c++ - 充当多播服务器和客户端的 Linux 套接字

Question

我在同一进程中使用了两个套接字，一个充当多播服务器，另一个充当多播客户端。我正在尝试将服务器和客户端功能结合在一个套接字中。到现在还不能成功。是否有人尝试将单个套接字作为多播服务器和客户端。是否可以？如果没有任何说明限制的引用，我们将不胜感激。非常感谢。

Answer 1

至少在 Windows 上是可能的。尝试以下示例(不检查错误):

SOCKET the_socket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);

sockaddr_in service;
service.sin_family = AF_INET;
service.sin_addr.s_addr = inet_addr("192.168.1.117");
service.sin_port = htons(56565);

int ret = bind(the_socket, (SOCKADDR *) &service, sizeof (service));

unsigned int grpaddr = inet_addr("224.4.4.44");
unsigned int iaddr = inet_addr("192.168.1.117");

//You should have the equivalent function in your existing client 
//to join the multicast group
ret = join_source_group(the_socket, grpaddr, service.sin_addr.s_addr, iaddr);

std::string data = "AA";

sockaddr_in group;
group.sin_family = AF_INET;
group.sin_addr.s_addr = inet_addr("224.4.4.44");
group.sin_port = htons(56565);

ret = sendto(the_socket, data.c_str(), data.length(), 0, (const sockaddr*)&group, sizeof(group));

char recvdata[3] = {0};
ret = recv(the_socket, recvdata, 3, 0);

leave_source_group(the_socket, grpaddr, service.sin_addr.s_addr, iaddr);