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FTP客戶端實現斷點續傳

編輯：C++入門知識

FTP客戶端是自己做的的第一個C項目，大二暑假做的。現在拿出來看看，當時只是初學者，暑假在學校一個人做了1個多星期。當代碼成功運行時，瞬間感到C的強大與編程的樂趣。不懂的朋友可以問我。

connect.c

[cpp]
#include <stdio.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>

#define SERV_IP "127.0.0.1"
#define SERV_PORT 21

char read_buf[1024];
char send_buf[1024];
int control_sock,n;

int main(int argc,char *argv[])
{
    /* 初始化socket */
    struct sockaddr_in servaddr;
    bzero(read_buf,sizeof(read_buf));
    bzero(send_buf,sizeof(send_buf));
    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    inet_pton(AF_INET,SERV_IP,&servaddr.sin_addr);
    servaddr.sin_port = htons(SERV_PORT);
    control_sock = socket(AF_INET, SOCK_STREAM, 0);

    /* 連接到服務器端 */
    connect(control_sock, (struct sockaddr *)&servaddr, sizeof(servaddr));

    /* 客戶端接收服務器端的一些歡迎信息 */
    n=read(control_sock, read_buf, sizeof(read_buf));
    if(n<0)
    {
        perror("read error");
        exit(1);
    }
    printf("From server %s\n",read_buf);
    login();

}

#include <stdio.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>

#define SERV_IP "127.0.0.1"
#define SERV_PORT 21

char read_buf[1024];
char send_buf[1024];
int control_sock,n;

int main(int argc,char *argv[])
{
/* 初始化socket */
struct sockaddr_in servaddr;
bzero(read_buf,sizeof(read_buf));
bzero(send_buf,sizeof(send_buf));
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family = AF_INET;
inet_pton(AF_INET,SERV_IP,&servaddr.sin_addr);
servaddr.sin_port = htons(SERV_PORT);
control_sock = socket(AF_INET, SOCK_STREAM, 0);

/* 連接到服務器端 */
connect(control_sock, (struct sockaddr *)&servaddr, sizeof(servaddr));

/* 客戶端接收服務器端的一些歡迎信息 */
n=read(control_sock, read_buf, sizeof(read_buf));
if(n<0)
{
perror("read error");
exit(1);
}
printf("From server %s\n",read_buf);
login();

}

[cpp]
include <stdio.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>

#define SERV_IP "127.0.0.1"
#define SERV_PORT 21

char read_buf[1024];
char send_buf[1024];
int control_sock,n;
void login()
{
        /* 命令 ”USER username\r\n” */
    strcpy(send_buf,"USER sunmeng\r\n");
    /*客戶端發送用戶名到服務器端 */
    n=write(control_sock,send_buf,strlen(send_buf));
    if(n<0)
    {
        perror("write username error");
        exit(1);
    }
    /* 客戶端接收服務器的響應碼和信息，正常為 ”331 User name okay, need password.” */
        bzero(send_buf,sizeof(send_buf));
    n=read(control_sock,send_buf,sizeof(send_buf));
    if(n<0)
    {
        perror("read error");
        exit(1);
    }
    printf("From server %s\n",send_buf);
        bzero(read_buf,sizeof(read_buf));
    strncpy(read_buf,send_buf,3);
       //   printf("%s",read_buf);
    if(strcmp(read_buf,"331")==0)
    {

        /* 命令 ”PASS password\r\n” */
        bzero(read_buf,sizeof(read_buf));
        bzero(send_buf,sizeof(send_buf));
        strcpy(send_buf,"PASS smeng1114\r\n");
        /* 客戶端發送密碼到服務器端 */
        n=write(control_sock,send_buf,strlen(send_buf));
        //printf("%d",strlen(send_buf));
        if(n<0)
        {
            perror("write username error");
            exit(1);
        }
        /* 客戶端接收服務器的響應碼和信息，正常為 ”230 User logged in, proceed.” */
        bzero(send_buf,sizeof(send_buf));
        n=read(control_sock,send_buf,sizeof(send_buf));
        if(n<0)
        {
            perror("read error");
            exit(1);
        }
        printf("From server %s\n",send_buf);
    }

