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TOMOYO Linux Cross Reference
Linux/include/linux/netfilter.h

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  1 /* SPDX-License-Identifier: GPL-2.0 */
  2 #ifndef __LINUX_NETFILTER_H
  3 #define __LINUX_NETFILTER_H
  4 
  5 #include <linux/init.h>
  6 #include <linux/skbuff.h>
  7 #include <linux/net.h>
  8 #include <linux/if.h>
  9 #include <linux/in.h>
 10 #include <linux/in6.h>
 11 #include <linux/wait.h>
 12 #include <linux/list.h>
 13 #include <linux/static_key.h>
 14 #include <linux/netfilter_defs.h>
 15 #include <linux/netdevice.h>
 16 #include <linux/sockptr.h>
 17 #include <net/net_namespace.h>
 18 
 19 static inline int NF_DROP_GETERR(int verdict)
 20 {
 21         return -(verdict >> NF_VERDICT_QBITS);
 22 }
 23 
 24 static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
 25                                    const union nf_inet_addr *a2)
 26 {
 27 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 28         const unsigned long *ul1 = (const unsigned long *)a1;
 29         const unsigned long *ul2 = (const unsigned long *)a2;
 30 
 31         return ((ul1[0] ^ ul2[0]) | (ul1[1] ^ ul2[1])) == 0UL;
 32 #else
 33         return a1->all[0] == a2->all[0] &&
 34                a1->all[1] == a2->all[1] &&
 35                a1->all[2] == a2->all[2] &&
 36                a1->all[3] == a2->all[3];
 37 #endif
 38 }
 39 
 40 static inline void nf_inet_addr_mask(const union nf_inet_addr *a1,
 41                                      union nf_inet_addr *result,
 42                                      const union nf_inet_addr *mask)
 43 {
 44 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
 45         const unsigned long *ua = (const unsigned long *)a1;
 46         unsigned long *ur = (unsigned long *)result;
 47         const unsigned long *um = (const unsigned long *)mask;
 48 
 49         ur[0] = ua[0] & um[0];
 50         ur[1] = ua[1] & um[1];
 51 #else
 52         result->all[0] = a1->all[0] & mask->all[0];
 53         result->all[1] = a1->all[1] & mask->all[1];
 54         result->all[2] = a1->all[2] & mask->all[2];
 55         result->all[3] = a1->all[3] & mask->all[3];
 56 #endif
 57 }
 58 
 59 int netfilter_init(void);
 60 
 61 struct sk_buff;
 62 
 63 struct nf_hook_ops;
 64 
 65 struct sock;
 66 
 67 struct nf_hook_state {
 68         unsigned int hook;
 69         u_int8_t pf;
 70         struct net_device *in;
 71         struct net_device *out;
 72         struct sock *sk;
 73         struct net *net;
 74         int (*okfn)(struct net *, struct sock *, struct sk_buff *);
 75 };
 76 
 77 typedef unsigned int nf_hookfn(void *priv,
 78                                struct sk_buff *skb,
 79                                const struct nf_hook_state *state);
 80 struct nf_hook_ops {
 81         /* User fills in from here down. */
 82         nf_hookfn               *hook;
 83         struct net_device       *dev;
 84         void                    *priv;
 85         u_int8_t                pf;
 86         unsigned int            hooknum;
 87         /* Hooks are ordered in ascending priority. */
 88         int                     priority;
 89 };
 90 
 91 struct nf_hook_entry {
 92         nf_hookfn                       *hook;
 93         void                            *priv;
 94 };
 95 
 96 struct nf_hook_entries_rcu_head {
 97         struct rcu_head head;
 98         void    *allocation;
 99 };
100 
101 struct nf_hook_entries {
102         u16                             num_hook_entries;
103         /* padding */
104         struct nf_hook_entry            hooks[];
105 
106         /* trailer: pointers to original orig_ops of each hook,
107          * followed by rcu_head and scratch space used for freeing
108          * the structure via call_rcu.
