man/InitSocketTcti.3.in

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.TH InitSocketTcti 3 "JUNE 2017" Intel "TPM2 Software Stack"
.SH NAME
InitSocketTcti \- Initialization function for the Microsoft TPM simulator TCTI library.
.SH SYNOPSIS
.B #include <tcti/tcti_socket.h>
.sp
.BI "typedef int (*TCTI_LOG_CALLBACK)( void " "*data" ", printf_type" "type" ", const char " "*format" ", "..." ");"
.sp
.nf
typedef struct {
    const char *hostname;
    uint16_t port;
    TCTI_LOG_CALLBACK logCallback;
    TCTI_LOG_BUFFER_CALLBACK logBufferCallback;
    void *logData;
} TCTI_SOCKET_CONF;
.fi
.sp
.BI "TSS2_RC InitSocketTcti (TSS2_TCTI_CONTEXT " "*tctiContext" ", size_t " "*contextSize" ", const TCTI_SOCKET_CONF " "*config" ", const uint8_t " "serverSockets" ");"

.sp
The
.BR  InitSocketTcti ()
function initializes a TCTI context used to communicate with the Microsoft TPM
simulator.
.SH DESCRIPTION
.BR InitSocketTcti ()
attempts to initialize a caller allocated
.I tcti_context
of size
.I size
using caller provided configuration information from
.I config
\&. Since the
.I tcti_context
must be a caller allocated buffer, the caller needs to know the size required
by the TCTI library. The minimum size of this context can be discovered by
providing
.BR NULL
for the
.I tcti_context
and a non-
.BR NULL
.I size
parameter. The initialization function will then populate the
.I size
parameter with the minimum size of the
.I tcti_context
buffer. The caller must then allocate a buffer of this size (or larger) and
call
.B InitSocketTcti ()
again providing the newly allocated
.I tcti_context
and the size of this context in the
.I size
parameter. This patterm is common to all TCTI initialization functions. We
provide an example of this pattern using the
.BR InitSocketTcti ()
function in the section titled
.B EXAMPLE.
.sp
The
.I config
parameter is a reference to an instance of the
.B TCTI_SOCKET_CONF
structure. The
.I hostname
member of this structure is a C string that contains the hostname or IPv4
address of the Microsoft TPM simulator. The
.I port
member is an unsigned 16 bit integer containing the port number for the
simulator command / response port. The simulator listens for \*(lqplatform
commands\*(rq on
.I port+1
and so an additional connection will be made to this port. The
.I logCallback
member is a pointer to a callback function that will be called by the
socket TCTI. This is expected to be a
.I printf
like function. The
.I logBufferCallback
mamber is a pointer to a call back function that will be invoked by the
socket TCTI before a command buffer is transmitted or after a resposne buffer
is received. This is expected to be a
.I printf
like function. The
.I logData
member is a void pointer that may be used to pass user data to the
.I logCallback
and
.I logBufferCallback
functions on each invocation.
.sp
The
.I serverSockets
parameter should always be 0 for client code.
.sp
Once initialized, the TCTI context returned exposes the Trusted Computing
Group (TCG) defined API for the lowest level communication with the TPM.
Using this API the caller can exchange (send / receive) TPM2 command and
respons buffers with the Microsoft TPM simulator. In nearly all cases however,
the caller will initialize a context using this funnction before passing the
context to a higher level API like the System API (SAPI), and then never touch
it again.
.sp
For a more thorough discussion of the TCTI API see the \*(lqTSS System Level
API and TPM Command Transmission Interface Specification\*(rq as published by
the TCG:
\%https://trustedcomputinggroup.org/tss-system-level-api-tpm-command-transmission-interface-specification/
.SH RETURN VALUE
A successful call to
.BR InitSocketTcti ()
will return
.B TSS2_RC_SUCCESS.
An unsuccessful call will produce a response code described in section
.B ERRORS.
.SH ERRORS
.B TSS2_TCTI_RC_BAD_VALUE
is returned if both the
.I tcti_context
and the
.I size
parameters are NULL, or if the
.I config
parameter is NULL.
.SH EXAMPLE
Logging functions:
.sp
.nf
int DebugPrintfCallback (void *data, printf_type type, const char *format, ...)
{
    va_list args;
    int rval = 0;

    va_start( args, format );
    rval = vprintf( format, args );
    va_end (args);

    return rval;
}
void DebugPrintBuffer (printf_type type, UINT8 *buffer, UINT32 length)
{
    UINT32  i;

    for( i = 0; i < length; i++ )
    {
        if( ( i % 16 ) == 0 ) {
            printf ("\n");
        }

        printf ("%2.2x ", buffer[i] );
    }
    printf ("\n\n");
}
.fi
.sp
TCTI initialization fragment:
.sp
.nf
#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <tcti/tcti_socket.h>

TSS2_RC rc;
TSS2_TCTI_CONTEXT *tcti_context;
size_t size;
TCTI_SOCKET_CONF conf = {
    .hostname          = "127.0.0.1",
    .port              = 2321,
    .logCallback       = DebugPrintfCallback,
    .logBufferCallback = DebugPrintBuffer,
    .logData           = NULL,
};

rc = InitSocketTcti (NULL, &size, NULL, 0);
if (rc != TSS2_RC_SUCCESS) {
    fprintf (stderr, "Failed to get allocation size for tabrmd TCTI "
             " context: 0x%" PRIx32 "\n", rc);
    exit (EXIT_FAILURE);
}
tcti_context = calloc (1, size);
if (tcti_context == NULL) {
    fprintf (stderr, "Allocation for TCTI context failed: %s\n",
             strerror (errno));
    exit (EXIT_FAILURE);
}
rc = InitSocketTcti (&tcti_context, &size, &conf, 0);
if (rc != TSS2_RC_SUCCESS) {
    fprintf (stderr, "Failed to initialize tabrmd TCTI context: "
             "0x%" PRIx32 "\n", rc);
    free (tcti_context);
    exit (EXIT_FAILURE);
}
.fi