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 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 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 33 static 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 43 int netfilter_init(void); 44 45 struct sk_buff; 46 47 struct nf_hook_ops; 48 49 struct sock; 50 51 struct 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 61 typedef unsigned int nf_hookfn(void *priv, 62 struct sk_buff *skb, 63 const struct nf_hook_state *state); 64 struct 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 75 struct nf_hook_entry { 76 nf_hookfn *hook; 77 void *priv; 78 }; 79 80 struct nf_hook_entries_rcu_head { 81 struct rcu_head head; 82 void *allocation; 83 }; 84 85 struct 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 }; 104 105 static 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 } 114 115 static inline int 116 nf_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 } 121 122 static 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 } 139 140 141 142 struct 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. */ 167 int nf_register_net_hook(struct net *net, const struct nf_hook_ops *ops); 168 void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *ops); 169 int nf_register_net_hooks(struct net *net, const struct nf_hook_ops *reg, 170 unsigned int n); 171 void 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! */ 176 int nf_register_sockopt(struct nf_sockopt_ops *reg); 177 void nf_unregister_sockopt(struct nf_sockopt_ops *reg); 178 179 #ifdef HAVE_JUMP_LABEL 180 extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; 181 #endif 182 183 int 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 */ 193 static 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 HAVE_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 hook_head = rcu_dereference(net->nf.hooks_arp[hook]); 219 #endif 220 break; 221 case NFPROTO_BRIDGE: 222 #ifdef CONFIG_NETFILTER_FAMILY_BRIDGE 223 hook_head = rcu_dereference(net->nf.hooks_bridge[hook]); 224 #endif 225 break; 226 #if IS_ENABLED(CONFIG_DECNET) 227 case NFPROTO_DECNET: 228 hook_head = rcu_dereference(net->nf.hooks_decnet[hook]); 229 break; 230 #endif 231 default: 232 WARN_ON_ONCE(1); 233 break; 234 } 235 236 if (hook_head) { 237 struct nf_hook_state state; 238 239 nf_hook_state_init(&state, hook, pf, indev, outdev, 240 sk, net, okfn); 241 242 ret = nf_hook_slow(skb, &state, hook_head, 0); 243 } 244 rcu_read_unlock(); 245 246 return ret; 247 } 248 249 /* Activate hook; either okfn or kfree_skb called, unless a hook 250 returns NF_STOLEN (in which case, it's up to the hook to deal with 251 the consequences). 252 253 Returns -ERRNO if packet dropped. Zero means queued, stolen or 254 accepted. 255 */ 256 257 /* RR: 258 > I don't want nf_hook to return anything because people might forget 259 > about async and trust the return value to mean "packet was ok". 260 261 AK: 262 Just document it clearly, then you can expect some sense from kernel 263 coders :) 264 */ 265 266 static inline int 267 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 268 struct sk_buff *skb, struct net_device *in, struct net_device *out, 269 int (*okfn)(struct net *, struct sock *, struct sk_buff *), 270 bool cond) 271 { 272 int ret; 273 274 if (!cond || 275 ((ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn)) == 1)) 276 ret = okfn(net, sk, skb); 277 return ret; 278 } 279 280 static inline int 281 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, struct sk_buff *skb, 282 struct net_device *in, struct net_device *out, 283 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 284 { 285 int ret = nf_hook(pf, hook, net, sk, skb, in, out, okfn); 286 if (ret == 1) 287 ret = okfn(net, sk, skb); 288 return ret; 289 } 290 291 static inline void 292 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 293 struct list_head *head, struct net_device *in, struct net_device *out, 294 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 295 { 296 struct sk_buff *skb, *next; 297 struct list_head sublist; 298 299 INIT_LIST_HEAD(&sublist); 300 list_for_each_entry_safe(skb, next, head, list) { 301 list_del(&skb->list); 302 if (nf_hook(pf, hook, net, sk, skb, in, out, okfn) == 1) 303 list_add_tail(&skb->list, &sublist); 304 } 305 /* Put passed packets back on main list */ 306 list_splice(&sublist, head); 307 } 308 309 /* Call setsockopt() */ 310 int nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 311 unsigned int len); 312 int nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, char __user *opt, 313 int *len); 314 #ifdef CONFIG_COMPAT 315 int compat_nf_setsockopt(struct sock *sk, u_int8_t pf, int optval, 316 char __user *opt, unsigned int len); 317 int compat_nf_getsockopt(struct sock *sk, u_int8_t pf, int optval, 318 char __user *opt, int *len); 319 #endif 320 321 /* Call this before modifying an existing packet: ensures it is 322 modifiable and linear to the point you care about (writable_len). 