套接字选项—修改套接字缓冲区大小

有时候我们需要控制套接字的行为(如修改缓冲区的大小),这个时候我们就要学习套接字选项。

 

int getsockopt(int sockfd,int level,int optname,void *optval,socklen_t *optlen) int setsockopt(int sockfd,int level,int optname,const void *optval,socklen_t *optlen)

 

level指定控制套接字的层次.可以取三种值:

1)SOL_SOCKET:通用套接字选项. 

2)IPPROTO_IP:IP选项. 

3)IPPROTO_TCP:TCP选项. 

optname指定控制的方式(选项的名称),我们下面详细解释 

optval获得或者是设置套接字选项.根据选项名称的数据类型进行转换 


选项名称                说明                                    数据类型
========================================================================
                        SOL_SOCKET
------------------------------------------------------------------------
SO_BROADCAST        允许发送广播数据                    int
SO_DEBUG                允许调试                                int
SO_DONTROUTE        不查找路由                             int
SO_ERROR                 获得套接字错误                       int
SO_KEEPALIVE          保持连接                                 int
SO_LINGER               延迟关闭连接                           struct linger
SO_OOBINLINE         带外数据放入正常数据流            int
SO_RCVBUF               接收缓冲区大小                        int
SO_SNDBUF               发送缓冲区大小                        int
SO_RCVLOWAT          接收缓冲区下限                        int
SO_SNDLOWAT          发送缓冲区下限                        int
SO_RCVTIMEO           接收超时                                 struct timeval
SO_SNDTIMEO           发送超时                                 struct timeval
SO_REUSERADDR       允许重用本地地址和端口            int
SO_TYPE                    获得套接字类型                         int
SO_BSDCOMPAT        与BSD系统兼容                         int
==========================================================================
                        IPPROTO_IP
--------------------------------------------------------------------------
IP_HDRINCL              在数据包中包含IP首部                    int
IP_OPTINOS              IP首部选项                                   int
IP_TOS                      服务类型
IP_TTL                       生存时间                                      int
==========================================================================
                        IPPRO_TCP
--------------------------------------------------------------------------
TCP_MAXSEG              TCP最大数据段的大小                     int
TCP_NODELAY            不使用Nagle算法                           int
=========================================================================

 

