tcp.c

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/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Protocol services - TCP layer
   Copyright (C) Matthew Chapman <matthewc.unsw.edu.au> 1999-2008
   Copyright 2005-2011 Peter Astrand <astrand@cendio.se> for Cendio AB
   Copyright 2012-2013 Henrik Andersson <hean01@cendio.se> for Cendio AB

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "precomp.h"
#ifdef WITH_SSL
#include <sspi.h>
#include <schannel.h>
#endif

#ifdef _WIN32
#define socklen_t int
#define TCP_CLOSE(_sck) closesocket(_sck)
#define TCP_STRERROR "tcp error"
#define TCP_SLEEP(_n) Sleep(_n)
#define TCP_BLOCKS (WSAGetLastError() == WSAEWOULDBLOCK)
#else /* _WIN32 */
#define TCP_CLOSE(_sck) close(_sck)
#define TCP_STRERROR strerror(errno)
#define TCP_SLEEP(_n) sleep(_n)
#define TCP_BLOCKS (errno == EWOULDBLOCK)
#endif /* _WIN32 */

#ifndef INADDR_NONE
#define INADDR_NONE ((unsigned long) -1)
#endif

#ifdef WITH_SCARD
#define STREAM_COUNT 8
#else
#define STREAM_COUNT 1
#endif

#ifdef WITH_SSL
typedef struct
{
    CtxtHandle ssl_ctx;
    SecPkgContext_StreamSizes ssl_sizes;
    char *ssl_buf;
    char *extra_buf;
    size_t extra_len;
    char *peek_msg;
    char *peek_msg_mem;
    size_t peek_len;
    DWORD security_flags;
} netconn_t;
static char * g_ssl_server = NULL;
static RD_BOOL g_ssl_initialized = False;
static RD_BOOL cred_handle_initialized = False;
static RD_BOOL have_compat_cred_handle = False;
static SecHandle cred_handle, compat_cred_handle;
static netconn_t g_ssl1;
static netconn_t *g_ssl = NULL;
#endif /* WITH_SSL */
static int g_sock;
static struct stream g_in;
static struct stream g_out[STREAM_COUNT];
int g_tcp_port_rdp = TCP_PORT_RDP;
extern RD_BOOL g_user_quit;
extern RD_BOOL g_network_error;
extern RD_BOOL g_reconnect_loop;

/* Initialise TCP transport data packet */
STREAM
tcp_init(uint32 maxlen)
{
    static int cur_stream_id = 0;
    STREAM result = NULL;

#ifdef WITH_SCARD
    scard_lock(SCARD_LOCK_TCP);
#endif
    result = &g_out[cur_stream_id];
    cur_stream_id = (cur_stream_id + 1) % STREAM_COUNT;

    if (maxlen > result->size)
    {
        result->data = (uint8 *) xrealloc(result->data, maxlen);
        result->size = maxlen;
    }

    result->p = result->data;
    result->end = result->data + result->size;
#ifdef WITH_SCARD
    scard_unlock(SCARD_LOCK_TCP);
#endif
    return result;
}

#ifdef WITH_SSL

RD_BOOL send_ssl_chunk(const void *msg, size_t size)
{
    SecBuffer bufs[4] = {
        {g_ssl->ssl_sizes.cbHeader, SECBUFFER_STREAM_HEADER, g_ssl->ssl_buf},
        {size,  SECBUFFER_DATA, g_ssl->ssl_buf+g_ssl->ssl_sizes.cbHeader},
        {g_ssl->ssl_sizes.cbTrailer, SECBUFFER_STREAM_TRAILER, g_ssl->ssl_buf+g_ssl->ssl_sizes.cbHeader+size},
        {0, SECBUFFER_EMPTY, NULL}
    };
    SecBufferDesc buf_desc = {SECBUFFER_VERSION, sizeof(bufs)/sizeof(*bufs), bufs};
    SECURITY_STATUS res;
    int tcp_res;

    memcpy(bufs[1].pvBuffer, msg, size);
    res = EncryptMessage(&g_ssl->ssl_ctx, 0, &buf_desc, 0);
    if (res != SEC_E_OK)
    {
        error("EncryptMessage failed: %d\n", res);
        return False;
    }

