On 7/8/20 1:43 AM, Stanislav Fomichev wrote:
On Tue, Jul 7, 2020 at 2:42 PM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
On 7/7/20 1:42 AM, Andrii Nakryiko wrote:
On Mon, Jul 6, 2020 at 4:02 PM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
Implement BPF_CGROUP_INET_SOCK_RELEASE hook that triggers
on inet socket release. It triggers only for userspace
sockets, the same semantics as existing BPF_CGROUP_INET_SOCK_CREATE.
The only questionable part here is the sock->sk check
in the inet_release. Looking at the places where we
do 'sock->sk = NULL', I don't understand how it can race
with inet_release and why the check is there (it's been
there since the initial git import). Otherwise, the
change itself is pretty simple, we add a BPF hook
to the inet_release and avoid calling it for kernel
sockets.
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
---
include/linux/bpf-cgroup.h | 4 ++++
include/uapi/linux/bpf.h | 1 +
kernel/bpf/syscall.c | 3 +++
net/core/filter.c | 1 +
net/ipv4/af_inet.c | 3 +++
5 files changed, 12 insertions(+)
Looks good overall, but I have no idea about sock->sk NULL case.
+1, looks good & very useful hook. For the sock->sk NULL case here's a related
discussion on why it's needed [0].
Thanks for the pointer! I'll resend a v5 with s/sock/sock_create/ you
mentioned and will clean up the commit description a bit.
Already fixed up the selftest and a typo in the commit desc there & applied it. Let
me know if you prefer a respin though and I can toss it taking the respin which would
work just as well. :)
Thanks,
Daniel
