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#include <linux/compat.h>
14#endif
15
16/*
17 * Current version of the filter code architecture.
18 */
19#define BPF_MAJOR_VERSION 1
20#define BPF_MINOR_VERSION 1
21
22/*
23 *	Try and keep these values and structures similar to BSD, especially
24 *	the BPF code definitions which need to match so you can share filters
25 */
26
27struct sock_filter {	/* Filter block */
28	__u16	code;   /* Actual filter code */
29	__u8	jt;	/* Jump true */
30	__u8	jf;	/* Jump false */
31	__u32	k;      /* Generic multiuse field */
32};
33
34struct sock_fprog {	/* Required for SO_ATTACH_FILTER. */
35	unsigned short		len;	/* Number of filter blocks */
36	struct sock_filter __user *filter;
37};
38
39/*
40 * Instruction classes
41 */
42
43#define BPF_CLASS(code) ((code) & 0x07)
44#define         BPF_LD          0x00
45#define         BPF_LDX         0x01
46#define         BPF_ST          0x02
47#define         BPF_STX         0x03
48#define         BPF_ALU         0x04
49#define         BPF_JMP         0x05
50#define         BPF_RET         0x06
51#define         BPF_MISC        0x07
52
53/* ld/ldx fields */
54#define BPF_SIZE(code)  ((code) & 0x18)
55#define         BPF_W           0x00
56#define         BPF_H           0x08
57#define         BPF_B           0x10
58#define BPF_MODE(code)  ((code) & 0xe0)
59#define         BPF_IMM         0x00
60#define         BPF_ABS         0x20
61#define         BPF_IND         0x40
62#define         BPF_MEM         0x60
63#define         BPF_LEN         0x80
64#define         BPF_MSH         0xa0
65
66/* alu/jmp fields */
67#define BPF_OP(code)    ((code) & 0xf0)
68#define         BPF_ADD         0x00
69#define         BPF_SUB         0x10
70#define         BPF_MUL         0x20
71#define         BPF_DIV         0x30
72#define         BPF_OR          0x40
73#define         BPF_AND         0x50
74#define         BPF_LSH         0x60
75#define         BPF_RSH         0x70
76#define         BPF_NEG         0x80
77#define         BPF_JA          0x00
78#define         BPF_JEQ         0x10
79#define         BPF_JGT         0x20
80#define         BPF_JGE         0x30
81#define         BPF_JSET        0x40
82#define BPF_SRC(code)   ((code) & 0x08)
83#define         BPF_K           0x00
84#define         BPF_X           0x08
85
86/* ret - BPF_K and BPF_X also apply */
87#define BPF_RVAL(code)  ((code) & 0x18)
88#define         BPF_A           0x10
89
90/* misc */
91#define BPF_MISCOP(code) ((code) & 0xf8)
92#define         BPF_TAX         0x00
93#define         BPF_TXA         0x80
94
95#ifndef BPF_MAXINSNS
96#define BPF_MAXINSNS 4096
97#endif
98
99/*
100 * Macros for filter block array initializers.
101 */
102#ifndef BPF_STMT
103#define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k }
104#endif
105#ifndef BPF_JUMP
106#define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k }
107#endif
108
109/*
110 * Number of scratch memory words for: BPF_ST and BPF_STX
111 */
112#define BPF_MEMWORDS 16
113
114/* RATIONALE. Negative offsets are invalid in BPF.
115   We use them to reference ancillary data.
116   Unlike introduction new instructions, it does not break
117   existing compilers/optimizers.
118 */
119#define SKF_AD_OFF    (-0x1000)
120#define SKF_AD_PROTOCOL 0
121#define SKF_AD_PKTTYPE 	4
122#define SKF_AD_IFINDEX 	8
123#define SKF_AD_NLATTR	12
124#define SKF_AD_NLATTR_NEST	16
125#define SKF_AD_MARK 	20
126#define SKF_AD_QUEUE	24
127#define SKF_AD_HATYPE	28
128#define SKF_AD_RXHASH	32
129#define SKF_AD_CPU	36
130#define SKF_AD_ALU_XOR_X	40
131#define SKF_AD_MAX	44
132#define SKF_NET_OFF   (-0x100000)
133#define SKF_LL_OFF    (-0x200000)
134
135#ifdef __KERNEL__
136
137#ifdef CONFIG_COMPAT
138/*
139 * A struct sock_filter is architecture independent.
