_item, ett_helen);

                if (code == 0) {
                    break;
                }

                /* GPS: */
                if (code == 1) {
                    guint8 fieldsAvail;
                    fieldsAvail = tvb_get_guint8(tvb, offset);
                    offset += 1;

                    /* Status: */
                    if ((fieldsAvail & 1) != 0) {
                        guint8 status;
                        char * statusStr = "";
                        status = tvb_get_guint8(tvb,offset);
                        if (status == 0) {
                            statusStr = "Good";
                        } else if (status == 1) {
                            statusStr = "No Fix";
                        } else if (status == 2) {
                            statusStr = "Bad GPS Read";
                        }
                        proto_tree_add_string_format(helen_sub_tree, hf_helen_gpsstatus, tvb, offset, 1, statusStr,
                                "GPS Status: %s", statusStr);
                        offset += 1;
                    }

                    /* Time: */
                    if ((fieldsAvail & 2) != 0) {
						nstime_t t;
						guint64 msecs_since_the_epoch;
						struct tm *tmp;
					    msecs_since_the_epoch = tvb_get_ntoh64(tvb, offset);
						t.secs = msecs_since_the_epoch/1000;
						t.nsecs = (msecs_since_the_epoch%1000)*1000000;	/* milliseconds to nanoseconds */
						tmp = gmtime(&t.secs);
                        proto_tree_add_time_format(helen_sub_tree, hf_helen_time, tvb, offset, 8, &t,
                                "Date: %s %2d, %d %02d:%02d:%02d UTC",mon_names[tmp->tm_mon],tmp->tm_mday,
								tmp->tm_year + 1900,tmp->tm_hour,tmp->tm_min,tmp->tm_sec,(long)t.nsecs);
                        offset += 8;
                    }

                    /* Longitude: */
                    if ((fieldsAvail & 4) != 0) {
                        proto_tree_add_item(helen_sub_tree, hf_helen_longitude, tvb, offset, 4, FALSE);
                        offset += 4;
                    }

                    /* Latitude: */
                    if ((fieldsAvail & 8) != 0) {
                        proto_tree_add_item(helen_sub_tree, hf_helen_latitude, tvb, offset, 4, FALSE);
                        offset += 4;
                    }

                    /* Altitude: */
                    if ((fieldsAvail & 16) != 0) {
                        proto_tree_add_item(helen_sub_tree, hf_helen_altitude, tvb, offset, 4, FALSE);
                        offset += 4;
                    }

                    /* Bearing: */
                    if ((fieldsAvail & 32) != 0) {
                        proto_tree_add_item(helen_sub_tree, hf_helen_bearing, tvb, offset, 4, FALSE);
                        offset += 4;
                    }

                    /* Speed: */
                    if ((fieldsAvail & 64) != 0) {
                        gfloat speed;
                        speed = tvb_get_ntohieee_float(tvb,offset);;
                        if (speed != 0.0) {
							proto_tree_add_item(helen_sub_tree, hf_helen_speed, tvb, offset, 4, FALSE);
                        }
                        offset += 4;
                    }

                    /* Number of Satellites: */
                    if ((fieldsAvail & 128) != 0) {
                        proto_tree_add_item(helen_sub_tree, hf_helen_nos, tvb, offset, 1, FALSE);
                        offset += 1;
                    }
                }

                /* FLOW: */
                if (code == 2) {
                    proto_tree_add_item(helen_sub_tree, hf_helen_flowname, tvb, offset, 8, FALSE);
                    offset += 8;

                    /* Sequence number: */
        			proto_tree_add_item(helen_sub_tree, hf_helen_sequence_num, tvb, offset, 4, FALSE);
                    offset += 4;

                    if (numBytes == 16) {
					   /* Source: */
					   proto_tree_add_item(helen_sub_tree, hf_helen_source, tvb, offset, 4, FALSE);
					   offset += 4;
                    }
                }

                /* HOST: */
                if (code == 3) {
                    /* Size: */
                    guint8 size;
                    size = tvb_get_guint8(tvb, offset);
                    offset += 1;

                    if (size == 4) {
                        proto_tree_add_item(helen_sub_tree, hf_helen_ipv4, tvb, offset, 4, FALSE);
                        offset += 4;
                    } else
                    {
						proto_tree_add_item(helen_sub_tree, hf_helen_ipv6, tvb, offset, 16, FALSE);
						offset += 16;
					}
			    }
                orig_offset += numBytes + 4;
            }
        }
    }
}