path: root/xdmcp.c

/* $Xorg: xdmcp.c,v 1.4 2001/02/09 02:05:41 xorgcvs Exp $ */
/*

Copyright 1988, 1998  The Open Group

Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of The Open Group shall
not be used in advertising or otherwise to promote the sale, use or
other dealings in this Software without prior written authorization
from The Open Group.

*/

/*
 * xdm - display manager daemon
 * Author:  Keith Packard, MIT X Consortium
 *
 * xdmcp.c - Support for XDMCP
 */

# include "dm.h"

#ifdef XDMCP

# include	<X11/X.h>
# include	<X11/Xfuncs.h>
# include	<sys/types.h>
# include	<ctype.h>

#include	<sys/socket.h>
#include	<netinet/in.h>
#include	<sys/un.h>
#include	<netdb.h>

#ifdef X_NOT_STDC_ENV
#define Time_t long
extern Time_t time ();
#else
#include <time.h>
#define Time_t time_t
#endif

#define getString(name,len)	((name = malloc (len + 1)) ? 1 : 0)

/*
 * interface to policy routines
 */

extern ARRAY8Ptr	ChooseAuthentication ();
extern int		Willing ();
extern ARRAY8Ptr	Accept ();
extern int		SelectConnectionTypeIndex ();

int	xdmcpFd = -1;
int	chooserFd = -1;

FD_TYPE	WellKnownSocketsMask;
int	WellKnownSocketsMax;

#define pS(s)	((s) ? ((char *) (s)) : "empty string")

DestroyWellKnownSockets ()
{
    if (xdmcpFd != -1)
    {
	close (xdmcpFd);
	xdmcpFd = -1;
    }
    if (chooserFd != -1)
    {
	close (chooserFd);
	chooserFd = -1;
    }
}

AnyWellKnownSockets ()
{
    return xdmcpFd != -1 || chooserFd != -1;
}

static XdmcpBuffer	buffer;

/*ARGSUSED*/
static void
sendForward (connectionType, address, closure)
    CARD16	connectionType;
    ARRAY8Ptr	address;
    char	*closure;
{
#ifdef AF_INET
    struct sockaddr_in	    in_addr;
#endif
#ifdef AF_DECnet
#endif
    struct sockaddr	    *addr;
    int			    addrlen;

    switch (connectionType)
    {
#ifdef AF_INET
    case FamilyInternet:
	addr = (struct sockaddr *) &in_addr;
	bzero ((char *) &in_addr, sizeof (in_addr));
#ifdef BSD44SOCKETS
	in_addr.sin_len = sizeof(in_addr);
#endif
	in_addr.sin_family = AF_INET;
	in_addr.sin_port = htons ((short) XDM_UDP_PORT);
	if (address->length != 4)
	    return;
	memmove( (char *) &in_addr.sin_addr, address->data, address->length);
	addrlen = sizeof (struct sockaddr_in);
	break;
#endif
#ifdef AF_DECnet
    case FamilyDECnet:
#endif
    default:
	return;
    }
    XdmcpFlush (xdmcpFd, &buffer, addr, addrlen);
}

extern char *NetaddrAddress();
extern char *NetaddrPort();

static void
ClientAddress (from, addr, port, type)
    struct sockaddr *from;
    ARRAY8Ptr	    addr, port;	/* return */
    CARD16	    *type;	/* return */
{
    int length, family;
    char *data;

    data = NetaddrPort(from, &length);
    XdmcpAllocARRAY8 (port, length);
    memmove( port->data, data, length);
    port->length = length;

    family = ConvertAddr(from, &length, &data);
    XdmcpAllocARRAY8 (addr, length);
    memmove( addr->data, data, length);
    addr->length = length;

    *type = family;
}

static void
all_query_respond (from, fromlen, authenticationNames, type)
    struct sockaddr	*from;
    int			fromlen;
    ARRAYofARRAY8Ptr	authenticationNames;
    xdmOpCode		type;
{
    ARRAY8Ptr	authenticationName;
    ARRAY8	status;
    ARRAY8	addr;
    CARD16	connectionType;
    int		family;
    int		length;

    family = ConvertAddr(from, &length, &(addr.data));
    addr.length = length;	/* convert int to short */
    Debug ("all_query_respond: conntype=%d, addr=%lx, len=%d\n",
	   family, *(addr.data), addr.length);
    if (family < 0)
	return;
    connectionType = family;

    if (type == INDIRECT_QUERY)
	RememberIndirectClient (&addr, connectionType);
    else
	ForgetIndirectClient (&addr, connectionType);

    authenticationName = ChooseAuthentication (authenticationNames);
    if (Willing (&addr, connectionType, authenticationName, &status, type))
	send_willing (from, fromlen, authenticationName, &status);
    else
	if (type == QUERY)
	    send_unwilling (from, fromlen, authenticationName, &status);
    XdmcpDisposeARRAY8 (&status);
}

static void
indirect_respond (from, fromlen, length)
    struct sockaddr *from;
    int		    fromlen;
    int		    length;
{
    ARRAYofARRAY8   queryAuthenticationNames;
    ARRAY8	    clientAddress;
    ARRAY8	    clientPort;
    CARD16	    connectionType;
    int		    expectedLen;
    int		    i;
    XdmcpHeader	    header;
    int		    localHostAsWell;
    
