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Linux c==网络编程、循环服务器、并发服务器、I/O多路转接

2016-12-04 22:32 549 查看
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netdb.h>

#define PORT 3333
#define MAX_SIZE 1024

int main()
{
int sockfd;
int new_fd;

struct sockaddr_in server_addr;
struct sockaddr_in client_addr;

int n_read;
int ser_size;
int opt = 1;

char buffer[MAX_SIZE];

if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
{
perror("socket error!\n");
exit(1);
}

printf("socket success.............!\n");

if(setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt)) < 0)
{
perror("set socket option error!\n");
exit(1);
}

bzero(&server_addr,0);
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
server_addr.sin_addr.s_addr = inet_addr("192.168.1.10");

if(bind(sockfd,(struct sockaddr *)&server_addr,sizeof server_addr) < 0)
{
perror("bind error!\n");
exit(1);
}

printf("bind success.............!\n");
listen(sockfd,5);

printf("listen success.............!\n");

printf("accepting..................!\n");

while(1)
{
ser_size = sizeof client_addr;

if((new_fd = accept(sockfd,(struct sockaddr *)&client_addr,&ser_size)) < 0)
{
perror("accept error!\n");
exit(1);
}

printf("accept success.................!\n");

//read\recv

printf("reading............!\n");
n_read = read(new_fd,buffer,sizeof(buffer));

if(n_read < 0)
{
perror("read client msg error!\n");
exit(1);
}

buffer[n_read] = '\0';

printf("recv msg = %s\n",buffer);
}

return 0;
}
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[/code]

客户端:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>

#define PORT 3333
#define MAX_SIZE 1024

int main(int argc, char *argv[])
{
if(argc != 2)
{
printf("Please input server ip!\n");
exit(1);
}

int sockfd;
int n_write;

struct sockaddr_in server_addr;

char buffer[MAX_SIZE];

if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
{
perror("client socket error!\n");
exit(1);
}

bzero(&server_addr,0);

server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
server_addr.sin_addr.s_addr = inet_addr(argv[1]);

if(connect(sockfd,(struct sockaddr *)&server_addr,sizeof server_addr) < 0)
{
perror("connect server error!\n");
exit(1);
}

while(1)
{
memset(buffer,0,sizeof(buffer));
printf("Please input send msg:\n");
gets(buffer);

n_write = write(sockfd,buffer,strlen(buffer));

if(n_write == -1)
{
perror("send to server msg error!\n");
exit(1);
}
}

return 0;
}
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[/code]

缺点:只能接收到一个客户端,且等待其结束后才能接受下一个客户端

并发服务器:

服务器:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <netdb.h>

#define PORT 3333
#define MAX_SIZE 1024

void * read_msg(void *arg)
{
int n_read;

int new_fd = *((int *)arg);

char buffer[MAX_SIZE];

printf("new_fd = %d\n",new_fd);

while(1)
{
memset(buffer,0,sizeof(buffer));

n_read = read(new_fd,buffer,sizeof(buffer));

if(n_read < 0)
{
perror("recv client msg error!\n");
exit(1);
}

if(n_read == 0)
{
printf("client is close!!\n");
close(new_fd);
pthread_exit(NULL);
}

buffer[n_read] = '\0';

printf("recv msg:%s\n",buffer);
}
}

int main()
{
int sockfd;
int new_fd;

struct sockaddr_in server_addr;
struct sockaddr_in client_addr;

int n_read;
int ser_size;
int opt = 1;

char buffer[MAX_SIZE];

pthread_t id;

if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
{
perror("socket error!\n");
exit(1);
}

printf("socket success.............!\n");

if(setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt)) < 0)
{
perror("set socket option error!\n");
exit(1);
}

bzero(&server_addr,0);
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
server_addr.sin_addr.s_addr = inet_addr("192.168.1.10");

if(bind(sockfd,(struct sockaddr *)&server_addr,sizeof server_addr) < 0)
{
perror("bind error!\n");
exit(1);
}

printf("bind success.............!\n");
listen(sockfd,5);

printf("listen success.............!\n");

printf("accepting..................!\n");

while(1)
{
ser_size = sizeof client_addr;

if((new_fd = accept(sockfd,(struct sockaddr *)&client_addr,&ser_size)) < 0)
{
perror("accept error!\n");
exit(1);
}

printf("accept success.................!\n");

pthread_create(&id,NULL,read_msg,&new_fd);
}

return 0;
}
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[/code]

