2 * Routines for packet disassembly
6 * Wireshark - Network traffic analyzer
7 * By Gerald Combs <gerald@wireshark.org>
8 * Copyright 1998 Gerald Combs
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version 2
13 * of the License, or (at your option) any later version.
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
43 #include "timestamp.h"
45 #include "atalk-utils.h"
46 #include "sna-utils.h"
47 #include "osi-utils.h"
50 #include "addr_resolv.h"
53 #include "epan_dissect.h"
56 #include <epan/reassemble.h>
57 #include <epan/stream.h>
59 static gint proto_malformed = -1;
60 static dissector_handle_t frame_handle = NULL;
61 static dissector_handle_t data_handle = NULL;
63 const true_false_string flags_set_truth = {
71 frame_handle = find_dissector("frame");
72 data_handle = find_dissector("data");
73 proto_malformed = proto_get_id_by_filter_name("malformed");
83 * Given a tvbuff, and a length from a packet header, adjust the length
84 * of the tvbuff to reflect the specified length.
87 set_actual_length(tvbuff_t *tvb, guint specified_len)
89 if (specified_len < tvb_reported_length(tvb)) {
90 /* Adjust the length of this tvbuff to include only the specified
93 The dissector above the one calling us (the dissector above is
94 probably us) may use that to determine how much of its packet
96 tvb_set_reported_length(tvb, specified_len);
100 /* Allow protocols to register "init" routines, which are called before
101 we make a pass through a capture file and dissect all its packets
102 (e.g., when we read in a new capture file, or run a "filter packets"
103 or "colorize packets" pass over the current capture file). */
104 static GSList *init_routines;
107 register_init_routine(void (*func)(void))
109 init_routines = g_slist_append(init_routines, (gpointer)func);
112 typedef void (*void_func_t)(void);
114 /* Initialize all data structures used for dissection. */
116 call_init_routine(gpointer routine, gpointer dummy _U_)
118 void_func_t func = (void_func_t)routine;
123 * XXX - for now, these are the same; the "init" routines free whatever
124 * stuff is left over from any previous dissection, and then initialize
127 * We should probably split that into "init" and "cleanup" routines, for
131 init_dissection(void)
133 /* Reclaim and reinitialize all memory of seasonal scope */
136 /* Initialize the table of conversations. */
137 epan_conversation_init();
139 /* Initialize the table of circuits. */
142 /* Initialize protocol-specific variables. */
143 g_slist_foreach(init_routines, &call_init_routine, NULL);
145 /* Initialize the common data structures for fragment reassembly.
146 Must be done *after* calling init routines, as those routines
147 may free up space for fragments, which they find by using the
148 data structures that "reassemble_init()" frees. */
151 /* Initialise the stream-handling tables */
156 cleanup_dissection(void)
161 /* Allow protocols to register a "cleanup" routine to be
162 * run after the initial sequential run through the packets.
163 * Note that the file can still be open after this; this is not
164 * the final cleanup. */
165 static GSList *postseq_cleanup_routines;
168 register_postseq_cleanup_routine(void_func_t func)
170 postseq_cleanup_routines = g_slist_append(postseq_cleanup_routines,
174 /* Call all the registered "postseq_cleanup" routines. */
176 call_postseq_cleanup_routine(gpointer routine, gpointer dummy _U_)
178 void_func_t func = (void_func_t)routine;
183 postseq_cleanup_all_protocols(void)
185 g_slist_foreach(postseq_cleanup_routines,
186 &call_postseq_cleanup_routine, NULL);
190 * Add a new data source to the list of data sources for a frame, given
191 * the tvbuff for the data source and its name.
194 add_new_data_source(packet_info *pinfo, tvbuff_t *tvb, const char *name)
198 src = ep_alloc(sizeof (data_source));
201 * XXX - if we require this argument to be a string constant,
202 * we don't need to allocate a buffer for a copy and make a
203 * copy, and wouldn't need to free the buffer, either.
205 src->name = ep_strdup_printf("%s (%u bytes)", name, tvb_length(tvb));
206 pinfo->data_src = g_slist_append(pinfo->data_src, src);
210 * Free up a frame's list of data sources.
