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1/*
2 * Example wrapper around BPF macros.
3 *
4 * Copyright (c) 2012 The Chromium OS Authors <chromium-os-dev@chromium.org>
5 * Author: Will Drewry <wad@chromium.org>
6 *
7 * The code may be used by anyone for any purpose,
8 * and can serve as a starting point for developing
9 * applications using prctl(PR_SET_SECCOMP, 2, ...).
10 *
11 * No guarantees are provided with respect to the correctness
12 * or functionality of this code.
13 */
14#ifndef __BPF_HELPER_H__
15#define __BPF_HELPER_H__
16
17#include <asm/bitsperlong.h> /* for __BITS_PER_LONG */
18#include <endian.h>
19#include <linux/filter.h>
20#include <linux/seccomp.h> /* for seccomp_data */
21#include <linux/types.h>
22#include <linux/unistd.h>
23#include <stddef.h>
24
25#define BPF_LABELS_MAX 256
26struct bpf_labels {
27 int count;
28 struct __bpf_label {
29 const char *label;
30 __u32 location;
31 } labels[BPF_LABELS_MAX];
32};
33
34int bpf_resolve_jumps(struct bpf_labels *labels,
35 struct sock_filter *filter, size_t count);
36__u32 seccomp_bpf_label(struct bpf_labels *labels, const char *label);
37void seccomp_bpf_print(struct sock_filter *filter, size_t count);
38
39#define JUMP_JT 0xff
40#define JUMP_JF 0xff
41#define LABEL_JT 0xfe
42#define LABEL_JF 0xfe
43
44#define ALLOW \
45 BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
46#define DENY \
47 BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)
48#define JUMP(labels, label) \
49 BPF_JUMP(BPF_JMP+BPF_JA, FIND_LABEL((labels), (label)), \
50 JUMP_JT, JUMP_JF)
51#define LABEL(labels, label) \
52 BPF_JUMP(BPF_JMP+BPF_JA, FIND_LABEL((labels), (label)), \
53 LABEL_JT, LABEL_JF)
54#define SYSCALL(nr, jt) \
55 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (nr), 0, 1), \
56 jt
57
58/* Lame, but just an example */
59#define FIND_LABEL(labels, label) seccomp_bpf_label((labels), #label)
60
61#define EXPAND(...) __VA_ARGS__
62
63/* Ensure that we load the logically correct offset. */
64#if __BYTE_ORDER == __LITTLE_ENDIAN
65#define LO_ARG(idx) offsetof(struct seccomp_data, args[(idx)])
66#elif __BYTE_ORDER == __BIG_ENDIAN
67#define LO_ARG(idx) offsetof(struct seccomp_data, args[(idx)]) + sizeof(__u32)
68#else
69#error "Unknown endianness"
70#endif
71
72/* Map all width-sensitive operations */
73#if __BITS_PER_LONG == 32
74
75#define JEQ(x, jt) JEQ32(x, EXPAND(jt))
76#define JNE(x, jt) JNE32(x, EXPAND(jt))
77#define JGT(x, jt) JGT32(x, EXPAND(jt))
78#define JLT(x, jt) JLT32(x, EXPAND(jt))
79#define JGE(x, jt) JGE32(x, EXPAND(jt))
80#define JLE(x, jt) JLE32(x, EXPAND(jt))
81#define JA(x, jt) JA32(x, EXPAND(jt))
82#define ARG(i) ARG_32(i)
83
84#elif __BITS_PER_LONG == 64
85
86/* Ensure that we load the logically correct offset. */
87#if __BYTE_ORDER == __LITTLE_ENDIAN
88#define ENDIAN(_lo, _hi) _lo, _hi
89#define HI_ARG(idx) offsetof(struct seccomp_data, args[(idx)]) + sizeof(__u32)
90#elif __BYTE_ORDER == __BIG_ENDIAN
91#define ENDIAN(_lo, _hi) _hi, _lo
92#define HI_ARG(idx) offsetof(struct seccomp_data, args[(idx)])
93#endif
94
95union arg64 {
96 struct {
97 __u32 ENDIAN(lo32, hi32);
98 };
99 __u64 u64;
100};
101
102#define JEQ(x, jt) \
103 JEQ64(((union arg64){.u64 = (x)}).lo32, \
104 ((union arg64){.u64 = (x)}).hi32, \
105 EXPAND(jt))
106#define JGT(x, jt) \
107 JGT64(((union arg64){.u64 = (x)}).lo32, \
108 ((union arg64){.u64 = (x)}).hi32, \
109 EXPAND(jt))
110#define JGE(x, jt) \
111 JGE64(((union arg64){.u64 = (x)}).lo32, \
112 ((union arg64){.u64 = (x)}).hi32, \
113 EXPAND(jt))
114#define JNE(x, jt) \
115 JNE64(((union arg64){.u64 = (x)}).lo32, \
116 ((union arg64){.u64 = (x)}).hi32, \
117 EXPAND(jt))
118#define JLT(x, jt) \
119 JLT64(((union arg64){.u64 = (x)}).lo32, \
120 ((union arg64){.u64 = (x)}).hi32, \
121 EXPAND(jt))
122#define JLE(x, jt) \
123 JLE64(((union arg64){.u64 = (x)}).lo32, \
124 ((union arg64){.u64 = (x)}).hi32, \
125 EXPAND(jt))
126
127#define JA(x, jt) \
128 JA64(((union arg64){.u64 = (x)}).lo32, \
129 ((union arg64){.u64 = (x)}).hi32, \
130 EXPAND(jt))
131#define ARG(i) ARG_64(i)
132
133#else
134#error __BITS_PER_LONG value unusable.
135#endif
136
137/* Loads the arg into A */
138#define ARG_32(idx) \
139 BPF_STMT(BPF_LD+BPF_W+BPF_ABS, LO_ARG(idx))
