Linux kernel mirror (for testing)
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linux
1#ifndef __LINUX_NETFILTER_H
2#define __LINUX_NETFILTER_H
3
4#include <linux/init.h>
5#include <linux/skbuff.h>
6#include <linux/net.h>
7#include <linux/if.h>
8#include <linux/in.h>
9#include <linux/in6.h>
10#include <linux/wait.h>
11#include <linux/list.h>
12#include <uapi/linux/netfilter.h>
13#ifdef CONFIG_NETFILTER
14static inline int NF_DROP_GETERR(int verdict)
15{
16 return -(verdict >> NF_VERDICT_QBITS);
17}
18
19static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
20 const union nf_inet_addr *a2)
21{
22 return a1->all[0] == a2->all[0] &&
23 a1->all[1] == a2->all[1] &&
24 a1->all[2] == a2->all[2] &&
25 a1->all[3] == a2->all[3];
26}
27
28static inline void nf_inet_addr_mask(const union nf_inet_addr *a1,
29 union nf_inet_addr *result,
30 const union nf_inet_addr *mask)
31{
32 result->all[0] = a1->all[0] & mask->all[0];
33 result->all[1] = a1->all[1] & mask->all[1];
34 result->all[2] = a1->all[2] & mask->all[2];
35 result->all[3] = a1->all[3] & mask->all[3];
36}
37
38int netfilter_init(void);
39
40/* Largest hook number + 1 */
41#define NF_MAX_HOOKS 8
42
43struct sk_buff;
44
45struct nf_hook_ops;
46typedef unsigned int nf_hookfn(const struct nf_hook_ops *ops,
47 struct sk_buff *skb,
48 const struct net_device *in,
49 const struct net_device *out,
50 int (*okfn)(struct sk_buff *));
51
52struct nf_hook_ops {
53 struct list_head list;
54
55 /* User fills in from here down. */
56 nf_hookfn *hook;
57 struct module *owner;
58 void *priv;
59 u_int8_t pf;
60 unsigned int hooknum;
61 /* Hooks are ordered in ascending priority. */
62 int priority;
63};
64
65struct nf_sockopt_ops {
66 struct list_head list;
67
68 u_int8_t pf;
69
70 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
71 int set_optmin;
72 int set_optmax;
73 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
74#ifdef CONFIG_COMPAT
75 int (*compat_set)(struct sock *sk, int optval,
76 void __user *user, unsigned int len);
77#endif
78 int get_optmin;
79 int get_optmax;
80 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
81#ifdef CONFIG_COMPAT
82 int (*compat_get)(struct sock *sk, int optval,
83 void __user *user, int *len);
84#endif
85 /* Use the module struct to lock set/get code in place */
86 struct module *owner;
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);
92int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
93void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
94
95/* Functions to register get/setsockopt ranges (non-inclusive). You
96 need to check permissions yourself! */
97int nf_register_sockopt(struct nf_sockopt_ops *reg);
98void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
99
100extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
101
102#if defined(CONFIG_JUMP_LABEL)
103#include <linux/static_key.h>
104extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
105static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
106{
107 if (__builtin_constant_p(pf) &&
108 __builtin_constant_p(hook))
109 return static_key_false(&nf_hooks_needed[pf][hook]);
110
111 return !list_empty(&nf_hooks[pf][hook]);
112}
113#else
114static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook)
115{
116 return !list_empty(&nf_hooks[pf][hook]);
117}
118#endif
119
120int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
121 struct net_device *indev, struct net_device *outdev,
122 int (*okfn)(struct sk_buff *), int thresh);
123
124/**
125 * nf_hook_thresh - call a netfilter hook
126 *
127 * Returns 1 if the hook has allowed the packet to pass. The function
128 * okfn must be invoked by the caller in this case. Any other return
129 * value indicates the packet has been consumed by the hook.
130 */
131static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
132 struct sk_buff *skb,
133 struct net_device *indev,
134 struct net_device *outdev,
135 int (*okfn)(struct sk_buff *), int thresh)
136{
137 if (nf_hooks_active(pf, hook))
138 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
139 return 1;
140}
141
142static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
143 struct net_device *indev, struct net_device *outdev,
144 int (*okfn)(struct sk_buff *))
145{
146 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN);
147}
148
149/* Activate hook; either okfn or kfree_skb called, unless a hook
150 returns NF_STOLEN (in which case, it's up to the hook to deal with
151 the consequences).
152
153 Returns -ERRNO if packet dropped. Zero means queued, stolen or
154 accepted.
155*/
156
157/* RR:
158 > I don't want nf_hook to return anything because people might forget
159 > about async and trust the return value to mean "packet was ok".
