epan: Use hash table for dependent frames

Dependent frames list order does not matter and thus significantly
faster data structure can be used. Replace the list with hash table to
avoid excessive CPU usage when opening files containing reassembled
packets consisting of large number of fragments.

epan/frame_data.c

@@ -300,7 +300,7 @@ frame_data_reset(frame_data *fdata)
   }
 
   if (fdata->dependent_frames) {
-    g_slist_free(fdata->dependent_frames);
+    g_hash_table_destroy(fdata->dependent_frames);
     fdata->dependent_frames = NULL;
   }
 }
@@ -314,7 +314,7 @@ frame_data_destroy(frame_data *fdata)
   }
 
   if (fdata->dependent_frames) {
-    g_slist_free(fdata->dependent_frames);
+    g_hash_table_destroy(fdata->dependent_frames);
     fdata->dependent_frames = NULL;
   }
 }

epan/frame_data.h

@@ -71,7 +71,7 @@ typedef struct _frame_data {
      LLP64 (64-bit Windows) platforms.  Put them here, one after the
      other, so they don't require padding between them. */
   GSList      *pfd;          /**< Per frame proto data */
-  GSList      *dependent_frames;     /**< A list of frames which this one depends on */
+  GHashTable  *dependent_frames;     /**< A hash table of frames which this one depends on */
   const struct _color_filter *color_filter;  /**< Per-packet matching color_filter_t object */
   guint16      subnum;       /**< subframe number, for protocols that require this */
   /* Keep the bitfields below to 16 bits, so this plus the previous field

epan/frame_data_sequence.c

@@ -312,10 +312,10 @@ free_frame_data_sequence(frame_data_sequence *fds)
 }
 
 void
-find_and_mark_frame_depended_upon(gpointer data, gpointer user_data)
+find_and_mark_frame_depended_upon(gpointer key, gpointer value _U_, gpointer user_data)
 {
   frame_data   *dependent_fd;
-  guint32       dependent_frame = GPOINTER_TO_UINT(data);
+  guint32       dependent_frame = GPOINTER_TO_UINT(key);
   frame_data_sequence *frames   = (frame_data_sequence *)user_data;
 
   if (dependent_frame && frames) {
@@ -325,7 +325,9 @@ find_and_mark_frame_depended_upon(gpointer data, gpointer user_data)
      */
     if (!(dependent_fd->dependent_of_displayed || dependent_fd->passed_dfilter)) {
       dependent_fd->dependent_of_displayed = 1;
-      g_slist_foreach(dependent_fd->dependent_frames, find_and_mark_frame_depended_upon, frames);
+      if (dependent_fd->dependent_frames) {
+        g_hash_table_foreach(dependent_fd->dependent_frames, find_and_mark_frame_depended_upon, frames);
+      }
     }
   }
 }

epan/frame_data_sequence.h

@@ -33,7 +33,7 @@ WS_DLL_PUBLIC frame_data *frame_data_sequence_find(frame_data_sequence *fds,
  */
 WS_DLL_PUBLIC void free_frame_data_sequence(frame_data_sequence *fds);
 
-WS_DLL_PUBLIC void find_and_mark_frame_depended_upon(gpointer data, gpointer user_data);
+WS_DLL_PUBLIC void find_and_mark_frame_depended_upon(gpointer key, gpointer value, gpointer user_data);
 
 
 #ifdef __cplusplus

epan/packet.c

@@ -452,13 +452,10 @@ mark_frame_as_depended_upon(frame_data *fd, guint32 frame_num)
 		/* ws_assert(frame_num < fd->num) - we assume in several other
 		 * places in the code that frames don't depend on future
 		 * frames. */
-		/* XXX: Looking to see if the frame is already there is slow
-		 * if there's a lot of dependent frames, so this should
-		 * be a hash table or something.
-		 */
-		if (g_slist_find(fd->dependent_frames, GUINT_TO_POINTER(frame_num)) == NULL) {
-			fd->dependent_frames = g_slist_prepend(fd->dependent_frames, GUINT_TO_POINTER(frame_num));
+		if (fd->dependent_frames == NULL) {
+			fd->dependent_frames = g_hash_table_new(g_direct_hash, g_direct_equal);
 		}
+		g_hash_table_insert(fd->dependent_frames, GUINT_TO_POINTER(frame_num), NULL);
 	}
 }
 