140
141/* Loads hi into A and lo in X */
142#define ARG_64(idx) \
143 BPF_STMT(BPF_LD+BPF_W+BPF_ABS, LO_ARG(idx)), \
144 BPF_STMT(BPF_ST, 0), /* lo -> M[0] */ \
145 BPF_STMT(BPF_LD+BPF_W+BPF_ABS, HI_ARG(idx)), \
146 BPF_STMT(BPF_ST, 1) /* hi -> M[1] */
147
148#define JEQ32(value, jt) \
149 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (value), 0, 1), \
150 jt
151
152#define JNE32(value, jt) \
153 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (value), 1, 0), \
154 jt
155
156/* Checks the lo, then swaps to check the hi. A=lo,X=hi */
157#define JEQ64(lo, hi, jt) \
158 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \
159 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
160 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (lo), 0, 2), \
161 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
162 jt, \
163 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
164
165#define JNE64(lo, hi, jt) \
166 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 5, 0), \
167 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
168 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (lo), 2, 0), \
169 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
170 jt, \
171 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
172
173#define JA32(value, jt) \
174 BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (value), 0, 1), \
175 jt
176
177#define JA64(lo, hi, jt) \
178 BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (hi), 3, 0), \
179 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
180 BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (lo), 0, 2), \
181 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
182 jt, \
183 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
184
185#define JGE32(value, jt) \
186 BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (value), 0, 1), \
187 jt
188
189#define JLT32(value, jt) \
190 BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (value), 1, 0), \
191 jt
192
193/* Shortcut checking if hi > arg.hi. */
194#define JGE64(lo, hi, jt) \
195 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (hi), 4, 0), \
196 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \
197 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
198 BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (lo), 0, 2), \
199 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
200 jt, \
201 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
202
203#define JLT64(lo, hi, jt) \
204 BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (hi), 0, 4), \
205 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \
206 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
207 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (lo), 2, 0), \
208 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
209 jt, \
210 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
211
212#define JGT32(value, jt) \
213 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (value), 0, 1), \
214 jt
215
216#define JLE32(value, jt) \
217 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (value), 1, 0), \
218 jt
219
220/* Check hi > args.hi first, then do the GE checking */
221#define JGT64(lo, hi, jt) \
222 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (hi), 4, 0), \
223 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \
224 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
225 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (lo), 0, 2), \
226 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
227 jt, \
228 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
229
230#define JLE64(lo, hi, jt) \
231 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (hi), 6, 0), \
232 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 3), \
233 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
234 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (lo), 2, 0), \
235 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
236 jt, \
237 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
238
239#define LOAD_SYSCALL_NR \
240 BPF_STMT(BPF_LD+BPF_W+BPF_ABS, \
241 offsetof(struct seccomp_data, nr))
242
243#endif /* __BPF_HELPER_H__ */
1/*
2 * Example wrapper around BPF macros.