    tcp_res = send(g_sock, g_ssl->ssl_buf, bufs[0].cbBuffer+bufs[1].cbBuffer+bufs[2].cbBuffer, 0);
    if (tcp_res < 1)
    {
        error("send failed: %d (%s)\n", tcp_res, TCP_STRERROR);
        return False;
    }

    return True;
}

DWORD read_ssl_chunk(void *buf, SIZE_T buf_size, BOOL blocking, SIZE_T *ret_size, BOOL *eof)
{
    const SIZE_T ssl_buf_size = g_ssl->ssl_sizes.cbHeader+g_ssl->ssl_sizes.cbMaximumMessage+g_ssl->ssl_sizes.cbTrailer;
    SecBuffer bufs[4];
    SecBufferDesc buf_desc = {SECBUFFER_VERSION, sizeof(bufs)/sizeof(*bufs), bufs};
    SSIZE_T size, buf_len = 0;
    int i;
    SECURITY_STATUS res;

    //assert(conn->extra_len < ssl_buf_size);

    if (g_ssl->extra_len)
    {
        memcpy(g_ssl->ssl_buf, g_ssl->extra_buf, g_ssl->extra_len);
        buf_len = g_ssl->extra_len;
        g_ssl->extra_len = 0;
        xfree(g_ssl->extra_buf);
        g_ssl->extra_buf = NULL;
    }

    size = recv(g_sock, g_ssl->ssl_buf+buf_len, ssl_buf_size-buf_len, 0);
    if (size < 0)
    {
        if (!buf_len)
        {
            if (size == -1 && TCP_BLOCKS)
            {
                return WSAEWOULDBLOCK;
            }
            error("recv failed: %d (%s)\n", size, TCP_STRERROR);
            return -1;//ERROR_INTERNET_CONNECTION_ABORTED;
        }
    }
    else
    {
        buf_len += size;
    }

    if (!buf_len)
    {
        *eof = TRUE;
        *ret_size = 0;
        return ERROR_SUCCESS;
    }

    *eof = FALSE;

    do
    {
        memset(bufs, 0, sizeof(bufs));
        bufs[0].BufferType = SECBUFFER_DATA;
        bufs[0].cbBuffer = buf_len;
        bufs[0].pvBuffer = g_ssl->ssl_buf;

        res = DecryptMessage(&g_ssl->ssl_ctx, &buf_desc, 0, NULL);
        switch (res)
        {
        case SEC_E_OK:
            break;
        case SEC_I_CONTEXT_EXPIRED:
            *eof = TRUE;
            return ERROR_SUCCESS;
        case SEC_E_INCOMPLETE_MESSAGE:
            //assert(buf_len < ssl_buf_size);

            size = recv(g_sock, g_ssl->ssl_buf+buf_len, ssl_buf_size-buf_len, 0);
            if (size < 1)
            {
                if (size == -1 && TCP_BLOCKS)
                {
                    /* FIXME: Optimize extra_buf usage. */
                    g_ssl->extra_buf = xmalloc(buf_len);
                    if (!g_ssl->extra_buf)
                        return ERROR_NOT_ENOUGH_MEMORY;

                    g_ssl->extra_len = buf_len;
                    memcpy(g_ssl->extra_buf, g_ssl->ssl_buf, g_ssl->extra_len);
                    return WSAEWOULDBLOCK;
                }

                error("recv failed: %d (%s)\n", size, TCP_STRERROR);
                return -1;//ERROR_INTERNET_CONNECTION_ABORTED;
            }

            buf_len += size;
            continue;
        default:
            error("DecryptMessage failed: %d\n", res);
            return -1;//ERROR_INTERNET_CONNECTION_ABORTED;
        }
    }
    while (res != SEC_E_OK);

    for (i=0; i < sizeof(bufs)/sizeof(*bufs); i++)
    {
        if (bufs[i].BufferType == SECBUFFER_DATA)
        {
            size = min(buf_size, bufs[i].cbBuffer);
            memcpy(buf, bufs[i].pvBuffer, size);
            if (size < bufs[i].cbBuffer)
            {
                //assert(!conn->peek_len);
                g_ssl->peek_msg_mem = g_ssl->peek_msg = xmalloc(bufs[i].cbBuffer - size);
                if (!g_ssl->peek_msg)
                    return ERROR_NOT_ENOUGH_MEMORY;
                g_ssl->peek_len = bufs[i].cbBuffer-size;
                memcpy(g_ssl->peek_msg, (char*)bufs[i].pvBuffer+size, g_ssl->peek_len);
            }

