Oracle UTL_SMTP closing connection - oracle

Question

This is example of procedure that I'm using to send mail
BEGIN
l_mail_conn := UTL_SMTP.OPEN_CONNECTION(c_mailhost, c_port);
UTL_SMTP.HELO(l_mail_conn, c_mailhost);
UTL_SMTP.MAIL(l_mail_conn, p_sender);
UTL_SMTP.RCPT(l_mail_conn, p_recipient);
--Create HEADER
l_head := 'MIME-Version: 1.0' || UTL_TCP.crlf
|| 'To: ' || p_recipient || UTL_TCP.crlf
|| 'From: ' || p_sender || UTL_TCP.crlf
|| 'Subject: ' || p_subject || UTL_TCP.crlf
|| 'Content-Type: multipart/mixed; boundary="' || g_mime_bound || '"' || UTL_TCP.crlf
--|| UTL_TCP.crlf
|| 'This is a multi-part message in MIME format.' || UTL_TCP.crlf
|| '--' || g_mime_bound || UTL_TCP.crlf
|| 'Content-Type: ' || p_type || UTL_TCP.crlf || UTL_TCP.crlf
--|| 'Content-Transfer-Encoding: quoted-printable ' || UTL_TCP.crlf || UTL_TCP.crlf
;
--DBMS_OUTPUT.PUT_LINE(l_head);
--Write HEADER
DBMS_LOB.CREATETEMPORARY(l_body, false, 10);
DBMS_LOB.WRITE(l_body, LENGTH(l_head), 1, l_head);
--DBMS_OUTPUT.PUT_LINE(l_body);
--Write BODY
l_offset := DBMS_LOB.GETLENGTH(l_body) + 1;
DBMS_LOB.WRITE(l_body, LENGTH(p_data), l_offset, p_data);
--DBMS_OUTPUT.PUT_LINE(l_body);
l_offset := 1;
UTL_SMTP.OPEN_DATA(l_mail_conn);
WHILE l_offset < DBMS_LOB.GETLENGTH(l_body)
LOOP
UTL_SMTP.WRITE_RAW_DATA(l_mail_conn, UTL_RAW.CAST_TO_RAW(DBMS_LOB.SUBSTR(l_body, l_ammount, l_offset)));
l_offset := l_offset + l_ammount;
l_ammount := LEAST(1900, DBMS_LOB.GETLENGTH(l_body) - l_ammount);
END LOOP;
--Clear DATA
UTL_SMTP.CLOSE_DATA(l_mail_conn);
UTL_SMTP.QUIT(l_mail_conn);
DBMS_LOB.FREETEMPORARY(l_body);
END;
And it works as intended, problem is with closing connections. My best guess is that if procedure breaks somewhere between opening connection and closing it, connection stays open. When that happens enough times, I get
ERROR: ORA-30678: too many open connections
ORA-06512: at "SYS.UTL_TCP", line 17
ORA-06512: at "SYS.UTL_TCP", line 267
ORA-06512: at "SYS.UTL_SMTP", line 161
ORA-06512: at "SYS.UTL_SMTP", line 197
So I've decided to add closing connection to my EXCEPTION block. But while I was testing, I realized that I can't run UTL_SMTP.QUIT(l_mail_conn) if connection is not open, if I try it I get
ORA-29278: SMTP transient error: 421 Service not available
ORA-06512: at "SYS.UTL_SMTP", line 54
ORA-06512: at "SYS.UTL_SMTP", line 138
ORA-06512: at "SYS.UTL_SMTP", line 699
So then I found out there is function called NOOP I can use to determine if connection is open or not, so I tried that one, and it works some times, if I call it before connection is open, I get
421
Service not available
And if I call it after connection is open, I get
250
Ok
But if I try to call it after while loop or inside it (before data is closed), procedure breaks again with following error
ORA-29277: invalid SMTP operation
ORA-06512: at "SYS.UTL_SMTP", line 80
ORA-06512: at "SYS.UTL_SMTP", line 210
ORA-06512: at "SYS.UTL_SMTP", line 677
As a temporary fix, I simply added utl_tcp.close_all_connections; in my exception block, but it's not something I would like to do (cause it could potentially break other procedured using UTL_SMTP at the same time)
So I just need a way to make sure connection is closed no matter what happens. Does anyone knows how it should be done?
Thanks