1 #ifndef __LINUX_NETFILTER_H
2 #define __LINUX_NETFILTER_H
3
4 #ifdef __KERNEL__
5 #include <linux/init.h>
6 #include <linux/types.h>
7 #include <linux/skbuff.h>
8 #include <linux/net.h>
9 #include <linux/if.h>
10 #include <linux/wait.h>
11 #include <linux/list.h>
12 #endif
13 #include <linux/compiler.h>
14
15 /* Responses from hook functions. */
16 #define NF_DROP 0
17 #define NF_ACCEPT 1
18 #define NF_STOLEN 2
19 #define NF_QUEUE 3
20 #define NF_REPEAT 4
21 #define NF_MAX_VERDICT NF_REPEAT
22
23 /* Generic cache responses from hook functions.
24 <= 0x2000 is used for protocol-flags. */
25 #define NFC_UNKNOWN 0x4000
26 #define NFC_ALTERED 0x8000
27
28 #ifdef __KERNEL__
29 #include <linux/config.h>
30 #ifdef CONFIG_NETFILTER
31
32 extern void netfilter_init(void);
33
34 /* Largest hook number + 1 */
35 #define NF_MAX_HOOKS 8
36
37 struct sk_buff;
38 struct net_device;
39
40 typedef unsigned int nf_hookfn(unsigned int hooknum,
41 struct sk_buff **skb,
42 const struct net_device *in,
43 const struct net_device *out,
44 int (*okfn)(struct sk_buff *));
45
46 struct nf_hook_ops
47 {
48 struct list_head list;
49
50 /* User fills in from here down. */
51 nf_hookfn *hook;
52 struct module *owner;
53 int pf;
54 int hooknum;
55 /* Hooks are ordered in ascending priority. */
56 int priority;
57 };
58
59 struct nf_sockopt_ops
60 {
61 struct list_head list;
62
63 int pf;
64
65 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
66 int set_optmin;
67 int set_optmax;
68 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
69
70 int get_optmin;
71 int get_optmax;
72 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
73
74 /* Number of users inside set() or get(). */
75 unsigned int use;
76 struct task_struct *cleanup_task;
77 };
78
79 /* Each queued (to userspace) skbuff has one of these. */
80 struct nf_info
81 {
82 /* The ops struct which sent us to userspace. */
83 struct nf_hook_ops *elem;
84
85 /* If we're sent to userspace, this keeps housekeeping info */
86 int pf;
87 unsigned int hook;
88 struct net_device *indev, *outdev;
89 int (*okfn)(struct sk_buff *);
90 };
91
92 /* Function to register/unregister hook points. */
93 int nf_register_hook(struct nf_hook_ops *reg);
94 void nf_unregister_hook(struct nf_hook_ops *reg);
95
96 /* Functions to register get/setsockopt ranges (non-inclusive). You
97 need to check permissions yourself! */
98 int nf_register_sockopt(struct nf_sockopt_ops *reg);
99 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
100
101 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
102
103 typedef void nf_logfn(unsigned int hooknum,
104 const struct sk_buff *skb,
105 const struct net_device *in,
106 const struct net_device *out,
107 const char *prefix);
108
109 /* Function to register/unregister log function. */
110 int nf_log_register(int pf, nf_logfn *logfn);
111 void nf_log_unregister(int pf, nf_logfn *logfn);
112
113 /* Calls the registered backend logging function */
114 void nf_log_packet(int pf,
115 unsigned int hooknum,
116 const struct sk_buff *skb,
117 const struct net_device *in,
118 const struct net_device *out,
119 const char *fmt, ...);
120
121 /* Activate hook; either okfn or kfree_skb called, unless a hook
122 returns NF_STOLEN (in which case, it's up to the hook to deal with
123 the consequences).
124
125 Returns -ERRNO if packet dropped. Zero means queued, stolen or
126 accepted.
127 */
128
129 /* RR:
130 > I don't want nf_hook to return anything because people might forget
131 > about async and trust the return value to mean "packet was ok".
132
133 AK:
134 Just document it clearly, then you can expect some sense from kernel
135 coders :)
136 */
137
138 /* This is gross, but inline doesn't cut it for avoiding the function
139 call in fast path: gcc doesn't inline (needs value tracking?). --RR */
140 #ifdef CONFIG_NETFILTER_DEBUG
141 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
142 nf_hook_slow((pf), (hook), (skb), (indev), (outdev), (okfn), INT_MIN)
143 #define NF_HOOK_THRESH nf_hook_slow
144 #else
145 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
146 (list_empty(&nf_hooks[(pf)][(hook)]) \
147 ? (okfn)(skb) \
148 : nf_hook_slow((pf), (hook), (skb), (indev), (outdev), (okfn), INT_MIN))
149 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
150 (list_empty(&nf_hooks[(pf)][(hook)]) \
151 ? (okfn)(skb) \
152 : nf_hook_slow((pf), (hook), (skb), (indev), (outdev), (okfn), (thresh)))
153 #endif
154
155 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb,
156 struct net_device *indev, struct net_device *outdev,
157 int (*okfn)(struct sk_buff *), int thresh);
158
159 /* Call setsockopt() */
160 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt,
161 int len);
162 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
163 int *len);
164
165 /* Packet queuing */
166 typedef int (*nf_queue_outfn_t)(struct sk_buff *skb,
167 struct nf_info *info, void *data);
168 extern int nf_register_queue_handler(int pf,
169 nf_queue_outfn_t outfn, void *data);
170 extern int nf_unregister_queue_handler(int pf);
171 extern void nf_reinject(struct sk_buff *skb,
172 struct nf_info *info,
173 unsigned int verdict);
174
175 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
176 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
177
178 /* FIXME: Before cache is ever used, this must be implemented for real. */
179 extern void nf_invalidate_cache(int pf);
180
181 #else /* !CONFIG_NETFILTER */
182 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
183 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
184 #endif /*CONFIG_NETFILTER*/
185
186 #endif /*__KERNEL__*/
187 #endif /*__LINUX_NETFILTER_H*/
188
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