(Lianja) Accept TLS Connection with Client Authentication

Demonstrates how to accept a TLS connection requiring client authentication. This is the case where the TLS client sends a certificate. It is also known as "Two-Way SSL".

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// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

loListenSslSocket = createobject("CkSocket")

// An SSL/TLS server needs a digital certificate.  This example loads it from a PFX file.
// Note: This is the server's certificate.

loCert = createobject("CkCert")
// The 1st argument is the file path, the 2nd arg is the 
// PFX file's password:
llSuccess = loCert.LoadPfxFile("chilkat.pfx","test")
if (llSuccess <> .T.) then
    ? loCert.LastErrorText
    release loListenSslSocket
    release loCert
    return
endif

// To accept client client certificates in the TLS handshake,
// we must indicate a list of acceptable client certificate root CA DN's
// that are allowed.  (DN is an acronym for Distinguished Name.)
// Call AddSslAcceptableClientCaDn once for each acceptable CA DN.
// Here are a few examples so you can see the general format of a DN.
loListenSslSocket.AddSslAcceptableClientCaDn("C=SE, O=AddTrust AB, OU=AddTrust External TTP Network, CN=AddTrust External CA Root")
loListenSslSocket.AddSslAcceptableClientCaDn("O=Digital Signature Trust Co., CN=DST Root CA X3")

// Use the certificate:
llSuccess = loListenSslSocket.InitSslServer(loCert)
if (llSuccess <> .T.) then
    ? loListenSslSocket.LastErrorText
    release loListenSslSocket
    release loCert
    return
endif

// Bind and listen on a port:
lnMyPort = 8123
// Allow for a max of 5 queued connect requests.
lnBackLog = 5
llSuccess = loListenSslSocket.BindAndListen(lnMyPort,lnBackLog)
if (llSuccess <> .T.) then
    ? loListenSslSocket.LastErrorText
    release loListenSslSocket
    release loCert
    return
endif

// If accepting an SSL/TLS connection, the SSL handshake is part of the connection
// establishment process. This involves a few back-and-forth messages between the 
// client and server to establish algorithms and a shared key to create the secure 
// channel. The sending and receiving of these messages are governed by the 
// MaxReadIdleMs and MaxSendIdleMs properties. If these properties are set to 0 
// (and this is the default unless changed by your application), then the 
// AcceptNextConnection can hang indefinitely during the SSL handshake process. 
// Make sure these properties are set to appropriate values before calling AcceptNextConnection.

// Set a 10 second max for waiting to read/write.  This is for the SSL/TLS handshake establishment.
loListenSslSocket.MaxReadIdleMs = 10000
loListenSslSocket.MaxSendIdleMs = 10000

// Accept a single client connection and establish the secure SSL/TLS channel:

lnMaxWaitMillisec = 20000
loClientSock = loListenSslSocket.AcceptNextConnection(lnMaxWaitMillisec)
if (loListenSslSocket.LastMethodSuccess = .F.) then
    ? loListenSslSocket.LastErrorText
    release loListenSslSocket
    release loCert
    return
endif

// The client (in this example) is going to send a "Hello Server! -EOM-" 
// message.  Read it:
lcReceivedMsg = loClientSock.ReceiveUntilMatch("-EOM-")
if (loClientSock.LastMethodSuccess <> .T.) then
    ? loClientSock.LastErrorText
    release loListenSslSocket
    release loCert
    return
endif

? lcReceivedMsg

// Send a "Hello Client! -EOM-" message:
llSuccess = loClientSock.SendString("Hello Client! -EOM-")
if (llSuccess <> .T.) then
    ? loClientSock.LastErrorText
    release loListenSslSocket
    release loCert
    return
endif

// Close the connection with the client
// Wait a max of 20 seconds (20000 millsec)
llSuccess = loClientSock.Close(20000)

release loClientSock


release loListenSslSocket
release loCert