forked from osmocom/wireshark
![Guy Harris](/assets/img/avatar_default.png)
* gcc 3.0 warning fixes: - text2pcap.c: The number of characters to scan should probably not be 0 - wiretap/csids.c: using preincrement on a variable used on both sides of an assignment might be undefined by the C99(?) standard * turn on additional warnings for epan and wiretap too - epan/configure.in - wiretap/configure.in * Fix some warnings (missing includes, signed/unsigned, missing initializers) found by turning on the warnings - all other files :-) svn path=/trunk/; revision=3709
385 lines
8.2 KiB
C
385 lines
8.2 KiB
C
/*
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* $Id: dfilter.c,v 1.5 2001/07/13 00:55:54 guy Exp $
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@zing.org>
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* Copyright 2001 Gerald Combs
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*
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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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <stdio.h>
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#include <string.h>
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#ifdef NEED_SNPRINTF_H
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#include "snprintf.h"
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#endif
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#include "dfilter-int.h"
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#include "syntax-tree.h"
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#include "gencode.h"
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#include "semcheck.h"
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#include "dfvm.h"
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/* Balanced tree of abbreviations and IDs */
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GTree *dfilter_tokens = NULL;
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#define DFILTER_TOKEN_ID_OFFSET 1
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/* Comparision function for tree insertion. A wrapper around strcmp() */
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static int g_strcmp(gconstpointer a, gconstpointer b);
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/* Global error message space for dfilter_compile errors */
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gchar dfilter_error_msg_buf[1024];
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gchar *dfilter_error_msg; /* NULL when no error resulted */
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/* In proto.c */
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extern int hf_text_only;
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/* From scanner.c */
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void df_scanner_text(const char *text);
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void df_scanner_file(FILE *fh);
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void df_scanner_cleanup(void);
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int df_lex(void);
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/* Holds the singular instance of our Lemon parser object */
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void* ParserObj = NULL;
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void
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dfilter_fail(char *format, ...)
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{
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va_list args;
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/* If we've already reported one error, don't overwite it */
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if (dfilter_error_msg != NULL)
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return;
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va_start(args, format);
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vsnprintf(dfilter_error_msg_buf, sizeof(dfilter_error_msg_buf),
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format, args);
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dfilter_error_msg = dfilter_error_msg_buf;
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va_end(args);
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}
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/* Initialize the dfilter module */
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void
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dfilter_init(void)
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{
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int id, num_symbols;
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char *abbrev;
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header_field_info *hfinfo, *same_name_hfinfo, *same_name_next_hfinfo;
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num_symbols = proto_registrar_n();
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if (dfilter_tokens) {
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/* XXX - needed? */
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g_message("I expected hf_ids to be NULL\n");
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g_tree_destroy(dfilter_tokens);
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/* Make sure the hfinfo->same_name links are broken */
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for (id = 0; id < num_symbols; id++) {
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hfinfo = proto_registrar_get_nth(id);
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hfinfo->same_name_next = NULL;
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hfinfo->same_name_prev = NULL;
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}
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}
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dfilter_tokens = g_tree_new(g_strcmp);
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/* Populate the abbrev/ID GTree (header-field symbol table) */
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for (id = 0; id < num_symbols; id++) {
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if (id == hf_text_only) {
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continue;
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}
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abbrev = proto_registrar_get_abbrev(id);
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hfinfo = proto_registrar_get_nth(id);
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g_assert(abbrev); /* Not Null */
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g_assert(abbrev[0] != 0); /* Not empty string */
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/* We allow multiple hfinfo's to be registered under the same
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* abbreviation. This was done for X.25, as, depending
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* on whether it's modulo-8 or modulo-128 operation,
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* some bitfield fields may be in different bits of
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* a byte, and we want to be able to refer to that field
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* with one name regardless of whether the packets
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* are modulo-8 or modulo-128 packets. */
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same_name_hfinfo = g_tree_lookup(dfilter_tokens, abbrev);
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if (same_name_hfinfo) {
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/* There's already a field with this name.
