%connect_starttls() function

code = %connect_starttls(fd, &SSL);

The Client connecting to a Server uses the %connect function for establishing an unsecured connection to a server. Then, the Server uses the %connect_starttls function to elevate the unsecured connection to a secured connection.

The Client initially calls the %connect function to establish an unsecured connection, then calls the %connect_starttls function to elevate the unsecured connection to a secured connection. This function negotiates with the Server by sending and receiving messages on the socket to determine if the Server supports STARTTLS. If the Server supports STARTTLS and the Client chooses to use STARTTLS, the Client negotiates with the Server to use STARTTLS.

The %connect_starttls function provides similar functionality to the %connect_ssl function, except the embedded call to the %connect function has been removed. When calling the %connect_starttls function, the connection must have been previously established by using the %connect function.

Example 1

UNIX: Client code for connecting to mail server using the %connect and %connect_starttls functions:

cfunction socket.builtin
include dm,bp,includes sysid.inc
include dm,bp,unix.h socket.h
include dm,bp,unix.h errno.h
*
CRLF = CHAR(13):CHAR(10)
HELO = 'gmail.com'
*
SOCKFD = %socket(AF$INET, SOCK$STREAM, 0)
IF SOCKFD = -1 THEN
   CRT "Getting soxket failed"
   STOP
END
*
HOST = "smtp.gmail.com"
PORT = 587
SSL = 0
*
RESULT = %connect(SOCKFD,AF$INET,HOST,PORT)
IF RESULT < 0 THEN
   CRT "Connection to ":HOST:" failed"
   %close(SOCKFD)
   STOP
END
GOSUB DO.READ
*

SMTP PROTOCOL:
MSG = &#39;EHLO &#39;:HELO:CRLF
GOSUB DO.WRITE
GOSUB DO.READ
*
MSG = &#39;HELO &#39;:HELO:CRLF
GOSUB DO.WRITE
GOSUB DO.READ
*
MSG = &#39;STARTTLS&#39;:CRLF
GOSUB DO.WRITE
GOSUB DO.READ
*
RESULT = %connect_starttls(SOCKFD,&SSL)
IF RESULT < 0 THEN
   CRT "SSL connection to ":HOST:" failed"
   %close(SOCKFD)
   STOP
END
*
%close(SOCKFD)
*
CRT "SSL connection to :"HOST:" successful"
STOP
DO.READ:*
BUFFER = SPACE(4096)
LEN.BUFFER = LEN(BUFFER)
RESULT = %READ(SOCKFD, BUFFER, LEN.BUFFER)
IF RESULT < 0 THEN
   CRT "%READ FAILED RESULT : ":RESULT
   %close(SOCKFD)
   STOP
END
BYTES.READ = RESULT
CRT BUFFER[1, BYTES.READ]
RETURN
DO.WRITE:*
LEN.MSG = LEN(MSG)
RESULT = %WRITE(SOCKFD, MSG, LEN.MSG)

IF RESULT < 0 THEN
   CRT "%WRITE FAILED RESULT : ":RESULT
   %close(SOCKFD)
   STOP
END
RETURN

Example 2

Windows: Client code for connecting to mail server using the %connect and %connect_starttls functions:

cfunction socket.builtin
include dm,bp,includes sysid.inc
*
PLATFORM = SYSTEM(38)
WINDOWS.BASED = (PLATFORM<SYS$IMP> = SYS$NT)
AF$INET = 2 + 0; * internetwork: UDP, TCP, etc
SOCK$STREAM = 1 + 0; * stream socket
*
CRLF = CHAR(13):CHAR(10)
HELO = &#39;gmail.com&#39;
*
SOCKFD = %socket(AF$INET, SOCK$STREAM, 0)
IF SOCKFD = -1 THEN
   CRT "Getting soxket failed"
   STOP
END
*
HOST = "smtp.gmail.com"
PORT = 587
SSL = 0
*
RESULT = %connect(SOCKFD,AF$INET,(CHAR *)HOST,PORT)
IF RESULT < 0 THEN
   CRT "Connection to ":HOST:" failed"
   %CLOSESOCKET( SOCKFD )
   STOP
END
GOSUB DO.READ
*

SMTP PROTOCOL:
MSG = &#39;EHLO &#39;:HELO:CRLF
GOSUB DO.WRITE
GOSUB DO.READ
*
MSG = &#39;HELO &#39;:HELO:CRLF
GOSUB DO.WRITE
GOSUB DO.READ
*
MSG = &#39;STARTTLS&#39;:CRLF
GOSUB DO.WRITE
GOSUB DO.READ
*
RESULT = %connect_starttls(SOCKFD,&SSL)
IF RESULT < 0 THEN
   CRT "SSL connection to ":HOST:" failed"
   %CLOSESOCKET( SOCKFD )
   STOP
END
*
%CLOSESOCKET( SOCKFD )
*
CRT "SSL connection to :"HOST:" successful"
STOP
DO.READ:*
SOCKFD = SOCKFD + 0
BUFFER = SPACE(4096)
LEN.BUFFER = LEN(BUFFER)
RESULT = %RECV( SOCKFD, (CHAR *)BUFFER, LEN.BUFFER, 0)
IF RESULT < 0 THEN
   CRT "%READ FAILED RESULT : ":RESULT
   %CLOSESOCKET( SOCKFD )
   STOP
END
BYTES.READ = RESULT
CRT BUFFER[1, BYTES.READ]
RETURN
DO.WRITE:*
SOCKFD = SOCKFD + 0
LEN.MSG = LEN(MSG)
RESULT = %SEND( SOCKFD, (CHAR *)MSG, LEN.MSG, 0)
IF RESULT < 0 THEN
   CRT "%WRITE FAILED RESULT : ":RESULT
   %CLOSESOCKET( SOCKFD )
   STOP
END
RETURN