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