make_socket_udp_recv.hpp

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#ifndef jb_itch5_make_socket_udp_recv_hpp
#define jb_itch5_make_socket_udp_recv_hpp

#include <jb/itch5/make_socket_udp_common.hpp>
#include <jb/itch5/udp_receiver_config.hpp>

#include <boost/asio/ip/multicast.hpp>
#include <boost/asio/ip/udp.hpp>

#include <string>

namespace jb {
namespace itch5 {

namespace detail {
/// Configure a socket to receive UDP packets
template <class socket_t>
void setup_socket_udp_recv(socket_t& socket, udp_receiver_config const& cfg) {
  auto r_address = boost::asio::ip::address::from_string(cfg.address());

  boost::asio::ip::address local_address;

  // Automatically configure the best listening address ...
  if (cfg.local_address() != "") {
    // ... the user specified a listening address, use that ...
    local_address = boost::asio::ip::address::from_string(cfg.local_address());
  } else if (r_address.is_multicast()) {
    // ... pick a default based on the protocol for the listening
    // group ...
    if (r_address.is_v6()) {
      local_address = boost::asio::ip::address_v6();
    } else {
      local_address = boost::asio::ip::address_v4();
    }
  } else {
    // ... whatever the receive address is, it must be a unicast
    // address, use it as the local address of the socket.  Notice
    // that it can be ADDRANY, such as ::1 ...
    local_address = r_address;
  }

  // ... the rest if fairly mechanical stuff ..
  boost::asio::ip::udp::endpoint endpoint(local_address, cfg.port());
  socket.open(endpoint.protocol());
  socket.set_option(
      boost::asio::ip::udp::socket::reuse_address(cfg.reuse_address()));
  socket.bind(endpoint);
  if (r_address.is_multicast()) {
    socket.set_option(boost::asio::ip::multicast::join_group(r_address));
    socket.set_option(boost::asio::ip::multicast::enable_loopback(true));
  }
}
} // namespace detail

/**
 * Create a socket given the configuration parameters.
 *
 * This is a function to create (open) sockets to receive UDP
 * messages, either unicast or multicast and either IPv4 or IPv6.
 *
 * @tparam socket_t the type of socket to create.  The main reason to
 * change this type is for dependency injection during testing.
 *
 * @param io the Boost.ASIO io_service object that the socket is
 * managed by.
 *
 * @param cfg the configuration parameters for the socket.
 *
 */
template <class socket_t = boost::asio::ip::udp::socket>
socket_t make_socket_udp_recv(
    boost::asio::io_service& io, udp_receiver_config const& cfg) {
  socket_t socket(io);
  detail::setup_socket_udp_recv(socket, cfg);
  make_socket_udp_common(socket, cfg);
  return socket;
}

} // namespace itch5
} // namespace jb

#endif // jb_itch5_make_socket_udp_recv_hpp