【原创】TCP Socket 简单练习 --- select同时监测多个描述符

【原创】TCP Socket 简单练习 --- select同时监测多个描述符

运行方式

服务器端，可以直接运行命令，也可以带参数运行，如果不带参数运行，则程序自主获取主机ip，然后默认设定port和lisnum的值。其中port默认为6666，lisnum默认为5.

./socket_select_server IP地址（可选） 端口号（可选）监听队列大小（可选）  

客户端，必须指定服务器的IP地址和端口号，例如：

./socket_select_client 172.18.229.60 6666  

服务器代码

/*************************************************************************> File Name: socket_select_server.c> Author: genglut> Mail: [e-mail]> Created Time: 2014年12月22日 星期一 18时06分26秒 ************************************************************************//*struct sockaddr_in {        short int sin_family;                // 地址协议        in_port_t sin_port;    　　　   // 端口号        struct in_addr sin_addr;         　　// IP地址       unsigned char sin_zero[8];     　　　// 预留位 };  struct in_addr {        _u32 s_addr;           　　// 32位地址  };*/#include <stdio.h>#include <stdlib.h>#include <errno.h>#include <string.h>#include <sys/types.h>#include <netinet/in.h>#include <sys/socket.h>#include <sys/wait.h>#include <unistd.h>#include <arpa/inet.h>#include <net/if.h>#include <sys/ioctl.h>#define MAXBUF 1024void get_ip(char * str, char *ip);//获取本地IP地址int main(int argc, char *argv[]){//用于测试命令行输入的值的情况//printf("argv[0] = %s\n", argv[0]);//printf("argv[1] = %s\n", argv[1]);//printf("argv[2] = %s\n", argv[2]);//printf("argv[3] = %s\n", argv[3]);int sockfd, newfd;socklen_t len;struct sockaddr_in server_addr, client_addr;//结构体sockaddr_inunsigned int server_port, lisnum;//用int也可以char buf[MAXBUF + 1];//下面是select用到的变量的定义fd_set rfds;struct timeval tv;int retval;intmaxfd = -1;if(argv[1] && argv[2])//要根据argv[1]的情况来判断argv[2]的情况，否则会出错server_port = atoi(argv[2]);elseserver_port = 6666;if(argv[1] && argv[2] && argv[3])//与上面道理相同lisnum = atoi(argv[3]);elselisnum = 5;bzero(&server_addr, sizeof(server_addr));//也可以用memsetserver_addr.sin_family = AF_INET;server_addr.sin_port = htons(server_port);//转换为网络字节序if(argv[1])//将ip地址转换为32位网络地址 inet_addr 也可以用inet_aton  //inet_aton(argv[1], (struct in_addr *) &dest.sin_addr.s_addr);server_addr.sin_addr.s_addr = inet_addr(argv[1]);else{char ip[128];get_ip("eno16777736", ip);server_addr.sin_addr.s_addr = inet_addr(ip);}//建立sockfdif((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){perror("socket");exit(EXIT_FAILURE);}//输出ip和port信息，用于测试printf("server_ip = %s\nserver_port = %d\nlisnum = %d\n", inet_ntoa(server_addr.sin_addr), server_port, lisnum);//绑定sockfd和服务器的IP地址server_addrif(bind(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1){perror("bind");exit(EXIT_FAILURE);}//监听sockfdif(listen(sockfd, lisnum) == -1){perror("listen");exit(EXIT_FAILURE);}while(1){printf("\n---- wait for client connect ---\n");//等待接收客户端的连接//连接成功后，客户端地址信息存储在client_addr中//新建立的socket描述符存储在newfd中len = sizeof(struct sockaddr);if((newfd = accept(sockfd, (struct sockaddr *)&client_addr, &len)) == -1){perror("accept");exit(EXIT_FAILURE);}//打印客户端地址信息 inet_ntoa  ntohsprintf("server: got connection from %s, port %d, socket %d\n", inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port), newfd);while(1){FD_ZERO(&rfds);//初始化rfds为空FD_SET(0, &rfds);//将标准输入的描述符0加入到集合rfds中FD_SET(newfd, &rfds);//将newfd加入到集合rfds中maxfd = newfd + 1;tv.tv_sec = 1;//阻塞等待时间为1stv.tv_usec = 0;retval = select(maxfd, &rfds, NULL, NULL, &tv);//多路复用，同时监测描述符0和newfdif(retval == -1)//select函数执行出错{perror("select");exit(EXIT_FAILURE);}else if(retval == 0)//select函数执行超时continue;else//有描述符引起异常{if(FD_ISSET(0, &rfds))//判断是不是标准输入0引起的异常{bzero(buf, sizeof(buf));//清空buffgets(buf, sizeof(buf)-1, stdin);//从终端接收输入if(!strncasecmp(buf, "quit", 4))//判断是否为退出{printf("i will close the connect!\n");break;}len = send(newfd, buf, strlen(buf)-1, 0);//向客户端发送消息if(len > 0){printf ("send successful,%d byte send!\n",len);}else{printf("message '%s' send failure !\n", buf);printf("errno code is %d, errno message is '%s'\n", errno, strerror(errno));break;}}if(FD_ISSET(newfd, &rfds))//判断是不是newfd引起的异常{bzero(buf, sizeof(buf));len = recv(newfd, buf, sizeof(buf)-1, 0);//从客户端接收消息if(len > 0 )printf("message recv successful : '%s', %d Byte recv\n", buf, len);else if(len < 0){printf("recv failure !\nerrno code is %d, errno message is '%s'\n", errno, strerror(errno));break;}else//如果客户端已关闭{printf("the other one close quit\n");break;}}}}close(newfd);printf("need other connection ? (no -> quit) : ");fflush(stdout);bzero(buf, sizeof(buf));//清空buffgets(buf, sizeof(buf)-1, stdin);//从终端接收输入if(!strncasecmp(buf, "no", 2))//判断是否继续等待连接{printf("quit!\n");break;}}close(sockfd);return 0;}void get_ip(char * str, char *ip){int inet_sock;struct ifreq ifr;inet_sock = socket(AF_INET, SOCK_DGRAM, 0);strcpy(ifr.ifr_name, str);//#include <net/if.h>if (ioctl(inet_sock, SIOCGIFADDR, &ifr) < 0)//#include <sys/ioctl.h>{perror("ioctl");exit(EXIT_FAILURE);}sprintf(ip,"%s", inet_ntoa(((struct sockaddr_in*)&(ifr.ifr_addr))->sin_addr));close(inet_sock);}

