int Network::tcp4Listen(bi::tcp::acceptor& _acceptor, NetworkPreferences const& _netPrefs)
{
// Due to the complexities of NAT and network environments (multiple NICs, tunnels, etc)
// and security concerns automation is the enemy of network configuration.
// If a preference cannot be accommodate the network must fail to start.
//
// Preferred IP: Attempt if set, else, try 0.0.0.0 (all interfaces)
// Preferred Port: Attempt if set, else, try c_defaultListenPort or 0 (random)
// TODO: throw instead of returning -1 and rename NetworkPreferences to NetworkConfig
bi::address listenIP;
try
{
listenIP = _netPrefs.listenIPAddress.empty() ? bi::address_v4() : bi::address::from_string(_netPrefs.listenIPAddress);
}
catch (...)
{
LOG(WARNING) << "Couldn't start accepting connections on host. Failed to accept socket on " << listenIP << ":" << _netPrefs.listenPort << ".\n" << boost::current_exception_diagnostic_information();
return -1;
}
bool requirePort = (bool)_netPrefs.listenPort;
for (unsigned i = 0; i < 2; ++i)
{
bi::tcp::endpoint endpoint(listenIP, requirePort ? _netPrefs.listenPort : (i ? 0 : c_defaultListenPort));
try
{
#if defined(_WIN32)
bool reuse = false;
#else
bool reuse = true;
#endif
_acceptor.open(endpoint.protocol());
_acceptor.set_option(ba::socket_base::reuse_address(reuse));
_acceptor.bind(endpoint);
_acceptor.listen();
return _acceptor.local_endpoint().port();
}
catch (...)
{
// bail if this is first attempt && port was specificed, or second attempt failed (random port)
if (i || requirePort)
{
// both attempts failed
LOG(WARNING) << "Couldn't start accepting connections on host. Failed to accept socket on " << listenIP << ":" << _netPrefs.listenPort << ".\n" << boost::current_exception_diagnostic_information();
_acceptor.close();
return -1;
}
_acceptor.close();
continue;
}
}
return -1;
}
int Network::tcp4Listen(bi::tcp::acceptor& _acceptor, NetworkPreferences const& _netPrefs)
{
int retport = -1;
if (_netPrefs.listenIPAddress.empty())
for (unsigned i = 0; i < 2; ++i)
{
// try to connect w/listenPort, else attempt net-allocated port
bi::tcp::endpoint endpoint(bi::tcp::v4(), i ? 0 : _netPrefs.listenPort);
try
{
_acceptor.open(endpoint.protocol());
_acceptor.set_option(ba::socket_base::reuse_address(true));
_acceptor.bind(endpoint);
_acceptor.listen();
retport = _acceptor.local_endpoint().port();
break;
}
catch (...)
{
if (i)
{
// both attempts failed
cwarn << "Couldn't start accepting connections on host. Something very wrong with network?\n" << boost::current_exception_diagnostic_information();
}
// first attempt failed
_acceptor.close();
continue;
}
}
else
{
bi::tcp::endpoint endpoint(bi::address::from_string(_netPrefs.listenIPAddress), _netPrefs.listenPort);
try
{
_acceptor.open(endpoint.protocol());
_acceptor.set_option(ba::socket_base::reuse_address(true));
_acceptor.bind(endpoint);
_acceptor.listen();
retport = _acceptor.local_endpoint().port();
assert(retport == _netPrefs.listenPort);
}
catch (...)
{
clog(NetWarn) << "Couldn't start accepting connections on host. Failed to accept socket.\n" << boost::current_exception_diagnostic_information();
}
return retport;
}
return retport;
}
