Check the CRC-10 on AAL3/4 and OAM cells.

svn path=/trunk/; revision=6884

1 files changed, 74 insertions, 5 deletions

diff --git a/packet-atm.c b/packet-atm.c
index 546d00f7d5..51df856d56 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 1.55 2003/01/09 03:45:34 guy Exp $
+ * $Id: packet-atm.c,v 1.56 2003/01/09 04:11:08 guy Exp $
  *
  * Ethereal - Network traffic analyzer
  * By Gerald Combs <gerald@ethereal.com>
@@ -1187,6 +1187,65 @@ static const value_string pt_vals[] = {
 	{ 0, NULL }
 };
 
+/*
+ * Charles Michael Heard's CRC-10 code, from
+ *
+ *	http://cell-relay.indiana.edu/cell-relay/publications/software/CRC/crc10.html
+ *
+ * with the CRC table initialized with values computed by
+ * his "gen_byte_crc10_table()" routine, rather than by calling that
+ * routine at run time, and with various data type cleanups.
+ */
+static const guint16 byte_crc10_table[256] = {
+	0x0000, 0x0233, 0x0255, 0x0066, 0x0299, 0x00aa, 0x00cc, 0x02ff,
+	0x0301, 0x0132, 0x0154, 0x0367, 0x0198, 0x03ab, 0x03cd, 0x01fe,
+	0x0031, 0x0202, 0x0264, 0x0057, 0x02a8, 0x009b, 0x00fd, 0x02ce,
+	0x0330, 0x0103, 0x0165, 0x0356, 0x01a9, 0x039a, 0x03fc, 0x01cf,
+	0x0062, 0x0251, 0x0237, 0x0004, 0x02fb, 0x00c8, 0x00ae, 0x029d,
+	0x0363, 0x0150, 0x0136, 0x0305, 0x01fa, 0x03c9, 0x03af, 0x019c,
+	0x0053, 0x0260, 0x0206, 0x0035, 0x02ca, 0x00f9, 0x009f, 0x02ac,
+	0x0352, 0x0161, 0x0107, 0x0334, 0x01cb, 0x03f8, 0x039e, 0x01ad,
+	0x00c4, 0x02f7, 0x0291, 0x00a2, 0x025d, 0x006e, 0x0008, 0x023b,
+	0x03c5, 0x01f6, 0x0190, 0x03a3, 0x015c, 0x036f, 0x0309, 0x013a,
+	0x00f5, 0x02c6, 0x02a0, 0x0093, 0x026c, 0x005f, 0x0039, 0x020a,
+	0x03f4, 0x01c7, 0x01a1, 0x0392, 0x016d, 0x035e, 0x0338, 0x010b,
+	0x00a6, 0x0295, 0x02f3, 0x00c0, 0x023f, 0x000c, 0x006a, 0x0259,
+	0x03a7, 0x0194, 0x01f2, 0x03c1, 0x013e, 0x030d, 0x036b, 0x0158,
+	0x0097, 0x02a4, 0x02c2, 0x00f1, 0x020e, 0x003d, 0x005b, 0x0268,
+	0x0396, 0x01a5, 0x01c3, 0x03f0, 0x010f, 0x033c, 0x035a, 0x0169,
+	0x0188, 0x03bb, 0x03dd, 0x01ee, 0x0311, 0x0122, 0x0144, 0x0377,
+	0x0289, 0x00ba, 0x00dc, 0x02ef, 0x0010, 0x0223, 0x0245, 0x0076,
+	0x01b9, 0x038a, 0x03ec, 0x01df, 0x0320, 0x0113, 0x0175, 0x0346,
+	0x02b8, 0x008b, 0x00ed, 0x02de, 0x0021, 0x0212, 0x0274, 0x0047,
+	0x01ea, 0x03d9, 0x03bf, 0x018c, 0x0373, 0x0140, 0x0126, 0x0315,
+	0x02eb, 0x00d8, 0x00be, 0x028d, 0x0072, 0x0241, 0x0227, 0x0014,
+	0x01db, 0x03e8, 0x038e, 0x01bd, 0x0342, 0x0171, 0x0117, 0x0324,
+	0x02da, 0x00e9, 0x008f, 0x02bc, 0x0043, 0x0270, 0x0216, 0x0025,
+	0x014c, 0x037f, 0x0319, 0x012a, 0x03d5, 0x01e6, 0x0180, 0x03b3,
+	0x024d, 0x007e, 0x0018, 0x022b, 0x00d4, 0x02e7, 0x0281, 0x00b2,
+	0x017d, 0x034e, 0x0328, 0x011b, 0x03e4, 0x01d7, 0x01b1, 0x0382,
+	0x027c, 0x004f, 0x0029, 0x021a, 0x00e5, 0x02d6, 0x02b0, 0x0083,
+	0x012e, 0x031d, 0x037b, 0x0148, 0x03b7, 0x0184, 0x01e2, 0x03d1,
+	0x022f, 0x001c, 0x007a, 0x0249, 0x00b6, 0x0285, 0x02e3, 0x00d0,
+	0x011f, 0x032c, 0x034a, 0x0179, 0x0386, 0x01b5, 0x01d3, 0x03e0,
+	0x021e, 0x002d, 0x004b, 0x0278, 0x0087, 0x02b4, 0x02d2, 0x00e1,
+};
+
+/* update the data block's CRC-10 remainder one byte at a time */
+static guint16
+update_crc10_by_bytes(guint16 crc10_accum, const guint8 *data_blk_ptr,
+    int data_blk_size)
+{
+  register int i;
+
+  for (i = 0;  i < data_blk_size; i++) {
+      crc10_accum = ((crc10_accum << 8) & 0x3ff)
+                     ^ byte_crc10_table[( crc10_accum >> 2) & 0xff]
+                                                    ^ *data_blk_ptr++;
+  }
+  return crc10_accum;
+}
+
 static const value_string st_vals[] = {
 	{ 2, "BOM" },
 	{ 0, "COM" },
@@ -1240,6 +1299,8 @@ dissect_atm_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
   guint16      vci;
   guint16      aal3_4_hdr, aal3_4_trlr;
   guint16      oam_crc;
+  gint         length;
+  guint16      crc10;
   tvbuff_t     *next_tvb;
 