客户端:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>

#define PORT 3333
#define MAX_SIZE 1024

int main(int argc, char *argv[])
{
if(argc != 2)
{
printf("Please input server ip!\n");
exit(1);
}

int sockfd;
int n_write;

struct sockaddr_in server_addr;

char buffer[MAX_SIZE];

if((sockfd = socket(AF_INET,SOCK_STREAM,0)) < 0)
{
perror("client socket error!\n");
exit(1);
}

bzero(&server_addr,0);

server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(PORT);
server_addr.sin_addr.s_addr = inet_addr(argv[1]);

if(connect(sockfd,(struct sockaddr *)&server_addr,sizeof server_addr) < 0)
{
perror("connect server error!\n");
exit(1);
}

while(1)
{
memset(buffer,0,sizeof(buffer));
printf("Please input send msg:\n");
gets(buffer);

n_write = write(sockfd,buffer,strlen(buffer));

if(n_write == -1)
{
perror("send to server msg error!\n");
exit(1);
}
}

return 0;
}
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[/code]

缺点:在客户端没有发送数据时,每个线程仍需轮流切换,浪费CPU资源

I/O多路转接:

服务器:
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include<unistd.h>
#include<arpa/inet.h>
#include<ctype.h>

/* 宏定义端口号 */
#define portnumber 8000

#define MAX_LINE 80

int main(void)
{
int  lfd;
int cfd;
int sfd;
int rdy;

struct sockaddr_in sin;
struct sockaddr_in cin;

int client[FD_SETSIZE];  /* 客户端连接的套接字描述符数组 */

int maxi;
int maxfd;                        /* 最大连接数 */

fd_set rset;
fd_set allset;

socklen_t addr_len;         /* 地址结构长度 */

char buffer[MAX_LINE];

int i;
int n;
int len;
int opt = 1;   /* 套接字选项 */

char addr_p[20];

/* 对server_addr_in  结构进行赋值  */
bzero(&sin,sizeof(struct sockaddr_in));   /* 先清零 */
sin.sin_family=AF_INET;                 //
sin.sin_addr.s_addr=htonl(INADDR_ANY);  //表示接受任何ip地址   将ip地址转换成网络字节序
sin.sin_port=htons(portnumber);         //将端口号转换成网络字节序

/* 调用socket函数创建一个TCP协议套接口 */
if((lfd=socket(AF_INET,SOCK_STREAM,0))==-1) // AF_INET:IPV4;SOCK_STREAM:TCP
{
fprintf(stderr,"Socket error:%s\n\a",strerror(errno));
exit(1);
}
printf("socket!\n");

/*设置套接字选项 使用默认选项*/
setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

/* 调用bind函数 将serer_addr结构绑定到sockfd上  */
if(bind(lfd,(struct sockaddr *)(&sin),sizeof(struct sockaddr))==-1)
{
fprintf(stderr,"Bind error:%s\n\a",strerror(errno));
exit(1);
}
printf("bind!\n");

/* 开始监听端口   等待客户的请求 */
if(listen(lfd,20)==-1)
{
fprintf(stderr,"Listen error:%s\n\a",strerror(errno));
exit(1);
}
printf("listen!\n");
printf("Accepting connections .......\n");

maxfd = lfd;                                /*对最大文件描述符进行初始化*/
maxi = -1;

/*初始化客户端连接描述符集合*/
for(i = 0;i < FD_SETSIZE;i++)
{
client[i] = -1;
}

FD_ZERO(&allset);                     /* 清空文件描述符集合 */
FD_SET(lfd,&allset);                    /* 将监听字设置在集合内 */

