场景:我有一个简单的程序,可以通过Linux p2p-wlan0-0
上的bcast接口广播一些消息。以下是程序。
代码:
#include <boost/asio.hpp>
#include <boost/system/error_code.hpp>
#include <iostream>
#include <memory>
#include <string>
#include <thread>
boost::asio::io_service ioService;
boost::asio::ip::udp::socket udpSocket = boost::asio::ip::udp::socket(ioService);
boost::asio::ip::udp::endpoint endPoint;
void Prepare() {
const int port = 36512; // Some port
const std::string& broadcastIPAddress = "192.168.1.1";
udpSocket.open(boost::asio::ip::udp::v4());
udpSocket.set_option(boost::asio::socket_base::reuse_address(true));
udpSocket.set_option(boost::asio::socket_base::broadcast(true));
boost::asio::ip::address_v4 address = boost::asio::ip::address_v4::from_string(broadcastIPAddress);
boost::asio::ip::address_v4 broadcastAddressV4 = boost::asio::ip::address_v4::broadcast(address,
boost::asio::ip::address_v4::from_string("255.255.255.0")) ;
endPoint = boost::asio::ip::udp::endpoint(broadcastAddressV4, port);
boost::asio::ip::address interfaceIPAddress(boost::asio::ip::address_v4::from_string(broadcastIPAddress));
boost::system::error_code ec;
udpSocket.set_option(boost::asio::ip::multicast::outbound_interface(interfaceIPAddress.to_v4()), ec);
}
void Broadcast(const std::string& messageToBroadcast) {
boost::system::error_code ec;
udpSocket.send_to(boost::asio::buffer(messageToBroadcast.c_str(), messageToBroadcast.length()), endPoint, 0, ec);
std::cout << "Broadcasted udp message " << messageToBroadcast << std::endl;
}
int main() {
std::cout << "Program starts" << std::endl;
std::atomic<bool> stopped{false};
std::thread t([&stopped](){
std::cout << "Broadcasting thread starting up" << std::endl;
Prepare();
do {
Broadcast("hello");
std::this_thread::sleep_for(std::chrono::seconds(1));
} while(!stopped.load());
});
std::this_thread::sleep_for(std::chrono::minutes(1));
stopped.store(true);
t.join();
std::cout << "Program ends" << std::endl;
}
接收器是一个盲目接收数据的接收循环。而且整个过程都有效。我能够发送和接收数据包。
问题:但是,我在广播接口上丢失了很多数据包。就像十分之一的数据包一样。我很惊讶,因为它是p2p连接。我需要进行10次广播,才能在接收器一侧收到一个广播。真奇怪!这是它应该如何工作的本质吗? UDP广播是否如此不可靠?还是我在设置UDP套接字的方式上发生了错误?
尽管设置了广播套接字选项,但192.168.1.1
不是广播地址,而是单播地址。
尝试使用广播地址192.168.1.255
或255.255.255.255
。