   octet = tvb_get_guint8(tvb, 0);
@@ -1321,8 +1382,12 @@ dissect_atm_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
     aal3_4_trlr = tvb_get_ntohs(tvb, offset);
     proto_tree_add_text(aal_tree, tvb, offset, 2, "Length Indicator: %u",
 		(aal3_4_trlr >> 10) & 0x3F);
-    proto_tree_add_text(aal_tree, tvb, offset, 2, "CRC: 0x%03x",
-		aal3_4_trlr & 0x3FF);
+    length = tvb_length_remaining(tvb, 5);
+    crc10 = update_crc10_by_bytes(0, tvb_get_ptr(tvb, 5, length),
+	length);
+    proto_tree_add_text(aal_tree, tvb, offset, 2, "CRC: 0x%03x (%s)",
+		aal3_4_trlr & 0x3FF,
+		(crc10 == 0) ? "correct" : "incorrect");
     break;
 
   case AAL_OAMCELL:
@@ -1360,9 +1425,13 @@ dissect_atm_cell(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
     proto_tree_add_text(aal_tree, tvb, offset, 45, "Function-specific information");
     offset += 45;
 
+    length = tvb_length_remaining(tvb, 5);
+    crc10 = update_crc10_by_bytes(0, tvb_get_ptr(tvb, 5, length),
+	length);
     oam_crc = tvb_get_ntohs(tvb, offset);
-    proto_tree_add_text(aal_tree, tvb, offset, 2, "CRC-10: 0x%03x",
-		oam_crc & 0x3FF);
+    proto_tree_add_text(aal_tree, tvb, offset, 2, "CRC-10: 0x%03x (%s)",
+		oam_crc & 0x3FF,
+		(crc10 == 0) ? "correct" : "incorrect");
     break;
 
   default: