epan/stream.c

   1 /* stream.c
   2  *
   3  * Definititions for handling circuit-switched protocols
   4  * which are handled as streams, and don't have lengths
   5  * and IDs such as are required for reassemble.h
   6  *
   7  * $Id$
   8  *
   9  * Wireshark - Network traffic analyzer
  10  * By Gerald Combs <gerald@wireshark.org>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  26  */
  27
  28 #include "config.h"
  29
  30 #include <glib.h>
  31 #include <epan/packet.h>
  32 #include <epan/emem.h>
  33 #include <epan/reassemble.h>
  34 #include <epan/stream.h>
  35 #include <epan/tvbuff.h>
  36
  37
  38 typedef struct {
  39     fragment_head *fd_head;          /* the reassembled data, NULL
  40                                       * until we add the last fragment */
  41     guint32 pdu_number;              /* Number of this PDU within the stream */
  42
  43     /* id of this pdu (globally unique) */
  44     guint32 id;
  45 } stream_pdu_t;
  46
  47
  48 struct stream_pdu_fragment
  49 {
  50     guint32 len;                     /* the length of this fragment */
  51     stream_pdu_t *pdu;
  52     gboolean final_fragment;
  53 };
  54
  55 struct stream {
  56     /* the key used to add this stream to stream_hash */
  57     struct stream_key *key;
  58
  59     /* pdu to add the next fragment to, or NULL if we need to start
  60      * a new PDU.
  61      */
  62     stream_pdu_t *current_pdu;
  63
  64     /* number of PDUs added to this stream so far */
  65     guint32 pdu_counter;
  66
  67     /* the framenumber and offset of the last fragment added;
  68        used for sanity-checking */
  69     guint32 lastfrag_framenum;
  70     guint32 lastfrag_offset;
  71 };
  72
  73
  74 /*****************************************************************************
  75  *
  76  * Stream hash
  77  */
  78
  79 /* key */
  80 typedef struct stream_key {
  81     /* streams can be attached to circuits or conversations, and we note
  82        that here */
  83     gboolean is_circuit;
  84     union {
  85         const struct circuit *circuit;
  86         const struct conversation *conv;
  87     } circ;
  88     int p2p_dir;
  89 } stream_key_t;
  90
  91
  92 /* hash func */
  93 static guint stream_hash_func(gconstpointer k)
  94 {
  95     const stream_key_t *key = (const stream_key_t *)k;
  96
  97     /* is_circuit is redundant to the circuit/conversation pointer */
  98     return ((guint)(unsigned long)key->circ.circuit) ^ key->p2p_dir;
  99 }
 100
 101 /* compare func */
 102 static gboolean stream_compare_func(gconstpointer a,
 103                              gconstpointer b)
 104 {
 105     const stream_key_t *key1 = (const stream_key_t *)a;
 106     const stream_key_t *key2 = (const stream_key_t *)b;
 107     if( key1 -> p2p_dir != key2 -> p2p_dir ||
 108         key1-> is_circuit != key2 -> is_circuit )
 109         return FALSE;
 110
 111     if( key1 -> is_circuit )
 112         return (key1 -> circ.circuit == key2 -> circ.circuit );
 113     else
 114         return (key1 -> circ.conv == key2 -> circ.conv );
 115 }
 116
 117 /* the hash table */
 118 static GHashTable *stream_hash;
 119
 120
 121 /* cleanup reset function, call from stream_cleanup() */
 122 static void cleanup_stream_hash( void ) {
 123     if( stream_hash != NULL ) {
 124         g_hash_table_destroy( stream_hash );
 125         stream_hash = NULL;
 126     }
 127 }
 128
 129 /* init function, call from stream_init() */
 130 static void init_stream_hash( void ) {
 131     g_assert(stream_hash==NULL);
