1
我正在嘗試使用select()
爲UDP套接字傳輸創建超時。我想發送int
從client
到server
,等待300ms,如果我沒有收到ACK,請重新發送數據包。我不確定如何在超時時間內正確設置它。從我在線收集的內容以及我在課堂上收到的筆記中,應該在接收端使用select
。丟失數據包超時(UDP)
服務器上的客戶端來回發送數字1-100。我有一個單獨的router
模擬代碼,隨機丟棄數據包
下面是代碼我有用於客戶端側
int sent = 1;
int received = 1;
for (int i = 0; i < 100; i++)
{
string sent1 = to_string(sent);
char const *pchar = sent1.c_str();
if(!sendto(s, pchar, sizeof(pchar), 0, (struct sockaddr*) &sa_in, sizeof(sa_in)))
cout << "send NOT successful\n";
else
{
cout << "Client sent " << sent << endl;
sent++;
}
// receive
fd_set readfds; //fd_set is a type
FD_ZERO(&readfds); //initialize
FD_SET(s, &readfds); //put the socket in the set
if(!(outfds = select (1 , &readfds, NULL, NULL, & timeouts)))
break;
if (outfds == 1) //receive frame
{
if (!recvfrom(s, buffer2, sizeof(buffer2), 0, (struct sockaddr*) &client, &client_length))
cout << "receive NOT successful\n";
else
{
received = atoi(buffer2);
cout << "Client received " << received << endl;
received++;
}
}
}
的代碼是在接收側,除了它是在反向相同:第一接收,然後發送
我的代碼根本沒有利用超時。這基本上就是我想做的事:
send packet(N)
if (timeout)
resend packet(N)
else
send packet(N+1)
Udp表示*不可靠*數據報協議。它不會執行或重新發送。你必須自己實現。這裏的發送超時是將數據包推送到有線或網絡堆棧上丟棄它。 – kfsone