213 free_data_sources(packet_info *pinfo)
215 g_slist_free(pinfo->data_src);
216 pinfo->data_src = NULL;
219 /* Allow dissectors to register a "final_registration" routine
220 * that is run like the proto_register_XXX() routine, but at the
221 * end of the epan_init() function; that is, *after* all other
222 * subsystems, like dfilters, have finished initializing. This is
223 * useful for dissector registration routines which need to compile
224 * display filters. dfilters can't initialize itself until all protocols
225 * have registered themselves. */
226 static GSList *final_registration_routines;
229 register_final_registration_routine(void (*func)(void))
231 final_registration_routines = g_slist_append(final_registration_routines,
235 /* Call all the registered "final_registration" routines. */
237 call_final_registration_routine(gpointer routine, gpointer dummy _U_)
239 void_func_t func = (void_func_t)routine;
245 final_registration_all_protocols(void)
247 g_slist_foreach(final_registration_routines,
248 &call_final_registration_routine, NULL);
252 /* Creates the top-most tvbuff and calls dissect_frame() */
254 dissect_packet(epan_dissect_t *edt, union wtap_pseudo_header *pseudo_header,
255 const guchar *pd, frame_data *fd, column_info *cinfo)
259 edt->pi.current_proto = "<Missing Protocol Name>";
260 edt->pi.cinfo = cinfo;
262 edt->pi.pseudo_header = pseudo_header;
263 edt->pi.data_src = NULL;
264 edt->pi.dl_src.type = AT_NONE;
265 edt->pi.dl_src.len = 0;
266 edt->pi.dl_src.data = NULL;
267 edt->pi.dl_dst.type = AT_NONE;
268 edt->pi.dl_dst.len = 0;
269 edt->pi.dl_dst.data = NULL;
270 edt->pi.net_src.type = AT_NONE;
271 edt->pi.net_src.len = 0;
272 edt->pi.net_src.data = NULL;
273 edt->pi.net_dst.type = AT_NONE;
274 edt->pi.net_dst.len = 0;
275 edt->pi.net_dst.data = NULL;
276 edt->pi.src.type = AT_NONE;
278 edt->pi.src.data = NULL;
279 edt->pi.dst.type = AT_NONE;
281 edt->pi.dst.data = NULL;
282 edt->pi.ethertype = 0;
284 edt->pi.ipxptype = 0;
285 edt->pi.ctype = CT_NONE;
286 edt->pi.circuit_id = 0;
287 edt->pi.noreassembly_reason = "";
288 edt->pi.fragmented = FALSE;
289 edt->pi.in_error_pkt = FALSE;
290 edt->pi.ptype = PT_NONE;
292 edt->pi.destport = 0;
293 edt->pi.match_port = 0;
294 edt->pi.match_string = NULL;
295 edt->pi.can_desegment = 0;
296 edt->pi.want_pdu_tracking = 0;
297 edt->pi.p2p_dir = P2P_DIR_UNKNOWN;
298 edt->pi.private_data = NULL;
305 edt->pi.dcectxid = 0;
306 edt->pi.dcetransporttype = -1;
307 edt->pi.decrypt_gssapi_tvb = 0;
308 edt->pi.gssapi_wrap_tvb = NULL;
309 edt->pi.gssapi_encrypted_tvb = NULL;
310 edt->pi.gssapi_decrypted_tvb = NULL;
311 edt->pi.layer_names = NULL;
312 edt->pi.link_number = 0;
313 edt->pi.annex_a_used = MTP2_ANNEX_A_USED_UNKNOWN;
316 edt->tvb = tvb_new_real_data(pd, fd->cap_len, fd->pkt_len);
317 /* Add this tvbuffer into the data_src list */
318 add_new_data_source(&edt->pi, edt->tvb, "Frame");
320 /* Even though dissect_frame() catches all the exceptions a
321 * sub-dissector can throw, dissect_frame() itself may throw
322 * a ReportedBoundsError in bizarre cases. Thus, we catch the exception
323 * in this function. */
324 if(frame_handle != NULL)
325 call_dissector(frame_handle, edt->tvb, &edt->pi, edt->tree);
329 g_assert_not_reached();
331 CATCH(ReportedBoundsError) {
332 if(proto_malformed != -1){
333 proto_tree_add_protocol_format(edt->tree, proto_malformed, edt->tvb, 0, 0,
334 "[Malformed Frame: Packet Length]" );
336 g_assert_not_reached();
341 fd->flags.visited = 1;
344 /*********************** code added for sub-dissector lookup *********************/
347 * An dissector handle.
349 struct dissector_handle {
350 const char *name; /* dissector name */
351 gboolean is_new; /* TRUE if new-style dissector */
356 protocol_t *protocol;
359 /* This function will return
360 * old style dissector :
361 * length of the payload or 1 of the payload is empty
363 * >0 this protocol was successfully dissected and this was this protocol.
364 * 0 this packet did not match this protocol.
366 * The only time this function will return 0 is if it is a new style dissector
367 * and if the dissector rejected the packet.
370 call_dissector_through_handle(dissector_handle_t handle, tvbuff_t *tvb,
371 packet_info *pinfo, proto_tree *tree)
373 const char *saved_proto;
376 saved_proto = pinfo->current_proto;
378 if (handle->protocol != NULL) {
379 pinfo->current_proto =
380 proto_get_protocol_short_name(handle->protocol);
383 if (handle->is_new) {
384 ret = (*handle->dissector.new)(tvb, pinfo, tree);
386 (*handle->dissector.old)(tvb, pinfo, tree);
387 ret = tvb_length(tvb);
390 * XXX - a tvbuff can have 0 bytes of data in
391 * it, so we have to make sure we don't return
398 pinfo->current_proto = saved_proto;
404 * Call a dissector through a handle.
405 * If the protocol for that handle isn't enabled, return 0 without
406 * calling the dissector.
407 * Otherwise, if the handle refers to a new-style dissector, call the
408 * dissector and return its return value, otherwise call it and return
409 * the length of the tvbuff pointed to by the argument.
412 call_dissector_work(dissector_handle_t handle, tvbuff_t *tvb,
413 packet_info *pinfo_arg, proto_tree *tree)
415 packet_info *volatile pinfo = pinfo_arg;
416 const char *saved_proto;
417 guint16 saved_can_desegment;
418 volatile int ret = 0;
419 gboolean save_writable;
420 volatile address save_dl_src;
421 volatile address save_dl_dst;
422 volatile address save_net_src;
423 volatile address save_net_dst;
424 volatile address save_src;
425 volatile address save_dst;
426 volatile gint saved_layer_names_len = 0;
428 if (handle->protocol != NULL &&
429 !proto_is_protocol_enabled(handle->protocol)) {
431 * The protocol isn't enabled.
436 saved_proto = pinfo->current_proto;
437 saved_can_desegment = pinfo->can_desegment;
439 if (pinfo->layer_names != NULL)
440 saved_layer_names_len = pinfo->layer_names->len;
443 * can_desegment is set to 2 by anyone which offers the
444 * desegmentation api/service.
445 * Then everytime a subdissector is called it is decremented
447 * Thus only the subdissector immediately on top of whoever
448 * offers this service can use it.
449 * We save the current value of "can_desegment" for the
450 * benefit of TCP proxying dissectors such as SOCKS, so they
451 * can restore it and allow the dissectors they call to use
452 * the desegmentation service.
