# %accept_starttls() function

The %accept_starttls function provides the ability to elevate an
 unsecured connection to a secured connection.

The %accept_starttls function is supported on D3 Windows and D3
 Linux.

## Syntax

```
code = %accept_starttls(fd, &address, certificate_file, privkey_file, &SSL);
```

## Parameter(s)

| fd | File descriptor of the local socket returned by a previous call to the FlashBASIC C function %accept(). |
| --- | --- |
| address | Originating address of the incoming call. This should be the same address used for the %accept() function. |
| certificate_file | Certificate file to be used by SSL_CTX_use_certificate_file. See your OpenSSL documentation for more information. For UNIX, you must specify the full path for the certificate file. |
| privkey_file | Private key file to be used by SSL_CTX_use_PrivateKey_file. See your OpenSSL documentation for more information. |
| SSL | Return value for the SSL handle. |

## Description

The Server, accepting connections from a Client, uses the %accept
 function for accepting an unsecured connection from a Client. Then, the Server uses the
 %accept_starttls function for elevating the received connection to
 a secured connection.

 The server code initially calls the %accept function to establish an
 unsecured connection. The Server then calls the %accept_starttls
 function to elevate the unsecured connection to a secured connection. This function
 negotiates with the Client by sending and receiving messages on the socket to specify 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 Server then
 calls the %accept_starttls function to elevate the unsecured
 connection to a secured connection.

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

 When using the %accept_starttls function, the sock
 and *addr* parameters that are returned by the
 %accept function must be passed to the
 %accept_starttls function in the *acceptfd* and
 *acceptaddr* parameters.

## Example(s)

**Example 1**

 **UNIX**: Server code for elevating unsecured connection to secured connection using
 the %accept and %accept_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
*
SOCKFD = %socket(AF$INET, SOCK$STREAM, 0)
IF SOCKFD = -1 THEN
CRT "Getting soxket failed"
STOP
END
*
HOST = "irv-vm-rh64b01"
CERT.FILE = "/home/pick/10.2/server.pem"
KEY.FILE = "/home/pick/10.2/ server.pem"
PORT = 9050
SSL = 0
ACCEPTADDR = 0
*

 Bind the socket to the ethernet port
 ------------------------------------
 bp=0
 bp=%bind( sockfd, AF$INET, INADDR$ANY, port )
 if bp<0 then
 errno=system(0)
 errmsg="Bind err=":errno
 crt &#39;bind failed error: &#39;:errmsg
 %close( sockfd)
 stop
 end
 *
 n=%listen( sockfd, 5 )
 if n<0 then
 errno=system(0)
 errmsg="Listen err=":errno
 crt &#39;listen failed error: &#39;:errmsg
 %close( sockfd)
 stop
 end
 ACCEPTADDR = STR(CHAR(0), 127) ;* sizeof(struct sockaddr_storage)
 ACCEPTFD = %accept(SOCKFD, &ACCEPTADDR, &PORT)
 IF ACCEPTFD < 0 THEN
 CRT "Accept failed"
 %close(SOCKFD)
 STOP
 END
 *
 RESULT = %accept_starttls(ACCEPTFD,&ACCEPTADDR,CERT.FILE,KEY.FILE,&SSL)
 IF RESULT < 0 THEN
 CRT "SSL connection to ":HOST:" failed"
 CRT "SSL accept failed"
 %close(SOCKFD)
 STOP
 END
 *
 %close(SOCKFD)
 *
 CRT "SSL accept successful"
 STOP
```

 **Example 2**

 **Windows**: Server code for elevating unsecured connection to secured connection
 using the %accept and %accept_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
INADDR$ANY = 0 ;
*
SOCKFD = %socket(AF$INET, SOCK$STREAM, 0)
IF SOCKFD = -1 THEN
CRT "Getting soxket failed"
STOP
END
*
HOST = "irv-vm-w10dd01"
CERT.FILE = "server.pem"
KEY.FILE = "server.pem"
PORT = 9050
SSL = 0
ACCEPTADDR = 0
*

 Bind the socket to the ethernet port
 ------------------------------------
 bp=%bind( sockfd, AF$INET, INADDR$ANY, port )
 if bp<0 then
 crt "Bind failed"
 %CLOSESOCKET( SOCKFD )
 STOP
 END
 *
 n=%listen( sockfd, 5 )
 if n<0 then
 CRT "Listen failed"
 %CLOSESOCKET( SOCKFD )
 STOP
 END
 *
 ACCEPTADDR = STR(CHAR(0), 127) ;* sizeof(struct sockaddr_storage)
 ACCEPTFD = %accept(SOCKFD, &ACCEPTADDR, &PORT)
 IF ACCEPTFD < 0 THEN
 CRT "Accept failed"
 %CLOSESOCKET( SOCKFD )
 STOP
 END
 *
 RESULT = %accept_starttls(ACCEPTFD,&ACCEPTADDR,CERT.FILE,KEY.FILE,&SSL)
 IF RESULT < 0 THEN
 CRT "SSL accept failed"
 %CLOSESOCKET( SOCKFD )
 STOP
 END
 *
 %CLOSESOCKET( SOCKFD )
 *
 CRT "SSL accept successful"
 STOP
```

## See also

- [%accept() function](https://d3codex.com/pickbasic-flashbasic/percent-accept-function/)
- [%accept_ssl() function](https://d3codex.com/pickbasic-flashbasic/percent-accept-ssl-function/)
- [%bind() function](https://d3codex.com/pickbasic-flashbasic/percent-bind-function/)
- [%close() function](https://d3codex.com/pickbasic-flashbasic/percent-close-function/)
- [%gethostid() function](https://d3codex.com/pickbasic-flashbasic/percent-gethostid-function/)
- [%listen() function](https://d3codex.com/pickbasic-flashbasic/percent-listen-function/)
- [%socket() function](https://d3codex.com/pickbasic-flashbasic/percent-socket-function/)

---
Source: https://d3codex.com/pickbasic-flashbasic/percent-accept-starttls-function/ - part of the D3Codex reference.