109          *
110          *   This is not part of struct nf_hook_entry since its only
111          *   needed in slow path (hook register/unregister):
112          * const struct nf_hook_ops     *orig_ops[]
113          *
114          *   For the same reason, we store this at end -- its
115          *   only needed when a hook is deleted, not during
116          *   packet path processing:
117          * struct nf_hook_entries_rcu_head     head
118          */
119 };
120 
121 #ifdef CONFIG_NETFILTER
122 static inline struct nf_hook_ops **nf_hook_entries_get_hook_ops(const struct nf_hook_entries *e)
123 {
124         unsigned int n = e->num_hook_entries;
125         const void *hook_end;
126 
127         hook_end = &e->hooks[n]; /* this is *past* ->hooks[]! */
128 
129         return (struct nf_hook_ops **)hook_end;
130 }
131 
132 static inline int
133 nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb,
134                      struct nf_hook_state *state)
135 {
136         return entry->hook(entry->priv, skb, state);
137 }
138 
139 static inline void nf_hook_state_init(struct nf_hook_state *p,
140                                       unsigned int hook,
141                                       u_int8_t pf,
142                                       struct net_device *indev,
143                                       struct net_device *outdev,
144                                       struct sock *sk,
145                                       struct net *net,
146                                       int (*okfn)(struct net *, struct sock *, struct sk_buff *))
147 {
148         p->hook = hook;
149         p->pf = pf;
150         p->in = indev;
151         p->out = outdev;
152         p->sk = sk;
153         p->net = net;
154         p->okfn = okfn;
155 }
156 
157 
158 
159 struct nf_sockopt_ops {
160         struct list_head list;
161 
162         u_int8_t pf;
163 
164         /* Non-inclusive ranges: use 0/0/NULL to never get called. */
165         int set_optmin;
166         int set_optmax;
167         int (*set)(struct sock *sk, int optval, sockptr_t arg,
168                    unsigned int len);
169         int get_optmin;
170         int get_optmax;
171         int (*get)(struct sock *sk, int optval, void __user *user, int *len);
172         /* Use the module struct to lock set/get code in place */
173         struct module *owner;
174 };
175 
176 /* Function to register/unregister hook points. */
177 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
178 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
179 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
180                           unsigned int n);
181 void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
182                              unsigned int n);
183 
184 /* Functions to register get/setsockopt ranges (non-inclusive).  You
185    need to check permissions yourself! */
186 int nf_register_sockopt(struct nf_sockopt_ops *reg);
187 void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
188 
189 #ifdef CONFIG_JUMP_LABEL
190 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
191 #endif
192 
193 int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
194                  const struct nf_hook_entries *e, unsigned int i);
195 
196 void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state,
197                        const struct nf_hook_entries *e);
198 /**
199  *      nf_hook - call a netfilter hook
200  *
201  *      Returns 1 if the hook has allowed the packet to pass.  The function
202  *      okfn must be invoked by the caller in this case.  Any other return
203  *      value indicates the packet has been consumed by the hook.
204  */
205 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
206                           struct sock *sk, struct sk_buff *skb,
207                           struct net_device *indev, struct net_device *outdev,
208                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
209 {
210         struct nf_hook_entries *hook_head = NULL;
211         int ret = 1;
212 
213 #ifdef CONFIG_JUMP_LABEL
214         if (__builtin_constant_p(pf) &&
215             __builtin_constant_p(hook) &&
216             !static_key_false(&nf_hooks_needed[pf][hook]))
217                 return 1;
218 #endif
219 
220         rcu_read_lock();
221         switch (pf) {
222         case NFPROTO_IPV4:
223                 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]);
224                 break;
225         case NFPROTO_IPV6:
226                 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
227                 break;
228         case NFPROTO_ARP:
229 #ifdef CONFIG_NETFILTER_FAMILY_ARP
230                 if (WARN_ON_ONCE(hook >= ARRAY_SIZE(net->nf.hooks_arp)))
231                         break;
232                 hook_head = rcu_dereference(net->nf.hooks_arp[hook]);
233 #endif
234                 break;
235         case NFPROTO_BRIDGE:
236 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
237                 hook_head = rcu_dereference(net->nf.hooks_bridge[hook]);
238 #endif
239                 break;
240 #if IS_ENABLED(CONFIG_DECNET)
241         case NFPROTO_DECNET:
242                 hook_head = rcu_dereference(net->nf.hooks_decnet[hook]);
243                 break;
244 #endif
245         default:
246                 WARN_ON_ONCE(1);
247                 break;
248         }
249 
250         if (hook_head) {
251                 struct nf_hook_state state;
252 
253                 nf_hook_state_init(&state, hook, pf, indev, outdev,
254                                    sk, net, okfn);
255 
256                 ret = nf_hook_slow(skb, &state, hook_head, 0);
257         }
258         rcu_read_unlock();
259 
260         return ret;
261 }
262 
263 /* Activate hook; either okfn or kfree_skb called, unless a hook
264    returns NF_STOLEN (in which case, it's up to the hook to deal with
265    the consequences).
