Allow configuring pcap timestamp precision

cmake/Modules/FindPCAP.cmake

@@ -75,6 +75,7 @@ include(CheckFunctionExists)
 set(CMAKE_REQUIRED_LIBRARIES ${PCAP_LIBRARY})
 check_function_exists(pcap_get_pfring_id HAVE_PF_RING)
 check_function_exists(pcap_set_immediate_mode HAVE_PCAP_IMMEDIATE_MODE)
+check_function_exists(pcap_set_tstamp_precision HAVE_PCAP_TIMESTAMP_PRECISION)
 set(CMAKE_REQUIRED_LIBRARIES)
 
 mark_as_advanced(

include/tins/sniffer.h

@@ -350,14 +350,11 @@ private:
     friend class SnifferConfiguration;
 
     void set_snap_len(unsigned snap_len);
-
     void set_buffer_size(unsigned buffer_size);
-
     void set_promisc_mode(bool promisc_enabled);
-
     void set_rfmon(bool rfmon_enabled);
-
     void set_immediate_mode(bool enabled);
+    void set_timestamp_precision(int value);
 };
 
 /**
@@ -586,6 +583,12 @@ public:
      * \param enabled The immediate mode option value.
      */
     void set_immediate_mode(bool enabled);
+
+    /**
+     * Sets the timestamp precision value
+     * \param value The timestamp option value.
+     */
+    void set_timestamp_precision(int value);
 protected:
     friend class Sniffer;
     friend class FileSniffer;
@@ -596,7 +599,8 @@ protected:
         RFMON = 4,
         PACKET_FILTER = 8,
         IMMEDIATE_MODE = 16,
-        DIRECTION = 32
+        DIRECTION = 32,
+        TIMESTAMP_PRECISION = 64,
     };
 
     void configure_sniffer_pre_activation(Sniffer& sniffer) const;
@@ -613,6 +617,7 @@ protected:
     bool rfmon_;
     bool immediate_mode_;
     pcap_direction_t direction_;
+    int timestamp_precision_;
 };
 
 template <typename Functor>

src/CMakeLists.txt

@@ -4,6 +4,10 @@ IF(HAVE_PCAP_IMMEDIATE_MODE)
     ADD_DEFINITIONS("-DHAVE_PCAP_IMMEDIATE_MODE=1")
 ENDIF()
 
+IF(HAVE_PCAP_TIMESTAMP_PRECISION)
+    ADD_DEFINITIONS("-DHAVE_PCAP_TIMESTAMP_PRECISION=1")
+ENDIF()
+
 INCLUDE_DIRECTORIES(
     ${LIBTINS_INCLUDE_DIR}
     ${OPENSSL_INCLUDE_DIR}

src/sniffer.cpp

@@ -359,6 +359,16 @@ void Sniffer::set_immediate_mode(bool enabled) {
     #endif // HAVE_PCAP_IMMEDIATE_MODE
 }
 
+void Sniffer::set_timestamp_precision(int value) {
+    // This function exists as of libpcap version 1.5.0.
+    #ifdef HAVE_PCAP_TIMESTAMP_PRECISION
+    int result = pcap_set_tstamp_precision(get_pcap_handle(), value);
+    if (result == PCAP_ERROR_TSTAMP_PRECISION_NOTSUP) {
+        throw pcap_error("Timestamp precision not supported");
+    }
+    #endif // HAVE_PCAP_TIMESTAMP_PRECISION
+}
+
 void Sniffer::set_rfmon(bool rfmon_enabled) {
     #ifndef _WIN32
     if (pcap_can_set_rfmon(get_pcap_handle()) == 1) {
@@ -408,7 +418,8 @@ const unsigned SnifferConfiguration::DEFAULT_TIMEOUT = 1000;
 
 SnifferConfiguration::SnifferConfiguration()
 : flags_(0), snap_len_(DEFAULT_SNAP_LEN), buffer_size_(0), timeout_(DEFAULT_TIMEOUT),
-  promisc_(false), rfmon_(false), immediate_mode_(false), direction_(PCAP_D_INOUT) {
+  promisc_(false), rfmon_(false), immediate_mode_(false), direction_(PCAP_D_INOUT),
+  timestamp_precision_(0) {
 
 }
 
@@ -427,6 +438,9 @@ void SnifferConfiguration::configure_sniffer_pre_activation(Sniffer& sniffer) co
     if ((flags_ & IMMEDIATE_MODE) != 0) {
         sniffer.set_immediate_mode(immediate_mode_);
     }
+    if ((flags_ & TIMESTAMP_PRECISION) != 0) {
+        sniffer.set_timestamp_precision(timestamp_precision_);
+    }
 }
 
 void SnifferConfiguration::configure_sniffer_pre_activation(FileSniffer& sniffer) const {
@@ -486,6 +500,11 @@ void SnifferConfiguration::set_immediate_mode(bool enabled) {
     immediate_mode_ = enabled;
 }
 
+void SnifferConfiguration::set_timestamp_precision(int value) {
+    flags_ |= TIMESTAMP_PRECISION;
+    timestamp_precision_ = value;
+}
+
 void SnifferConfiguration::set_direction(pcap_direction_t direction) {
     direction_ =  direction;
     flags_ |= DIRECTION;