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* Put it after that field in the list of
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* fields with this name, then allow the code
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* after this if{} block to replace the old
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* hfinfo with the new hfinfo in the GTree. Thus,
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* we end up with a linked-list of same-named hfinfo's,
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* with the root of the list being the hfinfo in the GTree */
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same_name_next_hfinfo =
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same_name_hfinfo->same_name_next;
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hfinfo->same_name_next = same_name_next_hfinfo;
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if (same_name_next_hfinfo)
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same_name_next_hfinfo->same_name_prev = hfinfo;
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same_name_hfinfo->same_name_next = hfinfo;
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hfinfo->same_name_prev = same_name_hfinfo;
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}
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g_tree_insert(dfilter_tokens, abbrev, hfinfo);
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}
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if (ParserObj) {
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g_message("I expected ParserObj to be NULL\n");
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/* Free the Lemon Parser object */
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DfilterFree(ParserObj, g_free);
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}
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/* Allocate an instance of our Lemon-based parser */
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ParserObj = DfilterAlloc(g_malloc);
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/* Initialize the syntax-tree sub-sub-system */
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sttype_init();
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}
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/* Clean-up the dfilter module */
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void
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dfilter_cleanup(void)
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{
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/* Free the abbrev/ID GTree */
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if (dfilter_tokens) {
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g_tree_destroy(dfilter_tokens);
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dfilter_tokens = NULL;
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}
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/* Free the Lemon Parser object */
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if (ParserObj) {
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DfilterFree(ParserObj, g_free);
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}
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/* Clean up the syntax-tree sub-sub-system */
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sttype_cleanup();
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}
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/* Lookup an abbreviation in our token tree, returing the ID #
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* If the abbreviation doesn't exit, returns -1 */
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header_field_info*
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dfilter_lookup_token(char *abbrev)
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{
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g_assert(abbrev != NULL);
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return g_tree_lookup(dfilter_tokens, abbrev);
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}
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/* String comparison func for dfilter_token GTree */
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static int
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g_strcmp(gconstpointer a, gconstpointer b)
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{
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return strcmp((const char*)a, (const char*)b);
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}
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static dfilter_t*
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dfilter_new(void)
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{
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dfilter_t *df;
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df = g_new(dfilter_t, 1);
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df->insns = NULL;
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return df;
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}
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/* Given a GPtrArray of instructions (dfvm_insn_t),
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* free them. */
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static void
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free_insns(GPtrArray *insns)
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{
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unsigned int i;
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dfvm_insn_t *insn;
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for (i = 0; i < insns->len; i++) {
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insn = g_ptr_array_index(insns, i);
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dfvm_insn_free(insn);
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}
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}
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void
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dfilter_free(dfilter_t *df)
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{
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if (df->insns) {
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free_insns(df->insns);
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}
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g_free(df->registers);
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g_free(df->attempted_load);
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g_free(df);
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}
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static dfwork_t*
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dfwork_new(void)
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{
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dfwork_t *dfw;
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dfw = g_new(dfwork_t, 1);
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dfw->st_root = NULL;
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dfw->syntax_error = FALSE;
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dfw->insns = NULL;
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dfw->loaded_fields = NULL;
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dfw->next_insn_id = 0;
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dfw->next_register = 0;
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return dfw;
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}
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static void
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dfwork_free(dfwork_t *dfw)
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{
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if (dfw->st_root) {
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stnode_free(dfw->st_root);
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}
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if (dfw->loaded_fields) {
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g_hash_table_destroy(dfw->loaded_fields);
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}
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if (dfw->insns) {
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free_insns(dfw->insns);
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}
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g_free(dfw);
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}
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gboolean
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dfilter_compile(gchar *text, dfilter_t **dfp)
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{
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int token;
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dfilter_t *dfilter;
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dfwork_t *dfw;
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dfilter_error_msg = NULL;
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dfw = dfwork_new();
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df_scanner_text(text);
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while (1) {
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df_lval = stnode_new(STTYPE_UNINITIALIZED, NULL);
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token = df_lex();
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/* Check for end-of-input */
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if (token == 0) {
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/* Tell the parser that we have reached the end of input */
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Dfilter(ParserObj, 0, NULL, dfw);
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/* Free the stnode_t that we just generated, since
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* the parser doesn't know about it and won't free it
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* for us. */
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stnode_free(df_lval);
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df_lval = NULL;
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break;
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}
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/* Give the token to the parser */
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Dfilter(ParserObj, token, df_lval, dfw);
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if (dfw->syntax_error) {
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break;
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}
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}
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/* One last check for syntax error (after EOF) */
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if (dfw->syntax_error) {
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goto FAILURE;
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}
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/* Success, but was it an empty filter? If so, discard
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* it and set *dfp to NULL */
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if (dfw->st_root == NULL) {
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*dfp = NULL;
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}
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else {
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/* Check semantics and do necessary type conversion*/
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if (!dfw_semcheck(dfw)) {
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goto FAILURE;
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}
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/* Create bytecode */
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dfw_gencode(dfw);
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/* Tuck away the bytecode in the dfilter_t */
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dfilter = dfilter_new();
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dfilter->insns = dfw->insns;
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dfw->insns = NULL;
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/* Initialize run-time space */
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dfilter->num_registers = dfw->next_register;
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dfilter->registers = g_new0(GList*, dfilter->num_registers);
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dfilter->attempted_load = g_new0(gboolean, dfilter->num_registers);
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/* And give it to the user. */
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*dfp = dfilter;
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}
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/* SUCCESS */
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dfwork_free(dfw);
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/* Reset flex */
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df_scanner_cleanup();
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return TRUE;
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FAILURE:
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if (dfw) {
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dfwork_free(dfw);
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}
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dfilter_fail("Unable to parse filter string \"%s\".", text);
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*dfp = NULL;
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/* Reset flex */
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df_scanner_cleanup();
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return FALSE;
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}
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gboolean
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dfilter_apply(dfilter_t *df, tvbuff_t *tvb, proto_tree *tree)
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{
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return dfvm_apply(df, tvb, tree);
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}
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gboolean
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dfilter_apply_edt(dfilter_t *df, epan_dissect_t* edt)
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{
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return dfvm_apply(df, edt->tvb, edt->tree);
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}
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void
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dfilter_dump(dfilter_t *df)
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{
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dfvm_dump(stdout, df->insns);
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}
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