网站seo优化加推广,建筑网站主页,在电脑上怎么卸载wordpress,剖析材料范文哪个网站做的好设计灵感:
1 单线程io多路复用服务端
2 使用poll实现
3 将server_sockfd client_sockfd 设为非阻塞,实现最大io效率
4 使用套接字选项SO_REUSEADDR 用于测试环境调试
5 将server_sockfd 和每一个有效的client_sockfd 都设为poll的监控事件
6 有客户端关闭连接时,自动从数…设计灵感:
1 单线程io多路复用服务端
2 使用poll实现
3 将server_sockfd client_sockfd 设为非阻塞,实现最大io效率
4 使用套接字选项SO_REUSEADDR 用于测试环境调试
5 将server_sockfd 和每一个有效的client_sockfd 都设为poll的监控事件
6 有客户端关闭连接时,自动从数组中删除,并调整相应的count值
功能:
可实现多客户端同时连接,echo收发无感
注意事项:
1 运行环境 unix-like gnu_c
2 开启服务端后 可无限开启客户端
3 赠送对比用双循环阻塞服务端
4 赠送测试用客户端
poll多路复用服务端:
#define _GNU_SOURCE
#include stdio.h
#include sys/socket.h
#include sys/un.h
#include fcntl.h
#include arpa/inet.h
#include netinet/in.h
#include sys/poll.h
#include stdlib.h
#include string.h
#include unistd.h#define SERVER_IP 192.168.142.132
#define SERVER_PORT 50013
// 设置非阻塞用函数
void set_non_blocking(int sockfd)
{// 获取默认flagsint flags fcntl(sockfd, F_GETFL, 0);if (flags -1){perror(fcntl F_GETFL);}// 位运算 加上O_NONBLOCKflags | O_NONBLOCK;// 设置 flagsif (fcntl(sockfd, F_SETFL, flags) -1){perror(fcntl F_SETFL);}
}
int main()
{int server_sockfd, client_sockfd;struct sockaddr_in server_sockaddr, client_sockaddr;memset(server_sockaddr, 0, sizeof(server_sockaddr));memset(client_sockaddr, 0, sizeof(client_sockaddr));socklen_t client_sockaddr_len sizeof(client_sockaddr);socklen_t server_sockaddr_len sizeof(server_sockaddr);ssize_t send_bytes, recv_bytes;char send_buf[1024] How can I he53453oday ?;char recv_buf[1024] {0};// 循环用i,j,计数用count:pollfds[count]中每增加一个元素 countint i 0, j 0, count 0;// 系统允许的单进程 最大fd数量 1024576long max_fds sysconf(_SC_OPEN_MAX);// 创建一个最大fd数量的数组,并将所有元素的所有字段设为0struct pollfd *pollfds calloc(max_fds, sizeof(struct pollfd));if (pollfds NULL){perror(calloc);}// 将每个元素的fd设为-1,表示无效for (i 0; i max_fds; i){pollfds[i].fd -1;}// 又名 listen socket 用于监听请求,ipv4 tcpserver_sockfd socket(AF_INET, SOCK_STREAM, 0);if (server_sockfd -1){perror(socket);}// 为什么要将server_sockfd设为非阻塞?// server_sockfd相关的accept被poll监视,只有读就绪(有连接到来时)才回调用accept// 这意味着accept通常不会阻塞,但是在极端情况下,客户端连接有迅速关闭,则accept有可能阻塞set_non_blocking(server_sockfd);// SO_REUSEADDR 地址端口复用,任意时刻只有一个socket能监听,主要用于程序重启// SO_REUSEPORT 地址端口复用,同时监听,自动负载均衡int optval 1;if (setsockopt(server_sockfd, SOL_SOCKET, SO_REUSEADDR, optval, sizeof(optval)) -1){perror(setsockopt);}// 设置协议server_sockaddr.sin_family AF_INET;// 设置转换端口server_sockaddr.sin_port htons(SERVER_PORT);// 设置转换ip地址if (inet_pton(AF_INET, SERVER_IP, server_sockaddr.sin_addr.s_addr) -1){perror(inet_pton);}// 绑定if (bind(server_sockfd, (struct sockaddr *)server_sockaddr, server_sockaddr_len) -1){perror(bind);}// 监听,调整了最大等待数量为1024if (listen(server_sockfd, 1024) -1){perror(listen);}// 将server_sockfd加入POLLIN监听事件pollfds[0].fd server_sockfd;pollfds[0].events POLLIN;// count现在是0,后变成1,遍历icount,也就是判断pollfds[0]// 但是pollfds[0]读就绪后,主要执行逻辑是accept,因此单独判断count;printf(server start...\n);while (1){// 如果没有事件真实发生,程序将阻塞在此,而不是一味地循环int r poll(pollfds, count, -1);// 至少有一个revent被设置if (r 0){// 如果有连接请求if (pollfds[0].revents POLLIN){// 就连接client_sockfd accept(server_sockfd, (struct sockaddr *)client_sockaddr, client_sockaddr_len);if (client_sockfd -1){perror(accept);}// 将返回的client_sockfd设为非阻塞set_non_blocking(client_sockfd);// 如果代码首次到这,count就是1,pollfds[1]被填充,符合逻辑pollfds[count].fd client_sockfd;// 同时监控读写pollfds[count].events POLLIN | POLLOUT;// 向后挪一位count;}// 首次加入监控事件的accept返回的client_sockfd不会在本次循环中被poll监控,需要等到下次循环for (i 1; i count; i){// 从索引1开始(索引0用于accept已单独处理),如果被监控的fd读就绪if (pollfds[i].revents POLLIN){// 读recv_bytes recv(pollfds[i].fd, recv_buf, sizeof(recv_buf), 0);if (recv_bytes -1){perror(recv);}// 如果客户端关闭了连接if (recv_bytes 0){printf(close by peer\n);// 服务器也关闭连接close(pollfds[i].fd);// 1 将后面的fd往前挪for (j i; j count - 1; j){pollfds[j] pollfds[j 1];}// 2 最后一个fd是一个无效的副本 手动重置pollfds[count - 1].fd -1;pollfds[count - 1].events 0;pollfds[count - 1].revents 0;// 3 count应该减1count--;}// 收到了数据if (recv_bytes 0){// 打印收到的数据printf(%s\n, recv_buf);// 同时,如果这个fd是写就绪的if (pollfds[i].revents POLLOUT){// 写send_bytes send(pollfds[i].fd, send_buf, strlen(send_buf), 0);if (send_bytes -1){perror(send);}}}}}}if (r -1){perror(poll);}}// 关闭server_sockfd,代码不可达close(server_sockfd);// 释放动态分配的内存,代码不可达free(pollfds);return 0;
