Commit 1f427a80 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'bpf_link-observability' 



Andrii Nakryiko says:

====================
This patch series adds various observability APIs to bpf_link:
  - each bpf_link now gets ID, similar to bpf_map and bpf_prog, by which
    user-space can iterate over all existing bpf_links and create limited FD
    from ID;
  - allows to get extra object information with bpf_link general and
    type-specific information;
  - implements `bpf link show` command which lists all active bpf_links in the
    system;
  - implements `bpf link pin` allowing to pin bpf_link by ID or from other
    pinned path.

v2->v3:
  - improve spin locking around bpf_link ID (Alexei);
  - simplify bpf_link_info handling and fix compilation error on sh arch;
v1->v2:
  - simplified `bpftool link show` implementation (Quentin);
  - fixed formatting of bpftool-link.rst (Quentin);
  - fixed attach type printing logic (Quentin);
rfc->v1:
  - dropped read-only bpf_links (Alexei);
  - fixed bug in bpf_link_cleanup() not removing ID;
  - fixed bpftool link pinning search logic;
  - added bash-completion and man page.
====================

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 9b329d0d 5d085ad2

include/linux/bpf-cgroup.h

+0 −14
Original line number Diff line number Diff line
@@ -57,8 +57,6 @@ struct bpf_cgroup_link { 
	enum bpf_attach_type type;

};



extern const struct bpf_link_ops bpf_cgroup_link_lops;



struct bpf_prog_list {

	struct list_head node;

	struct bpf_prog *prog;
@@ -100,8 +98,6 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, 
int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,

			struct bpf_cgroup_link *link,

			enum bpf_attach_type type);

int __cgroup_bpf_replace(struct cgroup *cgrp, struct bpf_cgroup_link *link,

			 struct bpf_prog *new_prog);

int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,

		       union bpf_attr __user *uattr);
@@ -112,8 +108,6 @@ int cgroup_bpf_attach(struct cgroup *cgrp, 
		      u32 flags);

int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,

		      enum bpf_attach_type type);

int cgroup_bpf_replace(struct bpf_link *link, struct bpf_prog *old_prog,

		       struct bpf_prog *new_prog);

int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,

		     union bpf_attr __user *uattr);
@@ -353,7 +347,6 @@ int cgroup_bpf_prog_query(const union bpf_attr *attr, 
#else



struct bpf_prog;

struct bpf_link;

struct cgroup_bpf {};

static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; }

static inline void cgroup_bpf_offline(struct cgroup *cgrp) {}
@@ -377,13 +370,6 @@ static inline int cgroup_bpf_link_attach(const union bpf_attr *attr, 
	return -EINVAL;

}



static inline int cgroup_bpf_replace(struct bpf_link *link,

				     struct bpf_prog *old_prog,

				     struct bpf_prog *new_prog)

{

	return -EINVAL;

}



static inline int cgroup_bpf_prog_query(const union bpf_attr *attr,

					union bpf_attr __user *uattr)

{

include/linux/bpf.h

+21 −5
Original line number Diff line number Diff line
@@ -1026,9 +1026,11 @@ extern const struct file_operations bpf_prog_fops; 
	extern const struct bpf_verifier_ops _name ## _verifier_ops;

#define BPF_MAP_TYPE(_id, _ops) \

	extern const struct bpf_map_ops _ops;

#define BPF_LINK_TYPE(_id, _name)

#include <linux/bpf_types.h>

#undef BPF_PROG_TYPE

#undef BPF_MAP_TYPE

#undef BPF_LINK_TYPE



extern const struct bpf_prog_ops bpf_offload_prog_ops;

extern const struct bpf_verifier_ops tc_cls_act_analyzer_ops;
@@ -1085,21 +1087,35 @@ int bpf_prog_new_fd(struct bpf_prog *prog); 


struct bpf_link {

	atomic64_t refcnt;

	u32 id;

	enum bpf_link_type type;

	const struct bpf_link_ops *ops;

	struct bpf_prog *prog;

	struct work_struct work;

};



struct bpf_link_primer {

	struct bpf_link *link;

	struct file *file;

	int fd;

	u32 id;

