aboutsummaryrefslogtreecommitdiffstats
path: root/epan/crc32-tvb.c
diff options
context:
space:
mode:
authorStig Bjørlykke <stig@bjorlykke.org>2011-08-31 09:00:54 +0000
committerStig Bjørlykke <stig@bjorlykke.org>2011-08-31 09:00:54 +0000
commit5359494b1f7fbfa4fce2e98e4d9e579a0fdafff4 (patch)
tree8d6f30d58eeb9b379d0db577f7f5d9e975a1d149 /epan/crc32-tvb.c
parent48221f4dfda01b750f5d00548d8c37a578d3a53b (diff)
Second try to move crc routines to libwsutil.
This time keep the tvb routines in epan. Now we can use common crc routines outside epan. svn path=/trunk/; revision=38810
Diffstat (limited to 'epan/crc32-tvb.c')
-rw-r--r--epan/crc32-tvb.c107
1 files changed, 107 insertions, 0 deletions
diff --git a/epan/crc32-tvb.c b/epan/crc32-tvb.c
new file mode 100644
index 0000000000..91cd7c13f2
--- /dev/null
+++ b/epan/crc32-tvb.c
@@ -0,0 +1,107 @@
+/* crc32-tvb.c
+ * CRC-32 tvbuff routines
+ *
+ * $Id$
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Credits:
+ *
+ * Table from Solomon Peachy
+ * Routine from Chris Waters
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+#include <epan/tvbuff.h>
+#include <wsutil/crc32.h>
+
+
+guint32
+crc32_ccitt_tvb(tvbuff_t *tvb, guint len)
+{
+ const guint8* buf;
+
+ tvb_ensure_bytes_exist(tvb, 0, len); /* len == -1 not allowed */
+ buf = tvb_get_ptr(tvb, 0, len);
+
+ return ( crc32_ccitt_seed(buf, len, CRC32_CCITT_SEED) );
+}
+
+guint32
+crc32_ccitt_tvb_offset(tvbuff_t *tvb, guint offset, guint len)
+{
+ const guint8* buf;
+
+ tvb_ensure_bytes_exist(tvb, offset, len); /* len == -1 not allowed */
+ buf = tvb_get_ptr(tvb, offset, len);
+
+ return ( crc32_ccitt(buf, len) );
+}
+
+guint32
+crc32_ccitt_tvb_seed(tvbuff_t *tvb, guint len, guint32 seed)
+{
+ const guint8* buf;
+
+ tvb_ensure_bytes_exist(tvb, 0, len); /* len == -1 not allowed */
+ buf = tvb_get_ptr(tvb, 0, len);
+
+ return ( crc32_ccitt_seed(buf, len, seed) );
+}
+
+guint32
+crc32_ccitt_tvb_offset_seed(tvbuff_t *tvb, guint offset, guint len,
+ guint32 seed)
+{
+ const guint8* buf;
+
+ tvb_ensure_bytes_exist(tvb, offset, len); /* len == -1 not allowed */
+ buf = tvb_get_ptr(tvb, offset, len);
+
+ return ( crc32_ccitt_seed(buf, len, seed) );
+}
+
+/*
+ * IEEE 802.x version (Ethernet and 802.11, at least) - byte-swap
+ * the result of "crc32()".
+ *
+ * XXX - does this mean we should fetch the Ethernet and 802.11
+ * FCS with "tvb_get_letohl()" rather than "tvb_get_ntohl()",
+ * or is fetching it big-endian and byte-swapping the CRC done
+ * to cope with 802.x sending stuff out in reverse bit order?
+ */
+guint32
+crc32_802_tvb(tvbuff_t *tvb, guint len)
+{
+ guint32 c_crc;
+
+ c_crc = crc32_ccitt_tvb(tvb, len);
+
+ /* Byte reverse. */
+ c_crc = ((unsigned char)(c_crc>>0)<<24) |
+ ((unsigned char)(c_crc>>8)<<16) |
+ ((unsigned char)(c_crc>>16)<<8) |
+ ((unsigned char)(c_crc>>24)<<0);
+
+ return ( c_crc );
+}