See Issue #2443.
When there's more than 2 rectangles in the region structure, region16_intersect_rect would calculate extents by all 'intersected' sub rectangles.
But it always extend the extents to (0,0) because it initialize the new extents as (0,0,0,0) and union later rectangles with this empty point by simple MIN/MAX calculation.
Also fixed rectangle_is_empty although it has not been used yet. The function does not work as its name.
Reuse norbert case. That case is enough for the intersect fix, but the expected result is not correct. The test case is also fixed.
Added test case to check empty rectangle.
Situation: we have fragmented TPKT PDU without two last bytes
(or one last byte - for fast-path) in network stack.
First call to transport_read_pdu() works normally, read
available bytes and exit with status 0 - no whole PDU readed.
Before second call this missed bytes arrive.
Optionally with next PDU.
In second call header parsing code unconditionally read this
two bytes(one byte) despite this is not header bytes.
And increase stream position, so stream now contains whole PDU.
This cause (pduLength - Stream_GetPosition(s)) calculation to be 0.
So transport_read_layer_bytes()-->transport_read_layer() return 0
and transport_read_pdu() exits with "not enough data is available"
status.
If next PDU isn't available next calls to transport_read_pdu()
give same result.
If next PDU arrive - (pduLength - Stream_GetPosition(s)) will be
less than 0. Stream position will grow, grow and grow on each call.
And transport_read_pdu() never signals that PDU is readed.
Caught on Android FreeRDP client with high RDP traffic (several MBytes/s).
1. Don't draw to screen if server sends begin/end paint
messages without any real updates.
2. Redraw only summary region that covers really invalidated
part of screen.
Keepalive settings are usually (depending on the implementation) only
used if the TCP connection is idle.
If the network is interrupted/disconnected/... click or keyboard input
generates outgoing traffic therefore the connection isn't idle
anymore and keepalives might not be used causing the connection to
stay open and the client to stall.
Linux 2.6.36 added a TCP_USER_TIMEOUT TCP socket option that lets a
program specify the maximum time transmitted data may remain
unacknowledged before TCP will close the corresponding connection with
ETIMEDOUT.
Setting TCP_USER_TIMEOUT allows us to detect a network problem (like
cable disconnect) even if the connection isn't idle.
refreshRectSupport and suppressOutputSupport of the General
Capability Set (MS-RDPBCGR 2.2.7.1.1) are server-only flags
that indicate whether the Refresh Rect or Suppress Output
PDUs are supported by the server.
Therefore in rdp_read_general_capability_set() we must only
change the respective settings if we are not in server mode.
