c++ - How to use miniupnpc with Boost.Asio UDP when binding a socket to a random port -

i'm astonished lack of documentation on miniupnp, believe there's lot of people using it, no documentation @ all, found piece of code in source of raknet guide me.

now i'm having conceptual issue...

i'm developing app connects server via udp (the server should accessible, server udp port specific 1 open, , can test using open port checker), server puts 2 or more clients talking each other (p2p), need circumvent nat in clients work.

i have nat punch through working, , solves lots of cases.

now, want add upnp functionality, attack nat issue too.

i'm using miniupnpc, , handle connections boost.asio.

struct upnpdev * devlist = 0; devlist = upnpdiscover(2000, 0, 0, 0, 0, 0); if (devlist) {     std::cout << "\nlist of upnp devices found on network :\n";      struct upnpdev * device;     for(device = devlist; device; device = device->pnext) {         std::cout << "\ndesc: " << device->descurl << "\n st: " << device->st << "\n";     }      char lanaddr[64];   /* ip address on lan */     struct upnpurls urls;     struct igddatas data;     if (upnp_getvalidigd(devlist, &urls, &data, lanaddr, sizeof(lanaddr)) == 1) {         string port = lexical_cast<string>(socket->local_endpoint().port());          int r = upnp_addportmapping(urls.controlurl, data.first.servicetype,             port.c_str(), port.c_str(), lanaddr, 0, "udp", 0, "0");          if (r != upnpcommand_success) {             std::cout << "\nupnp fail";         }          char intport[6];         char intclient[16];          char desc[128];         char enabled[128];         char leaseduration[128];         r = upnp_getspecificportmappingentry(urls.controlurl,             data.first.servicetype,             port.c_str(), "udp", 0,             intclient, intport,             desc, enabled, leaseduration);          if (r != upnpcommand_success) {             std::cout << "\nupnp fail";         }else {             std::cout << "\nupnp success on port " << port;         }     } } 

as can see, execute upnp after having bound socket (i bind without specific port, this:)

asio::udp::socket socket(*this->ioservice, asio::udp::endpoint()); 

my question is, upnp execution makes sense? socket use upnp port map if execute upnp on random port bound socket after bind it?

thanks guys!