Add ICMP tap support, and add a tshark tap to measure such things as:

  * Number of ICMP echo requests, replies, lost replies and percent loss.
  * Min, Max, Average SRT (Service Response Time), and standard deviation.
(This is my first tap, so hopefully I didn't miss something, but we'll see ...)
TODO: Add a Wireshark tap.



git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@36480 f5534014-38df-0310-8fa8-9805f1628bb7

1 files changed, 269 insertions, 0 deletions

diff --git a/tap-icmpstat.c b/tap-icmpstat.c
new file mode 100755
index 0000000000..8ff7ff4fe4
--- /dev/null
+++ b/tap-icmpstat.c
@@ -0,0 +1,269 @@
+/* tap-icmpstat.c
+ * icmpstat   2011 Christopher Maynard
+ *
+ * $Id$
+ *
+ * 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.
+ */
+
+/* This module provides icmp echo request/reply SRT statistics to tshark.
+ * It is only used by tshark and not wireshark
+ *
+ * It was based on tap-rpcstat.c and doc/README.tapping.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdio.h>
+
+#ifdef HAVE_SYS_TYPES_H
+# include <sys/types.h>
+#endif
+
+#include <string.h>
+#include "epan/packet_info.h"
+#include <epan/tap.h>
+#include <epan/stat_cmd_args.h>
+#include <epan/dissectors/packet-icmp.h>
+#include <math.h>
+
+/* used to keep track of the ICMP statistics */
+typedef struct _icmpstat_t {
+    char *filter;
+    GSList *rt_list;
+    guint num_rqsts;
+    guint num_resps;
+    double min_msecs;
+    double max_msecs;
+    double tot_msecs;
+} icmpstat_t;
+
+
+/* This callback is never used by tshark but it is here for completeness. When
+ * registering below, we could just have left this function as NULL.
+ *
+ * When used by wireshark, this function will be called whenever we would need
+ * to reset all state, such as when wireshark opens a new file, when it starts
+ * a new capture, when it rescans the packetlist after some prefs have changed,
+ * etc.
+ *
+ * So if your application has some state it needs to clean up in those
+ * situations, here is a good place to put that code.
+ */
+static void
+icmpstat_reset(void *tapdata)
+{
+    icmpstat_t *icmpstat = tapdata;
+
+    g_slist_free(icmpstat->rt_list);
+    icmpstat->rt_list = NULL;
+    icmpstat->num_rqsts = 0;
+    icmpstat->num_resps = 0;
+    icmpstat->min_msecs = 1.0 * G_MAXUINT;
+    icmpstat->max_msecs = 0.0;
+    icmpstat->tot_msecs = 0.0;
+}
+
+
+/* This callback is invoked whenever the tap system has seen a packet we might
+ * be interested in.  The function is to be used to only update internal state
+ * information in the *tapdata structure, and if there were state changes which
+ * requires the window to be redrawn, return 1 and (*draw) will be called
+ * sometime later.
+ *
+ * This function should be as lightweight as possible since it executes
+ * together with the normal wireshark dissectors.  Try to push as much
+ * processing as possible into (*draw) instead since that function executes
+ * asynchronously and does not affect the main thread's performance.
+ *
+ * If it is possible, try to do all "filtering" explicitly since you will get
+ * MUCH better performance than applying a similar display-filter in the
+ * register call.
+ *
+ * The third parameter is tap dependent.  Since we register this one to the
+ * "icmp" tap, the third parameter type is icmp_transaction_t.
+ *
+ * function returns :
+ *  0: no updates, no need to call (*draw) later
+ * !0: state has changed, call (*draw) sometime later
+ */
+static int
+icmpstat_packet(void *tapdata, packet_info *pinfo, epan_dissect_t *edt _U_, const void *data)
+{
+    icmpstat_t *icmpstat = tapdata;
+    const icmp_transaction_t *trans = data;
+    double *rt;
+
+    if (trans == NULL)
+        return 0;
+
+    if (trans->resp_frame) {
+        rt = g_malloc(sizeof(double));
+        if (rt == NULL)
+            return 0;
+        *rt = trans->resp_time;
+        icmpstat->rt_list = g_slist_prepend(icmpstat->rt_list, rt);
+        icmpstat->num_resps++;
+        if (icmpstat->min_msecs > trans->resp_time)
+            icmpstat->min_msecs = trans->resp_time;
+        if (icmpstat->max_msecs < trans->resp_time)
+            icmpstat->max_msecs = trans->resp_time;
+        icmpstat->tot_msecs += trans->resp_time;
+    } else if (trans->rqst_frame)
+        icmpstat->num_rqsts++;
+    else
+        return 0;
+
+    return 1;
+}
+
+
+static double compute_sdev(double average, guint num, GSList *slist)
+{
+    double diff;
+    double sq_diff_sum;
+
+    if (num == 0)
+        return 0.0;
+
+    for ( sq_diff_sum = 0.0; slist; slist = g_slist_next(slist)) {
