Suppress invalid or non-meaningful statistics - for example, without

time stamps on all packets in a set, you can't determine the start and
end time of the packets in the set (even one timestampless packet throws
the determination off - was that packet before the first time-stamped or
after the last time-stamped packet, or between them?).

svn path=/trunk/; revision=41187

5 files changed, 296 insertions, 155 deletions

diff --git a/summary.c b/summary.c
index 221d76aace..134106221b 100644
--- a/summary.c
+++ b/summary.c
@@ -43,48 +43,67 @@ tally_frame_data(frame_data *cur_frame, summary_tally *sum_tally)
 {
   double cur_time;
 
-  cur_time = nstime_to_sec(&cur_frame->abs_ts);
-
-  if (cur_time < sum_tally->start_time) {
-    sum_tally->start_time = cur_time;
-  }
-  if (cur_time > sum_tally->stop_time){
-    sum_tally->stop_time = cur_time;
-  }
   sum_tally->bytes += cur_frame->pkt_len;
   if (cur_frame->flags.passed_dfilter){
-    if (sum_tally->filtered_count==0){
-	    sum_tally->filtered_start= cur_time;
-	    sum_tally->filtered_stop = cur_time;
-    } else {
-	    if (cur_time < sum_tally->filtered_start) {
-		    sum_tally->filtered_start = cur_time;
-	    }
-	    if (cur_time > sum_tally->filtered_stop) {
-		    sum_tally->filtered_stop = cur_time;
-	    }
-    }
     sum_tally->filtered_count++;
-    sum_tally->filtered_bytes += cur_frame->pkt_len ;
+    sum_tally->filtered_bytes += cur_frame->pkt_len;
   }
   if (cur_frame->flags.marked){
-    if (sum_tally->marked_count==0){
-	    sum_tally->marked_start= cur_time;
-	    sum_tally->marked_stop = cur_time;
-    } else {
-	    if (cur_time < sum_tally->marked_start) {
-		    sum_tally->marked_start = cur_time;
-	    }
-	    if (cur_time > sum_tally->marked_stop) {
-		    sum_tally->marked_stop = cur_time;
-	    }
-    }
     sum_tally->marked_count++;
-    sum_tally->marked_bytes += cur_frame->pkt_len ;
+    sum_tally->marked_bytes += cur_frame->pkt_len;
   }
   if (cur_frame->flags.ignored){
     sum_tally->ignored_count++;
   }
+
+  if (cur_frame->flags.has_ts) {
+    /* This packet has a time stamp. */
+    cur_time = nstime_to_sec(&cur_frame->abs_ts);
+
+    sum_tally->packet_count_ts++;
+    if (cur_time < sum_tally->start_time) {
+      sum_tally->start_time = cur_time;
+    }
+    if (cur_time > sum_tally->stop_time){
+      sum_tally->stop_time = cur_time;
+    }
+    if (cur_frame->flags.passed_dfilter){
+      sum_tally->filtered_count_ts++;
+      /*
+       * If we've seen one filtered packet, this is the first
+       * one.
+       */
+      if (sum_tally->filtered_count == 1){
+        sum_tally->filtered_start= cur_time;
+        sum_tally->filtered_stop = cur_time;
+      } else {
+        if (cur_time < sum_tally->filtered_start) {
+          sum_tally->filtered_start = cur_time;
+        }
+        if (cur_time > sum_tally->filtered_stop) {
+          sum_tally->filtered_stop = cur_time;
+        }
+      }
+    }
+    if (cur_frame->flags.marked){
+      sum_tally->marked_count_ts++;
+      /*
+       * If we've seen one marked packet, this is the first
+       * one.
+       */
+      if (sum_tally->marked_count == 1){
+        sum_tally->marked_start= cur_time;
+        sum_tally->marked_stop = cur_time;
+      } else {
+        if (cur_time < sum_tally->marked_start) {
+          sum_tally->marked_start = cur_time;
+        }
+        if (cur_time > sum_tally->marked_stop) {
+          sum_tally->marked_stop = cur_time;
+        }
+      }
+    }
+  }
 }
 
 void
@@ -95,14 +114,17 @@ summary_fill_in(capture_file *cf, summary_tally *st)
   guint32        framenum;
   wtapng_section_t* shb_inf;
 
