linux/kernel/bpf/map_in_map.h

/* Copyright (c) 2017 Facebook
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 */
#ifndef __MAP_IN_MAP_H__
#define __MAP_IN_MAP_H__

#include <linux/types.h>

struct file;
struct bpf_map;

struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd);
void bpf_map_meta_free(struct bpf_map *map_meta);
bool bpf_map_meta_equal(const struct bpf_map *meta0,
			const struct bpf_map *meta1);
void *bpf_map_fd_get_ptr(struct bpf_map *map, struct file *map_file,
			 int ufd);
void bpf_map_fd_put_ptr(void *ptr);
u32 bpf_map_fd_sys_lookup_elem(void *ptr);

#endif
bpf: Add array of maps support This patch adds a few helper funcs to enable map-in-map support (i.e. outer_map->inner_map). The first outer_map type BPF_MAP_TYPE_ARRAY_OF_MAPS is also added in this patch. The next patch will introduce a hash of maps type. Any bpf map type can be acted as an inner_map. The exception is BPF_MAP_TYPE_PROG_ARRAY because the extra level of indirection makes it harder to verify the owner_prog_type and owner_jited. Multi-level map-in-map is not supported (i.e. map->map is ok but not map->map->map). When adding an inner_map to an outer_map, it currently checks the map_type, key_size, value_size, map_flags, max_entries and ops. The verifier also uses those map's properties to do static analysis. map_flags is needed because we need to ensure BPF_PROG_TYPE_PERF_EVENT is using a preallocated hashtab for the inner_hash also. ops and max_entries are needed to generate inlined map-lookup instructions. For simplicity reason, a simple '==' test is used for both map_flags and max_entries. The equality of ops is implied by the equality of map_type. During outer_map creation time, an inner_map_fd is needed to create an outer_map. However, the inner_map_fd's life time does not depend on the outer_map. The inner_map_fd is merely used to initialize the inner_map_meta of the outer_map. Also, for the outer_map: * It allows element update and delete from syscall * It allows element lookup from bpf_prog The above is similar to the current fd_array pattern. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net> 2017-03-22 20:00:33 +03:00			`/* Copyright (c) 2017 Facebook`
			`*`
			`* This program is free software; you can redistribute it and/or`
			`* modify it under the terms of version 2 of the GNU General Public`
			`* License as published by the Free Software Foundation.`
			`*/`
			`#ifndef __MAP_IN_MAP_H__`
			`#define __MAP_IN_MAP_H__`

			`#include <linux/types.h>`

			`struct file;`
			`struct bpf_map;`

			`struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd);`
			`void bpf_map_meta_free(struct bpf_map *map_meta);`
			`bool bpf_map_meta_equal(const struct bpf_map *meta0,`
			`const struct bpf_map *meta1);`
			`void bpf_map_fd_get_ptr(struct bpf_map map, struct file *map_file,`
			`int ufd);`
			`void bpf_map_fd_put_ptr(void *ptr);`
bpf: Add syscall lookup support for fd array and htab This patch allows userspace to do BPF_MAP_LOOKUP_ELEM on BPF_MAP_TYPE_PROG_ARRAY, BPF_MAP_TYPE_ARRAY_OF_MAPS and BPF_MAP_TYPE_HASH_OF_MAPS. The lookup returns a prog-id or map-id to the userspace. The userspace can then use the BPF_PROG_GET_FD_BY_ID or BPF_MAP_GET_FD_BY_ID to get a fd. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net> 2017-06-28 09:08:34 +03:00			`u32 bpf_map_fd_sys_lookup_elem(void *ptr);`
bpf: Add array of maps support This patch adds a few helper funcs to enable map-in-map support (i.e. outer_map->inner_map). The first outer_map type BPF_MAP_TYPE_ARRAY_OF_MAPS is also added in this patch. The next patch will introduce a hash of maps type. Any bpf map type can be acted as an inner_map. The exception is BPF_MAP_TYPE_PROG_ARRAY because the extra level of indirection makes it harder to verify the owner_prog_type and owner_jited. Multi-level map-in-map is not supported (i.e. map->map is ok but not map->map->map). When adding an inner_map to an outer_map, it currently checks the map_type, key_size, value_size, map_flags, max_entries and ops. The verifier also uses those map's properties to do static analysis. map_flags is needed because we need to ensure BPF_PROG_TYPE_PERF_EVENT is using a preallocated hashtab for the inner_hash also. ops and max_entries are needed to generate inlined map-lookup instructions. For simplicity reason, a simple '==' test is used for both map_flags and max_entries. The equality of ops is implied by the equality of map_type. During outer_map creation time, an inner_map_fd is needed to create an outer_map. However, the inner_map_fd's life time does not depend on the outer_map. The inner_map_fd is merely used to initialize the inner_map_meta of the outer_map. Also, for the outer_map: * It allows element update and delete from syscall * It allows element lookup from bpf_prog The above is similar to the current fd_array pattern. Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net> 2017-03-22 20:00:33 +03:00
			`#endif`