linux网络编程-UDP实现文件的传输

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>

#define PORT 4000
#define BUFLEN 1024             //每次接收的数据

#define ERR_EXIT(m) \
do				\
{				\
perror(m);	\
exit(1);	\
}while(0);

int main()
{
int myfd,hefd;
struct sockaddr_in seraddr,cliaddr;
char readbuf[BUFLEN] = {0};
int addrlen;
int ret;
FILE *fp;
unsigned int count = 0;
int writen = 0;
if(-1 == (myfd = socket(PF_INET,SOCK_DGRAM,0)))     //产生UDP套接字
ERR_EXIT("socket");

bzero(&seraddr,sizeof(seraddr));
seraddr.sin_family  = AF_INET;
seraddr.sin_port = htons(PORT);
seraddr.sin_addr.s_addr = htonl(INADDR_ANY);

if(-1 == bind(myfd,(struct sockaddr*)&seraddr,sizeof(seraddr)))   //绑定套接字
ERR_EXIT("bind");

fp = fopen("/home/albert/fly_copy.txt","w");   //打开文件，如果文件不存在，则生成新的空文件，此文件用于接收从客户端发来的数据
addrlen = sizeof(struct sockaddr);

while(1)
{
memset(readbuf,0,BUFLEN);             //清空缓存
if( -1 == (ret = recvfrom(myfd,readbuf,BUFLEN,0,(struct sockaddr*)&cliaddr,&addrlen)))
ERR_EXIT("recvfrom");
if(9 == ret)                               //当客户端发完数据后，再发一个结束标志的字符串给服务器端，服务器端收到这个标志后
{				           //说明全部数据接收完毕，则关闭文件指针，如果不这么做，不关闭文件指针，则最后会有部分数据不能够正确写入
if(! strncasecmp(readbuf,"11close11",9))  //结束字符串，自己定义即可
{
fclose(fp);			//关闭文件指针
printf("close file\n");
break;                       //跳出循环
}
}
writen = fwrite(readbuf,1,ret,fp);         //把收到的数据写入文件
if(writen != ret)
{
exit(1);
}
printf("receive ret = %d\n",ret);         //后面这三行主要用于检验服务器端是否能够全部接收客户端的数据，只是检查用
printf("count = %d\n",count);
count++;
}

close(myfd);
return 0;
}

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

#define PORT 4000
#define IP "127.0.0.1"
#define BUFLEN 512

int main()
{
int clifd;
struct sockaddr_in seraddr;
char writebuf[BUFLEN];
int ret;
FILE *fp;
FILE *wfp;
unsigned int count = 0;
int readn;
long file_len = 0;
long len = 0;
if(-1 == (clifd = socket(AF_INET,SOCK_DGRAM,0)))
{
perror("socket");
exit(1);
}

bzero(&seraddr,sizeof(seraddr));

seraddr.sin_family = AF_INET;
seraddr.sin_port = htons(PORT);
seraddr.sin_addr.s_addr = inet_addr(IP);

fp = fopen("/home/albert/Fly.txt","r");    //打开文件，只读
fseek(fp,0L,SEEK_END);                   //把文件指针定位到最后
file_len = ftell(fp);                   //计算出文件有多少个字节
fseek(fp,0L,SEEK_SET);                  //把文件指针定位到开始的位置
len = file_len;
memset(writebuf,0,BUFLEN);

while(!feof(fp))
{
readn = fread(writebuf,1,BUFLEN,fp);
if(BUFLEN > file_len)
{
if(-1 == (ret = sendto(clifd,writebuf,file_len,0,(struct sockaddr*)&seraddr,sizeof(struct sockaddr))))
{
perror("sendto");
exit(1);
}
}
else
{
if(-1 == (ret = sendto(clifd,writebuf,BUFLEN,0,(struct sockaddr*)&seraddr,sizeof(struct sockaddr))))
{
perror("sendto");
exit(1);
}
file_len -= BUFLEN;
}
memset(writebuf,0,BUFLEN);
printf("ret = %d\n",ret);
printf("count = %u\n",count);
count++;
}
/*	while(( readn = (fread(writebuf,1,BUFLEN,fp)) )> 0)
{
if(-1 == (ret = sendto(clifd,writebuf,BUFLEN,0,(struct sockaddr*)&seraddr,sizeof(struct sockaddr))))
{
perror("sendto");
exit(1);
}
//		memset(writebuf,0,BUFLEN);
printf("ret = %d\n",ret);
printf("count = %u\n",count);
count++;
memset(writebuf,0,BUFLEN);
}
*/
printf("break readn = %d\n",readn);
printf("break ret = %d\n",ret);
printf("file_len = %ld\n",len);
printf("read file_len = %ld\n",file_len);
char notice[9] = "11close11";
if(-1 == (ret = sendto(clifd,notice,9,0,(struct sockaddr*)&seraddr,sizeof(struct sockaddr))))
{
exit(1);
}
close(clifd);
fclose(fp);
return 0;
}