454 pinfo->saved_can_desegment = saved_can_desegment;
455 pinfo->can_desegment = saved_can_desegment-(saved_can_desegment>0);
456 if (handle->protocol != NULL) {
457 pinfo->current_proto =
458 proto_get_protocol_short_name(handle->protocol);
461 * Add the protocol name to the layers
463 if (pinfo->layer_names) {
464 if (pinfo->layer_names->len > 0)
465 g_string_append(pinfo->layer_names, ":");
466 g_string_append(pinfo->layer_names,
467 proto_get_protocol_filter_name(proto_get_id(handle->protocol)));
471 if (pinfo->in_error_pkt) {
473 * This isn't a packet being transported inside
474 * the protocol whose dissector is calling us,
475 * it's a copy of a packet that caused an error
476 * in some protocol included in a packet that
477 * reports the error (e.g., an ICMP Unreachable
482 * Save the current state of the writability of
483 * the columns, and restore them after the
484 * dissector returns, so that the columns
485 * don't reflect the packet that got the error,
486 * they reflect the packet that reported the
489 save_writable = col_get_writable(pinfo->cinfo);
490 col_set_writable(pinfo->cinfo, FALSE);
491 save_dl_src = pinfo->dl_src;
492 save_dl_dst = pinfo->dl_dst;
493 save_net_src = pinfo->net_src;
494 save_net_dst = pinfo->net_dst;
495 save_src = pinfo->src;
496 save_dst = pinfo->dst;
498 /* Dissect the contained packet. */
500 ret = call_dissector_through_handle(handle, tvb,
505 * Restore the column writability and addresses.
507 col_set_writable(pinfo->cinfo, save_writable);
508 pinfo->dl_src = save_dl_src;
509 pinfo->dl_dst = save_dl_dst;
510 pinfo->net_src = save_net_src;
511 pinfo->net_dst = save_net_dst;
512 pinfo->src = save_src;
513 pinfo->dst = save_dst;
516 * Restore the current protocol, so any
517 * "Short Frame" indication reflects that
518 * protocol, not the protocol for the
519 * packet that got the error.
521 pinfo->current_proto = saved_proto;
524 * Restore the desegmentability state.
526 pinfo->can_desegment = saved_can_desegment;
529 * Rethrow the exception, so this will be
530 * reported as a short frame.
534 CATCH(ReportedBoundsError) {
536 * "ret" wasn't set because an exception was thrown
537 * before "call_dissector_through_handle()" returned.
538 * As it called something, at least one dissector
539 * accepted the packet, and, as an exception was
540 * thrown, not only was all the tvbuff dissected,
541 * a dissector tried dissecting past the end of
542 * the data in some tvbuff, so we'll assume that
543 * the entire tvbuff was dissected.
545 ret = tvb_length(tvb);
549 col_set_writable(pinfo->cinfo, save_writable);
550 pinfo->dl_src = save_dl_src;
551 pinfo->dl_dst = save_dl_dst;
552 pinfo->net_src = save_net_src;
553 pinfo->net_dst = save_net_dst;
554 pinfo->src = save_src;
555 pinfo->dst = save_dst;
556 pinfo->want_pdu_tracking = 0;
559 * Just call the subdissector.
561 ret = call_dissector_through_handle(handle, tvb, pinfo, tree);
566 * That dissector didn't accept the packet, so
567 * remove its protocol's name from the list
570 if (pinfo->layer_names != NULL) {
571 g_string_truncate(pinfo->layer_names,
572 saved_layer_names_len);
575 pinfo->current_proto = saved_proto;
576 pinfo->can_desegment = saved_can_desegment;
581 * An entry in the hash table portion of a dissector table.
584 dissector_handle_t initial;
585 dissector_handle_t current;
591 * "hash_table" is a hash table, indexed by port number, supplying
592 * a "struct dtbl_entry"; it records what dissector is assigned to
593 * that port number in that table.
595 * "dissector_handles" is a list of all dissectors that *could* be
596 * used in that table; not all of them are necessarily in the table,
597 * as they may be for protocols that don't have a fixed port number.
599 * "ui_name" is the name the dissector table has in the user interface.
601 * "type" is a field type giving the width of the port number for that
604 * "base" is the base in which to display the port number for that
607 struct dissector_table {
608 GHashTable *hash_table;
609 GSList *dissector_handles;
615 static GHashTable *dissector_tables = NULL;
617 /* Finds a dissector table by table name. */
619 find_dissector_table(const char *name)
621 g_assert(dissector_tables);
622 return g_hash_table_lookup( dissector_tables, name );
625 /* Find an entry in a uint dissector table. */
626 static dtbl_entry_t *
627 find_uint_dtbl_entry(dissector_table_t sub_dissectors, guint32 pattern)
629 switch (sub_dissectors->type) {
636 * You can do a port lookup in these tables.
642 * But you can't do a port lookup in any other types
645 g_assert_not_reached();
651 return g_hash_table_lookup(sub_dissectors->hash_table,
652 GUINT_TO_POINTER(pattern));
655 /* Add an entry to a uint dissector table. */
657 dissector_add(const char *name, guint32 pattern, dissector_handle_t handle)
659 dissector_table_t sub_dissectors = find_dissector_table( name);
660 dtbl_entry_t *dtbl_entry;
663 g_assert( sub_dissectors);
664 switch (sub_dissectors->type) {
671 * You can do a port lookup in these tables.
677 * But you can't do a port lookup in any other types
680 g_assert_not_reached();
683 dtbl_entry = g_malloc(sizeof (dtbl_entry_t));
684 dtbl_entry->current = handle;
685 dtbl_entry->initial = dtbl_entry->current;
687 /* do the table insertion */
688 g_hash_table_insert( sub_dissectors->hash_table,
689 GUINT_TO_POINTER( pattern), (gpointer)dtbl_entry);
692 * Now add it to the list of handles that could be used with this
693 * table, because it *is* being used with this table.
