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 *err, gchar **err_info);
 104
 105 /*
 106  * Information saved about a packet, during the initial sequential pass
 107  * through the file, to allow us to later re-read it when randomly
 108  * reading packets.
 109  *
 110  * "offset" is the offset in the file of the first data chunk containing data
 111  * from that packet; note that it may also contain data from previous
 112  * packets.
 113  *
 114  * "num_bytes_to_skip" is the number of bytes from previous packets in that
 115  * first data chunk.
 116  *
 117  * "dir" is the direction of the packet.
 118  */
 119 typedef struct {
 120         gint64          offset;
 121         gint64          num_bytes_to_skip;
 122         direction_enum  dir;
 123 } pkt_id;
 124
 125 /*
 126  * Information about a packet currently being processed.  There is one of
 127  * these for the sent packet being processed and one of these for the
 128  * received packet being processed, as we could be in the middle of
 129  * processing both a received packet and a sent packet.
 130  *
 131  * "dir" is the direction of the packet.
 132  *
 133  * "cnt" is the number of bytes of packet data we've accumulated.
 134  *
 135  * "esc" is TRUE if the next byte we see is escaped (and thus must be XORed
 136  * with 0x20 before saving it), FALSE otherwise.
 137  *
 138  * "buf" is a buffer containing the packet data we've accumulated.
 139  *
 140  * "id_offset" is the offset in the file of the first data chunk
 141  * containing data from the packet we're processing.
 142  *
 143  * "sd_offset" is the offset in the file of the first data byte from
 144  * the packet we're processing - which isn't necessarily right after
 145  * the header of the first data chunk, as we may already have assembled
 146  * packets from that chunk.
 147  *
 148  * "cd_offset" is the offset in the file of the current data chunk we're
 149  * processing.
 150  */
 151 typedef struct {
 152         direction_enum  dir;
 153         int             cnt;
 154         gboolean        esc;
 155         guint8          buf[PPPD_BUF_SIZE];
 156         gint64          id_offset;
 157         gint64          sd_offset;
 158         gint64          cd_offset;
 159 } pkt_t;
 160
 161 /*
 162  * This keeps state used while processing records.
 163  *
 164  * "timestamp" is the seconds portion of the current time stamp value,
 165  * as updated from PPPD_RESET_TIME, PPPD_TIME_STEP_LONG, and
 166  * PPPD_TIME_STEP_SHORT records.  "tenths" is the tenths-of-seconds
 167  * portion.
 168  *
 169  * "spkt" and "rpkt" are "pkt_t" structures for the sent and received
 170  * packets we're currently working on.
 171  *
 172  * "offset" is the current offset in the file.
 173  *
 174  * "num_bytes" and "pkt" are information saved when we finish accumulating
 175  * the data for a packet, if the data chunk we're working on still has more
 176  * data in it:
 177  *
 178  *      "num_bytes" is the number of bytes of additional data remaining
 179  *      in the chunk after we've finished accumulating the data for the
 180  *      packet.
 181  *
 182  *      "pkt" is the "pkt_t" for the type of packet the data chunk is for
 183  *      (sent or received packet).
 184  *
 185  * "seek_state" is another state structure used while processing records
 186  * when doing a seek-and-read.  (That structure doesn't itself have a
 187  * "seek_state" structure.)
 188  *
 189  * "pids" is a GPtrArray of pointers to "pkt_id" structures for all the
 190  * packets we've seen during the initial sequential pass, to allow us to
 191  * later retrieve them with random accesses.
 192  *
 193  * "pkt_cnt" is the number of packets we've seen up to this point in the
 194  * sequential pass.
