- Adds 3 new "pseudo-random" filter expressions:
* random8 (8bit)
* random16 (16bit)
* random32 (32bit)
Not really "random", but these values are based
on a hash of the packet headers & timestamp.
These are useful for traffic sampling, e.g.:
"random8 < 100" matches ~39% of all packets.
- Add new WinDivertHelperHashPacket() helper
function. The algorithm is an xxHash variant.
This function allows the user application to
"shutdown" a handle in anticipation of a
call to WinDivertClose(). When a handle has
been shutdown, new packets will no longer be
queued. However, existing queued packets can
still be read by WinDivertRecv(). When the
queue is emptied, WinDivertRecv() will fail
with ERROR_NO_DATA.
The WinDivertShutdown() function is analogous
to the shutdown() socket function.
This change also simplifies events.
Adds the follow terms to the filter language:
- packet[idx]: 8bit packet value at idx.
- packet16[idx]: 16bit packet value at idx.
- packet32[idx]: 32bit packet value at idx.
- PROTO.Payload[idx]: 8bit payload value at idx.
- PROTO.Payload16[idx]: 16bit payload value at
idx.
- PROTO.Payload32[idx]: 32bit payload value at
idx.
where PROTO is {tcp,udp}.
16 and 32bit values assume network byte ordering.
The index may be:
- An undecorated integer, in which case the
packet or payload is treated as a 8/16/32bit
value array, similar to C arrays.
- A 'b' decorated integer, (e.g, packet32[17b]),
in which case the integer is interpreted as a
byte offset.
- A negative (un)decorated integer, in which
case indexing begins at the *end* of the
packet or payload. E.g., packet32[-1] is the
last 32bits of the packet.
If the index is out-of-bounds, then the test
is deemed to be equivalent to "false".
This change allows multiple packets to be
received/sent at once, reducing overheads. To
exploit this feature, applications need to use
the WinDivertRecvEx()/WinDivertSendEx()
functions with the new addrLen parameter. The
passthru example has been modified to use
batching.
The DEBUG flag has been retired since it
conflicts with batching, and was not very
useful anyway.
Adds a new SOCKET layer for monitoring socket
events, such as BIND, LISTEN, CONNECT,
and ACCEPT. These events occur before the
flow is established (and unlike the FLOW layer)
it is possible to block/drop SOCKET events.
Otherwise, this layer is very similar to the
FLOW layer, so the PID is available and injection
is not possible. This commit should be
considered to be a WIP.
Other changes:
- New socketdump.exe sample. Prints socket
events.
- Improve IPv6 address parsing.
- New helper functions:
* WinDivertHelperFormatIPv4Address
* WinDivertHelperFormatIPv6Address
- Fix REFLECT bugs.
- The network 5-tuple can now be accessed at
the NETWORK layer.
- Various cleanups.
Adds a new REFLECT layer for monitoring WinDivert
handles. This includes:
- three new REFLECT events: ESTABLISHED, OPEN and
CLOSE;
- modifying the ADDRESS for REFLECT data:
open time, process-id, layer, flags, and
priority of the opened handle; and
- allowing WinDivertRecv() to read a
representation of the opened filter.
This change also includes a new "object"
representation for WinDivert filter strings.
The API has been updated as follows:
- WinDivertHelperCompileFilter (replaces
CheckFilter) compiles filter strings into the
object form; and
- WinDivertHelperFormatFilter can "decompile" an
object back into a human-readable filter
string.
Other:
- New NO_INSTALL flag.
- New windivertctl.exe sample program.
Since pseudo checksums can now be arbitrary
values, the WinDivertHelperCalcChecksums function
no longer attempts to calculate the pseudo-
header checksum.
The MSVCRT*.dll dependency has been removed by:
(1) using Win32 API equivalents where possible,
and (2) re-implementing some basic C runtime
functions. This prevents multiple MSVCRTs from
being loaded at runtime (if the application uses
a different version than the DLL). The new
WinDivert.dll only depends on KERNEL32.dll and
ADVAPI32.dll.
Furthermore, the MINGW build has been extended
to generate a WinDivert.lib import library file.
This means that the MINGW DLL can now be used
directly by Visual Studio (any version).
For some reason pseudo checksums do not work on
some systems. The workaround is to modify
WinDivertSend() so that it calculates the full
checksums before forwarding the packet to the
driver.