};



struct bpf_link_ops {

	void (*release)(struct bpf_link *link);

	void (*dealloc)(struct bpf_link *link);



	int (*update_prog)(struct bpf_link *link, struct bpf_prog *new_prog,

			   struct bpf_prog *old_prog);

	void (*show_fdinfo)(const struct bpf_link *link, struct seq_file *seq);

	int (*fill_link_info)(const struct bpf_link *link,

			      struct bpf_link_info *info);

};



void bpf_link_init(struct bpf_link *link, const struct bpf_link_ops *ops,

		   struct bpf_prog *prog);

void bpf_link_cleanup(struct bpf_link *link, struct file *link_file,

		      int link_fd);

void bpf_link_init(struct bpf_link *link, enum bpf_link_type type,

		   const struct bpf_link_ops *ops, struct bpf_prog *prog);

int bpf_link_prime(struct bpf_link *link, struct bpf_link_primer *primer);

int bpf_link_settle(struct bpf_link_primer *primer);

void bpf_link_cleanup(struct bpf_link_primer *primer);

void bpf_link_inc(struct bpf_link *link);

void bpf_link_put(struct bpf_link *link);

int bpf_link_new_fd(struct bpf_link *link);

include/linux/bpf_types.h

+6 −0
Original line number Diff line number Diff line
@@ -118,3 +118,9 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) 
#if defined(CONFIG_BPF_JIT)

BPF_MAP_TYPE(BPF_MAP_TYPE_STRUCT_OPS, bpf_struct_ops_map_ops)

#endif



BPF_LINK_TYPE(BPF_LINK_TYPE_RAW_TRACEPOINT, raw_tracepoint)

BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing)

#ifdef CONFIG_CGROUP_BPF

BPF_LINK_TYPE(BPF_LINK_TYPE_CGROUP, cgroup)

#endif

include/uapi/linux/bpf.h

+31 −0
Original line number Diff line number Diff line
@@ -113,6 +113,8 @@ enum bpf_cmd { 
	BPF_MAP_DELETE_BATCH,

	BPF_LINK_CREATE,

	BPF_LINK_UPDATE,

	BPF_LINK_GET_FD_BY_ID,

	BPF_LINK_GET_NEXT_ID,

};



enum bpf_map_type {
@@ -220,6 +222,15 @@ enum bpf_attach_type { 


#define MAX_BPF_ATTACH_TYPE __MAX_BPF_ATTACH_TYPE



enum bpf_link_type {

	BPF_LINK_TYPE_UNSPEC = 0,

	BPF_LINK_TYPE_RAW_TRACEPOINT = 1,

	BPF_LINK_TYPE_TRACING = 2,

	BPF_LINK_TYPE_CGROUP = 3,



	MAX_BPF_LINK_TYPE,

};



/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command

 *

 * NONE(default): No further bpf programs allowed in the subtree.
@@ -523,6 +534,7 @@ union bpf_attr { 
			__u32		prog_id;

			__u32		map_id;

			__u32		btf_id;

			__u32		link_id;

		};

		__u32		next_id;

		__u32		open_flags;
@@ -3609,6 +3621,25 @@ struct bpf_btf_info { 
	__u32 id;

} __attribute__((aligned(8)));



struct bpf_link_info {

	__u32 type;

	__u32 id;

	__u32 prog_id;

	union {

		struct {

			__aligned_u64 tp_name; /* in/out: tp_name buffer ptr */

			__u32 tp_name_len;     /* in/out: tp_name buffer len */

		} raw_tracepoint;

		struct {

			__u32 attach_type;

		} tracing;

		struct {

			__u64 cgroup_id;

			__u32 attach_type;

		} cgroup;

	};

} __attribute__((aligned(8)));



/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed

 * by user and intended to be used by socket (e.g. to bind to, depends on

 * attach attach type).

kernel/bpf/btf.c

+2 −0
Original line number Diff line number Diff line
@@ -3482,6 +3482,7 @@ extern char __weak __stop_BTF[]; 
extern struct btf *btf_vmlinux;



#define BPF_MAP_TYPE(_id, _ops)

#define BPF_LINK_TYPE(_id, _name)

static union {

	struct bpf_ctx_convert {

#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
@@ -3508,6 +3509,7 @@ static u8 bpf_ctx_convert_map[] = { 
	0, /* avoid empty array */

};

#undef BPF_MAP_TYPE

#undef BPF_LINK_TYPE



static const struct btf_member *

btf_get_prog_ctx_type(struct bpf_verifier_log *log, struct btf *btf,

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