IOS boost asio connect from ipv6 network - ios

Question

I am trying to connect a dvr using boost asio library in ios. The application works fine in emulator with in ipv4 network. But when I submit the application on Appstore apple rejected the application as it's not work on ipv6 network. And I can see in the apple site that application should support ipv6 network. https://developer.apple.com/news/?id=05042016a
So I think the problem comes at the section where I am trying to connect to DVR using boost library, where the ip address of the DVR is pulled from DB(hard-coded) and below is the relevant part of the code.
boost::asio::io_service io_service_;
tcp::resolver::iterator endpoint_iter_;
tcp::resolver resolver_; //to healp resolving hostname and ip
stringstream strstream;//create a stringstream
strstream << port;//add number to the stream
endpoint_iter_ = resolver_.resolve(tcp::resolver::query(ip.c_str(),strstream.str()));
start_connect(endpoint_iter_);
// Start the deadline actor. You will note that we're not setting any
// particular deadline here. Instead, the connect and input actors will
// update the deadline prior to each asynchronous operation.
deadline_timer_.async_wait(boost::bind(&dvr_obj::check_deadline, this));
//starting thread for dvr connection
io_service_.reset();
thread_ = new boost::thread(boost::bind(&boost::asio::io_service::run, &io_service_));
start_connect method
void start_connect(tcp::resolver::iterator endpoint_iter)
{
try
{
if (endpoint_iter != tcp::resolver::iterator())
{
drill_debug_info("trying to connect %s \n",name.c_str());
// Set a deadline for the connect operation.
deadline_timer_.expires_from_now(boost::posix_time::seconds(10));
// Start the asynchronous connect operation.
socket_.async_connect(endpoint_iter->endpoint(),
boost::bind(&dvr_obj::handle_connect,
this, _1, endpoint_iter));
}
else
{
// There are no more endpoints to try. Shut down the client.
connectivity = false;
}
} catch (int e) {
connectivity = false;
}
}
So I am confused how to change above code to work on IPV6 network. Could not find any solution in Internet.

Answer 1

You can iterate through the endpoints to find an IPv6 endpoint using the code below:
endpoint_iter_ = resolver_.resolve(tcp::resolver::query(ip.c_str(),strstream.str()));
while (endpoint_iter_ != tcp::resolver::iterator())
{
if (endpoint_iter_->endpoint().protocol() == tcp::v6())
break;
++endpoint_iter_;
}
if (endpoint_iter_ != tcp::resolver::iterator())
{
start_connect(endpoint_iter_);
...
}
else
std::cerr << "IPv6 host not found" << std::endl;