1 /*
2 * Linux Socket Filter Data Structures
3 */
4
5 #ifndef __LINUX_FILTER_H__
6 #define __LINUX_FILTER_H__
7
8 #include <linux/compiler.h>
9 #include <linux/types.h>
10
11 #ifdef __KERNEL__
12 #include <linux/atomic.h>
13 #endif
14
15 /*
16 * Current version of the filter code architecture.
17 */
18 #define BPF_MAJOR_VERSION 1
19 #define BPF_MINOR_VERSION 1
20
21 /*
22 * Try and keep these values and structures similar to BSD, especially
23 * the BPF code definitions which need to match so you can share filters
24 */
25
26 struct sock_filter { /* Filter block */
27 __u16 code; /* Actual filter code */
28 __u8 jt; /* Jump true */
29 __u8 jf; /* Jump false */
30 __u32 k; /* Generic multiuse field */
31 };
32
33 struct sock_fprog { /* Required for SO_ATTACH_FILTER. */
34 unsigned short len; /* Number of filter blocks */
35 struct sock_filter __user *filter;
36 };
37
38 /*
39 * Instruction classes
40 */
41
42 #define BPF_CLASS(code) ((code) & 0x07)
43 #define BPF_LD 0x00
44 #define BPF_LDX 0x01
45 #define BPF_ST 0x02
46 #define BPF_STX 0x03
47 #define BPF_ALU 0x04
48 #define BPF_JMP 0x05
49 #define BPF_RET 0x06
50 #define BPF_MISC 0x07
51
52 /* ld/ldx fields */
53 #define BPF_SIZE(code) ((code) & 0x18)
54 #define BPF_W 0x00
55 #define BPF_H 0x08
56 #define BPF_B 0x10
57 #define BPF_MODE(code) ((code) & 0xe0)
58 #define BPF_IMM 0x00
59 #define BPF_ABS 0x20
60 #define BPF_IND 0x40
61 #define BPF_MEM 0x60
62 #define BPF_LEN 0x80
63 #define BPF_MSH 0xa0
64
65 /* alu/jmp fields */
66 #define BPF_OP(code) ((code) & 0xf0)
67 #define BPF_ADD 0x00
68 #define BPF_SUB 0x10
69 #define BPF_MUL 0x20
70 #define BPF_DIV 0x30
71 #define BPF_OR 0x40
72 #define BPF_AND 0x50
73 #define BPF_LSH 0x60
74 #define BPF_RSH 0x70
75 #define BPF_NEG 0x80
76 #define BPF_JA 0x00
77 #define BPF_JEQ 0x10
78 #define BPF_JGT 0x20
79 #define BPF_JGE 0x30
80 #define BPF_JSET 0x40
81 #define BPF_SRC(code) ((code) & 0x08)
82 #define BPF_K 0x00
83 #define BPF_X 0x08
84
85 /* ret - BPF_K and BPF_X also apply */
86 #define BPF_RVAL(code) ((code) & 0x18)
87 #define BPF_A 0x10
88
89 /* misc */
90 #define BPF_MISCOP(code) ((code) & 0xf8)
91 #define BPF_TAX 0x00
92 #define BPF_TXA 0x80
93
94 #ifndef BPF_MAXINSNS
95 #define BPF_MAXINSNS 4096
96 #endif
97
98 /*
99 * Macros for filter block array initializers.
100 */
101 #ifndef BPF_STMT
102 #define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k }
103 #endif
104 #ifndef BPF_JUMP
105 #define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k }
106 #endif
107
108 /*
109 * Number of scratch memory words for: BPF_ST and BPF_STX
110 */
111 #define BPF_MEMWORDS 16
112
113 /* RATIONALE. Negative offsets are invalid in BPF.
114 We use them to reference ancillary data.
115 Unlike introduction new instructions, it does not break
116 existing compilers/optimizers.
