/*mail.h -- mail.h is a free header file which includes two functions to send an email via an SMTP Server.

 sendmail() Function usage :
  This Function has 6 Parameters :
   » first param : SMTP Server hostname;eg. "mx4.mail.yahoo.com"
   » Second param : name of the person who sends the EMail;eg. "Amir A"
   » Third param : sender's EMail address;eg. "Sender@Somewhere.com"
   » Fourth param : receiver's EMail address;eg. "Receiver@Somewhere.com"
   » fifth param : EMail Subject;eg. "Hi Dear Friend!"
   » sixth param : EMail Passage;eg. "I miss you!"

  Needed Header files :
   stdlib.h , winsock2.h and time.h.

  Return value :
   returns true on success and returns false on failure.for a better error handling Please 
   use WSAGetLastError() function right after the function call.

  Author :
   coded by Mobin Yazarlou.Secure_krnl «atsign» Yahoo «dot» com

*/

bool sendmail(char *,char *,char *,char *,char *,char *);
void dateheader(char *);

#define BUFFSIZE 256
#define CR 13
#define LF 10

 bool sendmail(char *smtphost,char *fromname,char *frommail,char *tomail,char *subject,char *message)
 {
  int result,bytes_sent,bytes_recv;
  char *buff,dheader[27];
  SOCKET mailsocket;
  WSADATA wsd;
  struct hostent *smtp;
  struct sockaddr_in smtpaddr;

   if(WSAStartup(MAKEWORD(2,0),&wsd) != 0)
    return false;

   smtp = gethostbyname(smtphost);
   if(!smtp)
    return false;

   mailsocket = socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
   if(mailsocket == INVALID_SOCKET)
    return false;

   smtpaddr.sin_family = AF_INET;
   smtpaddr.sin_addr.s_addr = *(unsigned long *)smtp->h_addr;
   smtpaddr.sin_port = htons(25);

   result = connect(mailsocket,(struct sockaddr *)&smtpaddr,sizeof(struct sockaddr));
   if(result == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }

   buff = (char *) malloc(BUFFSIZE);

   // Recv Mail Server Welcome Message
   bytes_recv = recv(mailsocket,buff,BUFFSIZE,0);
   if(bytes_recv == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send HELO Command
   sprintf(buff,"HELO yahoo.com%c%c",CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Recv Server Response
   bytes_recv = recv(mailsocket,buff,BUFFSIZE,0);
   if(bytes_recv == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send MAIL FROM: Command
   sprintf(buff,"MAIL FROM: <%s>%c%c",frommail,CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Recv Server Response
   bytes_recv = recv(mailsocket,buff,BUFFSIZE,0);
   if(bytes_recv == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send RCPT TO: Command
   sprintf(buff,"RCPT TO: <%s>%c%c",tomail,CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Recv Server Response
   bytes_recv = recv(mailsocket,buff,BUFFSIZE,0);
   if(bytes_recv == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send DATA Command
   sprintf(buff,"DATA%c%c",CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Recv Server Response
   bytes_recv = recv(mailsocket,buff,BUFFSIZE,0);
   if(bytes_recv == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send From Header
   sprintf(buff,"From: %s <%s>%c%c",fromname,frommail,CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send Subject Header
   sprintf(buff,"Subject: %s%c%c",subject,CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send MIME-Version Header
   sprintf(buff,"MIME-Version: 1.0%c%c",CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send Content-Type Header
   sprintf(buff,"Content-Type: text/plain; charset=\"utf-8\"%c%c",CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send Content-Transfer-Encoding Header
   sprintf(buff,"Content-Transfer-Encoding: 8bit%c%c",CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Send Date Header
   dateheader(dheader);
   sprintf(buff,"Date: %s%c%c",dheader,CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // End of Headers
   sprintf(buff,"%c%c%c%c",CR,LF,CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Now Send The Message
   buff = (char *) realloc(buff,strlen(message)+6);
   sprintf(buff,"%s%c%c.%c%c",message,CR,LF,CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',sizeof(buff));

   // Recv Server Response
   buff = (char *) realloc(buff,BUFFSIZE);
   bytes_recv = recv(mailsocket,buff,BUFFSIZE,0);
   if(bytes_recv == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   // Quit From Mail Server
   sprintf(buff,"QUIT%c%c",CR,LF);
   bytes_sent = send(mailsocket,buff,strlen(buff),0);
   if(bytes_sent == SOCKET_ERROR)
   {
    closesocket(mailsocket);
    WSACleanup();
    return false;
   }
   memset(buff,'\0',BUFFSIZE);

   closesocket(mailsocket);
   WSACleanup();

  return true;
 }

 void dateheader(char *header)
 {
  char mon[4];
  time_t timeinsec;
  struct tm *currentdt;

   timeinsec = time(NULL);
   currentdt = localtime(&timeinsec);

   switch(currentdt->tm_mon)
   {
    case 0 :
     strncpy(mon,"Jan\0",4);
     break;
    case 1 :
     strncpy(mon,"Feb\0",4);
     break;
    case 2 :
     strncpy(mon,"Mar\0",4);
     break;
    case 3 :
     strncpy(mon,"Apr\0",4);
     break;
    case 4 :
     strncpy(mon,"May\0",4);
     break;
    case 5 :
     strncpy(mon,"Jun\0",4);
     break;
    case 6 :
     strncpy(mon,"Jul\0",4);
     break;
    case 7 :
     strncpy(mon,"Aug\0",4);
     break;
    case 8 :
     strncpy(mon,"Sep\0",4);
     break;
    case 9 :
     strncpy(mon,"Oct\0",4);
     break;
    case 10 :
     strncpy(mon,"Nov\0",4);
     break;
    case 11 :
     strncpy(mon,"Dec\0",4);
     break;
   }

   sprintf(header,"%d %s %d %02d:%02d:%02d +0330",currentdt->tm_mday,
   mon,currentdt->tm_year+1900,currentdt->tm_hour,currentdt->tm_min,
   currentdt->tm_sec);

 }