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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2020 Facebook */
#include <linux/bpf.h>
#include <linux/fs.h>
#include <linux/filter.h>
#include <linux/kernel.h>
#include <linux/btf_ids.h>
struct bpf_iter_seq_map_info {
u32 map_id;
};
static void *bpf_map_seq_start(struct seq_file *seq, loff_t *pos)
{
struct bpf_iter_seq_map_info *info = seq->private;
struct bpf_map *map;
map = bpf_map_get_curr_or_next(&info->map_id);
if (!map)
return NULL;
if (*pos == 0)
++*pos;
return map;
}
static void *bpf_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct bpf_iter_seq_map_info *info = seq->private;
++*pos;
++info->map_id;
bpf_map_put((struct bpf_map *)v);
return bpf_map_get_curr_or_next(&info->map_id);
}
struct bpf_iter__bpf_map {
__bpf_md_ptr(struct bpf_iter_meta *, meta);
__bpf_md_ptr(struct bpf_map *, map);
};
DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map)
static int __bpf_map_seq_show(struct seq_file *seq, void *v, bool in_stop)
{
struct bpf_iter__bpf_map ctx;
struct bpf_iter_meta meta;
struct bpf_prog *prog;
int ret = 0;
ctx.meta = &meta;
ctx.map = v;
meta.seq = seq;
prog = bpf_iter_get_info(&meta, in_stop);
if (prog)
ret = bpf_iter_run_prog(prog, &ctx);
return ret;
}
static int bpf_map_seq_show(struct seq_file *seq, void *v)
{
return __bpf_map_seq_show(seq, v, false);
}
static void bpf_map_seq_stop(struct seq_file *seq, void *v)
{
if (!v)
(void)__bpf_map_seq_show(seq, v, true);
else
bpf_map_put((struct bpf_map *)v);
}
static const struct seq_operations bpf_map_seq_ops = {
.start = bpf_map_seq_start,
.next = bpf_map_seq_next,
.stop = bpf_map_seq_stop,
.show = bpf_map_seq_show,
};
BTF_ID_LIST_GLOBAL_SINGLE(btf_bpf_map_id, struct, bpf_map)
static const struct bpf_iter_seq_info bpf_map_seq_info = {
.seq_ops = &bpf_map_seq_ops,
.init_seq_private = NULL,
.fini_seq_private = NULL,
.seq_priv_size = sizeof(struct bpf_iter_seq_map_info),
};
static struct bpf_iter_reg bpf_map_reg_info = {
.target = "bpf_map",
.ctx_arg_info_size = 1,
.ctx_arg_info = {
{ offsetof(struct bpf_iter__bpf_map, map),
PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
},
.seq_info = &bpf_map_seq_info,
};
static int bpf_iter_attach_map(struct bpf_prog *prog,
union bpf_iter_link_info *linfo,
struct bpf_iter_aux_info *aux)
{
u32 key_acc_size, value_acc_size, key_size, value_size;
struct bpf_map *map;
bool is_percpu = false;
int err = -EINVAL;
if (!linfo->map.map_fd)
return -EBADF;
map = bpf_map_get_with_uref(linfo->map.map_fd);
if (IS_ERR(map))
return PTR_ERR(map);
if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
is_percpu = true;
else if (map->map_type != BPF_MAP_TYPE_HASH &&
map->map_type != BPF_MAP_TYPE_LRU_HASH &&
map->map_type != BPF_MAP_TYPE_ARRAY)
goto put_map;
key_acc_size = prog->aux->max_rdonly_access;
value_acc_size = prog->aux->max_rdwr_access;
key_size = map->key_size;
if (!is_percpu)
value_size = map->value_size;
else
value_size = round_up(map->value_size, 8) * num_possible_cpus();
if (key_acc_size > key_size || value_acc_size > value_size) {
err = -EACCES;
goto put_map;
}
aux->map = map;
return 0;
put_map:
bpf_map_put_with_uref(map);
return err;
}
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)
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),
PTR_TO_BUF | PTR_MAYBE_NULL | MEM_RDONLY },
{ offsetof(struct bpf_iter__bpf_map_elem, value),
PTR_TO_BUF | PTR_MAYBE_NULL },
},
};
static int __init bpf_map_iter_init(void)
{
int ret;
bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;
ret = bpf_iter_reg_target(&bpf_map_reg_info);
if (ret)
return ret;
return bpf_iter_reg_target(&bpf_map_elem_reg_info);
}
late_initcall(bpf_map_iter_init);
__bpf_kfunc_start_defs();
__bpf_kfunc s64 bpf_map_sum_elem_count(const struct bpf_map *map)
{
s64 *pcount;
s64 ret = 0;
int cpu;
if (!map || !map->elem_count)
return 0;
for_each_possible_cpu(cpu) {
pcount = per_cpu_ptr(map->elem_count, cpu);
ret += READ_ONCE(*pcount);
}
return ret;
}
__bpf_kfunc_end_defs();
BTF_SET8_START(bpf_map_iter_kfunc_ids)
BTF_ID_FLAGS(func, bpf_map_sum_elem_count, KF_TRUSTED_ARGS)
BTF_SET8_END(bpf_map_iter_kfunc_ids)
static const struct btf_kfunc_id_set bpf_map_iter_kfunc_set = {
.owner = THIS_MODULE,
.set = &bpf_map_iter_kfunc_ids,
};
static int init_subsystem(void)
{
return register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &bpf_map_iter_kfunc_set);
}
late_initcall(init_subsystem);
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