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sockets.c

/*
 * sockets.c - deal with TCP sockets.
 *
 * This code should be independent of any changes in the RFB protocol.  It just
 * deals with the X server scheduling stuff, calling rfbNewClientConnection and
 * rfbProcessClientMessage to actually deal with the protocol.  If a socket
 * needs to be closed for any reason then rfbCloseClient should be called, and
 * this in turn will call rfbClientConnectionGone.  To make an active
 * connection out, call rfbConnect - note that this does _not_ call
 * rfbNewClientConnection.
 *
 * This file is divided into two types of function.  Those beginning with
 * "rfb" are specific to sockets using the RFB protocol.  Those without the
 * "rfb" prefix are more general socket routines (which are used by the http
 * code).
 *
 * Thanks to Karl Hakimian for pointing out that some platforms return EAGAIN
 * not EWOULDBLOCK.
 */

/*
 *  OSXvnc Copyright (C) 2001 Dan McGuirk <mcguirk@incompleteness.net>.
 *  Original Xvnc code Copyright (C) 1999 AT&T Laboratories Cambridge.  
 *  All Rights Reserved.
 *
 *  This 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 software 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 software; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
 *  USA.
 */

#include <rfb/rfb.h>

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#ifdef WIN32
#pragma warning (disable: 4018 4761)
#define close closesocket
#define read(sock,buf,len) recv(sock,buf,len,0)
#define EWOULDBLOCK WSAEWOULDBLOCK
#define ETIMEDOUT WSAETIMEDOUT
#define write(sock,buf,len) send(sock,buf,len,0)
#else
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>
#include <arpa/inet.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#endif

#if defined(__linux__) && defined(NEED_TIMEVAL)
struct timeval 
{
   long int tv_sec,tv_usec;
}
;
#endif

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif

#include <errno.h>

#ifdef USE_LIBWRAP
#include <syslog.h>
#include <tcpd.h>
int allow_severity=LOG_INFO;
int deny_severity=LOG_WARNING;
#endif

/*#ifndef WIN32
int max(int i,int j) { return(i<j?j:i); }
#endif
*/

int rfbMaxClientWait = 20000;   /* time (ms) after which we decide client has
                                   gone away - needed to stop us hanging */

/*
 * rfbInitSockets sets up the TCP sockets to listen for RFB
 * connections.  It does nothing if called again.
 */

void
rfbInitSockets(rfbScreenInfoPtr rfbScreen)
{
    if (rfbScreen->socketInitDone)
      return;

    rfbScreen->socketInitDone = TRUE;

    if (rfbScreen->inetdSock != -1) {
      const int one = 1;

#ifndef WIN32
      if (fcntl(rfbScreen->inetdSock, F_SETFL, O_NONBLOCK) < 0) {
          rfbLogPerror("fcntl");
          return;
      }
#endif

      if (setsockopt(rfbScreen->inetdSock, IPPROTO_TCP, TCP_NODELAY,
                   (char *)&one, sizeof(one)) < 0) {
          rfbLogPerror("setsockopt");
          return;
      }

      FD_ZERO(&(rfbScreen->allFds));
      FD_SET(rfbScreen->inetdSock, &(rfbScreen->allFds));
      rfbScreen->maxFd = rfbScreen->inetdSock;
      return;
    }

    if(rfbScreen->autoPort) {
        int i;
        rfbLog("Autoprobing TCP port \n");

        for (i = 5900; i < 6000; i++) {
            if ((rfbScreen->rfbListenSock = ListenOnTCPPort(i)) >= 0) {
            rfbScreen->rfbPort = i;
            break;
          }
        }

        if (i >= 6000) {
          rfbLogPerror("Failure autoprobing");
          return;
        }

        rfbLog("Autoprobing selected port %d\n", rfbScreen->rfbPort);
        FD_ZERO(&(rfbScreen->allFds));
        FD_SET(rfbScreen->rfbListenSock, &(rfbScreen->allFds));
        rfbScreen->maxFd = rfbScreen->rfbListenSock;
    }
    else if(rfbScreen->rfbPort>0) {
      rfbLog("Listening for VNC connections on TCP port %d\n", rfbScreen->rfbPort);

      if ((rfbScreen->rfbListenSock = ListenOnTCPPort(rfbScreen->rfbPort)) < 0) {
      rfbLogPerror("ListenOnTCPPort");
      return;
      }