    Debug ("Indirect respond %d\n", length);
    if (!XdmcpReadARRAYofARRAY8 (&buffer, &queryAuthenticationNames))
	return;
    expectedLen = 1;
    for (i = 0; i < (int)queryAuthenticationNames.length; i++)
	expectedLen += 2 + queryAuthenticationNames.data[i].length;
    if (length == expectedLen)
    {
	ClientAddress (from, &clientAddress, &clientPort, &connectionType);
	/*
	 * set up the forward query packet
	 */
    	header.version = XDM_PROTOCOL_VERSION;
    	header.opcode = (CARD16) FORWARD_QUERY;
    	header.length = 0;
    	header.length += 2 + clientAddress.length;
    	header.length += 2 + clientPort.length;
    	header.length += 1;
    	for (i = 0; i < (int)queryAuthenticationNames.length; i++)
	    header.length += 2 + queryAuthenticationNames.data[i].length;
    	XdmcpWriteHeader (&buffer, &header);
    	XdmcpWriteARRAY8 (&buffer, &clientAddress);
    	XdmcpWriteARRAY8 (&buffer, &clientPort);
    	XdmcpWriteARRAYofARRAY8 (&buffer, &queryAuthenticationNames);

	localHostAsWell = ForEachMatchingIndirectHost (&clientAddress, connectionType, sendForward, (char *) 0);
	
	XdmcpDisposeARRAY8 (&clientAddress);
	XdmcpDisposeARRAY8 (&clientPort);
	if (localHostAsWell)
	    all_query_respond (from, fromlen, &queryAuthenticationNames,
			   INDIRECT_QUERY);
    }
    else
    {
	Debug ("Indirect length error got %d expect %d\n", length, expectedLen);
    }
    XdmcpDisposeARRAYofARRAY8 (&queryAuthenticationNames);
}

static void
ProcessRequestSocket ()
{
    XdmcpHeader		header;
    struct sockaddr_in	addr;
    int			addrlen = sizeof addr;

    Debug ("ProcessRequestSocket\n");
    bzero ((char *) &addr, sizeof (addr));
    if (!XdmcpFill (xdmcpFd, &buffer, &addr, &addrlen)) {
	Debug ("XdmcpFill failed\n");
	return;
    }
    if (!XdmcpReadHeader (&buffer, &header)) {
	Debug ("XdmcpReadHeader failed\n");
	return;
    }
    if (header.version != XDM_PROTOCOL_VERSION) {
	Debug ("XDMCP header version read was %d, expected %d\n",
	       header.version, XDM_PROTOCOL_VERSION);
	return;
    }
    Debug ("header: %d %d %d\n", header.version, header.opcode, header.length);
    switch (header.opcode)
    {
    case BROADCAST_QUERY:
	broadcast_respond (&addr, addrlen, header.length);
	break;
    case QUERY:
	query_respond (&addr, addrlen, header.length);
	break;
    case INDIRECT_QUERY:
	indirect_respond (&addr, addrlen, header.length);
	break;
    case FORWARD_QUERY:
	forward_respond (&addr, addrlen, header.length);
	break;
    case REQUEST:
	request_respond (&addr, addrlen, header.length);
	break;
    case MANAGE:
	manage (&addr, addrlen, header.length);
	break;
    case KEEPALIVE:
	send_alive (&addr, addrlen, header.length);
	break;
    }
}

WaitForSomething ()
{
    FD_TYPE	reads;
    int	nready;
    extern int Rescan, ChildReady;

    Debug ("WaitForSomething\n");
    if (AnyWellKnownSockets () && !ChildReady) {
	reads = WellKnownSocketsMask;
	nready = select (WellKnownSocketsMax + 1, &reads, 0, 0, 0);
	Debug ("select returns %d.  Rescan: %d  ChildReady: %d\n",
		nready, Rescan, ChildReady);
	if (nready > 0)
	{
	    if (xdmcpFd >= 0 && FD_ISSET (xdmcpFd, &reads))
		ProcessRequestSocket ();
	    if (chooserFd >= 0 && FD_ISSET (chooserFd, &reads))
		ProcessChooserSocket (chooserFd);
	}
	if (ChildReady)
	{
	    WaitForChild ();
	}
    } else
	WaitForChild ();
}