3 *
4 * Copyright (c) 2012 The Chromium OS Authors <chromium-os-dev@chromium.org>
5 * Author: Will Drewry <wad@chromium.org>
6 *
7 * The code may be used by anyone for any purpose,
8 * and can serve as a starting point for developing
9 * applications using prctl(PR_SET_SECCOMP, 2, ...).
10 *
11 * No guarantees are provided with respect to the correctness
12 * or functionality of this code.
13 */
14#ifndef __BPF_HELPER_H__
15#define __BPF_HELPER_H__
16
17#include <asm/bitsperlong.h> /* for __BITS_PER_LONG */
18#include <endian.h>
19#include <linux/filter.h>
20#include <linux/seccomp.h> /* for seccomp_data */
21#include <linux/types.h>
22#include <linux/unistd.h>
23#include <stddef.h>
24
25#define BPF_LABELS_MAX 256
26struct bpf_labels {
27 int count;
28 struct __bpf_label {
29 const char *label;
30 __u32 location;
31 } labels[BPF_LABELS_MAX];
32};
33
34int bpf_resolve_jumps(struct bpf_labels *labels,
35 struct sock_filter *filter, size_t count);
36__u32 seccomp_bpf_label(struct bpf_labels *labels, const char *label);
37void seccomp_bpf_print(struct sock_filter *filter, size_t count);
38
39#define JUMP_JT 0xff
40#define JUMP_JF 0xff
41#define LABEL_JT 0xfe
42#define LABEL_JF 0xfe
43
44#define ALLOW \
45 BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW)
46#define DENY \
47 BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_KILL)
48#define JUMP(labels, label) \
49 BPF_JUMP(BPF_JMP+BPF_JA, FIND_LABEL((labels), (label)), \
50 JUMP_JT, JUMP_JF)
51#define LABEL(labels, label) \
52 BPF_JUMP(BPF_JMP+BPF_JA, FIND_LABEL((labels), (label)), \
53 LABEL_JT, LABEL_JF)
54#define SYSCALL(nr, jt) \
55 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (nr), 0, 1), \
56 jt
57
58/* Lame, but just an example */
59#define FIND_LABEL(labels, label) seccomp_bpf_label((labels), #label)
60
61#define EXPAND(...) __VA_ARGS__
62
63/* Ensure that we load the logically correct offset. */
64#if __BYTE_ORDER == __LITTLE_ENDIAN
65#define LO_ARG(idx) offsetof(struct seccomp_data, args[(idx)])
66#elif __BYTE_ORDER == __BIG_ENDIAN
67#define LO_ARG(idx) offsetof(struct seccomp_data, args[(idx)]) + sizeof(__u32)
68#else
69#error "Unknown endianness"
70#endif
71
72/* Map all width-sensitive operations */
73#if __BITS_PER_LONG == 32
74
75#define JEQ(x, jt) JEQ32(x, EXPAND(jt))
76#define JNE(x, jt) JNE32(x, EXPAND(jt))
77#define JGT(x, jt) JGT32(x, EXPAND(jt))
78#define JLT(x, jt) JLT32(x, EXPAND(jt))
79#define JGE(x, jt) JGE32(x, EXPAND(jt))
80#define JLE(x, jt) JLE32(x, EXPAND(jt))
81#define JA(x, jt) JA32(x, EXPAND(jt))
82#define ARG(i) ARG_32(i)
83
84#elif __BITS_PER_LONG == 64
85
86/* Ensure that we load the logically correct offset. */
87#if __BYTE_ORDER == __LITTLE_ENDIAN
88#define ENDIAN(_lo, _hi) _lo, _hi
89#define HI_ARG(idx) offsetof(struct seccomp_data, args[(idx)]) + sizeof(__u32)
90#elif __BYTE_ORDER == __BIG_ENDIAN
91#define ENDIAN(_lo, _hi) _hi, _lo
92#define HI_ARG(idx) offsetof(struct seccomp_data, args[(idx)])
93#endif
94
95union arg64 {
96 struct {
97 __u32 ENDIAN(lo32, hi32);
98 };
99 __u64 u64;
100};
101
102#define JEQ(x, jt) \
103 JEQ64(((union arg64){.u64 = (x)}).lo32, \
104 ((union arg64){.u64 = (x)}).hi32, \
105 EXPAND(jt))
106#define JGT(x, jt) \
107 JGT64(((union arg64){.u64 = (x)}).lo32, \
108 ((union arg64){.u64 = (x)}).hi32, \
109 EXPAND(jt))
110#define JGE(x, jt) \
111 JGE64(((union arg64){.u64 = (x)}).lo32, \
112 ((union arg64){.u64 = (x)}).hi32, \
113 EXPAND(jt))
114#define JNE(x, jt) \
115 JNE64(((union arg64){.u64 = (x)}).lo32, \
116 ((union arg64){.u64 = (x)}).hi32, \
117 EXPAND(jt))
118#define JLT(x, jt) \
119 JLT64(((union arg64){.u64 = (x)}).lo32, \
120 ((union arg64){.u64 = (x)}).hi32, \
121 EXPAND(jt))
122#define JLE(x, jt) \
123 JLE64(((union arg64){.u64 = (x)}).lo32, \
124 ((union arg64){.u64 = (x)}).hi32, \
125 EXPAND(jt))
126
127#define JA(x, jt) \
128 JA64(((union arg64){.u64 = (x)}).lo32, \
129 ((union arg64){.u64 = (x)}).hi32, \
130 EXPAND(jt))
131#define ARG(i) ARG_64(i)
132
133#else
134#error __BITS_PER_LONG value unusable.
135#endif
136
137/* Loads the arg into A */
138#define ARG_32(idx) \
139 BPF_STMT(BPF_LD+BPF_W+BPF_ABS, LO_ARG(idx))
140
