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