/*
 * respond to a request on the UDP socket.
 */

static ARRAY8	Hostname;

void
registerHostname (name, namelen)
    char    *name;
    int	    namelen;
{
    int	i;

    if (!XdmcpReallocARRAY8 (&Hostname, namelen))
	return;
    for (i = 0; i < namelen; i++)
	Hostname.data[i] = name[i];
}

static void
direct_query_respond (from, fromlen, length, type)
    struct sockaddr *from;
    int		    fromlen;
    int		    length;
    xdmOpCode	    type;
{
    ARRAYofARRAY8   queryAuthenticationNames;
    int		    expectedLen;
    int		    i;
    
    if (!XdmcpReadARRAYofARRAY8 (&buffer, &queryAuthenticationNames))
	return;
    expectedLen = 1;
    for (i = 0; i < (int)queryAuthenticationNames.length; i++)
	expectedLen += 2 + queryAuthenticationNames.data[i].length;
    if (length == expectedLen)
	all_query_respond (from, fromlen, &queryAuthenticationNames, type);
    XdmcpDisposeARRAYofARRAY8 (&queryAuthenticationNames);
}

query_respond (from, fromlen, length)
    struct sockaddr *from;
    int		    fromlen;
    int		    length;
{
    Debug ("Query respond %d\n", length);
    direct_query_respond (from, fromlen, length, QUERY);
}

broadcast_respond (from, fromlen, length)
    struct sockaddr *from;
    int		    fromlen;
    int		    length;
{
    direct_query_respond (from, fromlen, length, BROADCAST_QUERY);
}

/* computes an X display name */

static char *
NetworkAddressToName(connectionType, connectionAddress, displayNumber)
    CARD16	connectionType;
    ARRAY8Ptr   connectionAddress;
    CARD16	displayNumber;
{
    switch (connectionType)
    {
    case FamilyInternet:
	{
	    CARD8		*data;
	    struct hostent	*hostent;
	    char		*name;
	    char		*localhost, *localHostname();

	    data = connectionAddress->data;
	    hostent = gethostbyaddr ((char *)data,
				     connectionAddress->length, AF_INET);

	    localhost = localHostname ();

	    /* 
	     * protect against bogus host names 
	     */
	    if (hostent && hostent->h_name && hostent->h_name[0]
			&& (hostent->h_name[0] != '.'))
	    {
		if (!strcmp (localhost, hostent->h_name))
		{
		    if (!getString (name, 10))
			return 0;
		    sprintf (name, ":%d", displayNumber);
		}
		else
		{
		    if (removeDomainname)
		    {
		    	char    *localDot, *remoteDot;
    
			/* check for a common domain name.  This
			 * could reduce names by recognising common
			 * super-domain names as well, but I don't think
			 * this is as useful, and will confuse more
			 * people
 			 */
		    	if ((localDot = strchr(localhost, '.')) &&
		            (remoteDot = strchr(hostent->h_name, '.')))
			{
			    /* smash the name in place; it won't
			     * be needed later.
			     */
			    if (!strcmp (localDot+1, remoteDot+1))
				*remoteDot = '\0';
			}
		    }

		    if (!getString (name, strlen (hostent->h_name) + 10))
			return 0;
		    sprintf (name, "%s:%d", hostent->h_name, displayNumber);
		}
	    }
	    else
	    {
		if (!getString (name, 25))
		    return 0;
		sprintf(name, "%d.%d.%d.%d:%d",
			data[0], data[1], data[2], data[3], displayNumber);
	    }
	    return name;
	}
#ifdef DNET
    case FamilyDECnet:
	return NULL;
#endif /* DNET */
    default:
	return NULL;
    }
}

/*ARGSUSED*/
forward_respond (from, fromlen, length)
    struct sockaddr	*from;
    int			fromlen;
    int			length;
{
    ARRAY8	    clientAddress;
    ARRAY8	    clientPort;
    ARRAYofARRAY8   authenticationNames;
    struct sockaddr *client;
    int		    clientlen;
    int		    expectedLen;
    int		    i;
    
    Debug ("Forward respond %d\n", length);
    clientAddress.length = 0;
    clientAddress.data = 0;
    clientPort.length = 0;
    clientPort.data = 0;
    authenticationNames.length = 0;
    authenticationNames.data = 0;
    if (XdmcpReadARRAY8 (&buffer, &clientAddress) &&
	XdmcpReadARRAY8 (&buffer, &clientPort) &&
	XdmcpReadARRAYofARRAY8 (&buffer, &authenticationNames))
    {
	expectedLen = 0;
	expectedLen += 2 + clientAddress.length;
	expectedLen += 2 + clientPort.length;
	expectedLen += 1;	    /* authenticationNames */
	for (i = 0; i < (int)authenticationNames.length; i++)
	    expectedLen += 2 + authenticationNames.data[i].length;
	if (length == expectedLen)
	{
	    int	j;

	    j = 0;
	    for (i = 0; i < (int)clientPort.length; i++)
		j = j * 256 + clientPort.data[i];
	    Debug ("Forward client address (port %d)", j);
	    for (i = 0; i < (int)clientAddress.length; i++)
		Debug (" %d", clientAddress.data[i]);
	    Debug ("\n");
    	    switch (from->sa_family)
    	    {
#ifdef AF_INET
	    case AF_INET:
		{
		    struct sockaddr_in	in_addr;

