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/module.h>
15#include <linux/netfilter_defs.h>
16#include <linux/netdevice.h>
17#include <linux/sockptr.h>
18#include <net/net_namespace.h>
19
20static inline int NF_DROP_GETERR(int verdict)
21{
22 return -(verdict >> NF_VERDICT_QBITS);
23}
24
25static __always_inline int
26NF_DROP_REASON(struct sk_buff *skb, enum skb_drop_reason reason, u32 err)
27{
28 BUILD_BUG_ON(err > 0xffff);
29
30 kfree_skb_reason(skb, reason);
31
32 return ((err << 16) | NF_STOLEN);
33}
34
35static inline int nf_inet_addr_cmp(const union nf_inet_addr *a1,
36 const union nf_inet_addr *a2)
37{
38#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
39 const unsigned long *ul1 = (const unsigned long *)a1;
40 const unsigned long *ul2 = (const unsigned long *)a2;
41
42 return ((ul1[0] ^ ul2[0]) | (ul1[1] ^ ul2[1])) == 0UL;
43#else
44 return a1->all[0] == a2->all[0] &&
45 a1->all[1] == a2->all[1] &&
46 a1->all[2] == a2->all[2] &&
47 a1->all[3] == a2->all[3];
48#endif
49}
50
51static inline void nf_inet_addr_mask(const union nf_inet_addr *a1,
52 union nf_inet_addr *result,
53 const union nf_inet_addr *mask)
54{
55#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && BITS_PER_LONG == 64
56 const unsigned long *ua = (const unsigned long *)a1;
57 unsigned long *ur = (unsigned long *)result;
58 const unsigned long *um = (const unsigned long *)mask;
59
60 ur[0] = ua[0] & um[0];
61 ur[1] = ua[1] & um[1];
62#else
63 result->all[0] = a1->all[0] & mask->all[0];
64 result->all[1] = a1->all[1] & mask->all[1];
65 result->all[2] = a1->all[2] & mask->all[2];
66 result->all[3] = a1->all[3] & mask->all[3];
67#endif
68}
69
70int netfilter_init(void);
71
72struct sk_buff;
73
74struct nf_hook_ops;
75
76struct sock;
77
78struct nf_hook_state {
79 u8 hook;
80 u8 pf;
81 struct net_device *in;
82 struct net_device *out;
83 struct sock *sk;
84 struct net *net;
85 int (*okfn)(struct net *, struct sock *, struct sk_buff *);
86};
87
88typedef unsigned int nf_hookfn(void *priv,
89 struct sk_buff *skb,
90 const struct nf_hook_state *state);
91enum nf_hook_ops_type {
92 NF_HOOK_OP_UNDEFINED,
93 NF_HOOK_OP_NF_TABLES,
94 NF_HOOK_OP_BPF,
95};
96
97struct nf_hook_ops {
98 struct list_head list;
99 struct rcu_head rcu;
100
101 /* User fills in from here down. */
102 nf_hookfn *hook;
103 struct net_device *dev;
104 void *priv;
105 u8 pf;
106 enum nf_hook_ops_type hook_ops_type:8;
107 unsigned int hooknum;
108 /* Hooks are ordered in ascending priority. */
109 int priority;
110};
111
112struct nf_hook_entry {
113 nf_hookfn *hook;
114 void *priv;
115};
116
117struct nf_hook_entries_rcu_head {
118 struct rcu_head head;
119 void *allocation;
120};
121
122struct nf_hook_entries {
123 u16 num_hook_entries;
124 /* padding */
125 struct nf_hook_entry hooks[];
126
127 /* trailer: pointers to original orig_ops of each hook,
128 * followed by rcu_head and scratch space used for freeing
129 * the structure via call_rcu.