+  st->packet_count_ts = 0;
   st->start_time = 0;
   st->stop_time = 0;
   st->bytes = 0;
   st->filtered_count = 0;
+  st->filtered_count_ts = 0;
   st->filtered_start = 0;
   st->filtered_stop = 0;
   st->filtered_bytes = 0;
   st->marked_count = 0;
+  st->marked_count_ts = 0;
   st->marked_start = 0;
   st->marked_stop = 0;
   st->marked_bytes = 0;
@@ -194,7 +216,7 @@ summary_fill_in_capture(capture_file *cf,capture_options *capture_opts, summary_
       iface.linktype = wtapng_if_descr.link_type;
       g_array_append_val(st->ifaces, iface);
     }
-	g_free(idb_info);
+    g_free(idb_info);
   }
 }
 #endif
diff --git a/summary.h b/summary.h
index ec7062aaa2..15a2aaaa9d 100644
--- a/summary.h
+++ b/summary.h
@@ -33,45 +33,48 @@ typedef struct iface_options_tag {
     char	*name;
     char	*descr;
     char	*cfilter;
-    guint64	drops;				/* number of packet drops */
+    guint64	drops;		/* number of packet drops */
     gboolean	drops_known;	/* TRUE if number of packet drops is known */
-    gboolean	has_snap;		/* TRUE if maximum capture packet length is known */
-    int		snap;				/* Maximum captured packet length */
-    int		linktype;			/* wiretap encapsulation type */
+    gboolean	has_snap;	/* TRUE if maximum capture packet length is known */
+    int		snap;		/* Maximum captured packet length */
+    int		linktype;	/* wiretap encapsulation type */
 } iface_options;
 
 typedef struct _summary_tally {
-    guint64	bytes;				/**< total bytes */
-    double	start_time;			/**< seconds, with msec resolution */
-    double	stop_time;			/**< seconds, with msec resolution */
+    guint64	bytes;			/**< total bytes */
+    double	start_time;		/**< seconds, with msec resolution */
+    double	stop_time;		/**< seconds, with msec resolution */
     double	elapsed_time;		/**< seconds, with msec resolution,
-								   includes time before first packet
-								   and after last packet */
-    int		marked_count;		/**< number of marked packets */
+					   includes time before first packet
+					   and after last packet */
+    guint32	marked_count;		/**< number of marked packets */
+    guint32	marked_count_ts;	/**< number of time-stamped marked packets */
     guint64	marked_bytes;		/**< total bytes in the marked packets */
     double 	marked_start;		/**< time in seconds, with msec resolution */
     double 	marked_stop;		/**< time in seconds, with msec resolution */
-    int		ignored_count;		/**< number of ignored packets */
-    int		packet_count;		/**< total number of packets in trace */
-    int		filtered_count;		/**< number of filtered packets */
+    guint32	ignored_count;		/**< number of ignored packets */
+    guint32	packet_count;		/**< total number of packets in trace */
+    guint32	packet_count_ts;	/**< total number of time-stamped packets in trace */
+    guint32	filtered_count;		/**< number of filtered packets */
+    guint32	filtered_count_ts;	/**< number of time-stamped filtered packets */
     guint64	filtered_bytes;		/**< total bytes in the filtered packets */
     double 	filtered_start;		/**< time in seconds, with msec resolution */
     double 	filtered_stop;		/**< time in seconds, with msec resolution */
     const char	*filename;
     gint64	file_length;		/**< file length in bytes */
-    int		file_type;			/**< wiretap file type */
-    int		encap_type;			/**< wiretap encapsulation type */
+    int		file_type;		/**< wiretap file type */
+    int		encap_type;		/**< wiretap encapsulation type */
     gboolean	has_snap;		/**< TRUE if maximum capture packet length is known */
-    int		snap;				/**< Maximum captured packet length */
-    gboolean    drops_known;	/**< TRUE if number of packet drops is known */
+    int		snap;			/**< Maximum captured packet length */
+    gboolean    drops_known;		/**< TRUE if number of packet drops is known */
     guint64     drops;			/**< number of packet drops */
     const char	*dfilter;		/**< display filter */
     gboolean    is_tempfile;
 	/* from SHB, use summary_fill_shb_inf() to get values */
-    gchar       *opt_comment;   /**< comment from SHB block */
-    gchar       *shb_hardware;  /**< Capture HW from SHB block */
-    gchar       *shb_os;        /**< The OS the capture was made on from SHB block */
-    gchar       *shb_user_appl; /**< The application that made the capture from SHB block */
+    gchar       *opt_comment;   	/**< comment from SHB block */
+    gchar       *shb_hardware;		/**< Capture HW from SHB block */
+    gchar       *shb_os;		/**< The OS the capture was made on from SHB block */
+    gchar       *shb_user_appl;		/**< The application that made the capture from SHB block */
     /* capture related, use summary_fill_in_capture() to get values */
     GArray	*ifaces;
     gboolean	legacy;
diff --git a/ui/gtk/gsm_map_summary.c b/ui/gtk/gsm_map_summary.c
index 6651a47661..01c3229a6c 100644
--- a/ui/gtk/gsm_map_summary.c
+++ b/ui/gtk/gsm_map_summary.c
@@ -90,7 +90,7 @@ void gsm_map_stat_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   /* initialize the tally */
   summary_fill_in(&cfile, &summary);
 