            *ret_size = size;
        }
    }

    for (i=0; i < sizeof(bufs)/sizeof(*bufs); i++)
    {
        if (bufs[i].BufferType == SECBUFFER_EXTRA)
        {
            g_ssl->extra_buf = xmalloc(bufs[i].cbBuffer);
            if (!g_ssl->extra_buf)
                return ERROR_NOT_ENOUGH_MEMORY;

            g_ssl->extra_len = bufs[i].cbBuffer;
            memcpy(g_ssl->extra_buf, bufs[i].pvBuffer, g_ssl->extra_len);
        }
    }

    return ERROR_SUCCESS;
}
#endif /* WITH_SSL */
/* Send TCP transport data packet */
void
tcp_send(STREAM s)
{
    int length = s->end - s->data;
    int sent, total = 0;

    if (g_network_error == True)
        return;

#ifdef WITH_SCARD
    scard_lock(SCARD_LOCK_TCP);
#endif
    while (total < length)
    {
#ifdef WITH_SSL
        if (g_ssl)
        {
            const BYTE *ptr = s->data + total;
            size_t chunk_size;

            sent = 0;

            while (length - total)
            {
                chunk_size = min(length - total, g_ssl->ssl_sizes.cbMaximumMessage);
                if (!send_ssl_chunk(ptr, chunk_size))
                {
#ifdef WITH_SCARD
                    scard_unlock(SCARD_LOCK_TCP);
#endif

                    //error("send_ssl_chunk: %d (%s)\n", sent, TCP_STRERROR);
                    g_network_error = True;
                    return;
                }

                sent += chunk_size;
                ptr += chunk_size;
                length -= chunk_size;
            }
        }
        else
        {
#endif /* WITH_SSL */
            sent = send(g_sock, (const char *)s->data + total, length - total, 0);
            if (sent <= 0)
            {
                if (sent == -1 && TCP_BLOCKS)
                {
                    TCP_SLEEP(0);
                    sent = 0;
                }
                else
                {
#ifdef WITH_SCARD
                    scard_unlock(SCARD_LOCK_TCP);
#endif

                    error("send: %d (%s)\n", sent, TCP_STRERROR);
                    g_network_error = True;
                    return;
                }
            }
#ifdef WITH_SSL
        }
#endif /* WITH_SSL */
        total += sent;
    }
#ifdef WITH_SCARD
    scard_unlock(SCARD_LOCK_TCP);
#endif
}

/* Receive a message on the TCP layer */
STREAM
tcp_recv(STREAM s, uint32 length)
{
    uint32 new_length, end_offset, p_offset;
    int rcvd = 0;

    if (g_network_error == True)
        return NULL;

    if (s == NULL)
    {
        /* read into "new" stream */
        if (length > g_in.size)
        {
            g_in.data = (uint8 *) xrealloc(g_in.data, length);
            g_in.size = length;
        }
        g_in.end = g_in.p = g_in.data;
        s = &g_in;
    }
    else
    {
        /* append to existing stream */
        new_length = (s->end - s->data) + length;
        if (new_length > s->size)
        {
            p_offset = s->p - s->data;
            end_offset = s->end - s->data;
            s->data = (uint8 *) xrealloc(s->data, new_length);
            s->size = new_length;
            s->p = s->data + p_offset;
            s->end = s->data + end_offset;
        }
    }

    while (length > 0)
    {
#ifdef WITH_SSL
        if (!g_ssl)
#endif /* WITH_SSL */
        {
            if (!ui_select(g_sock))
            {
                /* User quit */
                g_user_quit = True;
                return NULL;
            }
        }

