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>
17 /* Responses from hook functions. */
24 #define NF_MAX_VERDICT NF_STOP
26 /* we overload the higher bits for encoding auxiliary data such as the queue
27 * number or errno values. Not nice, but better than additional function
29 #define NF_VERDICT_MASK 0x000000ff
31 /* extra verdict flags have mask 0x0000ff00 */
33 /* queue number (NF_QUEUE) or errno (NF_DROP) */
34 #define NF_VERDICT_QMASK 0xffff0000
35 #define NF_VERDICT_QBITS 16
37 #define NF_QUEUE_NR(x) ((((x) << 16) & NF_VERDICT_QMASK) | NF_QUEUE)
39 #define NF_DROP_ERR(x) (((-x) << 16) | NF_DROP)
41 /* only for userspace compatibility */
43 /* Generic cache responses from hook functions.
44 <= 0x2000 is used for protocol-flags. */
45 #define NFC_UNKNOWN 0x4000
46 #define NFC_ALTERED 0x8000
48 /* NF_VERDICT_BITS should be 8 now, but userspace might break if this changes */
49 #define NF_VERDICT_BITS 16
80 #ifdef CONFIG_NETFILTER
81 static inline int NF_DROP_GETERR(int verdict)
83 return -(verdict >> NF_VERDICT_QBITS);
86 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
87 const union nf_inet_addr *a2)
89 return a1->all[0] == a2->all[0] &&
90 a1->all[1] == a2->all[1] &&
91 a1->all[2] == a2->all[2] &&
92 a1->all[3] == a2->all[3];
95 extern void netfilter_init(void);
97 /* Largest hook number + 1 */
98 #define NF_MAX_HOOKS 8
102 typedef unsigned int nf_hookfn(unsigned int hooknum,
104 const struct net_device *in,
105 const struct net_device *out,
106 int (*okfn)(struct sk_buff *));
109 struct list_head list;
111 /* User fills in from here down. */
113 struct module *owner;
115 unsigned int hooknum;
116 /* Hooks are ordered in ascending priority. */
120 struct nf_sockopt_ops {
121 struct list_head list;
125 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
128 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
130 int (*compat_set)(struct sock *sk, int optval,
131 void __user *user, unsigned int len);
135 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
137 int (*compat_get)(struct sock *sk, int optval,
138 void __user *user, int *len);
140 /* Use the module struct to lock set/get code in place */
141 struct module *owner;
144 /* Function to register/unregister hook points. */
145 int nf_register_hook(struct nf_hook_ops *reg);
146 void nf_unregister_hook(struct nf_hook_ops *reg);
147 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
148 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
150 /* Functions to register get/setsockopt ranges (non-inclusive). You
151 need to check permissions yourself! */
152 int nf_register_sockopt(struct nf_sockopt_ops *reg);
153 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
156 /* Sysctl registration */
157 extern struct ctl_path nf_net_netfilter_sysctl_path[];
158 extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
159 #endif /* CONFIG_SYSCTL */
161 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
163 int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
164 struct net_device *indev, struct net_device *outdev,
165 int (*okfn)(struct sk_buff *), int thresh);
168 * nf_hook_thresh - call a netfilter hook
170 * Returns 1 if the hook has allowed the packet to pass. The function
171 * okfn must be invoked by the caller in this case. Any other return
172 * value indicates the packet has been consumed by the hook.
174 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
176 struct net_device *indev,
177 struct net_device *outdev,
178 int (*okfn)(struct sk_buff *), int thresh)
180 #ifndef CONFIG_NETFILTER_DEBUG
181 if (list_empty(&nf_hooks[pf][hook]))
184 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
187 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
188 struct net_device *indev, struct net_device *outdev,
189 int (*okfn)(struct sk_buff *))
191 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN);
194 /* Activate hook; either okfn or kfree_skb called, unless a hook
195 returns NF_STOLEN (in which case, it's up to the hook to deal with
198 Returns -ERRNO if packet dropped. Zero means queued, stolen or
203 > I don't want nf_hook to return anything because people might forget
204 > about async and trust the return value to mean "packet was ok".
207 Just document it clearly, then you can expect some sense from kernel
212 NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb,
213 struct net_device *in, struct net_device *out,
214 int (*okfn)(struct sk_buff *), int thresh)
216 int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh);
223 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb,
224 struct net_device *in, struct net_device *out,
225 int (*okfn)(struct sk_buff *), bool cond)
230 ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1))
236 NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb,
237 struct net_device *in, struct net_device *out,
238 int (*okfn)(struct sk_buff *))
240 return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN);
243 /* Call setsockopt() */
244 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
246 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
249 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
250 char __user *opt, unsigned int len);
251 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
252 char __user *opt, int *len);
255 /* Call this before modifying an existing packet: ensures it is
256 modifiable and linear to the point you care about (writable_len).
257 Returns true or false. */
258 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
261 struct nf_queue_entry;
264 unsigned short family;
265 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
266 unsigned int dataoff, u_int8_t protocol);
267 __sum16 (*checksum_partial)(struct sk_buff *skb,
269 unsigned int dataoff,
272 int (*route)(struct dst_entry **dst, struct flowi *fl);
273 void (*saveroute)(const struct sk_buff *skb,
274 struct nf_queue_entry *entry);
275 int (*reroute)(struct sk_buff *skb,
276 const struct nf_queue_entry *entry);
280 extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
281 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
283 return rcu_dereference(nf_afinfo[family]);
286 static inline __sum16
287 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
288 u_int8_t protocol, unsigned short family)
290 const struct nf_afinfo *afinfo;
294 afinfo = nf_get_afinfo(family);
296 csum = afinfo->checksum(skb, hook, dataoff, protocol);
301 static inline __sum16
302 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
303 unsigned int dataoff, unsigned int len,
304 u_int8_t protocol, unsigned short family)
306 const struct nf_afinfo *afinfo;
310 afinfo = nf_get_afinfo(family);
312 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
318 extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
319 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
321 #include <net/flow.h>
322 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
325 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
327 #ifdef CONFIG_NF_NAT_NEEDED
328 void (*decodefn)(struct sk_buff *, struct flowi *);
330 if (family == AF_INET) {
332 decodefn = rcu_dereference(ip_nat_decode_session);
340 #ifdef CONFIG_PROC_FS
341 #include <linux/proc_fs.h>
342 extern struct proc_dir_entry *proc_net_netfilter;
345 #else /* !CONFIG_NETFILTER */
346 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
347 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
348 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
350 struct net_device *indev,
351 struct net_device *outdev,
352 int (*okfn)(struct sk_buff *), int thresh)
356 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
357 struct net_device *indev, struct net_device *outdev,
358 int (*okfn)(struct sk_buff *))
364 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
367 #endif /*CONFIG_NETFILTER*/
369 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
370 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *) __rcu;
371 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
372 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
374 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
377 #endif /*__KERNEL__*/
378 #endif /*__LINUX_NETFILTER_H*/