323 Returns true or false. */ 324 int skb_make_writable(struct sk_buff *skb, unsigned int writable_len); 325 326 struct flowi; 327 struct nf_queue_entry; 328 329 __sum16 nf_checksum(struct sk_buff *skb, unsigned int hook, 330 unsigned int dataoff, u_int8_t protocol, 331 unsigned short family); 332 333 __sum16 nf_checksum_partial(struct sk_buff *skb, unsigned int hook, 334 unsigned int dataoff, unsigned int len, 335 u_int8_t protocol, unsigned short family); 336 int nf_route(struct net *net, struct dst_entry **dst, struct flowi *fl, 337 bool strict, unsigned short family); 338 int nf_reroute(struct sk_buff *skb, struct nf_queue_entry *entry); 339 340 #include <net/flow.h> 341 342 struct nf_conn; 343 enum nf_nat_manip_type; 344 struct nlattr; 345 enum ip_conntrack_dir; 346 347 struct nf_nat_hook { 348 int (*parse_nat_setup)(struct nf_conn *ct, enum nf_nat_manip_type manip, 349 const struct nlattr *attr); 350 void (*decode_session)(struct sk_buff *skb, struct flowi *fl); 351 unsigned int (*manip_pkt)(struct sk_buff *skb, struct nf_conn *ct, 352 enum nf_nat_manip_type mtype, 353 enum ip_conntrack_dir dir); 354 }; 355 356 extern struct nf_nat_hook __rcu *nf_nat_hook; 357 358 static inline void 359 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 360 { 361 #ifdef CONFIG_NF_NAT_NEEDED 362 struct nf_nat_hook *nat_hook; 363 364 rcu_read_lock(); 365 nat_hook = rcu_dereference(nf_nat_hook); 366 if (nat_hook && nat_hook->decode_session) 367 nat_hook->decode_session(skb, fl); 368 rcu_read_unlock(); 369 #endif 370 } 371 372 #else /* !CONFIG_NETFILTER */ 373 static inline int 374 NF_HOOK_COND(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 375 struct sk_buff *skb, struct net_device *in, struct net_device *out, 376 int (*okfn)(struct net *, struct sock *, struct sk_buff *), 377 bool cond) 378 { 379 return okfn(net, sk, skb); 380 } 381 382 static inline int 383 NF_HOOK(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 384 struct sk_buff *skb, struct net_device *in, struct net_device *out, 385 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 386 { 387 return okfn(net, sk, skb); 388 } 389 390 static inline void 391 NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net *net, struct sock *sk, 392 struct list_head *head, struct net_device *in, struct net_device *out, 393 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 394 { 395 /* nothing to do */ 396 } 397 398 static inline int nf_hook(u_int8_t pf, unsigned int hook, struct net *net, 399 struct sock *sk, struct sk_buff *skb, 400 struct net_device *indev, struct net_device *outdev, 401 int (*okfn)(struct net *, struct sock *, struct sk_buff *)) 402 { 403 return 1; 404 } 405 struct flowi; 406 static inline void 407 nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, u_int8_t family) 408 { 409 } 410 #endif /*CONFIG_NETFILTER*/ 411 412 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 413 #include <linux/netfilter/nf_conntrack_zones_common.h> 414 415 extern void (*ip_ct_attach)(struct sk_buff *, const struct sk_buff *) __rcu; 416 void nf_ct_attach(struct sk_buff *, const struct sk_buff *); 417 struct nf_conntrack_tuple; 418 bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 419 const struct sk_buff *skb); 420 #else 421 static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {} 422 struct nf_conntrack_tuple; 423 static inline bool nf_ct_get_tuple_skb(struct nf_conntrack_tuple *dst_tuple, 424 const struct sk_buff *skb) 425 { 426 return false; 427 } 428 #endif 429 430 struct nf_conn; 431 enum ip_conntrack_info; 432 433 struct nf_ct_hook { 434 int (*update)(struct net *net, struct sk_buff *skb); 435 void (*destroy)(struct nf_conntrack *); 436 bool (*get_tuple_skb)(struct nf_conntrack_tuple *, 437 const struct sk_buff *); 438 }; 439 extern struct nf_ct_hook __rcu *nf_ct_hook; 440 441 struct nlattr; 442 443 struct nfnl_ct_hook { 444 struct nf_conn *(*get_ct)(const struct sk_buff *skb, 445 enum ip_conntrack_info *ctinfo); 446 size_t (*build_size)(const struct nf_conn *ct); 447 int (*build)(struct sk_buff *skb, struct nf_conn *ct, 448 enum ip_conntrack_info ctinfo, 449 u_int16_t ct_attr, u_int16_t ct_info_attr); 450 int (*parse)(const struct nlattr *attr, struct nf_conn *ct); 451 int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct, 452 u32 portid, u32 report); 453 void (*seq_adjust)(struct sk_buff *skb, struct nf_conn *ct, 454 enum ip_conntrack_info ctinfo, s32 off); 455 }; 456 extern struct nfnl_ct_hook __rcu *nfnl_ct_hook; 457 458 /** 459 * nf_skb_duplicated - TEE target has sent a packet 460 * 461 * When a xtables target sends a packet, the OUTPUT and POSTROUTING 462 * hooks are traversed again, i.e. nft and xtables are invoked recursively. 463 * 464 * This is used by xtables TEE target to prevent the duplicated skb from 465 * being duplicated again. 466 */ 467 DECLARE_PER_CPU(bool, nf_skb_duplicated); 468 469 #endif /*__LINUX_NETFILTER_H*/ 470