forked from osmocom/wireshark
![João Valverde](/assets/img/avatar_default.png)
Make dfilter byte representation always use ':' for consistency. Make 1 byte be represented as "XX:" with the colon suffix to make it nonambiguous that is is a byte and not other type, like a protocol. The difference is can be seen in the following programs. In the before representation it is not obvious at all that the second "fc" value is a literal bytes value and not the value of the protocol "fc", although it can be inferred from the lack of a READ_TREE instruction. In the After we know that "fc:" must be bytes and not a protocol. Note that a leading colon is a syntactical expedient to say "this value with any type is a literal value and not a protocol field." A terminating colon is just a part of the dfilter literal bytes syntax. Before: Filter: fc == :fc Syntax tree: 0 TEST_ANY_EQ: 1 FIELD(fc <FT_PROTOCOL>) 1 FVALUE(fc <FT_PROTOCOL>) Instructions: 00000 READ_TREE fc <FT_PROTOCOL> -> reg#0 00001 IF_FALSE_GOTO 3 00002 ANY_EQ reg#0 == fc <FT_PROTOCOL> After: Filter: fc == :fc Syntax tree: 0 TEST_ANY_EQ: 1 FIELD(fc <FT_PROTOCOL>) 1 FVALUE(fc: <FT_PROTOCOL>) Instructions: 00000 READ_TREE fc <FT_PROTOCOL> -> reg#0 00001 IF_FALSE_GOTO 3 00002 ANY_EQ reg#0 == fc: <FT_PROTOCOL>
433 lines
9.9 KiB
C
433 lines
9.9 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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#include "config.h"
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#include <ftypes-int.h>
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#include <epan/strutil.h>
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#include <epan/to_str.h>
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#include <string.h>
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#include <wsutil/glib-compat.h>
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#include <epan/exceptions.h>
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#include <wsutil/ws_assert.h>
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static void
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value_new(fvalue_t *fv)
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{
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fv->value.protocol.tvb = NULL;
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fv->value.protocol.proto_string = NULL;
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fv->value.protocol.tvb_is_private = FALSE;
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fv->value.protocol.length = -1;
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}
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static void
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value_copy(fvalue_t *dst, const fvalue_t *src)
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{
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dst->value.protocol.tvb = tvb_clone(src->value.protocol.tvb);
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dst->value.protocol.proto_string = g_strdup(src->value.protocol.proto_string);
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dst->value.protocol.tvb_is_private = TRUE;
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dst->value.protocol.length = src->value.protocol.length;
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}
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static void
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value_free(fvalue_t *fv)
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{
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if (fv->value.protocol.tvb && fv->value.protocol.tvb_is_private) {
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tvb_free_chain(fv->value.protocol.tvb);
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}
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g_free(fv->value.protocol.proto_string);
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}
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static void
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value_set(fvalue_t *fv, tvbuff_t *value, const gchar *name, int length)
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{
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if (value != NULL) {
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/* Free up the old value, if we have one */
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value_free(fv);
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/* Set the protocol description and an (optional, nullable) tvbuff. */
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fv->value.protocol.tvb = value;
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fv->value.protocol.proto_string = g_strdup(name);
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}
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fv->value.protocol.length = length;
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}
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static gboolean
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val_from_string(fvalue_t *fv, const char *s, size_t len, gchar **err_msg _U_)
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{
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tvbuff_t *new_tvb;
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guint8 *private_data;
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/* Free up the old value, if we have one */
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value_free(fv);
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if (len == 0)
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len = strlen(s);
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/* Make a tvbuff from the string. We can drop the
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* terminating NUL. */
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private_data = (guint8 *)g_memdup2(s, (guint)len);
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new_tvb = tvb_new_real_data(private_data,
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(guint)len, (gint)len);
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/* Let the tvbuff know how to delete the data. */
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tvb_set_free_cb(new_tvb, g_free);
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/* And let us know that we need to free the tvbuff */
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fv->value.protocol.tvb_is_private = TRUE;
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/* This "field" is a value, it has no protocol description, but
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* we might compare it to a protocol with NULL tvb.
