wiretap/i4btrace.c

   1 /* i4btrace.c
   2  *
   3  * Wiretap Library
   4  * Copyright (c) 1999 by Bert Driehuis <driehuis@playbeing.org>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 #include "config.h"
  22
  23 #include <stdlib.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include "wtap-int.h"
  27 #include "file_wrappers.h"
  28 #include "i4b_trace.h"
  29 #include "i4btrace.h"
  30
  31 typedef struct {
  32         gboolean byte_swapped;
  33 } i4btrace_t;
  34
  35 static gboolean i4btrace_read(wtap *wth, int *err, gchar **err_info,
  36     gint64 *data_offset);
  37 static gboolean i4btrace_seek_read(wtap *wth, gint64 seek_off,
  38     struct wtap_pkthdr *phdr, Buffer *buf, int *err, gchar **err_info);
  39 static int i4b_read_rec(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr,
  40     Buffer *buf, int *err, gchar **err_info);
  41
  42 /*
  43  * Test some fields in the header to see if they make sense.
  44  */
  45 #define I4B_HDR_IS_OK(hdr) \
  46         (!((unsigned int)hdr.length < 3 || (unsigned int)hdr.length > 16384 || \
  47             (unsigned int)hdr.unit > 4 || (unsigned int)hdr.type > 4 || \
  48             (unsigned int)hdr.dir > 2 || (unsigned int)hdr.trunc > 2048))
  49
  50 wtap_open_return_val i4btrace_open(wtap *wth, int *err, gchar **err_info)
  51 {
  52         i4b_trace_hdr_t hdr;
  53         gboolean byte_swapped = FALSE;
  54         i4btrace_t *i4btrace;
  55
  56         /* I4B trace files have no magic in the header... Sigh */
  57         if (!wtap_read_bytes(wth->fh, &hdr, sizeof(hdr), err, err_info)) {
  58                 if (*err != WTAP_ERR_SHORT_READ)
  59                         return WTAP_OPEN_ERROR;
  60                 return WTAP_OPEN_NOT_MINE;
  61         }
  62
  63         /* Silly heuristic... */
  64         if (!I4B_HDR_IS_OK(hdr)) {
  65                 /*
  66                  * OK, try byte-swapping the header fields.
  67                  */
  68                 hdr.length = GUINT32_SWAP_LE_BE(hdr.length);
  69                 hdr.unit = GUINT32_SWAP_LE_BE(hdr.unit);
  70                 hdr.type = GUINT32_SWAP_LE_BE(hdr.type);
  71                 hdr.dir = GUINT32_SWAP_LE_BE(hdr.dir);
  72                 hdr.trunc = GUINT32_SWAP_LE_BE(hdr.trunc);
  73                 if (!I4B_HDR_IS_OK(hdr)) {
  74                         /*
  75                          * It doesn't look valid in either byte order.
  76                          */
  77                         return WTAP_OPEN_NOT_MINE;
  78                 }
  79
  80                 /*
  81                  * It looks valid byte-swapped, so assume it's a
  82                  * trace written in the opposite byte order.
  83                  */
  84                 byte_swapped = TRUE;
  85         }
  86
  87         if (file_seek(wth->fh, 0, SEEK_SET, err) == -1)
  88                 return WTAP_OPEN_ERROR;
  89
  90         /* Get capture start time */
  91
  92         wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_I4BTRACE;
  93         i4btrace = (i4btrace_t *)g_malloc(sizeof(i4btrace_t));
  94         wth->priv = (void *)i4btrace;
  95         wth->subtype_read = i4btrace_read;
  96         wth->subtype_seek_read = i4btrace_seek_read;
  97         wth->snapshot_length = 0;       /* not known */
  98
  99         i4btrace->byte_swapped = byte_swapped;
 100
 101         wth->file_encap = WTAP_ENCAP_ISDN;
 102         wth->file_tsprec = WTAP_TSPREC_USEC;
 103
 104         return WTAP_OPEN_MINE;
 105 }
 106
 107 /* Read the next packet */
 108 static gboolean i4btrace_read(wtap *wth, int *err, gchar **err_info,
 109     gint64 *data_offset)
 110 {
 111         *data_offset = file_tell(wth->fh);
 112
 113         return i4b_read_rec(wth, wth->fh, &wth->phdr, wth->frame_buffer,
 114             err, err_info);
 115 }
 116
 117 static gboolean
 118 i4btrace_seek_read(wtap *wth, gint64 seek_off, struct wtap_pkthdr *phdr,
 119     Buffer *buf, int *err, gchar **err_info)
 120 {
 121         if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
 122                 return FALSE;
 123
 124         if (!i4b_read_rec(wth, wth->random_fh, phdr, buf, err, err_info)) {
 125                 /* Read error or EOF */
 126                 if (*err == 0) {
 127                         /* EOF means "short read" in random-access mode */
 128                         *err = WTAP_ERR_SHORT_READ;
 129                 }
 130                 return FALSE;
 131         }
 132         return TRUE;
 133 }
 134
 135 static gboolean
 136 i4b_read_rec(wtap *wth, FILE_T fh, struct wtap_pkthdr *phdr, Buffer *buf,
 137     int *err, gchar **err_info)
 138 {
 139         i4btrace_t *i4btrace = (i4btrace_t *)wth->priv;
 140         i4b_trace_hdr_t hdr;
 141         guint32 length;
 142
 143         if (!wtap_read_bytes_or_eof(fh, &hdr, sizeof hdr, err, err_info))
 144                 return FALSE;
 145
 146         if (i4btrace->byte_swapped) {
 147                 /*
 148                  * Byte-swap the header.
