epan/osi-utils.c

   1 /* osi-utils.c
   2  * Routines for ISO/OSI network and transport protocol packet disassembly
   3  * Main entrance point and common functions
   4  *
   5  * Laurent Deniel <laurent.deniel@free.fr>
   6  * Ralf Schneider <Ralf.Schneider@t-online.de>
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * SPDX-License-Identifier: GPL-2.0-or-later
  13  */
  14
  15 #include "config.h"
  16
  17 #include <stdio.h>
  18 #include <string.h>
  19 #include <glib.h>
  20
  21 #include "tvbuff.h"
  22 #include "osi-utils.h"
  23 #include "address.h"
  24 #include "address_types.h"
  25
  26 static void print_nsap_net_buf( const uint8_t *, int, char *, int);
  27 static void print_area_buf ( const uint8_t *, int, char *, int);
  28 static void print_address_prefix_buf ( const uint8_t *, int, char *, int);
  29
  30 /*
  31  * XXX - shouldn't there be a centralized routine for dissecting NSAPs?
  32  * See also "dissect_atm_nsap()" in epan/dissectors/packet-arp.c and
  33  * "dissect_nsap()" in epan/dissectors/packet-isup.c.
  34  */
  35 char *
  36 print_nsap_net( wmem_allocator_t *scope, tvbuff_t *tvb, const int offset, int length )
  37 {
  38   char *cur;
  39
  40   cur = (char *)wmem_alloc(scope, MAX_NSAP_LEN * 3 + 50);
  41   print_nsap_net_buf( tvb_get_ptr(tvb, offset, length), length, cur, MAX_NSAP_LEN * 3 + 50);
  42   return( cur );
  43 }
  44
  45 static void
  46 print_nsap_net_buf( const uint8_t *ad, int length, char *buf, int buf_len)
  47 {
  48   char *cur;
  49
  50   /* to do : NSAP / NET decoding */
  51
  52   if ( (length <= 0 ) || ( length > MAX_NSAP_LEN ) ) {
  53     (void) g_strlcpy(buf, "<Invalid length of NSAP>", buf_len);
  54     return;
  55   }
  56   cur = buf;
  57   if ( ( length == RFC1237_NSAP_LEN ) || ( length == RFC1237_NSAP_LEN + 1 ) ) {
  58     print_area_buf(ad, RFC1237_FULLAREA_LEN, cur, buf_len);
  59     cur += strlen( cur );
  60     print_system_id_buf( ad + RFC1237_FULLAREA_LEN, RFC1237_SYSTEMID_LEN, cur, (int) (buf_len-(cur-buf)));
  61     cur += strlen( cur );
  62     cur += snprintf(cur, buf_len-(cur-buf), "[%02x]",
  63                     ad[ RFC1237_FULLAREA_LEN + RFC1237_SYSTEMID_LEN ] );
  64     if ( length == RFC1237_NSAP_LEN + 1 ) {
  65       snprintf(cur, (int) (buf_len-(cur-buf)), "-%02x", ad[ length -1 ] );
  66     }
  67   }
  68   else {    /* probably format as standard */
  69     /* XXX - this is an NSAP, not an area address/address prefix */
  70     print_area_buf( ad, length, buf, buf_len);
  71   }
  72 } /* print_nsap */
  73
  74 char *
  75 print_system_id(wmem_allocator_t* scope, const uint8_t *ad, int length )
  76 {
  77   char         *cur;
  78
  79   cur = (char *)wmem_alloc(scope, MAX_SYSTEMID_LEN * 3 + 5);
  80   print_system_id_buf(ad, length, cur, MAX_SYSTEMID_LEN * 3 + 5);
  81   return( cur );
  82 }
  83
  84 char *
  85 tvb_print_system_id( wmem_allocator_t *scope, tvbuff_t *tvb, const int offset, int length )
  86 {
  87   return( print_system_id(scope, tvb_get_ptr(tvb, offset, length), length) );
  88 }
  89
  90 void
  91 print_system_id_buf( const uint8_t *ad, int length, char *buf, int buf_len)
  92 {
  93   char         *cur;
  94   int           tmp;
  95
  96   if ( ( length <= 0 ) || ( length > MAX_SYSTEMID_LEN ) ) {
  97     (void) g_strlcpy(buf, "<Invalid length of SYSTEM ID>", buf_len);
  98     return;
  99   }
 100
 101   cur = buf;
 102   if ( ( 6 == length ) || /* System-ID */
 103        ( 7 == length ) || /* LAN-ID */
 104        ( 8 == length )) { /* LSP-ID */
 105     cur += snprintf(cur, buf_len, "%02x%02x.%02x%02x.%02x%02x", ad[0], ad[1],
 106                     ad[2], ad[3], ad[4], ad[5] );
 107     if ( ( 7 == length ) ||
