wiretap/pppdump.c

   1 /* pppdump.c
   2  *
   3  * $Id$
   4  *
   5  * Copyright (c) 2000 by Gilbert Ramirez <gram@alumni.rice.edu>
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; either version 2
  10  * of the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  20  */
  21
  22 #include "config.h"
  23 #include "wtap-int.h"
  24 #include "buffer.h"
  25 #include "pppdump.h"
  26 #include "file_wrappers.h"
  27
  28 #include <glib.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #include <errno.h>
  32 #include <string.h>
  33
  34 /*
  35 pppdump records
  36 Daniel Thompson (STMicroelectronics) <daniel.thompson@st.com>
  37
  38 +------+
  39 | 0x07 |                              Reset time
  40 +------+------+------+------+
  41 |  t3  |  t2  |  t1  |  t0  |         t = time_t
  42 +------+------+------+------+
  43
  44 +------+
  45 | 0x06 |                              Time step (short)
  46 +------+
  47 |  ts  |                              ts = time step (tenths of seconds)
  48 +------+
  49
  50 +------+
  51 | 0x05 |                              Time step (long)
  52 +------+------+------+------+
  53 | ts3  | ts2  | ts1  | ts0  |         ts = time step (tenths of seconds)
  54 +------+------+------+------+
  55
  56 +------+
  57 | 0x04 |                              Receive deliminator (not seen in practice)
  58 +------+
  59
  60 +------+
  61 | 0x03 |                              Send deliminator (not seen in practice)
  62 +------+
  63
  64 +------+
  65 | 0x02 |                              Received data
  66 +------+------+
  67 |  n1  |  n0  |                       n = number of bytes following
  68 +------+------+
  69 |    data     |
  70 |             |
  71
  72 +------+
  73 | 0x01 |                              Sent data
  74 +------+------+
  75 |  n1  |  n0  |                       n = number of bytes following
  76 +------+------+
  77 |    data     |
  78 |             |
  79 */
  80
  81 #define PPPD_SENT_DATA          0x01
  82 #define PPPD_RECV_DATA          0x02
  83 #define PPPD_SEND_DELIM         0x03
  84 #define PPPD_RECV_DELIM         0x04
  85 #define PPPD_TIME_STEP_LONG     0x05
  86 #define PPPD_TIME_STEP_SHORT    0x06
  87 #define PPPD_RESET_TIME         0x07
  88
  89 /* this buffer must be at least (2*PPPD_MTU) + sizeof(ppp_header) +
  90  * sizeof(lcp_header) + sizeof(ipcp_header).  PPPD_MTU is *very* rarely
  91  * larger than 1500 so this value is fine.
  92  */
  93 #define PPPD_BUF_SIZE           8192
  94
  95 typedef enum {
  96         DIRECTION_SENT,
  97         DIRECTION_RECV
  98 } direction_enum;
  99
 100 static gboolean pppdump_read(wtap *wth, int *err, gchar **err_info,
 101         gint64 *data_offset);
 102 static gboolean pppdump_seek_read(wtap *wth, gint64 seek_off,
 103         struct wtap_pkthdr *phdr, Buffer *buf, int len,
 104         int *err, gchar **err_info);
 105
 106 /*
 107  * Information saved about a packet, during the initial sequential pass
 108  * through the file, to allow us to later re-read it when randomly
 109  * reading packets.
 110  *
 111  * "offset" is the offset in the file of the first data chunk containing data
 112  * from that packet; note that it may also contain data from previous
 113  * packets.
 114  *
 115  * "num_bytes_to_skip" is the number of bytes from previous packets in that
 116  * first data chunk.
 117  *
 118  * "dir" is the direction of the packet.
 119  */
 120 typedef struct {
 121         gint64          offset;
 122         gint64          num_bytes_to_skip;
 123         direction_enum  dir;
 124 } pkt_id;
 125
 126 /*
 127  * Information about a packet currently being processed.  There is one of
 128  * these for the sent packet being processed and one of these for the
 129  * received packet being processed, as we could be in the middle of
 130  * processing both a received packet and a sent packet.
 131  *
 132  * "dir" is the direction of the packet.
