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套接字编程(TCP协议)---附代码

程序员文章站 2022-04-29 23:48:04
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TCP的可靠性:1.应答确认   2.超时重传   3.滑动窗口

//套接字编程:客户端

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

int main()
{
    int sockfd = socket(AF_INET,SOCK_STREAM,0);  //SOCK_STREAM:流式套接字(TCP)
    assert(sockfd != -1);

    struct sockaddr_in saddr;  //确认链接服务器的信息:
    memset(&saddr,0,sizeof(saddr));  //清空
    saddr.sin_family = AF_INET;   //ipv4地址族
    saddr.sin_port = htons(6000);  //服务器端口
    saddr.sin_addr.s_addr = inet_addr("192.168.31.96");     //此处的ip为服务器的IP地址

    int res = connect(sockfd,(struct sockaddr*)&saddr,sizeof(saddr));  //发起链接服务器(三次握手)
    assert(res != -1);
    
    while(1)
    {
	char buff[128] = {0};
	printf("input:");
	fgets(buff,128,stdin);
	
	if(strncmp(buff,"end",3) == 0)
	{
	    break;
	}

	send(sockfd,buff,strlen(buff),0);

	memset(buff,0,128);
	recv(sockfd,buff,127,0);
	printf("buff = %s\n",buff);
    }
    
    close(sockfd);   //服务器recv返回0:

}
//套接字编程:服务器端

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

void *fun(void *arg)
{
    int c = (int)arg;
    while(1)
    {
	char buff[128] = {0};
	if(recv(c,buff,127,0) <= 0)
	{
	    break;
	}

	printf("buff(%d) = %s\n",c,buff);
	send(c,"ok",2,0);
    }
    close(c);
}


int main()
{
    int sockfd = socket(AF_INET,SOCK_STREAM,0);  //ipv4
    assert( sockfd != -1 );

    struct sockaddr_in saddr,caddr;
    memset(&saddr,0,sizeof(saddr));
    saddr.sin_family = AF_INET;
    saddr.sin_port = htons(6000);
    
    saddr.sin_addr.s_addr = inet_addr("192.168.31.96");

    int res = bind(sockfd,(struct sockaddr*)&saddr,sizeof(saddr));
    assert( res != -1);

    listen(sockfd,5);  //5:已完成三次握手队列长度(测试长度:n+1 = 6),不会超过MAX(128)
    
    while(1)
    {
	int len = sizeof(caddr);
	int c = accept(sockfd,(struct sockaddr*)&caddr,&len);

	if(c<0)
	{
	    continue;
	}

	printf("accept c = %d\n",c);

	pthread_t id;  //使用多线程,进行多用户同时链接服务端;
	pthread_create(&id,NULL,fun,(void *)c);  //创建线程

/*	while(1)
	{
	    char buff[128] = {0};
	    if(recv(c,buff,127,0) <= 0)   //等待客户端结束
	    {
		break;
	    }

	    printf("buff(%d) = %s\n",c,buff);
	    send(c,"ok",2,0);
	}
	close(c);
	printf("once client end!\n");
*/
  }

}