    mode();
}

#include <stdio.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>

#define SERV_IP "127.0.0.1"
#define SERV_PORT 21

char read_buf[1024];
char send_buf[1024];
int control_sock,n;
void login()
{
        /* 命令 ”USER username\r\n” */
strcpy(send_buf,"USER sunmeng\r\n");
/*客戶端發送用戶名到服務器端 */
n=write(control_sock,send_buf,strlen(send_buf));
if(n<0)
{
  perror("write username error");
  exit(1);
}
/* 客戶端接收服務器的響應碼和信息，正常為 ”331 User name okay, need password.” */
      bzero(send_buf,sizeof(send_buf));
n=read(control_sock,send_buf,sizeof(send_buf));
if(n<0)
{
  perror("read error");
  exit(1);
}
printf("From server %s\n",send_buf);
        bzero(read_buf,sizeof(read_buf));
strncpy(read_buf,send_buf,3);
       // printf("%s",read_buf);
if(strcmp(read_buf,"331")==0)
{

  /* 命令 ”PASS password\r\n” */
  bzero(read_buf,sizeof(read_buf));
  bzero(send_buf,sizeof(send_buf));
  strcpy(send_buf,"PASS smeng1114\r\n");
  /* 客戶端發送密碼到服務器端 */
  n=write(control_sock,send_buf,strlen(send_buf));
  //printf("%d",strlen(send_buf));
  if(n<0)
  {
   perror("write username error");
   exit(1);
  }
  /* 客戶端接收服務器的響應碼和信息，正常為 ”230 User logged in, proceed.” */
  bzero(send_buf,sizeof(send_buf));
  n=read(control_sock,send_buf,sizeof(send_buf));
  if(n<0)
  {
   perror("read error");
   exit(1);
  }
  printf("From server %s\n",send_buf);
}

mode();
}

mode.c

[cpp]
#include <stdio.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>

#define SERV_IP "127.0.0.1"
#define SERV_PORT 21

char read_buf[1024];
char send_buf[1024];
char *p,*s;
int control_sock,data_sock,n,p1,p2;

void mode()
{
    /* 命令 ”PASV\r\n” */
    bzero(send_buf,sizeof(send_buf));
    strcpy(send_buf,"PASV\r\n");
    /* 客戶端告訴服務器用被動模式 */
    n=write(control_sock,send_buf,strlen(send_buf));
    //printf("%s\n",send_buf);
    if(n<0)
    {
        perror("write mode error");
        exit(1);
    }
    /*客戶端接收服務器的響應碼和新開的端口號，
     * 正常為 ”227 Entering passive mode (<h1,h2,h3,h4,p1,p2>)” */
    n=read(control_sock, read_buf, sizeof(read_buf));
    if(n<0)
    {
        perror("read mode error");
        exit(1);
    }
    printf("From server %s\n",read_buf);
    p=strtok(read_buf,",");
    //printf("%s\n",p);
    p=strtok(NULL,",");
    p=strtok(NULL,",");
    p=strtok(NULL,",");
    p=strtok(NULL,",");
    //printf("%s\n",p);
    s=strtok(NULL,")");
    //printf("%s\n",s);
    /*字符串轉換成整數*/
    p1=atoi(p);
    p2=atoi(s);
    data_sock=p1*256+p2;
        //printf("%d\n",data_sock);

    down();
}

#include <stdio.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>

#define SERV_IP "127.0.0.1"
#define SERV_PORT 21

char read_buf[1024];
char send_buf[1024];
char *p,*s;
int control_sock,data_sock,n,p1,p2;

