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 */
32 #define NF_VERDICT_FLAG_QUEUE_BYPASS 0x00008000
34 /* queue number (NF_QUEUE) or errno (NF_DROP) */
35 #define NF_VERDICT_QMASK 0xffff0000
36 #define NF_VERDICT_QBITS 16
38 #define NF_QUEUE_NR(x) ((((x) << 16) & NF_VERDICT_QMASK) | NF_QUEUE)
40 #define NF_DROP_ERR(x) (((-x) << 16) | NF_DROP)
42 /* only for userspace compatibility */
44 /* Generic cache responses from hook functions.
45 <= 0x2000 is used for protocol-flags. */
46 #define NFC_UNKNOWN 0x4000
47 #define NFC_ALTERED 0x8000
49 /* NF_VERDICT_BITS should be 8 now, but userspace might break if this changes */
50 #define NF_VERDICT_BITS 16
81 #ifdef CONFIG_NETFILTER
82 static inline int NF_DROP_GETERR(int verdict)
84 return -(verdict >> NF_VERDICT_QBITS);
87 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
88 const union nf_inet_addr *a2)
90 return a1->all[0] == a2->all[0] &&
91 a1->all[1] == a2->all[1] &&
92 a1->all[2] == a2->all[2] &&
93 a1->all[3] == a2->all[3];
96 extern void netfilter_init(void);
98 /* Largest hook number + 1 */
99 #define NF_MAX_HOOKS 8
103 typedef unsigned int nf_hookfn(unsigned int hooknum,
105 const struct net_device *in,
106 const struct net_device *out,
107 int (*okfn)(struct sk_buff *));
110 struct list_head list;
112 /* User fills in from here down. */
114 struct module *owner;
116 unsigned int hooknum;
117 /* Hooks are ordered in ascending priority. */
121 struct nf_sockopt_ops {
122 struct list_head list;
126 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
129 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
131 int (*compat_set)(struct sock *sk, int optval,
132 void __user *user, unsigned int len);
136 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
138 int (*compat_get)(struct sock *sk, int optval,
139 void __user *user, int *len);
141 /* Use the module struct to lock set/get code in place */
142 struct module *owner;
145 /* Function to register/unregister hook points. */
146 int nf_register_hook(struct nf_hook_ops *reg);
147 void nf_unregister_hook(struct nf_hook_ops *reg);
148 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
149 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
151 /* Functions to register get/setsockopt ranges (non-inclusive). You
152 need to check permissions yourself! */
153 int nf_register_sockopt(struct nf_sockopt_ops *reg);
154 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
157 /* Sysctl registration */
158 extern struct ctl_path nf_net_netfilter_sysctl_path[];
159 extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[];
160 #endif /* CONFIG_SYSCTL */
162 extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
164 int nf_hook_slow(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
165 struct net_device *indev, struct net_device *outdev,
166 int (*okfn)(struct sk_buff *), int thresh);
169 * nf_hook_thresh - call a netfilter hook
171 * Returns 1 if the hook has allowed the packet to pass. The function
172 * okfn must be invoked by the caller in this case. Any other return
173 * value indicates the packet has been consumed by the hook.
175 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
177 struct net_device *indev,
178 struct net_device *outdev,
179 int (*okfn)(struct sk_buff *), int thresh)
181 #ifndef CONFIG_NETFILTER_DEBUG
182 if (list_empty(&nf_hooks[pf][hook]))
185 return nf_hook_slow(pf, hook, skb, indev, outdev, okfn, thresh);
188 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
189 struct net_device *indev, struct net_device *outdev,
190 int (*okfn)(struct sk_buff *))
192 return nf_hook_thresh(pf, hook, skb, indev, outdev, okfn, INT_MIN);
195 /* Activate hook; either okfn or kfree_skb called, unless a hook
196 returns NF_STOLEN (in which case, it's up to the hook to deal with
199 Returns -ERRNO if packet dropped. Zero means queued, stolen or
204 > I don't want nf_hook to return anything because people might forget
205 > about async and trust the return value to mean "packet was ok".