大致介绍这么多，还是看源码吧：

////////////////////////////////////////////////////////////////////////// // SocketOptionSrv.cpp // 套接字选项 —— 设置缓冲大小（扩大10倍） #include <iostream.h> #include <winsock2.H> #define BUF_SIZE 64 #pragma comment(lib,"ws2_32.lib") int main(int argc,char* argv[]) { WSADATA wsd; SOCKET s; SOCKADDR_IN servAddr; char bufRecv[BUF_SIZE]; char bufSend[BUF_SIZE]; // 初始化套接字 if(WSAStartup(MAKEWORD(2,2),&wsd)) { cout<<"WSAStartup failed !/n"<<endl; return 1; } // 连理套接字 s = socket(AF_INET,SOCK_DGRAM,0); if(INVALID_SOCKET == s) { cout<<"socket failed !/n"<<endl; WSACleanup(); return 1; } int nErrorCode; int nBufLen; int nOptLen = sizeof(nBufLen); // 获取当前套接字s的接受数据缓冲区大小 nErrorCode = getsockopt(s,SOL_SOCKET,SO_RCVBUF,(char*)&nBufLen,&nOptLen); if(SOCKET_ERROR == nErrorCode) { cout<<"getsockopt failed !/n"<<endl; WSACleanup(); return 1; } // 设置当前套接字s的接受数据缓冲区为原来的10倍 nBufLen *= 10; nErrorCode = setsockopt(s,SOL_SOCKET,SO_RCVBUF,(char*)&nBufLen,nOptLen); if(SOCKET_ERROR == nErrorCode) { cout<<"setsockopt failed !/n"<<endl; WSACleanup(); return 1; } // 检查套接字s的接受缓冲区是否设置成功 int uiNewRcvBuf; getsockopt(s,SOL_SOCKET,SO_RCVBUF,(char*)&uiNewRcvBuf,&nOptLen); if(SOCKET_ERROR == nErrorCode || uiNewRcvBuf != nBufLen) { cout<<"The buf isn't same from Recv."<<endl; WSACleanup(); return 1; } // 设置服务器现象 servAddr.sin_family = AF_INET; servAddr.sin_port = htons(5000); servAddr.sin_addr.s_addr = htonl(INADDR_ANY); // 绑定套接字 if(bind(s,(SOCKADDR *)&servAddr,sizeof(SOCKADDR)) == SOCKET_ERROR) { cout<<"bind failed:"<<WSAGetLastError()<<endl; closesocket(s); WSACleanup(); return 1; } SOCKADDR_IN clientAddr; int nClientLen; // 缓冲区待发送的数据 ZeroMemory(bufRecv,BUF_SIZE); ZeroMemory(bufSend,BUF_SIZE); strcpy(bufSend,"Hello World !"); nClientLen = sizeof(clientAddr); while(1) { // 从客户端接受数据 if(recvfrom(s,bufRecv,BUF_SIZE,0,(SOCKADDR *)&clientAddr,&nClientLen) == SOCKET_ERROR) { cout<<"recv failed:"<<WSAGetLastError()<<endl; closesocket(s); WSACleanup(); return 1; } cout<<"Recv From Client:"<<bufRecv<<endl; // 向服务器发送数据 if(sendto(s,bufSend,BUF_SIZE,0,(SOCKADDR *)&clientAddr,nClientLen) == SOCKET_ERROR) { cout<<"send to Client failed:"<<WSAGetLastError()<<endl; closesocket(s); WSACleanup(); return 1; } } // 关闭套接字，释放资源 closesocket(s); WSACleanup(); return 0; }

 

////////////////////////////////////////////////////////////////////////// // SocketOptionClient.cpp // 套接字选项 —— 设置缓冲大小（扩大10倍） #include <iostream.h> #include <winsock2.H> #define BUF_SIZE 64 #pragma comment(lib,"ws2_32.lib") int main(int argc,char* argv[]) { WSADATA wsd; SOCKET s; SOCKADDR_IN servAddr; char bufRecv[BUF_SIZE]; char bufSend[BUF_SIZE]; // 初始化套接字 if(WSAStartup(MAKEWORD(2,2),&wsd)) { cout<<"WSAStartup failed !/n"<<endl; return 1; } // 建立套接字 s = socket(AF_INET,SOCK_DGRAM,0); if(INVALID_SOCKET == s) { cout<<"socket failed !/n"<<endl; WSACleanup(); return 1; } // 缓冲区待发送的数据 ZeroMemory(bufSend,BUF_SIZE); ZeroMemory(bufRecv,BUF_SIZE); strcpy(bufSend,"Hello World !"); // 设置服务器选项 servAddr.sin_family = AF_INET; servAddr.sin_addr.s_addr = inet_addr("192.168.1.254"); servAddr.sin_port = htons(5000); int nServerlen = sizeof(servAddr); while(1) { // 向服务器发送数据 if(sendto(s,bufSend,BUF_SIZE,0,(SOCKADDR *)&servAddr,nServerlen) == SOCKET_ERROR) { cout<<"sendto failed:"<<WSAGetLastError()<<endl; closesocket(s); WSACleanup(); return 1; } // 从服务器接受数据 if(recvfrom(s,bufRecv,BUF_SIZE,0,(SOCKADDR *)&servAddr,&nServerlen) == SOCKET_ERROR) { cout<<"recv failed:"<<WSAGetLastError()<<endl; closesocket(s); WSACleanup(); return 1; } cout<<"Recv From Server:"<<bufRecv<<endl; } // 关闭套接字，释放资源 closesocket(s); WSACleanup(); return 0; }

 

 

程序运行效果：

 

 

源码下载地址：

 

http://download.csdn.net/source/1676947