Linux下UDP通讯开发

服务器部分

#include"protocol.h"

#include"sys/types.h"

#include"sys/socket.h"

#include"string.h"

#include"stdio.h"

#include"stdlib.h"

#include"netinet/in.h"

#include"fcntl.h"

int main()

{

int sockfd;

int writefd,readfd;

struct sockaddr_in server,client;

char recvbuf[1000];

char readbuf[1000];

char sendbuf[1000];

char writebuf[1000];

struct protocol *pro,*repro;

int checkcode;

int run =1;

socklen_t len;

server.sin_addr.s_addr=inet_addr("127.0.1");

server.sin_port=htons(12345);

server.sin_family=AF_INET;

len =sizeof(server);

sockfd = socket(AF_INET,SOCK_DGRAM,0);

bind(sockfd,(struct sockaddr*)&server,len);

while(run)

{

recvfrom(sockfd,recvbuf,sizeof(recvbuf),0,(struct sockaddr*)&client,&len);

repro = (struct protocol*)malloc(sizeof(struct protocol));

pro = (struct protocol*)malloc(sizeof(struct protocol));

memcpy(repro,recvbuf,sizeof(recvbuf));

int select;

switch(repro->command)

{

case SHUTDOWN:

pro->command=SHUTDOWN;
pro->no=checkcode++;
strcpy(pro->buf,"nullptr");
pro->len=strlen("nullptr");
run=0;

break;

case DOWNLOAD:

pro->no=++repro->no;

        if(-1==(readfd=open(repro->buf,O_RDWR,0666)))
{
pro->command=NO;
printf("yes---------->\n");
}
else
{
pro->command=YES;
printf("no:---------->\n");
}
strcpy(pro->buf,"nullptr");
pro->len=strlen("nullptr");
break;

case UPLOAD:
printf("client want to upload a file ,do you allow?\n");
printf("      1 START    other no \n");scanf("%d",&select);
if(select==1)
{
pro->command=START;
pro->no=checkcode++;
strcpy(pro->buf,"nullptr");
pro->len= sizeof("nullptr");
writefd=open(repro->buf,O_RDWR|O_CREAT,0666);
}

          else
 {

pro->command=NO;
pro->no=checkcode++;
strcpy(pro->buf,"nullptr");
pro->len= sizeof("nullptr");

 }

break;

case START:

read(readfd,readbuf,sizeof(readbuf));
pro->command=CONTENT;
pro->no=checkcode++;
strcpy(pro->buf,readbuf);
pro->len=strlen(readbuf);
memcpy(sendbuf,pro,INFOLEN);

        sendto(sockfd,sendbuf,sizeof(sendbuf),0,(struct sockaddr *)&client,len);
printf("wait to finish download.........\n");

        free(pro);

pro = (struct protocol*)malloc(sizeof(struct protocol));
pro->command=END;
pro->no=checkcode++;
strcpy(pro->buf,"EDN");
pro->len=strlen("EDN");
break;

case CONTENT:

write(writefd,repro->buf,sizeof(repro->buf));
close(writefd);
printf("upload will be finish\n");
break;
case END:

     printf("\t  upload is ok \n");
break;
default :
printf("default command :%d\n",repro->command);
pro->command=100;
pro->no=0;
strcpy(pro->buf,"connect");
pro->len=strlen("connect");
break;

}

memcpy(sendbuf,pro,INFOLEN);

        sendto(sockfd,sendbuf,sizeof(sendbuf),0,(struct sockaddr *)&client,len);
printf("\tcommand-->%d\n\tlen------>%d\n\tno------->%d\n\tbuf------>%s\n",
pro->command,pro->len,pro->no,pro->buf);

        free(pro);
free(repro);

}

close(sockfd);

return 0;

}

客户端部分

#include"protocol.h"

#include"sys/types.h"

#include"sys/socket.h"

#include"string.h"

#include"stdio.h"

#include"stdlib.h"

#include"netinet/in.h"

#include"fcntl.h"

int main()

{

int sockfd;

int run=1;

int slip=1;

int writefd;

int readfd;

struct sockaddr_in server,client;

char recvbuf[1000];

char readbuf[1000];

char writebuf[1000];

struct protocol *pro,*repro;

char sendbuf[INFOLEN];

char filename[20];

socklen_t len;

server.sin_addr.s_addr=inet_addr("127.0.1");

server.sin_port=htons(12345);

server.sin_family=AF_INET;

len =sizeof(server);

sockfd = socket(AF_INET,SOCK_DGRAM,0);

 int checkcode=0;

 pro=(struct protocol*)malloc(sizeof(struct protocol));

char inputbuf[1000];