-  /* initial compututations */
+  /* initial computations */
   seconds = summary.stop_time - summary.start_time;
 
   sum_open_w = dlg_window_new("GSM MAP Statistics: Summary");  /* transient_for top_level */
@@ -138,12 +138,21 @@ void gsm_map_stat_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   gtk_container_add(GTK_CONTAINER(data_fr), data_box);
   gtk_widget_show(data_box);
 
-  /* seconds */
-  g_snprintf(string_buff, SUM_STR_MAX, "Elapsed time: %.3f seconds", summary.elapsed_time);
-  add_string_to_box(string_buff, data_box);
-
-  g_snprintf(string_buff, SUM_STR_MAX, "Between first and last packet: %.3f seconds", seconds);
-  add_string_to_box(string_buff, data_box);
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    /* seconds */
+    g_snprintf(string_buff, SUM_STR_MAX, "Elapsed time: %.3f seconds", summary.elapsed_time);
+    add_string_to_box(string_buff, data_box);
+
+    g_snprintf(string_buff, SUM_STR_MAX, "Between first and last packet: %.3f seconds", seconds);
+    add_string_to_box(string_buff, data_box);
+  }
 
   /* Packet count */
   g_snprintf(string_buff, SUM_STR_MAX, "Packet count: %i", summary.packet_count);
@@ -178,12 +187,21 @@ void gsm_map_stat_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   g_snprintf(string_buff, SUM_STR_MAX, "Total number of Invokes: %u", tot_invokes);
   add_string_to_box(string_buff, invoke_box);
 
-  /* Total number of invokes per second */
-  if (seconds)
-	g_snprintf(string_buff, SUM_STR_MAX, "Total number of Invokes per second: %.2f", tot_invokes/seconds);
-  else
-	g_snprintf(string_buff, SUM_STR_MAX, "Total number of Invokes per second: N/A");
-  add_string_to_box(string_buff, invoke_box);
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    /* Total number of invokes per second */
+    if (seconds)
+      g_snprintf(string_buff, SUM_STR_MAX, "Total number of Invokes per second: %.2f", tot_invokes/seconds);
+    else
+      g_snprintf(string_buff, SUM_STR_MAX, "Total number of Invokes per second: N/A");
+    add_string_to_box(string_buff, invoke_box);
+  }
 
   /* Total size of invokes */
   g_snprintf(string_buff, SUM_STR_MAX, "Total number of bytes for Invokes: %.0f", tot_invokes_size);
@@ -191,17 +209,26 @@ void gsm_map_stat_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
 
   /* Average size of invokes */
   if (tot_invokes)
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per Invoke: %.2f", tot_invokes_size/tot_invokes);
+    g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per Invoke: %.2f", tot_invokes_size/tot_invokes);
   else
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per Invoke: N/A");
+    g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per Invoke: N/A");
   add_string_to_box(string_buff, invoke_box);
 