 132     stream_hash = g_hash_table_new(stream_hash_func,
 133                                    stream_compare_func);
 134 }
 135
 136 /* lookup function, returns null if not found */
 137 static stream_t *stream_hash_lookup_circ( const struct circuit *circuit, int p2p_dir )
 138 {
 139     stream_key_t key;
 140     key.is_circuit=TRUE;
 141     key.circ.circuit=circuit;
 142     key.p2p_dir=p2p_dir;
 143     return (stream_t *)g_hash_table_lookup(stream_hash, &key);
 144 }
 145
 146 static stream_t *stream_hash_lookup_conv( const struct conversation *conv, int p2p_dir )
 147 {
 148     stream_key_t key;
 149     key.is_circuit=FALSE;
 150     key.circ.conv = conv;
 151     key.p2p_dir=p2p_dir;
 152     return (stream_t *)g_hash_table_lookup(stream_hash, &key);
 153 }
 154
 155
 156 static stream_t *new_stream( stream_key_t *key )
 157 {
 158     stream_t *val;
 159
 160     val = se_new(stream_t);
 161     val -> key = key;
 162     val -> pdu_counter = 0;
 163     val -> current_pdu = NULL;
 164     val -> lastfrag_framenum = 0;
 165     val -> lastfrag_offset = 0;
 166     g_hash_table_insert(stream_hash, key, val);
 167
 168     return val;
 169 }
 170
 171
 172 /* insert function */
 173 static stream_t *stream_hash_insert_circ( const struct circuit *circuit, int p2p_dir )
 174 {
 175     stream_key_t *key;
 176
 177     key = se_new(stream_key_t);
 178     key->is_circuit = TRUE;
 179     key->circ.circuit = circuit;
 180     key->p2p_dir = p2p_dir;
 181
 182     return new_stream(key);
 183 }
 184
 185 static stream_t *stream_hash_insert_conv( const struct conversation *conv, int p2p_dir )
 186 {
 187     stream_key_t *key;
 188
 189     key = se_new(stream_key_t);
 190     key->is_circuit = FALSE;
 191     key->circ.conv = conv;
 192     key->p2p_dir = p2p_dir;
 193
 194     return new_stream(key);
 195 }
 196
 197
 198 /******************************************************************************
 199  *
 200  * PDU data
 201  */
 202
 203 /* pdu counter, for generating unique pdu ids */
 204 static guint32 pdu_counter;
 205
 206 static void stream_cleanup_pdu_data(void)
 207 {
 208 }
 209
 210 static void stream_init_pdu_data(void)
 211 {
 212     pdu_counter = 0;
 213 }
 214
 215
 216 /* new pdu in this stream */
 217 static stream_pdu_t *stream_new_pdu(stream_t *stream)
 218 {
 219     stream_pdu_t *pdu;
 220     pdu = se_new(stream_pdu_t);
 221     pdu -> fd_head = NULL;
 222     pdu -> pdu_number = stream -> pdu_counter++;
 223     pdu -> id = pdu_counter++;
 224     return pdu;
 225 }
 226
 227 /*****************************************************************************
 228  *
 229  * fragment hash
 230  */
 231
 232 /* key */
 233 typedef struct fragment_key {
 234     const stream_t *stream;
 235     guint32 framenum;
 236     guint32 offset;
 237 } fragment_key_t;
 238
 239
 240 /* hash func */
 241 static guint fragment_hash_func(gconstpointer k)
 242 {
 243     const fragment_key_t *key = (const fragment_key_t *)k;
 244     return ((guint)(unsigned long)key->stream) + ((guint)key -> framenum) + ((guint)key->offset);
 245 }
 246
 247 /* compare func */
 248 static gboolean fragment_compare_func(gconstpointer a,
 249                                gconstpointer b)
 250 {
 251     const fragment_key_t *key1 = (const fragment_key_t *)a;
 252     const fragment_key_t *key2 = (const fragment_key_t *)b;
 253     return (key1 -> stream == key2 -> stream &&
 254             key1 -> framenum == key2 -> framenum &&
 255             key1 -> offset == key2 -> offset );
 256 }
 257
 258 /* the hash table */