695 dissector_add_handle(name, handle);
698 /* Delete the entry for a dissector in a uint dissector table
699 with a particular pattern. */
701 /* NOTE: this doesn't use the dissector call variable. It is included to */
702 /* be consistant with the dissector_add and more importantly to be used */
703 /* if the technique of adding a temporary dissector is implemented. */
704 /* If temporary dissectors are deleted, then the original dissector must */
707 dissector_delete(const char *name, guint32 pattern,
708 dissector_handle_t handle _U_)
710 dissector_table_t sub_dissectors = find_dissector_table( name);
711 dtbl_entry_t *dtbl_entry;
714 g_assert( sub_dissectors);
719 dtbl_entry = find_uint_dtbl_entry(sub_dissectors, pattern);
721 if (dtbl_entry != NULL) {
725 g_hash_table_remove(sub_dissectors->hash_table,
726 GUINT_TO_POINTER(pattern));
729 * Now free up the entry.
735 /* Change the entry for a dissector in a uint dissector table
736 with a particular pattern to use a new dissector handle. */
738 dissector_change(const char *name, guint32 pattern, dissector_handle_t handle)
740 dissector_table_t sub_dissectors = find_dissector_table( name);
741 dtbl_entry_t *dtbl_entry;
744 g_assert( sub_dissectors);
747 * See if the entry already exists. If so, reuse it.
749 dtbl_entry = find_uint_dtbl_entry(sub_dissectors, pattern);
750 if (dtbl_entry != NULL) {
751 dtbl_entry->current = handle;
756 * Don't create an entry if there is no dissector handle - I.E. the
757 * user said not to decode something that wasn't being decoded
758 * in the first place.
763 dtbl_entry = g_malloc(sizeof (dtbl_entry_t));
764 dtbl_entry->initial = NULL;
765 dtbl_entry->current = handle;
767 /* do the table insertion */
768 g_hash_table_insert( sub_dissectors->hash_table,
769 GUINT_TO_POINTER( pattern), (gpointer)dtbl_entry);
772 /* Reset an entry in a uint dissector table to its initial value. */
774 dissector_reset(const char *name, guint32 pattern)
776 dissector_table_t sub_dissectors = find_dissector_table( name);
777 dtbl_entry_t *dtbl_entry;
780 g_assert( sub_dissectors);
785 dtbl_entry = find_uint_dtbl_entry(sub_dissectors, pattern);
787 if (dtbl_entry == NULL)
791 * Found - is there an initial value?
793 if (dtbl_entry->initial != NULL) {
794 dtbl_entry->current = dtbl_entry->initial;
796 g_hash_table_remove(sub_dissectors->hash_table,
797 GUINT_TO_POINTER(pattern));
802 /* Look for a given value in a given uint dissector table and, if found,
803 call the dissector with the arguments supplied, and return TRUE,
804 otherwise return FALSE. */
806 dissector_try_port(dissector_table_t sub_dissectors, guint32 port,
807 tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
809 dtbl_entry_t *dtbl_entry;
810 struct dissector_handle *handle;
811 guint32 saved_match_port;
814 dtbl_entry = find_uint_dtbl_entry(sub_dissectors, port);
815 if (dtbl_entry != NULL) {
817 * Is there currently a dissector handle for this entry?
819 handle = dtbl_entry->current;
820 if (handle == NULL) {
822 * No - pretend this dissector didn't exist,
823 * so that other dissectors might have a chance
824 * to dissect this packet.
830 * Save the current value of "pinfo->match_port",
831 * set it to the port that matched, call the
832 * dissector, and restore "pinfo->match_port".
834 saved_match_port = pinfo->match_port;
835 pinfo->match_port = port;
836 ret = call_dissector_work(handle, tvb, pinfo, tree);
837 pinfo->match_port = saved_match_port;
840 * If a new-style dissector returned 0, it means that
841 * it didn't think this tvbuff represented a packet for
842 * its protocol, and didn't dissect anything.
844 * Old-style dissectors can't reject the packet.
846 * 0 is also returned if the protocol wasn't enabled.
848 * If the packet was rejected, we return FALSE, so that
849 * other dissectors might have a chance to dissect this
850 * packet, otherwise we return TRUE.
857 /* Look for a given value in a given uint dissector table and, if found,
858 return the dissector handle for that value. */
860 dissector_get_port_handle(dissector_table_t sub_dissectors, guint32 port)
862 dtbl_entry_t *dtbl_entry;
864 dtbl_entry = find_uint_dtbl_entry(sub_dissectors, port);
865 if (dtbl_entry != NULL)
866 return dtbl_entry->current;
871 /* Find an entry in a string dissector table. */
872 static dtbl_entry_t *
873 find_string_dtbl_entry(dissector_table_t sub_dissectors, const gchar *pattern)
875 switch (sub_dissectors->type) {
880 * You can do a string lookup in these tables.
886 * But you can't do a string lookup in any other types
889 g_assert_not_reached();
895 return g_hash_table_lookup(sub_dissectors->hash_table, pattern);
898 /* Add an entry to a string dissector table. */
900 dissector_add_string(const char *name, const gchar *pattern,
901 dissector_handle_t handle)
903 dissector_table_t sub_dissectors = find_dissector_table( name);
904 dtbl_entry_t *dtbl_entry;
907 g_assert( sub_dissectors);
909 switch (sub_dissectors->type) {
914 * You can do a string lookup in these tables.
920 * But you can't do a string lookup in any other types
923 g_assert_not_reached();
926 dtbl_entry = g_malloc(sizeof (dtbl_entry_t));
927 dtbl_entry->current = handle;
928 dtbl_entry->initial = dtbl_entry->current;
930 /* do the table insertion */
931 g_hash_table_insert( sub_dissectors->hash_table, (gpointer)pattern,
932 (gpointer)dtbl_entry);
935 * Now add it to the list of handles that could be used with this
936 * table, because it *is* being used with this table.