void mode()
{
/* 命令 ”PASV\r\n” */
bzero(send_buf,sizeof(send_buf));
strcpy(send_buf,"PASV\r\n");
/* 客戶端告訴服務器用被動模式 */
n=write(control_sock,send_buf,strlen(send_buf));
//printf("%s\n",send_buf);
if(n<0)
{
  perror("write mode error");
  exit(1);
}
/*客戶端接收服務器的響應碼和新開的端口號，
* 正常為 ”227 Entering passive mode (<h1,h2,h3,h4,p1,p2>)” */
n=read(control_sock, read_buf, sizeof(read_buf));
if(n<0)
{
  perror("read mode error");
  exit(1);
}
printf("From server %s\n",read_buf);
p=strtok(read_buf,",");
//printf("%s\n",p);
p=strtok(NULL,",");
p=strtok(NULL,",");
p=strtok(NULL,",");
p=strtok(NULL,",");
//printf("%s\n",p);
s=strtok(NULL,")");
//printf("%s\n",s);
/*字符串轉換成整數*/
p1=atoi(p);
p2=atoi(s);
data_sock=p1*256+p2;
        //printf("%d\n",data_sock);

down();
}

down.c

[cpp]
#include <stdio.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#define SERV_IP "127.0.0.1"
#define SERV_PORT 21

char read_buf[100];
char send_buf[100];
int control_sock,data_sock,n;

void down()
{
    /* 連接服務器新開的數據端口 */
    struct sockaddr_in servaddr;
    bzero(read_buf,sizeof(read_buf));
    bzero(send_buf,sizeof(send_buf));

    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    inet_pton(AF_INET,SERV_IP,&servaddr.sin_addr);
    servaddr.sin_port = htons(data_sock);
    data_sock = socket(AF_INET, SOCK_STREAM, 0);
    connect(data_sock,(struct sockaddr *)&servaddr, sizeof(servaddr));
    // printf("%d\n",data_sock);
    /* 命令 ”CWD dirname\r\n” */
    strcpy(send_buf,"CWD /home/sunmeng/zhongbei/FTP\r\n");
    /* 客戶端發送命令改變工作目錄 */
    n=write(control_sock, send_buf, strlen(send_buf));
    if(n<0)
    {
        perror("write error");
        exit(1);
    }
    /* 客戶端接收服務器的響應碼和信息，正常為 ”250 Command okay.” */
    n=read(control_sock, read_buf, sizeof(read_buf));
    if(n<0)
    {
        perror("read error");
        exit(1);
    }
    printf("%s\n",read_buf);

    /* 命令 ”SIZE filename\r\n” */
    bzero(read_buf,sizeof(read_buf));
    bzero(send_buf,sizeof(send_buf));
    strcpy(send_buf,"SIZE ge.mp3\r\n");
    /* 客戶端發送命令從服務器端得到下載文件的大小 */
    n=write(control_sock, send_buf, strlen(send_buf));
    if(n<0)
    {
        perror("write error");
        exit(1);
    }
    /* 客戶端接收服務器的響應碼和信息，正常為 ”213 <size>” */
    n=read(control_sock, read_buf, sizeof(read_buf));
    if(n<0)
    {
        perror("read error");
        exit(1);
    }
    printf("%s\n",read_buf);

    /* 命令 ”RETR filename\r\n” */
    bzero(read_buf,sizeof(read_buf));
    bzero(send_buf,sizeof(send_buf));
    strcpy(send_buf,"RETR ge.mp3\r\n");
    /* 客戶端發送命令從服務器端下載文件 */
    n=write(control_sock, send_buf, strlen(send_buf));
    if(n<0)
    {
        perror("write error");
        exit(1);
    }
    /* 客戶端接收服務器的響應碼和信息，正常為 ”150 Opening data connection.” */
    //printf("%d\n",data_sock);
    /*read阻塞只有匿名用戶才能下載*/
    n=read(control_sock, read_buf, sizeof(read_buf));
    if(n<0)
    {
        perror("read error");
        exit(1);
    }
    printf("%s\n",read_buf);
    /* 客戶端創建文件 */
    int file=1;;
    n = open("gequ.mp3", O_RDWR|O_CREAT, 0666);
    while(file>0) {
        /* 客戶端通過數據連接從服務器接收文件內容 */
        bzero(read_buf,sizeof(read_buf));
        file =read(data_sock, read_buf, sizeof(read_buf));
        if(file<0)
        {
            perror("create file error");
            exit(1);
        }
        /* 客戶端寫文件 */
        file = write(n, read_buf, strlen(read_buf));
        if(file<0)
        {
            perror("write error");
            exit(1);
        }

    }
    /* 客戶端關閉文件 */
    close(n);

}