forked from Minki/linux
14dc6f04f4
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>
103 lines
2.4 KiB
C
103 lines
2.4 KiB
C
/* Copyright (c) 2017 Facebook
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*/
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#include <linux/slab.h>
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#include <linux/bpf.h>
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#include "map_in_map.h"
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struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
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{
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struct bpf_map *inner_map, *inner_map_meta;
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struct fd f;
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f = fdget(inner_map_ufd);
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inner_map = __bpf_map_get(f);
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if (IS_ERR(inner_map))
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return inner_map;
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/* prog_array->owner_prog_type and owner_jited
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* is a runtime binding. Doing static check alone
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* in the verifier is not enough.
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*/
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if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY) {
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fdput(f);
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return ERR_PTR(-ENOTSUPP);
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}
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/* Does not support >1 level map-in-map */
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if (inner_map->inner_map_meta) {
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fdput(f);
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return ERR_PTR(-EINVAL);
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}
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inner_map_meta = kzalloc(sizeof(*inner_map_meta), GFP_USER);
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if (!inner_map_meta) {
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fdput(f);
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return ERR_PTR(-ENOMEM);
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}
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inner_map_meta->map_type = inner_map->map_type;
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inner_map_meta->key_size = inner_map->key_size;
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inner_map_meta->value_size = inner_map->value_size;
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inner_map_meta->map_flags = inner_map->map_flags;
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inner_map_meta->ops = inner_map->ops;
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inner_map_meta->max_entries = inner_map->max_entries;
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fdput(f);
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return inner_map_meta;
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}
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void bpf_map_meta_free(struct bpf_map *map_meta)
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{
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kfree(map_meta);
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}
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bool bpf_map_meta_equal(const struct bpf_map *meta0,
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const struct bpf_map *meta1)
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{
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/* No need to compare ops because it is covered by map_type */
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return meta0->map_type == meta1->map_type &&
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meta0->key_size == meta1->key_size &&
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meta0->value_size == meta1->value_size &&
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meta0->map_flags == meta1->map_flags &&
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meta0->max_entries == meta1->max_entries;
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}
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void *bpf_map_fd_get_ptr(struct bpf_map *map,
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struct file *map_file /* not used */,
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int ufd)
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{
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struct bpf_map *inner_map;
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struct fd f;
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f = fdget(ufd);
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inner_map = __bpf_map_get(f);
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if (IS_ERR(inner_map))
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return inner_map;
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if (bpf_map_meta_equal(map->inner_map_meta, inner_map))
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inner_map = bpf_map_inc(inner_map, false);
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else
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inner_map = ERR_PTR(-EINVAL);
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fdput(f);
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return inner_map;
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}
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void bpf_map_fd_put_ptr(void *ptr)
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{
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/* ptr->ops->map_free() has to go through one
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* rcu grace period by itself.
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*/
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bpf_map_put(ptr);
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}
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u32 bpf_map_fd_sys_lookup_elem(void *ptr)
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{
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return ((struct bpf_map *)ptr)->id;
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}
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