160
161 AK:
162 Just document it clearly, then you can expect some sense from kernel
163 coders :)
164*/
165
166static inline int
167NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb,
168 struct net_device *in, struct net_device *out,
169 int (*okfn)(struct sk_buff *), int thresh)
170{
171 int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh);
172 if (ret == 1)
173 ret = okfn(skb);
174 return ret;
175}
176
177static inline int
178NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb,
179 struct net_device *in, struct net_device *out,
180 int (*okfn)(struct sk_buff *), bool cond)
181{
182 int ret;
183
184 if (!cond ||
185 ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1))
186 ret = okfn(skb);
187 return ret;
188}
189
190static inline int
191NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb,
192 struct net_device *in, struct net_device *out,
193 int (*okfn)(struct sk_buff *))
194{
195 return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN);
196}
197
198/* Call setsockopt() */
199int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
200 unsigned int len);
201int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
202 int *len);
203#ifdef CONFIG_COMPAT
204int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
205 char __user *opt, unsigned int len);
206int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
207 char __user *opt, int *len);
208#endif
209
210/* Call this before modifying an existing packet: ensures it is
211 modifiable and linear to the point you care about (writable_len).
212 Returns true or false. */
213int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
214
215struct flowi;
216struct nf_queue_entry;
217
218struct nf_afinfo {
219 unsigned short family;
220 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
221 unsigned int dataoff, u_int8_t protocol);
222 __sum16 (*checksum_partial)(struct sk_buff *skb,
223 unsigned int hook,
224 unsigned int dataoff,
225 unsigned int len,
226 u_int8_t protocol);
227 int (*route)(struct net *net, struct dst_entry **dst,
228 struct flowi *fl, bool strict);
229 void (*saveroute)(const struct sk_buff *skb,
230 struct nf_queue_entry *entry);
231 int (*reroute)(struct sk_buff *skb,
232 const struct nf_queue_entry *entry);
233 int route_key_size;
234};
235
236extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
237static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
238{
239 return rcu_dereference(nf_afinfo[family]);
240}
241
242static inline __sum16
243nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
244 u_int8_t protocol, unsigned short family)
245{
246 const struct nf_afinfo *afinfo;
247 __sum16 csum = 0;
248
249 rcu_read_lock();
250 afinfo = nf_get_afinfo(family);
251 if (afinfo)
252 csum = afinfo->checksum(skb, hook, dataoff, protocol);
253 rcu_read_unlock();
254 return csum;
255}
256
257static inline __sum16
258nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
259 unsigned int dataoff, unsigned int len,
260 u_int8_t protocol, unsigned short family)
261{
262 const struct nf_afinfo *afinfo;
263 __sum16 csum = 0;
264
265 rcu_read_lock();
266 afinfo = nf_get_afinfo(family);
267 if (afinfo)
268 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
269 protocol);
270 rcu_read_unlock();
271 return csum;
272}
273
274int nf_register_afinfo(const struct nf_afinfo *afinfo);
275void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
276
277#include <net/flow.h>
278extern void (*nf_nat_decode_session_hook)(struct sk_buff *, struct flowi *);
279
280static inline void
281nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
282{
283#ifdef CONFIG_NF_NAT_NEEDED
284 void (*decodefn)(struct sk_buff *, struct flowi *);
285
286 rcu_read_lock();
287 decodefn = rcu_dereference(nf_nat_decode_session_hook);
288 if (decodefn)
289 decodefn(skb, fl);
290 rcu_read_unlock();
291#endif
292}
293
294#else /* !CONFIG_NETFILTER */
295#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
296#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
297static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
298 struct sk_buff *skb,
299 struct net_device *indev,
300 struct net_device *outdev,
301 int (*okfn)(struct sk_buff *), int thresh)
302{
303 return okfn(skb);
304}
305static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
306 struct net_device *indev, struct net_device *outdev,
307 int (*okfn)(struct sk_buff *))
308{
309 return 1;
310}
311struct flowi;
312static inline void
313nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
314{
315}
316#endif /*CONFIG_NETFILTER*/
317
318#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
319extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
320void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
321extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
322
323struct nf_conn;
324enum ip_conntrack_info;
325struct nlattr;
326
327struct nfq_ct_hook {
328 size_t (*build_size)(const struct nf_conn *ct);
329 int (*build)(struct sk_buff *skb, struct nf_conn *ct);
330 int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
331 int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
332 u32 portid, u32 report);
333 void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
334 enum ip_conntrack_info ctinfo, s32 off);
335};
336extern struct nfq_ct_hook __rcu *nfq_ct_hook;
337#else
338static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
339#endif
340
341#endif /*__LINUX_NETFILTER_H*/