 133  *
 134  * "cnt" is the number of bytes of packet data we've accumulated.
 135  *
 136  * "esc" is TRUE if the next byte we see is escaped (and thus must be XORed
 137  * with 0x20 before saving it), FALSE otherwise.
 138  *
 139  * "buf" is a buffer containing the packet data we've accumulated.
 140  *
 141  * "id_offset" is the offset in the file of the first data chunk
 142  * containing data from the packet we're processing.
 143  *
 144  * "sd_offset" is the offset in the file of the first data byte from
 145  * the packet we're processing - which isn't necessarily right after
 146  * the header of the first data chunk, as we may already have assembled
 147  * packets from that chunk.
 148  *
 149  * "cd_offset" is the offset in the file of the current data chunk we're
 150  * processing.
 151  */
 152 typedef struct {
 153         direction_enum  dir;
 154         int             cnt;
 155         gboolean        esc;
 156         guint8          buf[PPPD_BUF_SIZE];
 157         gint64          id_offset;
 158         gint64          sd_offset;
 159         gint64          cd_offset;
 160 } pkt_t;
 161
 162 /*
 163  * This keeps state used while processing records.
 164  *
 165  * "timestamp" is the seconds portion of the current time stamp value,
 166  * as updated from PPPD_RESET_TIME, PPPD_TIME_STEP_LONG, and
 167  * PPPD_TIME_STEP_SHORT records.  "tenths" is the tenths-of-seconds
 168  * portion.
 169  *
 170  * "spkt" and "rpkt" are "pkt_t" structures for the sent and received
 171  * packets we're currently working on.
 172  *
 173  * "offset" is the current offset in the file.
 174  *
 175  * "num_bytes" and "pkt" are information saved when we finish accumulating
 176  * the data for a packet, if the data chunk we're working on still has more
 177  * data in it:
 178  *
 179  *      "num_bytes" is the number of bytes of additional data remaining
 180  *      in the chunk after we've finished accumulating the data for the
 181  *      packet.
 182  *
 183  *      "pkt" is the "pkt_t" for the type of packet the data chunk is for
 184  *      (sent or received packet).
 185  *
 186  * "seek_state" is another state structure used while processing records
 187  * when doing a seek-and-read.  (That structure doesn't itself have a
 188  * "seek_state" structure.)
 189  *
 190  * "pids" is a GPtrArray of pointers to "pkt_id" structures for all the
 191  * packets we've seen during the initial sequential pass, to allow us to
 192  * later retrieve them with random accesses.
 193  *
 194  * "pkt_cnt" is the number of packets we've seen up to this point in the
 195  * sequential pass.
 196  */
 197 typedef struct _pppdump_t {
 198         time_t                  timestamp;
 199         guint                   tenths;
 200         pkt_t                   spkt;
 201         pkt_t                   rpkt;
 202         gint64                  offset;
 203         int                     num_bytes;
 204         pkt_t                   *pkt;
 205         struct _pppdump_t       *seek_state;
 206         GPtrArray               *pids;
 207         guint                   pkt_cnt;
 208 } pppdump_t;
 209
 210 static int
 211 process_data(pppdump_t *state, FILE_T fh, pkt_t *pkt, int n, guint8 *pd,
 212     int *err, gchar **err_info, pkt_id *pid);
 213
 214 static gboolean
 215 collate(pppdump_t*, FILE_T fh, int *err, gchar **err_info, guint8 *pd,
 216                 int *num_bytes, direction_enum *direction, pkt_id *pid,
 217                 gint64 num_bytes_to_skip);
 218
 219 static void
 220 pppdump_close(wtap *wth);
 221
 222 static void
 223 init_state(pppdump_t *state)
 224 {
 225
 226         state->num_bytes = 0;
 227         state->pkt = NULL;
 228
 229         state->spkt.dir = DIRECTION_SENT;
 230         state->spkt.cnt = 0;
 231         state->spkt.esc = FALSE;
 232         state->spkt.id_offset = 0;
 233         state->spkt.sd_offset = 0;
 234         state->spkt.cd_offset = 0;
 235
 236         state->rpkt.dir = DIRECTION_RECV;
 237         state->rpkt.cnt = 0;
 238         state->rpkt.esc = FALSE;
 239         state->rpkt.id_offset = 0;
 240         state->rpkt.sd_offset = 0;
 241         state->rpkt.cd_offset = 0;
 242
 243         state->seek_state = NULL;
 244         state->offset = 0x100000; /* to detect errors during development */
 245 }
 246
 247
 248 int
 249 pppdump_open(wtap *wth, int *err, gchar **err_info)
 250 {
 251         guint8          buffer[6];      /* Looking for: 0x07 t3 t2 t1 t0 ID */
 252         int             bytes_read;
 253         pppdump_t       *state;
 254
 255         /* There is no file header, only packet records. Fortunately for us,
 256         * timestamp records are separated from packet records, so we should
 257         * find an "initial time stamp" (i.e., a "reset time" record, or
 258         * record type 0x07) at the beginning of the file. We'll check for
 259         * that, plus a valid record following the 0x07 and the four bytes
 260         * representing the timestamp.
