(C) 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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#include <C_CkSocket.h>
#include <C_CkCert.h>

void ChilkatSample(void)
    {
    HCkSocket listenSslSocket;
    HCkCert cert;
    BOOL success;
    int myPort;
    int backLog;
    HCkSocket clientSock;
    int maxWaitMillisec;
    const char *receivedMsg;

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

    listenSslSocket = CkSocket_Create();

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

    cert = CkCert_Create();
    // The 1st argument is the file path, the 2nd arg is the 
    // PFX file's password:
    success = CkCert_LoadPfxFile(cert,"chilkat.pfx","test");
    if (success != TRUE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkSocket_Dispose(listenSslSocket);
        CkCert_Dispose(cert);
        return;
    }

    // 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.
    CkSocket_AddSslAcceptableClientCaDn(listenSslSocket,"C=SE, O=AddTrust AB, OU=AddTrust External TTP Network, CN=AddTrust External CA Root");
    CkSocket_AddSslAcceptableClientCaDn(listenSslSocket,"O=Digital Signature Trust Co., CN=DST Root CA X3");

    // Use the certificate:
    success = CkSocket_InitSslServer(listenSslSocket,cert);
    if (success != TRUE) {
        printf("%s\n",CkSocket_lastErrorText(listenSslSocket));
        CkSocket_Dispose(listenSslSocket);
        CkCert_Dispose(cert);
        return;
    }

    // Bind and listen on a port:
    myPort = 8123;
    // Allow for a max of 5 queued connect requests.
    backLog = 5;
    success = CkSocket_BindAndListen(listenSslSocket,myPort,backLog);
    if (success != TRUE) {
        printf("%s\n",CkSocket_lastErrorText(listenSslSocket));
        CkSocket_Dispose(listenSslSocket);
        CkCert_Dispose(cert);
        return;
    }

    // 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.
    CkSocket_putMaxReadIdleMs(listenSslSocket,10000);
    CkSocket_putMaxSendIdleMs(listenSslSocket,10000);

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

    maxWaitMillisec = 20000;
    clientSock = CkSocket_AcceptNextConnection(listenSslSocket,maxWaitMillisec);
    if (CkSocket_getLastMethodSuccess(listenSslSocket) == FALSE) {
        printf("%s\n",CkSocket_lastErrorText(listenSslSocket));
        CkSocket_Dispose(listenSslSocket);
        CkCert_Dispose(cert);
        return;
    }

    // The client (in this example) is going to send a "Hello Server! -EOM-" 
    // message.  Read it:
    receivedMsg = CkSocket_receiveUntilMatch(clientSock,"-EOM-");
    if (CkSocket_getLastMethodSuccess(clientSock) != TRUE) {
        printf("%s\n",CkSocket_lastErrorText(clientSock));
        CkSocket_Dispose(listenSslSocket);
        CkCert_Dispose(cert);
        return;
    }

    printf("%s\n",receivedMsg);

    // Send a "Hello Client! -EOM-" message:
    success = CkSocket_SendString(clientSock,"Hello Client! -EOM-");
    if (success != TRUE) {
        printf("%s\n",CkSocket_lastErrorText(clientSock));
        CkSocket_Dispose(listenSslSocket);
        CkCert_Dispose(cert);
        return;
    }

    // Close the connection with the client
    // Wait a max of 20 seconds (20000 millsec)
    success = CkSocket_Close(clientSock,20000);

    CkSocket_Dispose(clientSock);


    CkSocket_Dispose(listenSslSocket);
    CkCert_Dispose(cert);

    }