file.c

@@ -1194,12 +1194,12 @@ add_packet_to_packet_list(frame_data *fdata, capture_file *cf,
     if (dfcode != NULL) {
         fdata->passed_dfilter = dfilter_apply_edt(dfcode, edt) ? 1 : 0;
 
-        if (fdata->passed_dfilter) {
+        if (fdata->passed_dfilter && edt->pi.fd->dependent_frames) {
             /* This frame passed the display filter but it may depend on other
              * (potentially not displayed) frames.  Find those frames and mark them
              * as depended upon.
              */
-            g_slist_foreach(edt->pi.fd->dependent_frames, find_and_mark_frame_depended_upon, cf->provider.frames);
+            g_hash_table_foreach(edt->pi.fd->dependent_frames, find_and_mark_frame_depended_upon, cf->provider.frames);
         }
     } else
         fdata->passed_dfilter = 1;

packaging/debian/libwireshark0.symbols

@@ -678,7 +678,7 @@ libwireshark.so.0 libwireshark0 #MINVER#
  fetch_tapped_data@Base 1.9.1
  filter_expression_iterate_expressions@Base 2.5.0
  filter_expression_new@Base 1.9.1
- find_and_mark_frame_depended_upon@Base 1.12.0~rc1
+ find_and_mark_frame_depended_upon@Base 4.1.0
  find_capture_dissector@Base 2.3.0
  find_conversation@Base 1.9.1
  find_conversation_by_id@Base 2.5.0

sharkd.c

@@ -315,8 +315,8 @@ process_packet(capture_file *cf, epan_dissect_t *edt,
          * if a display filter was given and it matches this packet.
          */
         if (edt && cf->dfcode) {
-            if (dfilter_apply_edt(cf->dfcode, edt)) {
-                g_slist_foreach(edt->pi.fd->dependent_frames, find_and_mark_frame_depended_upon, cf->provider.frames);
+            if (dfilter_apply_edt(cf->dfcode, edt) && edt->pi.fd->dependent_frames) {
+                g_hash_table_foreach(edt->pi.fd->dependent_frames, find_and_mark_frame_depended_upon, cf->provider.frames);
             }
         }
 

tfshark.c

@@ -1071,8 +1071,8 @@ process_packet_first_pass(capture_file *cf, epan_dissect_t *edt,
          * More importantly, edt.pi.fd.dependent_frames won't be initialized because
          * epan hasn't been initialized.
          */
-        if (edt) {
-            g_slist_foreach(edt->pi.fd->dependent_frames, find_and_mark_frame_depended_upon, cf->provider.frames);
+        if (edt && edt->pi.fd->dependent_frames) {
+            g_hash_table_foreach(edt->pi.fd->dependent_frames, find_and_mark_frame_depended_upon, cf->provider.frames);
         }
 
         cf->count++;

tshark.c

@@ -3056,8 +3056,8 @@ process_packet_first_pass(capture_file *cf, epan_dissect_t *edt,
          * if a display filter was given and it matches this packet.
          */
         if (edt && cf->dfcode) {
-            if (dfilter_apply_edt(cf->dfcode, edt)) {
-                g_slist_foreach(edt->pi.fd->dependent_frames, find_and_mark_frame_depended_upon, cf->provider.frames);
+            if (dfilter_apply_edt(cf->dfcode, edt) && edt->pi.fd->dependent_frames) {
+                g_hash_table_foreach(edt->pi.fd->dependent_frames, find_and_mark_frame_depended_upon, cf->provider.frames);
             }
 
             if (selected_frame_number != 0 && selected_frame_number == cf->count + 1) {