Commit ad8edd0d authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'link_query-bpf_iter' 



Yonghong Song says:

====================
"link" has been an important concept for bpf ecosystem to connect
bpf program with other properties. Currently, the information related
information can be queried from userspace through bpf command
BPF_LINK_GET_NEXT_ID, BPF_LINK_GET_FD_BY_ID and BPF_OBJ_GET_INFO_BY_FD.
The information is also available by "cating" /proc/<pid>/fdinfo/<link_fd>.
Raw_tracepoint, tracing, cgroup, netns and xdp links are already
supported in the kernel and bpftool.

This patch added support for bpf iterator. Patch #1 added generic support
for link querying interface. Patch #2 implemented callback functions
for map element bpf iterators. Patch #3 added bpftool support.

Changelogs:
  v3 -> v4:
    . return target specific link_info even if target_name buffer
      is empty. (Andrii)
  v2 -> v3:
    . remove extra '\t' when fdinfo prints map_id to make parsing
      consistent. (Andrii)
  v1 -> v2:
    . fix checkpatch.pl warnings. (Jakub)
====================

Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 149cb339 e60495ea

include/linux/bpf.h

+10 −0
Original line number Diff line number Diff line
@@ -1218,12 +1218,18 @@ typedef int (*bpf_iter_attach_target_t)(struct bpf_prog *prog, 
					union bpf_iter_link_info *linfo,

					struct bpf_iter_aux_info *aux);

typedef void (*bpf_iter_detach_target_t)(struct bpf_iter_aux_info *aux);

typedef void (*bpf_iter_show_fdinfo_t) (const struct bpf_iter_aux_info *aux,

					struct seq_file *seq);

typedef int (*bpf_iter_fill_link_info_t)(const struct bpf_iter_aux_info *aux,

					 struct bpf_link_info *info);



#define BPF_ITER_CTX_ARG_MAX 2

struct bpf_iter_reg {

	const char *target;

	bpf_iter_attach_target_t attach_target;

	bpf_iter_detach_target_t detach_target;

	bpf_iter_show_fdinfo_t show_fdinfo;

	bpf_iter_fill_link_info_t fill_link_info;

	u32 ctx_arg_info_size;

	struct bpf_ctx_arg_aux ctx_arg_info[BPF_ITER_CTX_ARG_MAX];

	const struct bpf_iter_seq_info *seq_info;
@@ -1250,6 +1256,10 @@ int bpf_iter_new_fd(struct bpf_link *link); 
bool bpf_link_is_iter(struct bpf_link *link);

struct bpf_prog *bpf_iter_get_info(struct bpf_iter_meta *meta, bool in_stop);

int bpf_iter_run_prog(struct bpf_prog *prog, void *ctx);

void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,

			      struct seq_file *seq);

int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,

				struct bpf_link_info *info);



int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value);

int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value);

include/uapi/linux/bpf.h

+7 −0
Original line number Diff line number Diff line
@@ -4071,6 +4071,13 @@ struct bpf_link_info { 
			__u64 cgroup_id;

			__u32 attach_type;

		} cgroup;

		struct {

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

			__u32 target_name_len;	   /* in/out: target_name buffer len */

			union {

				__u32 map_id;

			} map;

		} iter;

		struct  {

			__u32 netns_ino;

			__u32 attach_type;

kernel/bpf/bpf_iter.c

+58 −0
Original line number Diff line number Diff line
@@ -377,10 +377,68 @@ out_unlock: 
	return ret;

}



static void bpf_iter_link_show_fdinfo(const struct bpf_link *link,

				      struct seq_file *seq)

{

	struct bpf_iter_link *iter_link =

		container_of(link, struct bpf_iter_link, link);

	bpf_iter_show_fdinfo_t show_fdinfo;



	seq_printf(seq,

		   "target_name:\t%s\n",

		   iter_link->tinfo->reg_info->target);



	show_fdinfo = iter_link->tinfo->reg_info->show_fdinfo;

	if (show_fdinfo)

		show_fdinfo(&iter_link->aux, seq);

}



static int bpf_iter_link_fill_link_info(const struct bpf_link *link,

					struct bpf_link_info *info)

{

	struct bpf_iter_link *iter_link =

		container_of(link, struct bpf_iter_link, link);

	char __user *ubuf = u64_to_user_ptr(info->iter.target_name);

	bpf_iter_fill_link_info_t fill_link_info;

	u32 ulen = info->iter.target_name_len;

	const char *target_name;

	u32 target_len;



	if (!ulen ^ !ubuf)

		return -EINVAL;



	target_name = iter_link->tinfo->reg_info->target;

	target_len =  strlen(target_name);

	info->iter.target_name_len = target_len + 1;



	if (ubuf) {

		if (ulen >= target_len + 1) {

			if (copy_to_user(ubuf, target_name, target_len + 1))

				return -EFAULT;

		} else {

			char zero = '\0';



			if (copy_to_user(ubuf, target_name, ulen - 1))

				return -EFAULT;

			if (put_user(zero, ubuf + ulen - 1))

				return -EFAULT;

			return -ENOSPC;

		}

	}



	fill_link_info = iter_link->tinfo->reg_info->fill_link_info;

	if (fill_link_info)

		return fill_link_info(&iter_link->aux, info);



	return 0;

}



static const struct bpf_link_ops bpf_iter_link_lops = {

	.release = bpf_iter_link_release,

	.dealloc = bpf_iter_link_dealloc,

	.update_prog = bpf_iter_link_replace,

	.show_fdinfo = bpf_iter_link_show_fdinfo,

	.fill_link_info = bpf_iter_link_fill_link_info,

};



bool bpf_link_is_iter(struct bpf_link *link)

kernel/bpf/map_iter.c

+15 −0
Original line number Diff line number Diff line
@@ -149,6 +149,19 @@ static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux) 
	bpf_map_put_with_uref(aux->map);

}



void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,

			      struct seq_file *seq)

{

	seq_printf(seq, "map_id:\t%u\n", aux->map->id);

}



int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,

				struct bpf_link_info *info)

{

	info->iter.map.map_id = aux->map->id;

	return 0;

}



DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,

		     struct bpf_map *map, void *key, void *value)
@@ -156,6 +169,8 @@ static const struct bpf_iter_reg bpf_map_elem_reg_info = { 
	.target			= "bpf_map_elem",

	.attach_target		= bpf_iter_attach_map,

	.detach_target		= bpf_iter_detach_map,

	.show_fdinfo		= bpf_iter_map_show_fdinfo,

	.fill_link_info		= bpf_iter_map_fill_link_info,

	.ctx_arg_info_size	= 2,

	.ctx_arg_info		= {

		{ offsetof(struct bpf_iter__bpf_map_elem, key),

net/core/bpf_sk_storage.c

+2 −0
Original line number Diff line number Diff line
@@ -1437,6 +1437,8 @@ static struct bpf_iter_reg bpf_sk_storage_map_reg_info = { 
	.target			= "bpf_sk_storage_map",

	.attach_target		= bpf_iter_attach_map,

	.detach_target		= bpf_iter_detach_map,

	.show_fdinfo		= bpf_iter_map_show_fdinfo,

	.fill_link_info		= bpf_iter_map_fill_link_info,

	.ctx_arg_info_size	= 2,

	.ctx_arg_info		= {

		{ offsetof(struct bpf_iter__bpf_sk_storage_map, sk),

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