		    if (clientAddress.length != 4 ||
		        clientPort.length != 2)
		    {
			goto badAddress;
		    }
		    bzero ((char *) &in_addr, sizeof (in_addr));
#ifdef BSD44SOCKETS
		    in_addr.sin_len = sizeof(in_addr);
#endif
		    in_addr.sin_family = AF_INET;
		    memmove( &in_addr.sin_addr, clientAddress.data, 4);
		    memmove( (char *) &in_addr.sin_port, clientPort.data, 2);
		    client = (struct sockaddr *) &in_addr;
		    clientlen = sizeof (in_addr);
		    all_query_respond (client, clientlen, &authenticationNames,
			       FORWARD_QUERY);
		}
		break;
#endif
#ifdef AF_UNIX
	    case AF_UNIX:
		{
		    struct sockaddr_un	un_addr;

		    if (clientAddress.length >= sizeof (un_addr.sun_path))
			goto badAddress;
		    bzero ((char *) &un_addr, sizeof (un_addr));
		    un_addr.sun_family = AF_UNIX;
		    memmove( un_addr.sun_path, clientAddress.data, clientAddress.length);
		    un_addr.sun_path[clientAddress.length] = '\0';
		    client = (struct sockaddr *) &un_addr;
#ifdef BSD44SOCKETS
		    un_addr.sun_len = strlen(un_addr.sun_path);
		    clientlen = SUN_LEN(&un_addr);
#else
		    clientlen = sizeof (un_addr);
#endif
		    all_query_respond (client, clientlen, &authenticationNames,
			       FORWARD_QUERY);
		}
		break;
#endif
#ifdef AF_CHAOS
	    case AF_CHAOS:
		goto badAddress;
#endif
#ifdef AF_DECnet
	    case AF_DECnet:
		goto badAddress;
#endif
    	    }
	}
	else
	{
	    Debug ("Forward length error got %d expect %d\n", length, expectedLen);
	}
    }
badAddress:
    XdmcpDisposeARRAY8 (&clientAddress);
    XdmcpDisposeARRAY8 (&clientPort);
    XdmcpDisposeARRAYofARRAY8 (&authenticationNames);
}

send_willing (from, fromlen, authenticationName, status)
    struct sockaddr *from;
    int		    fromlen;
    ARRAY8Ptr	    authenticationName;
    ARRAY8Ptr	    status;
{
    XdmcpHeader	header;

    Debug ("Send willing %*.*s %*.*s\n", authenticationName->length,
					 authenticationName->length,
					 pS(authenticationName->data),
					 status->length,
					 status->length,
					 pS(status->data));
    header.version = XDM_PROTOCOL_VERSION;
    header.opcode = (CARD16) WILLING;
    header.length = 6 + authenticationName->length +
		    Hostname.length + status->length;
    XdmcpWriteHeader (&buffer, &header);
    XdmcpWriteARRAY8 (&buffer, authenticationName);
    XdmcpWriteARRAY8 (&buffer, &Hostname);
    XdmcpWriteARRAY8 (&buffer, status);
    XdmcpFlush (xdmcpFd, &buffer, from, fromlen);
}

send_unwilling (from, fromlen, authenticationName, status)
    struct sockaddr *from;
    int		    fromlen;
    ARRAY8Ptr	    authenticationName;
    ARRAY8Ptr	    status;
{
    XdmcpHeader	header;

    Debug ("Send unwilling %*.*s %*.*s\n", authenticationName->length,
					 authenticationName->length,
					 pS(authenticationName->data),
					 status->length,
					 status->length,
					 pS(status->data));
    header.version = XDM_PROTOCOL_VERSION;
    header.opcode = (CARD16) UNWILLING;
    header.length = 4 + Hostname.length + status->length;
    XdmcpWriteHeader (&buffer, &header);
    XdmcpWriteARRAY8 (&buffer, &Hostname);
    XdmcpWriteARRAY8 (&buffer, status);
    XdmcpFlush (xdmcpFd, &buffer, from, fromlen);
}

static unsigned long	globalSessionID;

