我有一个双组播设置,其中每个组播组都需要连接到我服务器上的特定接口(interface)。
#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";
}
问题是,当使用它进行连接时,套接字 A 没有获取任何数据。使用netsh interface ip show join
,显示两个多播组都已加入到localAddrB
对应的接口(interface)中,而不是各自在各自的位置。
当使用mdump
加入多播组时,每个组都连接到正确的位置并接收数据。
我不知道我的代码哪里出了问题。
最佳答案
您可以指定广播/加入多播组的接口(interface)。
http://www.boost.org/doc/libs/1_47_0/boost/asio/ip/detail/socket_option.hpp
这两行:
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));
在上下文中:
服务器代码:
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
客户代码:
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
关于c++ - boost::asio 加入了错误的接口(interface),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/43783236/