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1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3#include <linux/stddef.h>
4#include <linux/bpf.h>
5#include <bpf/bpf_helpers.h>
6#include <bpf/bpf_tracing.h>
7#include <../../../tools/include/linux/filter.h>
8#include <linux/btf.h>
9#include <string.h>
10#include <errno.h>
11#include "bpf_misc.h"
12
13char _license[] SEC("license") = "GPL";
14
15struct bpf_map {
16 int id;
17} __attribute__((preserve_access_index));
18
19struct args {
20 __u64 log_buf;
21 __u32 log_size;
22 int max_entries;
23 int map_fd;
24 int prog_fd;
25 int btf_fd;
26};
27
28#define BTF_INFO_ENC(kind, kind_flag, vlen) \
29 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
30#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
31#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
32 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
33#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
34 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
35 BTF_INT_ENC(encoding, bits_offset, bits)
36
37struct {
38 __uint(type, BPF_MAP_TYPE_ARRAY);
39 __type(key, int);
40 __type(value, union bpf_attr);
41 __uint(max_entries, 1);
42} bpf_attr_array SEC(".maps");
43
44struct inner_map_type {
45 __uint(type, BPF_MAP_TYPE_ARRAY);
46 __uint(key_size, 4);
47 __uint(value_size, 4);
48 __uint(max_entries, 1);
49} inner_map SEC(".maps");
50
51struct {
52 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
53 __type(key, int);
54 __type(value, int);
55 __uint(max_entries, 1);
56 __array(values, struct inner_map_type);
57} outer_array_map SEC(".maps") = {
58 .values = {
59 [0] = &inner_map,
60 },
61};
62
63static inline __u64 ptr_to_u64(const void *ptr)
64{
65 return (__u64) (unsigned long) ptr;
66}
67
68static int btf_load(void)
69{
70 struct btf_blob {
71 struct btf_header btf_hdr;
72 __u32 types[8];
73 __u32 str;
74 } raw_btf = {
75 .btf_hdr = {
76 .magic = BTF_MAGIC,
77 .version = BTF_VERSION,
78 .hdr_len = sizeof(struct btf_header),
79 .type_len = sizeof(__u32) * 8,
80 .str_off = sizeof(__u32) * 8,
81 .str_len = sizeof(__u32),
82 },
83 .types = {
84 /* long */
85 BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 64, 8), /* [1] */
86 /* unsigned long */
87 BTF_TYPE_INT_ENC(0, 0, 0, 64, 8), /* [2] */
88 },
89 };
90 static union bpf_attr btf_load_attr = {
91 .btf_size = sizeof(raw_btf),
92 };
93
94 btf_load_attr.btf = (long)&raw_btf;
95 return bpf_sys_bpf(BPF_BTF_LOAD, &btf_load_attr, sizeof(btf_load_attr));
96}
97
98SEC("syscall")
99int load_prog(struct args *ctx)
100{
101 static char license[] = "GPL";
102 static struct bpf_insn insns[] = {
103 BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
104 BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
105 BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
106 BPF_LD_MAP_FD(BPF_REG_1, 0),
107 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
108 BPF_MOV64_IMM(BPF_REG_0, 0),
109 BPF_EXIT_INSN(),
110 };
111 static union bpf_attr map_create_attr = {
112 .map_type = BPF_MAP_TYPE_HASH,
113 .key_size = 8,