 195  */
 196 typedef struct _pppdump_t {
 197         time_t                  timestamp;
 198         guint                   tenths;
 199         pkt_t                   spkt;
 200         pkt_t                   rpkt;
 201         gint64                  offset;
 202         int                     num_bytes;
 203         pkt_t                   *pkt;
 204         struct _pppdump_t       *seek_state;
 205         GPtrArray               *pids;
 206         guint                   pkt_cnt;
 207 } pppdump_t;
 208
 209 static int
 210 process_data(pppdump_t *state, FILE_T fh, pkt_t *pkt, int n, guint8 *pd,
 211     int *err, gchar **err_info, pkt_id *pid);
 212
 213 static gboolean
 214 collate(pppdump_t*, FILE_T fh, int *err, gchar **err_info, guint8 *pd,
 215                 int *num_bytes, direction_enum *direction, pkt_id *pid,
 216                 gint64 num_bytes_to_skip);
 217
 218 static void
 219 pppdump_close(wtap *wth);
 220
 221 static void
 222 init_state(pppdump_t *state)
 223 {
 224
 225         state->num_bytes = 0;
 226         state->pkt = NULL;
 227
 228         state->spkt.dir = DIRECTION_SENT;
 229         state->spkt.cnt = 0;
 230         state->spkt.esc = FALSE;
 231         state->spkt.id_offset = 0;
 232         state->spkt.sd_offset = 0;
 233         state->spkt.cd_offset = 0;
 234
 235         state->rpkt.dir = DIRECTION_RECV;
 236         state->rpkt.cnt = 0;
 237         state->rpkt.esc = FALSE;
 238         state->rpkt.id_offset = 0;
 239         state->rpkt.sd_offset = 0;
 240         state->rpkt.cd_offset = 0;
 241
 242         state->seek_state = NULL;
 243         state->offset = 0x100000; /* to detect errors during development */
 244 }
 245
 246
 247 int
 248 pppdump_open(wtap *wth, int *err, gchar **err_info)
 249 {
 250         guint8          buffer[6];      /* Looking for: 0x07 t3 t2 t1 t0 ID */
 251         int             bytes_read;
 252         pppdump_t       *state;
 253
 254         /* There is no file header, only packet records. Fortunately for us,
 255         * timestamp records are separated from packet records, so we should
 256         * find an "initial time stamp" (i.e., a "reset time" record, or
 257         * record type 0x07) at the beginning of the file. We'll check for
 258         * that, plus a valid record following the 0x07 and the four bytes
 259         * representing the timestamp.
 260         */
 261
 262         bytes_read = file_read(buffer, sizeof(buffer), wth->fh);
 263         if (bytes_read != (int) sizeof(buffer)) {
 264                 *err = file_error(wth->fh, err_info);
 265                 if (*err != 0 && *err != WTAP_ERR_SHORT_READ)
 266                         return -1;
 267                 return 0;
 268         }
 269
 270         if (buffer[0] == PPPD_RESET_TIME &&
 271                         (buffer[5] == PPPD_SENT_DATA ||
 272                          buffer[5] == PPPD_RECV_DATA ||
 273                          buffer[5] == PPPD_TIME_STEP_LONG ||
 274                          buffer[5] == PPPD_TIME_STEP_SHORT ||
 275                          buffer[5] == PPPD_RESET_TIME)) {
 276
 277                 goto my_file_type;
 278         }
 279         else {
 280                 return 0;
 281         }
 282
 283   my_file_type:
 284
 285         if (file_seek(wth->fh, 5, SEEK_SET, err) == -1)
 286                 return -1;
 287
 288         state = (pppdump_t *)g_malloc(sizeof(pppdump_t));
 289         wth->priv = (void *)state;
 290         state->timestamp = pntoh32(&buffer[1]);
 291         state->tenths = 0;
 292
 293         init_state(state);
 294
 295         state->offset = 5;
 296         wth->file_encap = WTAP_ENCAP_PPP_WITH_PHDR;
 297         wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_PPPDUMP;
 298
 299         wth->snapshot_length = PPPD_BUF_SIZE; /* just guessing */
 300         wth->subtype_read = pppdump_read;
 301         wth->subtype_seek_read = pppdump_seek_read;
 302         wth->subtype_close = pppdump_close;
 303         wth->tsprecision = WTAP_FILE_TSPREC_DSEC;
 304
 305         state->seek_state = g_new(pppdump_t,1);
 306
 307         /* If we have a random stream open, we're going to be reading
 308            the file randomly; set up a GPtrArray of pointers to
 309            information about how to retrieve the data for each packet. */
 310         if (wth->random_fh != NULL)
 311                 state->pids = g_ptr_array_new();
 312         else
 313                 state->pids = NULL;
 314         state->pkt_cnt = 0;
 315
 316         return 1;
 317 }
 318
 319 /* Set part of the struct wtap_pkthdr. */
 320 static void
