bpf: introduce cgroup storage maps
This commit introduces BPF_MAP_TYPE_CGROUP_STORAGE maps:
a special type of maps which are implementing the cgroup storage.
>From the userspace point of view it's almost a generic
hash map with the (cgroup inode id, attachment type) pair
used as a key.
The only difference is that some operations are restricted:
1) a user can't create new entries,
2) a user can't remove existing entries.
The lookup from userspace is o(log(n)).
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index d50c2f0..7d00d58 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -4,19 +4,39 @@
#include <linux/errno.h>
#include <linux/jump_label.h>
+#include <linux/rbtree.h>
#include <uapi/linux/bpf.h>
struct sock;
struct sockaddr;
struct cgroup;
struct sk_buff;
+struct bpf_map;
+struct bpf_prog;
struct bpf_sock_ops_kern;
+struct bpf_cgroup_storage;
#ifdef CONFIG_CGROUP_BPF
extern struct static_key_false cgroup_bpf_enabled_key;
#define cgroup_bpf_enabled static_branch_unlikely(&cgroup_bpf_enabled_key)
+struct bpf_cgroup_storage_map;
+
+struct bpf_storage_buffer {
+ struct rcu_head rcu;
+ char data[0];
+};
+
+struct bpf_cgroup_storage {
+ struct bpf_storage_buffer *buf;
+ struct bpf_cgroup_storage_map *map;
+ struct bpf_cgroup_storage_key key;
+ struct list_head list;
+ struct rb_node node;
+ struct rcu_head rcu;
+};
+
struct bpf_prog_list {
struct list_head node;
struct bpf_prog *prog;
@@ -77,6 +97,15 @@
int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
short access, enum bpf_attach_type type);
+struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog);
+void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage);
+void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
+ struct cgroup *cgroup,
+ enum bpf_attach_type type);
+void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage);
+int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *map);
+void bpf_cgroup_storage_release(struct bpf_prog *prog, struct bpf_map *map);
+
/* Wrappers for __cgroup_bpf_run_filter_skb() guarded by cgroup_bpf_enabled. */
#define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk, skb) \
({ \
@@ -221,6 +250,15 @@
return -EINVAL;
}
+static inline int bpf_cgroup_storage_assign(struct bpf_prog *prog,
+ struct bpf_map *map) { return 0; }
+static inline void bpf_cgroup_storage_release(struct bpf_prog *prog,
+ struct bpf_map *map) {}
+static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(
+ struct bpf_prog *prog) { return 0; }
+static inline void bpf_cgroup_storage_free(
+ struct bpf_cgroup_storage *storage) {}
+
#define cgroup_bpf_enabled (0)
#define BPF_CGROUP_PRE_CONNECT_ENABLED(sk) (0)
#define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk,skb) ({ 0; })