LXR linux/kernel/bpf/map_in

   1/* Copyright (c) 2017 Facebook
   2 *
   3 * This program is free software; you can redistribute it and/or
   4 * modify it under the terms of version 2 of the GNU General Public
   5 * License as published by the Free Software Foundation.
   6 */
   7#include <linux/slab.h>
   8#include <linux/bpf.h>
   9
  10#include "map_in_map.h"
  11
  12struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
  13{
  14        struct bpf_map *inner_map, *inner_map_meta;
  15        struct fd f;
  16
  17        f = fdget(inner_map_ufd);
  18        inner_map = __bpf_map_get(f);
  19        if (IS_ERR(inner_map))
  20                return inner_map;
  21
  22        /* prog_array->owner_prog_type and owner_jited
  23         * is a runtime binding.  Doing static check alone
  24         * in the verifier is not enough.
  25         */
  26        if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY) {
  27                fdput(f);
  28                return ERR_PTR(-ENOTSUPP);
  29        }
  30
  31        /* Does not support >1 level map-in-map */
  32        if (inner_map->inner_map_meta) {
  33                fdput(f);
  34                return ERR_PTR(-EINVAL);
  35        }
  36
  37        inner_map_meta = kzalloc(sizeof(*inner_map_meta), GFP_USER);
  38        if (!inner_map_meta) {
  39                fdput(f);
  40                return ERR_PTR(-ENOMEM);
  41        }
  42
  43        inner_map_meta->map_type = inner_map->map_type;
  44        inner_map_meta->key_size = inner_map->key_size;
  45        inner_map_meta->value_size = inner_map->value_size;
  46        inner_map_meta->map_flags = inner_map->map_flags;
  47        inner_map_meta->ops = inner_map->ops;
  48        inner_map_meta->max_entries = inner_map->max_entries;
  49
  50        fdput(f);
  51        return inner_map_meta;
  52}
  53
  54void bpf_map_meta_free(struct bpf_map *map_meta)
  55{
  56        kfree(map_meta);
  57}
  58
  59bool bpf_map_meta_equal(const struct bpf_map *meta0,
  60                        const struct bpf_map *meta1)
  61{
  62        /* No need to compare ops because it is covered by map_type */
  63        return meta0->map_type == meta1->map_type &&
  64                meta0->key_size == meta1->key_size &&
  65                meta0->value_size == meta1->value_size &&
  66                meta0->map_flags == meta1->map_flags &&
  67                meta0->max_entries == meta1->max_entries;
  68}
  69
  70void *bpf_map_fd_get_ptr(struct bpf_map *map,
  71                         struct file *map_file /* not used */,
  72                         int ufd)
  73{
  74        struct bpf_map *inner_map;
  75        struct fd f;
  76
  77        f = fdget(ufd);
  78        inner_map = __bpf_map_get(f);
  79        if (IS_ERR(inner_map))
  80                return inner_map;
  81
  82        if (bpf_map_meta_equal(map->inner_map_meta, inner_map))
  83                inner_map = bpf_map_inc(inner_map, false);
  84        else
  85                inner_map = ERR_PTR(-EINVAL);
  86
  87        fdput(f);
  88        return inner_map;
  89}
  90
  91void bpf_map_fd_put_ptr(void *ptr)
  92{
  93        /* ptr->ops->map_free() has to go through one
  94         * rcu grace period by itself.
  95         */
  96        bpf_map_put(ptr);
  97}
  98
  99u32 bpf_map_fd_sys_lookup_elem(void *ptr)
 100{
 101        return ((struct bpf_map *)ptr)->id;
 102}
 103