 261         */
 262
 263         bytes_read = file_read(buffer, sizeof(buffer), wth->fh);
 264         if (bytes_read != (int) sizeof(buffer)) {
 265                 *err = file_error(wth->fh, err_info);
 266                 if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
 267                         return -1;
 268                 return 0;
 269         }
 270
 271         if (buffer[0] == PPPD_RESET_TIME &&
 272                         (buffer[5] == PPPD_SENT_DATA ||
 273                          buffer[5] == PPPD_RECV_DATA ||
 274                          buffer[5] == PPPD_TIME_STEP_LONG ||
 275                          buffer[5] == PPPD_TIME_STEP_SHORT ||
 276                          buffer[5] == PPPD_RESET_TIME)) {
 277
 278                 goto my_file_type;
 279         }
 280         else {
 281                 return 0;
 282         }
 283
 284   my_file_type:
 285
 286         if (file_seek(wth->fh, 5, SEEK_SET, err) == -1)
 287                 return -1;
 288
 289         state = (pppdump_t *)g_malloc(sizeof(pppdump_t));
 290         wth->priv = (void *)state;
 291         state->timestamp = pntohl(&buffer[1]);
 292         state->tenths = 0;
 293
 294         init_state(state);
 295
 296         state->offset = 5;
 297         wth->file_encap = WTAP_ENCAP_PPP_WITH_PHDR;
 298         wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_PPPDUMP;
 299
 300         wth->snapshot_length = PPPD_BUF_SIZE; /* just guessing */
 301         wth->subtype_read = pppdump_read;
 302         wth->subtype_seek_read = pppdump_seek_read;
 303         wth->subtype_close = pppdump_close;
 304         wth->tsprecision = WTAP_FILE_TSPREC_DSEC;
 305
 306         state->seek_state = g_new(pppdump_t,1);
 307
 308         /* If we have a random stream open, we're going to be reading
 309            the file randomly; set up a GPtrArray of pointers to
 310            information about how to retrieve the data for each packet. */
 311         if (wth->random_fh != NULL)
 312                 state->pids = g_ptr_array_new();
 313         else
 314                 state->pids = NULL;
 315         state->pkt_cnt = 0;
 316
 317         return 1;
 318 }
 319
 320 /* Set part of the struct wtap_pkthdr. */
 321 static void
 322 pppdump_set_phdr(struct wtap_pkthdr *phdr, int num_bytes,
 323     direction_enum direction)
 324 {
 325         phdr->len = num_bytes;
 326         phdr->caplen = num_bytes;
 327         phdr->pkt_encap = WTAP_ENCAP_PPP_WITH_PHDR;
 328
 329         phdr->pseudo_header.p2p.sent = (direction == DIRECTION_SENT ? TRUE : FALSE);
 330 }
 331
 332 /* Find the next packet and parse it; called from wtap_read(). */
 333 static gboolean
 334 pppdump_read(wtap *wth, int *err, gchar **err_info, gint64 *data_offset)
 335 {
 336         int             num_bytes;
 337         direction_enum  direction;
 338         guint8          *buf;
 339         pppdump_t       *state;
 340         pkt_id          *pid;
 341
 342         state = (pppdump_t *)wth->priv;
 343
 344         /* If we have a random stream open, allocate a structure to hold
 345            the information needed to read this packet's data again. */
 346         if (wth->random_fh != NULL) {
 347                 pid = g_new(pkt_id, 1);
 348                 if (!pid) {
 349                         *err = errno;   /* assume a malloc failed and set "errno" */
 350                         return FALSE;
 351                 }
 352                 pid->offset = 0;
 353         } else
 354                 pid = NULL;     /* sequential only */
 355
 356         buffer_assure_space(wth->frame_buffer, PPPD_BUF_SIZE);
 357         buf = buffer_start_ptr(wth->frame_buffer);
 358
 359         if (!collate(state, wth->fh, err, err_info, buf, &num_bytes, &direction,
 360             pid, 0)) {
 361                 if (pid != NULL)
 362                         g_free(pid);
 363                 return FALSE;
 364         }
 365
 366         if (pid != NULL)
 367                 pid->dir = direction;
 368
 369         if (pid != NULL)
 370                 g_ptr_array_add(state->pids, pid);
 371         /* The user's data_offset is not really an offset, but a packet number. */
 372         *data_offset = state->pkt_cnt;
 373         state->pkt_cnt++;
 374
 375         wth->phdr.presence_flags = WTAP_HAS_TS;
 376         wth->phdr.ts.secs       = state->timestamp;
 377         wth->phdr.ts.nsecs      = state->tenths * 100000000;