117 */
118 #define SKF_AD_OFF (-0x1000)
119 #define SKF_AD_PROTOCOL 0
120 #define SKF_AD_PKTTYPE 4
121 #define SKF_AD_IFINDEX 8
122 #define SKF_AD_NLATTR 12
123 #define SKF_AD_NLATTR_NEST 16
124 #define SKF_AD_MARK 20
125 #define SKF_AD_QUEUE 24
126 #define SKF_AD_HATYPE 28
127 #define SKF_AD_RXHASH 32
128 #define SKF_AD_CPU 36
129 #define SKF_AD_MAX 40
130 #define SKF_NET_OFF (-0x100000)
131 #define SKF_LL_OFF (-0x200000)
132
133 #ifdef __KERNEL__
134
135 struct sk_buff;
136 struct sock;
137
138 struct sk_filter
139 {
140 atomic_t refcnt;
141 unsigned int len; /* Number of filter blocks */
142 unsigned int (*bpf_func)(const struct sk_buff *skb,
143 const struct sock_filter *filter);
144 struct rcu_head rcu;
145 struct sock_filter insns[0];
146 };
147
sk_filter_len(const struct sk_filter * fp)148 static inline unsigned int sk_filter_len(const struct sk_filter *fp)
149 {
150 return fp->len * sizeof(struct sock_filter) + sizeof(*fp);
151 }
152
153 extern int sk_filter(struct sock *sk, struct sk_buff *skb);
154 extern unsigned int sk_run_filter(const struct sk_buff *skb,
155 const struct sock_filter *filter);
156 extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
157 extern int sk_detach_filter(struct sock *sk);
158 extern int sk_chk_filter(struct sock_filter *filter, unsigned int flen);
159
160 #ifdef CONFIG_BPF_JIT
161 extern void bpf_jit_compile(struct sk_filter *fp);
162 extern void bpf_jit_free(struct sk_filter *fp);
163 #define SK_RUN_FILTER(FILTER, SKB) (*FILTER->bpf_func)(SKB, FILTER->insns)
164 #else
bpf_jit_compile(struct sk_filter * fp)165 static inline void bpf_jit_compile(struct sk_filter *fp)
166 {
167 }
bpf_jit_free(struct sk_filter * fp)168 static inline void bpf_jit_free(struct sk_filter *fp)
169 {
170 }
171 #define SK_RUN_FILTER(FILTER, SKB) sk_run_filter(SKB, FILTER->insns)
172 #endif
173
174 enum {
175 BPF_S_RET_K = 1,
176 BPF_S_RET_A,
177 BPF_S_ALU_ADD_K,
178 BPF_S_ALU_ADD_X,
179 BPF_S_ALU_SUB_K,
180 BPF_S_ALU_SUB_X,
181 BPF_S_ALU_MUL_K,
182 BPF_S_ALU_MUL_X,
183 BPF_S_ALU_DIV_X,
184 BPF_S_ALU_AND_K,
185 BPF_S_ALU_AND_X,
186 BPF_S_ALU_OR_K,
187 BPF_S_ALU_OR_X,
188 BPF_S_ALU_LSH_K,
189 BPF_S_ALU_LSH_X,
190 BPF_S_ALU_RSH_K,
191 BPF_S_ALU_RSH_X,
192 BPF_S_ALU_NEG,
193 BPF_S_LD_W_ABS,
194 BPF_S_LD_H_ABS,
195 BPF_S_LD_B_ABS,
196 BPF_S_LD_W_LEN,
197 BPF_S_LD_W_IND,
198 BPF_S_LD_H_IND,
199 BPF_S_LD_B_IND,
200 BPF_S_LD_IMM,
201 BPF_S_LDX_W_LEN,
202 BPF_S_LDX_B_MSH,
203 BPF_S_LDX_IMM,
204 BPF_S_MISC_TAX,
205 BPF_S_MISC_TXA,
206 BPF_S_ALU_DIV_K,
207 BPF_S_LD_MEM,
208 BPF_S_LDX_MEM,
209 BPF_S_ST,
210 BPF_S_STX,
211 BPF_S_JMP_JA,
212 BPF_S_JMP_JEQ_K,
213 BPF_S_JMP_JEQ_X,
214 BPF_S_JMP_JGE_K,
215 BPF_S_JMP_JGE_X,
216 BPF_S_JMP_JGT_K,
217 BPF_S_JMP_JGT_X,
218 BPF_S_JMP_JSET_K,
219 BPF_S_JMP_JSET_X,
220 /* Ancillary data */
221 BPF_S_ANC_PROTOCOL,
222 BPF_S_ANC_PKTTYPE,
223 BPF_S_ANC_IFINDEX,
224 BPF_S_ANC_NLATTR,
225 BPF_S_ANC_NLATTR_NEST,
226 BPF_S_ANC_MARK,
227 BPF_S_ANC_QUEUE,
228 BPF_S_ANC_HATYPE,
229 BPF_S_ANC_RXHASH,
230 BPF_S_ANC_CPU,
231 };
232
233 #endif /* __KERNEL__ */
234
235 #endif /* __LINUX_FILTER_H__ */
236