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.
WinDivert now treats all offloaded checksum fields as zero:
- WinDivertRecv() will zero all offloaded checksum fields.
- Filter matching will treat offloaded fields as zero.
Bump version and change magic numbers to make the driver incompatible with
older versions. Also cleanup some driver checksum code missed by previous
commit.
- 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.
by the classify function and silently dropped. This can degrade outbound
speed significantly, as it forces the Windows TCP/IP stack to re-send the
missing data. Thanks to GhalemB who found the bug & fix.
* 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.
basil00