938 dissector_add_handle(name, handle);
941 /* Delete the entry for a dissector in a string dissector table
942 with a particular pattern. */
944 /* NOTE: this doesn't use the dissector call variable. It is included to */
945 /* be consistant with the dissector_add_string and more importantly to */
946 /* be used if the technique of adding a temporary dissector is */
948 /* If temporary dissectors are deleted, then the original dissector must */
951 dissector_delete_string(const char *name, const gchar *pattern,
952 dissector_handle_t handle _U_)
954 dissector_table_t sub_dissectors = find_dissector_table( name);
955 dtbl_entry_t *dtbl_entry;
958 g_assert( sub_dissectors);
963 dtbl_entry = find_string_dtbl_entry(sub_dissectors, pattern);
965 if (dtbl_entry != NULL) {
969 g_hash_table_remove(sub_dissectors->hash_table, pattern);
972 * Now free up the entry.
978 /* Change the entry for a dissector in a string dissector table
979 with a particular pattern to use a new dissector handle. */
981 dissector_change_string(const char *name, gchar *pattern,
982 dissector_handle_t handle)
984 dissector_table_t sub_dissectors = find_dissector_table( name);
985 dtbl_entry_t *dtbl_entry;
988 g_assert( sub_dissectors);
991 * See if the entry already exists. If so, reuse it.
993 dtbl_entry = find_string_dtbl_entry(sub_dissectors, pattern);
994 if (dtbl_entry != NULL) {
995 dtbl_entry->current = handle;
1000 * Don't create an entry if there is no dissector handle - I.E. the
1001 * user said not to decode something that wasn't being decoded
1002 * in the first place.
1007 dtbl_entry = g_malloc(sizeof (dtbl_entry_t));
1008 dtbl_entry->initial = NULL;
1009 dtbl_entry->current = handle;
1011 /* do the table insertion */
1012 g_hash_table_insert( sub_dissectors->hash_table, pattern,
1013 (gpointer)dtbl_entry);
1016 /* Reset an entry in a string sub-dissector table to its initial value. */
1018 dissector_reset_string(const char *name, const gchar *pattern)
1020 dissector_table_t sub_dissectors = find_dissector_table( name);
1021 dtbl_entry_t *dtbl_entry;
1024 g_assert( sub_dissectors);
1029 dtbl_entry = find_string_dtbl_entry(sub_dissectors, pattern);
1031 if (dtbl_entry == NULL)
1035 * Found - is there an initial value?
1037 if (dtbl_entry->initial != NULL) {
1038 dtbl_entry->current = dtbl_entry->initial;
1040 g_hash_table_remove(sub_dissectors->hash_table, pattern);
1045 /* Look for a given string in a given dissector table and, if found, call
1046 the dissector with the arguments supplied, and return TRUE, otherwise
1049 dissector_try_string(dissector_table_t sub_dissectors, const gchar *string,
1050 tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
1052 dtbl_entry_t *dtbl_entry;
1053 struct dissector_handle *handle;
1055 const gchar *saved_match_string;
1057 dtbl_entry = find_string_dtbl_entry(sub_dissectors, string);
1058 if (dtbl_entry != NULL) {
1060 * Is there currently a dissector handle for this entry?
1062 handle = dtbl_entry->current;
1063 if (handle == NULL) {
1065 * No - pretend this dissector didn't exist,
1066 * so that other dissectors might have a chance
1067 * to dissect this packet.
1073 * Save the current value of "pinfo->match_string",
1074 * set it to the string that matched, call the
1075 * dissector, and restore "pinfo->match_string".
1077 saved_match_string = pinfo->match_string;
1078 pinfo->match_string = string;
1079 ret = call_dissector_work(handle, tvb, pinfo, tree);
1080 pinfo->match_string = saved_match_string;
1083 * If a new-style dissector returned 0, it means that
1084 * it didn't think this tvbuff represented a packet for
1085 * its protocol, and didn't dissect anything.
1087 * Old-style dissectors can't reject the packet.
1089 * 0 is also returned if the protocol wasn't enabled.
1091 * If the packet was rejected, we return FALSE, so that
1092 * other dissectors might have a chance to dissect this
1093 * packet, otherwise we return TRUE.
1100 /* Look for a given value in a given string dissector table and, if found,
1101 return the dissector handle for that value. */
1103 dissector_get_string_handle(dissector_table_t sub_dissectors,
1104 const gchar *string)
1106 dtbl_entry_t *dtbl_entry;
1108 dtbl_entry = find_string_dtbl_entry(sub_dissectors, string);
1109 if (dtbl_entry != NULL)
1110 return dtbl_entry->current;
1116 dtbl_entry_get_handle (dtbl_entry_t *dtbl_entry)
1118 return dtbl_entry->current;
1121 /* Add a handle to the list of handles that *could* be used with this
1122 table. That list is used by code in the UI. */
1124 dissector_add_handle(const char *name, dissector_handle_t handle)
1126 dissector_table_t sub_dissectors = find_dissector_table( name);
1130 g_assert(sub_dissectors != NULL);
1132 /* Is it already in this list? */
1133 entry = g_slist_find(sub_dissectors->dissector_handles, (gpointer)handle);
1134 if (entry != NULL) {
1136 * Yes - don't insert it again.
1141 /* Add it to the list. */
1142 sub_dissectors->dissector_handles =
1143 g_slist_append(sub_dissectors->dissector_handles, (gpointer)handle);
1147 dtbl_entry_get_initial_handle (dtbl_entry_t *dtbl_entry)
1149 return dtbl_entry->initial;
1152 /**************************************************/
1154 /* Routines to walk dissector tables */
1156 /**************************************************/
1158 typedef struct dissector_foreach_info {
1159 gpointer caller_data;
1160 DATFunc caller_func;
1163 ftenum_t selector_type;
1164 } dissector_foreach_info_t;
1167 * Called for each entry in a dissector table.
