// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2020 Facebook */
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#include <linux/bpf.h>
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#include <linux/fs.h>
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#include <linux/filter.h>
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#include <linux/kernel.h>
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#include <linux/btf_ids.h>
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struct bpf_iter_seq_map_info {
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u32 map_id;
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};
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static void *bpf_map_seq_start(struct seq_file *seq, loff_t *pos)
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{
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struct bpf_iter_seq_map_info *info = seq->private;
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struct bpf_map *map;
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map = bpf_map_get_curr_or_next(&info->map_id);
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if (!map)
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return NULL;
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if (*pos == 0)
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++*pos;
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return map;
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}
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static void *bpf_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
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{
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struct bpf_iter_seq_map_info *info = seq->private;
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++*pos;
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++info->map_id;
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bpf_map_put((struct bpf_map *)v);
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return bpf_map_get_curr_or_next(&info->map_id);
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}
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struct bpf_iter__bpf_map {
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__bpf_md_ptr(struct bpf_iter_meta *, meta);
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__bpf_md_ptr(struct bpf_map *, map);
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};
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DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map)
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static int __bpf_map_seq_show(struct seq_file *seq, void *v, bool in_stop)
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{
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struct bpf_iter__bpf_map ctx;
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struct bpf_iter_meta meta;
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struct bpf_prog *prog;
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int ret = 0;
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ctx.meta = &meta;
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ctx.map = v;
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meta.seq = seq;
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prog = bpf_iter_get_info(&meta, in_stop);
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if (prog)
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ret = bpf_iter_run_prog(prog, &ctx);
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return ret;
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}
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static int bpf_map_seq_show(struct seq_file *seq, void *v)
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{
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return __bpf_map_seq_show(seq, v, false);
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}
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static void bpf_map_seq_stop(struct seq_file *seq, void *v)
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{
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if (!v)
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(void)__bpf_map_seq_show(seq, v, true);
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else
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bpf_map_put((struct bpf_map *)v);
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}
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static const struct seq_operations bpf_map_seq_ops = {
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.start = bpf_map_seq_start,
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.next = bpf_map_seq_next,
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.stop = bpf_map_seq_stop,
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.show = bpf_map_seq_show,
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};
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BTF_ID_LIST(btf_bpf_map_id)
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BTF_ID(struct, bpf_map)
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static const struct bpf_iter_seq_info bpf_map_seq_info = {
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.seq_ops = &bpf_map_seq_ops,
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.init_seq_private = NULL,
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.fini_seq_private = NULL,
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.seq_priv_size = sizeof(struct bpf_iter_seq_map_info),
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};
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static struct bpf_iter_reg bpf_map_reg_info = {
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.target = "bpf_map",
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.ctx_arg_info_size = 1,
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.ctx_arg_info = {
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{ offsetof(struct bpf_iter__bpf_map, map),
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PTR_TO_BTF_ID_OR_NULL },
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},
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.seq_info = &bpf_map_seq_info,
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};
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static int bpf_iter_attach_map(struct bpf_prog *prog,
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union bpf_iter_link_info *linfo,
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struct bpf_iter_aux_info *aux)
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{
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u32 key_acc_size, value_acc_size, key_size, value_size;
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struct bpf_map *map;
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bool is_percpu = false;
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int err = -EINVAL;
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if (!linfo->map.map_fd)
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return -EBADF;
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map = bpf_map_get_with_uref(linfo->map.map_fd);
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if (IS_ERR(map))
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return PTR_ERR(map);
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if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
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map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
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map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
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is_percpu = true;
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else if (map->map_type != BPF_MAP_TYPE_HASH &&
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map->map_type != BPF_MAP_TYPE_LRU_HASH &&
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map->map_type != BPF_MAP_TYPE_ARRAY)
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goto put_map;
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key_acc_size = prog->aux->max_rdonly_access;
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value_acc_size = prog->aux->max_rdwr_access;
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key_size = map->key_size;
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if (!is_percpu)
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value_size = map->value_size;
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else
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value_size = round_up(map->value_size, 8) * num_possible_cpus();
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if (key_acc_size > key_size || value_acc_size > value_size) {
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err = -EACCES;
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goto put_map;
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}
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aux->map = map;
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return 0;
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put_map:
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bpf_map_put_with_uref(map);
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return err;
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}
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static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
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{
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bpf_map_put_with_uref(aux->map);
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}
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void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,
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struct seq_file *seq)
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{
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seq_printf(seq, "map_id:\t%u\n", aux->map->id);
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}
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int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,
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struct bpf_link_info *info)
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{
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info->iter.map.map_id = aux->map->id;
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return 0;
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}
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DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,
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struct bpf_map *map, void *key, void *value)
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static const struct bpf_iter_reg bpf_map_elem_reg_info = {
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.target = "bpf_map_elem",
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.attach_target = bpf_iter_attach_map,
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.detach_target = bpf_iter_detach_map,
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.show_fdinfo = bpf_iter_map_show_fdinfo,
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.fill_link_info = bpf_iter_map_fill_link_info,
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.ctx_arg_info_size = 2,
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.ctx_arg_info = {
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{ offsetof(struct bpf_iter__bpf_map_elem, key),
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PTR_TO_RDONLY_BUF_OR_NULL },
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{ offsetof(struct bpf_iter__bpf_map_elem, value),
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PTR_TO_RDWR_BUF_OR_NULL },
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},
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};
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static int __init bpf_map_iter_init(void)
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{
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int ret;
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bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;
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ret = bpf_iter_reg_target(&bpf_map_reg_info);
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if (ret)
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return ret;
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return bpf_iter_reg_target(&bpf_map_elem_reg_info);
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}
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late_initcall(bpf_map_iter_init);
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