boost :: asio verbindet falsche Schnittstelle

Question

Ich habe ein Dual-Multicast-Setup, bei dem jede Multicast-Gruppe eine Verbindung zu einer bestimmten Schnittstelle auf meinem Server herstellen muss.

Coliru

#include <boost/asio.hpp> 
#include <iostream> 

namespace ip = boost::asio::ip; 
using ip::udp; 

boost::asio::io_service io; 

struct Connection { 
    int32_t timeout = 5000; 
    udp::socket sock {io}; 
    ip::address addr; 

    bool Connect(std::string const& localAddr, std::string const& addrStr, int port, boost::system::error_code& ec) { 
     // Multicast socket 
     udp::endpoint local(ip::address::from_string(localAddr), port); // leaving host/port unbound doesn't seem to help 

     std::cout << "Using local " << local << "\n"; 
     addr = ip::address::from_string(addrStr); 
     udp::endpoint multicastEndpoint(addr, port); 

     sock.open(multicastEndpoint.protocol()); 
     // The commented flags don't seem to have any effect on the findings 
     //sock.set_option(ip::multicast::enable_loopback()); 
     sock.bind(local, ec); 
     sock.set_option(ip::multicast::join_group(addr.to_v4())); 
     sock.set_option(udp::socket::reuse_address(true)); 
     //setsockopt(sock.native(), SOL_SOCKET, SO_RCVTIMEO, (const char *)&timeout, sizeof(timeout)); 

     return ec? false : true; 
    } 
}; 

struct ConnectionPair { 
    Connection a, b; 

    bool Connect(std::string const& addrStrA, int portA, std::string const& addrStrB, int portB, boost::system::error_code& ec) { 
     // Example adresses; Replace with your local adapter addresses 
     return a.Connect("172.17.0.1",  addrStrA, portA, ec) 
      && b.Connect("192.168.195.62", addrStrB, portB, ec); 
    } 
}; 

int main() { 
    try { 
     ConnectionPair pair; 
     boost::system::error_code ec; 

     // all hosts multicast groups 
     if (pair.Connect("224.0.0.251", 5656, "224.0.0.1", 5657, ec)) { 
      std::cout << "Both connected... "; 
      boost::asio::deadline_timer dlt(io, boost::posix_time::seconds(5)); 
      dlt.wait(); 
     } else { 
      std::cout << "Connection error: " << ec.message() << "\n"; 
     } 
    } catch(std::exception const& e) { 
     std::cout << "Exception: '" << e.what() << "'\n"; 
    } 
    std::cout << "Bye\n"; 
} 

Problem ist, wenn diese mit verbinden, wird Socket A keine Daten zu bekommen. Unter Verwendung von netsh interface ip show join zeigt es, dass beide Multicast-Gruppen in der Schnittstelle, die localAddrB entspricht, anstelle von jeder an ihrer Stelle verbunden wurden.

Wenn Sie mdump verwenden, um den Multicast-Gruppen beizutreten, verbindet sich jede mit der richtigen Position und empfängt Daten.

Ich kann nicht herausfinden, wo ich mit meinem Code falsch gelaufen bin.

Answer 1

Sie können die Schnittstelle angeben, an der die Multicast-Gruppe gesendet/verbunden werden soll.

http://www.boost.org/doc/libs/1_47_0/boost/asio/ip/detail/socket_option.hpp

Diese zwei Linien:

this->socket.set_option(ip::multicast::outbound_interface(ip::address_v4::from_string(this->address))); 

this->socket.set_option(ip::multicast::join_group(joinAddress, listenInterface)); 

Im Kontext:

• Server-Code:

  this->socket.open(ip::udp::v4()); 
  this->socket.set_option(ip::udp::socket::reuse_address(true)); 
  this->socket.set_option(ip::multicast::enable_loopback(true)); 
  this->socket.set_option(ip::multicast::hops(HOPS)); 
  
  this->socket.set_option(ip::multicast::outbound_interface(ip::address_v4::from_string(this->address))); 
  this->socket.bind(ip::udp::endpoint(ip::address_v4::from_string(this->address), 0)); // any port 
  
  this->ioService.run(); // blocking 
  

• -Client-Code :

  udp::endpoint bindEndpoint(ip::address_v4::any(), UDPMulticastServer::PORT); 
  this->socket.open(ip::udp::v4()); 
  this->socket.set_option(ip::udp::socket::reuse_address(true)); 
  this->socket.bind(bindEndpoint); 
  
  // Join the multicast group on a specific interface 
  ip::address_v4 joinAddress = ip::address_v4::from_string(UDPMulticastServer::MULTICAST_ADDRESS); 
  ip::address_v4 listenInterface = ip::address_v4::from_string(this->address); 
  this->socket.set_option(ip::multicast::join_group(joinAddress, listenInterface)); 
  
  this->listenForBroadcast(); 
  this->ioService.run(); // blocking