This allows projects that are strictly "GPLv2
only" to use WinDivert without licensing issues.
See the FSF's compatibility matrix here:
https://www.gnu.org/licenses/gpl-faq.en.html
This change does not affect existing projects
that can continue to use the LGPLv3 as before.
Also, bump the WinDivert version to 1.4.1.
WinDivert will now mark any packet injected by
another driver as an "impostor", meaning that it
did not originate from the network. Changes are:
- User programs may filter impostor packets.
- WinDivertSend() automatically decrements the TTL
for imposter packets, see #41.
Most NIC cards support checksum offloading,
meaning that it is not necessary to calculate the
full IP/TCP/UDP checksums for injected packets.
WINDIVERT_ADDRESS has been extended to include 3
extra flags that indicate if the packet has full
or pseudo checksums. This is a WIP.
The WINDIVERT_HELPER_NO_REPLACE flag tells WinDivertHelperCalcChecksums not to
recalculate and replace non-zero checksum fields. This is useful for
reconstructing the checksums for packets returned by WinDivertRecv(), where
all non-zero checksum fields are already valid. This allows WinDivert1.2
to achieve similar efficiency as WinDivert1.1, where checksums were calculated
by the driver.
Note that for modified packets, the WINDIVERT_HELPER_NO_REPLACE flag should
not be used, as all checksums need to be recalculated from scratch anyway.
- As discussed in #37, the WINDIVERT_FLAG_NO_CHECKSUM behavior has become the
default. This means that outbound packets returned by WinDivertRecv() are
no longer guaranteed to have valid checksums, thanks to TCP checksum
offloading by the Windows TCP/IP stack. The checksums can still be
recovered by calling WinDivertHelperCalcChecksums() manually.
- Remove the old WinDivert1.0 legacy API, as nobody should still be using it.
Replaces the old filter compiler with a new version that:
- Is a cleaner, more extensible, implementation.
- Can report specific error messages (e.g. bad token vs parse error).
- Supports the new C-style if-then-else expression "(A? B: C)" syntax.
Two new WinDivert helper API functions have been implemented:
- WinDivertHelperCheckFilter() can be used to check a filter string for
errors.
- WinDivertHelperEvalFilter() evaluates a filter on a given packet. Will be
useful for testing.
* WinDivert sublayers are created and inserted when the driver is loaded.
* All WinDivert callouts are installed at the same sublayer.
- Clean-up the implementation of priorities.
- Re-introduce deep copying for SNIFF mode. This avoids referencing the
sniffed packets.
- Fix-up the netfilter example:
* Don't send RSTs to RST/FINs, this can start a RST war.
* Don't inject ICMP outbound - this may not be a problem despite 1233 errors.
1) Remove the dependency on the WdfCoInstaller*.dll file. This file appears
to be unnecessary for Windows 7 and up, and for patched Vista+2008.
2) Remove the WinDivert.inf file (only used by the co-installer).
3) 32/64-bit versions of the driver are now explicitly named, meaning that
the two can co-exist in the same directory.
4) The 32-bit WinDivert.dll can now automatically load the 64-bit driver on
64-bit Windows. This means it is possible to write 32-bit WinDivert
applications that automatically work on 64-bit windows.
5) WinDivert.dll now schedules the WinDivert service to be deleted right
away. This should fix some cases where the service is never deleted,
even during reboot.
6) Updated build scripts to reflect the changes.
* Re-brand "DIVERT" to "WINDIVERT" throughout the code-base.
* New flags:
> WINDIVERT_FLAG_PASSTHRU: Do not drop nor capture packets. Useful
for injection-only handles.
> WINDIVERT_FLAG_NO_CHECKSUM: Do not guarantee that diverted packets
have a correct checksum.
NOTE: Not yet tested!
* New default values and limits for various WinDivert parameters,
including WINDIVERT_PARAM_QUEUE_LEN, WINDIVERT_PARAM_QUEUE_TIME, and
the maximum filter length.
* New extended WinDivert functions that support asynchronous I/O:
> WinDivertRecvEx(..)
> WinDivertSendEx(..)
NOTE: Not yet tested!
* The WinDivert driver now services reads (receives) out-of-band.
The motivation is because WFP callouts are run at DISPATCH_LEVEL, so
we should not be doing expensive work in the ClassifyFn. This is also
the same reason why the filter length has been restricted.
basil00