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wireshark/epan/frame_data_sequence.c
Guy Harris b7e9582fd7 Fix the calculation of the number of levels in the radix tree. 
The algorithm being used calculated the number of levels in a
1024-leaf-node tree as being 2, but it's 1 - 0 elements means 0 levels,
1 through 1024 elements means 1 level, 1025 through 1024^2 elements
means 2 levels, etc..  With a count of 1024, the loop would bump the
level count from 0 to 1, and divide the element count by 1024, yielding
1, so the loop would not terminate, and the level count would them go
from 1 to 2 and the element count would go to 0.

This could cause problems if exactly 1024 packets were seen.

Just use an if chain, similar to the one used when adding elements to
the tree.

Bug: 13433
Change-Id: I3eaeaf374bb65b37b38a59e95f77cac6690614ed
Reviewed-on: https://code.wireshark.org/review/20379
Reviewed-by: Guy Harris <guy@alum.mit.edu>
2017-03-04 04:35:42 +00:00

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/* frame_data_sequence.c
* Implements a sequence of frame_data structures
*
* 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.
*/
#include "config.h"
#include <glib.h>
#include <epan/packet.h>
#include "frame_data_sequence.h"
/*
* We store the frame_data structures in a radix tree, with 1024
* elements per level. The leaf nodes are arrays of 1024 frame_data
* structures; the nodes above them are arrays of 1024 pointers to
* the nodes below them. The capture_file structure has a pointer
* to the root node.
*
* As frame numbers are 32 bits, and as 1024 is 2^10, that gives us
* up to 4 levels of tree.
*/
#define LOG2_NODES_PER_LEVEL 10
#define NODES_PER_LEVEL (1<<LOG2_NODES_PER_LEVEL)
struct _frame_data_sequence {
guint32 count; /* Total number of frames */
void *ptree_root; /* Pointer to the root node */
};
/*
* For a given frame number, calculate the indices into a level 3
* node, a level 2 node, a level 1 node, and a leaf node.
*/
#define LEVEL_3_INDEX(framenum) \
((framenum) >> (3*LOG2_NODES_PER_LEVEL))
#define LEVEL_2_INDEX(framenum) \
(((framenum) >> (2*LOG2_NODES_PER_LEVEL)) & (NODES_PER_LEVEL - 1))
#define LEVEL_1_INDEX(framenum) \
(((framenum) >> (1*LOG2_NODES_PER_LEVEL)) & (NODES_PER_LEVEL - 1))
#define LEAF_INDEX(framenum) \
(((framenum) >> (0*LOG2_NODES_PER_LEVEL)) & (NODES_PER_LEVEL - 1))
frame_data_sequence *
new_frame_data_sequence(void)
{
frame_data_sequence *fds;
fds = (frame_data_sequence *)g_malloc(sizeof *fds);
fds->count = 0;
fds->ptree_root = NULL;
return fds;
}
/*
* Add a new frame_data structure to a frame_data_sequence.
*/
frame_data *
frame_data_sequence_add(frame_data_sequence *fds, frame_data *fdata)
{
frame_data *leaf;
frame_data **level1;
frame_data ***level2;
frame_data ****level3;
frame_data *node;
/*
* The current value of fds->count is the index value for the new frame,
* because the index value for a frame is the frame number - 1, and
* if we currently have fds->count frames, the the frame number of
* the last frame in the collection is fds->count, so its index value
* is fds->count - 1.
