我正在编写一个实现基于UDP的协议的库。
我是A主机,远程主机是B。
我需要从A主机的7011端口发送消息到B主机的7011端口。然后B主机将回复A主机的7011端口。通信是异步的,因此我需要监听传入消息的udp,有时还需要从服务器绑定的同一端口发送消息。
以下是我创建和绑定套接字的方式:
以下是我创建和绑定套接字的方式:
udp_server::udp_server(const std::string &localAddress, int localPort)
: f_port(localPort), f_addr(localAddress) {
char decimal_port[16];
snprintf(decimal_port, sizeof(decimal_port), "%d", f_port);
decimal_port[sizeof(decimal_port) / sizeof(decimal_port[0]) - 1] = '\0';
struct addrinfo hints;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_protocol = IPPROTO_UDP;
int r(getaddrinfo(localAddress.c_str(), decimal_port, &hints, &f_addrinfo));
if (r != 0 || f_addrinfo == NULL) {
throw udp_client_server_runtime_error(
("invalid address or port for UDP socket: \"" + localAddress + ":" + decimal_port + "\"").c_str());
}
f_socket = socket(f_addrinfo->ai_family, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP);
if (f_socket == -1) {
freeaddrinfo(f_addrinfo);
throw udp_client_server_runtime_error(
("could not create UDP socket for: \"" + localAddress + ":" + decimal_port + "\"").c_str());
}
r = bind(f_socket, f_addrinfo->ai_addr, f_addrinfo->ai_addrlen);
if (r != 0) {
freeaddrinfo(f_addrinfo);
close(f_socket);
throw udp_client_server_runtime_error(
("could not bind UDP socket with: \"" + localAddress + ":" + decimal_port + "\"").c_str());
}
}
这里我正在尝试发送消息:
ssize_t udp_server::sendto(std::string remoteHost, uint16_t port, const char *message, size_t messageLength) {
struct sockaddr_in remote;
remote.sin_family = AF_INET;
remote.sin_port = htons(7011);
remote.sin_addr.s_addr = ::inet_addr("10.8.0.6");
socklen_t addrSize;
addrSize = sizeof(remote);
memset(remote.sin_zero, '\0', sizeof(remote.sin_zero));
dout << "messageLength: " << messageLength << std::endl;
return ::sendto(this->f_socket, message, messageLength, 0, (struct sockaddr *)&remote, addrSize);
}
但是 ::sendto 总是返回 -1。并且 errno 被设置为 22,这意味着无效参数。可能的解决方案是什么?也许整体结构不好。
=== 解决方案 === 我将我的服务器绑定到了本地主机 :( 应该是 0.0.0.0 或 INADDR_ANY。
udp_server::udp_server
和server::sendto
的? - dbushthis->server = make_unique<udp_server>('localhost', localControlPort);
and thenthis->server->sendto(this->remoteHost, this->controlPort, (const char *)(buffer), static_cast<size_t>(length));
- victor_crimea