}对比用双循环阻塞服务端:
#define _GNU_SOURCE
#include stdio.h
#include sys/socket.h
#include sys/un.h
#include arpa/inet.h
#include netinet/in.h
#include string.h
#include unistd.h#define SERVER_IP 192.168.142.132
#define SERVER_PORT 50013int main()
{int server_sockfd, client_sockfd;struct sockaddr_in server_sockaddr, client_sockaddr;memset(server_sockaddr, 0, sizeof(server_sockaddr));memset(client_sockaddr, 0, sizeof(client_sockaddr));socklen_t client_sockaddr_len sizeof(client_sockaddr);ssize_t send_bytes, recv_bytes;char send_buf[1024] How can I help you today ?;char recv_buf[1024] {0};server_sockfd socket(AF_INET, SOCK_STREAM, 0);if (server_sockfd -1){perror(socket);}int optval 1;setsockopt(server_sockfd, SOL_SOCKET, SO_REUSEADDR, optval, sizeof(optval));server_sockaddr.sin_family AF_INET;inet_pton(AF_INET, SERVER_IP, server_sockaddr.sin_addr.s_addr);server_sockaddr.sin_port htons(SERVER_PORT);if (bind(server_sockfd, (struct sockaddr *)server_sockaddr, sizeof(server_sockaddr)) -1){perror(bind);}if (listen(server_sockfd, 16) -1){perror(listen);}printf(server start...\n);while (1){client_sockfd accept(server_sockfd, (struct sockaddr *)client_sockaddr, client_sockaddr_len);if (client_sockfd -1){perror(accept);}while (1){recv_bytes recv(client_sockfd, recv_buf, sizeof(recv_buf), 0);if (recv_bytes -1){perror(recv);}else if (recv_bytes 0){printf(closed by peer\n);break;}else{printf(%s\n, recv_buf);}send_bytes send(client_sockfd, send_buf, strlen(send_buf), 0);if (send_bytes -1){perror(send);}}}close(server_sockfd);return 0;
}测试用客户端:
#define _GNU_SOURCE
#include stdio.h
#include sys/socket.h
#include sys/un.h
#include arpa/inet.h
#include netinet/in.h
#include string.h
#include unistd.h
#include stdlib.h
#include time.h
#include fcntl.h
#define SERVER_IP 192.168.142.132
#define SERVER_PORT 50013
int set_non_blocking(int sockfd)
{int flags fcntl(sockfd, F_GETFL, 0);if (flags -1){perror(fcntl(F_GETFL));}flags | O_NONBLOCK;if (fcntl(sockfd, F_SETFL, flags) -1){perror(fcntl(F_SETFL));}return 0;
}
int main()
{int client_sockfd;struct sockaddr_in server_sockaddr, client_sockaddr;memset(server_sockaddr, 0, sizeof(server_sockaddr));memset(client_sockaddr, 0, sizeof(client_sockaddr));socklen_t client_sockaddr_len sizeof(client_sockaddr);ssize_t send_bytes, recv_bytes;char send_buf[1024] {0};char recv_buf[1024] {0};client_sockfd socket(AF_INET, SOCK_STREAM, 0);if (client_sockfd -1){perror(socket);}//set_non_blocking(client_sockfd);inet_pton(AF_INET, SERVER_IP, server_sockaddr.sin_addr.s_addr);server_sockaddr.sin_port htons(SERVER_PORT);server_sockaddr.sin_family AF_INET;if (connect(client_sockfd, (struct sockaddr *)server_sockaddr, sizeof(server_sockaddr)) -1){perror(connect);}getsockname(client_sockfd, (struct sockaddr *)client_sockaddr, client_sockaddr_len);snprintf(send_buf, sizeof(send_buf), %u:he###llo s???ver !!!,ntohs(client_sockaddr.sin_port));while (1){send_bytes send(client_sockfd, send_buf, strlen(send_buf), 0);if (send_bytes -1){perror(send);}recv_bytes recv(client_sockfd, recv_buf, sizeof(recv_buf), 0);if (recv_bytes -1){perror(recv);}printf(%s\n, recv_buf);sleep(2);}close(client_sockfd);return 0;
}
