读取 Windows UDP 缓冲区大小

Question

我发现很难弄清楚如何通过命令提示符检查 Windows 中的 UDP 缓冲区大小。我正在寻找类似于 linux 命令“sysctl net.core.rmem_max”的东西。我不需要设置 UDP 缓冲区大小，我只需要检查它以便在它小于我推荐的大小时发出警告。到目前为止，我似乎在每个地方都指向通过 Windows 注册表设置缓冲区大小。有谁知道通过命令提示符或 C++ 简单地检查缓冲区大小的可能方法吗？

Answer 1

我不知道如何从命令行执行此操作（看起来 PowerShell 可以做到），但您应该能够按如下方式在 C++ 中执行此操作（注意：未经测试）：

#include <iostream>
#include <WinSock2.h>
#include <Ws2tcpip.h>
#pragma comment (lib, "Ws2_32.lib")

int main ()
{
    WSADATA wsaData;
    int err = WSAStartup (MAKEWORD (2, 2), &wsaData);
    if (err != NO_ERROR)
    {
        std::cerr << "WSAStartup failed with error " << err << "\n";
        return 1;
    }

    SOCKET s = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (s == INVALID_SOCKET)
    {
        std::cerr << "socket failed with error " << WSAGetLastError () << "\n"
        return 1;
    }

    int rcvbuf_len;
    socklen_t optlen = sizeof (rcvbuf_len);

    if (getsockopt (s, SOL_SOCKET, SO_RCVBUF, &rcvbuf_len, &optlen) < 0)
    {
        std::cerr << "getsockopt failed with error " << WSAGetLastError () << "\n";
        return 1;
    }

    std::cout << "UDP receive buffer length = " << rcvbuf_len << " bytes\n");
}

我们不需要在这里清理任何资源，因为程序退出时会自动清理。

Answer 2

我使用了@Paul Sanders的代码，并根据getsockopt函数和socket函数的官方文档（可以找到here for getsockopt and here for socket）添加了一些修改，修正了一些小问题详细信息并将其编译为

g++ get_buff_size.cpp -o get_buff_size.exe -lwsock32

我用它仔细检查了 MS 文档中关于 DefaultReceiveWindow 参数的信息，并试图弄清楚 DefaultReceiveWindow 是否适用于 TCP 和 UDP。

这是对我有用的代码：

#include <iostream>
#include <WinSock2.h>
#include <Ws2tcpip.h>

int main()
{
    int optVal;
    int optLen = sizeof(int);

    WSADATA wsaData;
    int err = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (err != NO_ERROR)
    {
        printf("WSAStartup failed with error %d\n", err);
        return 1;
    }

    SOCKET listenSocketTCP = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if (listenSocketTCP == INVALID_SOCKET)
    {
        printf("socket failed with error %d\n", WSAGetLastError());
        return 1;
    }

    SOCKET listenSocketUDP = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (listenSocketUDP == INVALID_SOCKET)
    {
        printf("socket failed with error %d\n", WSAGetLastError());
        return 1;
    }

    if (getsockopt(listenSocketTCP, SOL_SOCKET, SO_RCVBUF, (char *)&optVal, &optLen) != SOCKET_ERROR)
    {
        printf("TCP SO_RCVBUF Value: %d\n", optVal);
    }
    else
    {
        printf("TCP SO_RCVBUF getsockopt failed with error %d\n", WSAGetLastError());
        return 1;
    }

    if (getsockopt(listenSocketTCP, SOL_SOCKET, SO_SNDBUF, (char *)&optVal, &optLen) != SOCKET_ERROR)
    {
        printf("TCP SO_SNDBUF Value: %d\n", optVal);
    }
    else
    {
        printf("TCP SO_SNDBUF getsockopt failed with error %d\n", WSAGetLastError());
        return 1;
    }

    if (getsockopt(listenSocketUDP, SOL_SOCKET, SO_RCVBUF, (char *)&optVal, &optLen) != SOCKET_ERROR)
    {
        printf("UDP SO_RCVBUF Value: %d\n", optVal);
    }
    else
    {
        printf("UDP SO_RCVBUF getsockopt failed with error %d\n", WSAGetLastError());
        return 1;
    }

    if (getsockopt(listenSocketUDP, SOL_SOCKET, SO_SNDBUF, (char *)&optVal, &optLen) != SOCKET_ERROR)
    {
        printf("UDP SO_SNDBUF Value: %d\n", optVal);
    }
    else
    {
        printf("UDP SO_SNDBUF getsockopt failed with error %d\n", WSAGetLastError());
        return 1;
    }

    return 0;
}

你应该期待这样的输出：

TCP SO_RCVBUF Value: 65536
TCP SO_SNDBUF Value: 65536
UDP SO_RCVBUF Value: 65536
UDP SO_SNDBUF Value: 65536

读取 Windows UDP 缓冲区大小

Read Windows UDP Buffer Size

c++

windows

udp

buffer

command-prompt