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From Lionel Ains: 

don't assume that a dissector handle has a protocol associated
	with it (there's none for the "OSI network layer" dissector, for
	example, as that dissector hands off to one of several protocols
	based on the NLPID);

	rename a few functions to have names that better explain what
	they do;

	have separate functions to show all the layer types (dissector
	tables) and to show all the protocols supported for a layer
	type, and have both of them take, as an argument, the standard
	I/O stream to which they should write;

	improve the parser for the "-d" option to give more information
	on errors;

	fix up some comments.

svn path=/trunk/; revision=7949
This commit is contained in:
Guy Harris 2003-06-30 00:58:18 +00:00
parent 98e7c94dc1
commit 4cdfa9c59e
1 changed files with 138 additions and 69 deletions
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207
tethereal.c
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@ -1,6 +1,6 @@
/* tethereal.c
*
* $Id: tethereal.c,v 1.188 2003/06/22 16:06:03 deniel Exp $
* $Id: tethereal.c,v 1.189 2003/06/30 00:58:18 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
@ -415,38 +415,48 @@ register_ethereal_tap(char *cmd, void (*func)(char *arg))
}
/*
* For a dissector table, display, on the standard error, its short name
* (which is what's used in the "-d" option) and its descriptive name.
* For a dissector table, print on the stream described by output,
* its short name (which is what's used in the "-d" option) and its
* descriptive name.
*/
static void
display_dissector_table_names(char *table_name, char *ui_name,
gpointer user_data _U_)
display_dissector_table_names(char *table_name, char *ui_name, gpointer output)
{
fprintf(stderr, "\t%s (%s)\n", table_name, ui_name);
fprintf((FILE *)output, "\t%s (%s)\n", table_name, ui_name);
}
/*
* For a dissector handle, display, on the standard error, the filter name
* (which is what's used in the "-d" option) and the full name for the
* protocol for the handle.
* For a dissector handle, print on the stream described by output,
* the filter name (which is what's used in the "-d" option) and the full
* name for the protocol that corresponds to this handle.
*/
static void
display_dissector_names(gchar *table _U_, gpointer handle, gpointer data _U_)
display_dissector_names(gchar *table _U_, gpointer handle, gpointer output)
{
int proto_id;
const gchar* proto_filter_name;
const gchar* proto_ui_name;
proto_id = dissector_handle_get_protocol_index((dissector_handle_t)handle);
fprintf(stderr, "\t%s (%s)\n", proto_get_protocol_filter_name(proto_id),
proto_get_protocol_name(proto_id));
if (proto_id != -1) {
proto_filter_name = proto_get_protocol_filter_name(proto_id);
proto_ui_name = proto_get_protocol_name(proto_id);
g_assert(proto_filter_name != NULL);
g_assert(proto_ui_name != NULL);
fprintf((FILE *)output, "\t%s (%s)\n",
proto_filter_name,
proto_ui_name);
}
}
/*
* The protocol_name_search structure is used by find_name_shortname_func()
* The protocol_name_search structure is used by find_protocol_name_func()
* to pass parameters and store results
*/
struct protocol_name_search{
gchar *searched_name; /* Protocol name we are looking for */
gchar *searched_name; /* Protocol filter name we are looking for */
dissector_handle_t matched_handle; /* Handle for a dissector whose protocol has the specified filter name */
guint nb_match; /* How many dissectors matched searched_name */
};
@ -459,11 +469,12 @@ typedef struct protocol_name_search *protocol_name_search_t;
* The name we are looking for, as well as the results, are stored in the
* protocol_name_search struct pointed to by user_data.
* If called using dissector_table_foreach_handle, we actually parse the
* whole list of dissectors only once here.
* whole list of dissectors.
*/
static void
find_name_func(gchar *table _U_, gpointer handle, gpointer user_data) {
find_protocol_name_func(gchar *table _U_, gpointer handle, gpointer user_data)
{
int proto_id;
const gchar *protocol_filter_name;
protocol_name_search_t search_info;
@ -473,17 +484,47 @@ find_name_func(gchar *table _U_, gpointer handle, gpointer user_data) {
search_info = (protocol_name_search_t)user_data;
proto_id = dissector_handle_get_protocol_index((dissector_handle_t)handle);
protocol_filter_name = proto_get_protocol_filter_name(proto_id);
if (strcmp(protocol_filter_name, search_info->searched_name) == 0) {
/* Found a match */
if (search_info->nb_match == 0) {
/* Record this handle only if this is the first match */
search_info->matched_handle = (dissector_handle_t)handle; /* Record the handle for this matching dissector */
if (proto_id != -1) {
protocol_filter_name = proto_get_protocol_filter_name(proto_id);
g_assert(protocol_filter_name != NULL);
if (strcmp(protocol_filter_name, search_info->searched_name) == 0) {
/* Found a match */
