email.c

嵌入式linux下的Email客户端

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


#define PORT 25 //smtp port
#define SIZE 41984 
//define mail commands
#define EHLO 0
#define AUTH 1
#define USER 2
#define PASS 3
#define MAIL 4
#define RCPT 5
#define DATA 6
#define CONT 7
#define QUIT 8

void base64enc(const char *,char *);

int email()
{
int sockfd;
struct sockaddr_in server_addr;
struct hostent *server_ip;
int numbytes=0,i=0;
char username[20]="";//mail username
char passwd[20]="";//mail passwd

//buff store data by recv(),
char buff[512]="",tmp[4]="";
char * p;
char alarmcontext[SIZE]="";
char ch;
int ret=0;//function return
FILE *f_open,*f_write, *f_jpg;
char *msg[9]={""};
char *n_return[9]={""}; //return number

msg[EHLO]="ehlo smtp.163.com\n";
msg[AUTH]="auth login\n";
base64enc("alarm_01",username);
strcat(username,"\n");
msg[USER]=username;
base64enc("123456",passwd);
strcat(passwd,"\n");
msg[PASS]=passwd;
msg[MAIL]="mail from:<[e-mail]>\n";
msg[RCPT]="rcpt to:<[e-mail]>\n";
msg[DATA]="data\n";
msg[QUIT]="quit\n";

n_return[EHLO]="250";
n_return[AUTH]="334";
n_return[USER]="334";
n_return[PASS]="235";
n_return[MAIL]="250";
n_return[RCPT]="250";
n_return[DATA]="354";
n_return[CONT]="250";

/*jpegfiel en64 to 123.txt*/
en64_out("123.jpg", "456.txt");
/*-----------------------------
read from 123.txt, add it to msg[CONT]
-----------------------------*/
if((f_open=fopen("123.txt","r")) ==NULL)
{
	perror("fopen error");
	return(-1);
}

p=alarmcontext;
while ((ch = getc(f_open)) != EOF)
       	{
		*p=ch;
		p++;
	}
if((f_jpg=fopen("456.txt","r")) ==NULL)
{
	perror("fopen error");
	return(-1);
}
while ((ch = getc(f_jpg)) != EOF)
       	{
		*p=ch;
		p++;
	}
		
*p=0;
strncat(alarmcontext,"\n.\n",3);//cat "\n.\n" to data 
msg[CONT]=alarmcontext; 
//printf("msg[CONT]:\n%s\n", msg[CONT]);

fclose(f_jpg);
fclose(f_open);


/*------------------------------
connect server,and send command
------------------------------*/
//because the host connect to internet by dail,
//so,it is possiabe that host have not connected when it start
//then we sleep 3 seconds,and try again until the host connect to internet
//we know the connection status by gethostbyname(),but this way is not always correct

while((server_ip=gethostbyname("smtp.163.com"))==NULL)
{
herror("gethostbyname error");
sleep(3);
}

//create a socket
if((sockfd=socket(AF_INET,SOCK_STREAM,0))==-1)
{
	perror("socket error");
	return(-1);
}

//address information
server_addr.sin_family=AF_INET;//host byte order
server_addr.sin_port=htons(PORT);//short,network byte order
server_addr.sin_addr=*((struct in_addr *)server_ip->h_addr);//server ip
bzero(&(server_addr.sin_zero),8);//zero the rest of struct

//connect server
if(connect(sockfd,(struct sockaddr *)&server_addr,sizeof(struct sockaddr))==-1)
{
	perror("connect error");
	return(-1);
}
//if connect success,server return "220"
if((numbytes=recv(sockfd,buff,SIZE,0))==-1)
{
	perror("recv error");
	return(-1);
} 

//clean tmp
for(i=0;i<4;i++)
	tmp[i]='\0';
strncpy(tmp,buff,3);
if(strcmp(tmp,"220")!=0)
	return (-1);

//send msgs. if any step has a mistake,the "while" will be breaked,then send "quit" to end connection 
printf("begin send msgs\n");
i=EHLO;
while(i<QUIT)
{
	if((numbytes=send(sockfd, msg[i], strlen(msg[i]), 0))==-1)
	{
		perror("send error");
		break;
	}
	//sleep(1);we dont have to use it,because recv() can choke itself until it received data
	if((numbytes=recv(sockfd,buff,SIZE,0)) == -1)
	{
		perror("recv error");
		break;
	} 
	strncpy(tmp,buff,3);

//printf("command:%s\n",msg);
//printf("return buff:%s\n",buff);
//printf("should return:%s\n",n_return);

if(strcmp(tmp, n_return[i])==0) 
	i++;
else
	break;
}

//send quit to end mail connection
if((numbytes=send(sockfd,msg[QUIT],strlen(msg[QUIT]),0))==-1)
{
	perror("send error");
	return(-1);
}


close(sockfd);
return (0);
}

/*-------------------------
base64 encode function
-------------------------*/
void base64enc(const char *instr, char *outstr)
{ 
    char *table="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    int   instr_len=0,i=0,j=0,pad=0; 
    unsigned char buf1[4]="", buf2[4]=""; 
   
    instr_len=strlen(instr);    
    pad=instr_len%3;
    
    for(i=0; i<instr_len; i +=3) 
        { 
         if(i == instr_len-pad)
                  strncpy(buf1,&instr[i],pad);
            else
               strncpy(buf1,&instr[i],3);
  
            buf2[0] = buf1[0] >> 2; 
            buf2[1] = ((buf1[0] & 0x03) << 4) | (buf1[1] >> 4); 
            buf2[2] = ((buf1[1] & 0x0f) << 2) | (buf1[2] >> 6); 
            buf2[3] = buf1[2] & 0x3f; 
            for(j=0;j<4;j++) 
                  buf2[j]=table[buf2[j]];
               
         if(i==instr_len-pad)
               for(j=3;j>pad;j--)
                     buf2[j]='=';
       	strncat(outstr, buf2, 4);
      }
   
}