c - setsockopt() 中的错误 : Numerical argument out of domain

我有一个在 RedHat 安装的 Linux 上运行的工作代码，内核为 2.6.18-194.el5 #1 SMP x86_64 。

当我将代码移动到新安装的 CentOS 6.3 机器时，相同的代码失败了



后者机器的内核版本是 2.6.32-279.el6.x86_64 #1 SMP

下面分别是机器中工作和失败的代码。

    struct timeval          tv;

    tv.tv_sec       = 0;
    tv.tv_usec      = 1500000;

    if (setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(struct timeval)) != 0)
    {
            LM_ERR("Error assigning socket option: %s", strerror( errno ));
            return FALSE;
    }

最佳答案

尝试使用

tv.tv_sec       = 1;
tv.tv_usec      = 500000;

我已经看到一些实现不接受 10^6 以上的 tv_usec。

编辑: 这个问题很有趣，可以稍微挖掘一下。在内核源代码中寻找 SO_RCVTIMEO 我在 net/core/sock.c 中找到了以下代码:

int sock_setsockopt(struct socket *sock, int level, int optname,
            char __user *optval, unsigned int optlen)
{

   / ... /
   switch (optname) {

   / ... /

   case SO_RCVTIMEO:
        ret = sock_set_timeout(&sk->sk_rcvtimeo, optval, optlen);
        break;

   / ... /
}

sock_set_timeout() 函数的开头确实包含了一些范围检查:

static int sock_set_timeout(long *timeo_p, char __user *optval, int optlen)
{
    struct timeval tv;

    if (optlen < sizeof(tv))
        return -EINVAL;
    if (copy_from_user(&tv, optval, sizeof(tv)))
        return -EFAULT;
    if (tv.tv_usec < 0 || tv.tv_usec >= USEC_PER_SEC)
        return -EDOM;

    /* ... */
}

现在我们知道足够做一些 git blame -ing :) 更改是通过以下更改集引入的:

commit ba78073e6f70cd9c64a478a9bd901d7c8736cfbc
Author: Vasily Averin <[email protected]>
Date:   Thu May 24 16:58:54 2007 -0700

[NET]: "wrong timeout value" in sk_wait_data() v2

sys_setsockopt() do not check properly timeout values for
SO_RCVTIMEO/SO_SNDTIMEO, for example it's possible to set negative timeout
values. POSIX do not defines behaviour for sys_setsockopt in case negative
timeouts, but requires that setsockopt() shall fail with -EDOM if the send and
receive timeout values are too big to fit into the timeout fields in the socket
structure.
In current implementation negative timeout can lead to error messages like
"schedule_timeout: wrong timeout value".

Proposed patch:
- checks tv_usec and returns -EDOM if it is wrong
- do not allows to set negative timeout values (sets 0 instead) and outputs
  ratelimited information message about such attempts.

Signed-off-By: Vasily Averin <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

我相信提交评论解释了一切。据我所知，此更改包含在 2.6.22-rc3 中。

关于c - setsockopt() 中的错误 : Numerical argument out of domain，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/13886761/