客户端代码

/*************************************************************************> File Name: socket_select_client.c> Author: genglut> Mail: [e-mail]> Created Time: 2014年12月22日 星期一 18时06分06秒 ************************************************************************/#include <stdio.h>#include <string.h>#include <errno.h>#include <sys/socket.h>#include <resolv.h>#include <stdlib.h>#include <netinet/in.h>#include <arpa/inet.h>#include <unistd.h>#define MAXBUF 1024int main(int argc, char *argv[]){int sockfd;socklen_t len;struct sockaddr_in server_addr;char buf[MAXBUF + 1];//下面是select用到的变量的定义fd_set rfds;struct timeval tv;int retval;intmaxfd = -1;if(argc != 3){printf("error failure, it must be:\n\t\t%s IP port \n", argv[0]);exit(EXIT_FAILURE);}if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1){perror("socket");exit(EXIT_FAILURE);}bzero(&server_addr, sizeof(server_addr));server_addr.sin_family = AF_INET;server_addr.sin_port = htons(atoi(argv[2]));server_addr.sin_addr.s_addr = inet_addr(argv[1]);if(connect(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1){perror("connect");exit(EXIT_FAILURE);}printf("already connected to server %s\n", argv[1]);while(1){FD_ZERO(&rfds);//初始化rfds为空FD_SET(0, &rfds);//将标准输入的描述符0加入到集合rfds中FD_SET(sockfd, &rfds);//将newfd加入到集合rfds中maxfd = sockfd + 1;tv.tv_sec = 1;//阻塞等待时间为1stv.tv_usec = 0;retval = select(maxfd, &rfds, NULL, NULL, &tv);//多路复用，同时监测描述符0和newfdif(retval == -1)//select函数执行出错{perror("select");exit(EXIT_FAILURE);}else if(retval == 0)//select函数执行超时continue;else//有描述符引起异常{if(FD_ISSET(0, &rfds))//判断是不是标准输入0引起的异常{bzero(buf, sizeof(buf));//清空buffgets(buf, sizeof(buf)-1, stdin);//从终端接收输入if(!strncasecmp(buf, "quit", 4))//判断是否为退出{printf("i will quit!\n");break;}len = send(sockfd, buf, strlen(buf)-1, 0);//向客户端发送消息if(len > 0){printf ("send successful,%d byte send!\n",len);}else{printf("message '%s' send failure !\n", buf);printf("errno code is %d, errno message is '%s'\n", errno, strerror(errno));break;}}if(FD_ISSET(sockfd, &rfds))//判断是不是newfd引起的异常{bzero(buf, sizeof(buf));len = recv(sockfd, buf, sizeof(buf)-1, 0);//从客户端接收消息if(len > 0 )printf("message recv successful : '%s', %d Byte recv\n", buf, len);else if(len < 0){printf("recv failure !\nerrno code is %d, errno message is '%s'\n", errno, strerror(errno));break;}else//如果客户端已关闭{printf("the other one close, quit\n");break;}}}}close(sockfd);printf("i quited!\n");return 0;}

原文链接

http://blog.csdn.net/geng823/article/details/42099569