#ifdef WITH_SSL
        if (g_ssl)
        {
            SIZE_T size = 0;
            BOOL eof;
            DWORD res;

            if (g_ssl->peek_msg)
            {
                size = min(length, g_ssl->peek_len);
                memcpy(s->end, g_ssl->peek_msg, size);
                g_ssl->peek_len -= size;
                g_ssl->peek_msg += size;
                s->end += size;

                if (!g_ssl->peek_len)
                {
                    xfree(g_ssl->peek_msg_mem);
                    g_ssl->peek_msg_mem = g_ssl->peek_msg = NULL;
                }

                return s;
            }

            do
            {
                res = read_ssl_chunk((BYTE*)s->end, length, TRUE, &size, &eof);
                if (res != ERROR_SUCCESS)
                {
                    if (res == WSAEWOULDBLOCK)
                    {
                        if (size)
                        {
                            res = ERROR_SUCCESS;
                        }
                    }
                    else
                    {
                        error("read_ssl_chunk: %d (%s)\n", res, TCP_STRERROR);
                        g_network_error = True;
                        return NULL;
                    }
                    break;
                }
            }
            while (!size && !eof);
            rcvd = size;
        }
        else
        {
#endif /* WITH_SSL */
            rcvd = recv(g_sock, (char *)s->end, length, 0);
            if (rcvd < 0)
            {
                if (rcvd == -1 && TCP_BLOCKS)
                {
                    rcvd = 0;
                }
                else
                {
                    error("recv: %d (%s)\n", rcvd, TCP_STRERROR);
                    g_network_error = True;
                    return NULL;
                }
            }
            else if (rcvd == 0)
            {
                error("Connection closed\n");
                return NULL;
            }
#ifdef WITH_SSL
        }
#endif /* WITH_SSL */

        s->end += rcvd;
        length -= rcvd;
    }

    return s;
}

#ifdef WITH_SSL

RD_BOOL
ensure_cred_handle(void)
{
    SECURITY_STATUS res = SEC_E_OK;

    if (!cred_handle_initialized)
    {
        SCHANNEL_CRED cred = {SCHANNEL_CRED_VERSION};
        SecPkgCred_SupportedProtocols prots;

        res = AcquireCredentialsHandleW(NULL, (WCHAR*)UNISP_NAME_W, SECPKG_CRED_OUTBOUND, NULL, &cred,
                NULL, NULL, &cred_handle, NULL);
        if (res == SEC_E_OK)
        {
            res = QueryCredentialsAttributesA(&cred_handle, SECPKG_ATTR_SUPPORTED_PROTOCOLS, &prots);
            if (res != SEC_E_OK || (prots.grbitProtocol & SP_PROT_TLS1_1PLUS_CLIENT))
            {
                cred.grbitEnabledProtocols = prots.grbitProtocol & ~SP_PROT_TLS1_1PLUS_CLIENT;
                res = AcquireCredentialsHandleW(NULL, (WCHAR*)UNISP_NAME_W, SECPKG_CRED_OUTBOUND, NULL, &cred,
                        NULL, NULL, &compat_cred_handle, NULL);
                have_compat_cred_handle = res == SEC_E_OK;
            }
        }

        cred_handle_initialized = res == SEC_E_OK;
    }

    if (res != SEC_E_OK)
    {
        error("ensure_cred_handle failed: %ld\n", res);
        return False;
    }

    return True;
}

DWORD
ssl_handshake(RD_BOOL compat_mode)
{
    SecBuffer out_buf = {0, SECBUFFER_TOKEN, NULL}, in_bufs[2] = {{0, SECBUFFER_TOKEN}, {0, SECBUFFER_EMPTY}};
    SecBufferDesc out_desc = {SECBUFFER_VERSION, 1, &out_buf}, in_desc = {SECBUFFER_VERSION, 2, in_bufs};
    SecHandle *cred = &cred_handle;
    BYTE *read_buf;
    SIZE_T read_buf_size = 2048;
    ULONG attrs = 0;
    CtxtHandle ctx;
    SSIZE_T size;
    SECURITY_STATUS status;
    DWORD res = ERROR_SUCCESS;

    const DWORD isc_req_flags = ISC_REQ_ALLOCATE_MEMORY|ISC_REQ_USE_SESSION_KEY|ISC_REQ_CONFIDENTIALITY
        |ISC_REQ_SEQUENCE_DETECT|ISC_REQ_REPLAY_DETECT|ISC_REQ_MANUAL_CRED_VALIDATION;

    if (!ensure_cred_handle())
        return -1;

    if (compat_mode) {
        if (!have_compat_cred_handle)
            return -1;
        cred = &compat_cred_handle;
    }

    read_buf = xmalloc(read_buf_size);
    if (!read_buf)
        return ERROR_OUTOFMEMORY;

    if (!g_ssl_server)
        return -1;

    status = InitializeSecurityContextA(cred, NULL, g_ssl_server, isc_req_flags, 0, 0, NULL, 0,
            &ctx, &out_desc, &attrs, NULL);