if (search_info->nb_match == 0) {
/* Record this handle only if this is the first match */
search_info->matched_handle = (dissector_handle_t)handle; /* Record the handle for this matching dissector */
}
search_info->nb_match++;
}
search_info->nb_match++;
}
}
/*
* Print all layer type names supported.
* We send the output to the stream described by the handle output.
*/
static void
fprint_all_layer_types(FILE *output)
{
dissector_all_tables_foreach_table(display_dissector_table_names, (gpointer)output);
}
/*
* Print all protocol names supported for a specific layer type.
* table_name contains the layer type name in which the search is performed.
* We send the output to the stream described by the handle output.
*/
static void
fprint_all_protocols_for_layer_types(FILE *output, gchar *table_name)
{
dissector_table_foreach_handle(table_name,
display_dissector_names,
(gpointer)output);
}
/*
* The function below parses the command-line parameters for the decode as
* feature (a string pointer by cl_param).
@ -509,7 +550,7 @@ add_decode_as(const gchar *cl_param) {
/* The following code will allocate and copy the command-line options in a string pointed by decoded_param */
g_assert(cl_param);
decoded_param = g_malloc( sizeof(gchar) * strlen(cl_param) + 1 ); /* Allocate enough space to have a working copy of the command-line parameter */
decoded_param = g_malloc( sizeof(gchar) * (strlen(cl_param) + 1) ); /* Allocate enough space to have a working copy of the command-line parameter */
g_assert(decoded_param);
strcpy(decoded_param, cl_param);
@ -518,27 +559,19 @@ add_decode_as(const gchar *cl_param) {
necessary information. Note that decoded_param is still needed since
strings are not copied - we just save pointers. */
/* This section extracts a layer type (table_name) from decoded_param */
table_name = decoded_param; /* Layer type string starts from beginning */
remaining_param = strchr(table_name, '=');
if (remaining_param == NULL) {
fprintf(stderr, "tethereal: Parameter \"%s\" doesn't follow the template \"%s\"\n", cl_param, decode_as_arg_template);
g_free(decoded_param);
return FALSE;
}
*remaining_param = '\0'; /* Terminate the layer type string (table_name) where '=' was detected */
if (*(remaining_param + 1) != '=') { /* Check for "==" and not only '=' */
fprintf(stderr, "tethereal: Warning: -d requires \"==\" instead of \"=\". Option will be treated as \"%s==%s\"\n", table_name, remaining_param + 1);
/* If the argument does not follow the template, carry on anyway to check
if the table name is at least correct. If remaining_param is NULL,
we'll exit anyway further down */
}
else {
remaining_param++; /* Move to the second '=' */
*remaining_param = '\0'; /* Remove the second '=' */
*remaining_param = '\0'; /* Terminate the layer type string (table_name) where '=' was detected */
}
remaining_param++; /* Position after the layer type string */
selector_str = remaining_param; /* Next part starts with the selector number */
/* Remove leading and trailing spaces from the table name */
while ( table_name[0] == ' ' )
@ -546,22 +579,7 @@ add_decode_as(const gchar *cl_param) {
while ( table_name[strlen(table_name) - 1] == ' ' )
table_name[strlen(table_name) - 1] = '\0'; /* Note: if empty string, while loop will eventually exit */
remaining_param = strchr(selector_str, ',');
if (remaining_param == NULL) {
fprintf(stderr, "tethereal: Parameter \"%s\" doesn't follow the template \"%s\"\n", cl_param, decode_as_arg_template);
g_free(decoded_param);
return FALSE;
}
*remaining_param = '\0'; /* Terminate the selector number string (selector_str) where ',' was detected */
remaining_param++; /* Position after the selector number string */
dissector_str = remaining_param; /* All the rest of the string is the dissector (decode as protocol) name */
/* The following part looks for the layer type part of the parameter */
/* The following part searches a table matching with the layer type specified */
table_matching = NULL;
/* Look for the requested table */
@ -576,12 +594,41 @@ add_decode_as(const gchar *cl_param) {
}
if (!table_matching) {
/* Display a list of supported layer types to help the user, if the
specified layer type was not found */
fprintf(stderr, "tethereal: Valid layer types are:\n");
dissector_all_tables_foreach_table(display_dissector_table_names, NULL);
fprint_all_layer_types(stderr);
}
if (remaining_param == NULL || !table_matching) {
/* Exit if the layer type was not found, or if no '=' separator was found
(see above) */
g_free(decoded_param);
return FALSE;
}
if (*(remaining_param + 1) != '=') { /* Check for "==" and not only '=' */
fprintf(stderr, "tethereal: WARNING: -d requires \"==\" instead of \"=\". Option will be treated as \"%s==%s\"\n", table_name, remaining_param + 1);
}
else {
remaining_param++; /* Move to the second '=' */
*remaining_param = '\0'; /* Remove the second '=' */
}
remaining_param++; /* Position after the layer type string */
