$bfconfig = Array (
'sitename' => '网站名称',
);

$mail = Array (
'state' => 1,
'server' => 'smtp.abc.com',
'port' => 25,
'auth' => 1,
'username' => 'admin@abc.com',
'password' => '123456',
'charset' => 'gbk',
'mailfrom' => 'admin@abc.com'
);

function sendmail($mail_to, $mail_subject, $mail_message) {

global $mail, $bfconfig;

date_default_timezone_set('PRC');

$mail_subject = '=?'.$mail['charset'].'?B?'.base64_encode($mail_subject).'?=';
$mail_message = chunk_split(base64_encode(preg_replace("/(^|(\r\n))(\.)/", "\1.\3", $mail_message)));

$headers .= "";
$headers .= "MIME-Version:1.0\r\n";
$headers .= "Content-type:text/html\r\n";
$headers .= "Content-Transfer-Encoding: base64\r\n";
$headers .= "From: ".$bfconfig['sitename']."<".$mail['mailfrom'].">\r\n";
$headers .= "Date: ".date("r")."\r\n";
list($msec, $sec) = explode(" ", microtime());
$headers .= "Message-ID: <".date("YmdHis", $sec).".".($msec * 1000000).".".$mail['mailfrom'].">\r\n";

if(!$fp = fsockopen($mail['server'], $mail['port'], $errno, $errstr, 30)) {
exit("CONNECT - Unable to connect to the SMTP server");
}

stream_set_blocking($fp, true);

$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != '220') {
exit("CONNECT - ".$lastmessage);
}

fputs($fp, ($mail['auth'] ? 'EHLO' : 'HELO')." befen\r\n");
$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != 220 && substr($lastmessage, 0, 3) != 250) {
exit("HELO/EHLO - ".$lastmessage);
}

while(1) {
if(substr($lastmessage, 3, 1) != '-' || empty($lastmessage)) {
break;
}
$lastmessage = fgets($fp, 512);
}

if($mail['auth']) {
fputs($fp, "AUTH LOGIN\r\n");
$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != 334) {
exit($lastmessage);
}

fputs($fp, base64_encode($mail['username'])."\r\n");
$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != 334) {
exit("AUTH LOGIN - ".$lastmessage);
}

fputs($fp, base64_encode($mail['password'])."\r\n");
$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != 235) {
exit("AUTH LOGIN - ".$lastmessage);
}

$email_from = $mail['mailfrom'];
}

fputs($fp, "MAIL FROM: <".preg_replace("/.*\<(.+?)\>.*/", "\\1", $email_from).">\r\n");
$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != 250) {
fputs($fp, "MAIL FROM: <".preg_replace("/.*\<(.+?)\>.*/", "\\1", $email_from).">\r\n");
$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != 250) {
exit("MAIL FROM - ".$lastmessage);
}
}

foreach(explode(',', $mail_to) as $touser) {
$touser = trim($touser);
if($touser) {
fputs($fp, "RCPT TO: <".preg_replace("/.*\<(.+?)\>.*/", "\\1", $touser).">\r\n");
$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != 250) {
fputs($fp, "RCPT TO: <".preg_replace("/.*\<(.+?)\>.*/", "\\1", $touser).">\r\n");
$lastmessage = fgets($fp, 512);
exit("RCPT TO - ".$lastmessage);
}
}
}

fputs($fp, "DATA\r\n");
$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != 354) {
exit("DATA - ".$lastmessage);
}

fputs($fp, $headers);
fputs($fp, "To: ".$mail_to."\r\n");
fputs($fp, "Subject: $mail_subject\r\n");
fputs($fp, "\r\n\r\n");
fputs($fp, "$mail_message\r\n.\r\n");
$lastmessage = fgets($fp, 512);
if(substr($lastmessage, 0, 3) != 250) {
exit("END - ".$lastmessage);
}

fputs($fp, "QUIT\r\n");

}