    //assert(status != SEC_E_OK);

    while (status == SEC_I_CONTINUE_NEEDED || status == SEC_E_INCOMPLETE_MESSAGE)
    {
        if (out_buf.cbBuffer)
        {
            //assert(status == SEC_I_CONTINUE_NEEDED);

            size = send(g_sock, out_buf.pvBuffer, out_buf.cbBuffer, 0);
            if (size != out_buf.cbBuffer)
            {
                error("send failed: %d (%s)\n", size, TCP_STRERROR);
                status = -1;
                break;
            }

            FreeContextBuffer(out_buf.pvBuffer);
            out_buf.pvBuffer = NULL;
            out_buf.cbBuffer = 0;
        }

        if (status == SEC_I_CONTINUE_NEEDED)
        {
            //assert(in_bufs[1].cbBuffer < read_buf_size);

            memmove(read_buf, (BYTE*)in_bufs[0].pvBuffer+in_bufs[0].cbBuffer-in_bufs[1].cbBuffer, in_bufs[1].cbBuffer);
            in_bufs[0].cbBuffer = in_bufs[1].cbBuffer;

            in_bufs[1].BufferType = SECBUFFER_EMPTY;
            in_bufs[1].cbBuffer = 0;
            in_bufs[1].pvBuffer = NULL;
        }

        //assert(in_bufs[0].BufferType == SECBUFFER_TOKEN);
        //assert(in_bufs[1].BufferType == SECBUFFER_EMPTY);

        if (in_bufs[0].cbBuffer + 1024 > read_buf_size)
        {
            BYTE *new_read_buf = xrealloc(read_buf, read_buf_size + 1024);
            if (!new_read_buf)
            {
                status = E_OUTOFMEMORY;
                break;
            }

            in_bufs[0].pvBuffer = read_buf = new_read_buf;
            read_buf_size += 1024;
        }

        size = recv(g_sock, (char *)read_buf + in_bufs[0].cbBuffer, read_buf_size - in_bufs[0].cbBuffer, 0);
        if (size < 1)
        {
            error("recv failed: %d (%s)\n", size, TCP_STRERROR);
            res = -1;
            break;
        }

        in_bufs[0].cbBuffer += size;
        in_bufs[0].pvBuffer = read_buf;
        status = InitializeSecurityContextA(cred, &ctx, g_ssl_server,  isc_req_flags, 0, 0, &in_desc,
                0, NULL, &out_desc, &attrs, NULL);

        if (status == SEC_E_OK) {
            if (SecIsValidHandle(&g_ssl->ssl_ctx))
                DeleteSecurityContext(&g_ssl->ssl_ctx);
            g_ssl->ssl_ctx = ctx;

            if (in_bufs[1].BufferType == SECBUFFER_EXTRA)
            {
                //FIXME("SECBUFFER_EXTRA not supported\n");
            }

            status = QueryContextAttributesW(&ctx, SECPKG_ATTR_STREAM_SIZES, &g_ssl->ssl_sizes);
            if (status != SEC_E_OK)
            {
                //error("Can't determine ssl buffer sizes: %ld\n", status);
                break;
            }

            g_ssl->ssl_buf = xmalloc(g_ssl->ssl_sizes.cbHeader + g_ssl->ssl_sizes.cbMaximumMessage
                    + g_ssl->ssl_sizes.cbTrailer);
            if (!g_ssl->ssl_buf)
            {
                res = GetLastError();
                break;
            }
        }
    }

    xfree(read_buf);