 378         pppdump_set_phdr(&wth->phdr, num_bytes, direction);
 379
 380         return TRUE;
 381 }
 382
 383 /* Returns number of bytes copied for record, -1 if failure.
 384  *
 385  * This is modeled after pppdump.c, the utility to parse pppd log files; it
 386  * comes with the ppp distribution.
 387  */
 388 static int
 389 process_data(pppdump_t *state, FILE_T fh, pkt_t *pkt, int n, guint8 *pd,
 390     int *err, gchar **err_info, pkt_id *pid)
 391 {
 392         int     c;
 393         int     num_bytes = n;
 394         int     num_written;
 395
 396         for (; num_bytes > 0; --num_bytes) {
 397                 c = file_getc(fh);
 398                 if (c == EOF) {
 399                         *err = file_error(fh, err_info);
 400                         if (*err == 0) {
 401                                 *err = WTAP_ERR_SHORT_READ;
 402                         }
 403                         return -1;
 404                 }
 405                 state->offset++;
 406                 switch (c) {
 407                         case 0x7e:
 408                                 /*
 409                                  * Flag Sequence for RFC 1662 HDLC-like
 410                                  * framing.
 411                                  *
 412                                  * As this is a raw trace of octets going
 413                                  * over the wire, and that might include
 414                                  * the login sequence, there is no
 415                                  * guarantee that *only* PPP traffic
 416                                  * appears in this file, so there is no
 417                                  * guarantee that the first 0x7e we see is
 418                                  * a start flag sequence, and therefore we
 419                                  * cannot safely ignore all characters up
 420                                  * to the first 0x7e, and therefore we
 421                                  * might end up with some bogus PPP
 422                                  * packets.
 423                                  */
 424                                 if (pkt->cnt > 0) {
 425                                         /*
 426                                          * We've seen stuff before this,
 427                                          * so this is the end of a frame.
 428                                          * Make a frame out of that stuff.
 429                                          */
 430                                         pkt->esc = FALSE;
 431
 432                                         num_written = pkt->cnt;
 433                                         pkt->cnt = 0;
 434                                         if (num_written <= 0) {
 435                                                 return 0;
 436                                         }
 437
 438                                         if (num_written > PPPD_BUF_SIZE) {
 439                                                 *err = WTAP_ERR_UNC_OVERFLOW;
 440                                                 return -1;
 441                                         }
 442
 443                                         memcpy(pd, pkt->buf, num_written);
 444
 445                                         /*
 446                                          * Remember the offset of the
 447                                          * first record containing data
 448                                          * for this packet, and how far
 449                                          * into that record to skip to
 450                                          * get to the beginning of the
 451                                          * data for this packet; the number
 452                                          * of bytes to skip into that record
 453                                          * is the file offset of the first
 454                                          * byte of this packet minus the
 455                                          * file offset of the first byte of
 456                                          * this record, minus 3 bytes for the
 457                                          * header of this record (which, if
 458                                          * we re-read this record, we will
 459                                          * process, not skip).