 149                  */
 150                 hdr.length = GUINT32_SWAP_LE_BE(hdr.length);
 151                 hdr.unit = GUINT32_SWAP_LE_BE(hdr.unit);
 152                 hdr.type = GUINT32_SWAP_LE_BE(hdr.type);
 153                 hdr.dir = GUINT32_SWAP_LE_BE(hdr.dir);
 154                 hdr.trunc = GUINT32_SWAP_LE_BE(hdr.trunc);
 155                 hdr.count = GUINT32_SWAP_LE_BE(hdr.count);
 156                 hdr.ts_sec = GUINT32_SWAP_LE_BE(hdr.ts_sec);
 157                 hdr.ts_usec = GUINT32_SWAP_LE_BE(hdr.ts_usec);
 158         }
 159
 160         if (hdr.length < sizeof(hdr)) {
 161                 *err = WTAP_ERR_BAD_FILE;       /* record length < header! */
 162                 *err_info = g_strdup_printf("i4btrace: record length %u < header length %lu",
 163                     hdr.length, (unsigned long)sizeof(hdr));
 164                 return FALSE;
 165         }
 166         length = hdr.length - (guint32)sizeof(hdr);
 167         if (length > WTAP_MAX_PACKET_SIZE) {
 168                 /*
 169                  * Probably a corrupt capture file; don't blow up trying
 170                  * to allocate space for an immensely-large packet.
 171                  */
 172                 *err = WTAP_ERR_BAD_FILE;
 173                 *err_info = g_strdup_printf("i4btrace: File has %u-byte packet, bigger than maximum of %u",
 174                     length, WTAP_MAX_PACKET_SIZE);
 175                 return FALSE;
 176         }
 177
 178         phdr->rec_type = REC_TYPE_PACKET;
 179         phdr->presence_flags = WTAP_HAS_TS;
 180
 181         phdr->len = length;
 182         phdr->caplen = length;
 183
 184         phdr->ts.secs = hdr.ts_sec;
 185         phdr->ts.nsecs = hdr.ts_usec * 1000;
 186
 187         switch (hdr.type) {
 188
 189         case TRC_CH_I:
 190                 /*
 191                  * XXX - what is it?  It's probably not WTAP_ENCAP_NULL,
 192                  * as that means it has a 4-byte AF_ type as the
 193                  * encapsulation header.
 194                  */
 195                 phdr->pkt_encap = WTAP_ENCAP_NULL;
 196                 break;
 197
 198         case TRC_CH_D:
 199                 /*
 200                  * D channel, so it's LAPD; set "p2p.sent".
 201                  */
 202                 phdr->pkt_encap = WTAP_ENCAP_ISDN;
 203                 phdr->pseudo_header.isdn.channel = 0;
 204                 break;
 205
 206         case TRC_CH_B1:
 207                 /*
 208                  * B channel 1.
 209                  */
 210                 phdr->pkt_encap = WTAP_ENCAP_ISDN;
 211                 phdr->pseudo_header.isdn.channel = 1;
 212                 break;
 213
 214         case TRC_CH_B2:
 215                 /*
 216                  * B channel 2.
 217                  */
 218                 phdr->pkt_encap = WTAP_ENCAP_ISDN;
 219                 phdr->pseudo_header.isdn.channel = 2;
 220                 break;
 221         }
 222
 223         phdr->pseudo_header.isdn.uton = (hdr.dir == FROM_TE);
 224
 225         /*
 226          * Read the packet data.
 227          */
 228         return wtap_read_packet_bytes(fh, buf, length, err, err_info);
 229 }
 230
 231 /*
 232  * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 233  *
 234  * Local variables:
 235  * c-basic-offset: 8
 236  * tab-width: 8
 237  * indent-tabs-mode: t
 238  * End:
 239  *
 240  * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 241  * :indentSize=8:tabSize=8:noTabs=false:
 242  */