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* (e.g., proto_expert) */
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fv->value.protocol.tvb = new_tvb;
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fv->value.protocol.proto_string = g_strdup("");
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fv->value.protocol.length = -1;
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return TRUE;
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}
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static gboolean
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val_from_literal(fvalue_t *fv, const char *s, gboolean allow_partial_value _U_, gchar **err_msg)
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{
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GByteArray *bytes;
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tvbuff_t *new_tvb;
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/* Free up the old value, if we have one */
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value_free(fv);
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fv->value.protocol.tvb = NULL;
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fv->value.protocol.proto_string = NULL;
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fv->value.protocol.length = -1;
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/* Does this look like a byte string? */
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bytes = byte_array_from_literal(s, err_msg);
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if (bytes != NULL) {
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/* Make a tvbuff from the bytes */
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new_tvb = tvb_new_real_data(bytes->data, bytes->len, bytes->len);
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/* Let the tvbuff know how to delete the data. */
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tvb_set_free_cb(new_tvb, g_free);
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/* Free GByteArray, but keep data. */
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g_byte_array_free(bytes, FALSE);
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/* And let us know that we need to free the tvbuff */
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fv->value.protocol.tvb_is_private = TRUE;
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fv->value.protocol.tvb = new_tvb;
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/* This "field" is a value, it has no protocol description, but
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* we might compare it to a protocol with NULL tvb.
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* (e.g., proto_expert) */
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fv->value.protocol.proto_string = g_strdup("");
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return TRUE;
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}
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/* Not a byte array, forget about it. */
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return FALSE;
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}
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static gboolean
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val_from_charconst(fvalue_t *fv, unsigned long num, gchar **err_msg)
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{
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GByteArray *bytes;
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tvbuff_t *new_tvb;
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/* Free up the old value, if we have one */
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value_free(fv);
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fv->value.protocol.tvb = NULL;
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fv->value.protocol.proto_string = NULL;
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fv->value.protocol.length = -1;
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/* Does this look like a byte string? */
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bytes = byte_array_from_charconst(num, err_msg);
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if (bytes != NULL) {
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/* Make a tvbuff from the bytes */
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new_tvb = tvb_new_real_data(bytes->data, bytes->len, bytes->len);
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/* Let the tvbuff know how to delete the data. */
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tvb_set_free_cb(new_tvb, g_free);
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/* Free GByteArray, but keep data. */
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g_byte_array_free(bytes, FALSE);
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/* And let us know that we need to free the tvbuff */
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fv->value.protocol.tvb_is_private = TRUE;
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fv->value.protocol.tvb = new_tvb;
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/* This "field" is a value, it has no protocol description, but
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* we might compare it to a protocol with NULL tvb.
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* (e.g., proto_expert) */
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fv->value.protocol.proto_string = g_strdup("");
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return TRUE;
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}
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/* Not a byte array, forget about it. */
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return FALSE;
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}
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static char *
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val_to_repr(wmem_allocator_t *scope, const fvalue_t *fv, ftrepr_t rtype, int field_display _U_)
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{
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guint length;
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char *volatile buf = NULL;
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if (rtype != FTREPR_DFILTER)
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return NULL;
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TRY {
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if (fv->value.protocol.length >= 0)
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length = fv->value.protocol.length;
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else
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length = tvb_captured_length(fv->value.protocol.tvb);
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if (length) {
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if (rtype == FTREPR_DFILTER)
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buf = bytes_to_dfilter_repr(scope, tvb_get_ptr(fv->value.protocol.tvb, 0, length), length);
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else
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buf = bytes_to_str_punct_maxlen(scope, tvb_get_ptr(fv->value.protocol.tvb, 0, length), length, ':', 0);
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}
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}
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CATCH_ALL {
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/* nothing */
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}
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ENDTRY;
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return buf;
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}
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static tvbuff_t *
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value_get(fvalue_t *fv)
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{
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if (fv->value.protocol.length < 0)
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return fv->value.protocol.tvb;
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return tvb_new_subset_length_caplen(fv->value.protocol.tvb, 0, fv->value.protocol.length, fv->value.protocol.length);
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}
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static guint
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len(fvalue_t *fv)
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{
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volatile guint length = 0;
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TRY {
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if (fv->value.protocol.tvb) {
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if (fv->value.protocol.length >= 0)
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length = fv->value.protocol.length;
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else
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length = tvb_captured_length(fv->value.protocol.tvb);
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}
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}
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CATCH_ALL {
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/* nothing */
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}
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ENDTRY;
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return length;
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}
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static void
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slice(fvalue_t *fv, GByteArray *bytes, guint offset, guint length)
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{
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const guint8* data;
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volatile guint len = length;
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if (fv->value.protocol.tvb) {
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if (fv->value.protocol.length >= 0 && (guint)fv->value.protocol.length < len) {
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len = fv->value.protocol.length;
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}
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TRY {
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data = tvb_get_ptr(fv->value.protocol.tvb, offset, len);
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g_byte_array_append(bytes, data, len);
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}
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CATCH_ALL {
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/* nothing */
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}
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ENDTRY;
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}
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}
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static int