 460                                          */
 461                                         if (pid) {
 462                                                 pid->offset = pkt->id_offset;
 463                                                 pid->num_bytes_to_skip =
 464                                                     pkt->sd_offset - pkt->id_offset - 3;
 465                                                 g_assert(pid->num_bytes_to_skip >= 0);
 466                                         }
 467
 468                                         num_bytes--;
 469                                         if (num_bytes > 0) {
 470                                                 /*
 471                                                  * There's more data in this
 472                                                  * record.
 473                                                  * Set the initial data offset
 474                                                  * for the next packet.
 475                                                  */
 476                                                 pkt->id_offset = pkt->cd_offset;
 477                                                 pkt->sd_offset = state->offset;
 478                                         } else {
 479                                                 /*
 480                                                  * There is no more data in
 481                                                  * this record.
 482                                                  * Thus, we don't have the
 483                                                  * initial data offset for
 484                                                  * the next packet.
 485                                                  */
 486                                                 pkt->id_offset = 0;
 487                                                 pkt->sd_offset = 0;
 488                                         }
 489                                         state->num_bytes = num_bytes;
 490                                         state->pkt = pkt;
 491                                         return num_written;
 492                                 }
 493                                 break;
 494
 495                         case 0x7d:
 496                                 /*
 497                                  * Control Escape octet for octet-stuffed
 498                                  * RFC 1662 HDLC-like framing.
 499                                  */
 500                                 if (!pkt->esc) {
 501                                         /*
 502                                          * Control Escape not preceded by
 503                                          * Control Escape; discard it
 504                                          * but XOR the next octet with
 505                                          * 0x20.
 506                                          */
 507                                         pkt->esc = TRUE;
 508                                         break;
 509                                 }
 510                                 /*
 511                                  * Control Escape preceded by Control Escape;
 512                                  * treat it as an ordinary character,
 513                                  * by falling through.
 514                                  */
 515
 516                         default:
 517                                 if (pkt->esc) {
 518                                         /*
 519                                          * This character was preceded by
 520                                          * Control Escape, so XOR it with
 521                                          * 0x20, as per RFC 1662's octet-
 522                                          * stuffed framing, and clear
 523                                          * the flag saying that the
 524                                          * character should be escaped.
 525                                          */
 526                                         c ^= 0x20;
 527                                         pkt->esc = FALSE;
 528                                 }
 529
 530                                 if (pkt->cnt >= PPPD_BUF_SIZE) {
 531                                         *err = WTAP_ERR_UNC_OVERFLOW;
 532                                         return -1;
 533                                 }
 534                                 pkt->buf[pkt->cnt++] = c;
 535                                 break;
 536                 }
 537         }
 538
 539         /* we could have run out of bytes to read */
 540         return 0;
 541 }
 542
 543 /* Returns TRUE if packet data copied, FALSE if error occurred or EOF (no more records). */
 544 static gboolean
 545 collate(pppdump_t* state, FILE_T fh, int *err, gchar **err_info, guint8 *pd,
 546                 int *num_bytes, direction_enum *direction, pkt_id *pid,
 547                 gint64 num_bytes_to_skip)
 548 {
 549         int             id;
 550         pkt_t           *pkt = NULL;
 551         int             byte0, byte1;
 552         int             n, num_written = 0;
 553         gint64          start_offset;
 554         guint32         time_long;
 555         guint8          time_short;
 556
 557         /*
 558          * Process any data left over in the current record when doing
 559          * sequential processing.
 560          */
 561         if (state->num_bytes > 0) {
 562                 g_assert(num_bytes_to_skip == 0);
 563                 pkt = state->pkt;
 564                 num_written = process_data(state, fh, pkt, state->num_bytes,
 565                     pd, err, err_info, pid);
 566
 567                 if (num_written < 0) {
 568                         return FALSE;
 569                 }
 570                 else if (num_written > 0) {
 571                         *num_bytes = num_written;
 572                         *direction = pkt->dir;
 573                         return TRUE;
 574                 }
 575                 /* if 0 bytes written, keep processing */
 576         } else {
 577                 /*
 578                  * We didn't have any data left over, so the packet will
 579                  * start at the beginning of a record.
