core: add bpf-foreign cgroup mask and harness

Add CGROUP_MASK_BPF_FOREIGN to CGROUP_MASK_BPF and standard cgroup
context harness.

src/basic/cgroup-util.c

@@ -2163,6 +2163,7 @@ static const char *const cgroup_controller_table[_CGROUP_CONTROLLER_MAX] = {
         [CGROUP_CONTROLLER_PIDS] = "pids",
         [CGROUP_CONTROLLER_BPF_FIREWALL] = "bpf-firewall",
         [CGROUP_CONTROLLER_BPF_DEVICES] = "bpf-devices",
+        [CGROUP_CONTROLLER_BPF_FOREIGN] = "bpf-foreign",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(cgroup_controller, CGroupController);

src/basic/cgroup-util.h

@@ -30,6 +30,7 @@ typedef enum CGroupController {
         /* BPF-based pseudo-controllers, v2 only */
         CGROUP_CONTROLLER_BPF_FIREWALL,
         CGROUP_CONTROLLER_BPF_DEVICES,
+        CGROUP_CONTROLLER_BPF_FOREIGN,
 
         _CGROUP_CONTROLLER_MAX,
         _CGROUP_CONTROLLER_INVALID = -EINVAL,
@@ -49,6 +50,7 @@ typedef enum CGroupMask {
         CGROUP_MASK_PIDS = CGROUP_CONTROLLER_TO_MASK(CGROUP_CONTROLLER_PIDS),
         CGROUP_MASK_BPF_FIREWALL = CGROUP_CONTROLLER_TO_MASK(CGROUP_CONTROLLER_BPF_FIREWALL),
         CGROUP_MASK_BPF_DEVICES = CGROUP_CONTROLLER_TO_MASK(CGROUP_CONTROLLER_BPF_DEVICES),
+        CGROUP_MASK_BPF_FOREIGN = CGROUP_CONTROLLER_TO_MASK(CGROUP_CONTROLLER_BPF_FOREIGN),
 
         /* All real cgroup v1 controllers */
         CGROUP_MASK_V1 = CGROUP_MASK_CPU|CGROUP_MASK_CPUACCT|CGROUP_MASK_BLKIO|CGROUP_MASK_MEMORY|CGROUP_MASK_DEVICES|CGROUP_MASK_PIDS,
@@ -57,7 +59,7 @@ typedef enum CGroupMask {
         CGROUP_MASK_V2 = CGROUP_MASK_CPU|CGROUP_MASK_CPUSET|CGROUP_MASK_IO|CGROUP_MASK_MEMORY|CGROUP_MASK_PIDS,
 
         /* All cgroup v2 BPF pseudo-controllers */
-        CGROUP_MASK_BPF = CGROUP_MASK_BPF_FIREWALL|CGROUP_MASK_BPF_DEVICES,
+        CGROUP_MASK_BPF = CGROUP_MASK_BPF_FIREWALL|CGROUP_MASK_BPF_DEVICES|CGROUP_MASK_BPF_FOREIGN,
 
         _CGROUP_MASK_ALL = CGROUP_CONTROLLER_TO_MASK(_CGROUP_CONTROLLER_MAX) - 1
 } CGroupMask;