#define NextSessionID()    (++globalSessionID)

void init_session_id()
{
    /* Set randomly so we are unlikely to reuse id's from a previous
     * incarnation so we don't say "Alive" to those displays.
     * Start with low digits 0 to make debugging easier.
     */
    globalSessionID = (time((Time_t)0)&0x7fff) * 16000;
}
    
static ARRAY8 outOfMemory = { (CARD16) 13, (CARD8Ptr) "Out of memory" };
static ARRAY8 noValidAddr = { (CARD16) 16, (CARD8Ptr) "No valid address" };
static ARRAY8 noValidAuth = { (CARD16) 22, (CARD8Ptr) "No valid authorization" };
static ARRAY8 noAuthentic = { (CARD16) 29, (CARD8Ptr) "XDM has no authentication key" };

request_respond (from, fromlen, length)
    struct sockaddr *from;
    int		    fromlen;
    int		    length;
{
    CARD16	    displayNumber;
    ARRAY16	    connectionTypes;
    ARRAYofARRAY8   connectionAddresses;
    ARRAY8	    authenticationName;
    ARRAY8	    authenticationData;
    ARRAYofARRAY8   authorizationNames;
    ARRAY8	    manufacturerDisplayID;
    ARRAY8Ptr	    reason;
    int		    expectlen;
    int		    i, j;
    struct protoDisplay  *pdpy;
    ARRAY8	    authorizationName, authorizationData;
    ARRAY8Ptr	    connectionAddress;

    Debug ("Request respond %d\n", length);
    connectionTypes.data = 0;
    connectionAddresses.data = 0;
    authenticationName.data = 0;
    authenticationData.data = 0;
    authorizationNames.data = 0;
    authorizationName.length = 0;
    authorizationData.length = 0;
    manufacturerDisplayID.data = 0;
    if (XdmcpReadCARD16 (&buffer, &displayNumber) &&
	XdmcpReadARRAY16 (&buffer, &connectionTypes) &&
	XdmcpReadARRAYofARRAY8 (&buffer, &connectionAddresses) &&
	XdmcpReadARRAY8 (&buffer, &authenticationName) &&
	XdmcpReadARRAY8 (&buffer, &authenticationData) &&
	XdmcpReadARRAYofARRAY8 (&buffer, &authorizationNames) &&
	XdmcpReadARRAY8 (&buffer, &manufacturerDisplayID))
    {
	expectlen = 0;
	expectlen += 2;				    /* displayNumber */
	expectlen += 1 + 2*connectionTypes.length;  /* connectionTypes */
	expectlen += 1;				    /* connectionAddresses */
	for (i = 0; i < (int)connectionAddresses.length; i++)
	    expectlen += 2 + connectionAddresses.data[i].length;
	expectlen += 2 + authenticationName.length; /* authenticationName */
	expectlen += 2 + authenticationData.length; /* authenticationData */
	expectlen += 1;				    /* authoriationNames */
	for (i = 0; i < (int)authorizationNames.length; i++)
	    expectlen += 2 + authorizationNames.data[i].length;
	expectlen += 2 + manufacturerDisplayID.length;	/* displayID */
	if (expectlen != length)
	{
	    Debug ("Request length error got %d expect %d\n", length, expectlen);
	    goto abort;
	}
	if (connectionTypes.length == 0 ||
	    connectionAddresses.length != connectionTypes.length)
	{
	    reason = &noValidAddr;
	    pdpy = 0;
	    goto decline;
	}
	pdpy = FindProtoDisplay (from, fromlen, displayNumber);
	if (!pdpy) {

	    /* Check this Display against the Manager's policy */
	    reason = Accept (from, fromlen, displayNumber);
	    if (reason)
		goto decline;

	    /* Check the Display's stream services against Manager's policy */
	    i = SelectConnectionTypeIndex (&connectionTypes,
					   &connectionAddresses);
	    if (i < 0) {
		reason = &noValidAddr;
		goto decline;
	    }
	
	    /* The Manager considers this a new session */
	    connectionAddress = &connectionAddresses.data[i];
	    pdpy = NewProtoDisplay (from, fromlen, displayNumber,
				    connectionTypes.data[i], connectionAddress,
				    NextSessionID());
	    Debug ("NewProtoDisplay 0x%x\n", pdpy);
	    if (!pdpy) {
		reason = &outOfMemory;
		goto decline;
	    }
	}
	if (authorizationNames.length == 0)
	    j = 0;
	else
	    j = SelectAuthorizationTypeIndex (&authenticationName,
					      &authorizationNames);
	if (j < 0)
	{
	    reason = &noValidAuth;
	    goto decline;
	}
	if (!CheckAuthentication (pdpy,
				  &manufacturerDisplayID,
				  &authenticationName,
				  &authenticationData))
	{
	    reason = &noAuthentic;
	    goto decline;
	}
	if (j < (int)authorizationNames.length)
	{
	    Xauth   *auth;
	    SetProtoDisplayAuthorization (pdpy,
		(unsigned short) authorizationNames.data[j].length,
		(char *) authorizationNames.data[j].data);
	    auth = pdpy->xdmcpAuthorization;
	    if (!auth)
		auth = pdpy->fileAuthorization;
	    if (auth)
	    {
		authorizationName.length = auth->name_length;
		authorizationName.data = (CARD8Ptr) auth->name;
		authorizationData.length = auth->data_length;
		authorizationData.data = (CARD8Ptr) auth->data;
	    }
	}
	if (pdpy)
	{
	    send_accept (from, fromlen, pdpy->sessionID,
				        &authenticationName,
					&authenticationData,
					&authorizationName,
					&authorizationData);
	}
	else
	{
decline:    ;
	    send_decline (from, fromlen, &authenticationName,
				 &authenticationData,
				 reason);
            if (pdpy)
		DisposeProtoDisplay (pdpy);
	}
    }
abort:
    XdmcpDisposeARRAY16 (&connectionTypes);
    XdmcpDisposeARRAYofARRAY8 (&connectionAddresses);
    XdmcpDisposeARRAY8 (&authenticationName);
    XdmcpDisposeARRAY8 (&authenticationData);
    XdmcpDisposeARRAYofARRAY8 (&authorizationNames);
    XdmcpDisposeARRAY8 (&manufacturerDisplayID);
}

