Allow asking whether segment was acked

include/tins/tcp_ip/ack_tracker.h

@@ -129,6 +129,14 @@ public:
      * \brief Retrieves all acked intervals by Selective ACKs
      */
     const interval_set_type& acked_intervals() const; 
+
+    /**
+     * \brief Indicates whether the given segment has been already ACKed
+     *
+     * \param sequence_number The segment's sequence number
+     * \param length The segment's length
+     */
+    bool is_segment_acked(uint32_t sequence_number, uint32_t length) const;
 private:
     void process_sack(const std::vector<uint32_t>& sack);
     void cleanup_sacked_intervals(uint32_t old_ack, uint32_t new_ack);

include/tins/tcp_ip/flow.h

@@ -282,6 +282,18 @@ public:
      * \brief Indicates whether ACK number tracking is enabled
      */
     bool ack_tracking_enabled() const;
+
+    #ifdef HAVE_ACK_TRACKER
+    /**
+     * Retrieves the ACK tracker for this Flow (const)
+     */
+    const AckTracker& ack_tracker() const;
+
+    /**
+     * Retrieves the ACK tracker for this Flow
+     */
+    AckTracker& ack_tracker();
+    #endif // HAVE_ACK_TRACKER
 private:
     // Compress all flags into just one struct using bitfields 
     struct flags {