On Tue, 24 Mar 2020 19:12:53 +0100 Toke Høiland-Jørgensen wrote: > From: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> > > While it is currently possible for userspace to specify that an existing > XDP program should not be replaced when attaching to an interface, there is > no mechanism to safely replace a specific XDP program with another. > > This patch adds a new netlink attribute, IFLA_XDP_EXPECTED_ID, which can be > set along with IFLA_XDP_FD. If set, the kernel will check that the program > currently loaded on the interface matches the expected one, and fail the > operation if it does not. This corresponds to a 'cmpxchg' memory operation. > Setting the new attribute with a negative value means that no program is > expected to be attached, which corresponds to setting the UPDATE_IF_NOEXIST > flag. > > A new companion flag, XDP_FLAGS_EXPECT_ID, is also added to explicitly > request checking of the EXPECTED_ID attribute. This is needed for userspace > to discover whether the kernel supports the new attribute. > > Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx> Reviewed-by: Jakub Kicinski <kuba@xxxxxxxxxx> Thanks!