-  /* Average size of invokes per second */
-  if (seconds)
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per second: %.2f", tot_invokes_size/seconds);
-  else
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per second: N/A");
-  add_string_to_box(string_buff, invoke_box);
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    /* Average size of invokes per second */
+    if (seconds)
+      g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per second: %.2f", tot_invokes_size/seconds);
+    else
+      g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per second: N/A");
+    add_string_to_box(string_buff, invoke_box);
+  }
 
   /* Return Results frame */
   rr_fr = gtk_frame_new("Return Results");
@@ -216,12 +243,21 @@ void gsm_map_stat_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   g_snprintf(string_buff, SUM_STR_MAX, "Total number of Return Results: %u", tot_rr);
   add_string_to_box(string_buff, rr_box);
 
-  /* Total number of return results per second */
-  if (seconds)
-	g_snprintf(string_buff, SUM_STR_MAX, "Total number of Return Results per second: %.2f", tot_rr/seconds);
-  else
-	g_snprintf(string_buff, SUM_STR_MAX, "Total number of Return Results per second: N/A");
-  add_string_to_box(string_buff, rr_box);
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    /* Total number of return results per second */
+    if (seconds)
+      g_snprintf(string_buff, SUM_STR_MAX, "Total number of Return Results per second: %.2f", tot_rr/seconds);
+    else
+      g_snprintf(string_buff, SUM_STR_MAX, "Total number of Return Results per second: N/A");
+    add_string_to_box(string_buff, rr_box);
+  }
 
   /* Total size of return results */
   g_snprintf(string_buff, SUM_STR_MAX, "Total number of bytes for Return Results: %.0f", tot_rr_size);
@@ -229,17 +265,26 @@ void gsm_map_stat_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
 
   /* Average size of return results */
   if (tot_rr)
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per Return Result: %.2f", tot_rr_size/tot_rr);
+    g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per Return Result: %.2f", tot_rr_size/tot_rr);
   else
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per Return Result: N/A");
+    g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per Return Result: N/A");
   add_string_to_box(string_buff, rr_box);
 
-  /* Average size of return results per second */
-  if (seconds)
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per second: %.2f", tot_rr_size/seconds);
-  else
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per second: N/A");
-  add_string_to_box(string_buff, rr_box);
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    /* Average size of return results per second */
+    if (seconds)
+      g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per second: %.2f", tot_rr_size/seconds);
+    else
+      g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per second: N/A");
+    add_string_to_box(string_buff, rr_box);
+  }
 
   /* Totals frame */
   tot_fr = gtk_frame_new("Totals");
@@ -254,30 +299,47 @@ void gsm_map_stat_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   g_snprintf(string_buff, SUM_STR_MAX, "Total number of GSM MAP messages: %u", tot_invokes + tot_rr);
   add_string_to_box(string_buff, tot_box);
 
-  if (seconds)
-	g_snprintf(string_buff, SUM_STR_MAX, "Total number of GSM MAP messages per second: %.2f",
-		(tot_invokes + tot_rr)/seconds);
-  else
-	g_snprintf(string_buff, SUM_STR_MAX, "Total number of GSM MAP messages per second: N/A");
-  add_string_to_box(string_buff, tot_box);
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    if (seconds)
+      g_snprintf(string_buff, SUM_STR_MAX, "Total number of GSM MAP messages per second: %.2f",
+                 (tot_invokes + tot_rr)/seconds);
+    else
+      g_snprintf(string_buff, SUM_STR_MAX, "Total number of GSM MAP messages per second: N/A");
+    add_string_to_box(string_buff, tot_box);
+  }
 
   g_snprintf(string_buff, SUM_STR_MAX, "Total number of bytes for GSM MAP messages: %.0f", tot_invokes_size + tot_rr_size);
   add_string_to_box(string_buff, tot_box);
 
   if (tot_invokes + tot_rr)
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per GSM MAP messages: %.2f",
-		(tot_invokes_size + tot_rr_size)/(tot_invokes + tot_rr));
+    g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per GSM MAP messages: %.2f",
+               (tot_invokes_size + tot_rr_size)/(tot_invokes + tot_rr));
   else
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per GSM MAP messages: N/A");
-  add_string_to_box(string_buff, tot_box);
-
-  if (seconds)
-	g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes second: %.2f",
-		(tot_invokes_size + tot_rr_size)/seconds);
-  else
-	  g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes second: N/A");
+    g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes per GSM MAP messages: N/A");
   add_string_to_box(string_buff, tot_box);
 
