1 #ifndef __LINUX_NETFILTER_H
2 #define __LINUX_NETFILTER_H
5 #include <linux/init.h>
6 #include <linux/types.h>
7 #include <linux/skbuff.h>
10 #include <linux/wait.h>
11 #include <linux/list.h>
13 #include <linux/compiler.h>
15 /* Responses from hook functions. */
22 #define NF_MAX_VERDICT NF_STOP
24 /* we overload the higher bits for encoding auxiliary data such as the queue
25 * number. Not nice, but better than additional function arguments. */
26 #define NF_VERDICT_MASK 0x0000ffff
27 #define NF_VERDICT_BITS 16
29 #define NF_VERDICT_QMASK 0xffff0000
30 #define NF_VERDICT_QBITS 16
32 #define NF_QUEUE_NR(x) (((x << NF_VERDICT_QBITS) & NF_VERDICT_QMASK) | NF_QUEUE)
34 /* only for userspace compatibility */
36 /* Generic cache responses from hook functions.
37 <= 0x2000 is used for protocol-flags. */
38 #define NFC_UNKNOWN 0x4000
39 #define NFC_ALTERED 0x8000
43 #ifdef CONFIG_NETFILTER
45 extern void netfilter_init(void);
47 /* Largest hook number + 1 */
48 #define NF_MAX_HOOKS 8
53 typedef unsigned int nf_hookfn(unsigned int hooknum,
55 const struct net_device *in,
56 const struct net_device *out,
57 int (*okfn)(struct sk_buff *));
61 struct list_head list;
63 /* User fills in from here down. */
68 /* Hooks are ordered in ascending priority. */
74 struct list_head list;
78 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
81 int (*set)(struct sock *sk, int optval, void __user *user, unsigned int len);
82 int (*compat_set)(struct sock *sk, int optval,
83 void __user *user, unsigned int len);
87 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
88 int (*compat_get)(struct sock *sk, int optval,
89 void __user *user, int *len);
91 /* Use the module struct to lock set/get code in place */
95 /* Each queued (to userspace) skbuff has one of these. */
98 /* The ops struct which sent us to userspace. */
99 struct nf_hook_ops *elem;
101 /* If we're sent to userspace, this keeps housekeeping info */
104 struct net_device *indev, *outdev;
105 int (*okfn)(struct sk_buff *);
108 /* Function to register/unregister hook points. */
109 int nf_register_hook(struct nf_hook_ops *reg);
110 void nf_unregister_hook(struct nf_hook_ops *reg);
111 int nf_register_hooks(struct nf_hook_ops *reg, unsigned int n);
112 void nf_unregister_hooks(struct nf_hook_ops *reg, unsigned int n);
114 /* Functions to register get/setsockopt ranges (non-inclusive). You
115 need to check permissions yourself! */
116 int nf_register_sockopt(struct nf_sockopt_ops *reg);
117 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
120 /* Sysctl registration */
121 struct ctl_table_header *nf_register_sysctl_table(struct ctl_table *path,
122 struct ctl_table *table);
123 void nf_unregister_sysctl_table(struct ctl_table_header *header,
124 struct ctl_table *table);
125 extern struct ctl_table nf_net_netfilter_sysctl_path[];
126 extern struct ctl_table nf_net_ipv4_netfilter_sysctl_path[];
127 #endif /* CONFIG_SYSCTL */
129 extern struct list_head nf_hooks[NPROTO][NF_MAX_HOOKS];
131 /* those NF_LOG_* defines and struct nf_loginfo are legacy definitios that will
132 * disappear once iptables is replaced with pkttables. Please DO NOT use them
133 * for any new code! */
134 #define NF_LOG_TCPSEQ 0x01 /* Log TCP sequence numbers */
135 #define NF_LOG_TCPOPT 0x02 /* Log TCP options */
136 #define NF_LOG_IPOPT 0x04 /* Log IP options */
137 #define NF_LOG_UID 0x08 /* Log UID owning local socket */
138 #define NF_LOG_MASK 0x0f
140 #define NF_LOG_TYPE_LOG 0x01
141 #define NF_LOG_TYPE_ULOG 0x02
149 u_int16_t qthreshold;
158 typedef void nf_logfn(unsigned int pf,
159 unsigned int hooknum,
160 const struct sk_buff *skb,
161 const struct net_device *in,
162 const struct net_device *out,
163 const struct nf_loginfo *li,
172 /* Function to register/unregister log function. */
173 int nf_log_register(int pf, struct nf_logger *logger);
174 void nf_log_unregister(struct nf_logger *logger);
175 void nf_log_unregister_pf(int pf);
177 /* Calls the registered backend logging function */
178 void nf_log_packet(int pf,
179 unsigned int hooknum,
180 const struct sk_buff *skb,
181 const struct net_device *in,
182 const struct net_device *out,
183 struct nf_loginfo *li,
184 const char *fmt, ...);
186 int nf_hook_slow(int pf, unsigned int hook, struct sk_buff **pskb,
187 struct net_device *indev, struct net_device *outdev,
188 int (*okfn)(struct sk_buff *), int thresh);
191 * nf_hook_thresh - call a netfilter hook
193 * Returns 1 if the hook has allowed the packet to pass. The function
194 * okfn must be invoked by the caller in this case. Any other return
195 * value indicates the packet has been consumed by the hook.
