Destructor for a packet?

[Daniel Friedman <danielf@isr.umd.edu>]

I have created a packet header which looks something like this:

struct hdr_mypkt {
	// ...
	char *mydata;
	// ...
}

...and I dynamically allocate memory (using "new") for "mydata" to point
to.  (This way I can change the length of a field in the packet.) The
problem I have is that if I send such a packet through a link, and this
packet overflows in the queue of the link, [it at least seems that] the
memory dynamically allocated earlier is not freed.

Hence I think I need something like a destructor for this packet, which
will free the memory. But how does one make a destructor, since custom
packet types are not themselves classes in NS?

Or, if my approach is incorrect--either 1) in making a variable-length
packet field, or in 2) freeing the memory of a dynamically-allocated
field if the packet is dropped by queue overflow--, what should I be
doing?

Many thanks for all suggestions!!
--daniel

---------------------------------------------------------------------------
 Daniel Friedman    danielf@isr.umd.edu    http://www.isr.umd.edu/~danielf