win7系统级socket缓冲区有多大？
本帖最后由 seeyou_shj 于 2020-1-8 15:36 编辑进行网络程序极限测试时发现，通过调用socket发送/接收数据，有时候会有接收到的数据包里面的数据部分丢失的情况，应该是系统默认的socket缓冲区太小导致。网上搜了一下如何设置系统默认的缓冲区大小设置，找到一些资料，比如
[*][HKEY_LOCAL_MACHINE \SYSTEM \CurrentControlSet\Services\Afd\Parameters]
[*]
[*]DefaultReceiveWindow = 1800 (16进制)
[*]DefaultSendWindow = 1800（16进制）
[*]可以设置Windows7修改socket默认缓冲区大小。
有个问题，不对其进行设置的情况下，默认的系统缓冲区有多大呢？是不是跟电脑内存有关？也就是说内存越大，系统默认的socket缓冲区越大？请大佬帮忙解惑，多谢！ 可以调用getsockopt函数设置SO_RCVBUF来获取 从MSDN官方网站找了个程序，测试了一下，结果返回0.
代码如下：
#include <stdio.h>
#include <winsock2.h>
#include <windows.h>
int main() {
//---------------------------------------
// Declare variables
WSADATA wsaData;
SOCKET ListenSocket;
sockaddr_in service;
//---------------------------------------
// Initialize Winsock
int iResult = WSAStartup( MAKEWORD(2,2), &wsaData );
if( iResult != NO_ERROR )
printf("Error at WSAStartup\n");
//---------------------------------------
// Create a listening socket
ListenSocket = socket( AF_INET, SOCK_STREAM, IPPROTO_TCP );
if (ListenSocket == INVALID_SOCKET) {
printf("Error at socket()\n");
WSACleanup();
return 0;
}
//---------------------------------------
// Bind the socket to the local IP address
// and port 27015
hostent* thisHost;
char* ip;
u_short port;
port = 27015;
thisHost = gethostbyname("");
ip = inet_ntoa (*(struct in_addr *)*thisHost->h_addr_list);
service.sin_family = AF_INET;
service.sin_addr.s_addr = inet_addr(ip);
service.sin_port = htons(port);
if ( bind( ListenSocket,(SOCKADDR*) &service, sizeof(service) )== SOCKET_ERROR ) {
printf("bind failed\n");
closesocket(ListenSocket);
return 0;
}
//---------------------------------------
// Initialize variables and call getsockopt.
// The SO_ACCEPTCONN parameter is a socket option
// that tells the function to check whether the
// socket has been put in listening mode or not.
// The various socket options return different
// information about the socket. This call should
// return 0 to the optVal parameter, since the socket
// is not in listening mode.
int optVal;
int optLen = sizeof(int);
if (getsockopt(ListenSocket,
SOL_SOCKET,
SO_ACCEPTCONN,
(char*)&optVal,
&optLen) != SOCKET_ERROR)
printf("SockOpt Value: %ld\n", optVal);
//---------------------------------------
// Put the listening socket in listening mode.
if (listen( ListenSocket, 100 ) == SOCKET_ERROR) {
printf("error listening\n");
}
//---------------------------------------
// Call getsockopt again to verify that
// the socket is in listening mode.
if (getsockopt(ListenSocket,
SOL_SOCKET,
SO_ACCEPTCONN,
(char*)&optVal,
&optLen) != SOCKET_ERROR)
printf("SockOpt Value: %ld\n", optVal);
WSACleanup();
return 0;
}
SO_ACCEPTCONN这个选项是用来判断socket是否处于监听状态，程序的输出是正确的啊。 #include <stdio.h>
#include <sys/socket.h>
#include <unistd.h>
int main(void)
{
int bufsize = 0;
int nLen = 0;
int tcpfd = socket(AF_INET, SOCK_STREAM, 0);
nLen = sizeof(bufsize);
getsockopt(tcpfd, SOL_SOCKET, SO_RCVBUF, &bufsize, &nLen);
printf("TCP RecvBuf = %d\n", bufsize);
nLen = sizeof(bufsize);
getsockopt(tcpfd, SOL_SOCKET, SO_SNDBUF, &bufsize, &nLen);
printf("TCP SendBuf = %d\n", bufsize);
int udpfd = socket(AF_INET, SOCK_DGRAM, 0);
nLen = sizeof(bufsize);
getsockopt(udpfd, SOL_SOCKET, SO_RCVBUF, &bufsize, &nLen);
printf("UDP RecvBuf = %d\n", bufsize);
nLen = sizeof(bufsize);
getsockopt(udpfd, SOL_SOCKET, SO_SNDBUF, &bufsize, &nLen);
printf("UDP SendBuf = %d\n", bufsize);
close(tcpfd);
close(udpfd);
return 0;
}
这是linux系统查看socket发送/接收缓冲区大小的代码，windows也差不多。
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