 321 pppdump_set_phdr(struct wtap_pkthdr *phdr, int num_bytes,
 322     direction_enum direction)
 323 {
 324         phdr->len = num_bytes;
 325         phdr->caplen = num_bytes;
 326         phdr->pkt_encap = WTAP_ENCAP_PPP_WITH_PHDR;
 327
 328         phdr->pseudo_header.p2p.sent = (direction == DIRECTION_SENT ? TRUE : FALSE);
 329 }
 330
 331 /* Find the next packet and parse it; called from wtap_read(). */
 332 static gboolean
 333 pppdump_read(wtap *wth, int *err, gchar **err_info, gint64 *data_offset)
 334 {
 335         int             num_bytes;
 336         direction_enum  direction;
 337         guint8          *buf;
 338         pppdump_t       *state;
 339         pkt_id          *pid;
 340
 341         state = (pppdump_t *)wth->priv;
 342
 343         /* If we have a random stream open, allocate a structure to hold
 344            the information needed to read this packet's data again. */
 345         if (wth->random_fh != NULL) {
 346                 pid = g_new(pkt_id, 1);
 347                 if (!pid) {
 348                         *err = errno;   /* assume a malloc failed and set "errno" */
 349                         return FALSE;
 350                 }
 351                 pid->offset = 0;
 352         } else
 353                 pid = NULL;     /* sequential only */
 354
 355         buffer_assure_space(wth->frame_buffer, PPPD_BUF_SIZE);
 356         buf = buffer_start_ptr(wth->frame_buffer);
 357
 358         if (!collate(state, wth->fh, err, err_info, buf, &num_bytes, &direction,
 359             pid, 0)) {
 360                 if (pid != NULL)
 361                         g_free(pid);
 362                 return FALSE;
 363         }
 364
 365         if (pid != NULL)
 366                 pid->dir = direction;
 367
 368         if (pid != NULL)
 369                 g_ptr_array_add(state->pids, pid);
 370         /* The user's data_offset is not really an offset, but a packet number. */
 371         *data_offset = state->pkt_cnt;
 372         state->pkt_cnt++;
 373
 374         wth->phdr.presence_flags = WTAP_HAS_TS;
 375         wth->phdr.ts.secs       = state->timestamp;
 376         wth->phdr.ts.nsecs      = state->tenths * 100000000;
 377         pppdump_set_phdr(&wth->phdr, num_bytes, direction);
 378
 379         return TRUE;
 380 }
 381
 382 /* Returns number of bytes copied for record, -1 if failure.
 383  *
 384  * This is modeled after pppdump.c, the utility to parse pppd log files; it
 385  * comes with the ppp distribution.
 386  */
 387 static int
 388 process_data(pppdump_t *state, FILE_T fh, pkt_t *pkt, int n, guint8 *pd,
 389     int *err, gchar **err_info, pkt_id *pid)
 390 {
 391         int     c;
 392         int     num_bytes = n;
 393         int     num_written;
 394
 395         for (; num_bytes > 0; --num_bytes) {
 396                 c = file_getc(fh);
 397                 if (c == EOF) {
 398                         *err = file_error(fh, err_info);
 399                         if (*err == 0) {
 400                                 *err = WTAP_ERR_SHORT_READ;
 401                         }
 402                         return -1;
 403                 }
 404                 state->offset++;
 405                 switch (c) {
 406                         case 0x7e:
 407                                 /*
 408                                  * Flag Sequence for RFC 1662 HDLC-like
 409                                  * framing.
 410                                  *
 411                                  * As this is a raw trace of octets going
 412                                  * over the wire, and that might include
 413                                  * the login sequence, there is no
 414                                  * guarantee that *only* PPP traffic
 415                                  * appears in this file, so there is no
 416                                  * guarantee that the first 0x7e we see is
 417                                  * a start flag sequence, and therefore we
 418                                  * cannot safely ignore all characters up
 419                                  * to the first 0x7e, and therefore we
 420                                  * might end up with some bogus PPP
 421                                  * packets.
 422                                  */
 423                                 if (pkt->cnt > 0) {
 424                                         /*
 425                                          * We've seen stuff before this,
 426                                          * so this is the end of a frame.
 427                                          * Make a frame out of that stuff.