130 *
131 * This is not part of struct nf_hook_entry since its only
132 * needed in slow path (hook register/unregister):
133 * const struct nf_hook_ops *orig_ops[]
134 *
135 * For the same reason, we store this at end -- its
136 * only needed when a hook is deleted, not during
137 * packet path processing:
138 * struct nf_hook_entries_rcu_head head
139 */
140};
141
142#ifdef CONFIG_NETFILTER
143static inline struct nf_hook_ops **nf_hook_entries_get_hook_ops(const struct nf_hook_entries *e)
144{
145 unsigned int n = e->num_hook_entries;
146 const void *hook_end;
147
148 hook_end = &e->hooks[n]; /* this is *past* ->hooks[]! */
149
150 return (struct nf_hook_ops **)hook_end;
151}
152
153static inline int
154nf_hook_entry_hookfn(const struct nf_hook_entry *entry, struct sk_buff *skb,
155 struct nf_hook_state *state)
156{
157 return entry->hook(entry->priv, skb, state);
158}
159
160static inline void nf_hook_state_init(struct nf_hook_state *p,
161 unsigned int hook,
162 u_int8_t pf,
163 struct net_device *indev,
164 struct net_device *outdev,
165 struct sock *sk,
166 struct net *net,
167 int (*okfn)(struct net *, struct sock *, struct sk_buff *))
168{
169 p->hook = hook;
170 p->pf = pf;
171 p->in = indev;
172 p->out = outdev;
173 p->sk = sk;
174 p->net = net;
175 p->okfn = okfn;
176}
177
178
179
180struct nf_sockopt_ops {
181 struct list_head list;
182
183 u_int8_t pf;
184
185 /* Non-inclusive ranges: use 0/0/NULL to never get called. */
186 int set_optmin;
187 int set_optmax;
188 int (*set)(struct sock *sk, int optval, sockptr_t arg,
189 unsigned int len);
190 int get_optmin;
191 int get_optmax;
192 int (*get)(struct sock *sk, int optval, void __user *user, int *len);
193 /* Use the module struct to lock set/get code in place */
194 struct module *owner;
195};
196
197/* Function to register/unregister hook points. */
198int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops);
199void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops);
200int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg,
201 unsigned int n);
202void nf_unregister_net_hooks(struct net *net, const struct nf_hook_ops *reg,
203 unsigned int n);
204
205/* Functions to register get/setsockopt ranges (non-inclusive). You
206 need to check permissions yourself! */
207int nf_register_sockopt(struct nf_sockopt_ops *reg);
208void nf_unregister_sockopt(struct nf_sockopt_ops *reg);
209
210#ifdef CONFIG_JUMP_LABEL
211extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS];
212#endif
213
214int nf_hook_slow(struct sk_buff *skb, struct nf_hook_state *state,
215 const struct nf_hook_entries *e, unsigned int i);
216
217void nf_hook_slow_list(struct list_head *head, struct nf_hook_state *state,
218 const struct nf_hook_entries *e);
219/**
220 * nf_hook - call a netfilter hook
221 *
222 * Returns 1 if the hook has allowed the packet to pass. The function
223 * okfn must be invoked by the caller in this case. Any other return
224 * value indicates the packet has been consumed by the hook.
225 */
226static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
227 struct sock *sk, struct sk_buff *skb,
228 struct net_device *indev, struct net_device *outdev,
229 int (*okfn)(struct net *, struct sock *, struct sk_buff *))
230{
231 struct nf_hook_entries *hook_head = NULL;
232 int ret = 1;
233
234#ifdef CONFIG_JUMP_LABEL
235 if (__builtin_constant_p(pf) &&
236 __builtin_constant_p(hook) &&
237 !static_key_false(key: &nf_hooks_needed[pf][hook]))
238 return 1;
239#endif
240
241 rcu_read_lock();
242 switch (pf) {
243 case NFPROTO_IPV4:
244 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]);
245 break;
246 case NFPROTO_IPV6:
247 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
248 break;
249 case NFPROTO_ARP:
250#ifdef CONFIG_NETFILTER_FAMILY_ARP
251 if (WARN_ON_ONCE(hook >= ARRAY_SIZE(net->nf.hooks_arp)))
252 break;
253 hook_head = rcu_dereference(net->nf.hooks_arp[hook]);
254#endif
255 break;
256 case NFPROTO_BRIDGE:
257#ifdef CONFIG_NETFILTER_FAMILY_BRIDGE
258 hook_head = rcu_dereference(net->nf.hooks_bridge[hook]);
259#endif
260 break;
261 default:
262 WARN_ON_ONCE(1);
263 break;
264 }
265
266 if (hook_head) {
267 struct nf_hook_state state;
268
269 nf_hook_state_init(p: &state, hook, pf, indev, outdev,
270 sk, net, okfn);
271
272 ret = nf_hook_slow(skb, state: &state, e: hook_head, i: 0);
273 }
274 rcu_read_unlock();
275
276 return ret;
277}
278
279/* Activate hook; either okfn or kfree_skb called, unless a hook
280 returns NF_STOLEN (in which case, it's up to the hook to deal with
281 the consequences).
