UDP模拟FTP程序

程序使用

1.运行服务端 ./ftp_server 出现ftp> 

输入 get filename1.txt (filename1.txt为接收文件的名字）

2.运行客户端，如果是本机 ./fpt 127.0.0.1,出现ftp>

 输入 put filename2.txt （filename2.txt）为要发送的文件。

void get_cmd(char **p)
{
    fgets(*p,100,stdin);
}
/*将带有空格的字符串s进行解析，存放到cmd字符串数组中*/

int split_string(char *s,char _cmd[][100])
{
    char *p = s;
    int i = 0;
    int j = 0;
    while(*p != '\n')
    {
        if(*p == ' ')
        {
            _cmd[i][j]='\0';
            i++;
            j = 0;
            p++;
            /*处理多个空格的情况*/
            while(*p == ' ')
            {
                p++;
            }
        }
        else
        {
            _cmd[i][j] = *p;
            p++;
            j++;
        }
    }
    return i+1;
}

2.服务端ftp_server.c

/*
 UDP 传输方式实现FTP，服务器段
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <sys/types.h>
#include "cmd.h"

int port = 8888;
int sockfd;
int bind_ret; /*绑定的返回值*/
//void get_cmd(char **p);/*从控制台获取命令*/
//int split_string(char *s,char _cmd[][100]); /*解析命令*/
struct sockaddr_in adr_inet;/*服务器端地址信息*/
void bind_ip();/*绑定服务器地址信息*/
void get_file(char *_filename);/*接受文件*/
int main()
{
    char *s; /*从控制台获得的命令*/
    char (*cmd)[100];/*分割后的命令*/
    int len;/*参数个数*/
    s = (char *)malloc(sizeof(char)*100);
        cmd = (char (*)[])malloc(sizeof(s)*10);

    bind_ip();
    printf("ftp>");
    get_cmd(&s);
    split_string(s,cmd);

    while(strcmp(cmd[0],"quit") != 0)
    {
        if(strcmp(cmd[0],"get") == 0)
        {
            char filename[100];
            strcpy(filename,cmd[1]);
            if(!fork())
            {
                get_file(filename);
                exit(0);
            }

        }
        get_cmd(&s);
        len = split_string(s,cmd);

    }

    close(sockfd);
    exit(0);

}
/*绑定服务器地址信息*/
void bind_ip()
{
    /*建立IP地址*/
    adr_inet.sin_family = AF_INET;
    adr_inet.sin_port = htons(port);
    adr_inet.sin_addr.s_addr = htonl(INADDR_ANY);
    bzero(&(adr_inet.sin_zero),8);
    /*建立socket*/
    sockfd = socket(AF_INET,SOCK_DGRAM,0);
    if(sockfd == -1)
    {
        perror("socket error!");
        exit(1);
    }

    /*绑定socket*/
    bind_ret = bind(sockfd,(struct sockaddr *)&adr_inet,sizeof(adr_inet));

    if(bind_ret == -1)
    {
        perror("bind error!");
        exit(1);
    }

}

/*接受文件*/
void get_file(char *_filename)
{
    int len;
    char buf[256];
    struct sockaddr_in adr_clnt;/*用来保存客户端地址信息*/
    len = sizeof(adr_clnt);

    /*创建一个文件，用来保存传送过来的文件*/
    FILE *fp;
    fp = fopen(_filename,"w+");
    if(fp == NULL)
    {
        perror("create file error!");
        exit(1);
    }
    printf("Waiting client to download!\n");
    while(1)
    {
        /*接受传来的信息*/
        bind_ret = recvfrom(sockfd,buf,sizeof(buf),0,(struct sockaddr*)&adr_clnt,&len);
        if(bind_ret < 0)
        {
            perror("recvfrom error!");
            exit(1);
        }
        buf[bind_ret] = '\0';
        if(strncmp(buf,"stop",4) != 0)
        {
            //printf("receive :%s\n",buf);
            fputs(buf,fp);
        }

        if(strncmp(buf,"stop",4) == 0)
        {
            printf("Finished!\n");
            break;
        }
    }
    close(fp);
    printf("ftp>");
}

3.客户端ftp.c

/*
 UDP 传输方式实现FTP,客户段
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
#include <malloc.h>
#include "cmd.h"

int port = 8888;
int sockfd;/*套接字描述符*/
struct sockaddr_in adr_srvr;/*服务器地址信息*/

//void get_cmd(char **p);/*从控制台获取命令*/
int connect_to_server(char * ip);/*连接服务器*/
//int split_string(char *s,char _cmd[][100]); /*解析命令*/
void send_file(char *filename);/*发送文件*/
int main(int argc,char **argv)
{

    connect_to_server(argv[1]);
    //connect_to_server("127.0.0.1");
    char *s; /*从控制台获得的命令*/
    char (*cmd)[100];/*分割后的命令*/
    int len;/*输入的参数个数*/
    s = (char *)malloc(sizeof(char)*100);
        cmd = (char (*)[])malloc(sizeof(s)*10);
    printf("ftp>");

    /*注意不能用get_cmd(s),因为p存放的不是“s存放的地址”，而是
      s本身的地址。详细查看“彻底搞定C指针”的第4篇。
      */
    get_cmd(&s);
    len = split_string(s,cmd);

    while(strcmp(cmd[0],"quit") != 0)
    {
        if(strcmp(cmd[0],"put") == 0)
        {
            char filename[100];
            strcpy(filename,cmd[1]);
            send_file(filename);
        }

        printf("ftp>");
        get_cmd(&s);
        len = split_string(s,cmd);
    }

    close(sockfd);
    exit(0);

}
int connect_to_server(char * ip)
{
    struct hostent *host;
    printf("Connect to server……\n");
    /*建立IP地址*/
    host = gethostbyname(ip);
    if(host == NULL)
    {
        herror("gethostbyname error!");
        exit(1);
    }

    /*初始化服务器地址信息*/
    adr_srvr.sin_family = AF_INET;
    adr_srvr.sin_port = htons(port);
    adr_srvr.sin_addr = *((struct in_addr *)host->h_addr);
    bzero(&(adr_srvr.sin_zero),8);

    /*建立socket*/
    sockfd = socket(AF_INET,SOCK_DGRAM,0);
    if(sockfd == -1)
    {
        perror("socket error!");
        exit(1);
    }
    return 1;
}

void send_file(char *_filename)
{
    FILE *fp;
    int send_ret;
    char buf[256];
    char str1[80];
    fp = fopen(_filename,"r");
    if(fp == NULL)
    {
        perror("open failed!");
        return ;
    }
    //读取数据传递给UDPserver
    printf("Sending……\n");
    while(fgets(str1,256,fp)!=NULL)
    {
          //printf("%s\n",str1);
        sprintf(buf,"%s",str1);

        send_ret = sendto(sockfd,buf,sizeof(buf),0,(struct sockaddr*)&adr_srvr,sizeof(adr_srvr));

        if(send_ret < 0)
        {
            perror("sendto error!");
            return;
        }
    }
    printf("Finished!\n");
    sprintf(buf,"stop\n");

    send_ret = sendto(sockfd,buf,sizeof(buf),0,(struct sockaddr*)&adr_srvr,sizeof(adr_srvr));

    if(send_ret < 0)
    {
        perror("sendto error!");
        return ;
    }
    fclose(fp);
}