UDP 套接字设置超时 [英] UDP Socket Set Timeout

问题描述

我正在尝试在 UDP 套接字上设置 100 毫秒超时.我正在使用 C.我在下面发布了我的代码的相关部分.我不确定为什么这不是超时，而是在它没有收到一个段时挂起.这是否仅适用于未使用 bind() 方法绑定的套接字?

I am trying to set a 100ms timeout on a UDP Socket. I am using C. I have posted relavent pieces of my code below. I am not sure why this is not timing out, but just hangs when it doesn't receive a segment. Does this only work on sockets that are not bound using the bind() method?

#define TIMEOUT_MS      100     /* Seconds between retransmits */

if ((rcv_sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
    DieWithError("socket() failed");

if ((rcv_sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
    DieWithError("socket() failed");

//set timer for recv_socket
static int timeout = TIMEOUT_MS;
setsockopt(rcv_sock, SOL_SOCKET, SO_RCVTIMEO,(char*)&timeout,sizeof(timeout));

if(recvfrom(rcv_sock, ackBuffer,sizeof(ackBuffer), 0,
       (struct sockaddr *) &servAddr2, &fromSize) < 0){
    //timeout reached
    printf("Timout reached. Resending segment %d
", seq_num);
    num_timeouts++;
}

推荐答案

SO_RCVTIMEO 选项需要 sys/time.h 中定义的 struct timeval代码>，而不是像您传递给它的整数.timeval struct 具有用于秒的字段和用于微秒的字段.要将超时设置为 100 毫秒，以下应该可以解决问题:

The SO_RCVTIMEO option expects a struct timeval defined in sys/time.h, not an integer like you're passing to it. The timeval struct has as field for seconds and a field for microseconds. To set the timeout to 100ms, the following should do the trick:

struct timeval tv;
tv.tv_sec = 0;
tv.tv_usec = 100000;
if (setsockopt(rcv_sock, SOL_SOCKET, SO_RCVTIMEO,&tv,sizeof(tv)) < 0) {
    perror("Error");
}

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