1 #ifndef __LINUX_NETFILTER_H
2 #define __LINUX_NETFILTER_H
5 #include <linux/init.h>
6 #include <linux/skbuff.h>
10 #include <linux/in6.h>
11 #include <linux/wait.h>
12 #include <linux/list.h>
14 #include <linux/types.h>
15 #include <linux/compiler.h>
16 #include <linux/sysctl.h>
18 /* Responses from hook functions. */
25 #define NF_MAX_VERDICT NF_STOP
27 /* we overload the higher bits for encoding auxiliary data such as the queue
28 * number or errno values. Not nice, but better than additional function
30 #define NF_VERDICT_MASK 0x000000ff
32 /* extra verdict flags have mask 0x0000ff00 */
33 #define NF_VERDICT_FLAG_QUEUE_BYPASS 0x00008000
35 /* queue number (NF_QUEUE) or errno (NF_DROP) */
36 #define NF_VERDICT_QMASK 0xffff0000
37 #define NF_VERDICT_QBITS 16
39 #define NF_QUEUE_NR(x) ((((x) << 16) & NF_VERDICT_QMASK) | NF_QUEUE)
41 #define NF_DROP_ERR(x) (((-x) << 16) | NF_DROP)
43 /* only for userspace compatibility */
45 /* Generic cache responses from hook functions.
46 <= 0x2000 is used for protocol-flags. */
47 #define NFC_UNKNOWN 0x4000
48 #define NFC_ALTERED 0x8000
50 /* NF_VERDICT_BITS should be 8 now, but userspace might break if this changes */
51 #define NF_VERDICT_BITS 16
82 #ifdef CONFIG_NETFILTER
83 static inline int NF_DROP_GETERR(int verdict)
85 return -(verdict >> NF_VERDICT_QBITS);
88 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
89 const union nf_inet_addr *a2)
91 return a1->all[0] == a2->all[0] &&
92 a1->all[1] == a2->all[1] &&
93 a1->all[2] == a2->all[2] &&
94 a1->all[3] == a2->all[3];
97 extern void netfilter_init(void);
99 /* Largest hook number + 1 */
100 #define NF_MAX_HOOKS 8
104 typedef unsigned int nf_hookfn(unsigned int hooknum,
106 const struct net_device *in,
107 const struct net_device *out,
108 int (*okfn)(struct sk_buff *));
111 struct list_head list;
113 /* User fills in from here down. */
115 struct module *owner;
117 unsigned int hooknum;
118 /* Hooks are ordered in ascending priority. */
122 struct nf_sockopt_ops {
123 struct list_head list;
127 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
130 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
132 int (*compat_set)(struct sock *sk, int optval,
133 void __user *user, unsigned int len);
137 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
139 int (*compat_get)(struct sock *sk, int optval,
140 void __user *user, int *len);
142 /* Use the module struct to lock set/get code in place */
143 struct module *owner;
146 /* Function to register/unregister hook points. */
147 int nf_register_hook(struct nf_hook_ops *reg);
148 void nf_unregister_hook(struct nf_hook_ops *reg);
149 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
150 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
152 /* Functions to register get/setsockopt ranges (non-inclusive). You
153 need to check permissions yourself! */
154 int nf_register_sockopt(struct nf_sockopt_ops *reg);
155 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
158 /* Sysctl registration */
159 extern struct ctl_path nf_net_netfilter_sysctl_path[];
160 extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
161 #endif /* CONFIG_SYSCTL */
163 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
165 int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
166 struct net_device *indev, struct net_device *outdev,
167 int (*okfn)(struct sk_buff *), int thresh);
170 * nf_hook_thresh - call a netfilter hook
172 * Returns 1 if the hook has allowed the packet to pass. The function
173 * okfn must be invoked by the caller in this case. Any other return
174 * value indicates the packet has been consumed by the hook.
176 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
178 struct net_device *indev,
179 struct net_device *outdev,
180 int (*okfn)(struct sk_buff *), int thresh)
182 #ifndef CONFIG_NETFILTER_DEBUG
183 if (list_empty(&nf_hooks[pf][hook]))
186 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
189 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
190 struct net_device *indev, struct net_device *outdev,
191 int (*okfn)(struct sk_buff *))
193 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN);
196 /* Activate hook; either okfn or kfree_skb called, unless a hook
197 returns NF_STOLEN (in which case, it's up to the hook to deal with
200 Returns -ERRNO if packet dropped. Zero means queued, stolen or
205 > I don't want nf_hook to return anything because people might forget
206 > about async and trust the return value to mean "packet was ok".
209 Just document it clearly, then you can expect some sense from kernel
214 NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb,
215 struct net_device *in, struct net_device *out,
216 int (*okfn)(struct sk_buff *), int thresh)
218 int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh);
225 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb,
226 struct net_device *in, struct net_device *out,
227 int (*okfn)(struct sk_buff *), bool cond)
232 ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1))
238 NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb,
239 struct net_device *in, struct net_device *out,
240 int (*okfn)(struct sk_buff *))
242 return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN);
245 /* Call setsockopt() */
246 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
248 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
251 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
252 char __user *opt, unsigned int len);
253 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
254 char __user *opt, int *len);
257 /* Call this before modifying an existing packet: ensures it is
258 modifiable and linear to the point you care about (writable_len).
259 Returns true or false. */
260 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
263 struct nf_queue_entry;
266 unsigned short family;
267 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
268 unsigned int dataoff, u_int8_t protocol);
269 __sum16 (*checksum_partial)(struct sk_buff *skb,
271 unsigned int dataoff,
274 int (*route)(struct net *net, struct dst_entry **dst,
275 struct flowi *fl, bool strict);
276 void (*saveroute)(const struct sk_buff *skb,
277 struct nf_queue_entry *entry);
278 int (*reroute)(struct sk_buff *skb,
279 const struct nf_queue_entry *entry);
283 extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
284 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
286 return rcu_dereference(nf_afinfo[family]);
289 static inline __sum16
290 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
291 u_int8_t protocol, unsigned short family)
293 const struct nf_afinfo *afinfo;
297 afinfo = nf_get_afinfo(family);
299 csum = afinfo->checksum(skb, hook, dataoff, protocol);
304 static inline __sum16
305 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
306 unsigned int dataoff, unsigned int len,
307 u_int8_t protocol, unsigned short family)
309 const struct nf_afinfo *afinfo;
313 afinfo = nf_get_afinfo(family);
315 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
321 extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
322 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
324 #include <net/flow.h>
325 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
328 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
330 #ifdef CONFIG_NF_NAT_NEEDED
331 void (*decodefn)(struct sk_buff *, struct flowi *);
333 if (family == AF_INET) {
335 decodefn = rcu_dereference(ip_nat_decode_session);
343 #ifdef CONFIG_PROC_FS
344 #include <linux/proc_fs.h>
345 extern struct proc_dir_entry *proc_net_netfilter;
348 #else /* !CONFIG_NETFILTER */
349 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
350 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
351 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
353 struct net_device *indev,
354 struct net_device *outdev,
355 int (*okfn)(struct sk_buff *), int thresh)
359 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
360 struct net_device *indev, struct net_device *outdev,
361 int (*okfn)(struct sk_buff *))
367 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
370 #endif /*CONFIG_NETFILTER*/
372 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
373 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *) __rcu;
374 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
375 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
377 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
380 #endif /*__KERNEL__*/
381 #endif /*__LINUX_NETFILTER_H*/