projects/linux·blob master · refs

234 lines · 5.4 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (c) 2020 Facebook */
3#include <linux/bpf.h>
4#include <linux/fs.h>
5#include <linux/filter.h>
6#include <linux/kernel.h>
7#include <linux/btf_ids.h>
8
9struct bpf_iter_seq_map_info {
10 u32 map_id;
11};
12
13static void *bpf_map_seq_start(struct seq_file *seq, loff_t *pos)
14{
15 struct bpf_iter_seq_map_info *info = seq->private;
16 struct bpf_map *map;
17
18 map = bpf_map_get_curr_or_next(&info->map_id);
19 if (!map)
20 return NULL;
21
22 if (*pos == 0)
23 ++*pos;
24 return map;
25}
26
27static void *bpf_map_seq_next(struct seq_file *seq, void *v, loff_t *pos)
28{
29 struct bpf_iter_seq_map_info *info = seq->private;
30
31 ++*pos;
32 ++info->map_id;
33 bpf_map_put((struct bpf_map *)v);
34 return bpf_map_get_curr_or_next(&info->map_id);
35}
36
37struct bpf_iter__bpf_map {
38 __bpf_md_ptr(struct bpf_iter_meta *, meta);
39 __bpf_md_ptr(struct bpf_map *, map);
40};
41
42DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map)
43
44static int __bpf_map_seq_show(struct seq_file *seq, void *v, bool in_stop)
45{
46 struct bpf_iter__bpf_map ctx;
47 struct bpf_iter_meta meta;
48 struct bpf_prog *prog;
49 int ret = 0;
50
51 ctx.meta = &meta;
52 ctx.map = v;
53 meta.seq = seq;
54 prog = bpf_iter_get_info(&meta, in_stop);
55 if (prog)
56 ret = bpf_iter_run_prog(prog, &ctx);
57
58 return ret;
59}
60
61static int bpf_map_seq_show(struct seq_file *seq, void *v)
62{
63 return __bpf_map_seq_show(seq, v, false);
64}
65
66static void bpf_map_seq_stop(struct seq_file *seq, void *v)
67{
68 if (!v)
69 (void)__bpf_map_seq_show(seq, v, true);
70 else
71 bpf_map_put((struct bpf_map *)v);
72}
73
74static const struct seq_operations bpf_map_seq_ops = {
75 .start = bpf_map_seq_start,
76 .next = bpf_map_seq_next,
77 .stop = bpf_map_seq_stop,
78 .show = bpf_map_seq_show,
79};
80
81BTF_ID_LIST_GLOBAL_SINGLE(btf_bpf_map_id, struct, bpf_map)
82
83static const struct bpf_iter_seq_info bpf_map_seq_info = {
84 .seq_ops = &bpf_map_seq_ops,
85 .init_seq_private = NULL,
86 .fini_seq_private = NULL,
87 .seq_priv_size = sizeof(struct bpf_iter_seq_map_info),
88};
89
90static struct bpf_iter_reg bpf_map_reg_info = {
91 .target = "bpf_map",
92 .ctx_arg_info_size = 1,
93 .ctx_arg_info = {
94 { offsetof(struct bpf_iter__bpf_map, map),
95 PTR_TO_BTF_ID_OR_NULL | PTR_TRUSTED },
96 },
97 .seq_info = &bpf_map_seq_info,
98};
99
100static int bpf_iter_attach_map(struct bpf_prog *prog,
101 union bpf_iter_link_info *linfo,
102 struct bpf_iter_aux_info *aux)
103{
104 u32 key_acc_size, value_acc_size, key_size, value_size;
105 struct bpf_map *map;
106 bool is_percpu = false;
107 int err = -EINVAL;
108
109 if (!linfo->map.map_fd)
110 return -EBADF;
111
112 map = bpf_map_get_with_uref(linfo->map.map_fd);
113 if (IS_ERR(map))
114 return PTR_ERR(map);
115 if (map->excl_prog_sha) {
116 err = -EPERM;
117 goto put_map;
118 }
119
120 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
121 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
122 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
123 is_percpu = true;
124 else if (map->map_type != BPF_MAP_TYPE_HASH &&
125 map->map_type != BPF_MAP_TYPE_LRU_HASH &&
126 map->map_type != BPF_MAP_TYPE_ARRAY &&
127 map->map_type != BPF_MAP_TYPE_RHASH)
128 goto put_map;
129
130 key_acc_size = prog->aux->max_rdonly_access;
131 value_acc_size = prog->aux->max_rdwr_access;
132 key_size = map->key_size;
133 if (!is_percpu)
134 value_size = map->value_size;
135 else
136 value_size = round_up(map->value_size, 8) * num_possible_cpus();
137
138 if (key_acc_size > key_size || value_acc_size > value_size) {
139 err = -EACCES;
140 goto put_map;
141 }
142
143 aux->map = map;
144 return 0;
145
146put_map:
147 bpf_map_put_with_uref(map);
148 return err;
149}
150
151static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
152{
153 bpf_map_put_with_uref(aux->map);
154}
155
156void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,
157 struct seq_file *seq)
158{
159 seq_printf(seq, "map_id:\t%u\n", aux->map->id);
160}
161
162int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,
163 struct bpf_link_info *info)
164{
165 info->iter.map.map_id = aux->map->id;
166 return 0;
167}
168
169DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,
170 struct bpf_map *map, void *key, void *value)
171
172static const struct bpf_iter_reg bpf_map_elem_reg_info = {
173 .target = "bpf_map_elem",
174 .attach_target = bpf_iter_attach_map,
175 .detach_target = bpf_iter_detach_map,
176 .show_fdinfo = bpf_iter_map_show_fdinfo,
177 .fill_link_info = bpf_iter_map_fill_link_info,
178 .ctx_arg_info_size = 2,
179 .ctx_arg_info = {
180 { offsetof(struct bpf_iter__bpf_map_elem, key),
181 PTR_TO_BUF | PTR_MAYBE_NULL | MEM_RDONLY },
182 { offsetof(struct bpf_iter__bpf_map_elem, value),
183 PTR_TO_BUF | PTR_MAYBE_NULL },
184 },
185};
186
187static int __init bpf_map_iter_init(void)
188{
189 int ret;
190
191 bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;
192 ret = bpf_iter_reg_target(&bpf_map_reg_info);
193 if (ret)
194 return ret;
195
196 return bpf_iter_reg_target(&bpf_map_elem_reg_info);
197}
198
199late_initcall(bpf_map_iter_init);
200
201__bpf_kfunc_start_defs();
202
203__bpf_kfunc s64 bpf_map_sum_elem_count(const struct bpf_map *map)
204{
205 s64 *pcount;
206 s64 ret = 0;
207 int cpu;
208
209 if (!map || !map->elem_count)
210 return 0;
211
212 for_each_possible_cpu(cpu) {
213 pcount = per_cpu_ptr(map->elem_count, cpu);
214 ret += READ_ONCE(*pcount);
215 }
216 return ret;
217}
218
219__bpf_kfunc_end_defs();
220
221BTF_KFUNCS_START(bpf_map_iter_kfunc_ids)
222BTF_ID_FLAGS(func, bpf_map_sum_elem_count)
223BTF_KFUNCS_END(bpf_map_iter_kfunc_ids)
224
225static const struct btf_kfunc_id_set bpf_map_iter_kfunc_set = {
226 .owner = THIS_MODULE,
227 .set = &bpf_map_iter_kfunc_ids,
228};
229
230static int init_subsystem(void)
231{
232 return register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &bpf_map_iter_kfunc_set);
233}
234late_initcall(init_subsystem);