282
283 Returns -ERRNO if packet dropped. Zero means queued, stolen or
284 accepted.
285*/
286
287/* RR:
288 > I don't want nf_hook to return anything because people might forget
289 > about async and trust the return value to mean "packet was ok".
290
291 AK:
292 Just document it clearly, then you can expect some sense from kernel
293 coders :)
294*/
295
296static inline int
297NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
298 struct sk_buff *skb, struct net_device *in, struct net_device *out,
299 int (*okfn)(struct net *, struct sock *, struct sk_buff *),
300 bool cond)
301{
302 int ret;
303
304 if (!cond ||
305 ((ret = nf_hook(pf, hook, net, sk, skb, indev: in, outdev: out, okfn)) == 1))
306 ret = okfn(net, sk, skb);
307 return ret;
308}
309
310static inline int
311NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb,
312 struct net_device *in, struct net_device *out,
313 int (*okfn)(struct net *, struct sock *, struct sk_buff *))
314{
315 int ret = nf_hook(pf, hook, net, sk, skb, indev: in, outdev: out, okfn);
316 if (ret == 1)
317 ret = okfn(net, sk, skb);
318 return ret;
319}
320
321static inline void
322NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
323 struct list_head *head, struct net_device *in, struct net_device *out,
324 int (*okfn)(struct net *, struct sock *, struct sk_buff *))
325{
326 struct nf_hook_entries *hook_head = NULL;
327
328#ifdef CONFIG_JUMP_LABEL
329 if (__builtin_constant_p(pf) &&
330 __builtin_constant_p(hook) &&
331 !static_key_false(key: &nf_hooks_needed[pf][hook]))
332 return;
333#endif
334
335 rcu_read_lock();
336 switch (pf) {
337 case NFPROTO_IPV4:
338 hook_head = rcu_dereference(net->nf.hooks_ipv4[hook]);
339 break;
340 case NFPROTO_IPV6:
341 hook_head = rcu_dereference(net->nf.hooks_ipv6[hook]);
342 break;
343 default:
344 WARN_ON_ONCE(1);
345 break;
346 }
347
348 if (hook_head) {
349 struct nf_hook_state state;
350
351 nf_hook_state_init(p: &state, hook, pf, indev: in, outdev: out, sk, net, okfn);
352
353 nf_hook_slow_list(head, state: &state, e: hook_head);
354 }
355 rcu_read_unlock();
356}
357
358/* Call setsockopt() */
359int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, sockptr_t opt,
360 unsigned int len);
361int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt,
362 int *len);
363
364struct flowi;
365struct nf_queue_entry;
366
367__sum16 nf_checksum(struct sk_buff *skb, unsigned int hook,
368 unsigned int dataoff, u_int8_t protocol,
369 unsigned short family);
370
371__sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook,
372 unsigned int dataoff, unsigned int len,
373 u_int8_t protocol, unsigned short family);
374int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl,
375 bool strict, unsigned short family);
376
377#include <net/flow.h>
378
379struct nf_conn;
380enum nf_nat_manip_type;
381struct nlattr;
382
383struct nf_nat_hook {
384 int (*parse_nat_setup)(struct nf_conn *ct, enum nf_nat_manip_type manip,
385 const struct nlattr *attr);
386 void (*decode_session)(struct sk_buff *skb, struct flowi *fl);
387 void (*remove_nat_bysrc)(struct nf_conn *ct);
388};
389
390extern const struct nf_nat_hook __rcu *nf_nat_hook;
391
392static inline void
393nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
394{
395#if IS_ENABLED(CONFIG_NF_NAT)
396 const struct nf_nat_hook *nat_hook;
397
398 rcu_read_lock();
399 nat_hook = rcu_dereference(nf_nat_hook);
400 if (nat_hook && nat_hook->decode_session)
401 nat_hook->decode_session(skb, fl);
402 rcu_read_unlock();
403#endif
404}
405
406#else /* !CONFIG_NETFILTER */
