Added get_fd() to BaseSniffer.

Signed-off-by: Matias Fontanini <matias.fontanini@gmail.com>

include/sniffer.h

@@ -159,6 +159,11 @@ namespace Tins {
          * \brief Stops sniffing loops.
          */
         void stop_sniff();
+
+        /**
+         * \brief Gets the file descriptor associated with the sniffer.
+         */
+        int get_fd();
     protected:
         /**
          * Default constructor.

src/sniffer.cpp

@@ -105,6 +105,10 @@ void BaseSniffer::stop_sniff() {
     pcap_breakloop(handle);
 }
 
+int BaseSniffer::get_fd() {
+    return pcap_get_selectable_fd(handle);
+}
+
 bool BaseSniffer::set_filter(const std::string &filter) {
     if(actual_filter.bf_insns)
         pcap_freecode(&actual_filter);