1
2
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(btf_bpf_map_id)
82BTF_ID(struct, bpf_map)
83
84static const struct bpf_iter_seq_info bpf_map_seq_info = {
85 .seq_ops = &bpf_map_seq_ops,
86 .init_seq_private = NULL,
87 .fini_seq_private = NULL,
88 .seq_priv_size = sizeof(struct bpf_iter_seq_map_info),
89};
90
91static struct bpf_iter_reg bpf_map_reg_info = {
92 .target = "bpf_map",
93 .ctx_arg_info_size = 1,
94 .ctx_arg_info = {
95 { offsetof(struct bpf_iter__bpf_map, map),
96 PTR_TO_BTF_ID_OR_NULL },
97 },
98 .seq_info = &bpf_map_seq_info,
99};
100
101static int bpf_iter_attach_map(struct bpf_prog *prog,
102 union bpf_iter_link_info *linfo,
103 struct bpf_iter_aux_info *aux)
104{
105 u32 key_acc_size, value_acc_size, key_size, value_size;
106 struct bpf_map *map;
107 bool is_percpu = false;
108 int err = -EINVAL;
109
110 if (!linfo->map.map_fd)
111 return -EBADF;
112
113 map = bpf_map_get_with_uref(linfo->map.map_fd);
114 if (IS_ERR(map))
115 return PTR_ERR(map);
116
117 if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
118 map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH ||
119 map->map_type == BPF_MAP_TYPE_PERCPU_ARRAY)
120 is_percpu = true;
121 else if (map->map_type != BPF_MAP_TYPE_HASH &&
122 map->map_type != BPF_MAP_TYPE_LRU_HASH &&
123 map->map_type != BPF_MAP_TYPE_ARRAY)
124 goto put_map;
125
126 key_acc_size = prog->aux->max_rdonly_access;
127 value_acc_size = prog->aux->max_rdwr_access;
128 key_size = map->key_size;
129 if (!is_percpu)
130 value_size = map->value_size;
131 else
132 value_size = round_up(map->value_size, 8) * num_possible_cpus();
133
134 if (key_acc_size > key_size || value_acc_size > value_size) {
135 err = -EACCES;
136 goto put_map;
137 }
138
139 aux->map = map;
140 return 0;
141
142put_map:
143 bpf_map_put_with_uref(map);
144 return err;
145}
146
147static void bpf_iter_detach_map(struct bpf_iter_aux_info *aux)
148{
149 bpf_map_put_with_uref(aux->map);
150}
151
152void bpf_iter_map_show_fdinfo(const struct bpf_iter_aux_info *aux,
153 struct seq_file *seq)
154{
155 seq_printf(seq, "map_id:\t%u\n", aux->map->id);
156}
157
158int bpf_iter_map_fill_link_info(const struct bpf_iter_aux_info *aux,
159 struct bpf_link_info *info)
160{
161 info->iter.map.map_id = aux->map->id;
162 return 0;
163}
164
165DEFINE_BPF_ITER_FUNC(bpf_map_elem, struct bpf_iter_meta *meta,
166 struct bpf_map *map, void *key, void *value)
167
168static const struct bpf_iter_reg bpf_map_elem_reg_info = {
169 .target = "bpf_map_elem",
170 .attach_target = bpf_iter_attach_map,
171 .detach_target = bpf_iter_detach_map,
172 .show_fdinfo = bpf_iter_map_show_fdinfo,
173 .fill_link_info = bpf_iter_map_fill_link_info,
174 .ctx_arg_info_size = 2,
175 .ctx_arg_info = {
176 { offsetof(struct bpf_iter__bpf_map_elem, key),
177 PTR_TO_RDONLY_BUF_OR_NULL },
178 { offsetof(struct bpf_iter__bpf_map_elem, value),
179 PTR_TO_RDWR_BUF_OR_NULL },
180 },
181};
182
183static int __init bpf_map_iter_init(void)
184{
185 int ret;
186
187 bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;
188 ret = bpf_iter_reg_target(&bpf_map_reg_info);
189 if (ret)
190 return ret;
191
192 return bpf_iter_reg_target(&bpf_map_elem_reg_info);
193}
194
195late_initcall(bpf_map_iter_init);
196