114 .value_size = 8,
115 .btf_key_type_id = 1,
116 .btf_value_type_id = 2,
117 };
118 static union bpf_attr map_update_attr = { .map_fd = 1, };
119 static __u64 key = 12;
120 static __u64 value = 34;
121 static union bpf_attr prog_load_attr = {
122 .prog_type = BPF_PROG_TYPE_XDP,
123 .insn_cnt = ARRAY_SIZE(insns),
124 };
125 int ret;
126
127 ret = btf_load();
128 if (ret <= 0)
129 return ret;
130
131 ctx->btf_fd = ret;
132 map_create_attr.max_entries = ctx->max_entries;
133 map_create_attr.btf_fd = ret;
134
135 prog_load_attr.license = ptr_to_u64(license);
136 prog_load_attr.insns = ptr_to_u64(insns);
137 prog_load_attr.log_buf = ctx->log_buf;
138 prog_load_attr.log_size = ctx->log_size;
139 prog_load_attr.log_level = 1;
140
141 ret = bpf_sys_bpf(BPF_MAP_CREATE, &map_create_attr, sizeof(map_create_attr));
142 if (ret <= 0)
143 return ret;
144 ctx->map_fd = ret;
145 insns[3].imm = ret;
146
147 map_update_attr.map_fd = ret;
148 map_update_attr.key = ptr_to_u64(&key);
149 map_update_attr.value = ptr_to_u64(&value);
150 ret = bpf_sys_bpf(BPF_MAP_UPDATE_ELEM, &map_update_attr, sizeof(map_update_attr));
151 if (ret < 0)
152 return ret;
153
154 ret = bpf_sys_bpf(BPF_PROG_LOAD, &prog_load_attr, sizeof(prog_load_attr));
155 if (ret <= 0)
156 return ret;
157 ctx->prog_fd = ret;
158 return 1;
159}
160
161SEC("syscall")
162int update_outer_map(void *ctx)
163{
164 int zero = 0, ret = 0, outer_fd = -1, inner_fd = -1, err;
165 const int attr_sz = sizeof(union bpf_attr);
166 union bpf_attr *attr;
167
168 attr = bpf_map_lookup_elem((struct bpf_map *)&bpf_attr_array, &zero);
169 if (!attr)
170 goto out;
171
172 memset(attr, 0, attr_sz);
173 attr->map_id = ((struct bpf_map *)&outer_array_map)->id;
174 outer_fd = bpf_sys_bpf(BPF_MAP_GET_FD_BY_ID, attr, attr_sz);
175 if (outer_fd < 0)
176 goto out;
177
178 memset(attr, 0, attr_sz);
179 attr->map_type = BPF_MAP_TYPE_ARRAY;
180 attr->key_size = 4;
181 attr->value_size = 4;
182 attr->max_entries = 1;
183 inner_fd = bpf_sys_bpf(BPF_MAP_CREATE, attr, attr_sz);
184 if (inner_fd < 0)
185 goto out;
186
187 memset(attr, 0, attr_sz);
188 attr->map_fd = outer_fd;
189 attr->key = ptr_to_u64(&zero);
190 attr->value = ptr_to_u64(&inner_fd);
191 err = bpf_sys_bpf(BPF_MAP_UPDATE_ELEM, attr, attr_sz);
192 if (err)
193 goto out;
194
195 memset(attr, 0, attr_sz);
196 attr->map_fd = outer_fd;
197 attr->key = ptr_to_u64(&zero);
198 err = bpf_sys_bpf(BPF_MAP_DELETE_ELEM, attr, attr_sz);
199 if (err)
200 goto out;
201 ret = 1;
202out:
203 if (inner_fd >= 0)
204 bpf_sys_close(inner_fd);
205 if (outer_fd >= 0)
206 bpf_sys_close(outer_fd);
207 return ret;
208}
1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (c) 2021 Facebook */
3#include <linux/stddef.h>
4#include <linux/bpf.h>
5#include <bpf/bpf_helpers.h>
6#include <bpf/bpf_tracing.h>
7#include <../../../tools/include/linux/filter.h>
8#include <linux/btf.h>
9
10char _license[] SEC("license") = "GPL";
11
12struct args {
13 __u64 log_buf;
14 __u32 log_size;
15 int max_entries;
16 int map_fd;
17 int prog_fd;
18 int btf_fd;
19};
20