1170 dissector_table_foreach_func (gpointer key, gpointer value, gpointer user_data)
1172 dissector_foreach_info_t *info;
1173 dtbl_entry_t *dtbl_entry;
1176 g_assert(user_data);
1179 if (dtbl_entry->current == NULL ||
1180 dtbl_entry->current->protocol == NULL) {
1182 * Either there is no dissector for this entry, or
1183 * the dissector doesn't have a protocol associated
1186 * XXX - should the latter check be done?
1192 info->caller_func(info->table_name, info->selector_type, key, value,
1197 * Called for each entry in the table of all dissector tables.
1200 dissector_all_tables_foreach_func (gpointer key, gpointer value, gpointer user_data)
1202 dissector_table_t sub_dissectors;
1203 dissector_foreach_info_t *info;
1206 g_assert(user_data);
1208 sub_dissectors = value;
1210 info->table_name = (gchar*) key;
1211 info->selector_type = get_dissector_table_selector_type(info->table_name);
1212 g_hash_table_foreach(sub_dissectors->hash_table, info->next_func, info);
1216 * Walk all dissector tables calling a user supplied function on each
1220 dissector_all_tables_foreach (DATFunc func,
1223 dissector_foreach_info_t info;
1225 info.caller_data = user_data;
1226 info.caller_func = func;
1227 info.next_func = dissector_table_foreach_func;
1228 g_hash_table_foreach(dissector_tables, dissector_all_tables_foreach_func, &info);
1232 * Walk one dissector table's hash table calling a user supplied function
1236 dissector_table_foreach (char *name,
1240 dissector_foreach_info_t info;
1241 dissector_table_t sub_dissectors = find_dissector_table( name);
1243 info.table_name = name;
1244 info.selector_type = sub_dissectors->type;
1245 info.caller_func = func;
1246 info.caller_data = user_data;
1247 g_hash_table_foreach(sub_dissectors->hash_table, dissector_table_foreach_func, &info);
1251 * Walk one dissector table's list of handles calling a user supplied
1252 * function on each entry.
1255 dissector_table_foreach_handle(const char *name,
1256 DATFunc_handle func,
1259 dissector_table_t sub_dissectors = find_dissector_table( name);
1262 for (tmp = sub_dissectors->dissector_handles; tmp != NULL;
1263 tmp = g_slist_next(tmp))
1264 func(name, tmp->data, user_data);
1268 * Called for each entry in a dissector table.
1271 dissector_table_foreach_changed_func (gpointer key, gpointer value, gpointer user_data)
1273 dtbl_entry_t *dtbl_entry;
1274 dissector_foreach_info_t *info;
1277 g_assert(user_data);
1280 if (dtbl_entry->initial == dtbl_entry->current) {
1282 * Entry hasn't changed - don't call the function.
1288 info->caller_func(info->table_name, info->selector_type, key, value,
1293 * Walk all dissector tables calling a user supplied function only on
1294 * any entry that has been changed from its original state.
1297 dissector_all_tables_foreach_changed (DATFunc func,
1300 dissector_foreach_info_t info;
1302 info.caller_data = user_data;
1303 info.caller_func = func;
1304 info.next_func = dissector_table_foreach_changed_func;
1305 g_hash_table_foreach(dissector_tables, dissector_all_tables_foreach_func, &info);
1309 * Walk one dissector table calling a user supplied function only on
1310 * any entry that has been changed from its original state.
1313 dissector_table_foreach_changed (char *name,
1317 dissector_foreach_info_t info;
1318 dissector_table_t sub_dissectors = find_dissector_table( name);
1320 info.table_name = name;
1321 info.selector_type = sub_dissectors->type;
1322 info.caller_func = func;
1323 info.caller_data = user_data;
1324 g_hash_table_foreach(sub_dissectors->hash_table,
1325 dissector_table_foreach_changed_func, &info);
1328 typedef struct dissector_foreach_table_info {
1329 gpointer caller_data;
1330 DATFunc_table caller_func;
1331 } dissector_foreach_table_info_t;
1334 * Called for each entry in the table of all dissector tables.
1337 dissector_all_tables_foreach_table_func (gpointer key, gpointer value, gpointer user_data)
1339 dissector_table_t table;
1340 dissector_foreach_table_info_t *info;
1344 (*info->caller_func)((gchar*)key, table->ui_name, info->caller_data);
1348 * Walk all dissector tables calling a user supplied function on each
1352 dissector_all_tables_foreach_table (DATFunc_table func,
1355 dissector_foreach_table_info_t info;
1357 info.caller_data = user_data;
1358 info.caller_func = func;
1359 g_hash_table_foreach(dissector_tables, dissector_all_tables_foreach_table_func, &info);
1363 register_dissector_table(const char *name, const char *ui_name, ftenum_t type,
1366 dissector_table_t sub_dissectors;
1368 /* Create our hash-of-hashes if it doesn't already exist */
1369 if (!dissector_tables) {
1370 dissector_tables = g_hash_table_new( g_str_hash, g_str_equal );
1371 g_assert(dissector_tables);
1374 /* Make sure the registration is unique */
1375 g_assert(!g_hash_table_lookup( dissector_tables, name ));
1377 /* Create and register the dissector table for this name; returns */
1378 /* a pointer to the dissector table. */
1379 sub_dissectors = g_malloc(sizeof (struct dissector_table));
1387 * XXX - there's no "g_uint_hash()" or "g_uint_equal()",
1388 * so we use "g_direct_hash()" and "g_direct_equal()".
