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
9 struct bpf_iter_seq_map_info {
10 u32 map_id;
11 };
12
13 static 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
27 static 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
37 struct bpf_iter__bpf_map {
38 __bpf_md_ptr(struct bpf_iter_meta *, meta);
39 __bpf_md_ptr(struct bpf_map *, map);
40 };
41
42 DEFINE_BPF_ITER_FUNC(bpf_map, struct bpf_iter_meta *meta, struct bpf_map *map)
43
44 static 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
61 static int bpf_map_seq_show(struct seq_file *seq, void *v)
62 {
63 return __bpf_map_seq_show(seq, v, false);
64 }
65
66 static 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
74 static 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
81 BTF_ID_LIST_GLOBAL_SINGLE(btf_bpf_map_id, struct, bpf_map)
82
83 static 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
90 static 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
100 static 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
116 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
117 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
118 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
119 is_percpu = true;
120 else if (map->map_type != BPF_MAP_TYPE_HASH &&
121 map->map_type != BPF_MAP_TYPE_LRU_HASH &&
122 map->map_type != BPF_MAP_TYPE_ARRAY)
123 goto put_map;
124
125 key_acc_size = prog->aux->max_rdonly_access;
126 value_acc_size = prog->aux->max_rdwr_access;
127 key_size = map->key_size;
128 if (!is_percpu)
129 value_size = map->value_size;
130 else
131 value_size = round_up(map->value_size, 8) * num_possible_cpus();
132
133 if (key_acc_size > key_size || value_acc_size > value_size) {
134 err = -EACCES;
135 goto put_map;
136 }
137
138 aux->map = map;
139 return 0;
140
141 put_map:
142 bpf_map_put_with_uref(map);
143 return err;
144 }
145
146 static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
147 {
148 bpf_map_put_with_uref(aux->map);
149 }
150
151 void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,
152 struct seq_file *seq)
153 {
154 seq_printf(seq, "map_id:\t%u\n", aux->map->id);
155 }
156
157 int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,
158 struct bpf_link_info *info)
159 {
160 info->iter.map.map_id = aux->map->id;
161 return 0;
162 }
163
164 DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,
165 struct bpf_map *map, void *key, void *value)
166
167 static const struct bpf_iter_reg bpf_map_elem_reg_info = {
168 .target = "bpf_map_elem",
169 .attach_target = bpf_iter_attach_map,
170 .detach_target = bpf_iter_detach_map,
171 .show_fdinfo = bpf_iter_map_show_fdinfo,
172 .fill_link_info = bpf_iter_map_fill_link_info,
173 .ctx_arg_info_size = 2,
174 .ctx_arg_info = {
175 { offsetof(struct bpf_iter__bpf_map_elem, key),
176 PTR_TO_BUF | PTR_MAYBE_NULL | MEM_RDONLY },
177 { offsetof(struct bpf_iter__bpf_map_elem, value),
178 PTR_TO_BUF | PTR_MAYBE_NULL },
179 },
180 };
181
182 static int __init bpf_map_iter_init(void)
183 {
184 int ret;
185
186 bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;
187 ret = bpf_iter_reg_target(&bpf_map_reg_info);
188 if (ret)
189 return ret;
190
191 return bpf_iter_reg_target(&bpf_map_elem_reg_info);
192 }
193
194 late_initcall(bpf_map_iter_init);
195
196 __bpf_kfunc_start_defs();
197
198 __bpf_kfunc s64 bpf_map_sum_elem_count(const struct bpf_map *map)
199 {
200 s64 *pcount;
201 s64 ret = 0;
202 int cpu;
203
204 if (!map || !map->elem_count)
205 return 0;
206
207 for_each_possible_cpu(cpu) {
208 pcount = per_cpu_ptr(map->elem_count, cpu);
209 ret += READ_ONCE(*pcount);
210 }
211 return ret;
212 }
213
214 __bpf_kfunc_end_defs();
215
216 BTF_KFUNCS_START(bpf_map_iter_kfunc_ids)
217 BTF_ID_FLAGS(func, bpf_map_sum_elem_count, KF_TRUSTED_ARGS)
218 BTF_KFUNCS_END(bpf_map_iter_kfunc_ids)
219
220 static const struct btf_kfunc_id_set bpf_map_iter_kfunc_set = {
221 .owner = THIS_MODULE,
222 .set = &bpf_map_iter_kfunc_ids,
223 };
224
225 static int init_subsystem(void)
226 {
227 return register_btf_kfunc_id_set(BPF_PROG_TYPE_UNSPEC, &bpf_map_iter_kfunc_set);
228 }
229 late_initcall(init_subsystem);
230
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