//first connect 
 pro->command=100;
 pro->no=0;
 strcpy(pro->buf,"nullptr");
   pro->len=strlen("nullptr");
 memcpy(sendbuf,pro,INFOLEN);

      sendto(sockfd,sendbuf,sizeof(sendbuf),0,(struct sockaddr *)&server,len);
 printf("\t  connect .............\n");

      free(pro);  

while(run)

{

   repro = (struct protocol*)malloc(sizeof(struct protocol));

   pro=(struct protocol*)malloc(sizeof(struct protocol));

   recvfrom(sockfd,recvbuf,sizeof(recvbuf),0,(struct sockaddr*)&server,&len);

   memcpy(repro,recvbuf,sizeof(recvbuf));

switch(repro->command)

{

case YES:

     //download  yes

 pro->command=START;
 pro->no=checkcode++;
 strcpy(pro->buf,"nullptr");
     pro->len=strlen("nullptr");
 memcpy(sendbuf,pro,INFOLEN);

          sendto(sockfd,sendbuf,sizeof(sendbuf),0,(struct sockaddr *)&server,len);
 printf("\t download is yes     \n");

          free(pro);
 slip=0;

     pro=(struct protocol*)malloc(sizeof(struct protocol));

      break;

case CONTENT:

writefd=open(filename,O_RDWR|O_CREAT,0666);
write(writefd,repro->buf,strlen(repro->buf));
close(writefd);
printf("download is ok cloent\n");
break;
case NO:
//download no

  printf("\thave no such file\n");
break;

case START:

    //upload start
readfd=open(filename,O_RDWR|O_CREAT,0666);
read(readfd,readbuf,sizeof(readbuf));
 pro->command=CONTENT;
 pro->no=checkcode++;
 strcpy(pro->buf,readbuf);
     pro->len=strlen(readbuf);
 memcpy(sendbuf,pro,INFOLEN);

          sendto(sockfd,sendbuf,sizeof(sendbuf),0,(struct sockaddr *)&server,len);
 printf("\t  upload is start    \n");

          free(pro);
pro=(struct protocol*)malloc(sizeof(struct protocol));

  
 pro->command=END;
 pro->no=checkcode++;
 strcpy(pro->buf,"END");
     pro->len=strlen("END");
 memcpy(sendbuf,pro,INFOLEN);

          sendto(sockfd,sendbuf,sizeof(sendbuf),0,(struct sockaddr *)&server,len);
break;

case SHUTDOWN:

    //service had shutdown

run =0;
break;
case END:
printf("\t download is ok \n");
   slip=1;
break;

default :
printf("default  ............%d \n",repro->command);
break;

}

free(repro);

if(run+slip>=2)

{

printf("\t*********************************************************\n");

printf("\t***********************    Client   *********************\n");

printf("\t*********************************************************\n");

printf("\t***********************  0 SHUTDOWN    ******************\n");

printf("\t***********************  1 DOWNLOAD    ******************\n");

printf("\t***********************  3 UPLOAD      ******************\n");

printf("\t*********************************************************\n");

printf("please input a num:\t");int n;scanf("%d",&n);

switch(n)

{

case SHUTDOWN:

pro->command=SHUTDOWN;
pro->no=checkcode++;
strcpy(pro->buf,"nullptr");
pro->len=strlen("nullptr");

break;

case DOWNLOAD:
pro->command=DOWNLOAD;
pro->no=checkcode++;

        printf("\t please input the name of the download-file:\t");scanf("%s",&inputbuf);
strcpy(pro->buf,inputbuf);

strcpy(filename,inputbuf);
pro->len=strlen(inputbuf);
break;

case UPLOAD:

pro->command=UPLOAD;
pro->no=checkcode++;

        printf("\t please input the name of the upload-file):\t");scanf("%s",&inputbuf);
strcpy(pro->buf,inputbuf);
strcpy(filename,inputbuf);
pro->len=strlen(inputbuf);
break;

default :
break;

}

memcpy(sendbuf,pro,INFOLEN);

        sendto(sockfd,sendbuf,sizeof(sendbuf),0,(struct sockaddr *)&server,len);
printf("\tcommand-->%d\n\tlen------>%d\n\tno------->%d\n\tbuf------>%s\n",
pro->command,pro->len,pro->no,pro->buf);

}

}

close(sockfd);
return 0;

}

协议结构体

#ifndef _protocol

#define _protocol

#define INFOLEN 1000

#define SHUTDOWN 0

#define DOWNLOAD 1

#define UPLOAD 2

#define YES 3

#define NO 4

#define START 5

#define END 6

#define CONTENT 7

#define OK 8

struct protocol

{
int command;
int len;  //length of buf
int no;
char buf[INFOLEN];

};

#endif