 428                                          */
 429                                         pkt->esc = FALSE;
 430
 431                                         num_written = pkt->cnt;
 432                                         pkt->cnt = 0;
 433                                         if (num_written <= 0) {
 434                                                 return 0;
 435                                         }
 436
 437                                         if (num_written > PPPD_BUF_SIZE) {
 438                                                 *err = WTAP_ERR_UNC_OVERFLOW;
 439                                                 return -1;
 440                                         }
 441
 442                                         memcpy(pd, pkt->buf, num_written);
 443
 444                                         /*
 445                                          * Remember the offset of the
 446                                          * first record containing data
 447                                          * for this packet, and how far
 448                                          * into that record to skip to
 449                                          * get to the beginning of the
 450                                          * data for this packet; the number
 451                                          * of bytes to skip into that record
 452                                          * is the file offset of the first
 453                                          * byte of this packet minus the
 454                                          * file offset of the first byte of
 455                                          * this record, minus 3 bytes for the
 456                                          * header of this record (which, if
 457                                          * we re-read this record, we will
 458                                          * process, not skip).
 459                                          */
 460                                         if (pid) {
 461                                                 pid->offset = pkt->id_offset;
 462                                                 pid->num_bytes_to_skip =
 463                                                     pkt->sd_offset - pkt->id_offset - 3;
 464                                                 g_assert(pid->num_bytes_to_skip >= 0);
 465                                         }
 466
 467                                         num_bytes--;
 468                                         if (num_bytes > 0) {
 469                                                 /*
 470                                                  * There's more data in this
 471                                                  * record.
 472                                                  * Set the initial data offset
 473                                                  * for the next packet.
 474                                                  */
 475                                                 pkt->id_offset = pkt->cd_offset;
 476                                                 pkt->sd_offset = state->offset;
 477                                         } else {
 478                                                 /*
 479                                                  * There is no more data in
 480                                                  * this record.
 481                                                  * Thus, we don't have the
 482                                                  * initial data offset for
 483                                                  * the next packet.
 484                                                  */
 485                                                 pkt->id_offset = 0;
 486                                                 pkt->sd_offset = 0;
 487                                         }
 488                                         state->num_bytes = num_bytes;
 489                                         state->pkt = pkt;
 490                                         return num_written;
 491                                 }
 492                                 break;
 493
 494                         case 0x7d:
 495                                 /*
 496                                  * Control Escape octet for octet-stuffed
 497                                  * RFC 1662 HDLC-like framing.
 498                                  */
 499                                 if (!pkt->esc) {
 500                                         /*
 501                                          * Control Escape not preceded by
 502                                          * Control Escape; discard it
 503                                          * but XOR the next octet with
 504                                          * 0x20.
 505                                          */
 506                                         pkt->esc = TRUE;
 507                                         break;
 508                                 }
 509                                 /*
 510                                  * Control Escape preceded by Control Escape;
 511                                  * treat it as an ordinary character,
 512                                  * by falling through.
 513                                  */
 514
 515                         default:
 516                                 if (pkt->esc) {
 517                                         /*
 518                                          * This character was preceded by
 519                                          * Control Escape, so XOR it with
 520                                          * 0x20, as per RFC 1662's octet-
 521                                          * stuffed framing, and clear
 522                                          * the flag saying that the
 523                                          * character should be escaped.
 524                                          */
 525                                         c ^= 0x20;
 526                                         pkt->esc = FALSE;
 527                                 }
 528
 529                                 if (pkt->cnt >= PPPD_BUF_SIZE) {
 530                                         *err = WTAP_ERR_UNC_OVERFLOW;
 531                                         return -1;
 532                                 }
 533                                 pkt->buf[pkt->cnt++] = c;
 534                                 break;
 535                 }
 536         }
 537
 538         /* we could have run out of bytes to read */
 539         return 0;
 540 }
 541
 542 /* Returns TRUE if packet data copied, FALSE if error occurred or EOF (no more records). */
 543 static gboolean
 544 collate(pppdump_t* state, FILE_T fh, int *err, gchar **err_info, guint8 *pd,
 545                 int *num_bytes, direction_enum *direction, pkt_id *pid,
 546                 gint64 num_bytes_to_skip)
 547 {
 548         int             id;
 549         pkt_t           *pkt = NULL;
 550         int             byte0, byte1;
 551         int             n, num_written = 0;
 552         gint64          start_offset;
 553         guint32         time_long;
 554         guint8          time_short;
 555
 556         /*
 557          * Process any data left over in the current record when doing
 558          * sequential processing.
