add advertised_size method

Author: pepper-jk

include/tins/ip.h

@@ -281,6 +281,10 @@ class TINS_API IP : public PDU {
 
     /* Getters */
 
+    uint32_t advertised_size() const {
+        return static_cast<uint32_t>(tot_len());
+    }
+
     /**
      * \brief Getter for the header length field.
      *

include/tins/pdu.h

@@ -281,6 +281,12 @@ class TINS_API PDU {
      */
     uint32_t size() const;
 
+    /** \brief The whole chain of PDU's advertised size, including this one.
+     *
+     * Returns the sum of this and all children PDU's advertised size.
+     */
+    virtual uint32_t advertised_size() const;
+
     /**
      * \brief Getter for the inner PDU.
      * \return The current inner PDU. Might be a null pointer.

src/pdu.cpp

@@ -85,6 +85,10 @@ uint32_t PDU::size() const {
     return sz;
 }
 
+uint32_t PDU::advertised_size() const {
+    return header_size() + trailer_size() + inner_pdu()->advertised_size();
+}
+
 void PDU::send(PacketSender &, const NetworkInterface &) { 
 
 }