266 
267    Returns -ERRNO if packet dropped.  Zero means queued, stolen or
268    accepted.
269 */
270 
271 /* RR:
272    > I don't want nf_hook to return anything because people might forget
273    > about async and trust the return value to mean "packet was ok".
274 
275    AK:
276    Just document it clearly, then you can expect some sense from kernel
277    coders :)
278 */
279 
280 static inline int
281 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
282              struct sk_buff *skb, struct net_device *in, struct net_device *out,
283              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
284              bool cond)
285 {
286         int ret;
287 
288         if (!cond ||
289             ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1))
290                 ret = okfn(net, sk, skb);
291         return ret;
292 }
293 
294 static inline int
295 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
296         struct net_device *in, struct net_device *out,
297         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
298 {
299         int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn);
300         if (ret == 1)
301                 ret = okfn(net, sk, skb);
302         return ret;
303 }
304 
305 static inline void
306 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
307              struct list_head *head, struct net_device *in, struct net_device *out,
308              int (*okfn)(struct net *, struct sock *, struct sk_buff *))
309 {
310         struct nf_hook_entries *hook_head = NULL;
311 
312 #ifdef CONFIG_JUMP_LABEL
313         if (__builtin_constant_p(pf) &&
314             __builtin_constant_p(hook) &&
315             !static_key_false(&nf_hooks_needed[pf][hook]))
316                 return;
317 #endif
318 
319         rcu_read_lock();
320         switch (pf) {
321         case NFPROTO_IPV4:
322                 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]);
323                 break;
324         case NFPROTO_IPV6:
325                 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
326                 break;
327         default:
328                 WARN_ON_ONCE(1);
329                 break;
330         }
331 
332         if (hook_head) {
333                 struct nf_hook_state state;
334 
335                 nf_hook_state_init(&state, hook, pf, in, out, sk, net, okfn);
336 
337                 nf_hook_slow_list(head, &state, hook_head);
338         }
339         rcu_read_unlock();
340 }
341 
342 /* Call setsockopt() */
343 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, sockptr_t opt,
344                   unsigned int len);
345 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
346                   int *len);
347 
348 struct flowi;
349 struct nf_queue_entry;
350 
351 __sum16 nf_checksum(struct sk_buff *skb, unsigned int hook,
352                     unsigned int dataoff, u_int8_t protocol,
353                     unsigned short family);
354 
355 __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
356                             unsigned int dataoff, unsigned int len,
357                             u_int8_t protocol, unsigned short family);
358 int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
359              bool strict, unsigned short family);
360 int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry);
361 
362 #include <net/flow.h>
363 
364 struct nf_conn;
365 enum nf_nat_manip_type;
366 struct nlattr;
367 enum ip_conntrack_dir;
368 
369 struct nf_nat_hook {
370         int (*parse_nat_setup)(struct nf_conn *ct, enum nf_nat_manip_type manip,
371                                const struct nlattr *attr);
372         void (*decode_session)(struct sk_buff *skb, struct flowi *fl);
373         unsigned int (*manip_pkt)(struct sk_buff *skb, struct nf_conn *ct,
374                                   enum nf_nat_manip_type mtype,
375                                   enum ip_conntrack_dir dir);
376 };
377 
378 extern struct nf_nat_hook __rcu *nf_nat_hook;
379 
380 static inline void
381 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
382 {