 559          */
 560         if (state->num_bytes > 0) {
 561                 g_assert(num_bytes_to_skip == 0);
 562                 pkt = state->pkt;
 563                 num_written = process_data(state, fh, pkt, state->num_bytes,
 564                     pd, err, err_info, pid);
 565
 566                 if (num_written < 0) {
 567                         return FALSE;
 568                 }
 569                 else if (num_written > 0) {
 570                         *num_bytes = num_written;
 571                         *direction = pkt->dir;
 572                         return TRUE;
 573                 }
 574                 /* if 0 bytes written, keep processing */
 575         } else {
 576                 /*
 577                  * We didn't have any data left over, so the packet will
 578                  * start at the beginning of a record.
 579                  */
 580                 if (pid)
 581                         pid->num_bytes_to_skip = 0;
 582         }
 583
 584         /*
 585          * That didn't get all the data for this packet, so process
 586          * subsequent records.
 587          */
 588         start_offset = state->offset;
 589         while ((id = file_getc(fh)) != EOF) {
 590                 state->offset++;
 591                 switch (id) {
 592                         case PPPD_SENT_DATA:
 593                         case PPPD_RECV_DATA:
 594                                 pkt = id == PPPD_SENT_DATA ? &state->spkt : &state->rpkt;
 595
 596                                 /*
 597                                  * Save the offset of the beginning of
 598                                  * the current record.
 599                                  */
 600                                 pkt->cd_offset = state->offset - 1;
 601
 602                                 /*
 603                                  * Get the length of the record.
 604                                  */
 605                                 byte0 = file_getc(fh);
 606                                 if (byte0 == EOF)
 607                                         goto done;
 608                                 state->offset++;
 609                                 byte1 = file_getc(fh);
 610                                 if (byte1 == EOF)
 611                                         goto done;
 612                                 state->offset++;
 613                                 n = (byte0 << 8) | byte1;
 614
 615                                 if (pkt->id_offset == 0) {
 616                                         /*
 617                                          * We don't have the initial data
 618                                          * offset for this packet, which
 619                                          * means this is the first
 620                                          * data record for that packet.
 621                                          * Save the offset of the
 622                                          * beginning of that record and
 623                                          * the offset of the first data
 624                                          * byte in the packet, which is
 625                                          * the first data byte in the
 626                                          * record.
 627                                          */
 628                                         pkt->id_offset = pkt->cd_offset;
 629                                         pkt->sd_offset = state->offset;
 630                                 }
 631
 632                                 if (n == 0)
 633                                         continue;
 634
 635                                 g_assert(num_bytes_to_skip < n);
 636                                 while (num_bytes_to_skip) {
 637                                         if (file_getc(fh) == EOF)
 638                                                 goto done;
 639                                         state->offset++;
 640                                         num_bytes_to_skip--;
 641                                         n--;
 642                                 }
 643                                 num_written = process_data(state, fh, pkt, n,
 644                                     pd, err, err_info, pid);
 645
 646                                 if (num_written < 0) {
 647                                         return FALSE;
 648                                 }
 649                                 else if (num_written > 0) {
 650                                         *num_bytes = num_written;
 651                                         *direction = pkt->dir;
 652                                         return TRUE;
 653                                 }
 654                                 /* if 0 bytes written, keep looping */
 655                                 break;
 656
 657                         case PPPD_SEND_DELIM:
 658                         case PPPD_RECV_DELIM:
 659                                 /* What can we do? */
 660                                 break;
 661
 662                         case PPPD_RESET_TIME:
 663                                 wtap_file_read_unknown_bytes(&time_long, sizeof(guint32), fh, err, err_info);