*/
if (fds->count == 0) {
/* The tree is empty; allocate the first leaf node, which will be
the root node. */
leaf = (frame_data *)g_malloc((sizeof *leaf)*NODES_PER_LEVEL);
node = &leaf[0];
fds->ptree_root = leaf;
} else if (fds->count < NODES_PER_LEVEL) {
/* It's a 1-level tree, and is going to stay that way for now. */
leaf = (frame_data *)fds->ptree_root;
node = &leaf[fds->count];
} else if (fds->count == NODES_PER_LEVEL) {
/* It's a 1-level tree that will turn into a 2-level tree. */
level1 = (frame_data **)g_malloc0((sizeof *level1)*NODES_PER_LEVEL);
level1[0] = (frame_data *)fds->ptree_root;
leaf = (frame_data *)g_malloc((sizeof *leaf)*NODES_PER_LEVEL);
level1[1] = leaf;
node = &leaf[0];
fds->ptree_root = level1;
} else if (fds->count < NODES_PER_LEVEL*NODES_PER_LEVEL) {
/* It's a 2-level tree, and is going to stay that way for now. */
level1 = (frame_data **)fds->ptree_root;
leaf = level1[fds->count >> LOG2_NODES_PER_LEVEL];
if (leaf == NULL) {
leaf = (frame_data *)g_malloc((sizeof *leaf)*NODES_PER_LEVEL);
level1[fds->count >> LOG2_NODES_PER_LEVEL] = leaf;
}
node = &leaf[LEAF_INDEX(fds->count)];
} else if (fds->count == NODES_PER_LEVEL*NODES_PER_LEVEL) {
/* It's a 2-level tree that will turn into a 3-level tree */
level2 = (frame_data ***)g_malloc0((sizeof *level2)*NODES_PER_LEVEL);
level2[0] = (frame_data **)fds->ptree_root;
level1 = (frame_data **)g_malloc0((sizeof *level1)*NODES_PER_LEVEL);
level2[1] = level1;
leaf = (frame_data *)g_malloc((sizeof *leaf)*NODES_PER_LEVEL);
level1[0] = leaf;
node = &leaf[0];
fds->ptree_root = level2;
} else if (fds->count < NODES_PER_LEVEL*NODES_PER_LEVEL*NODES_PER_LEVEL) {
/* It's a 3-level tree, and is going to stay that way for now. */
level2 = (frame_data ***)fds->ptree_root;
level1 = level2[fds->count >> (LOG2_NODES_PER_LEVEL+LOG2_NODES_PER_LEVEL)];
if (level1 == NULL) {
level1 = (frame_data **)g_malloc0((sizeof *level1)*NODES_PER_LEVEL);
level2[fds->count >> (LOG2_NODES_PER_LEVEL+LOG2_NODES_PER_LEVEL)] = level1;
}
leaf = level1[LEVEL_1_INDEX(fds->count)];
if (leaf == NULL) {
leaf = (frame_data *)g_malloc((sizeof *leaf)*NODES_PER_LEVEL);
level1[LEVEL_1_INDEX(fds->count)] = leaf;
}
node = &leaf[LEAF_INDEX(fds->count)];
} else if (fds->count == NODES_PER_LEVEL*NODES_PER_LEVEL*NODES_PER_LEVEL) {
/* It's a 3-level tree that will turn into a 4-level tree */
level3 = (frame_data ****)g_malloc0((sizeof *level3)*NODES_PER_LEVEL);
level3[0] = (frame_data ***)fds->ptree_root;
level2 = (frame_data ***)g_malloc0((sizeof *level2)*NODES_PER_LEVEL);
level3[1] = level2;
level1 = (frame_data **)g_malloc0((sizeof *level1)*NODES_PER_LEVEL);
level2[0] = level1;
leaf = (frame_data *)g_malloc((sizeof *leaf)*NODES_PER_LEVEL);
level1[0] = leaf;
node = &leaf[0];
fds->ptree_root = level3;
} else {
/* fds->count is 2^32-1 at most, and NODES_PER_LEVEL^4
2^(LOG2_NODES_PER_LEVEL*4), and LOG2_NODES_PER_LEVEL is 10,
so fds->count is always less < NODES_PER_LEVEL^4.
XXX - we should fail if fds->count is 2^31-1, or should
make the frame numbers 64-bit and just let users run
themselves out of address space or swap space. :-) */
/* It's a 4-level tree, and is going to stay that way forever. */
level3 = (frame_data ****)fds->ptree_root;
level2 = level3[LEVEL_3_INDEX(fds->count)];
if (level2 == NULL) {
level2 = (frame_data ***)g_malloc0((sizeof *level2)*NODES_PER_LEVEL);
level3[LEVEL_3_INDEX(fds->count)] = level2;
}
level1 = level2[LEVEL_2_INDEX(fds->count)];
if (level1 == NULL) {
level1 = (frame_data **)g_malloc0((sizeof *level1)*NODES_PER_LEVEL);
level2[LEVEL_2_INDEX(fds->count)] = level1;
}
leaf = level1[LEVEL_1_INDEX(fds->count)];
if (leaf == NULL) {
leaf = (frame_data *)g_malloc((sizeof *leaf)*NODES_PER_LEVEL);
level1[LEVEL_1_INDEX(fds->count)] = leaf;
}
node = &leaf[LEAF_INDEX(fds->count)];
}
*node = *fdata;
fds->count++;
return node;
}
/*
* Find the frame_data for the specified frame number.
