服务器代码：
#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 <fcntl.h>
#include <sys/epoll.h>
#include <sys/time.h>
#include <sys/resource.h>
#define MAXBUF 1024
#define MAXEPOLLSIZE 10000
/*
* setnonblocking - 设置句柄为非阻塞方式
*/
int setnonblocking(int sockfd)
{
if (fcntl(sockfd, F_SETFL, fcntl(sockfd, F_GETFD, 0)|O_NONBLOCK) == -1)
{
return -1;
}
return 0;
}
/*
* handle_message - 处理每个 socket 上的消息收发
*/
int handle_message(int new_fd)
{
char buf[MAXBUF + 1];
int len;
/* 开始处理每个新连接上的数据收发 */
bzero(buf, MAXBUF + 1);
/* 接收客户端的消息 */
len = recv(new_fd, buf, MAXBUF, 0);
if (len > 0)
{
printf("%d接收消息成功:'%s'，共%d个字节的数据\n",
new_fd, buf, len);
}
else
{
if (len < 0)
printf("消息接收失败！错误代码是%d，错误信息是'%s'\n",
errno, strerror(errno));
close(new_fd);
return -1;
}
/* 处理每个新连接上的数据收发结束 */
return len;
}
int main(int argc, char **argv)
{
int listener, new_fd, kdpfd, nfds, n, ret, curfds;
socklen_t len;
struct sockaddr_in my_addr, their_addr;
unsigned int myport, lisnum;
struct epoll_event ev;
struct epoll_event events[MAXEPOLLSIZE];
struct rlimit rt;
myport = 5000;
lisnum = 2;
/* 设置每个进程允许打开的最大文件数 */
rt.rlim_max = rt.rlim_cur = MAXEPOLLSIZE;
if (setrlimit(RLIMIT_NOFILE, &rt) == -1)
{
perror("setrlimit");
exit(1);
}
else
{
printf("设置系统资源参数成功！\n");
}
/* 开启 socket 监听 */
if ((listener = socket(PF_INET, SOCK_STREAM, 0)) == -1)
{
perror("socket");
exit(1);
}
else
{
printf("socket 创建成功！\n");
}
setnonblocking(listener);
bzero(&my_addr, sizeof(my_addr));
my_addr.sin_family = PF_INET;
my_addr.sin_port = htons(myport);
my_addr.sin_addr.s_addr = INADDR_ANY;
if (bind(listener, (struct sockaddr *) &my_addr, sizeof(struct sockaddr)) == -1)
{
perror("bind");
exit(1);
}
else
{
printf("IP 地址和端口绑定成功\n");
}
if (listen(listener, lisnum) == -1)
{
perror("listen");
exit(1);
}
else
{
printf("开启服务成功！\n");
}
/* 创建 epoll 句柄，把监听 socket 加入到 epoll 集合里 */
kdpfd = epoll_create(MAXEPOLLSIZE);
len = sizeof(struct sockaddr_in);
ev.events = EPOLLIN | EPOLLET;
ev.data.fd = listener;
if (epoll_ctl(kdpfd, EPOLL_CTL_ADD, listener, &ev) < 0)
{
fprintf(stderr, "epoll set insertion error: fd=%d\n", listener);
return -1;
}
else
{
printf("监听 socket 加入 epoll 成功！\n");
}
curfds = 1;
while (1)
{
/* 等待有事件发生 */
nfds = epoll_wait(kdpfd, events, curfds, -1);
if (nfds == -1)
{
perror("epoll_wait");
break;
}
/* 处理所有事件 */
for (n = 0; n < nfds; ++n)
{
if (events[n].data.fd == listener)
{
new_fd = accept(listener, (struct sockaddr *) &their_addr,&len);
if (new_fd < 0)
{
perror("accept");
continue;
}
else
{
printf("有连接来自于： %d:%d， 分配的 socket 为:%d\n",
inet_ntoa(their_addr.sin_addr), ntohs(their_addr.sin_port), new_fd);
}
setnonblocking(new_fd);
ev.events = EPOLLIN | EPOLLET;
ev.data.fd = new_fd;
if (epoll_ctl(kdpfd, EPOLL_CTL_ADD, new_fd, &ev) < 0)
{
fprintf(stderr, "把 socket '%d' 加入 epoll 失败！%s\n",
new_fd, strerror(errno));
return -1;
}
curfds++;
}
else
{
ret = handle_message(events[n].data.fd);
if (ret < 1 && errno != 11)
{
epoll_ctl(kdpfd, EPOLL_CTL_DEL, events[n].data.fd,&ev);
curfds--;
}
}
}
}
close(listener);
return 0;
}
客户端代码：
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define PORT 5000 /* Server的端口 */
#define MAXDATASIZE 100 /* 一次可以读的最大字节数 */
int main(int argc, char *argv[])
{
int sockfd, numbytes;
struct hostent *he; /* 主机信息 */
struct sockaddr_in their_addr; /* 对方地址信息 */
if (argc != 2)
{
fprintf(stderr,"usage: client hostname\n");
exit(1);
}
/* get the host info */
if ((he = gethostbyname(argv[1])) == NULL)
{
/* 注意：获取DNS信息时，显示出错需要用herror而不是perror */
herror("gethostbyname");
exit(1);
}
if ((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1)
{
perror("socket");
exit(1);
}
their_addr.sin_family = AF_INET;
their_addr.sin_port = htons(PORT); /* short, NBO */
their_addr.sin_addr = *((struct in_addr *)he->h_addr);
bzero(&(their_addr.sin_zero), 8); /* 其余部分设成0 */
if (connect(sockfd, (struct sockaddr *)&their_addr, sizeof(struct sockaddr)) == -1)
{
perror("connect");
exit(1);
}
char* pMsg= "Hello,world!";
if ((numbytes = send(sockfd, pMsg, strlen(pMsg), 0)) == -1)
{
perror("send");
exit(1);
}
close(sockfd);
return 0;
}