Merge pull request #172 from CESNET/nettisa_time_comparison

Nettisa - fix time comparison

Author: SiskaPavel

include/ipfixprobe/utils.hpp

@@ -145,5 +145,11 @@ T str2num(std::string str, typename std::enable_if<is_uint<T>()>::type * = nullp
    return static_cast<T>(tmp);
 }
 
+/**
+ * @brief Convert struct Timeval to microseconds
+ */
+uint64_t timeval2usec(const struct timeval& tv);
+
 }
-#endif /* IPXP_UTILS_HPP */
+
+#endif /* IPXP_UTILS_HPP */

process/nettisa.cpp

@@ -9,6 +9,7 @@
 
 #include <cmath>
 #include <iostream>
+#include <ipfixprobe/utils.hpp>
 
 namespace ipxp {
 
@@ -21,14 +22,6 @@ __attribute__((constructor)) static void register_this_plugin()
     RecordExtNETTISA::REGISTERED_ID = register_extension();
 }
 
-NETTISAPlugin::NETTISAPlugin() {}
-
-NETTISAPlugin::~NETTISAPlugin() {}
-
-void NETTISAPlugin::init(const char* params) {}
-
-void NETTISAPlugin::close() {}
-
 ProcessPlugin* NETTISAPlugin::copy()
 {
     return new NETTISAPlugin(*this);
@@ -41,8 +34,11 @@ void NETTISAPlugin::update_record(
 {
     float variation_from_mean = pkt.payload_len_wire - nettisa_data->mean;
     uint32_t n = rec.dst_packets + rec.src_packets;
-    long diff_time = pkt.ts.tv_usec - nettisa_data->prev_time;
-    nettisa_data->prev_time = pkt.ts.tv_usec;
+    uint64_t packet_time = timeval2usec(pkt.ts);
+    uint64_t record_time = timeval2usec(rec.time_first);
+    float diff_time = fmax(packet_time - nettisa_data->prev_time, 0);
+    nettisa_data->sum_payload += pkt.payload_len_wire;
+    nettisa_data->prev_time = packet_time;
     // MEAN
     nettisa_data->mean += (variation_from_mean) / n;
     // MIN
@@ -57,7 +53,7 @@ void NETTISAPlugin::update_record(
     nettisa_data->kurtosis += pow(variation_from_mean, 4);
     // MEAN SCALED TIME
     nettisa_data->mean_scaled_time
-        += (pkt.ts.tv_usec - rec.time_first.tv_usec - nettisa_data->mean_scaled_time) / n;
+        += (packet_time - record_time - nettisa_data->mean_scaled_time) / n;
     // MEAN TIME DIFFERENCES
     nettisa_data->mean_difftimes += (diff_time - nettisa_data->mean_difftimes) / n;
     // MIN
@@ -78,7 +74,7 @@ int NETTISAPlugin::post_create(Flow& rec, const Packet& pkt)
     RecordExtNETTISA* nettisa_data = new RecordExtNETTISA();
     rec.add_extension(nettisa_data);
 
-    nettisa_data->prev_time = pkt.ts.tv_usec;
+    nettisa_data->prev_time = timeval2usec(pkt.ts);
 
     update_record(nettisa_data, pkt, rec);
     return 0;
@@ -88,6 +84,7 @@ int NETTISAPlugin::post_update(Flow& rec, const Packet& pkt)
 {
     RecordExtNETTISA* nettisa_data
         = (RecordExtNETTISA*) rec.get_extension(RecordExtNETTISA::REGISTERED_ID);
+
     update_record(nettisa_data, pkt, rec);
     return 0;
 }
@@ -97,15 +94,26 @@ void NETTISAPlugin::pre_export(Flow& rec)
     RecordExtNETTISA* nettisa_data
         = (RecordExtNETTISA*) rec.get_extension(RecordExtNETTISA::REGISTERED_ID);
     uint32_t n = rec.src_packets + rec.dst_packets;
-    nettisa_data->switching_ratio = nettisa_data->switching_ratio / ((n - 1) / 2);
-    nettisa_data->stdev = pow(
-        (nettisa_data->root_mean_square / n) - pow((rec.src_bytes + rec.dst_bytes) / n, 2),
-        0.5);
+    if (n == 1) {
+        nettisa_data->switching_ratio = 0;
+        nettisa_data->stdev = 0;
+        nettisa_data->kurtosis = 0;
+        nettisa_data->time_distribution = 0;
+    } else {
+        nettisa_data->switching_ratio = nettisa_data->switching_ratio / n;
+        nettisa_data->stdev = pow(
+            (nettisa_data->root_mean_square / n) - pow(nettisa_data->sum_payload / n, 2),
+            0.5);
+        if (nettisa_data->stdev == 0) {
+            nettisa_data->kurtosis = 0;
+        } else {
+            nettisa_data->kurtosis = nettisa_data->kurtosis / (n * pow(nettisa_data->stdev, 4));
+        }
+        nettisa_data->time_distribution = (nettisa_data->time_distribution / (n - 1))
+            / (nettisa_data->max_difftimes - nettisa_data->min);
+    }
     nettisa_data->root_mean_square = pow(nettisa_data->root_mean_square / n, 0.5);
     nettisa_data->average_dispersion = nettisa_data->average_dispersion / n;
-    nettisa_data->kurtosis = nettisa_data->kurtosis / (n * pow(nettisa_data->stdev, 4));
-    nettisa_data->time_distribution = (nettisa_data->time_distribution / (n - 1))
-        / (nettisa_data->max_difftimes - nettisa_data->min);
 }
 