197 static inline int nf_hook_thresh(int pf, unsigned int hook,
198 struct sk_buff **pskb,
199 struct net_device *indev,
200 struct net_device *outdev,
201 int (*okfn)(struct sk_buff *), int thresh,
206 #ifndef CONFIG_NETFILTER_DEBUG
207 if (list_empty(&nf_hooks[pf][hook]))
210 return nf_hook_slow(pf, hook, pskb, indev, outdev, okfn, thresh);
213 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
214 struct net_device *indev, struct net_device *outdev,
215 int (*okfn)(struct sk_buff *))
217 return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1);
220 /* Activate hook; either okfn or kfree_skb called, unless a hook
221 returns NF_STOLEN (in which case, it's up to the hook to deal with
224 Returns -ERRNO if packet dropped. Zero means queued, stolen or
229 > I don't want nf_hook to return anything because people might forget
230 > about async and trust the return value to mean "packet was ok".
233 Just document it clearly, then you can expect some sense from kernel
237 /* This is gross, but inline doesn't cut it for avoiding the function
238 call in fast path: gcc doesn't inline (needs value tracking?). --RR */
240 /* HX: It's slightly less gross now. */
242 #define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
244 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\
245 __ret = (okfn)(skb); \
248 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
250 if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
251 __ret = (okfn)(skb); \
254 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) \
255 NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, INT_MIN)
257 /* Call setsockopt() */
258 int nf_setsockopt(struct sock *sk, int pf, int optval, char __user *opt,
260 int nf_getsockopt(struct sock *sk, int pf, int optval, char __user *opt,
263 int compat_nf_setsockopt(struct sock *sk, int pf, int optval,
264 char __user *opt, int len);
265 int compat_nf_getsockopt(struct sock *sk, int pf, int optval,
266 char __user *opt, int *len);
269 struct nf_queue_handler {
270 int (*outfn)(struct sk_buff *skb, struct nf_info *info,
271 unsigned int queuenum, void *data);
275 extern int nf_register_queue_handler(int pf,
276 struct nf_queue_handler *qh);
277 extern int nf_unregister_queue_handler(int pf,
278 struct nf_queue_handler *qh);
279 extern void nf_unregister_queue_handlers(struct nf_queue_handler *qh);
280 extern void nf_reinject(struct sk_buff *skb,
281 struct nf_info *info,
282 unsigned int verdict);
284 /* FIXME: Before cache is ever used, this must be implemented for real. */
285 extern void nf_invalidate_cache(int pf);
287 /* Call this before modifying an existing packet: ensures it is
288 modifiable and linear to the point you care about (writable_len).
289 Returns true or false. */
290 extern int skb_make_writable(struct sk_buff *skb, unsigned int writable_len);
292 static inline void nf_csum_replace4(__sum16 *sum, __be32 from, __be32 to)
294 __be32 diff[] = { ~from, to };
296 *sum = csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum_unfold(*sum)));
299 static inline void nf_csum_replace2(__sum16 *sum, __be16 from, __be16 to)
301 nf_csum_replace4(sum, (__force __be32)from, (__force __be32)to);
304 extern void nf_proto_csum_replace4(__sum16 *sum, struct sk_buff *skb,
305 __be32 from, __be32 to, int pseudohdr);
307 static inline void nf_proto_csum_replace2(__sum16 *sum, struct sk_buff *skb,
308 __be16 from, __be16 to, int pseudohdr)
310 nf_proto_csum_replace4(sum, skb, (__force __be32)from,
311 (__force __be32)to, pseudohdr);
315 unsigned short family;
316 __sum16 (*checksum)(struct sk_buff *skb, unsigned int hook,
317 unsigned int dataoff, u_int8_t protocol);
318 void (*saveroute)(const struct sk_buff *skb,
319 struct nf_info *info);
320 int (*reroute)(struct sk_buff **skb,
321 const struct nf_info *info);
325 extern struct nf_afinfo *nf_afinfo[];
326 static inline struct nf_afinfo *nf_get_afinfo(unsigned short family)
328 return rcu_dereference(nf_afinfo[family]);
331 static inline __sum16
332 nf_checksum(struct sk_buff *skb, unsigned int hook, unsigned int dataoff,
333 u_int8_t protocol, unsigned short family)
335 struct nf_afinfo *afinfo;
339 afinfo = nf_get_afinfo(family);
341 csum = afinfo->checksum(skb, hook, dataoff, protocol);
346 extern int nf_register_afinfo(struct nf_afinfo *afinfo);
347 extern void nf_unregister_afinfo(struct nf_afinfo *afinfo);
349 #define nf_info_reroute(x) ((void *)x + sizeof(struct nf_info))
351 #include <net/flow.h>
352 extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
355 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
357 #if defined(CONFIG_IP_NF_NAT_NEEDED) || defined(CONFIG_NF_NAT_NEEDED)
358 void (*decodefn)(struct sk_buff *, struct flowi *);
360 if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
365 #ifdef CONFIG_PROC_FS
366 #include <linux/proc_fs.h>
367 extern struct proc_dir_entry *proc_net_netfilter;
370 #else /* !CONFIG_NETFILTER */
371 #define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
372 #define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
373 static inline int nf_hook_thresh(int pf, unsigned int hook,
374 struct sk_buff **pskb,
375 struct net_device *indev,
376 struct net_device *outdev,
377 int (*okfn)(struct sk_buff *), int thresh,
382 static inline int nf_hook(int pf, unsigned int hook, struct sk_buff **pskb,
383 struct net_device *indev, struct net_device *outdev,
384 int (*okfn)(struct sk_buff *))
390 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {}
391 #endif /*CONFIG_NETFILTER*/
393 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
394 extern void (*ip_ct_attach)(struct sk_buff *, struct sk_buff *);
395 extern void nf_ct_attach(struct sk_buff *, struct sk_buff *);
396 extern void (*nf_ct_destroy)(struct nf_conntrack *);
398 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
401 #endif /*__KERNEL__*/
402 #endif /*__LINUX_NETFILTER_H*/