[Ccrtp-devel] IPv6 support in ccRTP

[Gabor Ivan]

Dear ccRTP developers,

I tried to use ccRTP over an IPv6 protocol stack. If I'm not mistaken,
the only main change (compared to IPv4) is that the class
"RTPSessionIPV6" has to be used instead of "RTPSession". I tried to
create an instance of the class "RTPSessionIPv6":

RTPSessionIPV6 * socket = new RTPSessionIPV6 (IPV6Host("localhost"), port);

and the compiler gave the following errors:

error: cannot allocate an object of abstract type 'ost::RTPSessionIPV6',
because the following virtual functions are pure within
'ost::RTPSessionIPV6':
/usr/include/ccrtp/oqueue.h: virtual void
ost::OutgoingDataQueue::setControlPeer (const ost::IPV4Address&,
ost::tpport_t)
/usr/include/ccrtp/oqueue.h: virtual void
ost::OutgoingDataQueue::setDataPeer (const ost::IPV4Address&, ost::tpport_t)
/usr/include/ccrtp/iqueue.h: virtual void
ost::IncomingDataQueue::recvData (unsigned char *, size_t, const
ost::IPV4Address&, ost::tpport_t&)
/usr/include/ccrtp/cqueue.h: virtual void
ost::QueueRTCPManager::recvControl (unsigned char *, size_t,
ost::IPV4Address&, ost::tpport_t&)

The functions mentioned above are pure virtual functions, making e.g.
the class "OutgoingDataQueue" an abstract class, which cannot be
instantiated. As RTPSessionIPV6 does not implement these fucntions
either, it also becomes an abstract class.

So, the problem is that RTPSessionIPV6 does not implement the functions
mentioned above; instead it implements _almost_ the same functions, but
with "IPV6Host&"-type addresses (and not "IPV4Address&"). Unfortunately
these count as a whole new function in C++, so I assume this to be the
cause of the errors.

The solution could probably be to append the class "RTPSessionIPV6" with
a "fake implementation" of the above mentioned functions, _and_ also
adding the already implemented functions from "RTPSessionIPv6" (which
get the IP address in an  "IPV6Host"-type parameter) as a virtual
function of the classes "OutgoingDataQueue", "IncomingDataQueue",
"QueueRTCPManager".

Sure that mine is not a very nice solution, and, as I'm not quite
familiar with ccRTP yet, it could possibly not work. That's why I'm
asking Your advice: do you consider this a real bug in ccRTP library? If
yes, what solution would You suggest? How is it possible to use ccRTP 
over an IPv6-based protocol stack?

Thanks,

Gabor Ivan