*/
frame_data *
frame_data_sequence_find(frame_data_sequence *fds, guint32 num)
{
frame_data *leaf;
frame_data **level1;
frame_data ***level2;
frame_data ****level3;
if (num == 0) {
/* There is no frame number 0 */
return NULL;
}
/* Convert it into an index number. */
num--;
if (num >= fds->count) {
/* There aren't that many frames. */
return NULL;
}
if (fds->count <= NODES_PER_LEVEL) {
/* It's a 1-level tree. */
leaf = (frame_data *)fds->ptree_root;
return &leaf[num];
}
if (fds->count <= NODES_PER_LEVEL*NODES_PER_LEVEL) {
/* It's a 2-level tree. */
level1 = (frame_data **)fds->ptree_root;
leaf = level1[num >> LOG2_NODES_PER_LEVEL];
return &leaf[LEAF_INDEX(num)];
}
if (fds->count <= NODES_PER_LEVEL*NODES_PER_LEVEL*NODES_PER_LEVEL) {
/* It's a 3-level tree. */
level2 = (frame_data ***)fds->ptree_root;
level1 = level2[num >> (LOG2_NODES_PER_LEVEL+LOG2_NODES_PER_LEVEL)];
leaf = level1[(num >> LOG2_NODES_PER_LEVEL) & (NODES_PER_LEVEL - 1)];
return &leaf[LEAF_INDEX(num)];
}
/* fds->count is 2^32-1 at most, and NODES_PER_LEVEL^4
2^(LOG2_NODES_PER_LEVEL*4), and LOG2_NODES_PER_LEVEL is 10,
so fds->count is always less < NODES_PER_LEVEL^4. */
/* It's a 4-level tree, and is going to stay that way forever. */
level3 = (frame_data ****)fds->ptree_root;
level2 = level3[num >> (LOG2_NODES_PER_LEVEL+LOG2_NODES_PER_LEVEL+LOG2_NODES_PER_LEVEL)];
level1 = level2[(num >> (LOG2_NODES_PER_LEVEL+LOG2_NODES_PER_LEVEL)) & (NODES_PER_LEVEL - 1)];
leaf = level1[(num >> LOG2_NODES_PER_LEVEL) & (NODES_PER_LEVEL - 1)];
return &leaf[LEAF_INDEX(num)];
}
/* recursively frees a frame_data radix level */
static void
free_frame_data_array(void *array, guint count, guint level, gboolean last)
{
guint i, level_count;
if (last) {
/* if we are the last in our given parent's row, we may not have
* exactly a full row, so do the bit twiddling to figure out exactly
* how many fields we have */
level_count = (count >> ((level - 1) * LOG2_NODES_PER_LEVEL)) &
(NODES_PER_LEVEL - 1);
/* the above calculation rounds down, so make sure we count correctly
* if count is not an even multiple of NODES_PER_LEVEL */
if (count & ((1 << ((level - 1) * LOG2_NODES_PER_LEVEL)) - 1)) {
level_count++;
}
}
else {
/* if we're not the last in our parent, then we're guaranteed to have
* a full array */
level_count = NODES_PER_LEVEL;
}
if (level > 1) {
/* recurse on every sub-array, passing on our own 'last' value
* specially to our last child */
frame_data **real_array = (frame_data **) array;
for (i=0; i < level_count-1; i++) {
free_frame_data_array(real_array[i], count, level-1, FALSE);
}
free_frame_data_array(real_array[level_count-1], count, level-1, last);
}
else if (level == 1) {
/* bottom level, so just clean up all the frame data */
frame_data *real_array = (frame_data *) array;
for (i=0; i < level_count; i++) {
frame_data_destroy(&real_array[i]);
}
}
/* free the array itself */
g_free(array);
}
/*
* Free a frame_data_sequence and all the frame_data structures in it.
*/
void
free_frame_data_sequence(frame_data_sequence *fds)
{
guint levels;
/* calculate how many levels we have */
if (fds->count == 0) {
/* The tree is empty; there are no levels. */
levels = 0;
} else if (fds->count <= NODES_PER_LEVEL) {
/* It's a 1-level tree. */
levels = 1;
} else if (fds->count <= NODES_PER_LEVEL*NODES_PER_LEVEL) {
/* It's a 2-level tree. */
levels = 2;
} else if (fds->count <= NODES_PER_LEVEL*NODES_PER_LEVEL*NODES_PER_LEVEL) {
/* It's a 3-level tree. */
levels = 3;
} else {
/* fds->count is 2^32-1 at most, and NODES_PER_LEVEL^4
2^(LOG2_NODES_PER_LEVEL*4), and LOG2_NODES_PER_LEVEL is 10,
so fds->count is always less < NODES_PER_LEVEL^4. */
/* It's a 4-level tree. */
levels = 4;
}
/* call the recursive free function */
if (levels > 0) {
free_frame_data_array(fds->ptree_root, fds->count, levels, TRUE);
}
/* free the header struct */
g_free(fds);
}
void
find_and_mark_frame_depended_upon(gpointer data, gpointer user_data)
{
frame_data *dependent_fd;
guint32 dependent_frame = GPOINTER_TO_UINT(data);
frame_data_sequence *frames = (frame_data_sequence *)user_data;
if (dependent_frame && frames) {
dependent_fd = frame_data_sequence_find(frames, dependent_frame);
dependent_fd->flags.dependent_of_displayed = 1;
}
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 2
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=2 tabstop=8 expandtab:
* :indentSize=2:tabSize=8:noTabs=true:
*/
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