208 Just document it clearly, then you can expect some sense from kernel
213 NF_HOOK_THRESH(uint8_t pf, unsigned int hook, struct sk_buff *skb,
214 struct net_device *in, struct net_device *out,
215 int (*okfn)(struct sk_buff *), int thresh)
217 int ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, thresh);
224 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct sk_buff *skb,
225 struct net_device *in, struct net_device *out,
226 int (*okfn)(struct sk_buff *), bool cond)
231 ((ret = nf_hook_thresh(pf, hook, skb, in, out, okfn, INT_MIN)) == 1))
237 NF_HOOK(uint8_t pf, unsigned int hook, struct sk_buff *skb,
238 struct net_device *in, struct net_device *out,
239 int (*okfn)(struct sk_buff *))
241 return NF_HOOK_THRESH(pf, hook, skb, in, out, okfn, INT_MIN);
244 /* Call setsockopt() */
245 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
247 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
250 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval,
251 char __user *opt, unsigned int len);
252 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval,
253 char __user *opt, int *len);
256 /* Call this before modifying an existing packet: ensures it is
257 modifiable and linear to the point you care about (writable_len).
258 Returns true or false. */
259 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
262 struct nf_queue_entry;
265 unsigned short family;
266 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
267 unsigned int dataoff, u_int8_t protocol);
268 __sum16 (*checksum_partial)(struct sk_buff *skb,
270 unsigned int dataoff,
273 int (*route)(struct dst_entry **dst, struct flowi *fl);
274 void (*saveroute)(const struct sk_buff *skb,
275 struct nf_queue_entry *entry);
276 int (*reroute)(struct sk_buff *skb,
277 const struct nf_queue_entry *entry);
281 extern const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO];
282 static inline const struct nf_afinfo *nf_get_afinfo(unsigned short family)
284 return rcu_dereference(nf_afinfo[family]);
287 static inline __sum16
288 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
289 u_int8_t protocol, unsigned short family)
291 const struct nf_afinfo *afinfo;
295 afinfo = nf_get_afinfo(family);
297 csum = afinfo->checksum(skb, hook, dataoff, protocol);
302 static inline __sum16
303 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
304 unsigned int dataoff, unsigned int len,
305 u_int8_t protocol, unsigned short family)
307 const struct nf_afinfo *afinfo;
311 afinfo = nf_get_afinfo(family);
313 csum = afinfo->checksum_partial(skb, hook, dataoff, len,
319 extern int nf_register_afinfo(const struct nf_afinfo *afinfo);
320 extern void nf_unregister_afinfo(const struct nf_afinfo *afinfo);
322 #include <net/flow.h>
323 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
326 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
328 #ifdef CONFIG_NF_NAT_NEEDED
329 void (*decodefn)(struct sk_buff *, struct flowi *);
331 if (family == AF_INET) {
333 decodefn = rcu_dereference(ip_nat_decode_session);
341 #ifdef CONFIG_PROC_FS
342 #include <linux/proc_fs.h>
343 extern struct proc_dir_entry *proc_net_netfilter;
346 #else /* !CONFIG_NETFILTER */
347 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
348 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
349 static inline int nf_hook_thresh(u_int8_t pf, unsigned int hook,
351 struct net_device *indev,
352 struct net_device *outdev,
353 int (*okfn)(struct sk_buff *), int thresh)
357 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct sk_buff *skb,
358 struct net_device *indev, struct net_device *outdev,
359 int (*okfn)(struct sk_buff *))
365 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
368 #endif /*CONFIG_NETFILTER*/
370 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
371 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *) __rcu;
372 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
373 extern void (*nf_ct_destroy)(struct nf_conntrack *) __rcu;
375 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
378 #endif /*__KERNEL__*/
379 #endif /*__LINUX_NETFILTER_H*/