 259 static GHashTable *fragment_hash;
 260
 261
 262 /* cleanup function, call from stream_cleanup() */
 263 static void cleanup_fragment_hash( void ) {
 264     if( fragment_hash != NULL ) {
 265         g_hash_table_destroy( fragment_hash );
 266         fragment_hash = NULL;
 267     }
 268 }
 269
 270 /* init function, call from stream_init() */
 271 static void init_fragment_hash( void ) {
 272     g_assert(fragment_hash==NULL);
 273     fragment_hash = g_hash_table_new(fragment_hash_func,
 274                                      fragment_compare_func);
 275 }
 276
 277
 278 /* lookup function, returns null if not found */
 279 static stream_pdu_fragment_t *fragment_hash_lookup( const stream_t *stream, guint32 framenum, guint32 offset )
 280 {
 281     fragment_key_t key;
 282     stream_pdu_fragment_t *val;
 283
 284     key.stream = stream;
 285     key.framenum = framenum;
 286     key.offset = offset;
 287     val = (stream_pdu_fragment_t *)g_hash_table_lookup(fragment_hash, &key);
 288
 289     return val;
 290 }
 291
 292
 293 /* insert function */
 294 static stream_pdu_fragment_t *fragment_hash_insert( const stream_t *stream, guint32 framenum, guint32 offset,
 295                                                     guint32 length)
 296 {
 297     fragment_key_t *key;
 298     stream_pdu_fragment_t *val;
 299
 300     key = se_new(fragment_key_t);
 301     key->stream = stream;
 302     key->framenum = framenum;
 303     key->offset = offset;
 304
 305     val = se_new(stream_pdu_fragment_t);
 306     val->len = length;
 307     val->pdu = NULL;
 308     val->final_fragment = FALSE;
 309
 310     g_hash_table_insert(fragment_hash, key, val);
 311     return val;
 312 }
 313
 314 /*****************************************************************************/
 315
 316 /* reassembly table */
 317 static reassembly_table stream_reassembly_table;
 318
 319 /* Initialise a new stream. Call this when you first identify a distinct
 320  * stream. */
 321 stream_t *stream_new_circ ( const struct circuit *circuit, int p2p_dir )
 322 {
 323     stream_t * stream;
 324
 325     /* we don't want to replace the previous data if we get called twice on the
 326        same circuit, so do a lookup first */
 327     stream = stream_hash_lookup_circ(circuit, p2p_dir);
 328     DISSECTOR_ASSERT( stream == NULL );
 329
 330     stream = stream_hash_insert_circ(circuit, p2p_dir);
 331
 332     return stream;
 333 }
 334
 335 stream_t *stream_new_conv ( const struct conversation *conv, int p2p_dir )
 336 {
 337     stream_t * stream;
 338
 339     /* we don't want to replace the previous data if we get called twice on the
 340        same conversation, so do a lookup first */
 341     stream = stream_hash_lookup_conv(conv, p2p_dir);
 342     DISSECTOR_ASSERT( stream == NULL );
 343
 344     stream = stream_hash_insert_conv(conv, p2p_dir);
 345     return stream;
 346 }
 347
 348
 349 /* retrieve a previously-created stream.
 350  *
 351  * Returns null if no matching stream was found.
 352  */
 353 stream_t *find_stream_circ ( const struct circuit *circuit, int p2p_dir )
 354 {
 355     return stream_hash_lookup_circ(circuit,p2p_dir);
 356 }
 357 stream_t *find_stream_conv ( const struct conversation *conv, int p2p_dir )
 358 {
 359     return stream_hash_lookup_conv(conv,p2p_dir);
 360 }
 361
 362 /* cleanup the stream routines */
 363 /* Note: stream_cleanup must only be called when seasonal memory
 364  *       is also freed since the hash tables countain pointers to
 365  *       se_alloc'd memory.