send_accept (to, tolen, sessionID,
	     authenticationName, authenticationData,
	     authorizationName, authorizationData)
    struct sockaddr *to;
    int		    tolen;
    CARD32	    sessionID;
    ARRAY8Ptr	    authenticationName, authenticationData;
    ARRAY8Ptr	    authorizationName, authorizationData;
{
    XdmcpHeader	header;

    Debug ("Accept Session ID %d\n", sessionID);
    header.version = XDM_PROTOCOL_VERSION;
    header.opcode = (CARD16) ACCEPT;
    header.length = 4;			    /* session ID */
    header.length += 2 + authenticationName->length;
    header.length += 2 + authenticationData->length;
    header.length += 2 + authorizationName->length;
    header.length += 2 + authorizationData->length;
    XdmcpWriteHeader (&buffer, &header);
    XdmcpWriteCARD32 (&buffer, sessionID);
    XdmcpWriteARRAY8 (&buffer, authenticationName);
    XdmcpWriteARRAY8 (&buffer, authenticationData);
    XdmcpWriteARRAY8 (&buffer, authorizationName);
    XdmcpWriteARRAY8 (&buffer, authorizationData);
    XdmcpFlush (xdmcpFd, &buffer, to, tolen);
}
   
send_decline (to, tolen, authenticationName, authenticationData, status)
    struct sockaddr *to;
    int		    tolen;
    ARRAY8Ptr	    authenticationName, authenticationData;
    ARRAY8Ptr	    status;
{
    XdmcpHeader	header;

    Debug ("Decline %*.*s\n", status->length, status->length, pS(status->data));
    header.version = XDM_PROTOCOL_VERSION;
    header.opcode = (CARD16) DECLINE;
    header.length = 0;
    header.length += 2 + status->length;
    header.length += 2 + authenticationName->length;
    header.length += 2 + authenticationData->length;
    XdmcpWriteHeader (&buffer, &header);
    XdmcpWriteARRAY8 (&buffer, status);
    XdmcpWriteARRAY8 (&buffer, authenticationName);
    XdmcpWriteARRAY8 (&buffer, authenticationData);
    XdmcpFlush (xdmcpFd, &buffer, to, tolen);
}

manage (from, fromlen, length)
    struct sockaddr *from;
    int		    fromlen;
    int		    length;
{
    CARD32		sessionID;
    CARD16		displayNumber;
    ARRAY8		displayClass;
    int			expectlen;
    struct protoDisplay	*pdpy;
    struct display	*d;
    char		*name = NULL;
    char		*class = NULL;
    XdmcpNetaddr	from_save;
    ARRAY8		clientAddress, clientPort;
    CARD16		connectionType;

    Debug ("Manage %d\n", length);
    displayClass.data = 0;
    displayClass.length = 0;
    if (XdmcpReadCARD32 (&buffer, &sessionID) &&
	XdmcpReadCARD16 (&buffer, &displayNumber) &&
	XdmcpReadARRAY8 (&buffer, &displayClass))
    {
	expectlen = 4 +				/* session ID */
		    2 +				/* displayNumber */
		    2 + displayClass.length;	/* displayClass */
	if (expectlen != length)
	{
	    Debug ("Manage length error got %d expect %d\n", length, expectlen);
	    goto abort;
	}
	pdpy = FindProtoDisplay (from, fromlen, displayNumber);
	Debug ("Manage Session ID %d, pdpy 0x%x\n", sessionID, pdpy);
	if (!pdpy || pdpy->sessionID != sessionID)
	{
	    /*
	     * We may have already started a session for this display
	     * but it hasn't seen the response in the form of an
	     * XOpenDisplay() yet. So check if it is in the list of active
	     * displays, and if so check that the session id's match.
	     * If all this is true, then we have a duplicate request that
	     * can be ignored.
	     */
	    if (!pdpy 
		&& (d = FindDisplayByAddress(from, fromlen, displayNumber))
		&& d->sessionID == sessionID) {
		     Debug("manage: got duplicate pkt, ignoring\n");
		     goto abort;
	    }
	    Debug ("Session ID %d refused\n", sessionID);
	    if (pdpy)
		Debug ("Existing Session ID %d\n", pdpy->sessionID);
	    send_refuse (from, fromlen, sessionID);
	}
	else
	{
	    name = NetworkAddressToName (pdpy->connectionType,
					 &pdpy->connectionAddress,
					 pdpy->displayNumber);
	    Debug ("Computed display name: %s\n", name);
	    if (!name)
	    {
		send_failed (from, fromlen, "(no name)", sessionID, "out of memory");
		goto abort;
	    }
	    d = FindDisplayByName (name);
	    if (d)
	    {
		extern void StopDisplay ();