    if (status != SEC_E_OK || res != ERROR_SUCCESS)
    {
        error("Failed to establish SSL connection: %08x (%u)\n", status, res);
        xfree(g_ssl->ssl_buf);
        g_ssl->ssl_buf = NULL;
        return res ? res : -1;
    }

    return ERROR_SUCCESS;
}

/* Establish a SSL/TLS 1.0 connection */
RD_BOOL
tcp_tls_connect(void)
{
    int err;
    char tcp_port_rdp_s[10];

    if (!g_ssl_initialized)
    {
        g_ssl = &g_ssl1;
        SecInvalidateHandle(&g_ssl->ssl_ctx);

        g_ssl_initialized = True;
    }

    snprintf(tcp_port_rdp_s, 10, "%d", g_tcp_port_rdp);
    if ((err = ssl_handshake(FALSE)) != 0)
    {
        goto fail;
    }

    return True;

      fail:
    g_ssl = NULL;
    return False;
}

/* Get public key from server of TLS 1.0 connection */
RD_BOOL
tcp_tls_get_server_pubkey(STREAM s)
{
    const CERT_CONTEXT *cert = NULL;
    SECURITY_STATUS status;

    s->data = s->p = NULL;
    s->size = 0;

    if (g_ssl == NULL)
        goto out;
    status = QueryContextAttributesW(&g_ssl->ssl_ctx, SECPKG_ATTR_REMOTE_CERT_CONTEXT, (void*)&cert);
    if (status != SEC_E_OK)
    {
        error("tcp_tls_get_server_pubkey: QueryContextAttributesW() failed %ld\n", status);
        goto out;
    }

    s->size = cert->cbCertEncoded;
    if (s->size < 1)
    {
        error("tcp_tls_get_server_pubkey: cert->cbCertEncoded = %ld\n", cert->cbCertEncoded);
        goto out;
    }

    s->data = s->p = (unsigned char *)xmalloc(s->size);
    memcpy(cert->pbCertEncoded, &s->p, s->size);
    s->p = s->data;
    s->end = s->p + s->size;

      out:
    if (cert)
        CertFreeCertificateContext(cert);
    return (s->size != 0);
}
#endif /* WITH_SSL */

/* Establish a connection on the TCP layer */
RD_BOOL
tcp_connect(char *server)
{
    socklen_t option_len;
    uint32 option_value;
    int i;

#ifdef IPv6

    int n;
    struct addrinfo hints, *res, *ressave;
    char tcp_port_rdp_s[10];

    snprintf(tcp_port_rdp_s, 10, "%d", g_tcp_port_rdp);

    memset(&hints, 0, sizeof(struct addrinfo));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;

    if ((n = getaddrinfo(server, tcp_port_rdp_s, &hints, &res)))
    {
        error("getaddrinfo: %s\n", gai_strerror(n));
        return False;
    }

    ressave = res;
    g_sock = -1;
    while (res)
    {
        g_sock = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
        if (!(g_sock < 0))
        {
            if (connect(g_sock, res->ai_addr, res->ai_addrlen) == 0)
                break;
            TCP_CLOSE(g_sock);
            g_sock = -1;
        }
        res = res->ai_next;
    }
    freeaddrinfo(ressave);

    if (g_sock == -1)
    {
        error("%s: unable to connect\n", server);
        return False;
    }

#else /* no IPv6 support */

    struct hostent *nslookup;
    struct sockaddr_in servaddr;

    if ((nslookup = gethostbyname(server)) != NULL)
    {
        memcpy(&servaddr.sin_addr, nslookup->h_addr, sizeof(servaddr.sin_addr));
    }
    else if ((servaddr.sin_addr.s_addr = inet_addr(server)) == INADDR_NONE)
    {
        error("%s: unable to resolve host\n", server);
        return False;
    }

    if ((g_sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        error("socket: %s\n", TCP_STRERROR);
        return False;
    }

    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons((uint16) g_tcp_port_rdp);

    if (connect(g_sock, (struct sockaddr *) &servaddr, sizeof(struct sockaddr)) < 0)
    {
        if (!g_reconnect_loop)
            error("connect: %s\n", TCP_STRERROR);

