cgroup: remove support for NetClass= directive

Support for net_cls.class_id through the NetClass= configuration directive
has been added in v227 in preparation for a per-unit packet filter mechanism.
However, it turns out the kernel people have decided to deprecate the net_cls
and net_prio controllers in v2. Tejun provides a comprehensive justification
for this in his commit, which has landed during the merge window for kernel
v4.5:

  https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=bd1060a1d671

As we're aiming for full support for the v2 cgroup hierarchy, we can no
longer support this feature. Userspace tool such as nftables are moving over
to setting rules that are specific to the full cgroup path of a task, which
obsoletes these controllers anyway.

This commit removes support for tweaking details in the net_cls controller,
but keeps the NetClass= directive around for legacy compatibility reasons.

1 files changed, 0 insertions, 27 deletions

diff --git a/src/core/unit.c b/src/core/unit.c
index ffefae2b94..d39e3dcaeb 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -458,7 +458,6 @@ static void unit_free_requires_mounts_for(Unit *u) {
 static void unit_done(Unit *u) {
         ExecContext *ec;
         CGroupContext *cc;
-        int r;
 
         assert(u);
 
@@ -475,10 +474,6 @@ static void unit_done(Unit *u) {
         cc = unit_get_cgroup_context(u);
         if (cc)
                 cgroup_context_done(cc);
-
-        r = unit_remove_from_netclass_cgroup(u);
-        if (r < 0)
-                log_warning_errno(r, "Unable to remove unit from netclass group: %m");
 }
 
 void unit_free(Unit *u) {
@@ -1263,14 +1258,6 @@ int unit_load(Unit *u) {
                 }
 
                 unit_update_cgroup_members_masks(u);
-
-                /* If we are reloading, we need to wait for the deserializer
-                 * to restore the net_cls ids that have been set previously */
-                if (u->manager->n_reloading <= 0) {
-                        r = unit_add_to_netclass_cgroup(u);
-                        if (r < 0)
-                                return r;
-                }
         }
 
         assert((u->load_state != UNIT_MERGED) == !u->merged_into);
@@ -2601,9 +2588,6 @@ int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
                 unit_serialize_item(u, f, "cgroup", u->cgroup_path);
         unit_serialize_item(u, f, "cgroup-realized", yes_no(u->cgroup_realized));
 
-        if (u->cgroup_netclass_id)
-                unit_serialize_item_format(u, f, "netclass-id", "%" PRIu32, u->cgroup_netclass_id);
-
         if (serialize_jobs) {
                 if (u->job) {
                         fprintf(f, "job\n");
@@ -2841,17 +2825,6 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
                                 u->cgroup_realized = b;
 
                         continue;
-                } else if (streq(l, "netclass-id")) {
-                        r = safe_atou32(v, &u->cgroup_netclass_id);
-                        if (r < 0)
-                                log_unit_debug(u, "Failed to parse netclass ID %s, ignoring.", v);
-                        else {
-                                r = unit_add_to_netclass_cgroup(u);
-                                if (r < 0)
-                                        log_unit_debug_errno(u, r, "Failed to add unit to netclass cgroup, ignoring: %m");
-                        }
-
-                        continue;
                 }
 
                 if (unit_can_serialize(u)) {