 } // namespace ipxp

process/nettisa.hpp

@@ -27,8 +27,10 @@
 namespace ipxp {
 
 #define NETTISA_UNIREC_TEMPLATE                                                                    \
-    "NTS_MEAN,NTS_MIN,NTS_MAX,NTS_STDEV,NTS_KURTOSIS,NTS_ROOT_MEAN_SQUARE,NTS_AVERAGE_DISPERSION," \
-    "NTS_MEAN_SCALED_TIME,NTS_MEAN_DIFFTIMES,NTS_MIN_DIFFTIMES,NTS_MAX_DIFFTIMES,NTS_TIME_"        \
+    "NTS_MEAN,NTS_MIN,NTS_MAX,NTS_STDEV,NTS_KURTOSIS,NTS_ROOT_MEAN_SQUARE,NTS_"                    \
+    "AVERAGE_DISPERSION,"                                                                          \
+    "NTS_MEAN_SCALED_TIME,NTS_MEAN_DIFFTIMES,NTS_MIN_DIFFTIMES,NTS_MAX_"                           \
+    "DIFFTIMES,NTS_TIME_"                                                                          \
     "DISTRIBUTION,"                                                                                \
     "NTS_SWITCHING_RATIO"
 
@@ -68,7 +70,8 @@ struct RecordExtNETTISA : public RecordExt {
     float switching_ratio;
 
     uint16_t prev_payload;
-    long prev_time;
+    uint64_t prev_time;
+    uint64_t sum_payload;
 
     RecordExtNETTISA()
         : RecordExt(REGISTERED_ID)
@@ -89,6 +92,7 @@ struct RecordExtNETTISA : public RecordExt {
 
         prev_payload = 0;
         prev_time = 0;
+        sum_payload = 0;
     }
 
 #ifdef WITH_NEMEA
@@ -112,7 +116,7 @@ struct RecordExtNETTISA : public RecordExt {
     const char* get_unirec_tmplt() const { return NETTISA_UNIREC_TEMPLATE; }
 #endif // ifdef WITH_NEMEA
 
-    constexpr int get_ipfix_size() const noexcept
+    int get_ipfix_size() const noexcept
     {
         return sizeof(mean) + sizeof(min) + sizeof(max) + sizeof(stdev) + sizeof(kurtosis)
             + sizeof(root_mean_square) + sizeof(average_dispersion) + sizeof(mean_scaled_time)
@@ -169,10 +173,6 @@ struct RecordExtNETTISA : public RecordExt {
  */
 class NETTISAPlugin : public ProcessPlugin {
 public:
-    NETTISAPlugin();
-    ~NETTISAPlugin();
-    void init(const char* params);
-    void close();
     OptionsParser* get_parser() const { return new OptionsParser("nettisa", "Parse NetTiSA flow"); }
     std::string get_name() const { return "nettisa"; }
     RecordExt* get_ext() const { return new RecordExtNETTISA(); }

utils.cpp

@@ -132,4 +132,10 @@ uint32_t variable2ipfix_buffer(uint8_t* buffer2write, uint8_t* buffer2read, uint
     return ptr + len;
 }
 
-} // namespace ipxp
+uint64_t timeval2usec(const struct timeval& tv)
+{
+   constexpr size_t usec_in_sec = 1000000;
+   return tv.tv_sec * usec_in_sec + tv.tv_usec;
+}
+
+} // namespace ipxp