		Debug ("Terminating active session for %s\n", d->name);
		StopDisplay (d);
	    }
	    class = malloc (displayClass.length + 1);
	    if (!class)
	    {
		send_failed (from, fromlen, name, sessionID, "out of memory");
		goto abort;
	    }
	    if (displayClass.length)
	    {
		memmove( class, displayClass.data, displayClass.length);
		class[displayClass.length] = '\0';
	    }
	    else
	    {
		free ((char *) class);
		class = (char *) NULL;
	    }
	    from_save = (XdmcpNetaddr) malloc (fromlen);
	    if (!from_save)
	    {
		send_failed (from, fromlen, name, sessionID, "out of memory");
		goto abort;
	    }
	    memmove( from_save, from, fromlen);
	    d = NewDisplay (name, class);
	    if (!d)
	    {
		free ((char *) from_save);
		send_failed (from, fromlen, name, sessionID, "out of memory");
		goto abort;
	    }
	    d->displayType.location = Foreign;
	    d->displayType.lifetime = Transient;
	    d->displayType.origin = FromXDMCP;
	    d->sessionID = pdpy->sessionID;
	    d->from = from_save;
	    d->fromlen = fromlen;
	    d->displayNumber = pdpy->displayNumber;
	    ClientAddress (from, &clientAddress, &clientPort, &connectionType);
	    d->useChooser = 0;
	    if (IsIndirectClient (&clientAddress, connectionType))
	    {
		Debug ("IsIndirectClient\n");
		ForgetIndirectClient (&clientAddress, connectionType);
		if (UseChooser (&clientAddress, connectionType))
		{
		    d->useChooser = 1;
		    Debug ("Use chooser for %s\n", d->name);
		}
	    }
	    d->clientAddr = clientAddress;
	    d->connectionType = connectionType;
	    XdmcpDisposeARRAY8 (&clientPort);
	    if (pdpy->fileAuthorization)
	    {
		d->authorizations = (Xauth **) malloc (sizeof (Xauth *));
		if (!d->authorizations)
		{
		    free ((char *) from_save);
		    free ((char *) d);
		    send_failed (from, fromlen, name, sessionID, "out of memory");
		    goto abort;
		}
		d->authorizations[0] = pdpy->fileAuthorization;
		d->authNum = 1;
		pdpy->fileAuthorization = 0;
	    }
	    DisposeProtoDisplay (pdpy);
	    Debug ("Starting display %s,%s\n", d->name, d->class);
	    StartDisplay (d);
	}
    }
abort:
    XdmcpDisposeARRAY8 (&displayClass);
    if (name) free ((char*) name);
    if (class) free ((char*) class);
}

SendFailed (d, reason)
    struct display  *d;
    char	    *reason;
{
    Debug ("Display start failed, sending Failed\n");
    send_failed (d->from, d->fromlen, d->name, d->sessionID, reason);
}

send_failed (from, fromlen, name, sessionID, reason)
    struct sockaddr *from;
    int		    fromlen;
    char	    *name;
    CARD32	    sessionID;
    char	    *reason;
{
    static char	buf[256];
    XdmcpHeader	header;
    ARRAY8	status;

    sprintf (buf, "Session %d failed for display %s: %s",
	     sessionID, name, reason);
    Debug ("Send failed %d %s\n", sessionID, buf);
    status.length = strlen (buf);
    status.data = (CARD8Ptr) buf;
    header.version = XDM_PROTOCOL_VERSION;
    header.opcode = (CARD16) FAILED;
    header.length = 6 + status.length;
    XdmcpWriteHeader (&buffer, &header);
    XdmcpWriteCARD32 (&buffer, sessionID);
    XdmcpWriteARRAY8 (&buffer, &status);
    XdmcpFlush (xdmcpFd, &buffer, from, fromlen);
}

send_refuse (from, fromlen, sessionID)
    struct sockaddr *from;
    int		    fromlen;
    CARD32	    sessionID;
{
    XdmcpHeader	header;

    Debug ("Send refuse %d\n", sessionID);
    header.version = XDM_PROTOCOL_VERSION;
    header.opcode = (CARD16) REFUSE;
    header.length = 4;
    XdmcpWriteHeader (&buffer, &header);
    XdmcpWriteCARD32 (&buffer, sessionID);
    XdmcpFlush (xdmcpFd, &buffer, from, fromlen);
}

send_alive (from, fromlen, length)
    struct sockaddr *from;
    int		    fromlen;
    int		    length;
{
    CARD32		sessionID;
    CARD16		displayNumber;
    struct display	*d;
    XdmcpHeader		header;
    CARD8		sendRunning;
    CARD32		sendSessionID;