 366  */
 367 void stream_cleanup( void )
 368 {
 369     cleanup_stream_hash();
 370     cleanup_fragment_hash();
 371     stream_cleanup_pdu_data();
 372 }
 373
 374 /* initialise the stream routines */
 375 void stream_init( void )
 376 {
 377     init_stream_hash();
 378     init_fragment_hash();
 379     stream_init_pdu_data();
 380
 381     reassembly_table_init(&stream_reassembly_table,
 382                           &addresses_reassembly_table_functions);
 383 }
 384
 385 /*****************************************************************************/
 386
 387 stream_pdu_fragment_t *stream_find_frag( stream_t *stream, guint32 framenum, guint32 offset )
 388 {
 389     return fragment_hash_lookup( stream, framenum, offset );
 390 }
 391
 392 stream_pdu_fragment_t *stream_add_frag( stream_t *stream, guint32 framenum, guint32 offset,
 393                                         tvbuff_t *tvb, packet_info *pinfo, gboolean more_frags )
 394 {
 395     fragment_head *fd_head;
 396     stream_pdu_t *pdu;
 397     stream_pdu_fragment_t *frag_data;
 398
 399     DISSECTOR_ASSERT(stream);
 400
 401     /* check that this fragment is at the end of the stream */
 402     DISSECTOR_ASSERT( framenum > stream->lastfrag_framenum ||
 403                       (framenum == stream->lastfrag_framenum && offset > stream->lastfrag_offset));
 404
 405
 406     pdu = stream->current_pdu;
 407     if( pdu == NULL ) {
 408         /* start a new pdu */
 409         pdu = stream->current_pdu = stream_new_pdu(stream);
 410     }
 411
 412     /* add it to the reassembly tables */
 413     fd_head = fragment_add_seq_next(&stream_reassembly_table,
 414                                     tvb, 0, pinfo, pdu->id, NULL,
 415                                     tvb_reported_length(tvb), more_frags);
 416     /* add it to our hash */
 417     frag_data = fragment_hash_insert( stream, framenum, offset, tvb_reported_length(tvb));
 418     frag_data -> pdu = pdu;
 419
 420     if( fd_head != NULL ) {
 421         /* if this was the last fragment, update the pdu data.
 422          */
 423         pdu -> fd_head = fd_head;
 424
 425         /* start a new pdu next time */
 426         stream->current_pdu = NULL;
 427
 428         frag_data -> final_fragment = TRUE;
 429     }
 430
 431     /* stashing the framenum and offset permit future sanity checks */
 432     stream -> lastfrag_framenum = framenum;
 433     stream -> lastfrag_offset = offset;
 434
 435     return frag_data;
 436 }
 437
 438
 439 tvbuff_t *stream_process_reassembled(
 440     tvbuff_t *tvb, int offset, packet_info *pinfo,
 441     const char *name, const stream_pdu_fragment_t *frag,
 442     const struct _fragment_items *fit,
 443     gboolean *update_col_infop, proto_tree *tree)
 444 {
 445     stream_pdu_t *pdu;
 446     DISSECTOR_ASSERT(frag);
 447     pdu = frag->pdu;
 448
 449     /* we handle non-terminal fragments ourselves, because
 450        reassemble.c messes them up */
 451     if(!frag->final_fragment) {
 452         if (pdu->fd_head != NULL && fit->hf_reassembled_in != NULL) {
 453             proto_tree_add_uint(tree,
 454                                 *(fit->hf_reassembled_in), tvb,
 455                                 0, 0, pdu->fd_head->reassembled_in);
 456         }
 457         return NULL;
 458     }
 459
 460     return process_reassembled_data(tvb, offset, pinfo, name, pdu->fd_head,
 461                                     fit, update_col_infop, tree);
 462 }
 463
 464 guint32 stream_get_frag_length( const stream_pdu_fragment_t *frag)
 465 {
 466     DISSECTOR_ASSERT( frag );
 467     return frag->len;
 468 }
 469
 470 fragment_head *stream_get_frag_data( const stream_pdu_fragment_t *frag)
 471 {
 472     DISSECTOR_ASSERT( frag );
 473     return frag->pdu->fd_head;
 474 }
 475
 476 guint32 stream_get_pdu_no( const stream_pdu_fragment_t *frag)
 477 {
 478     DISSECTOR_ASSERT( frag );
 479     return frag->pdu->pdu_number;
 480 }