185 lines
5.1 KiB
C
185 lines
5.1 KiB
C
/*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 2001 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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/* Perl-Compatible Regular Expression (PCRE) internal field type.
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* Used with the "matches" dfilter operator, allowing efficient
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* compilation and studying of a PCRE pattern in dfilters.
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*/
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#include "config.h"
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#include <ftypes-int.h>
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#include <glib.h>
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#include <string.h>
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static void
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gregex_fvalue_new(fvalue_t *fv)
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{
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fv->value.re = NULL;
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}
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static void
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gregex_fvalue_free(fvalue_t *fv)
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{
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if (fv->value.re) {
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g_regex_unref(fv->value.re);
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fv->value.re = NULL;
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}
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}
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/* Determines whether pattern needs to match raw byte sequences */
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static gboolean
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raw_flag_needed(const gchar *pattern)
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{
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gboolean found = FALSE;
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const gchar *s = pattern;
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size_t i, len;
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/* find any character whose hex value is two letters */
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len = strlen(s);
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for (i = 0; i < len; i++) {
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/* Upper and lower-nibble must be >= 0xA */
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if ((guchar)(s[i] & 0xF0) >= 0xA0 &&
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(guchar)(s[i] & 0x0F) >= 0x0A)
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{
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found = TRUE;
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break;
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}
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}
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return found;
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}
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/* Generate a FT_PCRE from a parsed string pattern.
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* On failure, if err_msg is non-null, set *err_msg to point to a
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* g_malloc()ed error message. */
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static gboolean
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val_from_string(fvalue_t *fv, const char *pattern, gchar **err_msg)
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{
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GError *regex_error = NULL;
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GRegexCompileFlags cflags = (GRegexCompileFlags)(G_REGEX_CASELESS | G_REGEX_OPTIMIZE);
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/* Set RAW flag only if pattern requires matching raw byte
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sequences. Otherwise, omit it so that GRegex treats its
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input as UTF8-encoded string. */
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if (raw_flag_needed(pattern)) {
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cflags = (GRegexCompileFlags)(cflags | G_REGEX_RAW);
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}
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/* Free up the old value, if we have one */
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gregex_fvalue_free(fv);
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fv->value.re = g_regex_new(
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pattern, /* pattern */
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cflags, /* Compile options */
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(GRegexMatchFlags)0, /* Match options */
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®ex_error /* Compile / study errors */
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);
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if (regex_error) {
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if (err_msg) {
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*err_msg = g_strdup(regex_error->message);
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}
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g_error_free(regex_error);
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if (fv->value.re) {
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g_regex_unref(fv->value.re);
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}
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return FALSE;
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}
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return TRUE;
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}
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/* Generate a FT_PCRE from an unparsed string pattern.
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* On failure, if err_msg is non-null, set *err_msg to point to a
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* g_malloc()ed error message. */
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static gboolean
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val_from_unparsed(fvalue_t *fv, const char *pattern, gboolean allow_partial_value, gchar **err_msg)
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{
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g_assert(! allow_partial_value);
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return val_from_string(fv, pattern, err_msg);
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}
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static int
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gregex_repr_len(fvalue_t *fv, ftrepr_t rtype, int field_display _U_)
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{
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g_assert(rtype == FTREPR_DFILTER);
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return (int)strlen(g_regex_get_pattern(fv->value.re));
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}
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static void
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gregex_to_repr(fvalue_t *fv, ftrepr_t rtype, int field_display _U_, char *buf, unsigned int size)
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{
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g_assert(rtype == FTREPR_DFILTER);
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g_strlcpy(buf, g_regex_get_pattern(fv->value.re), size);
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}
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/* BEHOLD - value contains the string representation of the regular expression,
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* and we want to store the compiled PCRE RE object into the value. */
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static void
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gregex_fvalue_set(fvalue_t *fv, const char *value)
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{
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g_assert(value != NULL);
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/* Free up the old value, if we have one */
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gregex_fvalue_free(fv);
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val_from_unparsed(fv, value, FALSE, NULL);
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}
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static gpointer
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gregex_fvalue_get(fvalue_t *fv)
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{
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return fv->value.re;
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}
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void
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ftype_register_pcre(void)
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{
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static ftype_t pcre_type = {
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FT_PCRE, /* ftype */
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"FT_PCRE", /* name */
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"Compiled Perl-Compatible Regular Expression (GRegex) object", /* pretty_name */
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0, /* wire_size */
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gregex_fvalue_new, /* new_value */
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gregex_fvalue_free, /* free_value */
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val_from_unparsed, /* val_from_unparsed */
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val_from_string, /* val_from_string */
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gregex_to_repr, /* val_to_string_repr */
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gregex_repr_len, /* len_string_repr */
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{ .set_value_string = gregex_fvalue_set }, /* union set_value */
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{ .get_value_ptr = gregex_fvalue_get }, /* union get_value */
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NULL, /* cmp_eq */
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NULL, /* cmp_ne */
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NULL, /* cmp_gt */
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NULL, /* cmp_ge */
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NULL, /* cmp_lt */
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NULL, /* cmp_le */
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NULL, /* cmp_bitwise_and */
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NULL, /* cmp_contains */
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NULL, /* cmp_matches */
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NULL, /* len */
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NULL, /* slice */
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};
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ftype_register(FT_PCRE, &pcre_type);
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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: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* vi: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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