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    if (seconds)
+      g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes second: %.2f",
+                 (tot_invokes_size + tot_rr_size)/seconds);
+    else
+      g_snprintf(string_buff, SUM_STR_MAX, "Average number of bytes second: N/A");
+    add_string_to_box(string_buff, tot_box);
+  }
 
   /* Button row. */
   bbox = dlg_button_row_new(GTK_STOCK_CLOSE, NULL);
diff --git a/ui/gtk/mtp3_summary.c b/ui/gtk/mtp3_summary.c
index 6afa783296..770d3ccbe8 100644
--- a/ui/gtk/mtp3_summary.c
+++ b/ui/gtk/mtp3_summary.c
@@ -286,7 +286,7 @@ void mtp3_sum_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   /* initialize the tally */
   summary_fill_in(&cfile, &summary);
 
-  /* initial compututations */
+  /* initial computations */
   seconds = summary.stop_time - summary.start_time;
 
   sum_open_w = dlg_window_new("MTP3 Statistics: Summary");  /* transient_for top_level */
@@ -335,12 +335,21 @@ void mtp3_sum_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   gtk_container_add(GTK_CONTAINER(data_fr), data_box);
   gtk_widget_show(data_box);
 
-  /* seconds */
-  g_snprintf(string_buff, SUM_STR_MAX, "Elapsed time: %.3f seconds", summary.elapsed_time);
-  add_string_to_box(string_buff, data_box);
-
-  g_snprintf(string_buff, SUM_STR_MAX, "Between first and last packet: %.3f seconds", seconds);
-  add_string_to_box(string_buff, data_box);
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    /* seconds */
+    g_snprintf(string_buff, SUM_STR_MAX, "Elapsed time: %.3f seconds", summary.elapsed_time);
+    add_string_to_box(string_buff, data_box);
+
+    g_snprintf(string_buff, SUM_STR_MAX, "Between first and last packet: %.3f seconds", seconds);
+    add_string_to_box(string_buff, data_box);
+  }
 
   /* Packet count */
   g_snprintf(string_buff, SUM_STR_MAX, "Packet count: %i", summary.packet_count);
@@ -351,7 +360,7 @@ void mtp3_sum_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   gtk_container_add(GTK_CONTAINER(main_vb), table_fr);
   gtk_widget_show(table_fr);
 
-   table = create_list();
+  table = create_list();
 
   gtk_container_add(GTK_CONTAINER(table_fr), table);
   gtk_widget_show(table);
@@ -371,32 +380,50 @@ void mtp3_sum_gtk_sum_cb(GtkAction *action _U_, gpointer user_data _U_)
   g_snprintf(string_buff, SUM_STR_MAX, "Total MSUs: %u", tot_num_msus);
   add_string_to_box(string_buff, tot_box);
 
-  if (seconds) {
-		g_snprintf(string_buff, SUM_STR_MAX, "MSUs/second: %.2f", tot_num_msus/seconds);
-  }
-  else {
-		g_snprintf(string_buff, SUM_STR_MAX, "MSUs/second: N/A");
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    if (seconds) {
+      g_snprintf(string_buff, SUM_STR_MAX, "MSUs/second: %.2f", tot_num_msus/seconds);
+    }
+    else {
+      g_snprintf(string_buff, SUM_STR_MAX, "MSUs/second: N/A");
+    }
+    add_string_to_box(string_buff, tot_box);
   }
-  add_string_to_box(string_buff, tot_box);
 
   g_snprintf(string_buff, SUM_STR_MAX, "Total Bytes: %.0f", tot_num_bytes);
   add_string_to_box(string_buff, tot_box);
 
   if (tot_num_msus) {
-		g_snprintf(string_buff, SUM_STR_MAX, "Average Bytes/MSU: %.2f", tot_num_bytes/tot_num_msus);
+    g_snprintf(string_buff, SUM_STR_MAX, "Average Bytes/MSU: %.2f", tot_num_bytes/tot_num_msus);
   }
   else {
-	    g_snprintf(string_buff, SUM_STR_MAX, "Average Bytes/MSU: N/A");
+    g_snprintf(string_buff, SUM_STR_MAX, "Average Bytes/MSU: N/A");
   }
   add_string_to_box(string_buff, tot_box);
 