 108          ( 8 == length )) {
 109         cur += snprintf(cur, buf_len-(cur-buf), ".%02x", ad[6] );
 110     }
 111     if ( 8 == length ) {
 112         snprintf(cur, buf_len-(cur-buf), "-%02x", ad[7] );
 113     }
 114   }
 115   else {
 116     tmp = 0;
 117     while ( tmp < length / 4 ) { /* 16 / 4 == 4 > four Octets left to print */
 118       cur += snprintf(cur, buf_len-(cur-buf), "%02x", ad[tmp++] );
 119       cur += snprintf(cur, buf_len-(cur-buf), "%02x", ad[tmp++] );
 120       cur += snprintf(cur, buf_len-(cur-buf), "%02x", ad[tmp++] );
 121       cur += snprintf(cur, buf_len-(cur-buf), "%02x.", ad[tmp++] );
 122     }
 123     if ( 1 == tmp ) {   /* Special case for Designated IS */
 124       cur--;
 125       snprintf(cur, buf_len-(cur-buf), ".%02x", ad[tmp] );
 126     }
 127     else {
 128       for ( ; tmp < length; ) {  /* print the rest without dot */
 129         cur += snprintf(cur, buf_len-(cur-buf), "%02x", ad[tmp++] );
 130       }
 131     }
 132   }
 133 }
 134
 135 char *
 136 print_area(wmem_allocator_t *scope, tvbuff_t *tvb, const int offset, int length)
 137 {
 138   char *cur;
 139
 140   cur = (char *)wmem_alloc(scope, MAX_AREA_LEN * 3 + 20);
 141   print_area_buf(tvb_get_ptr(tvb, offset, length), length, cur, MAX_AREA_LEN * 3 + 20);
 142   return cur;
 143 }
 144
 145 /*
 146  * Note: length is in units of half-octets.
 147  */
 148 char *
 149 print_address_prefix(wmem_allocator_t *scope, tvbuff_t *tvb, const int offset, int length)
 150 {
 151   char *cur;
 152
 153   cur = (char *)wmem_alloc(scope, MAX_AREA_LEN * 3 + 20);
 154   print_address_prefix_buf(tvb_get_ptr(tvb, offset, (length+1)/2), length, cur, MAX_AREA_LEN * 3 + 20);
 155   return cur;
 156 }
 157
 158 /*
 159  * Note: length is in units of octets.
 160  */
 161 static void
 162 print_area_buf(const uint8_t *ad, int length, char *buf, int buf_len)
 163 {
 164   print_address_prefix_buf(ad, length*2, buf, buf_len);
 165 }
 166
 167 /*
 168  * Note: length is in units of half-octets.
 169  */
 170 static void
 171 print_address_prefix_buf(const uint8_t *ad, int length, char *buf, int buf_len)
 172 {
 173   char *cur;
 174   int  tmp  = 0;
 175
 176   /* to do : all real area decoding now: NET is assumed if id len is 1 more byte
 177    */
 178   if (length <= 0 || length > MAX_AREA_LEN*2) {
 179     (void) g_strlcpy(buf, "<Invalid length of AREA>", buf_len);
 180     return;
 181   }
 182
 183   cur = buf;
 184   /* Check the AFI and length. */
 185   if ( (  ( NSAP_IDI_ISO_DCC_BIN      == *ad )
 186        || ( NSAP_IDI_ISO_6523_ICD_BIN == *ad )
 187        )
 188        &&
 189        (  ( RFC1237_FULLAREA_LEN*2       ==  length )
 190        || ( (RFC1237_FULLAREA_LEN + 1)*2 ==  length )
 191        )
 192      ) {    /* AFI is good and length is long enough  */
 193
 194     /* The AFI is either ISO DCC, binary or ISO 6523-ICD, binary,
 195      * and the area length corresponds either to the area length
 196      * for RFC 1237 (GOSIP) addresses or that length + 1.
 197      *
 198      * XXX - RFC 1237 doesn't mention ISO DCC, binary, as a valid
 199      * AFI; is that from GOSIP Version 1?  If it's ISO DCC, binary,
 200      * the IDI is 3 digits, i.e. 1 1/2 octets.
 201      */
 202     /* there used to be a check for (length > RFC1237_FULLAREA_LEN + 1) here,
 203      * in order to report an invalied length of AREA for DCC / ISO 6523 AFI,
 204      * but that can *never* be the case because the if() test above explicitly
 205      * tests for (length == RFC1237_FULLAREA_LEN) or (length == RFC1237_FULLAREA_LEN + 1)
 206      */
 207
 208     /* Show the one-octet AFI, the two-octet IDI, the one-octet DFI, the
 209      * 3-octet AA, and the 2 reserved octets.