21#define BTF_INFO_ENC(kind, kind_flag, vlen) \
22 ((!!(kind_flag) << 31) | ((kind) << 24) | ((vlen) & BTF_MAX_VLEN))
23#define BTF_TYPE_ENC(name, info, size_or_type) (name), (info), (size_or_type)
24#define BTF_INT_ENC(encoding, bits_offset, nr_bits) \
25 ((encoding) << 24 | (bits_offset) << 16 | (nr_bits))
26#define BTF_TYPE_INT_ENC(name, encoding, bits_offset, bits, sz) \
27 BTF_TYPE_ENC(name, BTF_INFO_ENC(BTF_KIND_INT, 0, 0), sz), \
28 BTF_INT_ENC(encoding, bits_offset, bits)
29
30static int btf_load(void)
31{
32 struct btf_blob {
33 struct btf_header btf_hdr;
34 __u32 types[8];
35 __u32 str;
36 } raw_btf = {
37 .btf_hdr = {
38 .magic = BTF_MAGIC,
39 .version = BTF_VERSION,
40 .hdr_len = sizeof(struct btf_header),
41 .type_len = sizeof(__u32) * 8,
42 .str_off = sizeof(__u32) * 8,
43 .str_len = sizeof(__u32),
44 },
45 .types = {
46 /* long */
47 BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 64, 8), /* [1] */
48 /* unsigned long */
49 BTF_TYPE_INT_ENC(0, 0, 0, 64, 8), /* [2] */
50 },
51 };
52 static union bpf_attr btf_load_attr = {
53 .btf_size = sizeof(raw_btf),
54 };
55
56 btf_load_attr.btf = (long)&raw_btf;
57 return bpf_sys_bpf(BPF_BTF_LOAD, &btf_load_attr, sizeof(btf_load_attr));
58}
59
60SEC("syscall")
61int bpf_prog(struct args *ctx)
62{
63 static char license[] = "GPL";
64 static struct bpf_insn insns[] = {
65 BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
66 BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
67 BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
68 BPF_LD_MAP_FD(BPF_REG_1, 0),
69 BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
70 BPF_MOV64_IMM(BPF_REG_0, 0),
71 BPF_EXIT_INSN(),
72 };
73 static union bpf_attr map_create_attr = {
74 .map_type = BPF_MAP_TYPE_HASH,
75 .key_size = 8,
76 .value_size = 8,
77 .btf_key_type_id = 1,
78 .btf_value_type_id = 2,
79 };
80 static union bpf_attr map_update_attr = { .map_fd = 1, };
81 static __u64 key = 12;
82 static __u64 value = 34;
83 static union bpf_attr prog_load_attr = {
84 .prog_type = BPF_PROG_TYPE_XDP,
85 .insn_cnt = sizeof(insns) / sizeof(insns[0]),
86 };
87 int ret;
88
89 ret = btf_load();
90 if (ret <= 0)
91 return ret;
92
93 ctx->btf_fd = ret;
94 map_create_attr.max_entries = ctx->max_entries;
95 map_create_attr.btf_fd = ret;
96
97 prog_load_attr.license = (long) license;
98 prog_load_attr.insns = (long) insns;
99 prog_load_attr.log_buf = ctx->log_buf;
100 prog_load_attr.log_size = ctx->log_size;
101 prog_load_attr.log_level = 1;
102
103 ret = bpf_sys_bpf(BPF_MAP_CREATE, &map_create_attr, sizeof(map_create_attr));
104 if (ret <= 0)
105 return ret;
106 ctx->map_fd = ret;
107 insns[3].imm = ret;
108
109 map_update_attr.map_fd = ret;
110 map_update_attr.key = (long) &key;
111 map_update_attr.value = (long) &value;
112 ret = bpf_sys_bpf(BPF_MAP_UPDATE_ELEM, &map_update_attr, sizeof(map_update_attr));
113 if (ret < 0)
114 return ret;
115
116 ret = bpf_sys_bpf(BPF_PROG_LOAD, &prog_load_attr, sizeof(prog_load_attr));
117 if (ret <= 0)
118 return ret;
119 ctx->prog_fd = ret;
120 return 1;
121}