 580                  */
 581                 if (pid)
 582                         pid->num_bytes_to_skip = 0;
 583         }
 584
 585         /*
 586          * That didn't get all the data for this packet, so process
 587          * subsequent records.
 588          */
 589         start_offset = state->offset;
 590         while ((id = file_getc(fh)) != EOF) {
 591                 state->offset++;
 592                 switch (id) {
 593                         case PPPD_SENT_DATA:
 594                         case PPPD_RECV_DATA:
 595                                 pkt = id == PPPD_SENT_DATA ? &state->spkt : &state->rpkt;
 596
 597                                 /*
 598                                  * Save the offset of the beginning of
 599                                  * the current record.
 600                                  */
 601                                 pkt->cd_offset = state->offset - 1;
 602
 603                                 /*
 604                                  * Get the length of the record.
 605                                  */
 606                                 byte0 = file_getc(fh);
 607                                 if (byte0 == EOF)
 608                                         goto done;
 609                                 state->offset++;
 610                                 byte1 = file_getc(fh);
 611                                 if (byte1 == EOF)
 612                                         goto done;
 613                                 state->offset++;
 614                                 n = (byte0 << 8) | byte1;
 615
 616                                 if (pkt->id_offset == 0) {
 617                                         /*
 618                                          * We don't have the initial data
 619                                          * offset for this packet, which
 620                                          * means this is the first
 621                                          * data record for that packet.
 622                                          * Save the offset of the
 623                                          * beginning of that record and
 624                                          * the offset of the first data
 625                                          * byte in the packet, which is
 626                                          * the first data byte in the
 627                                          * record.
 628                                          */
 629                                         pkt->id_offset = pkt->cd_offset;
 630                                         pkt->sd_offset = state->offset;
 631                                 }
 632
 633                                 if (n == 0)
 634                                         continue;
 635
 636                                 g_assert(num_bytes_to_skip < n);
 637                                 while (num_bytes_to_skip) {
 638                                         if (file_getc(fh) == EOF)
 639                                                 goto done;
 640                                         state->offset++;
 641                                         num_bytes_to_skip--;
 642                                         n--;
 643                                 }
 644                                 num_written = process_data(state, fh, pkt, n,
 645                                     pd, err, err_info, pid);
 646
 647                                 if (num_written < 0) {
 648                                         return FALSE;
 649                                 }
 650                                 else if (num_written > 0) {
 651                                         *num_bytes = num_written;
 652                                         *direction = pkt->dir;
 653                                         return TRUE;
 654                                 }
 655                                 /* if 0 bytes written, keep looping */
 656                                 break;
 657
 658                         case PPPD_SEND_DELIM:
 659                         case PPPD_RECV_DELIM:
 660                                 /* What can we do? */
 661                                 break;
 662
 663                         case PPPD_RESET_TIME:
 664                                 wtap_file_read_unknown_bytes(&time_long, sizeof(guint32), fh, err, err_info);
 665                                 state->offset += sizeof(guint32);
 666                                 state->timestamp = pntohl(&time_long);
 667                                 state->tenths = 0;
 668                                 break;
 669
 670                         case PPPD_TIME_STEP_LONG:
 671                                 wtap_file_read_unknown_bytes(&time_long, sizeof(guint32), fh, err, err_info);
 672                                 state->offset += sizeof(guint32);
 673                                 state->tenths += pntohl(&time_long);
 674
 675                                 if (state->tenths >= 10) {
 676                                         state->timestamp += state->tenths / 10;
 677                                         state->tenths = state->tenths % 10;
 678                                 }
 679
 680                                 break;
 681
 682                         case PPPD_TIME_STEP_SHORT:
 683                                 wtap_file_read_unknown_bytes(&time_short, sizeof(guint8), fh, err, err_info);
 684                                 state->offset += sizeof(guint8);
 685                                 state->tenths += time_short;
 686
 687                                 if (state->tenths >= 10) {
 688                                         state->timestamp += state->tenths / 10;
 689                                         state->tenths = state->tenths % 10;
 690                                 }
 691
 692                                 break;
 693
 694                         default:
 695                                 /* XXX - bad file */
 696                                 *err = WTAP_ERR_BAD_FILE;
 697                                 *err_info = g_strdup_printf("pppdump: bad ID byte 0x%02x", id);
 698                                 return FALSE;
 699                 }
 700
 701         }
 702
 703 done:
 704         *err = file_error(fh, err_info);
 705         if (*err == 0) {
 706                 if (state->offset != start_offset) {
 707                         /*
 708                          * We read at least one byte, so we were working
 709                          * on a record; an EOF means that record was
 710                          * cut short.