407static inline int
408NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
409 struct sk_buff *skb, struct net_device *in, struct net_device *out,
410 int (*okfn)(struct net *, struct sock *, struct sk_buff *),
411 bool cond)
412{
413 return okfn(net, sk, skb);
414}
415
416static inline int
417NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
418 struct sk_buff *skb, struct net_device *in, struct net_device *out,
419 int (*okfn)(struct net *, struct sock *, struct sk_buff *))
420{
421 return okfn(net, sk, skb);
422}
423
424static inline void
425NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk,
426 struct list_head *head, struct net_device *in, struct net_device *out,
427 int (*okfn)(struct net *, struct sock *, struct sk_buff *))
428{
429 /* nothing to do */
430}
431
432static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net,
433 struct sock *sk, struct sk_buff *skb,
434 struct net_device *indev, struct net_device *outdev,
435 int (*okfn)(struct net *, struct sock *, struct sk_buff *))
436{
437 return 1;
438}
439struct flowi;
440static inline void
441nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family)
442{
443}
444#endif /*CONFIG_NETFILTER*/
445
446#if IS_ENABLED(CONFIG_NF_CONNTRACK)
447#include <linux/netfilter/nf_conntrack_zones_common.h>
448
449void nf_ct_attach(struct sk_buff *, const struct sk_buff *);
450void nf_ct_set_closing(struct nf_conntrack *nfct);
451struct nf_conntrack_tuple;
452bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
453 const struct sk_buff *skb);
454#else
455static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
456static inline void nf_ct_set_closing(struct nf_conntrack *nfct) {}
457struct nf_conntrack_tuple;
458static inline bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple,
459 const struct sk_buff *skb)
460{
461 return false;
462}
463#endif
464
465struct nf_conn;
466enum ip_conntrack_info;
467
468struct nf_ct_hook {
469 int (*update)(struct net *net, struct sk_buff *skb);
470 void (*destroy)(struct nf_conntrack *);
471 bool (*get_tuple_skb)(struct nf_conntrack_tuple *,
472 const struct sk_buff *);
473 void (*attach)(struct sk_buff *nskb, const struct sk_buff *skb);
474 void (*set_closing)(struct nf_conntrack *nfct);
475 int (*confirm)(struct sk_buff *skb);
476 u32 (*get_id)(const struct nf_conntrack *nfct);
477};
478extern const struct nf_ct_hook __rcu *nf_ct_hook;
479
480struct nlattr;
481
482struct nfnl_ct_hook {
483 size_t (*build_size)(const struct nf_conn *ct);
484 int (*build)(struct sk_buff *skb, struct nf_conn *ct,
485 enum ip_conntrack_info ctinfo,
486 u_int16_t ct_attr, u_int16_t ct_info_attr);
487 int (*parse)(const struct nlattr *attr, struct nf_conn *ct);
488 int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct,
489 u32 portid, u32 report);
490 void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct,
491 enum ip_conntrack_info ctinfo, s32 off);
492};
493extern const struct nfnl_ct_hook __rcu *nfnl_ct_hook;
494
495struct nf_defrag_hook {
496 struct module *owner;
497 int (*enable)(struct net *net);
498 void (*disable)(struct net *net);
499};
500
501extern const struct nf_defrag_hook __rcu *nf_defrag_v4_hook;
502extern const struct nf_defrag_hook __rcu *nf_defrag_v6_hook;
503
504/*
505 * Contains bitmask of ctnetlink event subscribers, if any.
506 * Can't be pernet due to NETLINK_LISTEN_ALL_NSID setsockopt flag.
507 */
508extern u8 nf_ctnetlink_has_listener;
509#endif /*__LINUX_NETFILTER_H*/
510

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source code of linux/include/linux/netfilter.h