Add code to check the AAL5 CRC, and report it as a CRC rather than as a

checksum.

svn path=/trunk/; revision=6882

1 files changed, 134 insertions, 7 deletions

diff --git a/packet-atm.c b/packet-atm.c
index 36329559cd..4e32dd7043 100644
--- a/packet-atm.c
+++ b/packet-atm.c
@@ -1,7 +1,7 @@
 /* packet-atm.c
  * Routines for ATM packet disassembly
  *
- * $Id: packet-atm.c,v 1.53 2003/01/09 01:55:11 guy Exp $
+ * $Id: packet-atm.c,v 1.54 2003/01/09 02:55:21 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@ethereal.com>
@@ -788,6 +788,130 @@ capture_atm(const union wtap_pseudo_header *pseudo_header, const guchar *pd,
     ld->other++;
 }
 
+/*
+ * Charles Michael Heard's CRC-32 code, from
+ *
+ *	http://cell-relay.indiana.edu/cell-relay/publications/software/CRC/32bitCRC.c.html
+ *
+ * with the CRC table initialized with values computed by
+ * his "gen_crc_table()" routine, rather than by calling that routine
+ * at run time, and with various data type cleanups.
+ */
+
+/* crc32h.c -- package to compute 32-bit CRC one byte at a time using   */
+/*             the high-bit first (Big-Endian) bit ordering convention  */
+/*                                                                      */
+/* Synopsis:                                                            */
+/*  gen_crc_table() -- generates a 256-word table containing all CRC    */
+/*                     remainders for every possible 8-bit byte.  It    */
+/*                     must be executed (once) before any CRC updates.  */
+/*                                                                      */
+/*  unsigned update_crc(crc_accum, data_blk_ptr, data_blk_size)         */
+/*           unsigned crc_accum; char *data_blk_ptr; int data_blk_size; */
+/*           Returns the updated value of the CRC accumulator after     */
+/*           processing each byte in the addressed block of data.       */
+/*                                                                      */
+/*  It is assumed that an unsigned long is at least 32 bits wide and    */
+/*  that the predefined type char occupies one 8-bit byte of storage.   */
+/*                                                                      */
+/*  The generator polynomial used for this version of the package is    */
+/*  x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0 */
+/*  as specified in the Autodin/Ethernet/ADCCP protocol standards.      */
+/*  Other degree 32 polynomials may be substituted by re-defining the   */
+/*  symbol POLYNOMIAL below.  Lower degree polynomials must first be    */
+/*  multiplied by an appropriate power of x.  The representation used   */
+/*  is that the coefficient of x^0 is stored in the LSB of the 32-bit   */
+/*  word and the coefficient of x^31 is stored in the most significant  */
+/*  bit.  The CRC is to be appended to the data most significant byte   */
+/*  first.  For those protocols in which bytes are transmitted MSB      */
+/*  first and in the same order as they are encountered in the block    */
+/*  this convention results in the CRC remainder being transmitted with */
+/*  the coefficient of x^31 first and with that of x^0 last (just as    */
+/*  would be done by a hardware shift register mechanization).          */
+/*                                                                      */
+/*  The table lookup technique was adapted from the algorithm described */
+/*  by Avram Perez, Byte-wise CRC Calculations, IEEE Micro 3, 40 (1983).*/
+
+static const guint32 crc_table[256] = {
+	0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
+	0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
+	0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
+	0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
+	0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9,
+	0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
+	0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011,
+	0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
+	0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
+	0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
+	0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
+	0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
+	0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49,
+	0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
+	0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
+	0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
+	0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae,
+	0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
+	0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
+	0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
+	0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
+	0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
+	0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066,
+	0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
+	0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e,
+	0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
+	0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
+	0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
+	0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
+	0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
+	0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
+	0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
+	0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
+	0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
+	0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f,
+	0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
+	0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47,
+	0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
+	0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
+	0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
+	0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
+	0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
+	0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f,
+	0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
+	0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
+	0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
+	0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f,
+	0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
+	0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
+	0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
+	0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
+	0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
+	0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30,
+	0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
+	0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088,
+	0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
+	0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
+	0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
+	0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
+	0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
+	0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
+	0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
+	0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
+	0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4,
+};
+
+static guint32
+update_crc(guint32 crc_accum, const guint8 *data_blk_ptr, int data_blk_size)
+{
+  register int i, j;
+
+  /* update the CRC on the data block one byte at a time */
+  for (j = 0; j < data_blk_size;  j++) {
+    i = ( (int) ( crc_accum >> 24) ^ *data_blk_ptr++ ) & 0xff;
+    crc_accum = ( crc_accum << 8 ) ^ crc_table[i];
+  }
+  return crc_accum;
+}
+
 static void
 dissect_reassembled_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
     proto_tree *atm_tree, gboolean truncated)
@@ -796,6 +920,8 @@ dissect_reassembled_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
   guint16      aal5_length;
   int          pad_length;
   tvbuff_t     *next_tvb;
+  guint32      crc;
+  guint32      calc_crc;
 
   /*
    * This is reassembled traffic, so the cell headers are missing;
@@ -857,7 +983,7 @@ dissect_reassembled_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 		pinfo->pseudo_header->atm.aal5t_u2u & 0xFF);
         proto_tree_add_text(atm_tree, tvb, 0, 0, "AAL5 len: %u",
 		pinfo->pseudo_header->atm.aal5t_len);
-        proto_tree_add_text(atm_tree, tvb, 0, 0, "AAL5 checksum: 0x%08X",
+        proto_tree_add_text(atm_tree, tvb, 0, 0, "AAL5 CRC: 0x%08X",
 		pinfo->pseudo_header->atm.aal5t_chksum);
       }
     }
@@ -897,11 +1023,12 @@ dissect_reassembled_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 		tvb_get_guint8(tvb, length - 7));
         proto_tree_add_text(atm_tree, tvb, length - 6, 2, "AAL5 len: %u",
 		aal5_length);
-        /*
-         * XXX - check the checksum.
-         */
-        proto_tree_add_text(atm_tree, tvb, length - 4, 4, "AAL5 checksum: 0x%08X",
-		tvb_get_ntohl(tvb, length - 4));
+        crc = tvb_get_ntohl(tvb, length - 4);
+        calc_crc = update_crc(0xFFFFFFFF, tvb_get_ptr(tvb, 0, length),
+		length);
+        proto_tree_add_text(atm_tree, tvb, length - 4, 4,
+		"AAL5 CRC (%s): 0x%08X",
+		(calc_crc == 0xC704DD7B) ? "correct" : "incorrect", crc);
       }
       next_tvb = tvb_new_subset(tvb, 0, aal5_length, aal5_length);
     }