datapath: Fix uninitializaed variable with GRE GSO.

If a packet is neither GSO nor CHECKSUM_PARTIAL then the
GRE GSO compatibility code can use an uninitialized IP ID.

CC: Pravin Shelar <pshelar@nicira.com>
Reported-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Jesse Gross <jesse@nicira.com>
datapath: Fix a kernel crash caused by corrupted mask list.

When flow table is copied, the mask list from the old table
is not properly copied into the new table. The corrupted mask
list in the new table will lead to kernel crash. This patch
fixes this bug.

Bug #18110
Reported-by: Justin Pettit <jpettit@nicira.com>
Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
datapath: Add GSO/Tunnel links to gitignore

Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Jesse Gross <jesse@nicira.com>
ofpacts_check: Remove unnecessary flow copying.

Signed-off-by: Jarno Rajahalme <jarno.rajahalme@nsn.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
acinclude: Improve detection of not-understood compiler options with clang.

By default, clang warns about but does not fail on unknown -W options.
This made configure add the option to WARNING_FLAGS, which caused the
warning about not-understood warnings to be emitted for every file
compiled.

In combination with -Werror, clang does fail on unknown -W options.  This
commit adds -Werror during configure's warning tests, which should cause
the not-understood warnings to be detected that way.

Reported-by: Ed Maste <emaste@freebsd.org>
Tested-by: Ed Maste <emaste@freebsd.org>
Signed-off-by: Ben Pfaff <blp@nicira.com>