383 #if IS_ENABLED(CONFIG_NF_NAT)
384         struct nf_nat_hook *nat_hook;
385 
386         rcu_read_lock();
387         nat_hook = rcu_dereference(nf_nat_hook);
388         if (nat_hook && nat_hook->decode_session)
389                 nat_hook->decode_session(skb, fl);
390         rcu_read_unlock();
391 #endif
392 }
393 
394 #else /* !CONFIG_NETFILTER */
395 static inline int
396 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
397              struct sk_buff *skb, struct net_device *in, struct net_device *out,
398              int (*okfn)(struct net *, struct sock *, struct sk_buff *),
399              bool cond)
400 {
401         return okfn(net, sk, skb);
402 }
403 
404 static inline int
405 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
406         struct sk_buff *skb, struct net_device *in, struct net_device *out,
407         int (*okfn)(struct net *, struct sock *, struct sk_buff *))
408 {
409         return okfn(net, sk, skb);
410 }
411 
412 static inline void
413 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
414              struct list_head *head, struct net_device *in, struct net_device *out,
415              int (*okfn)(struct net *, struct sock *, struct sk_buff *))
416 {
417         /* nothing to do */
418 }
419 
420 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
421                           struct sock *sk, struct sk_buff *skb,
422                           struct net_device *indev, struct net_device *outdev,
423                           int (*okfn)(struct net *, struct sock *, struct sk_buff *))
424 {
425         return 1;
426 }
427 struct flowi;
428 static inline void
429 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
430 {
431 }
432 #endif /*CONFIG_NETFILTER*/
433 
434 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
435 #include <linux/netfilter/nf_conntrack_zones_common.h>
436 
437 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu;
438 void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
439 struct nf_conntrack_tuple;
440 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
441                          const struct sk_buff *skb);
442 #else
443 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
444 struct nf_conntrack_tuple;
445 static inline bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
446                                        const struct sk_buff *skb)
447 {
448         return false;
449 }
450 #endif
451 
452 struct nf_conn;
453 enum ip_conntrack_info;
454 
455 struct nf_ct_hook {
456         int (*update)(struct net *net, struct sk_buff *skb);
457         void (*destroy)(struct nf_conntrack *);
458         bool (*get_tuple_skb)(struct nf_conntrack_tuple *,
459                               const struct sk_buff *);
460 };
461 extern struct nf_ct_hook __rcu *nf_ct_hook;
462 
463 struct nlattr;
464 
465 struct nfnl_ct_hook {
466         struct nf_conn *(*get_ct)(const struct sk_buff *skb,
467                                   enum ip_conntrack_info *ctinfo);
468         size_t (*build_size)(const struct nf_conn *ct);
469         int (*build)(struct sk_buff *skb, struct nf_conn *ct,
470                      enum ip_conntrack_info ctinfo,
471                      u_int16_t ct_attr, u_int16_t ct_info_attr);
472         int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
473         int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
474                              u32 portid, u32 report);
475         void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
476                            enum ip_conntrack_info ctinfo, s32 off);
477 };
478 extern struct nfnl_ct_hook __rcu *nfnl_ct_hook;
479 
480 /**
481  * nf_skb_duplicated - TEE target has sent a packet
482  *
483  * When a xtables target sends a packet, the OUTPUT and POSTROUTING
484  * hooks are traversed again, i.e. nft and xtables are invoked recursively.
485  *
486  * This is used by xtables TEE target to prevent the duplicated skb from
487  * being duplicated again.
488  */
489 DECLARE_PER_CPU(bool, nf_skb_duplicated);
490 
491 #endif /*__LINUX_NETFILTER_H*/
492 

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