Unicode C

Socket Convert Existing TCP Connection to SSL/TLS

Demonstrates the Chilkat Socket ConvertToSsl method. Unicode C

#include <C_CkSocketW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSocketW sock;
    BOOL useTls;
    int port;
    int maxWaitMs;

    success = FALSE;

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

    sock = CkSocketW_Create();

    //  --------------------------------------------------------------------
    //  This example uses the public TCP/TLS echo service at https://tcpbin.com/
    //  --------------------------------------------------------------------

    //  The echo server at tcpbin.com expects to receive TCP connections on port 4242, and TLS connections on port 4243.
    //  We could simply connect to port 4243 using TLS like this.
    //  However, further below, this example shows how to initially make a TCP connection, and then convert the connection to TLS.
    useTls = TRUE;
    port = 4243;
    maxWaitMs = 5000;
    success = CkSocketW_Connect(sock,L"tcpbin.com",port,useTls,maxWaitMs);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(sock));
        CkSocketW_Dispose(sock);
        return;
    }

    //  OK, we have a TLS connection.
    //  Note: The server chooses the TLS protocol version. 
    //  We can see the version of the TLS connection that was established:
    wprintf(L"TLS version: %s\n",CkSocketW_tlsVersion(sock));

    CkSocketW_Close(sock,maxWaitMs);

    //  ---------------------------------------------------------------------
    //  Now we'll do the same, except first we connect to port 4243 using TCP,
    //  and then convert the connection to TLS.
    //  
    //  This may seem pointless, and it is for the case w/ this server.  However, there could be situations
    //  where you're interacting with a server of some kind where there is a need to convert to/from TLS.
    //  (This is common internal to many protocols, such as SMTP, IMAP, FTP, etc., and it is often called "explicit" SSL/TLS)

    //  Connect again, except this time useTls is FALSE, so we only have a simple TCP connection after this call.
    useTls = FALSE;
    success = CkSocketW_Connect(sock,L"tcpbin.com",port,useTls,maxWaitMs);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(sock));
        CkSocketW_Dispose(sock);
        return;
    }

    //  Convert the existing TCP connection to TLS.
    //  (The method name uses "SSL" because long ago, at the time of initial development, TLS 1.0 did not yet exist.)
    success = CkSocketW_ConvertToSsl(sock);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(sock));
        CkSocketW_Dispose(sock);
        return;
    }

    //  OK, we now have a TLS connection.
    //  Again, we can see the TLS version:
    wprintf(L"TLS version: %s\n",CkSocketW_tlsVersion(sock));

    CkSocketW_Close(sock,maxWaitMs);


    CkSocketW_Dispose(sock);

    }