140 */
141struct compat_sock_fprog {
142	u16		len;
143	compat_uptr_t	filter;		/* struct sock_filter * */
144};
145#endif
146
147struct sk_buff;
148struct sock;
149
150struct sk_filter
151{
152	atomic_t		refcnt;
153	unsigned int         	len;	/* Number of filter blocks */
154	unsigned int		(*bpf_func)(const struct sk_buff *skb,
155					    const struct sock_filter *filter);
156	struct rcu_head		rcu;
157	struct sock_filter     	insns[0];
158};
159
160static inline unsigned int sk_filter_len(const struct sk_filter *fp)
161{
162	return fp->len * sizeof(struct sock_filter) + sizeof(*fp);
163}
164
165extern int sk_filter(struct sock *sk, struct sk_buff *skb);
166extern unsigned int sk_run_filter(const struct sk_buff *skb,
167				  const struct sock_filter *filter);
168extern int sk_unattached_filter_create(struct sk_filter **pfp,
169				       struct sock_fprog *fprog);
170extern void sk_unattached_filter_destroy(struct sk_filter *fp);
171extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
172extern int sk_detach_filter(struct sock *sk);
173extern int sk_chk_filter(struct sock_filter *filter, unsigned int flen);
174
175#ifdef CONFIG_BPF_JIT
176extern void bpf_jit_compile(struct sk_filter *fp);
177extern void bpf_jit_free(struct sk_filter *fp);
178#define SK_RUN_FILTER(FILTER, SKB) (*FILTER->bpf_func)(SKB, FILTER->insns)
179#else
180static inline void bpf_jit_compile(struct sk_filter *fp)
181{
182}
183static inline void bpf_jit_free(struct sk_filter *fp)
184{
185}
186#define SK_RUN_FILTER(FILTER, SKB) sk_run_filter(SKB, FILTER->insns)
187#endif
188
189enum {
190	BPF_S_RET_K = 1,
191	BPF_S_RET_A,
192	BPF_S_ALU_ADD_K,
193	BPF_S_ALU_ADD_X,
194	BPF_S_ALU_SUB_K,
195	BPF_S_ALU_SUB_X,
196	BPF_S_ALU_MUL_K,
197	BPF_S_ALU_MUL_X,
198	BPF_S_ALU_DIV_X,
199	BPF_S_ALU_AND_K,
200	BPF_S_ALU_AND_X,
201	BPF_S_ALU_OR_K,
202	BPF_S_ALU_OR_X,
203	BPF_S_ALU_LSH_K,
204	BPF_S_ALU_LSH_X,
205	BPF_S_ALU_RSH_K,
206	BPF_S_ALU_RSH_X,
207	BPF_S_ALU_NEG,
208	BPF_S_LD_W_ABS,
209	BPF_S_LD_H_ABS,
210	BPF_S_LD_B_ABS,
211	BPF_S_LD_W_LEN,
212	BPF_S_LD_W_IND,
213	BPF_S_LD_H_IND,
214	BPF_S_LD_B_IND,
215	BPF_S_LD_IMM,
216	BPF_S_LDX_W_LEN,
217	BPF_S_LDX_B_MSH,
218	BPF_S_LDX_IMM,
219	BPF_S_MISC_TAX,
220	BPF_S_MISC_TXA,
221	BPF_S_ALU_DIV_K,
222	BPF_S_LD_MEM,
223	BPF_S_LDX_MEM,
224	BPF_S_ST,
225	BPF_S_STX,
226	BPF_S_JMP_JA,
227	BPF_S_JMP_JEQ_K,
228	BPF_S_JMP_JEQ_X,
229	BPF_S_JMP_JGE_K,
230	BPF_S_JMP_JGE_X,
231	BPF_S_JMP_JGT_K,
232	BPF_S_JMP_JGT_X,
233	BPF_S_JMP_JSET_K,
234	BPF_S_JMP_JSET_X,
235	/* Ancillary data */
236	BPF_S_ANC_PROTOCOL,
237	BPF_S_ANC_PKTTYPE,
238	BPF_S_ANC_IFINDEX,
239	BPF_S_ANC_NLATTR,
240	BPF_S_ANC_NLATTR_NEST,
241	BPF_S_ANC_MARK,
242	BPF_S_ANC_QUEUE,
243	BPF_S_ANC_HATYPE,
244	BPF_S_ANC_RXHASH,
245	BPF_S_ANC_CPU,
246	BPF_S_ANC_ALU_XOR_X,
247	BPF_S_ANC_SECCOMP_LD_W,
248};
249
250#endif /* __KERNEL__ */
251
252#endif /* __LINUX_FILTER_H__ */
253