NAME
lbxproxy - Low BandWidth X proxy
SYNOPSIS
lbxproxy [:] [option]
DESCRIPTION
Applications that would like to take advantage of the Low Bandwidth
extension to X (LBX) must make their connections to an lbxproxy. These
applications need to know nothing about LBX, they simply connect to the
lbxproxy as if were a regular server. The lbxproxy accepts client
connections, multiplexes them over a single connection to the X server, and
performs various optimizations on the X protocol to make it faster over low
bandwidth and/or high latency connections.
With regard to authentication/authorization, lbxproxy simply passes along
to the server the credentials presented by the client. Since X clients will
connect to lbxproxy, it is important that the user's .Xauthority file contain
entries with valid keys associated with the network ID of the proxy. lbxproxy
does not get involved with how these entries are added to the .Xauthority file.
The user is responsible for setting it up.
The lbxproxy program has various options, all of which are optional.
If
:
is specified, the proxy will use the given display port when
listening for connections. The display port is an offset from port 6000,
identical to the way in which regular X display connections are specified.
If no port is specified on the command line option, lbxproxy will default
to port 63. If the port number that the proxy tries to listen on is in
use, the proxy will attempt to use another port number. If
the proxy is not using the Proxy Manager and the default
port number cannot be used, the port number that is used
will be written to stderr.
The other command line options that can be specified are:
-
-help
-
Prints a brief help message about the command line options.
-
-display _d_p_y
-
Specifies the address of the X server supporting the LBX extension.
If this option is not specified, the display is obtained by the
DISPLAY environment variable.
-
-motion _c_o_u_n_t
-
A limited number of pointer motion events are allowed to be in flight
between the server and the proxy at any given time. The maximum
number of motion events that can be in flight is set with this option;
the default is 8.
-
-maxservers _n_u_m_b_e_r
-
The default behavior of lbxproxy is to manage a single server.
However, lbxproxy can manage more than one server. The default
maximum number of servers is 20. The number of servers can be
overridden by setting the environment variable LBXPROXY_MAXSERVERS
to the desired number. The order of precedence from highest
to lowest: command line, environment variable, default number.
-
-[terminate|reset]
-
The default behavior of lbxproxy is to continue running as usual when
it's last client exits. The
-terminate
option will cause lbxproxy to
exit when the last client exits. The
-reset
option will cause
lbxproxy to reset itself when the last client exits. Resetting causes
lbxproxy to clean up it's state and reconnect to the server.
-
-reconnect
-
The default behavior of lbxproxy is to exit when its connection to the
server is broken. The
-reconnect
option will cause lbxproxy to just reset instead (see
-reset
above) and attempt to reconnect to the server.
-
-I
-
Causes all remaining arguments to be ignored.
-
-nolbx
-
Disables all LBX optimizations.
-
-nocomp
-
Disables stream compression.
-
-nodelta
-
Disables delta request substitutions.
-
-notags
-
Disables usage of tags.
-
-nogfx
-
Disables reencoding of graphics requests (not including image
related requests).
-
-noimage
-
Disables image compression.
-
-nosquish
-
Disables squishing of X events.
-
-nointernsc
-
Disables short circuiting of InternAtom requests.
-
-noatomsfile
-
Disables reading of the atoms control file. See the section on
"Atom Control" for more details.
-
-atomsfile _f_i_l_e
-
Overrides the default AtomControl file. See the section on
"Atom Control" for more details.
-
-nowinattr
-
Disables GetWindowAttributes/GetGeometry grouping into one round trip.
-
-nograbcmap
-
Disables colormap grabbing.
-
-norgbfile
-
Disables color name to RGB resolution in proxy.
-
-rgbfile _p_a_t_h
-
Specifies an alternate RGB database for color name to RGB resolution.
-
-tagcachesize
-
Set the size of the proxy's tag cache (in bytes).
-
-zlevel _l_e_v_e_l
-
Set the Zlib compression level (used for stream compression).
default is 6
1 = worst compression, fastest
9 = best compression, slowest
-
-compstats
-
Report stream compression statistics every time the proxy resets
or receives a SIGHUP signal.
-
-nozeropad
-
Don't zero out unused pad bytes in X requests, replies, and events.
-
-cheaterrors
-
Allows cheating on X protocol for the sake of improved performance.
The X protocol guarantees that any replies, events or
errors generated by a previous request will be sent before those of
a later request. This puts substantial restrictions on when lbxproxy
can short circuit a request. The -cheaterrors option allows lbxproxy to
violate X protocol rules with respect to errors. Use at your own risk.
-
-cheatevents
-
The -cheatevents option allows lbxproxy to violate X protocol rules with
respect to events as well as errors. Use at your own risk.
ATOM CONTROL
At startup, lbxproxy "pre-interns" a configurable list of
atoms. This allows lbxproxy to intern a group of atoms in a single round
trip and immediately store the results in its cache.
While running, lbxproxy uses heuristics to decide when to delay
sending window property data to the server. The heuristics depend
on the size of the data, the name of the property, and whether a
window manager is running through the same lbxproxy.
Atom control is specified in the "AtomControl" file, set
up during installation of lbxproxy, with command line overrides.
The file is a simple text file. There are three forms of lines:
comments, length control, and name control. Lines starting with
a '!' are treated as comments. A line of the form
z _l_e_n_g_t_h
specifies the minimum length in bytes before property data will be
delayed. A line of the form
_o_p_t_i_o_n_s _a_t_o_m_n_a_m_e
controls the given atom, where _o_p_t_i_o_n_s is any combination
of the following characters: 'i' means the atom should be pre-interned;
and 'w' means data for properties with this name should be delayed only
if a window manager is also running through the same lbxproxy.
BUGS
When the authorization protocol XDM-AUTHORIZATION-1 is used:
A client must be on the same host as lbxproxy for the client to be
authorized to connect to the server.
If a client is not on the same host as lbxproxy, the client will
not be authorized to connect to the server.