141/* Loads hi into A and lo in X */
142#define ARG_64(idx) \
143 BPF_STMT(BPF_LD+BPF_W+BPF_ABS, LO_ARG(idx)), \
144 BPF_STMT(BPF_ST, 0), /* lo -> M[0] */ \
145 BPF_STMT(BPF_LD+BPF_W+BPF_ABS, HI_ARG(idx)), \
146 BPF_STMT(BPF_ST, 1) /* hi -> M[1] */
147
148#define JEQ32(value, jt) \
149 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (value), 0, 1), \
150 jt
151
152#define JNE32(value, jt) \
153 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (value), 1, 0), \
154 jt
155
156/* Checks the lo, then swaps to check the hi. A=lo,X=hi */
157#define JEQ64(lo, hi, jt) \
158 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \
159 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
160 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (lo), 0, 2), \
161 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
162 jt, \
163 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
164
165#define JNE64(lo, hi, jt) \
166 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 5, 0), \
167 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
168 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (lo), 2, 0), \
169 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
170 jt, \
171 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
172
173#define JA32(value, jt) \
174 BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (value), 0, 1), \
175 jt
176
177#define JA64(lo, hi, jt) \
178 BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (hi), 3, 0), \
179 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
180 BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (lo), 0, 2), \
181 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
182 jt, \
183 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
184
185#define JGE32(value, jt) \
186 BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (value), 0, 1), \
187 jt
188
189#define JLT32(value, jt) \
190 BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (value), 1, 0), \
191 jt
192
193/* Shortcut checking if hi > arg.hi. */
194#define JGE64(lo, hi, jt) \
195 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (hi), 4, 0), \
196 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \
197 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
198 BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (lo), 0, 2), \
199 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
200 jt, \
201 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
202
203#define JLT64(lo, hi, jt) \
204 BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (hi), 0, 4), \
205 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \
206 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
207 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (lo), 2, 0), \
208 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
209 jt, \
210 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
211
212#define JGT32(value, jt) \
213 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (value), 0, 1), \
214 jt
215
216#define JLE32(value, jt) \
217 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (value), 1, 0), \
218 jt
219
220/* Check hi > args.hi first, then do the GE checking */
221#define JGT64(lo, hi, jt) \
222 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (hi), 4, 0), \
223 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \
224 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
225 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (lo), 0, 2), \
226 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
227 jt, \
228 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
229
230#define JLE64(lo, hi, jt) \
231 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (hi), 6, 0), \
232 BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 3), \
233 BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \
234 BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (lo), 2, 0), \
235 BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \
236 jt, \
237 BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */
238
239#define LOAD_SYSCALL_NR \
240 BPF_STMT(BPF_LD+BPF_W+BPF_ABS, \
241 offsetof(struct seccomp_data, nr))
242
243#endif /* __BPF_HELPER_H__ */