        TCP_CLOSE(g_sock);
        g_sock = -1;
        return False;
    }

#endif /* IPv6 */

    option_value = 1;
    option_len = sizeof(option_value);
    setsockopt(g_sock, IPPROTO_TCP, TCP_NODELAY, (void *) &option_value, option_len);
    /* receive buffer must be a least 16 K */
    if (getsockopt(g_sock, SOL_SOCKET, SO_RCVBUF, (void *) &option_value, &option_len) == 0)
    {
        if (option_value < (1024 * 16))
        {
            option_value = 1024 * 16;
            option_len = sizeof(option_value);
            setsockopt(g_sock, SOL_SOCKET, SO_RCVBUF, (void *) &option_value,
                   option_len);
        }
    }

    g_in.size = 4096;
    g_in.data = (uint8 *) xmalloc(g_in.size);

    for (i = 0; i < STREAM_COUNT; i++)
    {
        g_out[i].size = 4096;
        g_out[i].data = (uint8 *) xmalloc(g_out[i].size);
    }

#ifdef WITH_SSL
    g_ssl_server = xmalloc(strlen(server)+1);
#endif /* WITH_SSL */

    return True;
}

/* Disconnect on the TCP layer */
void
tcp_disconnect(void)
{
#ifdef WITH_SSL
    if (g_ssl)
    {
        xfree(g_ssl->peek_msg_mem);
        g_ssl->peek_msg_mem = NULL;
        g_ssl->peek_msg = NULL;
        g_ssl->peek_len = 0;
        xfree(g_ssl->ssl_buf);
        g_ssl->ssl_buf = NULL;
        xfree(g_ssl->extra_buf);
        g_ssl->extra_buf = NULL;
        g_ssl->extra_len = 0;
        if (SecIsValidHandle(&g_ssl->ssl_ctx))
            DeleteSecurityContext(&g_ssl->ssl_ctx);
        if (cred_handle_initialized)
            FreeCredentialsHandle(&cred_handle);
        if (have_compat_cred_handle)
            FreeCredentialsHandle(&compat_cred_handle);
        if (g_ssl_server)
        {
            xfree(g_ssl_server);
            g_ssl_server = NULL;
        }
        g_ssl = NULL;
        g_ssl_initialized = False;
    }
#endif /* WITH_SSL */
    TCP_CLOSE(g_sock);
    g_sock = -1;
}

char *
tcp_get_address()
{
    static char ipaddr[32];
    struct sockaddr_in sockaddr;
    socklen_t len = sizeof(sockaddr);
    if (getsockname(g_sock, (struct sockaddr *) &sockaddr, &len) == 0)
    {
        uint8 *ip = (uint8 *) & sockaddr.sin_addr;
        sprintf(ipaddr, "%d.%d.%d.%d", ip[0], ip[1], ip[2], ip[3]);
    }
    else
        strcpy(ipaddr, "127.0.0.1");
    return ipaddr;
}

RD_BOOL
tcp_is_connected()
{
    struct sockaddr_in sockaddr;
    socklen_t len = sizeof(sockaddr);
    if (getpeername(g_sock, (struct sockaddr *) &sockaddr, &len))
        return True;
    return False;
}

/* reset the state of the tcp layer */
/* Support for Session Directory */
void
tcp_reset_state(void)
{
    int i;

    /* Clear the incoming stream */
    if (g_in.data != NULL)
        xfree(g_in.data);
    g_in.p = NULL;
    g_in.end = NULL;
    g_in.data = NULL;
    g_in.size = 0;
    g_in.iso_hdr = NULL;
    g_in.mcs_hdr = NULL;
    g_in.sec_hdr = NULL;
    g_in.rdp_hdr = NULL;
    g_in.channel_hdr = NULL;

    /* Clear the outgoing stream(s) */
    for (i = 0; i < STREAM_COUNT; i++)
    {
        if (g_out[i].data != NULL)
            xfree(g_out[i].data);
        g_out[i].p = NULL;
        g_out[i].end = NULL;
        g_out[i].data = NULL;
        g_out[i].size = 0;
        g_out[i].iso_hdr = NULL;
        g_out[i].mcs_hdr = NULL;
        g_out[i].sec_hdr = NULL;
        g_out[i].rdp_hdr = NULL;
        g_out[i].channel_hdr = NULL;
    }
}