+        diff = *(double *)slist->data - average;
+        sq_diff_sum += diff * diff;
+    }
+
+    return sqrt(sq_diff_sum / num);
+}
+
+
+/* This callback is used when tshark wants us to draw/update our data to the
+ * output device.  Since this is tshark, the only output is stdout.
+ * TShark will only call this callback once, which is when tshark has finished
+ * reading all packets and exits.
+ * If used with wireshark this may be called any time, perhaps once every 3
+ * seconds or so.
+ * This function may even be called in parallel with (*reset) or (*draw), so
+ * make sure there are no races.  The data in the icmpstat_t can thus change
+ * beneath us.  Beware!
+ *
+ * How best to display the data?  For now, following other tap statistics
+ * output, but here are a few other alternatives we might choose from:
+ *
+ * -> Windows ping output:
+ *      Ping statistics for <IP>:
+ *          Packets: Sent = <S>, Received = <R>, Lost = <L> (<LP>% loss),
+ *      Approximate round trip times in milli-seconds:
+ *          Minimum = <m>ms, Maximum = <M>ms, Average = <A>ms
+ *
+ * -> Cygwin ping output:
+ *      ----<HOST> PING Statistics----
+ *      <S> packets transmitted, <R> packets received, <LP>% packet loss
+ *      round-trip (ms)  min/avg/max/med = <m>/<M>/<A>/<D>
+ *
+ * -> Linux ping output:
+ *      --- <HOST> ping statistics ---
+ *      <S> packets transmitted, <R> received, <LP>% packet loss, time <T>ms
+ *      rtt min/avg/max/mdev = <m>/<A>/<M>/<D> ms
+ */
+static void
+icmpstat_draw(void *tapdata)
+{
+    icmpstat_t *icmpstat = tapdata;
+    unsigned int lost;
+    double average, sdev;
+
+    printf("\n");
+    printf("==========================================================================\n");
+    printf("ICMP SRT Statistics (all times in ms):\n");
+    printf("Filter: %s\n", icmpstat->filter ? icmpstat->filter : "");
+    printf("Requests  Replies   Lost      %% Loss  Min SRT   Max SRT   Avg SRT   SDEV\n");
+
+    if (icmpstat->num_rqsts) {
+        lost =  icmpstat->num_rqsts - icmpstat->num_resps;
+        average = icmpstat->tot_msecs / icmpstat->num_resps;
+        sdev = compute_sdev(average, icmpstat->num_resps, icmpstat->rt_list);
+        printf("%-10u%-10u%-10u%5.1f%%  %-10.3f%-10.3f%-10.3f%-10.3f\n",
+            icmpstat->num_rqsts, icmpstat->num_resps, lost,
+            100.0 * lost / icmpstat->num_rqsts,
+            icmpstat->min_msecs >= G_MAXUINT ? 0.0 : icmpstat->min_msecs,
+            icmpstat->max_msecs, average, sdev);
+    } else
+        printf("0         0         0           0.0%%  0.000     0.000     0.000     0.000\n");
+    printf("==========================================================================\n");
+}
+
+
+/* When called, this function will create a new instance of icmpstat.
+ *
+ * This function is called from tshark when it parses the -z icmp, arguments
+ * and it creates a new instance to store statistics in and registers this new
+ * instance for the icmp tap.
+ */
+static void
+icmpstat_init(const char *optarg, void* userdata _U_)
+{
+    icmpstat_t *icmpstat;
+    const char *filter = NULL;
+    GString *error_string;
+
+    if (strstr(optarg, "icmp,srt,"))
+        filter = optarg + strlen("icmp,srt,");
+
+    icmpstat = g_malloc0(sizeof(icmpstat_t));
+    icmpstat->min_msecs = 1.0 * G_MAXUINT;
+    if (icmpstat == NULL) {
+        fprintf(stderr, "tshark: g_malloc() fatal error.\n");
+        exit(1);
+    }
+    if (filter)
+        icmpstat->filter = g_strdup(filter);
+
+/* It is possible to create a filter and attach it to the callbacks.  Then the
+ * callbacks would only be invoked if the filter matched.
+ *
+ * Evaluating filters is expensive and if we can avoid it and not use them,
+ * then we gain performance.
+ *
+ * In this case we do the filtering for protocol and version inside the
+ * callback itself but use whatever filter the user provided.
+ */
+
+    error_string = register_tap_listener("icmp", icmpstat, icmpstat->filter,
+        TL_REQUIRES_NOTHING, icmpstat_reset, icmpstat_packet, icmpstat_draw);
+    if (error_string) {
+        /* error, we failed to attach to the tap. clean up */
+        if (icmpstat->filter)
+            g_free(icmpstat->filter);
+        g_free(icmpstat);
+
+        fprintf(stderr, "tshark: Couldn't register icmp,srt tap: %s\n",
+            error_string->str);
+        g_string_free(error_string, TRUE);
+        exit(1);
+    }
+}
+
+
+void
+register_tap_listener_icmpstat(void)
+{
+    register_stat_cmd_arg("icmp,srt", icmpstat_init, NULL);
+}
+