      FD_ZERO(&(rfbScreen->allFds));
      FD_SET(rfbScreen->rfbListenSock, &(rfbScreen->allFds));
      rfbScreen->maxFd = rfbScreen->rfbListenSock;
    }
}

void
rfbProcessNewConnection(rfbScreenInfoPtr rfbScreen)
{
    struct sockaddr_in addr;
    size_t addrlen = sizeof(addr);
    const int one = 1;
    int sock;

    if ((sock = accept(rfbScreen->rfbListenSock,
                   (struct sockaddr *)&addr, &addrlen)) < 0) {
      rfbLogPerror("rfbCheckFds: accept");
      return;
    }

#ifndef WIN32
    if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0) {
      rfbLogPerror("rfbCheckFds: fcntl");
      close(sock);
      return;
    }
#endif

    if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY,
               (char *)&one, sizeof(one)) < 0) {
      rfbLogPerror("rfbCheckFds: setsockopt");
      close(sock);
      return;
    }

#ifdef USE_LIBWRAP
    if(!hosts_ctl("vnc",STRING_UNKNOWN,inet_ntoa(addr.sin_addr),
              STRING_UNKNOWN)) {
      rfbLog("Rejected connection from client %s\n",
             inet_ntoa(addr.sin_addr));
      close(sock);
      return;
    }
#endif

    rfbLog("Got connection from client %s\n", inet_ntoa(addr.sin_addr));

    rfbNewClient(rfbScreen,sock);
}

/*
 * rfbCheckFds is called from ProcessInputEvents to check for input on the RFB
 * socket(s).  If there is input to process, the appropriate function in the
 * RFB server code will be called (rfbNewClientConnection,
 * rfbProcessClientMessage, etc).
 */

void
rfbCheckFds(rfbScreenInfoPtr rfbScreen,long usec)
{
    int nfds;
    fd_set fds;
    struct timeval tv;
    rfbClientIteratorPtr i;
    rfbClientPtr cl;

    if (!rfbScreen->inetdInitDone && rfbScreen->inetdSock != -1) {
      rfbNewClientConnection(rfbScreen,rfbScreen->inetdSock); 
      rfbScreen->inetdInitDone = TRUE;
    }

    memcpy((char *)&fds, (char *)&(rfbScreen->allFds), sizeof(fd_set));
    tv.tv_sec = 0;
    tv.tv_usec = usec;
    nfds = select(rfbScreen->maxFd + 1, &fds, NULL, NULL /* &fds */, &tv);
    if (nfds == 0) {
      return;
    }
    if (nfds < 0) {
#ifdef WIN32
            errno = WSAGetLastError();
#endif
      if (errno != EINTR)
            rfbLogPerror("rfbCheckFds: select");
      return;
    }

    if (rfbScreen->rfbListenSock != -1 && FD_ISSET(rfbScreen->rfbListenSock, &fds)) {
      rfbProcessNewConnection(rfbScreen);
      FD_CLR(rfbScreen->rfbListenSock, &fds);
      if (--nfds == 0)
          return;
    }

    i = rfbGetClientIterator(rfbScreen);
    while((cl = rfbClientIteratorNext(i))) {
      if (cl->onHold)
      continue;
      if (FD_ISSET(cl->sock, &fds) && FD_ISSET(cl->sock, &(rfbScreen->allFds)))
      rfbProcessClientMessage(cl);
    }
    rfbReleaseClientIterator(i);
}

void
rfbCloseClient(cl)
     rfbClientPtr cl;
{
    rfbAuthCleanupClient(cl);

