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Change-Id: I9ea2160b550243b45f6798ad3339f6a45b34a4ef Reviewed-on: https://code.wireshark.org/review/3991 Reviewed-by: Evan Huus <eapache@gmail.com>
314 lines
8.6 KiB
C
314 lines
8.6 KiB
C
/* tvbuff_composite.c
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*
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* Copyright (c) 2000 by Gilbert Ramirez <gram@alumni.rice.edu>
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <epan/emem.h>
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#include "tvbuff.h"
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#include "tvbuff-int.h"
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#include "proto.h" /* XXX - only used for DISSECTOR_ASSERT, probably a new header file? */
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typedef struct {
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GSList *tvbs;
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/* Used for quick testing to see if this
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* is the tvbuff that a COMPOSITE is
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* interested in. */
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guint *start_offsets;
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guint *end_offsets;
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} tvb_comp_t;
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struct tvb_composite {
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struct tvbuff tvb;
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tvb_comp_t composite;
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};
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static void
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composite_free(tvbuff_t *tvb)
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{
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struct tvb_composite *composite_tvb = (struct tvb_composite *) tvb;
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tvb_comp_t *composite = &composite_tvb->composite;
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g_slist_free(composite->tvbs);
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g_free(composite->start_offsets);
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g_free(composite->end_offsets);
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if (tvb->real_data) {
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/*
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* XXX - do this with a union?
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*/
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g_free((gpointer)tvb->real_data);
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}
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}
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static guint
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composite_offset(const tvbuff_t *tvb, const guint counter)
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{
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const struct tvb_composite *composite_tvb = (const struct tvb_composite *) tvb;
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const tvbuff_t *member = (const tvbuff_t *)composite_tvb->composite.tvbs->data;
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return tvb_offset_from_real_beginning_counter(member, counter);
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}
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static const guint8*
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composite_get_ptr(tvbuff_t *tvb, guint abs_offset, guint abs_length)
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{
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struct tvb_composite *composite_tvb = (struct tvb_composite *) tvb;
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guint i, num_members;
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tvb_comp_t *composite;
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tvbuff_t *member_tvb = NULL;
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guint member_offset;
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GSList *slist;
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/* DISSECTOR_ASSERT(tvb->ops == &tvb_composite_ops); */
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/* Maybe the range specified by offset/length
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* is contiguous inside one of the member tvbuffs */
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composite = &composite_tvb->composite;
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num_members = g_slist_length(composite->tvbs);
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for (i = 0; i < num_members; i++) {
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if (abs_offset <= composite->end_offsets[i]) {
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slist = g_slist_nth(composite->tvbs, i);
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member_tvb = (tvbuff_t *)slist->data;
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break;
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}
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}
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/* special case */
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if (!member_tvb) {
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DISSECTOR_ASSERT(abs_offset == tvb->length && abs_length == 0);
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return "";
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}
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member_offset = abs_offset - composite->start_offsets[i];
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if (tvb_bytes_exist(member_tvb, member_offset, abs_length)) {
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/*
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* The range is, in fact, contiguous within member_tvb.
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*/
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DISSECTOR_ASSERT(!tvb->real_data);
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return tvb_get_ptr(member_tvb, member_offset, abs_length);
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}
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else {
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tvb->real_data = (guint8 *)tvb_memdup(NULL, tvb, 0, -1);
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return tvb->real_data + abs_offset;
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}
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DISSECTOR_ASSERT_NOT_REACHED();
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}
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static void *
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composite_memcpy(tvbuff_t *tvb, void* _target, guint abs_offset, guint abs_length)
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{
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struct tvb_composite *composite_tvb = (struct tvb_composite *) tvb;
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guint8 *target = (guint8 *) _target;
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guint i, num_members;
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tvb_comp_t *composite;
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tvbuff_t *member_tvb = NULL;
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guint member_offset, member_length;
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GSList *slist;
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/* DISSECTOR_ASSERT(tvb->ops == &tvb_composite_ops); */
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/* Maybe the range specified by offset/length
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* is contiguous inside one of the member tvbuffs */
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composite = &composite_tvb->composite;
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num_members = g_slist_length(composite->tvbs);
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for (i = 0; i < num_members; i++) {
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if (abs_offset <= composite->end_offsets[i]) {
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slist = g_slist_nth(composite->tvbs, i);
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member_tvb = (tvbuff_t *)slist->data;
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break;
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}
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}
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/* special case */
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if (!member_tvb) {
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DISSECTOR_ASSERT(abs_offset == tvb->length && abs_length == 0);
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return target;
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}
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member_offset = abs_offset - composite->start_offsets[i];
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if (tvb_bytes_exist(member_tvb, member_offset, abs_length)) {
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DISSECTOR_ASSERT(!tvb->real_data);
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return tvb_memcpy(member_tvb, target, member_offset, abs_length);
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}
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else {
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/* The requested data is non-contiguous inside
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* the member tvb. We have to memcpy() the part that's in the member tvb,
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* then iterate across the other member tvb's, copying their portions
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* until we have copied all data.
