wiretap/stanag4607.c

   1 /* stanag4607.c
   2  *
   3  * STANAG 4607 file reading
   4  *
   5  * http://www.nato.int/structur/AC/224/standard/4607/4607e_JAS_ED3.pdf
   6  * That is now missing from that site, but is available on the Wayback
   7  * Machine:
   8  *
   9  * https://web.archive.org/web/20130223054955/http://www.nato.int/structur/AC/224/standard/4607/4607.htm
  10  *
  11  * https://nso.nato.int/nso/zPublic/ap/aedp-7(2).pdf
  12  *
  13  * SPDX-License-Identifier: GPL-2.0-or-later
  14  */
  15
  16 #include "config.h"
  17 #include "stanag4607.h"
  18
  19 #include "wtap-int.h"
  20 #include "file_wrappers.h"
  21 #include <wsutil/buffer.h>
  22
  23 typedef struct {
  24   time_t base_secs;
  25 } stanag4607_t;
  26
  27 #define PKT_HDR_SIZE  32 /* size of a packet header */
  28 #define SEG_HDR_SIZE  5  /* size of a segment header */
  29
  30 static int stanag4607_file_type_subtype = -1;
  31
  32 void register_stanag4607(void);
  33
  34 static bool is_valid_id(uint16_t version_id)
  35 {
  36 #define VERSION_21 0x3231
  37 #define VERSION_30 0x3330
  38   if ((version_id != VERSION_21) &&
  39       (version_id != VERSION_30))
  40      /* Not a stanag4607 file */
  41      return false;
  42   return true;
  43 }
  44
  45 static bool stanag4607_read_file(wtap *wth, FILE_T fh, wtap_rec *rec,
  46                                Buffer *buf, int *err, char **err_info)
  47 {
  48   stanag4607_t *stanag4607 = (stanag4607_t *)wth->priv;
  49   uint32_t millisecs, secs, nsecs;
  50   int64_t offset = 0;
  51   uint8_t stanag_pkt_hdr[PKT_HDR_SIZE+SEG_HDR_SIZE];
  52   uint32_t packet_size;
  53
  54   *err = 0;
  55
  56   /* Combined packet header and segment header */
  57   if (!wtap_read_bytes_or_eof(fh, stanag_pkt_hdr, sizeof stanag_pkt_hdr, err, err_info))
  58     return false;
  59   offset += sizeof stanag_pkt_hdr;
  60
  61   if (!is_valid_id(pntoh16(&stanag_pkt_hdr[0]))) {
  62     *err = WTAP_ERR_BAD_FILE;
  63     *err_info = g_strdup("Bad version number");
  64     return false;
  65   }
  66
  67   rec->rec_type = REC_TYPE_PACKET;
  68   rec->block = wtap_block_create(WTAP_BLOCK_PACKET);
  69
  70   /* The next 4 bytes are the packet length */
  71   packet_size = pntoh32(&stanag_pkt_hdr[2]);
  72   if (packet_size > WTAP_MAX_PACKET_SIZE_STANDARD) {
  73     /*
  74      * Probably a corrupt capture file; don't blow up trying
  75      * to allocate space for an immensely-large packet.
  76      */
  77     *err = WTAP_ERR_BAD_FILE;
  78     *err_info = ws_strdup_printf("stanag4607: File has %" PRIu32 "d-byte packet, "
  79       "bigger than maximum of %u", packet_size, WTAP_MAX_PACKET_SIZE_STANDARD);
  80     return false;
  81   }
  82   if (packet_size < PKT_HDR_SIZE+SEG_HDR_SIZE) {
  83     /*
  84      * Probably a corrupt capture file; don't, for example, loop
  85      * infinitely if the size is zero.
  86      */
  87     *err = WTAP_ERR_BAD_FILE;
  88     *err_info = ws_strdup_printf("stanag4607: File has %" PRIu32 "d-byte packet, "
  89       "smaller than minimum of %u", packet_size, PKT_HDR_SIZE+SEG_HDR_SIZE);
  90     return false;
  91   }
  92   rec->rec_header.packet_header.caplen = packet_size;
  93   rec->rec_header.packet_header.len = packet_size;
  94
  95   /* Sadly, the header doesn't contain times; but some segments do */
  96   /* So, get the segment header, which is just past the 32-byte header. */
  97   rec->presence_flags = WTAP_HAS_TS;
  98
  99   /* If no time specified, it's the last baseline time */
 100   rec->ts.secs = stanag4607->base_secs;
 101   rec->ts.nsecs = 0;
 102   millisecs = 0;
 103
 104 #define MISSION_SEGMENT 1
 105 #define DWELL_SEGMENT 2
 106 #define JOB_DEFINITION_SEGMENT 5
 107 #define PLATFORM_LOCATION_SEGMENT 13
 108   if (MISSION_SEGMENT == stanag_pkt_hdr[32]) {
 109     uint8_t mseg[39];
 110     struct tm tm;
 111
 112     if (!wtap_read_bytes(fh, &mseg, sizeof mseg, err, err_info))
 113       return false;
 114     offset += sizeof mseg;
 115
 116     tm.tm_year = pntoh16(&mseg[35]) - 1900;
 117     tm.tm_mon = mseg[37] - 1;
 118     tm.tm_mday = mseg[38];
 119     tm.tm_hour = 0;
 120     tm.tm_min = 0;
 121     tm.tm_sec = 0;
 122     tm.tm_isdst = -1;
 123     stanag4607->base_secs = mktime(&tm);