/* This section extracts a selector value (selector_str) from decoded_param */
selector_str = remaining_param; /* Next part starts with the selector number */
remaining_param = strchr(selector_str, ',');
if (remaining_param == NULL) {
fprintf(stderr, "tethereal: Parameter \"%s\" doesn't follow the template \"%s\"\n", cl_param, decode_as_arg_template);
/* If the argument does not follow the template, carry on anyway to check
if the selector value is at least correct. If remaining_param is NULL,
we'll exit anyway further down */
}
else {
*remaining_param = '\0'; /* Terminate the selector number string (selector_str) where ',' was detected */
}
switch (get_dissector_table_type(table_name)) {
@ -606,23 +653,30 @@ add_decode_as(const gchar *cl_param) {
g_assert_not_reached();
}
if (remaining_param == NULL) {
/* Exit if no ',' separator was found (see above) */
fprintf(stderr, "tethereal: Valid protocols for layer type \"%s\" are:\n", table_name);
fprint_all_protocols_for_layer_types(stderr, table_name);
g_free(decoded_param);
return FALSE;
}
remaining_param++; /* Position after the selector number string */
/* This section extracts a protocol filter name (dissector_str) from decoded_param */
dissector_str = remaining_param; /* All the rest of the string is the dissector (decode as protocol) name */
/* Remove leading and trailing spaces from the dissector name */
while ( dissector_str[0] == ' ' )
dissector_str++;
while ( dissector_str[strlen(dissector_str) - 1] == ' ' )
dissector_str[strlen(dissector_str) - 1] = '\0'; /* Note: if empty string, while loop will eventually exit */
#ifdef DEBUG
fprintf(stderr, "tethereal: Debug info: table=\"%s\", selector=\"%d\", dissector=\"%s\"\n", table_name, selector, dissector_str); // For debug only!
#endif
/* The is the end of the code that parses the command-line options. All information have now been stored in the structure preference. All strings are still pointing to decoded_parm that needs to be kept in memory as long as preference is needed, and decoded_param needs to be deallocated at each exit point of this function */
dissector_matching = NULL;
/* We now have a pointer to the handle for the requested table inside the variable table_matching */
/* We now have a pointer to the handle for the requested table inside the variable table_matching */
if ( ! (*dissector_str) ) { /* Is the dissector name empty, if so, don't even search for a matching dissector and display all dissectors found for the selected table */
fprintf(stderr, "tethereal: No protocol name specified\n"); /* Note, we don't exit here, but dissector_matching will remain NULL, so we exit below */
}
@ -630,12 +684,13 @@ add_decode_as(const gchar *cl_param) {
user_protocol_name.nb_match = 0;
user_protocol_name.searched_name = dissector_str;
user_protocol_name.matched_handle = NULL;
dissector_table_foreach_handle(table_name, find_name_func, &user_protocol_name); /* Go and perform the search for this dissector in the this table's dissectors' names and shortnames */
dissector_table_foreach_handle(table_name, find_protocol_name_func, &user_protocol_name); /* Go and perform the search for this dissector in the this table's dissectors' names and shortnames */
if (user_protocol_name.nb_match != 0) {
dissector_matching = user_protocol_name.matched_handle;
if (user_protocol_name.nb_match > 1) {
fprintf(stderr, "tethereal: Warning: Protocol \"%s\" matched %u dissectors, first one will be used\n", dissector_str, user_protocol_name.nb_match);
fprintf(stderr, "tethereal: WARNING: Protocol \"%s\" matched %u dissectors, first one will be used\n", dissector_str, user_protocol_name.nb_match);
}
}
else {
@ -656,14 +711,28 @@ add_decode_as(const gchar *cl_param) {
if (!dissector_matching) {
fprintf(stderr, "tethereal: Valid protocols for layer type \"%s\" are:\n", table_name);
dissector_table_foreach_handle(table_name, display_dissector_names, NULL);
fprint_all_protocols_for_layer_types(stderr, table_name);
g_free(decoded_param);
return FALSE;
}
/* This is the end of the code that parses the command-line options.
All information is now stored in the variables:
table_name
selector
dissector_matching
The above variables that are strings are still pointing to areas within
decoded_parm. decoded_parm thus still needs to be kept allocated in
until we stop needing these variables
decoded_param will be deallocated at each exit point of this function */
/* We now have a pointer to the handle for the requested dissector
(requested protocol) inside the variable dissector_matching */
dissector_change(table_name, selector, dissector_matching);
/* Note: this assumes selector is an unsigned int, if not, a switch on
get_dissector_table_type(table_name), like the one used earlier in this
function, needs to be inserted here */
g_free(decoded_param); /* "Decode As" rule has been succesfully added */
return TRUE;
}