-  if (seconds) {
-	  g_snprintf(string_buff, SUM_STR_MAX, "Bytes/second: %.2f", tot_num_bytes/seconds);
-  }
-  else {
-	  g_snprintf(string_buff, SUM_STR_MAX, "Bytes/second: N/A");
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least two time-stamped packets, in order for the elapsed
+   * time to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count_ts >= 2) {
+    if (seconds) {
+      g_snprintf(string_buff, SUM_STR_MAX, "Bytes/second: %.2f", tot_num_bytes/seconds);
+    }
+    else {
+      g_snprintf(string_buff, SUM_STR_MAX, "Bytes/second: N/A");
+    }
+    add_string_to_box(string_buff, tot_box);
   }
-  add_string_to_box(string_buff, tot_box);
 
   /* Button row. */
   bbox = dlg_button_row_new(GTK_STOCK_CLOSE, NULL);
diff --git a/ui/gtk/summary_dlg.c b/ui/gtk/summary_dlg.c
index 87f8a83424..055f5c2390 100644
--- a/ui/gtk/summary_dlg.c
+++ b/ui/gtk/summary_dlg.c
@@ -170,6 +170,14 @@ summary_open_cb(GtkWidget *w _U_, gpointer d _U_)
 #ifdef HAVE_LIBPCAP
   summary_fill_in_capture(&cfile, &global_capture_opts, &summary);
 #endif
+  /*
+   * Note: the start and stop times are initialized to 0, so if we
+   * have zero or one packets of the type in question that have
+   * time stamps, the elapsed times will be zero, just as if we
+   * have both start and stop time stamps but they're the same.
+   * That means we can avoid some checks for whether we have more
+   * than one packet of the type in question with time stamps.
+   */
   seconds = summary.stop_time - summary.start_time;
   disp_seconds = summary.filtered_stop - summary.filtered_start;
   marked_seconds = summary.marked_stop - summary.marked_start;
@@ -214,30 +222,43 @@ summary_open_cb(GtkWidget *w _U_, gpointer d _U_)
     add_string_to_table(table, &row, "Packet size limit:", string_buff);
   }
 
-
-  /* Time */
-  add_string_to_table(table, &row, "", "");
-  add_string_to_table(table, &row, "Time", "");
-
-  /* start time */
-  time_to_string(string_buff, SUM_STR_MAX, (time_t)summary.start_time);
-  add_string_to_table(table, &row, "First packet:", string_buff);
-
-  /* stop time */
-  time_to_string(string_buff, SUM_STR_MAX, (time_t)summary.stop_time);
-  add_string_to_table(table, &row, "Last packet:", string_buff);
-
-  /* elapsed seconds */
-  elapsed_time = (unsigned int)summary.elapsed_time;
-  if(elapsed_time/86400) {
-      g_snprintf(string_buff, SUM_STR_MAX, "%02u days %02u:%02u:%02u",
-        elapsed_time/86400, elapsed_time%86400/3600, elapsed_time%3600/60, elapsed_time%60);
-  } else {
-      g_snprintf(string_buff, SUM_STR_MAX, "%02u:%02u:%02u",
-        elapsed_time%86400/3600, elapsed_time%3600/60, elapsed_time%60);
+  /*
+   * We must have no un-time-stamped packets (i.e., the number of
+   * time-stamped packets must be the same as the number of packets),
+   * and at least one time-stamped packet, in order for the start
+   * and stop times to be valid.
+   */
+  if (summary.packet_count_ts == summary.packet_count &&
+      summary.packet_count >= 1) {
+    /* Time */
+    add_string_to_table(table, &row, "", "");
+    add_string_to_table(table, &row, "Time", "");
+
+    /* start time */
+    time_to_string(string_buff, SUM_STR_MAX, (time_t)summary.start_time);
+    add_string_to_table(table, &row, "First packet:", string_buff);
+
+    /* stop time */
+    time_to_string(string_buff, SUM_STR_MAX, (time_t)summary.stop_time);
+    add_string_to_table(table, &row, "Last packet:", string_buff);
+
+    /*
+     * We must have at least two time-stamped packets for the elapsed time
+     * to be valid.
+     */
+    if (summary.packet_count_ts >= 2) {
+      /* elapsed seconds */
+      elapsed_time = (unsigned int)summary.elapsed_time;
+      if(elapsed_time/86400) {
+          g_snprintf(string_buff, SUM_STR_MAX, "%02u days %02u:%02u:%02u",
+            elapsed_time/86400, elapsed_time%86400/3600, elapsed_time%3600/60, elapsed_time%60);
+      } else {
+          g_snprintf(string_buff, SUM_STR_MAX, "%02u:%02u:%02u",
+            elapsed_time%86400/3600, elapsed_time%3600/60, elapsed_time%60);
+      }
+      add_string_to_table(table, &row, "Elapsed:", string_buff);
+    }
   }
-  add_string_to_table(table, &row, "Elapsed:", string_buff);
-
 
