dix: Extend initial connection handshake for forwarding proxies

 commit 78fa121f4097d29458e5453c13473595df06e26e
 Author: Adam Jackson <ajax@redhat.com>
 Date:   Fri Jun 17 13:43:38 2011 -0400

    dix: Extend initial connection handshake for forwarding proxies

    Forwarding proxies like sshd will appear to be local, even though they
    aren't really.  This leads to weird behaviour for extensions that truly
    require running under the same OS services as the client, like MIT-SHM
    and DRI2.

    Add two new legal values for the initial connection's byteOrder field,
    'r' and 'R'.  These act like 'l' and 'B' respectively, but have the side
    effect of forcing the client to be treated as non-local.  Forwarding
    proxies should attempt to munge the first packet of the connection
    accordingly; older servers will reject connections thusly munged, so the
    proxy should fall back to passthrough if the munged connection attempt
    fails.

    Reviewed-by: Daniel Stone <daniel@fooishbar.org>
    Signed-off-by: Adam Jackson <ajax@redhat.com>

 Backported-to-NX-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>

2 files changed, 14 insertions, 8 deletions

diff --git a/nx-X11/programs/Xserver/dix/dispatch.c b/nx-X11/programs/Xserver/dix/dispatch.c
index 16b94301f..438436526 100644
--- a/nx-X11/programs/Xserver/dix/dispatch.c
+++ b/nx-X11/programs/Xserver/dix/dispatch.c
@@ -3752,12 +3752,14 @@ ProcInitialConnection(register ClientPtr client)
     REQUEST(xReq);
     register xConnClientPrefix *prefix;
     int whichbyte = 1;
+    char order;
 
     prefix = (xConnClientPrefix *)((char *)stuff + sz_xReq);
-    if ((prefix->byteOrder != 'l') && (prefix->byteOrder != 'B'))
+    order = prefix->byteOrder;
+    if (order != 'l' && order != 'B' && order != 'r' && order != 'R')
 	return (client->noClientException = -1);
-    if (((*(char *) &whichbyte) && (prefix->byteOrder == 'B')) ||
-	(!(*(char *) &whichbyte) && (prefix->byteOrder == 'l')))
+    if (((*(char *) &whichbyte) && (order == 'B' || order == 'R')) ||
+	(!(*(char *) &whichbyte) && (order == 'l' || order == 'r')))
     {
 	client->swapped = TRUE;
 	SwapConnClientPrefix(prefix);
@@ -3769,6 +3771,10 @@ ProcInitialConnection(register ClientPtr client)
     {
 	swaps(&stuff->length);
     }
+    if (order == 'r' || order == 'R')
+    {
+	client->local = FALSE;
+    }
     ResetCurrentRequest(client);
     return (client->noClientException);
 }
diff --git a/nx-X11/programs/Xserver/os/connection.c b/nx-X11/programs/Xserver/os/connection.c
index 917f79fa6..d4627e97c 100644
--- a/nx-X11/programs/Xserver/os/connection.c
+++ b/nx-X11/programs/Xserver/os/connection.c
@@ -886,7 +886,7 @@ ErrorConnMax(XtransConnInfo trans_conn)
     xConnSetupPrefix csp;
     char pad[3];
     struct iovec iov[3];
-    char byteOrder = 0;
+    char order = 0;
     int whichbyte = 1;
     struct timeval waittime;
     fd_set mask;
@@ -899,16 +899,16 @@ ErrorConnMax(XtransConnInfo trans_conn)
     FD_SET(fd, &mask);
     (void)Select(fd + 1, &mask, NULL, NULL, &waittime);
     /* try to read the byte-order of the connection */
-    (void)_XSERVTransRead(trans_conn, &byteOrder, 1);
-    if ((byteOrder == 'l') || (byteOrder == 'B'))
+    (void)_XSERVTransRead(trans_conn, &order, 1);
+    if (order == 'l' || order == 'B' || order == 'r' || order == 'R')
     {
 	csp.success = xFalse;
 	csp.lengthReason = sizeof(NOROOM) - 1;
 	csp.length = (sizeof(NOROOM) + 2) >> 2;
 	csp.majorVersion = X_PROTOCOL;
 	csp.minorVersion = X_PROTOCOL_REVISION;
-	if (((*(char *) &whichbyte) && (byteOrder == 'B')) ||
-	    (!(*(char *) &whichbyte) && (byteOrder == 'l')))
+	if (((*(char *) &whichbyte) && (order == 'B' || order == 'R')) ||
+	    (!(*(char *) &whichbyte) && (order == 'l' || order == 'r')))
 	{
 	    swaps(&csp.majorVersion);
 	    swaps(&csp.minorVersion);