/* 开始服务程序的死循环 */
while(1)
{
rset = allset;
printf("selecting!\n");
/*得到当前可以读的文件描述符数*/
rdy = select(maxfd + 1, &rset, NULL, NULL, NULL);

printf("selected!\n");
if(FD_ISSET(lfd, &rset))
{

addr_len = sizeof(sin);
printf("accepting!\n");
/* 接受客户端的请求 */
if((cfd=accept(lfd,(struct sockaddr *)(&cin),&addr_len))==-1)
{
fprintf(stderr,"Accept error:%s\n\a",strerror(errno));
exit(1);
}
printf("accepted!\n");

/*查找一个空闲位置*/
for(i = 0; i<FD_SETSIZE; i++)
{       //printf("%d\t",client[i]);
if(client[i] <= 0)
{
client[i] = cfd;   /* 将处理该客户端的连接套接字设置到该位置 */
break;
}
}

/* 太多的客户端连接   服务器拒绝俄请求  跳出循环 */
if(i == FD_SETSIZE)
{
printf("too many clients");
exit(1);
}

FD_SET(cfd, &allset);     /* 设置连接集合 */

if(cfd > maxfd)                  /* 新的连接描述符 */
{
maxfd = cfd;
}

if(i > maxi)
{
maxi = i;
}

if(--rdy <= 0)                /* 减少一个连接描述符 */
{
continue;
}

}

/* 对每一个连接描述符做处理 */
for(i = 0;i< FD_SETSIZE;i++)
{
if((sfd = client[i]) < 0)
{
continue;
}

if(FD_ISSET(sfd, &rset))
{
printf("reading!\n");
n = read(sfd,buffer,MAX_LINE);
printf("%s\n",buffer);
printf("read!\n");
if(n == 0)
{
printf("the other side has been closed. \n");
fflush(stdout);                                    /* 刷新 输出终端 */
close(sfd);

FD_CLR(sfd, &allset);                        /*清空连接描述符数组*/
client[i] = -1;
}

else
{
/* 将客户端地址转换成字符串 */
inet_ntop(AF_INET, &cin.sin_addr, addr_p, sizeof(addr_p));
addr_p[strlen(addr_p)] = '\0';

/*打印客户端地址 和 端口号*/
printf("Client Ip is %s, port is %d\n",addr_p,ntohs(cin.sin_port));

/* 谐函数出错 */
if(n == 1)
{
exit(1);
}
}

/*如果没有可以读的套接字   退出循环*/
if(--rdy <= 0)
{
break;

}
}

}

close(lfd);       /* 关闭链接套接字 */
return 0;
}
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[/code]

客户端:
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>

#define portnumber 8000

int main(int argc, char *argv[])
{
int nbytes;
int sockfd;
char buffer[80];
char buffer_2[80];
struct sockaddr_in server_addr;
struct hostent *host;

if(argc!=2)
{
fprintf(stderr,"Usage:%s hostname \a\n",argv[0]);
exit(1);
}

if((host=gethostbyname(argv[1]))==NULL)
{
fprintf(stderr,"Gethostname error\n");
exit(1);
}

/* 调用socket函数创建一个TCP协议套接口 */
if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1) // AF_INET:Internet;SOCK_STREAM:TCP
{
fprintf(stderr,"Socket Error:%s\a\n",strerror(errno));
exit(1);
}

bzero(&server_addr,sizeof(server_addr)); //
server_addr.sin_family=AF_INET;
server_addr.sin_port=htons(portnumber);
server_addr.sin_addr = *((struct in_addr *)host->h_addr);//?

if(connect(sockfd,(struct sockaddr *)(&server_addr),sizeof(struct sockaddr))==-1)
{
fprintf(stderr,"Connect Error:%s\a\n",strerror(errno));
exit(1);
}

while(1){

printf("Please input char:\n");

fgets(buffer,1024,stdin);
write(sockfd,buffer,strlen(buffer));
#if 1
if((nbytes=read(sockfd,buffer_2,81))==-1)
{
fprintf(stderr,"Read Error:%s\n",strerror(errno));
exit(1);
}

buffer_2[nbytes]='\0';
printf("Client received from Server %s\n",buffer_2);
#endif

}
close(sockfd);
exit(0);
}
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[/code]

优点:使用select来充当监管作用

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