    LOCK(cl->updateMutex);
#ifdef LIBVNCSERVER_HAVE_LIBPTHREAD
    if (cl->sock != -1)
#endif
      {
      FD_CLR(cl->sock,&(cl->screen->allFds));
      if(cl->sock==cl->screen->maxFd)
        while(cl->screen->maxFd>0
            && !FD_ISSET(cl->screen->maxFd,&(cl->screen->allFds)))
          cl->screen->maxFd--;
      shutdown(cl->sock,SHUT_RDWR);
      close(cl->sock);
      cl->sock = -1;
      }
    TSIGNAL(cl->updateCond);
    UNLOCK(cl->updateMutex);
}


/*
 * rfbConnect is called to make a connection out to a given TCP address.
 */

int
rfbConnect(rfbScreen, host, port)
    rfbScreenInfoPtr rfbScreen;
    char *host;
    int port;
{
    int sock;
    int one = 1;

    rfbLog("Making connection to client on host %s port %d\n",
         host,port);

    if ((sock = ConnectToTcpAddr(host, port)) < 0) {
      rfbLogPerror("connection failed");
      return -1;
    }

#ifndef WIN32
    if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0) {
      rfbLogPerror("fcntl failed");
      close(sock);
      return -1;
    }
#endif

    if (setsockopt(sock, IPPROTO_TCP, TCP_NODELAY,
               (char *)&one, sizeof(one)) < 0) {
      rfbLogPerror("setsockopt failed");
      close(sock);
      return -1;
    }

    /* AddEnabledDevice(sock); */
    FD_SET(sock, &rfbScreen->allFds);
    rfbScreen->maxFd = max(sock,rfbScreen->maxFd);

    return sock;
}

#ifdef HAVE_GNUTLS
static int
ReadExactOverTLS(rfbClientPtr cl, char* buf, int len, int timeout)
{
    while (len > 0) {
      int n;

      n = gnutls_record_recv(cl->tlsSession, buf, len);
      if (n == 0) {
          UNLOCK(cl->outputMutex);
          return 0;

      } else if (n < 0) {
          if (n == GNUTLS_E_INTERRUPTED || n == GNUTLS_E_AGAIN)
            continue;

          UNLOCK(cl->outputMutex);
          return -1;
      }

      buf += n;
      len -= n;
    }

    return 1;
}
#endif /* HAVE_GNUTLS */

/*
 * ReadExact reads an exact number of bytes from a client.  Returns 1 if
 * those bytes have been read, 0 if the other end has closed, or -1 if an error
 * occurred (errno is set to ETIMEDOUT if it timed out).
 */

int
ReadExactTimeout(rfbClientPtr cl, char* buf, int len, int timeout)
{
    int sock = cl->sock;
    int n;
    fd_set fds;
    struct timeval tv;

#ifdef HAVE_GNUTLS
    if (cl->useTLS)
      return ReadExactOverTLS(cl, buf, len, timeout);
#endif

    while (len > 0) {
        n = read(sock, buf, len);

        if (n > 0) {

            buf += n;
            len -= n;

        } else if (n == 0) {

            return 0;

        } else {
#ifdef WIN32
                  errno = WSAGetLastError();
#endif
          if (errno == EINTR)
            continue;

            if (errno != EWOULDBLOCK && errno != EAGAIN) {
                return n;
            }

            FD_ZERO(&fds);
            FD_SET(sock, &fds);
            tv.tv_sec = timeout / 1000;
            tv.tv_usec = (timeout % 1000) * 1000;
            n = select(sock+1, &fds, NULL, &fds, &tv);
            if (n < 0) {
                rfbLogPerror("ReadExact: select");
                return n;
            }
            if (n == 0) {
                errno = ETIMEDOUT;
                return -1;
            }
        }
    }
    return 1;
}

int ReadExact(rfbClientPtr cl,char* buf,int len)
{
  return(ReadExactTimeout(cl,buf,len,rfbMaxClientWait));
}