 711                          */
 712                         *err = WTAP_ERR_SHORT_READ;
 713                 }
 714         }
 715         return FALSE;
 716 }
 717
 718
 719
 720 /* Used to read packets in random-access fashion */
 721 static gboolean
 722 pppdump_seek_read(wtap *wth,
 723                  gint64 seek_off,
 724                  struct wtap_pkthdr *phdr,
 725                  Buffer *buf,
 726                  int len,
 727                  int *err,
 728                  gchar **err_info)
 729 {
 730         int             num_bytes;
 731         guint8          *pd;
 732         direction_enum  direction;
 733         pppdump_t       *state;
 734         pkt_id          *pid;
 735         gint64          num_bytes_to_skip;
 736
 737         state = (pppdump_t *)wth->priv;
 738
 739         pid = (pkt_id *)g_ptr_array_index(state->pids, seek_off);
 740         if (!pid) {
 741                 *err = WTAP_ERR_BAD_FILE;       /* XXX - better error? */
 742                 *err_info = g_strdup("pppdump: PID not found for record");
 743                 return FALSE;
 744         }
 745
 746         if (file_seek(wth->random_fh, pid->offset, SEEK_SET, err) == -1)
 747                 return FALSE;
 748
 749         init_state(state->seek_state);
 750         state->seek_state->offset = pid->offset;
 751
 752         buffer_assure_space(buf, PPPD_BUF_SIZE);
 753         pd = buffer_start_ptr(buf);
 754
 755         /*
 756          * We'll start reading at the first record containing data from
 757          * this packet; however, that doesn't mean "collate()" will
 758          * stop only when we've read that packet, as there might be
 759          * data for packets going in the other direction as well, and
 760          * we might finish processing one of those packets before we
 761          * finish processing the packet we're reading.
 762          *
 763          * Therefore, we keep reading until we get a packet that's
 764          * going in the direction we want.
 765          */
 766         num_bytes_to_skip = pid->num_bytes_to_skip;
 767         do {
 768                 if (!collate(state->seek_state, wth->random_fh, err, err_info,
 769                     pd, &num_bytes, &direction, NULL, num_bytes_to_skip))
 770                         return FALSE;
 771                 num_bytes_to_skip = 0;
 772         } while (direction != pid->dir);
 773
 774         if (len != num_bytes) {
 775                 *err = WTAP_ERR_BAD_FILE;       /* XXX - better error? */
 776                 *err_info = g_strdup_printf("pppdump: requested length %d doesn't match record length %d",
 777                     len, num_bytes);
 778                 return FALSE;
 779         }
 780
 781         pppdump_set_phdr(phdr, num_bytes, pid->dir);
 782
 783         return TRUE;
 784 }
 785
 786 static void
 787 pppdump_close(wtap *wth)
 788 {
 789         pppdump_t       *state;
 790
 791         state = (pppdump_t *)wth->priv;
 792
 793         if (state->seek_state) { /* should always be TRUE */
 794                 g_free(state->seek_state);
 795         }
 796
 797         if (state->pids) {
 798                 unsigned int i;
 799                 for (i = 0; i < g_ptr_array_len(state->pids); i++) {
 800                         g_free(g_ptr_array_index(state->pids, i));
 801                 }
 802                 g_ptr_array_free(state->pids, TRUE);
 803         }
 804 }