- Make a distinction between ethernet padding and an ethernet trailer

- ... and make that distinction configurable for capture files that do not have padding in small frames, but do have trailers
- Add VSS-Monitoring dissector to show by the TAP inserted time- and portstamps


svn path=/trunk/; revision=40108

1 files changed, 216 insertions, 0 deletions

diff --git a/epan/dissectors/packet-vssmonitoring.c b/epan/dissectors/packet-vssmonitoring.c
new file mode 100644
index 0000000000..1f0ee4c886
--- /dev/null
+++ b/epan/dissectors/packet-vssmonitoring.c
@@ -0,0 +1,216 @@
+/* packet-vssmonitoring.c
+ * Routines for dissection of VSS-monitoring timestamp and portstamp
+ *
+ * Copyright VSS-Monitoring 2011
+ *
+ * 20111205 - First edition by Sake Blok (sake.blok@SYN-bit.nl)
+ *
+ * $Id$
+ *
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdio.h>
+#include <epan/packet.h>
+#include <epan/prefs.h>
+
+
+#define VSS_NS_MASK     0x3fffffff
+#define CLKSRC_SHIFT    30
+
+#define CLKSRC_LOCAL    0
+#define CLKSRC_NTP      1
+#define CLKSRC_GPS      2
+#define CLKSRC_PTP      3
+
+static const value_string clksrc_vals[] = {
+  { CLKSRC_LOCAL,       "Not Synced" },
+  { CLKSRC_NTP,         "NTP" },
+  { CLKSRC_GPS,         "GPS" },
+  { CLKSRC_PTP,         "PTP" },
+  { 0,                  NULL }
+};
+
+
+static int proto_vssmonitoring = -1;
+
+static int hf_vssmonitoring_time = -1;
+static int hf_vssmonitoring_clksrc = -1;
+static int hf_vssmonitoring_srcport = -1;
+
+static gint ett_vssmonitoring = -1;
+
+static gboolean vssmonitoring_use_heuristics = TRUE;
+
+static int
+dissect_vssmonitoring(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+  proto_tree    *ti = NULL, *item = NULL;
+  proto_tree    *vssmonitoring_tree = NULL;
+  guint         offset = 0;
+
+  guint         trailer_len;
+  nstime_t      vssmonitoring_time;
+  guint8        vssmonitoring_clksrc = 0;
+  guint8        vssmonitoring_srcport = 0;
+
+  struct tm     *tmp;
+
+
+  /* First get the length of the trailer */
+  trailer_len = tvb_reported_length(tvb);
+
+  /* The trailer length is a sum (of any combination) of:
+   * timestamp (8 bytes)
+   * port stamp (1 or 2 bytes)
+   * fcs (4 bytes)
+   * 
+   * This means a trailer length must not be more than 14 bytes
+   */
+  if ( trailer_len > 14 )
+    return 0;
+
+  /* ... and also a 1-byte port stamp can not co-exist with a 2-byte
+   * portstamp
+   */
+  if ( (trailer_len & 3) == 3 )
+    return 0;
+
+  if ( trailer_len & 8 ) {
+    vssmonitoring_time.secs  = tvb_get_ntohl(tvb, offset);
+    vssmonitoring_time.nsecs = tvb_get_ntohl(tvb, offset + 4);
+    vssmonitoring_clksrc     = (guint8)(((guint32)vssmonitoring_time.nsecs) >> CLKSRC_SHIFT);
+    vssmonitoring_time.nsecs &= VSS_NS_MASK;
+
+    /* There are only heuristics for timestamps, the port stamp can be any value */
+    if ( vssmonitoring_use_heuristics ) {
+
+      /* The timestamp will be based on the uptime untill the TAP is completely booted, 
+       * this takes about 60s, but use 1 hour to be sure
+       */
+      if (vssmonitoring_time.secs > 3600) {
+
+        /* Check whether the timestamp in the PCAP header and the VSS-Monitoring 
+         * differ less than 30 days, otherwise, this might not be a VSS-Monitoring
+         * timestamp
+         */
+        if ( vssmonitoring_time.secs > pinfo->fd->abs_ts.secs ) {
+          if ( vssmonitoring_time.secs - pinfo->fd->abs_ts.secs > 2592000 ) /* 30 days */