1390 sub_dissectors->hash_table = g_hash_table_new( g_direct_hash,
1396 sub_dissectors->hash_table = g_hash_table_new( g_str_hash,
1401 g_assert_not_reached();
1403 sub_dissectors->dissector_handles = NULL;
1404 sub_dissectors->ui_name = ui_name;
1405 sub_dissectors->type = type;
1406 sub_dissectors->base = base;
1407 g_hash_table_insert( dissector_tables, (gpointer)name, (gpointer) sub_dissectors );
1408 return sub_dissectors;
1412 get_dissector_table_ui_name(const char *name)
1414 dissector_table_t sub_dissectors = find_dissector_table( name);
1416 return sub_dissectors->ui_name;
1420 get_dissector_table_selector_type(const char *name)
1422 dissector_table_t sub_dissectors = find_dissector_table( name);
1424 return sub_dissectors->type;
1428 get_dissector_table_base(const char *name)
1430 dissector_table_t sub_dissectors = find_dissector_table( name);
1432 return sub_dissectors->base;
1435 static GHashTable *heur_dissector_lists = NULL;
1438 heur_dissector_t dissector;
1439 protocol_t *protocol;
1440 } heur_dtbl_entry_t;
1442 /* Finds a heuristic dissector table by field name. */
1443 static heur_dissector_list_t *
1444 find_heur_dissector_list(const char *name)
1446 g_assert(heur_dissector_lists != NULL);
1447 return g_hash_table_lookup(heur_dissector_lists, name);
1451 heur_dissector_add(const char *name, heur_dissector_t dissector, int proto)
1453 heur_dissector_list_t *sub_dissectors = find_heur_dissector_list(name);
1454 heur_dtbl_entry_t *dtbl_entry;
1457 g_assert(sub_dissectors != NULL);
1459 dtbl_entry = g_malloc(sizeof (heur_dtbl_entry_t));
1460 dtbl_entry->dissector = dissector;
1461 dtbl_entry->protocol = find_protocol_by_id(proto);
1463 /* do the table insertion */
1464 *sub_dissectors = g_slist_append(*sub_dissectors, (gpointer)dtbl_entry);
1468 dissector_try_heuristic(heur_dissector_list_t sub_dissectors,
1469 tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
1472 const char *saved_proto;
1474 heur_dtbl_entry_t *dtbl_entry;
1475 guint16 saved_can_desegment;
1476 gint saved_layer_names_len = 0;
1478 /* can_desegment is set to 2 by anyone which offers this api/service.
1479 then everytime a subdissector is called it is decremented by one.
1480 thus only the subdissector immediately ontop of whoever offers this
1482 We save the current value of "can_desegment" for the
1483 benefit of TCP proxying dissectors such as SOCKS, so they
1484 can restore it and allow the dissectors they call to use
1485 the desegmentation service.
1487 saved_can_desegment=pinfo->can_desegment;
1488 pinfo->saved_can_desegment = saved_can_desegment;
1489 pinfo->can_desegment = saved_can_desegment-(saved_can_desegment>0);
1492 saved_proto = pinfo->current_proto;
1494 if (pinfo->layer_names != NULL)
1495 saved_layer_names_len = pinfo->layer_names->len;
1497 for (entry = sub_dissectors; entry != NULL; entry = g_slist_next(entry)) {
1498 /* XXX - why set this now and above? */
1499 pinfo->can_desegment = saved_can_desegment-(saved_can_desegment>0);
1500 dtbl_entry = (heur_dtbl_entry_t *)entry->data;
1502 if (dtbl_entry->protocol != NULL &&
1503 !proto_is_protocol_enabled(dtbl_entry->protocol)) {
1505 * No - don't try this dissector.
1510 if (dtbl_entry->protocol != NULL) {
1511 pinfo->current_proto =
1512 proto_get_protocol_short_name(dtbl_entry->protocol);
1515 * Add the protocol name to the layers; we'll remove it
1516 * if the dissector fails.
1518 if (pinfo->layer_names) {
1519 if (pinfo->layer_names->len > 0)
1520 g_string_append(pinfo->layer_names, ":");
1521 g_string_append(pinfo->layer_names,
1522 proto_get_protocol_filter_name(proto_get_id(dtbl_entry->protocol)));
1526 if ((*dtbl_entry->dissector)(tvb, pinfo, tree)) {
1531 * That dissector didn't accept the packet, so
1532 * remove its protocol's name from the list
1535 if (pinfo->layer_names != NULL) {
1536 g_string_truncate(pinfo->layer_names,
1537 saved_layer_names_len);
1541 pinfo->current_proto = saved_proto;
1542 pinfo->can_desegment=saved_can_desegment;
1547 register_heur_dissector_list(const char *name, heur_dissector_list_t *sub_dissectors)
1549 /* Create our hash-of-lists if it doesn't already exist */
1550 if (heur_dissector_lists == NULL) {
1551 heur_dissector_lists = g_hash_table_new(g_str_hash, g_str_equal);
1552 g_assert(heur_dissector_lists != NULL);
1555 /* Make sure the registration is unique */
1556 g_assert(g_hash_table_lookup(heur_dissector_lists, name) == NULL);
1558 *sub_dissectors = NULL; /* initially empty */
1559 g_hash_table_insert(heur_dissector_lists, (gpointer)name,
1560 (gpointer) sub_dissectors);
1564 * Register dissectors by name; used if one dissector always calls a
1565 * particular dissector, or if it bases the decision of which dissector
1566 * to call on something other than a numerical value or on "try a bunch
1567 * of dissectors until one likes the packet".
1571 * List of registered dissectors.
