tcp.c

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/* -*- c-basic-offset: 8 -*-
   rdesktop: A Remote Desktop Protocol client.
   Protocol services - TCP layer
   Copyright (C) Matthew Chapman 1999-2005

   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 2 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, write to the Free Software Foundation, Inc.,
   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/


#include <precomp.h>

#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

static int sock;
static struct stream in;
static struct stream out;
int g_tcp_port_rdp = TCP_PORT_RDP;

/* Initialise TCP transport data packet */
STREAM
tcp_init(uint32 maxlen)
{
    if (maxlen > out.size)
    {
        out.data = (uint8 *) xrealloc(out.data, maxlen);
        out.size = maxlen;
    }

    out.p = out.data;
    out.end = out.data + out.size;
    return &out;
}

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

    while (total < length)
    {
        sent = send(sock, (char *)s->data + total, length - total, 0);
        if (sent <= 0)
        {
            if (sent == -1 && TCP_BLOCKS)
            {
                TCP_SLEEP(0);
                sent = 0;
            }
            else
            {
                error("send: %s\n", TCP_STRERROR);
                return;
            }
        }
        total += sent;
    }
}

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

    if (s == NULL)
    {
        /* read into "new" stream */
        if (length > in.size)
        {
            in.data = (uint8 *) xrealloc(in.data, length);
            in.size = length;
        }
        in.end = in.p = in.data;
        s = &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)
    {
        if (!ui_select(sock))
            /* User quit */
            return NULL;

        rcvd = recv(sock, (char *)s->end, length, 0);
        if (rcvd < 0)
        {
            if (rcvd == -1 && TCP_BLOCKS)
            {
                TCP_SLEEP(0);
                rcvd = 0;
            }
            else
            {
                error("recv: %s\n", TCP_STRERROR);
                return NULL;
            }
        }
        else if (rcvd == 0)
        {
            error("Connection closed\n");
            return NULL;
        }

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

    return s;
}

/* Establish a connection on the TCP layer */
BOOL
tcp_connect(char *server)
{
    int true_value = 1;

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

    if (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 ((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(sock, (struct sockaddr *) &servaddr, sizeof(struct sockaddr)) < 0)
    {
        error("connect: %s\n", TCP_STRERROR);
        TCP_CLOSE(sock);
        return False;
    }

#endif /* IPv6 */

    setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void *) &true_value, sizeof(true_value));

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

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

    return True;
}

/* Disconnect on the TCP layer */
void
tcp_disconnect(void)
{
    TCP_CLOSE(sock);
}

char *
tcp_get_address()
{
    static char ipaddr[32];
    struct sockaddr_in sockaddr;
    socklen_t len = sizeof(sockaddr);
    if (getsockname(sock, (struct sockaddr *) &sockaddr, &len) == 0)
    {
        unsigned char *ip = (unsigned char *) &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;
}

/* reset the state of the tcp layer */
/* Support for Session Directory */
void
tcp_reset_state(void)
{
    sock = -1;      /* reset socket */

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

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