【原创】TCP Socket 简单练习 --- select同时监测多个描述符 分类: Linux --- 应用程序设计 2014-12-23 10:33 75人阅读 评论(0) 收藏
【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: genglut@163.com > 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 1024 void 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_in unsigned 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; int maxfd = -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]); else server_port = 6666; if(argv[1] && argv[2] && argv[3])//与上面道理相同 lisnum = atoi(argv[3]); else lisnum = 5; bzero(&server_addr, sizeof(server_addr));//也可以用memset server_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sockfd if((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_addr if(bind(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1) { perror("bind"); exit(EXIT_FAILURE); } //监听sockfd if(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 ntohs printf("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1s tv.tv_usec = 0; retval = select(maxfd, &rfds, NULL, NULL, &tv);//多路复用,同时监测描述符0和newfd if(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buf fgets(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buf fgets(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: genglut@163.com > 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 1024 int 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; int maxfd = -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1s tv.tv_usec = 0; retval = select(maxfd, &rfds, NULL, NULL, &tv);//多路复用,同时监测描述符0和newfd if(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buf fgets(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
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