   /* Capture */
   add_string_to_table(table, &row, "", "");
@@ -395,7 +416,8 @@ summary_open_cb(GtkWidget *w _U_, gpointer d _U_)
   } else {
     string_buff3[0] = '\0';
   }
-  add_string_to_list(list, "Between first and last packet", string_buff, string_buff2, string_buff3);
+  if (string_buff[0] != '\0' || string_buff2[0] != '\0' || string_buff3[0] != '\0')
+    add_string_to_list(list, "Between first and last packet", string_buff, string_buff2, string_buff3);
 
   /* Packets per second */
   if (seconds > 0) {
@@ -413,6 +435,7 @@ summary_open_cb(GtkWidget *w _U_, gpointer d _U_)
   } else {
     string_buff3[0] = '\0';
   }
+  if (string_buff[0] != '\0' || string_buff2[0] != '\0' || string_buff3[0] != '\0')
   add_string_to_list(list, "Avg. packets/sec", string_buff, string_buff2, string_buff3);
 
   /* Packet size */
@@ -437,7 +460,8 @@ summary_open_cb(GtkWidget *w _U_, gpointer d _U_)
   } else {
     string_buff3[0] = '\0';
   }
-  add_string_to_list(list, "Avg. packet size", string_buff, string_buff2, string_buff3);
+  if (string_buff[0] != '\0' || string_buff2[0] != '\0' || string_buff3[0] != '\0')
+    add_string_to_list(list, "Avg. packet size", string_buff, string_buff2, string_buff3);
 
   /* Byte count */
   g_snprintf(string_buff, SUM_STR_MAX, "%" G_GINT64_MODIFIER "u", summary.bytes);
@@ -451,7 +475,8 @@ summary_open_cb(GtkWidget *w _U_, gpointer d _U_)
   } else {
     string_buff3[0] = '\0';
   }
-  add_string_to_list(list, "Bytes", string_buff, string_buff2, string_buff3);
+  if (string_buff[0] != '\0' || string_buff2[0] != '\0' || string_buff3[0] != '\0')
+    add_string_to_list(list, "Bytes", string_buff, string_buff2, string_buff3);
 
   /* Bytes per second */
   if (seconds > 0){
@@ -472,7 +497,8 @@ summary_open_cb(GtkWidget *w _U_, gpointer d _U_)
   } else {
     string_buff3[0] = '\0';
   }
-  add_string_to_list(list, "Avg. bytes/sec", string_buff, string_buff2, string_buff3);
+  if (string_buff[0] != '\0' || string_buff2[0] != '\0' || string_buff3[0] != '\0')
+    add_string_to_list(list, "Avg. bytes/sec", string_buff, string_buff2, string_buff3);
 
   /* MBit per second */
   if (seconds > 0) {
@@ -496,7 +522,8 @@ summary_open_cb(GtkWidget *w _U_, gpointer d _U_)
   } else {
     string_buff3[0] = '\0';
   }
-  add_string_to_list(list, "Avg. MBit/sec", string_buff, string_buff2, string_buff3);
+  if (string_buff[0] != '\0' || string_buff2[0] != '\0' || string_buff3[0] != '\0')
+    add_string_to_list(list, "Avg. MBit/sec", string_buff, string_buff2, string_buff3);
 
 
   /* Button row. */