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*/
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member_length = tvb_length_remaining(member_tvb, member_offset);
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/* composite_memcpy() can't handle a member_length of zero. */
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DISSECTOR_ASSERT(member_length > 0);
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tvb_memcpy(member_tvb, target, member_offset, member_length);
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abs_offset += member_length;
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abs_length -= member_length;
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/* Recurse */
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if (abs_length > 0) {
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composite_memcpy(tvb, target + member_length, abs_offset, abs_length);
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}
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return target;
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}
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DISSECTOR_ASSERT_NOT_REACHED();
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}
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static const struct tvb_ops tvb_composite_ops = {
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sizeof(struct tvb_composite), /* size */
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composite_free, /* free */
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composite_offset, /* offset */
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composite_get_ptr, /* get_ptr */
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composite_memcpy, /* memcpy */
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NULL, /* find_guint8 XXX */
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NULL, /* pbrk_guint8 XXX */
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NULL, /* clone */
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};
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/*
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* Composite tvb
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*
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* 1. A composite tvb is automatically chained to its first member when the
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* tvb is finalized.
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* This means that composite tvb members must all be in the same chain.
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* ToDo: enforce this: By searching the chain?
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*/
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tvbuff_t *
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tvb_new_composite(void)
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{
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tvbuff_t *tvb = tvb_new(&tvb_composite_ops);
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struct tvb_composite *composite_tvb = (struct tvb_composite *) tvb;
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tvb_comp_t *composite = &composite_tvb->composite;
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composite->tvbs = NULL;
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composite->start_offsets = NULL;
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composite->end_offsets = NULL;
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return tvb;
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}
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void
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tvb_composite_append(tvbuff_t *tvb, tvbuff_t *member)
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{
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struct tvb_composite *composite_tvb = (struct tvb_composite *) tvb;
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tvb_comp_t *composite;
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DISSECTOR_ASSERT(tvb && !tvb->initialized);
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DISSECTOR_ASSERT(tvb->ops == &tvb_composite_ops);
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/* Don't allow zero-length TVBs: composite_memcpy() can't handle them
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* and anyway it makes no sense.
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*/
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DISSECTOR_ASSERT(member->length);
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composite = &composite_tvb->composite;
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composite->tvbs = g_slist_append(composite->tvbs, member);
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}
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void
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tvb_composite_prepend(tvbuff_t *tvb, tvbuff_t *member)
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{
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struct tvb_composite *composite_tvb = (struct tvb_composite *) tvb;
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tvb_comp_t *composite;
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DISSECTOR_ASSERT(tvb && !tvb->initialized);
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DISSECTOR_ASSERT(tvb->ops == &tvb_composite_ops);
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/* Don't allow zero-length TVBs: composite_memcpy() can't handle them
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* and anyway it makes no sense.
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*/
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DISSECTOR_ASSERT(member->length);
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composite = &composite_tvb->composite;
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composite->tvbs = g_slist_prepend(composite->tvbs, member);
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}
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void
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tvb_composite_finalize(tvbuff_t *tvb)
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{
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struct tvb_composite *composite_tvb = (struct tvb_composite *) tvb;
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GSList *slist;
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guint num_members;
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tvbuff_t *member_tvb;
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tvb_comp_t *composite;
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int i = 0;
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DISSECTOR_ASSERT(tvb && !tvb->initialized);
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DISSECTOR_ASSERT(tvb->ops == &tvb_composite_ops);
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DISSECTOR_ASSERT(tvb->length == 0);
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DISSECTOR_ASSERT(tvb->reported_length == 0);
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composite = &composite_tvb->composite;
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num_members = g_slist_length(composite->tvbs);
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/* Dissectors should not create composite TVBs if they're not going to
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* put at least one TVB in them.
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* (Without this check--or something similar--we'll seg-fault below.)
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*/
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DISSECTOR_ASSERT(num_members);
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composite->start_offsets = g_new(guint, num_members);
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composite->end_offsets = g_new(guint, num_members);
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for (slist = composite->tvbs; slist != NULL; slist = slist->next) {
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DISSECTOR_ASSERT((guint) i < num_members);
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member_tvb = (tvbuff_t *)slist->data;
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composite->start_offsets[i] = tvb->length;
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tvb->length += member_tvb->length;
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tvb->reported_length += member_tvb->reported_length;
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composite->end_offsets[i] = tvb->length - 1;
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i++;
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}
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DISSECTOR_ASSERT(composite->tvbs);
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tvb_add_to_chain((tvbuff_t *)composite->tvbs->data, tvb); /* chain composite tvb to first member */
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tvb->initialized = TRUE;
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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