#ifdef HAVE_GNUTLS
static int
WriteExactOverTLS(rfbClientPtr cl, const char* buf, int len)
{
    LOCK(cl->outputMutex);

    while (len > 0) {
      int n;

      n = gnutls_record_send(cl->tlsSession, buf, len);
      if (n == 0) {
          UNLOCK(cl->outputMutex);
          return 0;

      } else if (n < 0) {
          if (n == GNUTLS_E_INTERRUPTED || n == GNUTLS_E_AGAIN)
            continue;

          UNLOCK(cl->outputMutex);
          return -1;
      }

      buf += n;
      len -= n;
    }

    UNLOCK(cl->outputMutex);

    return 1;
}
#endif /* HAVE_GNUTLS */

/*
 * WriteExact writes an exact number of bytes to a client.  Returns 1 if
 * those bytes have been written, or -1 if an error occurred (errno is set to
 * ETIMEDOUT if it timed out).
 */

int
WriteExact(rfbClientPtr cl, const char* buf, int len)
{
    int sock = cl->sock;
    int n;
    fd_set fds;
    struct timeval tv;
    int totalTimeWaited = 0;

#ifdef HAVE_GNUTLS
    if (cl->useTLS)
      return WriteExactOverTLS(cl, buf, len);
#endif

    LOCK(cl->outputMutex);
    while (len > 0) {
        n = write(sock, buf, len);

        if (n > 0) {

            buf += n;
            len -= n;

        } else if (n == 0) {

            rfbErr("WriteExact: write returned 0?\n");
            return 0;

        } else {
#ifdef WIN32
                  errno = WSAGetLastError();
#endif
          if (errno == EINTR)
            continue;

            if (errno != EWOULDBLOCK && errno != EAGAIN) {
              UNLOCK(cl->outputMutex);
                return n;
            }

            /* Retry every 5 seconds until we exceed rfbMaxClientWait.  We
               need to do this because select doesn't necessarily return
               immediately when the other end has gone away */

            FD_ZERO(&fds);
            FD_SET(sock, &fds);
            tv.tv_sec = 5;
            tv.tv_usec = 0;
            n = select(sock+1, NULL, &fds, NULL /* &fds */, &tv);
            if (n < 0) {
                rfbLogPerror("WriteExact: select");
                UNLOCK(cl->outputMutex);
                return n;
            }
            if (n == 0) {
                totalTimeWaited += 5000;
                if (totalTimeWaited >= rfbMaxClientWait) {
                    errno = ETIMEDOUT;
                    UNLOCK(cl->outputMutex);
                    return -1;
                }
            } else {
                totalTimeWaited = 0;
            }
        }
    }
    UNLOCK(cl->outputMutex);
    return 1;
}

int
ListenOnTCPPort(port)
    int port;
{
    struct sockaddr_in addr;
    int sock;
    int one = 1;

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    /* addr.sin_addr.s_addr = interface.s_addr; */
    addr.sin_addr.s_addr = INADDR_ANY;

    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
      return -1;
    }
    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
               (char *)&one, sizeof(one)) < 0) {
      close(sock);
      return -1;
    }
    if (bind(sock, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
      close(sock);
      return -1;
    }
    if (listen(sock, 5) < 0) {
      close(sock);
      return -1;
    }

    return sock;
}

int
ConnectToTcpAddr(host, port)
    char *host;
    int port;
{
    struct hostent *hp;
    int sock;
    struct sockaddr_in addr;

    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);

    if ((addr.sin_addr.s_addr = inet_addr(host)) == INADDR_NONE)
    {
      if (!(hp = gethostbyname(host))) {
          errno = EINVAL;
          return -1;
      }
      addr.sin_addr.s_addr = *(unsigned long *)hp->h_addr;
    }

    if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
      return -1;
    }

    if (connect(sock, (struct sockaddr *)&addr, (sizeof(addr))) < 0) {
      close(sock);
      return -1;
    }

    return sock;
}

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