    Debug ("Send alive\n");
    if (XdmcpReadCARD16 (&buffer, &displayNumber) &&
	XdmcpReadCARD32 (&buffer, &sessionID))
    {
	if (length == 6)
	{
	    d = FindDisplayBySessionID (sessionID);
	    if (!d) {
		d = FindDisplayByAddress (from, fromlen, displayNumber);
	    }
	    sendRunning = 0;
	    sendSessionID = 0;
	    if (d && d->status == running)
 	    {
		if (d->sessionID == sessionID)
		    sendRunning = 1;
		sendSessionID = d->sessionID;
	    }
	    header.version = XDM_PROTOCOL_VERSION;
	    header.opcode = (CARD16) ALIVE;
	    header.length = 5;
	    Debug ("alive: %d %d\n", sendRunning, sendSessionID);
	    XdmcpWriteHeader (&buffer, &header);
	    XdmcpWriteCARD8 (&buffer, sendRunning);
	    XdmcpWriteCARD32 (&buffer, sendSessionID);
	    XdmcpFlush (xdmcpFd, &buffer, from, fromlen);
	}
    }
}

char *
NetworkAddressToHostname (connectionType, connectionAddress)
    CARD16	connectionType;
    ARRAY8Ptr   connectionAddress;
{
    char    *name = 0;

    switch (connectionType)
    {
    case FamilyInternet:
	{
	    struct hostent	*hostent;
	    char dotted[20];
	    char *local_name;

	    hostent = gethostbyaddr ((char *)connectionAddress->data,
				     connectionAddress->length, AF_INET);

	    if (hostent)
		local_name = hostent->h_name;
	    else {
		/* can't get name, so use emergency fallback */
		sprintf(dotted, "%d.%d.%d.%d",
			connectionAddress->data[0],
			connectionAddress->data[1],
			connectionAddress->data[2],
			connectionAddress->data[3]);
		local_name = dotted;
		LogError ("Cannot convert Internet address %s to host name\n",
			  dotted);
	    }
	    if (!getString (name, strlen (local_name)))
		break;
	    strcpy (name, local_name);
	    break;
	}
#ifdef DNET
    case FamilyDECnet:
	break;
#endif /* DNET */
    default:
	break;
    }
    return name;
}

static
HostnameToNetworkAddress (name, connectionType, connectionAddress)
char	    *name;
CARD16	    connectionType;
ARRAY8Ptr   connectionAddress;
{
    switch (connectionType)
    {
    case FamilyInternet:
	{
	    struct hostent	*hostent;

	    hostent = gethostbyname (name);
	    if (!hostent)
		return FALSE;
	    if (!XdmcpAllocARRAY8 (connectionAddress, hostent->h_length))
		return FALSE;
	    memmove( connectionAddress->data, hostent->h_addr, hostent->h_length);
	    return TRUE;
	}
#ifdef DNET
    case FamilyDECnet:
	return FALSE;
#endif
    }
    return FALSE;
}

/*
 * converts a display name into a network address, using
 * the same rules as XOpenDisplay (algorithm cribbed from there)
 */

static
NameToNetworkAddress(name, connectionTypep, connectionAddress, displayNumber)
char	    *name;
CARD16Ptr   connectionTypep;
ARRAY8Ptr   connectionAddress;
CARD16Ptr   displayNumber;
{
    char    *colon, *display_number;
    char    hostname[1024];
    int	    dnet = FALSE;
    CARD16  number;
    CARD16  connectionType;

    colon = strchr(name, ':');
    if (!colon)
	return FALSE;
    if (colon != name)
    {
	if (colon - name > sizeof (hostname))
	    return FALSE;
	strncpy (hostname, name, colon - name);
	hostname[colon - name] = '\0';
    }
    else
    {
	strcpy (hostname, localHostname ());
    }
    if (colon[1] == ':')
    {
	dnet = TRUE;
	colon++;
    }
#ifndef DNETCONN
    if (dnet)
	return FALSE;
#endif
    display_number = colon + 1;
    while (*display_number && *display_number != '.')
    {
	if (!isascii (*display_number) || !isdigit(*display_number))
	    return FALSE;
    }
    if (display_number == colon + 1)
	return FALSE;
    number = atoi (colon + 1);
#ifdef DNETCONN
    if (dnet)
	connectionType = FamilyDECnet;
    else
#endif
	connectionType = FamilyInternet;
    if (!HostnameToNetworkAddress (hostname, connectionType, connectionAddress))
	return FALSE;
    *displayNumber = number;
    *connectionTypep = connectionType;
    return TRUE;
}

#endif /* XDMCP */