UDP实现文件内容传输
##程序可以直接复制使用，不受环境影响；
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该设计框图左边实现文件循环写入并读取，读取数据存放于buf中，通过sendto()发送出去；
右边实现内容接收并保存到文件中，由recvfrom()接收暂存于buf缓冲区，write()将buf 内容存入文件，
read()进行读取验证。如果是只需要发送与接收功能：左边去掉write()部分，右边去掉read()
（不对信息进行验证）部分。
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client 端口实现发送
/*client端实现对文件的追加写入以及发送；
*提示用户手动输入发送文件的路径与名称；
*文件必须是已经存在的；（后期修改自动创建文件）
*如果不需要向文件写入buf内容，可以将WriteInfo()函数功能去掉；
*/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define PORT 8886
#define BUF_SIZE 1024
//#define FILE_PATH "./udpFile.txt"
int UdpClient(char path1[BUF_SIZE],int n1);
int WriteInfo(char path0[BUF_SIZE],int n0);
/*一维数组作为参数传递，手动输入发送文件文件路径*/
int main(void)
{
int n;
char path[BUF_SIZE];
n = sizeof(path)/sizeof(char);
printf("Please input send file path and name:\n");
scanf("%s",path);
UdpClient(path,n);
return 0;
}
/*<----------------从当前位置偏移2位，写入buf内容到文件----------------------->*/
int WriteInfo(char path0[BUF_SIZE],int n0)
{
int fd,len;
char buf[]="No xx:UDP send file content and save in receive file!";
fd=open(path0,O_WRONLY|O_APPEND);
if(fd<0)
{
perror("Write open file error ");
return 1;
}
else if(write(fd,buf,53)<0)
{
perror("write message failed!\n");
return 1;
}
else if(lseek(fd,4,SEEK_CUR)<0)/*当前位置偏移4位更改内容*/
{
perror("Write lseek error!");
return 1;
}
else
{
printf("Write message to file sucess!\n");
}
close(fd);
len=strlen(buf); /*接收端第0次位空白*/
return len;
}
/*<----------------发送buff缓存的内容，循环一次偏移一次----------------------->*/
int UdpClient(char path1[BUF_SIZE],int n1)
{
int i=0,StepSize,Steplen=0;
int fd;
struct sockaddr_in s_addr; //套接字地址结构
int sock; //套接字描述符
int addr_len; //地址结构长度
int len; //发送字节长度
char buff[BUF_SIZE];
/* 创建数据报模式的套接字 */
if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) { //SOCK_DGRAM表示数据包套接字UDP
perror("socket error");
exit(errno);
}
else
printf("create socket successful.\n\r");
/* 设置对方地址和端口信息 */
s_addr.sin_family = AF_INET; //地址族
s_addr.sin_port = htons(PORT);
s_addr.sin_addr.s_addr = htonl(INADDR_ANY);//inet_addr(argv[1]);
addr_len = sizeof(s_addr); //地址结构长度
/*从客户端的buff缓冲区中发送消息到地址结构为s_addr的远端机器*/
printf("-----------------------------%d------------------------------\n",i);
while(1)
{
/*write and Read file message to buff*/
StepSize=WriteInfo(path1,n1);
fd=open(path1,O_RDWR); /*以读写方式打开，O_RDNOLY 只读方式存在问题*/
if(fd<0)
{
perror("Read Open file error");
return 1;
}
else if(lseek(fd,Steplen,SEEK_SET)<0) /*步长+strlen(buf),循环一次读取新写入的内容*/
{
perror("Read lseek error!");
return 1;
}
else
printf("Read open file sucess!\n");
if(read(fd,buff,53)<0)
{
perror("read file content failed ");
return 1;
}
else
printf("Read file information save to buff sucessful!\n");
close(fd);
len = sendto(sock, buff, sizeof(buff), 0,(struct sockaddr *) &s_addr, addr_len);
if (len < 0) { /*如果发送失败*/
printf("\n\rsend error.\n\r");
return 1;
}
printf("Send buff info successful!\n\r");
Steplen+=StepSize;
printf("StepSize=%d\tSteplen=%d\n",StepSize,Steplen);
sleep(2);
printf("-----------------------------%d------------------------------\n",++i);
}
close(sock);
return 0;
}
###############################################################################
