diff options
Diffstat (limited to 'kernel/bpf/map_iter.c')
| -rw-r--r-- | kernel/bpf/map_iter.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/kernel/bpf/map_iter.c b/kernel/bpf/map_iter.c new file mode 100644 index 000000000..b0fa190b0 --- /dev/null +++ b/kernel/bpf/map_iter.c @@ -0,0 +1,195 @@ +// 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(btf_bpf_map_id) +BTF_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 }, + }, + .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); |