 124     rec->ts.secs = stanag4607->base_secs;
 125   }
 126   else if (PLATFORM_LOCATION_SEGMENT == stanag_pkt_hdr[32]) {
 127     if (!wtap_read_bytes(fh, &millisecs, sizeof millisecs, err, err_info))
 128       return false;
 129     offset += sizeof millisecs;
 130     millisecs = g_ntohl(millisecs);
 131   }
 132   else if (DWELL_SEGMENT == stanag_pkt_hdr[32]) {
 133     uint8_t dseg[19];
 134     if (!wtap_read_bytes(fh, &dseg, sizeof dseg, err, err_info))
 135       return false;
 136     offset += sizeof dseg;
 137     millisecs = pntoh32(&dseg[15]);
 138   }
 139   if (0 != millisecs) {
 140     secs = millisecs/1000;
 141     nsecs = (millisecs - 1000 * secs) * 1000000;
 142     rec->ts.secs = stanag4607->base_secs + secs;
 143     rec->ts.nsecs = nsecs;
 144   }
 145
 146   /* wind back to the start of the packet ... */
 147   if (file_seek(fh, - offset, SEEK_CUR, err) == -1)
 148     return false;
 149
 150   return wtap_read_packet_bytes(fh, buf, packet_size, err, err_info);
 151 }
 152
 153 static bool stanag4607_read(wtap *wth, wtap_rec *rec, Buffer *buf,
 154                                 int *err, char **err_info, int64_t *data_offset)
 155 {
 156   *data_offset = file_tell(wth->fh);
 157
 158   return stanag4607_read_file(wth, wth->fh, rec, buf, err, err_info);
 159 }
 160
 161 static bool stanag4607_seek_read(wtap *wth, int64_t seek_off,
 162                                wtap_rec *rec,
 163                                Buffer *buf, int *err, char **err_info)
 164 {
 165   if (file_seek(wth->random_fh, seek_off, SEEK_SET, err) == -1)
 166     return false;
 167
 168   return stanag4607_read_file(wth, wth->random_fh, rec, buf, err, err_info);
 169 }
 170
 171 wtap_open_return_val stanag4607_open(wtap *wth, int *err, char **err_info)
 172 {
 173   uint16_t version_id;
 174   stanag4607_t *stanag4607;
 175
 176   if (!wtap_read_bytes(wth->fh, &version_id, sizeof version_id, err, err_info))
 177     return (*err != WTAP_ERR_SHORT_READ) ? WTAP_OPEN_ERROR : WTAP_OPEN_NOT_MINE;
 178
 179   if (!is_valid_id(GUINT16_TO_BE(version_id)))
 180      /* Not a stanag4607 file */
 181      return WTAP_OPEN_NOT_MINE;
 182
 183   /* seek back to the start of the file  */
 184   if (file_seek(wth->fh, 0, SEEK_SET, err) == -1)
 185     return WTAP_OPEN_ERROR;
 186
 187   wth->file_type_subtype = stanag4607_file_type_subtype;
 188   wth->file_encap = WTAP_ENCAP_STANAG_4607;
 189   wth->snapshot_length = 0; /* not known */
 190
 191   stanag4607 = g_new(stanag4607_t, 1);
 192   wth->priv = (void *)stanag4607;
 193   stanag4607->base_secs = 0; /* unknown as of yet */
 194
 195   wth->subtype_read = stanag4607_read;
 196   wth->subtype_seek_read = stanag4607_seek_read;
 197   wth->file_tsprec = WTAP_TSPREC_MSEC;
 198
 199   /*
 200    * Add an IDB; we don't know how many interfaces were
 201    * involved, so we just say one interface, about which
 202    * we only know the link-layer type, snapshot length,
 203    * and time stamp resolution.
 204    */
 205   wtap_add_generated_idb(wth);
 206
 207   return WTAP_OPEN_MINE;
 208 }
 209
 210 static const struct supported_block_type stanag4607_blocks_supported[] = {
 211   /*
 212    * We support packet blocks, with no comments or other options.
 213    */
 214   { WTAP_BLOCK_PACKET, MULTIPLE_BLOCKS_SUPPORTED, NO_OPTIONS_SUPPORTED }
 215 };
 216
 217 static const struct file_type_subtype_info stanag4607_info = {
 218   "STANAG 4607 Format", "stanag4607", NULL, NULL,
 219   false, BLOCKS_SUPPORTED(stanag4607_blocks_supported),
 220   NULL, NULL, NULL
 221 };
 222
 223 void register_stanag4607(void)
 224 {
 225   stanag4607_file_type_subtype = wtap_register_file_type_subtype(&stanag4607_info);
 226
 227   /*
 228    * Register name for backwards compatibility with the
 229    * wtap_filetypes table in Lua.
 230    */
 231   wtap_register_backwards_compatibility_lua_name("STANAG_4607",
 232                                                  stanag4607_file_type_subtype);
 233 }
 234
 235 /*
 236  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 237  *
 238  * Local Variables:
 239  * c-basic-offset: 2
 240  * tab-width: 8
 241  * indent-tabs-mode: nil
 242  * End:
 243  *
 244  * vi: set shiftwidth=2 tabstop=8 expandtab:
 245  * :indentSize=2:tabSize=8:noTabs=true:
 246  */