server端口实现接收
/*server端实现对文件的接收并保存到指定文件中；
*提示用户手动输入保存文件的路径与名称；
*文件必须是已经存在的；（后期修改自动创建文件）
*保存后在进行读取打印，确认信息无误。
*/
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#define PORT 8886
#define BUF_SIZE 1024
//#define FILE_PATH "./udpSave.txt"
int WriteFileInfo(char buff[BUF_SIZE],int Steplen,char path[BUF_SIZE],int n);
int ReadFileInfo(int Steplen,char path[BUF_SIZE],int n);
int UdpServerRecv(char path[BUF_SIZE],int n);
/*一维数组作为参数传递，手动输入保存文件路径*/
int main(void) /*main(int argc, char **argv)*/
{
int n;
char path[BUF_SIZE];
n = sizeof(path)/sizeof(char);
printf("Please input save file path and name:\n");
scanf("%s",path);
UdpServerRecv(path,n);
return 0;
}
int UdpServerRecv(char path[BUF_SIZE],int n)
{
struct sockaddr_in s_addr; //服务器地址结构，IPV4对应的是sockaddr_in结构体
struct sockaddr_in c_addr; //客户端地址结构
int sock,i=0; //套接字描述符
socklen_t addr_len; //地址结构长度
int len,StepSize,Steplen=0; //接收到的消息字节数
char buff[BUF_SIZE ]; //存放接收消息的缓冲区
if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) {
perror("socket");
exit(errno);
}
else
printf("create socket successful.\n\r");
memset(&s_addr, 0, sizeof(struct sockaddr_in));
s_addr.sin_family = AF_INET;
s_addr.sin_port = htons(PORT); //把16位值从主机字节序转换成网络字节序
s_addr.sin_addr.s_addr = INADDR_ANY; //输入本机IP地址
if ((bind(sock, (struct sockaddr *) &s_addr, sizeof(s_addr))) == -1) {
perror("bind error");
exit(errno);
}
else
printf("bind address to socket successfuly.\n\r");
addr_len = sizeof(c_addr);
printf("-------------------------------------%d---------------------------------------\n",i);
while (1) {
len = recvfrom(sock, buff, sizeof(buff) - 1, 0,(struct sockaddr *) &c_addr, &addr_len);
if (len < 0) {
perror("recvfrom error");
exit(errno);
}
StepSize=strlen(buff)-1;
buff[len] = '\0';
printf("Received from a remote computer:%s ;The port number is:%d\nBuf Message is: \n%s\n\r",inet_ntoa(c_addr.sin_addr), ntohs(c_addr.sin_port), buff);
WriteFileInfo(buff,Steplen,path,n);
ReadFileInfo(Steplen,path,n);
Steplen+=StepSize;
printf("StepSize=%d\tSteplen=%d\n",StepSize,Steplen);
sleep(2);
printf("-------------------------------------%d---------------------------------------\n",++i);
}
close(sock);
return 0;
}
int WriteFileInfo(char buff[BUF_SIZE],int Steplen,char path[BUF_SIZE],int n)
{
int fd;
fd= open(path,O_WRONLY); //"O_WRONLY"
if(fd<0)
{
perror("Write open file error");
return 1;
}
else if(lseek(fd,Steplen,SEEK_SET)<0) /*步长+strlen(buf),循环一次读取新写入的内容*/
{
perror("Read lseek error!");
return 1;
}
else if(write(fd,buff,53)<0)
{
perror("write file error");
return 1;
}
else
printf("write sucessful!\n");
close(fd);
return 0;
}
int ReadFileInfo(int Steplen,char path[BUF_SIZE],int n)
{
int fd;
char buf[BUF_SIZE];
fd=open(path,O_RDWR); /*以读写方式打开，O_RDNOLY 只读方式存在问题*/
if(fd<0)
{
perror("Read open file error");
return 1;
}
else if(lseek(fd,Steplen,SEEK_SET)<0) /*步长+strlen(buf),循环一次读取新写入的内容*/
{
perror("Read lseek error!");
return 1;
}
else if(read(fd,buf,53)<0)
{
perror("Read file error");
return 1;
}
else
printf("Read info on file sucessful!\n");
close(fd);
printf("The save info is : %s\n",buf);
return 0;
}
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