 664                                 state->offset += sizeof(guint32);
 665                                 state->timestamp = pntoh32(&time_long);
 666                                 state->tenths = 0;
 667                                 break;
 668
 669                         case PPPD_TIME_STEP_LONG:
 670                                 wtap_file_read_unknown_bytes(&time_long, sizeof(guint32), fh, err, err_info);
 671                                 state->offset += sizeof(guint32);
 672                                 state->tenths += pntoh32(&time_long);
 673
 674                                 if (state->tenths >= 10) {
 675                                         state->timestamp += state->tenths / 10;
 676                                         state->tenths = state->tenths % 10;
 677                                 }
 678
 679                                 break;
 680
 681                         case PPPD_TIME_STEP_SHORT:
 682                                 wtap_file_read_unknown_bytes(&time_short, sizeof(guint8), fh, err, err_info);
 683                                 state->offset += sizeof(guint8);
 684                                 state->tenths += time_short;
 685
 686                                 if (state->tenths >= 10) {
 687                                         state->timestamp += state->tenths / 10;
 688                                         state->tenths = state->tenths % 10;
 689                                 }
 690
 691                                 break;
 692
 693                         default:
 694                                 /* XXX - bad file */
 695                                 *err = WTAP_ERR_BAD_FILE;
 696                                 *err_info = g_strdup_printf("pppdump: bad ID byte 0x%02x", id);
 697                                 return FALSE;
 698                 }
 699
 700         }
 701
 702 done:
 703         *err = file_error(fh, err_info);
 704         if (*err == 0) {
 705                 if (state->offset != start_offset) {
 706                         /*
 707                          * We read at least one byte, so we were working
 708                          * on a record; an EOF means that record was
 709                          * cut short.
 710                          */
 711                         *err = WTAP_ERR_SHORT_READ;
 712                 }
 713         }
 714         return FALSE;
 715 }
 716
 717
 718
 719 /* Used to read packets in random-access fashion */
 720 static gboolean
 721 pppdump_seek_read(wtap *wth,
 722                  gint64 seek_off,
 723                  struct wtap_pkthdr *phdr,
 724                  Buffer *buf,
 725                  int *err,
 726                  gchar **err_info)
 727 {
 728         int             num_bytes;
 729         guint8          *pd;
 730         direction_enum  direction;
 731         pppdump_t       *state;
 732         pkt_id          *pid;
 733         gint64          num_bytes_to_skip;
 734
 735         state = (pppdump_t *)wth->priv;
 736
 737         pid = (pkt_id *)g_ptr_array_index(state->pids, seek_off);
 738         if (!pid) {
 739                 *err = WTAP_ERR_BAD_FILE;       /* XXX - better error? */
 740                 *err_info = g_strdup("pppdump: PID not found for record");
 741                 return FALSE;
 742         }
 743
 744         if (file_seek(wth->random_fh, pid->offset, SEEK_SET, err) == -1)
 745                 return FALSE;
 746
 747         init_state(state->seek_state);
 748         state->seek_state->offset = pid->offset;
 749
 750         buffer_assure_space(buf, PPPD_BUF_SIZE);
 751         pd = buffer_start_ptr(buf);
 752
 753         /*
 754          * We'll start reading at the first record containing data from
 755          * this packet; however, that doesn't mean "collate()" will
 756          * stop only when we've read that packet, as there might be
 757          * data for packets going in the other direction as well, and
 758          * we might finish processing one of those packets before we
 759          * finish processing the packet we're reading.
 760          *
 761          * Therefore, we keep reading until we get a packet that's
 762          * going in the direction we want.
 763          */
 764         num_bytes_to_skip = pid->num_bytes_to_skip;
 765         do {
 766                 if (!collate(state->seek_state, wth->random_fh, err, err_info,
 767                     pd, &num_bytes, &direction, NULL, num_bytes_to_skip))
 768                         return FALSE;
 769                 num_bytes_to_skip = 0;
 770         } while (direction != pid->dir);
 771
 772         pppdump_set_phdr(phdr, num_bytes, pid->dir);
 773
 774         return TRUE;
 775 }
 776
 777 static void
 778 pppdump_close(wtap *wth)
 779 {
 780         pppdump_t       *state;
 781
 782         state = (pppdump_t *)wth->priv;
 783
 784         if (state->seek_state) { /* should always be TRUE */
 785                 g_free(state->seek_state);
 786         }
 787
 788         if (state->pids) {
 789                 unsigned int i;
 790                 for (i = 0; i < g_ptr_array_len(state->pids); i++) {
 791                         g_free(g_ptr_array_index(state->pids, i));
 792                 }
 793                 g_ptr_array_free(state->pids, TRUE);
 794         }
 795 }