TCP协议----客户端与客户端之间通信

服务器

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>

#define PORT 123

struct info     //定义结构体用于存放套接字的描述符，以及来自客户端发送的消息内容
{
int num;
char buf[100];
};

void *Recv(void *arg)
{
pthread_detach(pthread_self());   //线程分离，确保资源的释放

struct info Buff;
int ret;

while(1)
{
ret = recv(*(int *)arg,&Buff,sizeof(Buff),0);  //接收客户端的消息
if(-1 == ret)
{
perror("recv");
exit(1);
}
if(!strcmp(Buff.buf,"bye"))
{
close(*(int *)arg);
break;
}

printf("Recv form client %d : %s\n",*(int *)arg,Buff.buf);

ret = send(Buff.num,&Buff,sizeof(Buff),0);  //将消息发送给客户端
if(-1 == ret)
{
perror("send");
exit(1);
}

memset(&Buff,0,sizeof(Buff));
}

}

int main()
{
int sockfd,ret,fd[100] = {0};
pthread_t tid[100] = {0};
int i = 0;
int length;
struct sockaddr_in server_addr;
struct sockaddr_in client_addr;

printf("Start ....\n");
sockfd = socket(PF_INET,SOCK_STREAM,0);   //创建socket
if(-1 == sockfd)
{
perror("socket");
exit(1);
}

int opt = 1;
setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));

memset(&server_addr,0,sizeof(server_addr));
server_addr.sin_family = PF_INET;
server_addr.sin_port = PORT;
server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

printf("Binding ....\n");
ret = bind(sockfd,(struct sockaddr*)&server_addr,sizeof(server_addr));  //将信息绑定到socket
if(-1 == ret)
{
perror("bind");
exit(1);
}

printf("Listening ...\n");
ret = listen(sockfd,5);
if(-1 == ret)
{
perror("listen");
exit(1);
}

while(1)
{
length = sizeof(client_addr);
fd[i] = accept(sockfd,(struct sockaddr*)&client_addr,&length);   //接收多个客户端的连接
if(-1 == fd[i])
{
perror("accept");
exit(1);
}

printf("Accept   %d,  Port   %d  \n",fd[i],server_addr.sin_port);

ret = pthread_create(&tid[i],NULL,Recv,(void *)&fd[i]);  //为每个客户端创建线程，来处理来自每个客户端发送来的信息
if(ret != 0)
{
perror("pthread_create");
exit(1);
}

i++;
}

close(sockfd);
return 0;

}

客户端

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>

pthread_t tid[2];
#define PORT 123

struct info
{
int  num;
char buf[100];
};

void *my_send(void *arg)
{
struct info SendBuff = {0};
int ret,oldtype;

pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS,&oldtype);

while(1)
{
scanf("%s  %d",SendBuff.buf,&SendBuff.num);

ret = send(*(int *)arg,&SendBuff,sizeof(SendBuff),0);
if(-1 == ret)
{
perror("send");
exit(1);
}
if(!strcmp(SendBuff.buf,"bye"))
{
close(*(int *)arg);
pthread_cancel(tid[1]);
break;
}
memset(&SendBuff,0,sizeof(SendBuff));
}

}

void *my_recv(void *arg)
{
struct info RecvBuff = {0};
int ret;

while(1)
{
ret = recv(*(int *)arg,&RecvBuff,sizeof(RecvBuff),0);
if(-1 == ret)
{
perror("recv");
exit(1);
}
printf("\t\t %s \n",RecvBuff.buf);
memset(&RecvBuff,0,sizeof(RecvBuff));
}

}

int main()
{
int sockfd,ret;

struct sockaddr_in server_addr;

sockfd = socket(PF_INET,SOCK_STREAM,0);
if(-1 == sockfd)
{
perror("socket");
exit(1);
}

memset(&server_addr,0,sizeof(server_addr));
server_addr.sin_family = PF_INET;
server_addr.sin_port = PORT;
server_addr.sin_addr.s_addr = inet_addr("127.0.0.1");

printf("Connecting ...\n");
ret = connect(sockfd,(struct sockaddr*)&server_addr,sizeof(server_addr));
if(-1 == ret)
{
perror("connect");
exit(1);
}

ret = pthread_create(&tid[0],NULL,my_send,(void *)&sockfd);
if(ret != 0)
{
perror("pthread_create");
exit(1);
}

ret = pthread_create(&tid[1],NULL,my_recv,(void *)&sockfd);
if(ret != 0)
{
perror("ptherad_create2");
exit(1);
}

pthread_join(tid[0],NULL);
pthread_join(tid[1],NULL);

close(sockfd);

return 0;
}

执行结果
服务器
Start ....
Binding ....
Listening ...
Accept   4,  Port   123
Accept   5,  Port   123
Recv form client 4 : hello
Recv form client 5 : hello

客户端1
Connecting ...
hello 5
hello
bye

客户端2
Connecting ...
hello
hello 4
bye