网络编程 day5 (UDP上传updown)

Mr Chris_LI

已于 2023-05-20 20:56:49 修改

阅读量109

点赞数

分类专栏：网络编程文章标签：网络 udp linux

于 2023-05-20 20:28:51 首次发布

本文链接：https://blog.youkuaiyun.com/Hellomino_/article/details/130785487

版权

网络编程专栏收录该内容

13 篇文章

订阅专栏

该代码示例展示了如何使用C语言进行UDP套接字编程，包括创建套接字、绑定IP和端口、发送和接收数据。程序实现了从命令行参数指定的文件读取内容并上传到服务器的功能。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<strings.h>
#include<unistd.h>
#include<errno.h>
#include<fcntl.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>

#define NUM 10
#define ERR_MSG(msg) do{\
	printf("line: %d\n",__LINE__);\
	perror(msg);\
}while(0)
#define PORT  69         //端口号的网络字节序  1024～49151
#define SerIP "192.168.1.15"  //ifconfig查看本机IP  (ipv4)
int main(int argc, const char *argv[])
{
	//创建报式套接字
	int sfd=socket(AF_INET,SOCK_DGRAM,0);
	if(sfd<0)
	{
		ERR_MSG("socket");
		return -1;
	}

	//填充服务器自身的地址信息结构体
	//真实的地址信息结构体根据地址族制定AF_INET ; man 7 ip
	struct sockaddr_in Sersin; 
	Sersin.sin_family  = AF_INET;            //必须填充AF_INET
	Sersin.sin_port   = htons(PORT);        //端口号的网络字节序  1024～49151
	Sersin.sin_addr.s_addr = inet_addr(SerIP);  //ifconfig查看本机IP
	//将SerIP地址和端口号绑定到制定的套接字文件描述符上
	/*
	   if(bind(sfd,(struct sockaddr *)&Sersin, sizeof(Sersin)) < 0)
	   {
	   ERR_MSG("bind");
	   return -1;
	   }
	   printf("bind success __%d__\n",__LINE__);


	   struct sockaddr_in Usrsin; 
	   Usrsin.sin_family  = AF_INET;            //必须填充AF_INET
	   Usrsin.sin_port   = htons(6666);        //端口号的网络字节序  1024～49151
	   Usrsin.sin_addr.s_addr = inet_addr(UsrIP);  //ifconfig查看本机IP

	   if(connect(sfd,(struct sockaddr *)&Usrsin,sizeof(Usrsin))<0)
	   {
	   ERR_MSG("connect");
	   return -1;
	   }
	   printf("connect success\n");

*/
	char buf[516]="";
	char arr[32]="";
	/*

	   short* ptr1 = (short *)buf;
	 *ptr1 = htons(2);

	 char * ptr2 = buf+2;
	 strcpy(ptr2,argv[1]);

	 char *ptr3 = ptr2+strlen(ptr2);

	 char *ptr4 = ptr3+1;
	 strcpy(ptr4,"octet");
	 */
	int size=sprintf(arr,"%c%c%s%c%s%c",0,2,argv[1],0,"octet",0);
	printf("arr_size = %d\n",size);
	struct sockaddr_in cin; 
	socklen_t len;

	if(sendto(sfd,arr,size,0,(struct sockaddr*)&Sersin,sizeof(Sersin))<0)
	{
		ERR_MSG("sendto");
		return -1;
	}
	printf("发送成功\n");

	int resw=0;
	int count=0;
	ssize_t res = 0;	
	const char *s=argv[1];
	int fr=open(argv[1],O_RDONLY);
	unsigned short i=0;
	if(0>fr)
	{
		ERR_MSG("open");
		return -1;
	}
	printf("open success\n");
	*(short *)(buf+2) = htons(0);

	while(1)
	{
		//if(htons((*(short *)(buf+2)))!=i) continue;
		while(1)
		{
			//接收数据
			bzero(buf,sizeof(buf));
			if(recvfrom(sfd,buf,sizeof(buf),0,(struct sockaddr *)&cin,&len)<0)
			{
				ERR_MSG("recvfrom");
				return -1;
			}
			printf("[%d]:[%d]  ",ntohs(*(short *)buf),ntohs(*(short *)(buf+2)));
			fflush(stdout);
			if((ntohs(*(unsigned short *)(buf+2)))==i)
				break;
		}
		// 发送数据
		if(buf[1]==4)
		{
			printf("i= %d  %d\n",i,__LINE__);

			bzero(buf,sizeof(buf));
			sprintf(buf,"%c%c%c%c",0,3,0,++i);
			res=read(fr,buf+4,512);
			if(res<0)
			{
				ERR_MSG("read");
				return -1;
			}
			if(res==0)
			{
				printf("上传完成\n");
				break;
			}
			if(sendto(sfd,buf,res+4,0,(struct sockaddr *)&cin,len)<0)
			{
				ERR_MSG("sendto");
				return -1;
			}

		}
		else if(htons(*buf) == htons(5))
		{
			printf("download error:[%d]  %s\n",*(short *)buf,buf+2);
			return -1;
		}

	}
	return 0;
}