 210      */
 211     cur += snprintf(cur, buf_len-(cur-buf), "[%02x|%02x:%02x][%02x|%02x:%02x:%02x|%02x:%02x]",
 212                     ad[0], ad[1], ad[2], ad[3], ad[4],
 213                     ad[5], ad[6], ad[7], ad[8] );
 214     /* Show the 2-octet RD and the 2-octet Area. */
 215     cur += snprintf(cur, buf_len-(cur-buf), "[%02x:%02x|%02x:%02x]",
 216                     ad[9], ad[10],  ad[11], ad[12] );
 217     /* Show whatever the heck this is; it's not specified by RFC 1237,
 218      * but we also handle 14-octet areas.  Is it the "Designated IS"
 219      * stuff mentioned below?  (I didn't find anything in the IS-IS
 220      * spec about that.)
 221      */
 222     if ( (RFC1237_FULLAREA_LEN + 1)*2 == length )
 223       snprintf(cur, buf_len-(cur-buf), "-[%02x]", ad[13] );
 224   }
 225   else {
 226     /* This doesn't look like a full RFC 1237 IS-IS area, so all we know
 227      * is that the first octet is an AFI.  Print it separately from all
 228      * the other octets.
 229      */
 230     if ( length == RFC1237_AREA_LEN*2 ) {
 231       /* XXX - RFC1237_AREA_LEN, which is 3 octets, doesn't seem to
 232        * correspond to anything in RFC 1237.  Where did it come from?
 233        */
 234       snprintf(buf, buf_len, "%02x.%02x%02x", ad[0], ad[1], ad[2] );
 235       return;
 236     }
 237     if ( length == 4*2 ) {
 238       snprintf(buf, buf_len, "%02x%02x%02x%02x", ad[0], ad[1], ad[2], ad[3] );
 239       return;
 240     }
 241     while ( tmp < length / 8 ) {      /* 32/8==4 > four Octets left to print */
 242       cur += snprintf(cur, buf_len-(cur-buf), "%02x", ad[tmp++] );
 243       cur += snprintf(cur, buf_len-(cur-buf), "%02x", ad[tmp++] );
 244       cur += snprintf(cur, buf_len-(cur-buf), "%02x", ad[tmp++] );
 245       cur += snprintf(cur, buf_len-(cur-buf), "%02x.", ad[tmp++] );
 246     }
 247     if ( 2 == tmp ) {                     /* Special case for Designated IS */
 248       cur--;
 249       snprintf(cur, buf_len-(cur-buf), "-%02x", ad[tmp] );
 250     }
 251     else {
 252       for ( ; tmp < length / 2; ) {  /* print the rest without dot or dash */
 253         cur += snprintf(cur, buf_len-(cur-buf), "%02x", ad[tmp++] );
 254       }
 255       /* Odd half-octet? */
 256       if (length & 1) {
 257         /* Yes - print it (it's the upper half-octet) */
 258         snprintf(cur, buf_len-(cur-buf), "%x", (ad[tmp] & 0xF0)>>4 );
 259       }
 260     }
 261   }
 262 } /* print_address_prefix_buf */
 263
 264 /******************************************************************************
 265  * OSI Address Type
 266  ******************************************************************************/
 267 static int osi_address_type = -1;
 268
 269 static int osi_address_to_str(const address* addr, char *buf, int buf_len)
 270 {
 271     print_nsap_net_buf((const uint8_t *)addr->data, addr->len, buf, buf_len);
 272     return (int)strlen(buf)+1;
 273 }
 274
 275 static int osi_address_str_len(const address* addr _U_)
 276 {
 277     return MAX_NSAP_LEN * 3 + 50;
 278 }
 279
 280 int get_osi_address_type(void)
 281 {
 282     return osi_address_type;
 283 }
 284
 285 void register_osi_address_type(void)
 286 {
 287     if (osi_address_type != -1)
 288         return;
 289
 290     osi_address_type = address_type_dissector_register("AT_OSI", "OSI Address", osi_address_to_str, osi_address_str_len, NULL, NULL, NULL, NULL, NULL);
 291 }
 292
 293
 294 /*
 295  * Editor modelines
 296  *
 297  * Local Variables:
 298  * c-basic-offset: 2
 299  * tab-width: 8
 300  * indent-tabs-mode: nil
 301  * End:
 302  *
 303  * ex: set shiftwidth=2 tabstop=8 expandtab:
 304  * :indentSize=2:tabSize=8:noTabs=true:
 305  */