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
14 /* Responses from hook functions. */
15 #define NF_DROP 0
16 #define NF_ACCEPT 1
17 #define NF_STOLEN 2
18 #define NF_QUEUE 3
19 #define NF_REPEAT 4
20 #define NF_MAX_VERDICT NF_REPEAT
21
22 /* Generic cache responses from hook functions.
23 <= 0x2000 is used for protocol-flags. */
24 #define NFC_UNKNOWN 0x4000
25 #define NFC_ALTERED 0x8000
26
27 #ifdef __KERNEL__
28 #include <linux/config.h>
29 #ifdef CONFIG_NETFILTER
30
31 extern void netfilter_init(void);
32
33 /* Largest hook number + 1 */
34 #define NF_MAX_HOOKS 8
35
36 struct sk_buff;
37 struct net_device;
38
39 typedef unsigned int nf_hookfn(unsigned int hooknum,
40 struct sk_buff **skb,
41 const struct net_device *in,
42 const struct net_device *out,
43 int (*okfn)(struct sk_buff *));
44
45 struct nf_hook_ops
46 {
47 struct list_head list;
48
49 /* User fills in from here down. */
50 nf_hookfn *hook;
51 int pf;
52 int hooknum;
53 /* Hooks are ordered in ascending priority. */
54 int priority;
55 };
56
57 struct nf_sockopt_ops
58 {
59 struct list_head list;
60
61 int pf;
62
63 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
64 int set_optmin;
65 int set_optmax;
66 int (*set)(struct sock *sk, int optval, void *user, unsigned int len);
67
68 int get_optmin;
69 int get_optmax;
70 int (*get)(struct sock *sk, int optval, void *user, int *len);
71
72 /* Number of users inside set() or get(). */
73 unsigned int use;
74 struct task_struct *cleanup_task;
75 };
76
77 /* Each queued (to userspace) skbuff has one of these. */
78 struct nf_info
79 {
80 /* The ops struct which sent us to userspace. */
81 struct nf_hook_ops *elem;
82
83 /* If we're sent to userspace, this keeps housekeeping info */
84 int pf;
85 unsigned int hook;
86 struct net_device *indev, *outdev;
87 int (*okfn)(struct sk_buff *);
88 };
89
90 /* Function to register/unregister hook points. */
91 int nf_register_hook(struct nf_hook_ops *reg);
92 void nf_unregister_hook(struct nf_hook_ops *reg);
93
94 /* Functions to register get/setsockopt ranges (non-inclusive). You
95 need to check permissions yourself! */
96 int nf_register_sockopt(struct nf_sockopt_ops *reg);
97 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
98
99 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
100
101 /* Activate hook; either okfn or kfree_skb called, unless a hook
102 returns NF_STOLEN (in which case, it's up to the hook to deal with
103 the consequences).
104
105 Returns -ERRNO if packet dropped. Zero means queued, stolen or
106 accepted.
107 */
108
109 /* RR:
110 > I don't want nf_hook to return anything because people might forget
111 > about async and trust the return value to mean "packet was ok".
112
113 AK:
114 Just document it clearly, then you can expect some sense from kernel
115 coders :)
116 */
117
118 /* This is gross, but inline doesn't cut it for avoiding the function
119 call in fast path: gcc doesn't inline (needs value tracking?). --RR */
120 #ifdef CONFIG_NETFILTER_DEBUG
121 #define NF_HOOK nf_hook_slow
122 #else
123 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
124 (list_empty(&nf_hooks[(pf)][(hook)]) \
125 ? (okfn)(skb) \
126 : nf_hook_slow((pf), (hook), (skb), (indev), (outdev), (okfn)))
127 #endif
128
129 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff *skb,
130 struct net_device *indev, struct net_device *outdev,
131 int (*okfn)(struct sk_buff *));
132
133 /* Call setsockopt() */
134 int nf_setsockopt(struct sock *sk, int pf, int optval, char *opt,
135 int len);
136 int nf_getsockopt(struct sock *sk, int pf, int optval, char *opt,
137 int *len);
138
139 /* Packet queuing */
140 typedef int (*nf_queue_outfn_t)(struct sk_buff *skb,
141 struct nf_info *info, void *data);
142 extern int nf_register_queue_handler(int pf,
143 nf_queue_outfn_t outfn, void *data);
144 extern int nf_unregister_queue_handler(int pf);
145 extern void nf_reinject(struct sk_buff *skb,
146 struct nf_info *info,
147 unsigned int verdict);
148
149 extern inline struct ipt_target *
150 ipt_find_target_lock(const char *name, int *error, struct semaphore *mutex);
151 extern inline struct ip6t_target *
152 ip6t_find_target_lock(const char *name, int *error, struct semaphore *mutex);
153 extern inline struct arpt_target *
154 arpt_find_target_lock(const char *name, int *error, struct semaphore *mutex);
155 extern void (*ip_ct_attach)(struct sk_buff *, struct nf_ct_info *);
156 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
157
158 #ifdef CONFIG_NETFILTER_DEBUG
159 extern void nf_dump_skb(int pf, struct sk_buff *skb);
160 #endif
161
162 /* FIXME: Before cache is ever used, this must be implemented for real. */
163 extern void nf_invalidate_cache(int pf);
164
165 #else /* !CONFIG_NETFILTER */
166 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
nf_ct_attach(struct sk_buff * new,struct sk_buff * skb)167 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
168 #endif /*CONFIG_NETFILTER*/
169
170 /* From arch/i386/kernel/smp.c:
171 *
172 * Why isn't this somewhere standard ??
173 *
174 * Maybe because this procedure is horribly buggy, and does
175 * not deserve to live. Think about signedness issues for five
176 * seconds to see why. - Linus
177 */
178
179 /* Two signed, return a signed. */
180 #define SMAX(a,b) ((ssize_t)(a)>(ssize_t)(b) ? (ssize_t)(a) : (ssize_t)(b))
181 #define SMIN(a,b) ((ssize_t)(a)<(ssize_t)(b) ? (ssize_t)(a) : (ssize_t)(b))
182
183 /* Two unsigned, return an unsigned. */
184 #define UMAX(a,b) ((size_t)(a)>(size_t)(b) ? (size_t)(a) : (size_t)(b))
185 #define UMIN(a,b) ((size_t)(a)<(size_t)(b) ? (size_t)(a) : (size_t)(b))
186
187 /* Two unsigned, return a signed. */
188 #define SUMAX(a,b) ((size_t)(a)>(size_t)(b) ? (ssize_t)(a) : (ssize_t)(b))
189 #define SUMIN(a,b) ((size_t)(a)<(size_t)(b) ? (ssize_t)(a) : (ssize_t)(b))
190 #endif /*__KERNEL__*/
191
192 #endif /*__LINUX_NETFILTER_H*/
193