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_tvbcmp(const protocol_value_t *a, const protocol_value_t *b)
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{
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guint a_len;
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guint b_len;
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if (a->length < 0)
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a_len = tvb_captured_length(a->tvb);
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else
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a_len = a->length;
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if (b->length < 0)
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b_len = tvb_captured_length(b->tvb);
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else
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b_len = b->length;
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if (a_len != b_len)
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return a_len < b_len ? -1 : 1;
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return memcmp(tvb_get_ptr(a->tvb, 0, a_len), tvb_get_ptr(b->tvb, 0, a_len), a_len);
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}
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static enum ft_result
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cmp_order(const fvalue_t *fv_a, const fvalue_t *fv_b, int *cmp)
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{
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const protocol_value_t *a = (const protocol_value_t *)&fv_a->value.protocol;
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const protocol_value_t *b = (const protocol_value_t *)&fv_b->value.protocol;
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volatile int c = 0;
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TRY {
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if ((a->tvb != NULL) && (b->tvb != NULL)) {
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c = _tvbcmp(a, b);
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} else {
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c = strcmp(a->proto_string, b->proto_string);
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}
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}
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CATCH_ALL {
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/* nothing */
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}
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ENDTRY;
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*cmp = c;
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return FT_OK;
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}
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static enum ft_result
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cmp_contains(const fvalue_t *fv_a, const fvalue_t *fv_b, gboolean *contains)
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{
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volatile gboolean yes = FALSE;
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TRY {
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/* First see if tvb exists for both sides */
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if ((fv_a->value.protocol.tvb != NULL) && (fv_b->value.protocol.tvb != NULL)) {
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if (tvb_find_tvb(fv_a->value.protocol.tvb, fv_b->value.protocol.tvb, 0) > -1) {
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yes = TRUE;
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}
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} else {
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/* Otherwise just compare strings */
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if ((strlen(fv_b->value.protocol.proto_string) != 0) &&
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strstr(fv_a->value.protocol.proto_string, fv_b->value.protocol.proto_string)) {
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yes = TRUE;
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}
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}
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}
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CATCH_ALL {
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/* nothing */
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}
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ENDTRY;
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*contains = yes;
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return FT_OK;
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}
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static enum ft_result
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cmp_matches(const fvalue_t *fv, const ws_regex_t *regex, gboolean *matches)
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{
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const protocol_value_t *a = (const protocol_value_t *)&fv->value.protocol;
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volatile gboolean rc = FALSE;
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const char *data = NULL; /* tvb data */
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guint32 tvb_len; /* tvb length */
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if (! regex) {
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return FT_BADARG;
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}
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TRY {
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if (a->tvb != NULL) {
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tvb_len = tvb_captured_length(a->tvb);
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data = (const char *)tvb_get_ptr(a->tvb, 0, tvb_len);
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rc = ws_regex_matches_length(regex, data, tvb_len);
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} else {
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rc = ws_regex_matches(regex, a->proto_string);
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}
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}
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CATCH_ALL {
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rc = FALSE;
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}
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ENDTRY;
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*matches = rc;
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return FT_OK;
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}
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static gboolean
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is_zero(const fvalue_t *fv)
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{
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const protocol_value_t *a = &fv->value.protocol;
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return a->tvb == NULL && a->proto_string == NULL;
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}
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void
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ftype_register_tvbuff(void)
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{
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static ftype_t protocol_type = {
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FT_PROTOCOL, /* ftype */
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"FT_PROTOCOL", /* name */
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"Protocol", /* pretty_name */
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0, /* wire_size */
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value_new, /* new_value */
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value_copy, /* copy_value */
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value_free, /* free_value */
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val_from_literal, /* val_from_literal */
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val_from_string, /* val_from_string */
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val_from_charconst, /* val_from_charconst */
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val_to_repr, /* val_to_string_repr */
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NULL, /* val_to_uinteger64 */
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NULL, /* val_to_sinteger64 */
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{ .set_value_protocol = value_set }, /* union set_value */
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{ .get_value_protocol = value_get }, /* union get_value */
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cmp_order,
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cmp_contains,
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cmp_matches,
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is_zero,
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NULL,
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len,
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slice,
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NULL,
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NULL, /* unary_minus */
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NULL, /* add */
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NULL, /* subtract */
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NULL, /* multiply */
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NULL, /* divide */
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NULL, /* modulo */
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};
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ftype_register(FT_PROTOCOL, &protocol_type);
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}
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void
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ftype_register_pseudofields_tvbuff(int proto)
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{
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static int hf_ft_protocol;
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static hf_register_info hf_ftypes[] = {
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{ &hf_ft_protocol,
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{ "FT_PROTOCOL", "_ws.ftypes.protocol",
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FT_PROTOCOL, BASE_NONE, NULL, 0x00,
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NULL, HFILL }
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},
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};
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proto_register_field_array(proto, hf_ftypes, array_length(hf_ftypes));
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}
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/*
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* Editor modelines - https://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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