+            return 0;
+        } else {
+          if ( pinfo->fd->abs_ts.secs - vssmonitoring_time.secs > 2592000 ) /* 30 days */
+            return 0;
+        }
+      }
+
+      /* The nanoseconds field should be less than 1000000000 
+       */
+      if ( vssmonitoring_time.nsecs >= 1000000000 ) 
+        return 0;
+    }
+  }
+
+  /* All systems are go, lets dissect the VSS-Monitoring trailer */
+  if (tree) {
+    ti = proto_tree_add_item(tree, proto_vssmonitoring, 
+             tvb, 0, (trailer_len & 0xb), ENC_NA);
+    vssmonitoring_tree = proto_item_add_subtree(ti, ett_vssmonitoring);
+  }
+
+  /* Do we have a timestamp? */
+  if ( trailer_len & 8 ) {
+    if (tree) {
+      item = proto_tree_add_time(vssmonitoring_tree, hf_vssmonitoring_time, tvb, offset, 8, &vssmonitoring_time);
+      item = proto_tree_add_uint(vssmonitoring_tree, hf_vssmonitoring_clksrc, tvb, offset + 4, 1, vssmonitoring_clksrc);
+
+      tmp = localtime(&vssmonitoring_time.secs);
+      proto_item_append_text(ti, ", Timestamp: %02d:%02d:%02d.%09ld",
+          tmp->tm_hour, tmp->tm_min, tmp->tm_sec,(long)vssmonitoring_time.nsecs);
+    }
+    offset += 8;
+  }
+
+  /* Do we have a portstamp? */
+  if ( trailer_len & 3) {
+    if ( trailer_len & 1) {
+      vssmonitoring_srcport = tvb_get_guint8(tvb, offset);
+      if (tree) 
+        item = proto_tree_add_item(vssmonitoring_tree, hf_vssmonitoring_srcport, tvb, offset, 1, ENC_NA);
+      offset++;
+    } else if ( trailer_len & 2) {
+      vssmonitoring_srcport = tvb_get_ntohs(tvb, offset);
+      if (tree)
+        item = proto_tree_add_item(vssmonitoring_tree, hf_vssmonitoring_srcport, tvb, offset, 2, ENC_NA);
+      offset += 2;
+    }
+    if (tree)
+      proto_item_append_text(ti, ", Source Port: %d", vssmonitoring_srcport);
+  }
+
+  return offset;
+}
+
+void
+proto_register_vssmonitoring(void)
+{
+  static hf_register_info hf[] = {
+    { &hf_vssmonitoring_time, {
+        "Time Stamp", "vssmonitoring.time", 
+        FT_ABSOLUTE_TIME, ABSOLUTE_TIME_LOCAL, NULL, 0x0, 
+        "VSS-Monitoring Time Stamp", HFILL }},
+
+    { &hf_vssmonitoring_clksrc, {
+        "Clock Source", "vssmonitoring.clksrc", 
+        FT_UINT8, BASE_DEC, VALS(clksrc_vals), 0x0, 
+        "VSS-Monitoring Clock Source", HFILL }},
+
+    { &hf_vssmonitoring_srcport, {
+        "Src Port", "vssmonitoring.srcport", 
+        FT_UINT8, BASE_DEC, NULL, 0x0, 
+        "VSS-Monitoring Source Port", HFILL }}
+  };
+
+  static gint *ett[] = {
+    &ett_vssmonitoring
+  };
+
+  module_t *vssmonitoring_module;
+
+  proto_vssmonitoring = proto_register_protocol("VSS-Monitoring ethernet trailer", "VSS-Monitoring", "vssmonitoring");
+  proto_register_field_array(proto_vssmonitoring, hf, array_length(hf));
+  proto_register_subtree_array(ett, array_length(ett));
+
+  vssmonitoring_module = prefs_register_protocol(proto_vssmonitoring, NULL);
+
+  prefs_register_bool_preference(vssmonitoring_module, "use_heuristics",
+      "Use heuristics to verify if trailer contains VSS-Monitoring data",
+      "When enabled, Wireshark will do a check on the trailer data to verify"
+      "whether it contains VSS-Monitoring time- and port-stamps.",
+      &vssmonitoring_use_heuristics);
+}
+
+void
+proto_reg_handoff_vssmonitoring(void)
+{
+  heur_dissector_add("eth.trailer", dissect_vssmonitoring, proto_vssmonitoring);
+}