1573 static GHashTable *registered_dissectors = NULL;
1575 /* Get the short name of the protocol for a dissector handle, if it has
1578 dissector_handle_get_short_name(dissector_handle_t handle)
1580 if (handle->protocol == NULL) {
1582 * No protocol (see, for example, the handle for
1583 * dissecting the set of protocols where the first
1584 * octet of the payload is an OSI network layer protocol
1589 return proto_get_protocol_short_name(handle->protocol);
1592 /* Get the index of the protocol for a dissector handle, if it has
1595 dissector_handle_get_protocol_index(dissector_handle_t handle)
1597 if (handle->protocol == NULL) {
1599 * No protocol (see, for example, the handle for
1600 * dissecting the set of protocols where the first
1601 * octet of the payload is an OSI network layer protocol
1606 return proto_get_id(handle->protocol);
1609 /* Find a registered dissector by name. */
1611 find_dissector(const char *name)
1613 g_assert(registered_dissectors != NULL);
1614 return g_hash_table_lookup(registered_dissectors, name);
1617 /* Create an anonymous handle for a dissector. */
1619 create_dissector_handle(dissector_t dissector, int proto)
1621 struct dissector_handle *handle;
1623 handle = g_malloc(sizeof (struct dissector_handle));
1624 handle->name = NULL;
1625 handle->is_new = FALSE;
1626 handle->dissector.old = dissector;
1627 handle->protocol = find_protocol_by_id(proto);
1633 new_create_dissector_handle(new_dissector_t dissector, int proto)
1635 struct dissector_handle *handle;
1637 handle = g_malloc(sizeof (struct dissector_handle));
1638 handle->name = NULL;
1639 handle->is_new = TRUE;
1640 handle->dissector.new = dissector;
1641 handle->protocol = find_protocol_by_id(proto);
1646 /* Register a dissector by name. */
1648 register_dissector(const char *name, dissector_t dissector, int proto)
1650 struct dissector_handle *handle;
1652 /* Create our hash table if it doesn't already exist */
1653 if (registered_dissectors == NULL) {
1654 registered_dissectors = g_hash_table_new(g_str_hash, g_str_equal);
1655 g_assert(registered_dissectors != NULL);
1658 /* Make sure the registration is unique */
1659 g_assert(g_hash_table_lookup(registered_dissectors, name) == NULL);
1661 handle = g_malloc(sizeof (struct dissector_handle));
1662 handle->name = name;
1663 handle->is_new = FALSE;
1664 handle->dissector.old = dissector;
1665 handle->protocol = find_protocol_by_id(proto);
1667 g_hash_table_insert(registered_dissectors, (gpointer)name,
1672 new_register_dissector(const char *name, new_dissector_t dissector, int proto)
1674 struct dissector_handle *handle;
1676 /* Create our hash table if it doesn't already exist */
1677 if (registered_dissectors == NULL) {
1678 registered_dissectors = g_hash_table_new(g_str_hash, g_str_equal);
1679 g_assert(registered_dissectors != NULL);
1682 /* Make sure the registration is unique */
1683 g_assert(g_hash_table_lookup(registered_dissectors, name) == NULL);
1685 handle = g_malloc(sizeof (struct dissector_handle));
1686 handle->name = name;
1687 handle->is_new = TRUE;
1688 handle->dissector.new = dissector;
1689 handle->protocol = find_protocol_by_id(proto);
1691 g_hash_table_insert(registered_dissectors, (gpointer)name,
1695 /* Call a dissector through a handle and if this fails call the "data"
1699 call_dissector(dissector_handle_t handle, tvbuff_t *tvb,
1700 packet_info *pinfo, proto_tree *tree)
1704 ret = call_dissector_work(handle, tvb, pinfo, tree);
1707 * The protocol was disabled, or the dissector rejected
1708 * it. Just dissect this packet as data.
1710 g_assert(data_handle != NULL);
1711 g_assert(data_handle->protocol != NULL);
1712 call_dissector(data_handle, tvb, pinfo, tree);
1713 return tvb_length(tvb);
1718 /* Call a dissector through a handle but if the dissector rejected it
1719 * return 0 instead of using the default "data" dissector.
1722 call_dissector_only(dissector_handle_t handle, tvbuff_t *tvb,
1723 packet_info *pinfo, proto_tree *tree)
1727 ret = call_dissector_work(handle, tvb, pinfo, tree);
1732 * Dumps the "layer type"/"decode as" associations to stdout, similar
1733 * to the proto_registrar_dump_*() routines.
1735 * There is one record per line. The fields are tab-delimited.
1737 * Field 1 = layer type, e.g. "tcp.port"
1738 * Field 2 = selector in decimal
1739 * Field 3 = "decode as" name, e.g. "http"
1744 dissector_dump_decodes_display(gchar *table_name, ftenum_t selector_type _U_,
1745 gpointer key, gpointer value, gpointer user_data _U_)
1747 guint32 selector = (guint32) key;
1748 dissector_table_t sub_dissectors = find_dissector_table(table_name);
1749 dtbl_entry_t *dtbl_entry;
1750 dissector_handle_t handle;
1752 const gchar *decode_as;
1754 g_assert(sub_dissectors);
1755 switch (sub_dissectors->type) {
1762 g_assert(dtbl_entry);
1764 handle = dtbl_entry->current;
1767 proto_id = dissector_handle_get_protocol_index(handle);
1769 if (proto_id != -1) {
1770 decode_as = proto_get_protocol_filter_name(proto_id);
1771 g_assert(decode_as != NULL);
1772 printf("%s\t%u\t%s\n", table_name, selector, decode_as);
1782 dissector_dump_decodes() {
1783 dissector_all_tables_foreach(dissector_dump_decodes_display, NULL);
1786 static GPtrArray* post_dissectors = NULL;
1787 static guint num_of_postdissectors = 0;
1789 void register_postdissector(dissector_handle_t handle) {
1790 if (!post_dissectors)
1791 post_dissectors = g_ptr_array_new();
1793 g_ptr_array_add(post_dissectors, handle);
1794 num_of_postdissectors++;
1797 extern void call_all_postdissectors(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
1799 for(i=0;i<num_of_postdissectors;i++) {
1800 call_dissector((dissector_handle_t) g_ptr_array_index(post_dissectors,i),